GNSS SENSOR
ARINC CHARACTERISTIC 743A-4
PUBLISHED: December 27, 2001
AN
DOCUMENT
Prepared by
AIRLINES ELECTRONIC ENGINEERING COMMITTEE
Published by
AERONAUTICAL RADIO, INC.
2551 RIVA ROAD, ANNAPOLIS, MARYLAND 21401
This document is based on material submitted by various
participants during the drafting process. Neither AEEC nor ARINC
has made any determination whether these materials could be
subject to valid claims of patent, copyright or other proprietary
rights by third parties, and no representation or warranty, express or
implied, is made in this regard. Any use of or reliance on this
document shall constitute an acceptance thereof “as is” and be
subject to this disclaimer.
Copyright 2001 by
AERONAUTICAL RADIO, INC.
2551 Riva Road
Annapolis, Maryland 21401-7465 USA
ARINC CHARACTERISTIC 743A-4©
GNSS SENSOR
Published: December 27, 2001
Prepared by the Airlines Electronic Engineering Committee
Characteristic 743A
Characteristic 743A
Adopted by the Airlines Electronic Engineering Committee:
Adopted by the Industry:
October 9, 1991
December 9, 1991
Summary of Document Supplements
Supplement
Adoption Date
Published
Characteristic 743A-1
Characteristic 743A-2
Characteristic 743A-3
Characteristic 743A-4
October 20, 1993
November 2, 1995
October 15, 1997
October 24, 2001
November 9, 1993
December 31, 1995
January 5, 1998
December 27, 2001
A description of the changes introduced by each supplement is included on goldenrod paper at the end of this document.
FOREWORD
Activities of AERONAUTICAL RADIO, INC. (ARINC)
and the
Purpose of ARINC Characteristics
Aeronautical Radio, Inc. is a corporation in which the United States scheduled airlines are
the principal stockholders. Other stockholders include a variety of other air transport companies,
aircraft manufacturers and non-U.S. airlines.
Activities of ARINC include the operation of an extensive system of domestic and overseas
aeronautical land radio stations, the fulfillment of systems requirements to accomplish ground and
airborne compatibility, the allocation and assignment of frequencies to meet those needs, the
coordination incident to standard airborne compatibility, the allocation and assignment of
frequencies to meet those needs, the coordination incident to standard airborne communications and
electronics systems and the exchange of technical information. ARINC sponsors the Airlines
Electronic Engineering Committee (AEEC), composed of airline technical personnel. The AEEC
formulates standards for electronic equipment and systems for the airlines. The establishment of
Equipment Characteristics is a principal function of this Committee.
An ARINC Equipment Characteristic is finalized after investigation and coordination with
the airlines who have a requirement or anticipate a requirement, with other aircraft operators, with
the Military services having similar requirements, and with the equipment manufacturers. It is
released as an ARINC Equipment Characteristic only when the interested airline companies are in
general agreement. Such a release does not commit any airline or ARINC to purchase equipment
so described nor does it establish or indicate recognition of the existence of an operational
requirement for such equipment, not does it constitute endorsement of any manufacturer’s product
designed or built to meet the Characteristic. An ARINC Characteristic has a twofold purpose,
which is:
(1)
To indicate to the prospective manufacturers of airline electronic equipment the
considered opinion of the airline technical people, coordinated on an industry basis,
concerning requisites of new equipment, and
(2)
To channel new equipment designs in a direction which can result in the maximum
possible standardization of those physical and electrical characteristics which
influence interchangeability of equipment without seriously hampering engineering
initiative.
ii
ARINC CHARACTERISTIC 743A
TABLE OF CONTENTS
ITEM
SUBJECT
PAGE
1.0
1.1
1.2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.2.7
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.4
1.5
1.6
1.7
1.8
INTRODUCTION
Purpose of This Document
Summary of GNSS System Operational Characteristics
Operational Consideration
Integrity Monitoring
Differential Corrections
Wide Area Augmentation System Provisions
Predictive RAIM
Airplane Personality Data Message (APDM)
Final Approach Segment (FAS) Data Message (FASDM)
Brief Description of the System
GNSS Sensor Functions
Control and Display Functions
Control and Display Unit (CDU) or Alternate Control Display Functions
GNSS Sensor
Antenna/Preamplifier/Filter
Interchangeability
Regulatory Approval
Reliability
Testability and Maintainability
Unit Identification
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
3
3
3
3
3
3
2.0
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.3
2.4
2.5
2.5.1
2.5.2
2.6
INTERCHANGEABILITY STANDARDS
Introduction
System Elements
2 MCU Configuration
Alternate Configuration
Control and Display
Antenna Form Factor
Data Loader
Standardized Signaling
Standard Interwiring
Power Circuitry
General
GNSS Sensor Power Circuitry
Environmental Conditions
4
4
4
4
4
4
4
4
4
4
4
4
4
5
3.0
3.1
3.2
3.3
3.3.1
3.4
3.4.1
3.4.2
GNSS SENSOR SYSTEM DESIGN
General
System Application
General System Capabilities
Differential GPS Capabilities
Specific System Capabilities
Acquisition Time
Degraded Performance
6
6
6
6
6
6
6
6
4.0
4.1
4.2
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.6.1
4.3.6.2
4.3.6.2.1
4.3.6.2.2
4.3.6.2.2.1
4.3.6.2.2.2
GNSS SENSOR DESIGN
Introduction
Integrity
Modes
Normal Acquisition
Abnormal Acquisition
Navigation
Altitude/Clock Aiding Mode
Aided Mode
Ground Based Augmentation System (GBAS)
SCAT I Mode
GBAS NAV
LAAS Excluding Precision Approach
LAAS Precision Approach
General Function Requirements
GLS with an External GNSSU
7
7
7
7
7
7
7
8
8
8
8
8
8
9
9
9
iii
ARINC CHARACTERISTIC 743A
TABLE OF CONTENTS
ITEM
4.3.6.2.2.2.1
4.3.6.2.2.2.2
4.3.7
4.3.8
4.3.8.1
4.3.8.1.1
4.3.8.1.2.1
4.3.9
4.3.10
4.3.11
4.4
4.4.1
4.4.1.1
4.4.1.2
4.4.1.3
4.4.1.4
4.4.1.5
4.4.1.6
4.4.2
4.4.2.1
4.4.2.2
4.4.2.3
4.4.3
4.4.4
4.4.4.1
4.4.5
4.4.5.1
4.4.5.2
4.5.
4.5.1
4.5.2
4.5.3
4.5.3.1
4.5.3.2
4.5.3.3
4.5.4
4.5.4.1
4.5.4.2
4.5.5
4.5.6
4.5.6.1
4.5.6.2
4.5.6.3
4.5.6.4
4.6
4.6.1
4.6.2
4.6.3
4.6.3.1
4.6.3.2
4.6.3.3
4.6.4
4.6.5
4.6.6
4.6.6.1
4.6.6.2
SUBJECT
GLS with a Precision Approach Navigation
(PAN) Function External to the GNSSU
GLS with a PAN Internal to the GNSSU
Differential GLONASS
Satellite Based Augmentation System (SBAS)
SBAS Nav
WAAS Precision Approach Mode
WAAS Precision Approach Mode Precision
Approach Navigator Functionality
Self Test Mode
Initialization Mode
Fault Mode
System Interfaces
Digital Data Inputs
Initialization Inputs
Inertial Inputs (ARINC Characteristics 704, 738 and 561
ADC Inputs
Magnetic Compass Input
Integrity Input
Differential Input
Digital Data Outputs
GNSS Measurement Block
SSM Operation
Navigation Data Block
Discrete Inputs
Discrete Outputs
Time Mark Output
Power
2 MCU Configuration Power
Alternate Configuration Power
Sensor Performance (2 MCU Configuration)
Acquisition Sensitivity (2 MCU Configuration)
Tracking Sensitivity (2 MCU Configuration)
In-Band Signal Rejection (2 MCU Configuration)
With Aeronautical Mobile Satellite Service (AMSS)
on Same Aircraft (2 MCU Configuration)
Without Aeronautical Mobile Satellite Service (AMSS)
on Same Aircraft (2 MCU Configuration)
Pulse Signal Rejection (2 MCU Configuration)
Signal Rejection (2 MCU Configuration)
Out-of-Band Continuous Wave (CW) Signal Rejection
(2 MCU Configuration)
Out-of Band Pulse Signal Rejection (2 MCU Configuration)
Burnout Protection (2 MCU Configuration)
Sensor RF Interface (2 MCU Configuration)
Connector (2 MCU Configuration)
Sensor Input Impedance (2 MCU Configuration)
Sensor Impedance and Stability (2 MCU Configuration)
Preamplifier Power (2 MCU Configuration)
Sensor Performance (Alternate Configuration)
Acquisition Sensitivity (Alternate Configuration)
Tracking Sensitivity (Alternate Configuration)
In-Band Signal Rejection (Alternate Configuration)
With Aeronautical Mobile Satellite Service (AMSS)
on Same Aircraft (Alternate Configuration)
Without Aeronautical Mobile Satellite Service (AMSS)
on Same Aircraft
Pulse Signal Rejection (Alternate Configuration)
Out-of-Band Signal Rejection (Alternate Configuration)
Burnout Protection (Alternate Configuration)
Sensor RF Interface (Alternate Configuration)
Connector (Alternate Configuration)
Sensor Input Impedance (Alternate Configuration)
iv
PAGE
9
9
9
9
9
9
9
9
9
9
9
10
10
10
10
10
10
10
10
10
10
11
11
11
11
11
11
11
11
11
12
12
12
12
12
12
12
13
13
13
13
13
13
13
13
13
13
13
14
14
14
14
14
14
14
14
ARINC CHARACTERISTIC 743A
TABLE OF CONTENTS
ITEM
SUBJECT
PAGE
4.6.6.3
4.7
Source Impedance and Stability (Alternate Configuration)
Location of the GNSS Function
14
14
5.0
5.1
5.2
5.2.1
5.2.2
5.2.3
5.2.4
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.4
5.4.1
5.4.2
5.4.3
5.4.4
5.4.5
5.4.6
5.4.7
5.5
5.5.1
5.5.2
5.5.3
5.5.4
5.6
INTEGRATED ANTENNA/PREAMPLIFIER/FILTER DESIGN
Introduction
Active Antenna Requirements (GPS Only)
Preamplifier Gain
Precipitation Static
Impedance and VSWR
Preamplifier Bias
Physical Characteristics (GPS Only)
Size, Weight and Connector
Installation
Coax Interface
Environmental Conditions
Antenna/Preamplifier/Filter Requirements (GPS/GLONASS)
Antenna/Preamplifier Carrier And Noise Requirements
Preamplifier Gain Compression
Preamplifier Selectivity
Impedance and VSWR
Preamplifier Stability
Burnout Protection
Preamplifier Bias
Physical Characteristics (GPS/GLONASS)
Size, Weight, and Connector
Installation
Coax Interface
Environmental Conditions
Reference Test Setup
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
16
16
16
16
16
16
16
16
16
16
6.0
6.1
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.4
PASSIVE ANTENNA DESIGN
Introduction
Antenna Performance Characteristics
Operating Frequency
Impedance and VSWR
Radiation Pattern, Polarization and Axial Ratio
Gain
DC Short Circuit
Precipitation Static
Physical Characteristics
Size, Weight, and Connector
Installation
Rain and De-icing Fluid Susceptibility
Environmental Conditions
Reference Test Setup
17
17
17
17
17
17
17
17
17
17
17
17
17
17
18
7.0
7.1
7.2
BITE
GNSS Sensor BITE
Purpose of the OMS
19
19
19
GNSS Sensor Unit Signal Input/Output Schematic
GNSS Sensor Unit, Alternate Configuration Diagram
GNSS Sensor Unit, 2 MCU Configuration
GNSS Sensor Unit, Alternate Configuration
ARINC 429 Input Data for GNSS
Notes for ARINC 429 Inputs
ARINC 429 Output Data for GNSS
ARINC 429 Label Definitions
Discrete ARINC 429 Input Definition for GNSS Sensor
ARINC 429 SSM Definition for GNSS Sensor
GPS 2 MCU Configuration Interference Level
20
21
22
25
27
28
29
33
40
41
44
ATTACHMENTS
1
2
3-1
3-2
4-1
4-1A
4-2
4-2A
4-3
4-4
5-1
v
ARINC CHARACTERISTIC 743A
TABLE OF CONTENTS
ITEM
5-2
5-3
5-4
5-5
6
7-1
7-2
8
9
10
SUBJECT
PAGE
In-Band and Near-Band Interference Environments
Antenna/Preamp Signal Rejection
GPS Alternate Configuration Interference Level
GPS/GLONASS Alternate Configuration Interference Level
Environmental Test Categories
GNSS Antenna Footprint
Antenna Evaluation Ground Plane
GNSS Time Mark
GNSS Signal Losses
Mode Transition Table
44
45
46
47
48
49
50
51
54
55
Differential Corrections
Satellite Based Augmentation System Provisions
Predictive RAIM Capability
Airplane Personality Data Message (APDM)
Final Approach Segment (FAS) Data Message (FASDM)
Glossary of Abbreviations and Acronyms
57
58
62
70
71
72
APPENDICES
A
B
C
D
E
F
vi
ARINC CHARACTERISTIC 743A - Page 1
1.0 INTRODUCTION
1.1 Purpose of This Document
This document set forth the characteristics of the
integrated Global Positioning System (GPS)/Global
Orbiting Navigation Satellite System (GLONASS) sensor
portion of a GNSS system intended for installation in
commercial aircraft. The intent of this document is to
provide general and specific design guidance for the
development of GNSS sensors for airline use. It describes
the desired operational capability of the GNSS system and
the standards necessary to ensure interchangeability.
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This Characteristic defines two stand alone device
configurations that may also be referenced by other
Characteristics which may provide a GNSS function
integrated within another device. For example ARINC
Characteristics 755, 756, and 760.
1.2 Summary of GNSS System Operational
Characteristics
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The GNSS system is intended to provide position,
velocity, and time (PVT) information for display to pilots,
Automatic Dependent Surveillance and use by other
aircraft systems, using:
GPS and GLONASS satellites
Only GPS satellites
Only GLONASS satellites
The selection or preference should be automatic or may
be alternately pilot selected or installation hardware
selected.
Differential techniques, applying correction to the
position determination based on ground-based
measurement, are being considered.
Carrier phase tracking, used in static ground
measurements, may be achieved for the dynamic
speed range of modern aircraft.
1.2.2 Integrity Monitoring
The use of GNSS position for navigation and for
Automatic Dependent Surveillance requires monitoring of
the system integrity, including satellites, with a maximum
time between significant failure and warning output as low
as 10 seconds. This may be achieved with external or
internal monitoring, or both. When possible, internal
monitoring, termed Receiver Autonomous Integrity
Monitoring (RAIM) should be used, however the GNSS
may be required to accommodate external monitoring
such as SBAS and GBAS augmentations.
1.2.3 Differential Corrections
The interface needed to support the RF data link is
described in Appendix A.
1.2.4 Wide Area Augmentation System Provisions
The interface needed to support the Wide Area
Augmentation system (WAAS) integrity and correction data
is described in Appendix B.
The interface needed to support predictive RAIM is
described in Appendix C.
COMMENTARY
COMMENTARY
In addition, satellite measurements may be
integrated with inertial data for integrity monitoring.
1.2.1
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1.2.5 Predictive RAIM
The GNSS system may utilize various augmentations to
enhance its operational capability.
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Predictive RAIM may be included within the aircraft
sensor unit to support TSO C-129 classes A1, A2, B1,
B2, C1, and C2.
Operational Consideration
1.2.6 Airplane Personality Data Message (APDM)
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When insufficient GPS and/or GLONASS satellites are
tracked to allow full processing, the receiver will accept
initialization of local position, time and date, but will not
output valid data.
The GNSS Sensor Unit is in full navigation mode when
four or more satellites are tracked. It then outputs
position, velocity, time and satellite range and range rate.
The fourth satellite may be replaced by the distance to the
earth center using the local earth model distance plus
pressure altitude, only when the available satellite
geometry does not provide four useable satellites and
pressure altitude has been calibrated to GPS altitude.
If a satellite signal is momentarily lost, for instance, in an
aircraft bank, dead reckoning may carry over until full
capability is restored.
COMMENTARY
Further development of the available technology is
expected to lead to improved accuracy.
Deleted by Supplement 4.
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1.2.7 Final Approach Segment (FAS) Data Message
(FASDM)
Deleted by Supplement 4.
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1.3 Brief Description of the System
The stand alone GNSS system may be in one of two
configurations. The first configuration (2 MCU) consists of
an antenna /preamplifier/ filter mounted on top of the
fuselage, the GNSS sensor located in the aircraft electronics
rack, and an associated Control and Display Unit (CDU) or
alternate means of control/display.
The alternate
configuration consists of a passive antenna mounted on top
of the fuselage, a GNSS sensor located inside the fuselage
typically within 10 feet of the antenna and an associated
CDU or alternate means of control/display. The GNSS
system provides position, velocity, and time outputs as well
as satellite position range and range rate (Doppler) data.
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ARINC CHARACTERISTIC 743A - Page 2
1.0 INTRODUCTION
1.3.1 GNSS Sensor Functions
The GNSS sensor uses RF signals from the
antenna/preamplifier (2 MCU configuration) or from the
passive antenna (the alternate configuration). It may utilize
ground speed or airspeed track angle and vertical speed and
altitude from other aircraft systems to compute and output
position, ground speed, track angle, altitude, vertical speed
and dilution of precision/figure of merit data as well as
perform integrity monitoring functions. The GNSS sensor
should, in addition to the autonomous GNSS navigation
information, output pseudo range, range rate, and satellite
position data which can be used by other navigation systems
to generate a hybrid GNSS solution.
The information defined in Attachments 4-2 and 4-3 should
be transmitted via an ARINC 429 high speed or low speed
bus. The data should exhibit the characteristics described in
ARINC Specification 429.
The GNSS sensor should also accept inputs of direction,
speed, altitude, and other information shown in Attachment
4-1 either on an ARINC 429 high speed or low speed bus.
COMMENTARY
The GNSS SU should be designed to operate with
GPS and GLONASS satellites. The sensor should
perform its navigation functions based on GPS,
GLONASS, or GPS and GLONASS satellites. The
selection or preference of one satellite system should
be automatic unless one of the systems is commanded
by the pilot or installation. The satellite systems being
used should be indicated on the ARINC 429 output.
The GNSS SU mode transitions (excluding off) should
be automatic and not require manual selection. The
GNSS sensor should provide the following modes of
operations:
OFF: The GNSS SU should be in off mode when power is
removed from all circuits (except for control circuits and
memory, etc.).
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ACQUISITION: The GNSS SU should be in acquisition
mode when insufficient GPS and/or GLONASS satellites
are tracked. In this mode the receiver should accept
initialization of user position, time (UTC), and date.
NAVIGATION: The GNSS SU should be in navigation
mode when four or more satellites with acceptable geometry
are in view and the system can adequately provide position,
velocity, time, pseudo range, and pseudo range rate outputs.
ALTITUDE/CLOCK AIDED: The GNSS SU should
provide a reversionary mode in such case that no acceptable
satellite constellation geometry exists to perform in
navigation mode. In this mode at least three satellites,
distance from the earth center (in an acceptable geometry)
and clock drift information are used for the navigation
computations and outputs. The earth center is considered a
pseudo-satellite, the distance to which is computed using
local earth radius and altitude. This mode is entered during
periods of adverse satellite geometry when an altitude input
is available.
AIDED: The aided mode is a short-term non-navigation
mode when one or more satellites, used in the navigation
computations, are temporarily unavailable such as during
aircraft maneuvering. In this case, altitude, direction, and
speed information should be used to “dead reckon” the
sensor solution and allow rapid reversion to the navigation
mode when conditions permit.
If navigation mode
conditions are not satisfied after a mode time limitation,
appropriate data status should be provided.
Optional submodes:
DIFFERENTIAL: A differential SBAS or GBAS mode
may be provided for where higher accuracy is achieved by
applying corrections to the satellite measurements based on
local area surveyed ground stations.
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1.3.2 Control and Display Functions
The GNSS sensor should be capable of accepting the
inserted/updated data (such as set latitude, longitude, UTC
time, date, etc.) via existing ARINC 429 input buses.
GNSS data (including satellite tracking status, geometric
dilution of precision, figure of merits, etc.) available on
existing output buses may be used for the display on
control/display devices.
1.3.3
Control and Display Unit (CDU) or Alternate
Control/Display Functions
These functions are in addition to those specified in related
ARINC Characteristics, e.g., 704, 738, 561, 702, 599, etc.
The CDU may include the following features:
a.
b.
c.
Satellite tracking status, dilution of precision and
figure or merit
A means to control GNSS functions
A means of updating and displaying: latitude,
longitude, altitude, direction, speed, UTC, time-ofday and date. The display device can also be used to
present other parameters, values and status of the
system upon selection.
1.3.4 GNSS Sensor
The GNSS sensor should use the L1 and C/A code
transmitted from GPS satellites and should use the fN
frequency PRN code transmitted from GLONASS satellites.
The sensor should perform RF processing, including down
conversion of the RF signal, correlation and loop tracking to
compute and output position, ground speed, track angle,
altitude and vertical speed to other aircraft systems.
COMMENTARY
The fN frequency is computed as:
fN = f1 + (N-1) -f; f1 - 1602. 5625 MHz
-f = 0. 5625 MHz
N - number of the GLONASS satellite
N = 1, 2, ... 24
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ARINC CHARACTERISTIC 743A - Page 3
1.0 INTRODUCTION
COMMENTARY
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GLONASS frequencies may change. This could impact
any section in this document that is frequency sensitive.
1.3.5 Antenna/Preamplifier/Filter
A single L-band antenna/preamplifier/filter mounted on top
of the fuselage, near the centerline, receives signals from the
GPS and GLONASS satellites, bandpass filters and
amplifies the resulting signal. The alternate configuration is
a passive antenna with the preamplifier/filter function
performed in the sensor. See Section 5 for details.
Losses associated with connectors and cables may be
eliminated by incorporating the preamplifier in the antenna
package. Design of the GNSS sensor should accommodate
a cable loss of 3 to 12 dB between antenna/preamplifier and
the sensor.
desires. Nevertheless, it is apparent that a trade-off of cost
versus reliability can be made for the system. It is for this
reason that the airlines want “lots” of reliability, but not so
much that costs become prohibitive.
COMMENTARY
A very high MTBF (e.g., greater than 40,000 flight
hours) is expected for the GNSS sensor(s) and
100,000 hours for the antenna/preamplifier.
1.7 Testability and Maintainability
Of equal economic importance with reliability is the Mean
Time Between Unscheduled Removals (MTBUR). The
GNSS designer should confer with the user to establish
goals and guidelines for testability to minimize unnecessary
removals. Similarly, the design of physical access and
functional partitioning of GNSS should minimize repair
time.
1.4 Interchangeability
1.8 Unit Identification
Interchangeability is desired between sensors with like form
factors, (i.e., 2 MCU units with other 2 MCU units and
Alternate Configuration with other Alternate Configuration
units). Once way interchangeability is also desired for
sensors built according to ARINC Characteristic 743 which
defined a GPS-only sensor. A GNSS sensor should operate
satisfactorily in an installation designed for a GPS-only
sensor.
COMMENTARY
ARINC Characteristic 743A was prepared in a manner
to promote as much commonality with ARINC
Characteristic 743 as possible. The goal was to
provide for the use of a GNSS Sensor in a GPS-only
installation.
Care was also taken to provide
interchangeability in the other direction (a GPS-only
sensor in a GNSS Sensor installation). The users
recognize that in this situation there will be no
GLONASS function available.
Interchangeability is desired between active antennas and
interchangeability is desired between passive antennas. No
provisions are expected for use of a passive antenna in an
installation designed for an active antenna or vice-versa.
1.5 Regulatory Approval
The GNSS equipment should meet all requirements of all
interested governments. This Characteristic does not and
cannot at present set forth the specific requirements that an
equipment manufacturer must follow to be assured of
airworthiness authorities approval.
However, some
considerations and guidelines for this design that may
facilitate the certification process are given in Section 3.0.
1.6 Reliability
The anticipated operational use of this system demands the
utmost attention to the need for reliability in all phases of
design, production, installation and operation of the GNSS
sensor. It is not the purpose of this Characteristic to define
specific MTBF requirements. It is expected that specific
reliability agreements will be negotiated between individual
airlines and GNSS manufacturers where the customer so
The GNSS Sensor should provide its equipment
identification number (00B) on its data output port as
defined in ARINC Specification 429. The GNSS Sensor
should also provide its software and hardware revision
level when requested by a centralized fault display unit on
the aircraft or when queried by ATE in the shop.
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ARINC CHARACTERISTIC 743A - Page 4
2.0 INTERCHANGEABILITY STANDARD
2.1 Introduction
This section of the Characteristic sets forth form factors,
interwiring, input and output interfaces, and power supply
characteristics desired for the GNSS. These standards
provide for the parallel but independent design of
compatible equipment and airframe installations.
Manufacturers should note that although this
Characteristic does not preclude the use of standards
different from those set forth herein, the practical
problems of redesigning a standard airframe installation to
accommodate a special equipment could very well make
the use of that equipment prohibitively expensive for the
customer.
Therefore, they should recognize the
advantages of developing equipment in accordance with
that set forth in this document.
2.2 System Elements
2.2.1 2 MCU Configuration
The 2 MCU configuration GNSS sensor should comply
with the dimensional standards in ARINC Specification
600, “Air Transport Avionics Equipment Interfaces for
the 2 MCU form factor.
Connector index pin coding for the 2 MCU is specified in
Attachment 3-1.
2.2.2 Alternate Configuration
The alternate configuration of the GNSS sensor should
comply with the form factor specified in Attachment 2.
2.2.3 Control and Display
The control and display function is shared with other
systems and described in other ARINC Characteristics,
e.g., 739, Multi-Purpose Control and Display Unit and
601, Control/Display Interfaces.
data signaling should conform to the standards set forth in
ARINC Specification 429, “Mark 33 Digital Information
Transfer System (DITS).” A description of the input and
output data blocks needed to ensure the desired level of
interchangeability as set forth in Attachments 4-1, 4-2,
and 4-3 of this document. Discrete time mark signals
should be as defined in Attachment 8 of this
Characteristic.
2.4 Standard Interwiring
The standard interwiring to be installed for the GNSS SU
is set forth in Attachment 3-1. This interwiring is
designed to provide the degree of interchangeability
specified in Section 1.4, and manufacturers are cautioned
not to rely upon special wires, cabling, or shielding for
use with particular units because they will not exist in the
standard installation.
COMMENTARY
Why Standardize Interwiring?
The standard interwiring is perhaps the heart of all
ARINC Characteristics. It is this feature which
allows the airlines customer to complete his
negotiations with the airframe manufacturer so that
the latter can proceed with engineering and initial
fabrication prior to airline commitment on a specific
source of equipment. This provides the equipment
manufacturer with many valuable months in which to
put the final “polish” on his equipment in
development.
The reader’s attention is directed to the interwiring
guidance in ARINC Report 414, Section 5.0. This
material defines all of the basic standards utilized in
airframe wiring installations and all equipment
manufacturers should make themselves familiar with
it.
2.5 Power Circuitry
2.2.4 Antenna Form Factor
2.5.1 General
For the 2 MCU and alternate configuration, the antenna
footprint shown in Attachment 7-1 should be used.
2.2.5 Data Loader
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The GNSS SU should be compatible with a data loader
unit defined by ARINC Report 615. The input to the
GNSS SU should be through the use of the pins
designated in Attachments 3-1 and 3-2 Standard
Interwiring of this Characteristic. The output from the
GNSS SU to the data loader should be from any of the
three ARINC 429 data output ports specified in the
Standard Interwiring. The communication with the data
loader should be activated by the assigned discrete input
pin.
2.3 Standardized Signaling
The standard electrical signaling between the GNSS
sensor and other airplane systems should be in digital
format. Standards should be established exactly to assure
interchangeability of equipment.
The standards
established herein are applicable to the signaling between
the GNSS sensor and other airplane systems. The serial
The aircraft power supply characteristics utilization
equipment design limitations and general guidance
material are set forth in ARINC Report 413A, “Guidance
for Aircraft Electrical Power Utilization and Transient
Protection.” Test conditions are contained in RTCA DO160/EUROCAE ED-14 (latest version). “Environmental
Conditions and Test Procedures for Airborne Electronic
Electrical Equipment and instruments.” In general, the
power circuitry interchangeability standards and
guidelines set forth in ARINC Standards apply to the
GNSS sensor.
2.5.2 GNSS Sensor Power Circuitry
The GNSS sensor should be designed to use no more than
40 watts during warm-up and not more than 25 watts
during normal operation. The “ON/OFF” control for the
GNSS sensor power input should be provided through a
circuit breaker(s) accessible to the flight crew. The rackmounted 2 MCU GNSS sensor configuration should be
provided with 115 Vac/400 Hz or 28 Vdc power. The
alternate GNSS configuration should be powered with 28
Vdc.
ARINC CHARACTERISTIC 743A - Page 5
2.0 INTERCHANGEABILITY STANDARD
2.6 Environmental Conditions
The GNSS sensor should be specified environmentally in
terms of the requirements of RTCA Document DO-160
and EUROCAE ED-14 (latest version). Attachment 6 to
this Characteristic tabulates the relevant environmental
categories.
ARINC CHARACTERISTIC 743A - Page 6
3.0 GNSS SENSOR SYSTEM DESIGN
GNSS sensor should be capable of accepting and using
this externally provided augmentation data.
3.1 General
This section describes the basic concepts underlying the
design of the GNSS system and its relationship to other
electronic systems in the aircraft. This section will, in
general, be limited to a discussion of system capabilities
which appear necessary to accomplish the functions set
forth in Section 1.3. More detailed hardware discussions
are contained in subsequent sections.
3.2 System Application
The GNSS system is intended to provide highly accurate
worldwide navigation capability with a high degree of
integrity. The GNSS navigation information is intended
to supply aircraft three dimensional position, velocity,
track data, time, and other information to other
subsystems for use in that subsystem’s navigation,
guidance or performance computations.
COMMENTARY
1. Once GNSS integrity and confidence is
established, the sensor output could be used to
accomplish inertial alignment while in motion.
Inertial alignment completion during taxi would
eliminate the need to remain stationary during
align, eliminate dispatch delays due to motion
detection and reduce pilot data input errors.
2. A further extension of align-during-taxi could be
the future potential of align-in-air. In this case,
the attitude mode could be eliminated and the
restart of NAV in air could be implemented.
3. GNSS sensor data can provide independent
monitoring and position reporting via a suitable
data link.
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The following are two means currently identified or
planned for augmentation:
Satellite Based Augmentation System (SBAS)
Ground Based Augmentation System (GBAS)
Additionally, augmentation of GNSS may be
accomplished through integration with on-board inertial
systems. It is assumed that this integration will be
implemented outside of the GNSS sensor unit. Therefore, c-3
inertial augmentation is not included in this characteristic.
Certain aspects of this characteristic such as the outputting
of raw pseudorange and delta range measurements are
intended to support external integration with inertial data.
3.3.1 Differential GPS Capabilities
The differential GNSS capability can be provided via an
SBAS system as defined in RTCA DO-229 “Minimum
Operational Performance Standards for Global
Positioning System/Wide Area Augmentation System
Airborne Equipment” or a GBAS System as defined in
RTCA DO-253 “Minimum Operational Performance
Standards for GPS Local Area Augmentation System
Airborne Equipment.”
The GNSS function should apply GBAS corrections when
in the GBAS Nav Mode (reference Section 4.3.6.2 GBAS
Nav).
The GNSS function should apply SBAS
corrections when in the SBAS Nav Mode (see Section
4.3.8.1 SBAS Nav). The GNSS receiver should apply the
pseudo range corrections to its own pseudo range and SV
measurement data before outputting the data on the output
buses.
3.4 Specific System Capabilities
3.3 General System Capabilities
3.4.1 Acquisition Time
The system should process satellite range and range rate
measurements and may use information from other
aircraft systems to calculate and output three dimensional
positions and velocities. Additionally, the system should
provide information on the quality of the navigation
information and perform integrity monitoring functions
both on the signal-in-space and the system itself.
The GNSS sensor should output the navigation
information based on the best combination of GNSS
signals and information from other aircraft systems.
Altitude, direction and speed information from other
aircraft systems should enable the GNSS system to
operate through geometry outages and masked satellite
coverage.
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Augmentation is the utilization of external data to
augment the airborne determination of satellite navigation.
This external data can be used to improve the accuracy of
navigation solution and to improve the integrity of
determining the health of the satellites used in the
navigation solution. This augmentation improves the
availability of GNSS navigation during periods with
limited satellite visibility and when navigation accuracy is
not sufficient to support the intended flight operation. The
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With latitude and longitude initialized within 100 km,
time initialized within 1 minute, with valid almanac data
and unobstructed satellite visibility, the time from
application of power to first valid position estimate should
be less than 3.5 minutes (95% confidence level). Without
valid initialization this time should be less than 10
minutes.
3.4.2 Degraded Performance
The system should annunciate internal failures,
degradation of the signal-in-space beyond specified limits,
etc., by modifying the contents of the output data words
supplied to the pilot’s instruments and other aircraft
systems in the manner described in ARINC Specification
429, “Mark 33 Digital Information Transfer System
(DITS).”
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ARINC CHARACTERISTIC 743A - Page 7
4.0 GNSS SENSOR DESIGN
COMMENTARY
4.1 Introduction
This section provides guidelines for design of the GNSS
Sensor Unit. Integrity monitoring, sensor inputs and
outputs, and performance specifications are addressed.
COMMENTARY
The airlines have expressed a desire to utilize the
accuracy of GNSS to substantially improve non-radar
airspace procedures and busy terminal capacity, and
possibly also airport surveillance and guidance. The
manufacturers should be aware that more than what is
presently included in this Characteristic should be
offered, if that “more” contributes to such airspace
operational improvement.
This relative independence of GNSS functional
modes and MMR GLS GBAS modes is necessary to
preserve similarities to existing procedures. For
example, if an airplane were navigating enroute with
SBAS, the pilot may choose to tune a GLS GBAS
approach before the airplane is within the radio range
of the GBAS ground station. In this case the GNSS
function (inside or outside the MMR) should continue
to operate in the SBAS mode even though the
commanded MMR mode is GLS. The GNSS function
should not transition to the GBAS mode until
differential corrections are actually available and
validated.
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4.3.1 Normal Acquisition
For example, the use of differential techniques, use of
the GNSS data link capability, carrier phase tracking
and developing standards for integrity monitoring
should be considered and capabilities should be
included, or, if not fully defined, provisions should be
made for a later inclusion.
4.2 Integrity
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The GNSS sensor should perform integrity monitoring of
itself and of the GNSS signal-in-space. See Section
4.4.2.2 for the method used to encode the results of
integrity monitoring. The designer should adhere to the
applicable RTCA Documents (DO-208, DO-229) for
alarm limits and warning response time.
To acquire signal from the GPS and GLONASS satellites,
the sensor uses: (1) almanac data which describes the
satellite motion, (2) time which, in conjunction with
almanac data, is used to determine the present position of
satellites, and (3) the approximate location of the sensor so
a determination can be made as to which satellites are
visible.
The GNSS sensor should store almanac data in non-volatile
memory which does not require internal or external battery
for support. When power is applied to the sensor, other
aircraft systems may provide initialization data. The sensor
determines which satellites are visible and acquires the c-3
satellite downlink data message, sets the SSM to the
appropriate status mode, enters the navigation mode and
reflects the appropriate integrity level.
4.3 Modes
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The GNSS function operates in one of 10 modes. Some
modes are associated with optional functionality, which
may therefore not be supported in all sensor units, or by
all GNSS functions embedded in other equipment such as
an Multi-Mode Receiver (MMR) or GNSS Navigation
and Landing unit (GNLU). The active GNSS function
mode will be annunciated via bits 24-28 of label 273.
Table 4.3-1 lists the GNSSU modes and specifies the bit
patterns to be used in label 273 for each mode.
The GNSS function chooses the mode of operation
automatically according to a pre-programmed precedence
of modes and the existence of particular conditions.
Attachment 10 includes a table which describes the mode
transitions and lists the conditions which stimulate mode
transitions. These conditions may include the existence of
Satellite Based Augmentation System (SBAS) or Ground
Based Area Augmentation System (GBAS) differential
corrections. The precedence of GNSS functional modes is
designed such that the GNSS function will provide the
best available accuracy and integrity at all times.
If a GNSS function is embedded within an Multi-Mode
receiver (MMR), the GNSS functional modes should
operate in a complementary but independent fashion
relative to the MMR modes. For example, if the MMR
mode is GNSS Landing System (GLS) precision approach
using GBAS, the GNSS function should not transition to a
local differential mode until local differential corrections
are actually available and validated.
When the GNSS function is in the Acquisition mode, the c-3
SSMs of all labels should be set as indicated in Attachment
4-4.
4.3.2 Abnormal Acquisition
If the sensor cannot conduct a normal acquisition, it should
initiate a “Search the Skies” acquisition. The sensor
attempts to acquire any available satellite without regard to
time or true position. When a satellite is acquired, c-3
ephemeris data is decoded from the satellite downlink
message. After sufficient satellites have been acquired, the
sensor should enter the navigation mode and reflect the
appropriate integrity level. The SSM should be set to the
appropriate status mode.
4.3.3 Navigation
The GNSS function enters the navigation mode from the
acquisition mode when sufficient satellite measurements
are available to perform a position solution calculation.
The navigation mode may also be entered from any SBAS
or GBAS mode if the SBAS or GBAS augmentations are
lost such that only an autonomous position solution is
possible. In the navigation mode pseudorange and range
rate are measured to determine and output position,
velocity and time (PVT). The basic PVT data is provided
in labels 110, 111, 112, 120, 121, 125, 150, 166, 174,
076,
and
370.
The
figure
of
merit
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ARINC CHARACTERISTIC 743A - Page 8
4.0 GNSS SENSOR DESIGN
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4.3.3 Navigation (cont'd)
data should continue to be output as valid data.
Attachment 4-4 for details.
(FOM) provided in labels 136 and 247 should provide an
estimate of the 95% position accuracy of the position
output.
While in the Aided Mode, the SSMs of all labels should be c-3
set as indicated in Attachment 4-4.
In the Navigation mode, Horizontal Integrity Limit (HIL)
and Vertical Integrity Limit (VIL) are based on the
Receiver Autonomous Integrity Monitoring (RAIM)
calculation.
See
4.3.6 Ground Based Augmentation System (GBAS)
4.3.6.1 SCAT I Mode
Deleted by Supplement 4.
COMMENTARY
4.3.6.2. GBAS Nav
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In order to take advantage of the removal of Selective
Availability (SA), the GNSS position solution may
estimate the accuracy of each measurement based on
the User Range Accuracy (URA) parameter provided
in the navigation message. It is recommended that
this be reflected in the URA output in label 057 of the
SV measurement data.
Optionally, the GNSS function may incorporate altitude
aiding, by using an externally derived altitude (e.g.,
pressure altitude, baro-corrected altitude), and/or onboard
clock aiding to aid the navigation solution or increase the
availability of RAIM and Fault Detection and Exclusion
(FDE) during intervals of adverse satellite coverage and
geometry.
As an option, the GNSS function should support
differential operations using GBAS corrections. In this
case, the GNSS function will enter the GBAS NAV mode
from the Navigation or SBAS Nav modes whenever
differential corrections messages are available and
validated. GBAS Differential corrections may be received
via the Differential input over the ARINC 429 port. The
protocols used to transfer differential corrections from an
external data link receiver to a GNSSU are detailed in
Appendix A. It is assumed that local differential
corrections from any nearby ground station will provide
better accuracy and integrity than the SBAS signals.
Therefore, unless the SBAS Nav is explicitly requested,
the GNSS function should give the GBAS Nav mode
precedence over SBAS Nav based on proximity to the
ground station.
COMMENTARY
COMMENTARY
4.3.4 Altitude/Clock Aiding Mode
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Many early GPS receivers use an independently
derived altitude to compute a navigation solution
when only three satellites are available. Modern
GNSS receivers incorporate altitude measurements,
during intervals where four or more healthy satellites
are in use, to improve the availability and
performance of the RAIM/FDE algorithm.
For a GNSS function within the MMR, when the
GNSSU receiver is the Data Broadcast Mode and a
specific GBAS approach has been selected, the
GNSS receiver should use differential correction
from the selected GBAS ground station (once the
correction have been validated by the MMR).
The GNSS function should annunciate the Altitude/Clock
Aiding mode, in bits 24-28 of label 273, whenever either
of these augmentations are used to compute position,
velocity, time, or autonomous integrity parameters. The
values contained within and the SSMs of the following
labels should be updated to properly reflect the level of
performance provided by this mode of operation: label
101- Horizontal Dilution of Precision (HDOP), 102Vertical Dilution of Precision (VDOP), 130-Autonomous
Horizontal Integrity Limit (HIL), 133-Autonomous
Vertical Integrity Limit (VIL), 136-Vertical Figure of
Merit (FOM), 247- Horizontal FOM.
In the GBAS NAV mode, the GNSS function should
apply the differential corrections received and monitor the
uplink messages for information relative to the integrity of
any satellite signals. The basic PVT data provided in
labels 110, 111, 112, 120, 121, 125, 150, 166, 174, 076,
and 370 should reflect the differential accuracy. The
GNSS function will compute a Horizontal Integrity Limit
(HIL) and Vertical Integrity Limit (VIL) based on
information contained in the data link messages, the
current satellite geometry and the receiver’s best estimate
of its own measurement accuracy. The receiver will also
perform fault detection by performing RAIM calculations
possibly using differentially corrected pseudoranges.
4.3.5 Aided Mode
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During short periods of adverse satellite coverage,
geometry, or masking the sensor may apply external
direction and speed aiding to its navigation solution
computations. The Aided Mode may be entered from the
Navigation Mode if less than four satellites are tracked.
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Aided Mode is an optional mode. The PVT outputs,
including FOMs and integrity limits, should be set NCD
in the Aided Mode. Satellite Vehicle (SV) measurement
COMMENTARY
Addition of label 370 is necessary because label 076
is altitude referenced to Mean Sea Level (MSL). A
GLS approach will require height above the WGS-84
ellipsoid.
4.3.6.2.1 LAAS Excluding Precision Approach
Deleted by Supplement 4.
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ARINC CHARACTERISTIC 743A - Page 9
4.0 GNSS SENSOR DESIGN
4.3.6.2.2 LAAS Precision Approach
4.3.9 Self Test Mode
Deleted by Supplement 4.
The GNSS function should enter the self test mode after
power up or after a power outage of greater than 10
seconds. While in the Self Test mode, the SSMs of all
labels should be set as indicated in Attachment 4-4.
4.3.6.2.2.1 General Functional Requirements
Deleted by Supplement 4.
COMMENTARY
4.3.6.2.2.2 GLS with an External GNSSU
Deleted by Supplement 4.
4.3.6.2.2.2.1 GLS with a Precision Approach Navigation
(PAN) Function External to the GNSSU
Deleted by Supplement 4.
4.3.6.2.2.2.2 GLS with a PAN Internal to the GNSSU
Deleted by Supplement 4.
There is no standard method for user initiation of the
Self Test mode. User initiated self test mode can
optionally be implemented via the user-defined
maintenance labels 352, 354, and 356.
4.3.10 Initialization Mode
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The GNSS function should enter the initialization mode to
transition from the time when power is applied and the
function begins the acquisition process. This time may be
used to initialize internal parameters, collect initialization
data, compute satellite visibility lists, or initialize
hardware in preparation to begin the search and
acquisition of satellite signals.
4.3.7 Differential GLONASS
COMMENTARY
Deleted by Supplement 4.
4.3.8 Satellite Based Augmentation System (SBAS)
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4.3.8.1 SBAS Nav
As an option, the GNSSU should support differential
operations using SBAS corrections. The GNSS function
will enter the SBAS Nav mode from the Navigation mode
whenever a valid GBAS signal is received demodulated
and validated and no GBAS corrections are available.
The GNSS function may also enter the SBAS Nav mode
from the GBAS Nav mode if the GBAS differential
corrections are lost. Once the SBAS signal is determined
to be valid, the GNSS function should apply the SBAS
differential corrections provided in the WAAS signal. The
basic PVT data provided in labels 110, 111, 112, 120,
121, 125, 150, 166, 174, 076, and 370 should reflect the
differential accuracy. The figure of merit (FOM) provided
in labels 136 and 247 and the SV measurement data in
labels 057, 061, 062, 063, and 064 should also reflect the
differential accuracy.
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The HIL and VIL should be computed based on
information contained in the SBAS messages and the
current satellite geometry. (Refer to RTCA DO-229
Appendix J.)
Table 4.3-1 GNSS MODES
Mode
#
Mode
1
2
3
4
5
6
7
8
9
10
Self Test
Initialization
Acquisition
Navigation
SBAS Nav
GBAS Nav
Alt/Clk Aiding
Reserved
Aided
Fault
Code (bits
28-24 of
label 273)
00000
00100
01000
01100
01101
01110
10000
10100
11000
11111
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4.3.11 Fault Mode
4.3.8.1.2.1 WAAS Precision Approach Mode Precision
Approach Navigator Functionality
The sensor may enter the fault mode from any other mode
if the Built In Test detects a critical sensor hardware fault
which adversely affects the navigation and time outputs.
While in the Fault mode the SSMs of all labels should be
set as indicated in Attachment 4-4. Fault annunciation is
also provided via a discrete signal as described in Section
4.4.4.
Deleted by Supplement 4.
4.4 System Interfaces
4.3.8.1.1 WAAS Precision Approach Mode
Deleted by Supplement 4.
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It is recognized that not all airborne equipment will
enunciate this state. It is possible that the unit will
transition from the initialization mode to the acquisition
mode prior to issuing the first label 273 with an
SSM=NORM. This scenario should not be interpreted
as faulty operation.
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ARINC CHARACTERISTIC 743A - Page 10
4.0 GNSS SENSOR DESIGN
4.4.1 Digital Data Inputs
4.4.1.6 Differential Input
ARINC 429 input ports should be provided as identified in
Attachment (4-1) to interface with FMCs, ADCs (ARINC
419 acceptable), MAG compasses, IRSs or other navigation
systems. The sensor should be able to determine which
information is pertinent to the specific installation required
for initialization, altitude, aiding, and dead-reckoning.
As an option, the GNSS SU should be capable of accepting
external differential corrections. The differential interface
may be high or low speed and should be configured to
automatically sense and adjust to the input speed.
4.4.1.1 Initialization Inputs
The GNSS sensor should be capable of being initialized
using the following inputs.
a.
b.
c.
d.
e.
f.
Set Latitude (041)
Set Longitude (042)
Set Altitude (040)
UTC (150)
UTC (125)
Date (260)
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COMMENTARY
Two ARINC 429 input ports are needed for the
differential interface. The interface should support a
file-oriented ARINC 429 block transfer which does not
require any reply or handshake from the GNSS SU.
High speed operation is strongly recommended for the
differential interface. However, low speed operation
should be supported for compatibility with existing
airframe equipment designs.
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4.4.2 Digital Data Outputs
See Attachment 4-2.
4.4.1.2 Inertial Inputs (ARINC Characteristics 704, 738,
and 561)
The GNSS sensor should be capable of being initialized,
aided with altitude or provide dead-reckoning with the
following inputs:
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
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Latitude (310)
Longitude (311)
UTC (125)
UTC (150)
Date (260)
Inertial Altitude (361)
Ground Speed (312)
Track Angle (313)
Vertical Speed (365)
True Heading (314)
The GNSS function should output a measurement block,
which contains the following labels for each satellite
tracked: 060, 061, 062, 063, 064, 065, 066, 070, 071, 072,
073, and 074.
COMMENTARY
The measurement status should be indicated in label 060 as
defined in Attachment 4-2B.
a.
b.
4.4.2.2 SSM Operation
Pitch Angle (324)
Roll Angle (325)
The GNSS sensor could be capable of accepting the
information to facilitate altitude/clock aiding and deadreckoning utilizing the following data:
a.
b.
Altitude (203) (standard pressure)
TAS (210)
The Sign/Status Matrix (SSM) encoding is described in
ARINC Specification 429.
Attachment 4-4 provides a list to indicate the status of the
sensor using the two bits of the SSM coding. For example:
for label 150, a VALID status is indicated by NORM with
bits 31-30 encoded as 1 and 1. In the ACQUISITION
mode, NCD code should be used by placing bit values 0
and 1 in bits 31 and 30, respectively.
4.4.1.4 Magnetic Compass Input
a. Self-Test
Test is Being Executed
The GNSS sensor should be capable of accepting the
information to facilitate dead-reckoning.
b. Acquisition
Sensor unit is operating normally
but cannot track satellites.
a.
c. Valid Navigation
Position >16 NM
The GNSS solution is calculated,
but the satellite constellation and
altitude data do not allow
determination of the position to
within 16 NM (95%) - a function
of FOM and not integrity.
Mag Heading (320)
4.4.1.5 Integrity Input
Deleted by Supplement 4.
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To support one major hybrid (GPS/IRS) design, label
377 should be broadcast within 260 msec of the Time
Mark Pulse and subsequent to the last label at the
navigation block and measurement block, which ever
occurs last.
Furthermore, if more than eight
observables are provided in the measurement block,
only the first eight measurements will be used.
The GNSS sensor could also be capable of accepting
information for future implementation, using the following
inputs:
4.4.1.3 ADC Inputs
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4.4.2.1 GNSS Measurement Block
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ARINC CHARACTERISTIC 743A - Page 11
4.0 GNSS SENSOR DESIGN
d. Valid Navigation
Position <16 nmi
e.
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Device Fault
The GNSS solution is calculated
and the satellite constellation and
altitude data allow determination
of the position to within 16 nmi
(95%).
The internal BITE has determined
that this device is faulted.
This definition maximizes the use of the GPS signal and
allows integrity to be performed via RAIM, external
augmentation, or navigation validation using other certified
navigation sources. Additionally, this minimizes the
number of cases for SSM definition to those required by
other systems.
4.4.2.3 Navigation Data Block
The navigation block is defined as labels 273, 076, 101,
102, 103 110, 111, 112, 120, 121, 130, 133, 136, 165, 166,
174, 247, 260, 125, 140, 141, and 150. The navigation
block starts with the status label 273 and ends with
measurement time 140,141, and 150.
4.4.3 Discrete Inputs
The GNSS Sensor should provide open/ground input
discretes to allow the external programming for the
following operating modes.
4.4.4 Discrete Outputs
The GNSS sensor should provide fault annunciation via a
discrete signal when the BITE function detects a critical
sensor hardware fault which adversely affects the navigation
and time outputs. The output should be an open/ground
discrete capable of sinking 250 milliamps with the
following definition:
Ground - Fault
Open - Normal Operation
4.4.4.1 Time Mark Output
The GNSS sensor should provide three separately buffered
Time Mark output discretes to synchronize the GPS outputs
(specifically the UTC time functions). Each of the three
outputs should be capable of driving three receiving
devices. Each of the receiving devices should provide a
330 ohms load. The operation and characteristic of the
Time Mark discrete is defined in Attachment 8.
4.4.5 Power
The GNSS sensor will be available in two configurations.
Each configuration should consume less than 25 watts
during normal operation and 40 watts during initial warmup.
4.4.5.1 2 MCU Configuration Power
a.
High/Low Speed Output Selection
The GNSS sensor should operate on either 28 Vdc or 115
Vac 400 Hz power.
Open - High Speed ARINC 429
Ground - Low Speed ARINC 429
4.4.5.2 Alternate Configuration Power
b. ARINC 419/429 Air Data Input Selection
The GNSS sensor should operate on 28 Vdc.
Open - ARINC 429
Ground - ARINC 419
c.
4.5 Sensor Performance (2 MCU Configuration)
The sensor operates on the L1 GPS frequency (1575.42
MHz) using the C/A-code. The sensor optionally uses the
GLONASS signal and corresponding PRN codes.
Data Loader Discrete
Open - Normal
Ground - Data Loader Mode
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COMMENTARY
d. Air/Ground Discrete
The GNSS sensor may be used for more demanding
operations (e.g., precision approach) and therefore, may
need to comply with additional requirements.
Manufacturers are expected to be aware of existing and
emerging certification requirements.
Ground - Ground
Open - Air
e.
SDI
Bits 10 and 9 of the designated labels should be encoded as
SDI bits as shown in the table below:
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Bit 10
Pin 5
or MP5A
SDI #2
Bit 9
Pin 36
or MP5B
SDI #1
Device
Ident
Open (0)
Open (0)
Ground (1)
Ground (1)
Open (0)
Ground (1)
Open (0)
Ground (1)
Not Used
Unit 1 (L)
Unit 2 (R)
Unit 3 (C)
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4.5.1 Acquisition Sensitivity (2 MCU Configuration)
The sensor will acquire an input carrier level of -121 dBm
and a minimum input carrier-to-noise density ratio of 37
dBHz (see Attachment 9).
COMMENTARY
Initial acquisition and reacquisition of GPS signals
should be capable at interference levels 6 dB below
those levels specified for tracking.
ARINC CHARACTERISTIC 743A - Page 12
4.0 GNSS SENSOR DESIGN
4.5.2 Tracking Sensitivity (2 MCU Configuration)
Once a signal is acquired, the sensor will track an input
signal with minimum carrier level of -124 dbm and a
minimum input Carrier-to-Noise density ratio of 34 dBHz.
4.5.3 In-Band Signal Rejection (2 MCU Configuration)
Refer to Attachments 5-1 (from Antenna MOPS RTCA
DO-228 Figure 2-2) and 5-2 (from WAAS MOPS RTCA
DO-229 Figure C-2) for a plot of the interference level.
Attachment 5-2 is a plot of In-Band and Near-Band
interference levels (from WAAS MOPS RTCA DO-229
C.2.2) and can be described as follows:
0 ≤ Bwi ≤ 700 Hz:
700 < Bwi ≤ 10 kHz
10 kHz < Bwi ≤ 100 kHz
100 kHz <Bwi ≤ 1 MHz
1 MHz < Bwi ≤ 20 MHz
20 MHz < Bwi ≤ 30 MHz
30 MHz < Bwi ≤ 40 MHz
c-3
40 MHz < Bwi:
-120.5 dBm
-119.5 + 6 log10
(Bwi/1000) dBm
-113.5 + 3 log10
(Bwi/10
000)
dBm
-110.5 dBm
Linearly
increasing from
-110.5 dBm to
-97.5 dBm
Linearly
increasing from
-97.5 dBm to
-91.1 dBm
Linearly
increasing from
-91.1 dBm to
-89.5 dBm
-89.5 dBm*
*Interference levels will not exceed -110 dBm/MHz in the
frequency range of 1575.42 ± 10 MHz.
All levels are measured at the antenna port before the
preamplifier. These levels should be translated from the
antenna port to the sensor input to account for the LNA
and filter characteristics and cable losses, per Attachments
5-3 and 9.
COMMENTARY
These translated interfering signal power densities
add to already existing power generated by the LNA,
filter network and sky noise, per Attachment 9.
4.5.3.2
Without Aeronautical Mobile Satellite Service
(AMSS) on Same Aircraft (2 MCU
Configuration)
After steady state navigation has been established, the
GNSS sensor should track GPS signals at -121 dBm in the
presence of an in - band and near - band interfering signal
in the frequency range of 1575.42 MHz ± (Bwi/2) MHz
with Levels as follows:
a.
6 dB less than the levels described in Section 4.5.3
for class 1 equipment.
3 dB less than the levels described in Section 4.5.3
for class 2 equipment
b.
Equipment Classes are defined in the WAAS MOPS
Section 1.4.2.
4.5.3.3 Pulse Signal Rejection (2 MCU Configuration)
After steady state navigation has been established, the
GNSS sensor should track GPS signals at -121 dBm in the
presence of an in-band and near-band pulse interference
within the frequency ranges specified in Attachment 5-2
and Section 4.5.3 and with the following characteristics:
Peak Power
Pulse Width
Pulse Duty Cycle
≤ 20 dBm
= one msec for GPS only signals and
125 microseconds for GPS/WAAS
signals
= 10%
COMMENTARY
The WAAS MOPS RTCA DO-229 Change 1
specifies +20 dBm pulse at the antenna port output,
the antenna MOPS RTCA DO-228 does not specify
the output level of the preamplifier when subjected to
a +20 dBm pulse. Change 1 to RTCA DO-229 also
specifies +20 dBm of CW against input burn-out. The
pulse width in the WAAS MOPS in Table C-2 of
Appendix C is 125 microseconds for test with
GPS/WAAS signals. This has been reflected in the
requirement.
4.5.4 Signal Rejection (2 MCU Configuration)
4.5.4.1
Out-of-Band Continuous Wave (CW) Signal
Rejection (2 MCU Configuration)
With Aeronautical Mobile Satellite Service
(AMSS) on Same Aircraft (2 MCU
Configuration)
The sensor should meet its performance requirements in the
presence of a CW signal which does not exceed the levels
shown in Attachment 5-1. The levels in Attachment 5-1
should then be adjusted according to the preamplifier gain,
cable loss, and filter rejection as shown in Attachment 5-3.
The requirements should be met over the full range of net
gain specified in Section 5.2.1 with a GPS signal of -134.5
dBm at the preamplifier input.
After steady state navigation has been established, the
GNSS sensor should track GPS signals at -121 dBm in the
presence of an in- band interfering signal in the frequency
range of 1575.42 MHz ± (Bwi/2) MHz that is as high as the
levels described above in Section 4.5.3.
The sensor should meet its performance requirements when
multiple carriers exist in the SATCOM band (1626.5
-1660.5 MHz) that can generate intermodulation products
of 7th order or higher in the GNSS band (1560 -1617
MHz).
Initial acquisition of GPS signals should be possible
at interference levels 6 dB below those levels
specified for tracking.
4.5.3.1
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ARINC CHARACTERISTIC 743A - Page 13
4.0 GNSS SENSOR DESIGN
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The sensor operates on the L1 GPS frequency (1575.42 c-2
MHz) using the C/A code. The sensor optionally uses the
GLONASS signal and corresponding PRN codes.
4.5.4.2
4.6.1 Acquisition Sensitivity (Alternate Configuration)
Out of Band Pulse Signal Rejection (2 MCU
Configuration)
Out of band is considered to be frequencies outside of the
bandwidth of L1 ± 20 MHz.
After steady state navigation has been established, the
GNSS sensor should track GPS signals at -121 dBm in the
presence of an out of band pulse interference within the
frequency ranges specified in Attached 5-2 and Section
4.5.3 and with the following characteristics:
Peak Power
Pulse Width
Pulse Duty Cycle
= 30 dBm
= 1 msec for GPS only signals and 125
microseconds for GPS/WAAS
signals
= 10%
4.5.5 Burnout Protection (2 MCU Configuration)
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The sensor should withstand, without damage, a continuous
unmodulated carrier of 20 dBm at the sensor antenna port.
4.5.6.1 Sensor RF Interface (2 MCU Configuration)
The RF interface to the sensor is through a size 5 coaxial
socket in a shell size 1 ARINC 600 connector. The contact
should be designed to accommodate the GNSS transmitter
frequency range. See Attachment 3-1.
4.5.6.2 Sensor Input Impedance (2MCU Configuration)
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The sensor should present a nominal 50 ohms impedance
at the input to the RF connector. The maximum VSWR
seen looking into the inputs should be no worse than 2:1
over the operating frequency range of 1575.42 MHz
± 3.069 MHz, and no worse than 4:1 in the extension of
that spectrum to 1575.42 MHz ± 10 MHz.
4.5.6.3
Sensor Impedance
Configuration)
and
Stability (2
MCU
The impedance presented by the source should be 50 Ohms
nominal with a VSWR not to exceed 1.5:1 over the
frequency range of 1575.42 MHz ± 10 MHz. The sensor
should be unconditionally stable for any positive real value
of source impedance.
c-4
The sensor will acquire an input signal with a minimum
input carrier level of -136 dBm and a minimum input
Carrier-to-Noise density ratio of 40.7 dBHz (see
Attachment 8).
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4.6.2 Tracking Sensitivity (Alternate Configuration)
Once a signal is acquired, the sensor will track an input
signal with minimum carrier level of -139 dBm and a
minimum input Carrier-to-Noise density ratio of 37.7
dBHz.
4.6.3 In-Band Signal Rejection (Alternate Configuration)
Refer to Attachments 5-1 (from Antenna MOPS RTCA
DO-228 Figure 2-2) and 5-2 (from WAAS MOPS RTCA
DO-229 Figure C-2) for a plot of the interference level.
Attachment 5-2 is a plot of In-Band and Near-Band
interference levels (from WAAS MOPS RTCA DO-229
C.2.2) and is described as follows:
0 ≤ BWi ≤ 700 Hz:
700< BWi ≤ 10 kHz
4.5.6 Sensor RF Interface (2 MCU Configuration)
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4.6 Sensor Performance (Alternate Configuration)
The signal rejection envelope shown in Attachment 5-1
assumes 40 dB of isolation between the SATCOM and
GNSS antenna installations. This level of isolation may be
accomplished with a physical separation of no less than 105
inches (2.67 meters) between antennas.
10 kHz < BWi ≤ 100 kHz
100 kHz < BWi ≤ 1 MHz
1MHz < BWi ≤ 20 MHz
20 MHz < BWi ≤ 30 MHz
30 MHz < BWi ≤ 40 MHz
40 MHz < BWi:
-120.5 dBm
-119.5 + 6 log10
(BWi/1000) dBm
-113.5 + 3 log10
(BWi/10 000) dBm
-110.5 dBm
linearly
increasing
from -110.5 dBm to
-97.5 dBm
linearly
increasing
from -97.5 dBm to
-91.1 dBm
linearly
increasing
from -91.1 dBm to
-84.5 dBm
-89.5 dBm*
*Interference levels should not exceed -110 dBm/MHz in
the frequency range of 1575.42 +/- 10 MHz.
All levels are measured at the antenna port. These levels
should be translated from the antenna port to the sensor
input to account for the cable losses, per Attachment 9.
COMMENTARY
4.5.6.4 Preamplifier Power (2 MCU Configuration)
These translated interfering signal power densities
add to already existing power generated by the sky
noise, per Attachment 9.
The GNSS sensor should provide 12 Vdc ± 20%, 100 mA
preamplifier power on the center conductor of the antenna
input to operate the remote antenna/preamplifier.
Initial acquisition of GPS signals should be possible
at interference levels 6 dB below those levels
specified for tracking.
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ARINC CHARACTERISTIC 743A - Page 14
4.0 GNSS SENSOR DESIGN
4.6.3 In-Band Signal Rejection (Alternate Configuration)
(cont'd)
COMMENTARY
The GNSS sensor may be used for more demanding
operations (e.g., precision approach) and therefore,
may need to comply with additional requirements.
Manufacturers should be aware of existing and
emerging certification requirements.
4.6.3.1 With Aeronautical Mobile Satellite Service (AMSS)
on Same Aircraft (Alternate Configuration)
The signal rejection envelope shown in Attachment 5-1
assumes 40 dB of isolation between the SATCOM and
GNSS antenna installations. This level of isolation may be
accomplished with a physical separation of no less than 105
inches (2.67 meters) between antennas.
c-3
4.6.5 Burnout Protection (Alternate Configuration)
The sensor should withstand without damage a continuous
unmodulated L1 carrier at 20 dBm.
4.6.6 Sensor RF Interface (Alternate Configuration)
4.6.6.1 Connector (Alternate Configuration)
After steady state navigation has been established, the
GNSS sensor should track GPS signal at -136 dBm in the
presence of an in-band interfering signal in the frequency
range of 1575.42 MHz ± (BWi/2) MHz that is as high as
the levels described above in Section 4.6.3.
4.6.3.2
Without Aeronautical Mobile Satellite Service
(AMSS) on Same Aircraft
After steady state navigation has been established, the
GNSS sensor should track GPS signals at -136 dBm in the
presence of an in-band and near-band interfering signal in
the frequency range of 1575.42 MHz ± (BWi/2) MHz with
levels as follows:
4.6.6.2 Sensor Input Impedance (Alternate
Configuration)
The sensor should present a nominal 50 ohm impedance at
the input to the RF connector. The maximum VSWR seen
looking into the input should be no worse than 2:1 over the
frequency range of 1575.42 ± 10 MHz.
4.6.6.3 Source Impedance
Configuration)
and
Stability
The impedance presented by the source should be 50 ohms
nominal with a VSWR not to exceed 1.5:1 over the
frequency range of 1575.42 ± 10 MHz. The sensor should
be unconditionally stable for any positive real value of
source impedance.
Equipment Classes are defined in the WAAS MOPS
Section 1.4.2.
4.7 Location of the GNSS Function
4.6.3.3 Pulse Signal Rejection (Alternate Configuration)
Deleted by Supplement 4.
After steady state navigation has been established, the
GNSS sensor should track GPS signals at -136 dBm in the
presence of an in-band and near-band pulse interference
within the frequency ranges specified in Attachment 5-2 and
Section 4.6.3 with the following characteristics:
Peak Power
Pulse Width
Pulse Duty Cycle
= +20 dBm
= 1 msec for GPS only signals and 125
microseconds for GPS/WAAS
signals
= 10%
4.6.4 Out-of-Band
Configuration)
Signal
Rejection
(Alternate
The sensor should meet its performance requirements in the
presence of a CW signal which does not exceed the levels
shown in Attachment 5-1. The level should then be
adjusted according to the cable loss with a GPS signal of
-134.5 dBm at the antenna port.
The sensor should meet its performance requirements when
multiple carriers exist in the SATCOM band (1626.5
-1660.5 MHz) that can generate intermodulation products
of 7th order or high in the GNSS band (1560 - 1617 MHz).
c-3
(Alternate
6 dB less than the levels described in Section 4.6.3 for
class 1 equipment.
b. 3 dB less than the levels described in Section 4.6.3 for
class 2 equipment.
a.
c-3
The RF interface to the sensor is through a single 50 ohm
female TNC type connector.
c-3
c-4
ARINC CHARACTERISTIC 743A - Page 15
5.0 INTEGRATED ANTENNA/PREAMPLIFIER/FILTER DESIGN
5.1 Introduction
c-3
c-4
This section describes the characteristic of the GNSS
antenna/preamplifier to be used with the 2 MCU form
factor configuration of the GNSS sensor.
The
characteristic intends to be compliant with RTCA DO228, “Minimum Operational Performance Standards for
Global Navigation Satellite System (GNSS) Airborne
Antenna Equipment” and TSO C-144.
sensor unit through a nominal 50 ohm double shielded
transmission line which should have a resulting gain as
shown in Attachment 9.
The antenna/preamplifier/filter assembly should be
installed to provide isolation from all L-band and VHF
antennas, in particular the SATCOM antennas, at the
GNSS and SATCOM operating frequencies, such that the
GPS sensor meets its performance requirements (see
Section 4.5.4.1).
5.2 Active Antenna Requirements (GPS Only)
COMMENTARY
The GNSS antenna should be compliant with the
minimum performance requirements specified in RTCA
DO-228, TSO C-144, and the following supplemental
characteristics.
5.2.1 Preamplifier Gain
c-3
The net gain delivered to the 2 MCU configuration in any
installation should be between 13.5 and 30 dB (refer to
Attachment 9). The range assumes an antenna gain, due
to the receiving element reception pattern of -4.5 dB.
COMMENTARY
c-4
Currently, two antenna types are commercially
available that are compliant to this characteristic. One
has a preamplifier gain specified at 29.5 dB
± 3 dB and the other is specified at 33 dB ± 3 dB.
These units are designed for cable and parasitic losses
of 3 dB to 12 dB and 6 dB to 15 dB, respectively.
5.2.2
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c-4
Impedance and VSWR
The VSWR presented by the antenna preamplifier to a
single 50 ohm transmission should not exceed 2:1 over the
frequency range of 1575.42 MHz ± 10 MHz .
5.2.4
c-4
5.3.3 Coax Interface
The interface between the antenna/preamplifier and the
GNSS sensor unit should be nominal 50 ohm coaxial
cable. See Attachment 9.
5.3.4
Environmental Conditions
The GPS antenna/preamplifier should be specified
environmentally in terms of the requirements of RTCA
DO-160C/EUROCAE ED-14C documents. Attachment 6
tabulates the relevant environmental categories.
Precipitation Static
The exposed antenna material should not be a detrimental
source of precipitation static discharge.
5.2.3
The isolation between a passive GPS antenna and all
L-band and VHF antennas should be a minimum of
40 dB when measured at the antenna connectors (see
Section 6.3.2). It is anticipated that the filter within
the active GPS antenna will provide additional
attenuation of interfering signals.
Preamplifier Bias
The preamplifier assembly should operate on 12 Vdc
(± 20%) at 100 mA (max) supplied on the center
conductor of the RF coaxial cable.
5.4 Antenna/Preamplifier/Filter
(GPS/GLONASS)
Requirements
The antenna assembly should be an integrated system than
will conform to the form factor shown in Attachment 7-1.
5.4.1
Antenna/Preamplifier
Requirements
Carrier
and
Noise
The carrier output of the assembly should not be less than
-108 dBm at a minimum carrier-to-noise density ratio of
37 dBHz (using a 100°K sky noise temperature at the
antenna input) when illuminated at 1575.42 MHz and at
(f1 ...f24 ) of GLONASS with a power density of -104.6
dBm/m2 at an elevation angle of five degrees or greater.
5.3 Physical Characteristics (GPS Only)
5.3.1
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c-4
Size, Weight, and Connector
5.4.2 Preamplifier Gain Compression
The antenna/preamplifier form factor should be as shown
in Attachment 7-1. A suitable sealing method should be
provided between the antenna and the aircraft skin.
Based on interference levels given in Attachment 5-2, the
preamplifier assembly should have a 3 dB margin from 1
dB gain compression.
The antenna connector should be type TNC female or
ARS as an alternate. The antenna assembly should weigh
less than one pound.
5.4.3 Preamplifier Selectivity
5.3.2 Installation
The preamplifier assembly should have the characteristics
given in Attachment 5-3.
The antenna assembly should provide electrical bonding
capability upon mounting to the aircraft. The DC bond
resistance of the bond should not exceed 1 milliohm. The
antenna should be connected to the associated GNSS
The signal rejection envelope shown in Attachment 5-3
takes into account a needed isolation of 40 dB between
the SATCOM antenna and the GNSS antenna in
accordance with Section 5.3.2.
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ARINC CHARACTERISTIC 743A - Page 16
5.0 INTEGRATED ANTENNA/PREAMPLIFIER/FILTER DESIGN
5.4.4 Impedance and VSWR
5.6 Reference Test Setup
The VSWR presented by the antenna preamplifier to a
single 50 ohm transmission line should not exceed 2: 1
over a frequency range of 6 MHz centered around L1
carrier frequency and a frequency range of 18 MHz
centered around the GLONASS central frequency 1609
MHz.
Antenna radiation pattern and gain measurements should
be made with the antenna mounted on four foot by seven
foot curved ground plane with the antenna mounted on
four foot by seven foot curved ground plane with a 96
inch radius of curvature (See Attachment 7-2). The
antenna tested should be illuminated with a right hand
circularly polarized wave with an axial ratio of less than
1.00 dB. For a gain reference, a NARDA 646 or
equivalent standard gain horn antenna should be used.
5.4.5 Preamplifier Stability
The preamplifier assembly should be unconditionally
stable for any source or load impedance.
5.4.6 Burnout Protection
The preamplifier burnout protection should withstand a
CW unmodulated input carrier of 30 dBm without
damage.
5.4.7 Preamplifier Bias
c-4
The preamplifier assembly should operate on 12 Vdc
(±20%) at 100 mA (max) supplied on the center
conductor of the RF coaxial cable.
c-4
5.5 Physical Characteristics (GPS/GLONASS)
5.5.1 Size, Weight, and Connector
The antenna/preamplifier form factor should be as set
forth in Attachment 7-1. A suitable sealing method
should be provided between the antenna and the aircraft
skin.
The antenna connector should be type TNC female or
ARS as an alternate. The antenna assembly should weigh
less than three pounds.
COMMENTARY
The preferred connector type is the TNC. However,
the availability of the TNC connector in Russia is
extremely limited. Therefore, the GPS Subcommittee
introduced the use of an ARS connector as an
alternate.
5.5.2 Installation
See Section 5.3.2
c-4
5.5.3 Coax Interface
See Section 5.3.3
5.5.4
Environmental Conditions
The GPS antenna/preamplifier should be specified
environmentally in terms of the requirements of RTCA
DO-160C/EUROCAE ED-14C documents. Attachment 6
tabulates the relevant environmental categories.
ARINC CHARACTERISTIC 743A - Page 17
6.0 PASSIVE ANTENNA DESIGN
6.1 Introduction
6.3 Physical Characteristics
This section describes the characteristics of the passive
GNSS antenna to be used with the Alternate Configuration
GNSS sensor units.
6.3.1 Size, Weight, and Connector
6.2 Antenna Performance Characteristics
6.2.1 Operating Frequency
The antenna should operate in a band of 4 MHz centered
around a carrier frequency (fo) of 1575.42 MHz (L1 carrier
(fo) Main Lobe Bandwidth = 2.046 MHz) and in a band of
14 MHz centered around a central frequency of 1609 MHz
(the frequency band of GLONASS).
6.2.2 Impedance and VSWR
The VSWR presented by the antenna to a single 50 ohm
transmission line should not exceed 1.5: 1 over a frequency
range of 1575.42 ± 3 MHz and 1609.0 ± 18 MHz when the
antenna is mounted at the center of a two feet by two feet
minimum ground plane.
6.2.3 Radiation Pattern, Polarization and Axial Ratio
The radiation pattern of the installed antenna should
provide omnidirectional upper hemispheric coverage and be
predominantly right hand circular polarized. The axial ratio
on boresight (i.e., zenith) should be less than 3.0 dB for all
frequencies of operations.
6.2.4 Gain
The antenna gain with the antenna installed in accordance
with the reference test setup (Section 6.3) should be as
follows:
a.
Elevation Angles greater than 15 degrees above the
horizon, the gain should be greater than minus 2.0
dBic.
b.
Ten degrees Elevation above the horizon, the gain
should be greater than or equal to minus 3.0 dBic.
c.
Five degrees Elevation above the horizon, the gain
should be greater than or equal to minus 4.5 dBic.
d.
On the horizon (0 degrees Elevation), the gain should
be between -7.5 dBic to -5.0 dBic.
e.
The gain variation in azimuth at any elevation angle of
five degrees or more above the horizon should be less
than 3.0 dB.
6.2.5 DC Short Circuit
The antenna should be designed to have a dc short circuit
(less than 0.05 ohms) when measured between the center
conductor of the output connector and the base.
6.2.6 Precipitation Static
The exposed antenna material should not be a detrimental
source of precipitation static discharge.
The antenna form factor should be as set forth in
Attachment 7-1. A sealing method should be provided
between the antenna and aircraft skin. The passive antenna
weight should not exceed two pounds. The antenna RF
output coaxial connector should be TNC female or ARS as
an alternate.
6.3.2 Installation
The antenna assembly should provide electrical bonding
capability upon mounting to the aircraft. The DC resistance
of the bond should not exceed one ohm. The antenna(s)
should be connected to its associated Remote Sensor Unit
through a nominal 50 ohm double shielded transmission
line which should have less than 1.5 dB attenuation at
operational frequency band.
The antenna should be installed to provide a minimum of 40
dB of isolation from all L band and VHF antennas, in
particular the SATCOM antennas, at the GNSS operating
frequencies measured at the antenna connector.
COMMENTARY
The antenna(s) should be located on the forward part of
the fuselage (on or close to the top centerline) to
minimize shadowing by the vertical stabilizer, wing
multi-path and shadowing by the wing during all
maneuvers.
Certain antenna installations require corrosion
protection in the form of a dielectric corrosion inhibitor
between the fuselage and the antenna baseplate. In this
situation the only bonding path is through the mounting
screws. In order to attain proper bonding, the antenna
mounting screw hole countersink must be such that the
installed screw head is in contact with the bare metal of
the baseplate.
6.3.3 Rain and De-icing Fluid Susceptibility
The antenna assembly should meet the following degraded
performance requirements when exposed to rain or ice (.050
inches accumulation) on the radome surface: the antenna
should have an average gain-loss no greater than 4.5 dB
from dry conditions when measured at an angle of 30 above
horizon. Under these conditions, the VSWR should not
exceed 2:1.
COMMENTARY
The antenna assembly should operate when residual
de-icing fluid is present upon the surface of the
radome.
6.3.4 Environmental Conditions
The GPS antenna should be specified environmentally in
terms of the requirements of RTCA DO-160C/EUROCAE
ED-14C documents. Attachment 6 tabulates the relevant
environmental categories.
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ARINC CHARACTERISTIC 743A - Page 18
6.0 PASSIVE ANTENNA DESIGN
6.4 Reference Test Setup
Antenna radiation pattern and gain measurements should be
made with the antenna mounted on four foot by seven foot
curved ground plane with a 96 inch radius of curvature
(Attachment 7-2). The antenna tested should be illuminated
with a right hand circularly polarized wave with an axial
ratio of less than 1.00 dB. For a gain reference, a NARDA
646 or equivalent standard gain horn antenna should be
used.
ARINC CHARACTERISTIC 743A - Page 19
7.0 BITE
7.1 GNSS Sensor BITE
The Sensor should contain Built-In Test Equipment
(BITE) capability in accordance with ARINC Report 624,
“Onboard Maintenance System (OMS).” To ensure the
sensor is capable of reporting faults in retrofit installations
which do not contain an OMS, the sensor should
optionally provide BITE capability in accordance with
ARINC Report 604, “Guidance for Design and Use of
Built-In Test Equipment (BITE).”
7.2 Purpose of the OMS
ARINC Report 624 sets forth a general philosophy, basic
guidance, and certain specific recommendations for the
design and use of an onboard maintenance system (OMS).
The OMS described incorporates the traditional areas of
failure monitoring and fault detection, BITE, BITE
access, and an airplane condition monitoring system
(ACMS), formerly known as aircraft integrated data
system (AIDS). It further describes the capability to
provide onboard maintenance documentation (OMD) and
the need for total integration of these functions. It
describes the needs for all elements of the OMS, including
a central maintenance computer (or CMC function) and
all the member systems which interface with it.
ARINC Report 624 is intended to provide a better mutual
understanding among the designers and users of the
specified OMS, including all its member systems, with a
view toward achieving an optimum balance between
critical factors such as BITE effectiveness, operator
interface simplicity, cost, and system complexity. A
description of one possible architecture for an OMS is
also included in the document. This description is not
intended to delineate the design for an OMS but to
provide an example for understanding the requirements
for such a system.
ARINC Report 624 discusses the role of an OMS in the
airlines’ maintenance concept and the fault detection and
BITE characteristics desirable in all avionics equipment to
support the broader goals of an OMS. Beyond the
guidance applicable to BITE, this document provides
specific guidance for the design of an OMS which
provides for:
a.
A standardized, English language-based user
interface for performing all BITE tests and line
maintenance functions on the airplane.
b.
Where appropriate, storage of BITE reported fault
data within a Line Replaceable Unit’s (LRU)
nonvolatile memory (NVM) for later use.
c.
Reporting of fault status in the air and on the ground
via operator displays and/or electronic/magnetic
communications links.
d.
Integration of the fault isolation design to provide
complete coverage, from fully automatic BITE
through interactive, BITE-assisted fault isolation to
manual troubleshooting procedures.
e.
Ground-test capability for fault isolation and
performance of LRU replacement tests, functional
tests, and system tests.
f.
OMD in both displayed and selectively printed
forms.
g.
Airplane condition monitoring function integrated
with the BITE/line maintenance function design.
Airframe and equipment designers are encouraged to take
advantage of this guidance information, beginning with
the earliest design phases of new equipment.
Users may also find this information helpful in
standardizing maintenance planning and procedures and
in securing appropriate recognition for such procedures
from the regulatory agencies. It is particularly important
that the guidelines set forth in ARINC Report 624 should
be considered in terms of the overall perspective of the
users’ needs, rather than some more limited objective.
(Note 2)
GPS/GLONASS SENSOR UNIT
2. Rack mounted for 2MCU config.
Overhead mounted for alternate config.
1. Filter/LNA integral of GPS/GLONASS
SU for alternate configuration.
NOTES:
IRS (429 HS)
or
FMS (429 LS)
IRS (429 HS)
or
FMS (429 LS)
TIMING DATA
GPS/GLONASS
DATA (429 HS/LS)
DIFFERENTIAL IN #2
DIFFERENTIAL IN #1
DADS/FMS (429/419 LS)
DADS/FMS (429/419 LS)
c-4
PROGRAM PINS
MAINTENANCE
INTERFACE
AIR/GROUND
FAULT DISCRETE
DATA LOADER
AIRCRAFT
POWER
FILTER/LNA
(Note 1)
ANTENNA
FUTURE USE
OPTIONAL DATA IN
DATA IN
TO USER SYSTEMS
ARINC CHARACTERISTIC 743A – Page 20
ATTACHMENT 1
GNSS SENSOR UNIT SIGNAL INPUT/OUTPUT SCHEMATIC
Length – 4
2
J1:M83723/92X204IN OR EQUIVALENT
Mates with: M83723/77R204IN
J2: TNC Female or ARS
.25" max
All dimension tolerances are ± .01"
ARINC CHARACTERISTIC 743A - Page 21
ATTACHMENT 2
GNSS SENSOR UNIT, ALTERNATE CONFIGURATION DIAGRAM
ARINC CHARACTERISTIC 743A - Page 22
ATTACHMENT 3-1
GNSS SENSOR UNIT, 2 MCU CONFIGURATION
A B C D
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
A B C D
A B C D
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
A B C D
Index Pin Code 04
1
2
3
4
5
GPS/GLONASS SENSOR
ARINC 600 CONNECTOR
REAR VIEW
ARINC CHARACTERISTIC 743A - Page 23
ATTACHMENT 3-1
GNSS SENSOR, 2 MCU CONFIGURATION
FUNCTION
c-4
c-1
STANDARD INTERWIRING
GNSS
Middle Insert
AIRCRAFT
429 OUT DATA #1 (A)
429 OUT DATA #1 (B)
TIME MARK OUT #1 (A)
TIME MARK OUT #1 (B)
01A
01B
01C
01D
To User Systems
To User Systems
To User Systems
To User Systems
429 IN IRS/FMS #1 (A)
429 IN IRS/FMS #1 (B)
429 IN DADS/FMS #1 (A)
429 IN DADS/FMS #1 (B)
02A
02B
02C
02D
From IRS/FMS
From IRS/FMS
From DADS
From DADS
429 IN DIFF #1 (A)
429 IN DIFF #1 (B)
429 IN DIFF #2 (A)
429 IN DIFF #2 (B)
03A
03B
03C
03D
From Differential Source
From Differential Source
From Differential Source
From Differential Source
GNSS SU FAULT
GNSS SU FAULT (RETURN)
429 HS/LS SELECT
INPUT DISCRETE RETURN
04A
04B
04C
04D
To User Systems
AC Ground
Program Pin
Program Pin Common
SDI INPUT #2
SDI INPUT #1
DADS 419/429 SELECT
SPARE
05A
05B
05C
05D
Program Pin
429 OUT DATA #2 (A)
429 OUT DATA #2 (B)
TIME MARK OUT #2 (A)
TIME MARK OUT #2 (B)
06A
06B
06C
06D
To User Systems
To User Systems
To User Systems
To User Systems
429 IN MAINTENANCE INTERFACE (A) (RSVD)
429 IN MAINTENANCE INTERFACE (B) (RSVD)
DATA LOADER MODE DISCRETE
AIR/GROUND DISCRETE
07A
07B
07C
07D
SPARE
SPARE
RESERVED FOR TEST
RESERVED FOR TEST
08A
08B
08C
08D
DATA LOADER IN (A)
DATA LOADER IN (B)
SPARE
SPARE
09A
09B
09C
09D
SPARE
SPARE
SPARE
SPARE
10A
10B
10C
10D
c-1
c-1
c-1
From Data Loader
From Data Loader
ARINC CHARACTERISTIC 743A - Page 24
ATTACHMENT 3-1
GNSS SENSOR, 2 MCU CONFIGURATION
FUNCTION
STANDARD INTERWIRING
GNSS
Middle Insert
AIRCRAFT
429 OUT DATA #3 (A)
429 OUT DATA #3 (B)
TIME MARK OUT #3 (A)
TIME MARK OUT #3 (B)
11A
11B
11C
11D
To User Systems
To User Systems
To User Systems
To User Systems
429 IN IRS/FMS #2 (A)
429 IN IRS/FMS #2 (B)
429 IN DADS/FMS #2 (A)
429 IN DADS/FMS #2 (B)
12A
12B
12C
12D
From IRS/FMS
From IRS/FMS
From DADS
From DADS
SPARE
SPARE
SPARE
SPARE
13A
13B
13C
13D
SPARE
SPARE
SPARE
SPARE
14A
14B
14C
14D
28 VOLTS (+)
28 VOLTS (+)
28 VOLTS (RETURN)
28 VOLTS (RETURN)
15A
15B
15C
15D
FUNCTION
RESERVED
CHASSIS GROUND
115 VOLTS AC *
115 VOLTS AC * (RETURN)
RF IN
GNSS
Bottom Insert
1
2
3
4
5
28Vdc Source
28Vdc Source
DC Ground
DC Ground
AIRCRAFT
DC Ground
115Vac Source
AC Ground
From Active Antenna
c-4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
PIN #
GPSSU SIGNAL
NAME
GNSS Fault
Reserved for Test
Reserved for Test
Data Loader In A
SDI 2
DADS/FMS In #1 A
DADS/FMS In #1 B
Input Discrete Return
Time Mark #2 A
DADS/FMS In #2 A
DADS/FMS In #2 B
Data Loader Mode Discrete
Time Mark #3 A
Time Mark #3 B
Data Loader In B
429 In Diff #2 A
429 In Diff #2 B
429 In IRS/FMC #1 A
Time Mark #1 H
Time Mark #1 L
429 HS/LS Select
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
PIN #
GPSSU SIGNAL
NAME
Time Mark #2 B
429 In Diff #1 A
429 Out #2 A
429 Out #2 B
429 In IRS/FMC#2 A
429 In IRS/FMC #2 B
Air/Ground Discrete
429 Out #3 A
429 Out #3 B
429 MAINT. INT.
429 In MAINT. INT.
Chassis Ground
+28 Volt Return
+28 Volt
SDI 1
429 In IRS/FMC #1 B
429 Out #1 A
429 Out #1 B
DADS 419/429 Select
429 In Diff #1 B
ARINC CHARACTERISTIC 743A – Page 1325
ATTACHMENT 3-2
GNSS SENSOR UNIT, ALTERNATE CONFIGURATION
c-4
ARINC CHARACTERISTIC 743A - Page 26
ATTACHMENT 3-2
GNSS SENSOR
ALTERNATE CONFIGURATION
FUNCTION
GNSS SU FAULT
RESERVED FOR TEST
RESERVED FOR TEST
DATA LOADER IN (A)
SDI 2
STANDARD INTERWIRING
GNSS Sensor
Connector J1
1
2
3
4
5
AIRCRAFT
To User Systems
From Data Loader
429 IN DADS/FMS #1 (A)
429 IN DADS/FMS #1 (B)
INPUT DISCRETE RETURN
TIME MARK OUT #2 (A)
429 IN DADS/FMS #2 (A)
6
7
8
9
10
Optional
Optional
Program Pin common
To User systems
Optional
429 IN DADS/FMS #2 (B)
DATA LOADER MODE DISCRETE
TIME MARK OUT #3 (A)
TIME MARK OUT #3 (B)
DATA LOADER IN (B)
11
12
13
14
15
Optional
To User Systems
To User Systems
From Data Loader
429 IN DIFF #2 (A)
429 IN DIFF #2 (B)
429 IN IRS/FMS #1 (A)
TIME MARK OUT #1 (A)
TIME MARK OUT #1 (B)
16
17
18
19
20
From Differential Source
From Differential Source
From IRS/FMS
To User Systems
To User Systems
429 HS/LS OUTPUT SELECT
TIME MARK OUT #2 (B)
429 IN DIFF #1 (A)
429 OUT DATA #2 (A)
429 OUT DATA #2 (B)
21
22
23
24
25
Program Pin
To User Systems
From Differential Source
To User Systems
To User Systems
429 IN IRS/FMS #2 (A)
429 IN IRS/FMS #2 (B)
AIR/GROUND DISCRETE
429 OUT DATA #3 (A)
429 OUT DATA #3 (B)
26
27
28
29
30
From IRS/FMS
From IRS/FMS
To User Systems
To User Systems
429 IN CMC (A)
429 IN CMC (B)
CHASSIS GROUND
28 VOLTS (RETURN)
28 VOLTS (+)
31
32
33
34
35
From CMC
From CMC
DC Ground
DC Ground
28 VDC Source
SDI 1
429 IN IRS/FMS #1 (B)
429 OUT DATA #1 (A)
429 OUT DATA #1 (B)
DADS 419/429 SELECT
36
37
38
39
40
From IRS/FMS
To User Systems
To User Systems
Program Pin
429 IN DIFF #1 (B)
41
From Differential Source
FUNCTION
ANTENNA RF IN
GNSS Sensor
Connector J2
1
AIRCRAFT
From Passive Antenna
c-4
c-4
ARINC CHARACTERISTIC 743A - Page 27
ATTACHMENT 4-1
ARINC 429 INPUT DATA FOR GNSS
Standard 429 labels:
OCT
LBL
429
PARAMETER
040
041
042
045
046
125
150
203
204
210
227
260
310
311
312
313
314
320
324
325
361
SET ALTITUDE
SET LATITUDE
SET LONGITUDE
MESSAGE BLOCK START
MESSAGE BLOCK DATA
UTC
UTC
ALTITUDE
BARO CORRECTED ALT
TRUE AIR SPEED
BITE COMMAND
DATE
LATITUDE
LONGITUDE
GROUND SPEED
TRACK ANGLE TRUE
TRUE HEADING
MAGNETIC HEADING
PITCH ANGLE
ROLL ANGLE
ALTITUDE (INERTIAL)
365
VERTICAL SPEED
INPUT
BUS
Note 4
4,5,6,7
4,5,6,7
4,5,6,7
2,3
2,3
4,5,6,7,8
4,5,6,7
4,5,6,7
4,5,6,7
4,5,6,7
8
4,5,6,7,8
4,5,6,7
4,5,6,7
4,5,6,7
4,5,6,7
4,5
4,5
4,5
4,5
4,5
4,5
SIGNAL
FORMAT
BCD
BCD
BCD
BCD
BNR
BNR
BNR
BNR
ISO #5
BCD
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
RANGE
SIG
BITS
FT
UP
79,999
DEG/MIN
N
±180°
DEG/MIN
E
±180°
N/A
N/A
N/A
N/A
N/A
N/A
HR:MIN
24:00.0
HR:MN:S
23:59:59
FT
UP
±131,072
FT
UP
±131,072
KNOTS
2,048
N/A
N/A
N/A
D:M:YR
N/A
DEGREE
N
±180°
DEGREE
E
±180°
KNOTS
4096
DEGREE CW-N ±180°
DEGREE CW-N ±180°
DEGREE CW-N ±180°
DEGREE
UP
±180°
DEGREE R-W-DN ±180°
FT
UP
±131,072
5
6
6
N/A
N/A
5
17
17
17
15
N/A
6
20
20
15
15
15
15
15
15
20
UNITS
FT/MIN
POS
SENSE
UP
±32,768
15
RES
1 FT
0.1 MIN
0.1 MIN
N/A
N/A
0.1 MIN
1.0 SEC
1.0 FT
1 FT
0.0625
N/A
1 DAY
0.000172
0.000172
0.125 KT
0.0055
0.0055
0.0055
0.0055
0.0055
0.125 FT
1.0
FT/MIN
MAX
TRANSMIT
INTERVAL
200 msec
200 msec
62.5 msec
62.5 msec
125 msec
120 msec
1200 msec
200 msec
200 msec
50 msec
50 msec
50 msec
50 msec
20 msec
20 msec
40 msec
NOTES
3
3
3
6
6
2
2
2
2
2
40 msec
c-4
ARINC 419 Inputs:
OCT
LBL
203
204
210
212
419
PARAMETER
ALTITUDE
BARO CORRECTED ALT
TRUE AIRSPEED
ALTITUDE RATE
INPUT
BUS
Note 4
SIGNAL
FORMAT
UNITS
6,7
6,7
6,7
6,7
BNR
BNR
BNR
BNR
FT
FT
KNOTS
FT/MIN
INPUT
BUS
Note 4
SIGNAL
FORMAT
UNITS
4,5,6,7
4,5,6,7
4,5,6,7
4,5,6,7
4,5,6,7
4,5,6,7
BNR
BNR
DISC
BNR
BNR
DISC
DEGREE
DEGREE
N/A
HR:MN
HR:MN
N/A
4,5,6,7
4,5,6,7
BNR
BNR
DEGREE
DEGREE
POS
SENSE
UP
UP
UP
RANGE
SIG
BITS
RES
MAX
TRANSMIT
INTERVAL
±131,071
±131,072
2,047
+20,480
17
17
11
10
1.0 FT
1 FT
1.0 KT
20 FT
62.5 msec
62.5 msec
500 msec
62.5 msec
RANGE
SIG
BITS
RES
MAX
TRANSMIT
INTERVAL
18
18
17
11
11
17
0.000687
0.000687
N/A
1 min
1 min
N/A
18
18
0.000687
0.000687
NOTES
2
Optional 429 labels:
OCT
LBL
429
PARAMETER
124
143
144
146
152
167
170
171
214
216
HORIZ INTEG. THRESHOLD
Dest Long
Dest Lat
SAT DESEL #1
Dest ETA
ALT WAYPT ETA
SAT DESEL #2
VERT. INTEG. THRESHOLD
ALT WAYPT LAT
ALT WAYPT LONG
POS
SENSE
RESERVED
E
±180°
N
±180°
N/A
N/A
23:59
23:59
N/A
N/A
RESERVED
N
±180°
E
±180°
NOTES
9
5,7,9
5,7,9
5,7,9
2,5,7,8,9
2,5,7,8,9
5,7,9
9
5,7,9
5,7,9
ARINC CHARACTERISTIC 743A - Page 28
ATTACHMENT 4-1
NOTES FOR ARINC 429 INPUTS
Notes:
[1]
Times in msec
[2]
Always positive
[3]
Burst of 2 per second for one second, or a 500 msec burst with each data word transmitted every 12 msec.
[4]
Bus #
Nomenclature
Pin #s (H/L) ALT
Pin #s (H/L) 2 MCU
1
2
3
4
5
6
7
8
Data Loader
Gen Purpose/Differential #1
Gen Purpose/Differential #2
IRS/FMS #1
IRS/FMS #2
DADS/FMS #1
DADS/FMS #2
OMS
04/15
23/41
16/17
18/37
26/27
06/07
10/11
31/32
09A/09B
03A/03B
03C/03D
02A/02B
12A/12B
02C/02D
12C/12D
07A/07B
c-2
c-4
[5]
Burst at a minimum rate of one second for up to three seconds or a 500 msec burst with each data word transmitted at
a maximum rate of 12 msec. If the FMS does not receive valid RAIM data from the GPS unit, it may retransmit the
burst.
[6]
The differential data word format is as shown in Appendix A of ARINC Characteristic 755.
[7]
Bits 10 and 9 of the designated data word should be encoded with SDI bits to which the predictive RAIM request is
directed (Ref: Appendix C).
Bit 10 Bit 9
SDI #2 SDI #1
c-2
c-4
0
0
1
1
0
1
0
1
Device
Ident
Not Used
Unit 1 (L)
Unit 2 (R)
Unit 3 (C)
[8]
Alternate Waypoint ETA and Destination ETA should be in UTC.
[9]
Reserved for optional implementation and not required. For GNSSUs with Predictive RAIM capability (see
Appendix C), labels 143, 144, 146, 152, 167, 170, 214, and 216 can be utilized.
ARINC CHARACTERISTIC 743A - Page 29
ATTACHMENT 4-2
ARINC 429 OUTPUT DATA FOR GNSS
Standard labels:
OCT
LBL
PARAMETER
060
061
062
063
064
065
066
070
071
072
073
074
076
101
102
103
110
111
112
120
121
125
130
133
136
140
141
150
165
166
174
226
247
260
273
355
370
377
Measurement Status
Pseudo Range
Pseudo Range Fine
Range Rate
Delta Range
SV Position X
SV Position X Fine
SV Position Y
SV Position Y Fine
SV Position Z
SV Position Z Fine
UTC Measure Time
GNSS Altitude (MSL)
HDOP
VDOP
GNSS Track Angle
GNSS Latitude
GNSS Longitude
GNSS Ground Speed
GNSS Latitude Fine
GNSS Longitude Fine
UTC
Aut Horiz Integ Limit
Aut Vert Integ Limit
Vertical Figure of Merit
UTC Fine
UTC Fine Fractions
UTC
Vertical Velocity
North/South Velocity
East/West Velocity
Data Loader Responses
Horizontal Figure of Merit
Date
GNSS Sensor Status
GNSS Fault Summary
GNSS Height
Equipment ID
SIGNAL
FORMAT
UNITS
PACK
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BCD
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
BNR
N/A
Meters
Meters
M/S
Meters
Meters
Meters
Meters
Meters
Meters
Meters
Seconds
Feet
N/A
N/A
Degrees
Degrees
Degrees
Knots
Degrees
Degrees
Hr:Min
NM
Feet
Feet
Seconds
Seconds
Hr:Min:S
Feet/Min
Knots
Knots
BNR
BCD
DIS
DIS
BNR
BCD
NM
Dy:Mo:Yr
N/A
Feet
N/A
POS
SENSE
N/A
+
+
+
ECEF
ECEF
ECEF
Up
CW-N
N
E
N
E
Up
N
E
N/A
Up
N/A
RANGE
SIG
BITS
N/A
N/A
±268, 435,456 20
256
11
±4096
20
±4096
20
±67, 108, 864 20
64
14
±67, 108, 864 20
64
14
±67, 108, 864 20
64
14
10.0
20
±131, 072
20
1024
15
1024
15
±108°
15
±108°
20
±108°
20
4096
15
0.000172°
11
0.000172°
11
23:59.9
5
16
17
32, 768
18
32, 768
18
1.0
20
0.9536, 743µs 10
23:59.59
17
±32, 768
15
±4096
15
±4096
15
Reserved
16
18
dd:mm:yr
6
N/A
N/A
21
±131, 072
20
N/A
N/A
MAX
TX
INTVL
[1]
N/A
1200
256
1200
0.125
1200
0.0039
1200
0.0039
1200
64
1200
0.0039
1200
64
1200
0.0039
1200
64
1200
0.0039
1200
9.536743µs
1200
0.125
1200
0.031
1200
0.031
1200
0.0055°
1200
0.000172°
1200
0.000172°
1200
0.125
1200
8.38 E-8°
1200
8.38 E-8°
1200
0.1 Min.
1200
1.2E-4
1200
0.125
1200
0.125
1200
0.953674µs
1200
0.9313225 ns 1200
1.0 sec
1200
1.0
1200
0.125
1200
0.125
1200
MAX
RES
[1]
6.1 E-5
1 Day
N/A
0.125
N/A
1200
1200
1200
1200
1200
1200
TRANSP
NOTES
DELAY
200
200
200
200
200
200
200
200
200
200
200
200
200
N/A
N/A
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
200
2, 5
2, 5
2, 4, 5
2, 5
2, 5
2, 5
2, 4, 5
2, 5
2, 4, 5
2, 5
2, 4, 5
2, 3, 5
200
200
N/A
N/A
200
N/A
3
3
3
3
3
3
3
3
3
4
4
3, 6
11
c-4
ARINC CHARACTERISTIC 743A - Page 30
ATTACHMENT 4-2
ARINC 429 OUTPUT DATA FOR GNSS
Optional labels:
OCT
LBL
PARAMETER
057 User Range Accuracy
c-4
124
126
127
143
144
155
156
157
162
163
237
343
344
346
347
352
354
356
Digital Time Mark
SAT Deselect #1
SAT Deselect #2
Approach Area HIL
Approach Area VIL
Counter
Maintenance (User Defined)
Maintenance (User Defined)
Destination ETA
Alt Waypoint ETA
Horizontal Uncertainty Level
Destination HIL
Destination VIL
Alt Waypoint VIL
Alt Waypoint HIL
Maintenance (User Defined) 1
Maintenance (User Defined) 2
Maintenance (User Defined) 3
SIGNAL
FORMAT
UNITS
BNR
Meters
DIS
DIS
DIS
Reserved
Reserved
DIS
DIS
BNR
BNR
BNR
BNR
Reserved
Reserved
BNR
DIS
DIS
DIS
POS
SENSE
RANGE
17 0.0625
Reserved
20
20
-
-
-
Reserved
Reserved
Hr:Min
Hr:Min
NM
NM
N/A
N/A
-
23:59
23:59
16
16
-
MAX
RES
[1]
8192
-
NM
Reserved
Reserved
Reserved
SIG
BITS
16
-
Reserved
11
1 Min.
11
1 Min.
17
.000122
11
0.0078
11
21
-
0.0078
-
MAX
TX TRANSP
NOTES
INTVL DELAY
[1]
2, 3, 5,
1200
200
10, 12
10
1200
N/A
10
1200
200
10
10
10
10
1200
200
10
1200
200
10
N/A
9, 10
N/A
9, 10
1200
200
1200
N/A
3, 10
10
10
N/A
3, 9, 10
1200
N/A
10
1200
N/A
10
1200
N/A
10
ARINC CHARACTERISTIC 743A - Page 31
ATTACHMENT 4-2
ARINC 429 OUTPUT DATA FOR GNSS
Notes
[1]
Time is in milliseconds. Nominal transmit interval is expected to be 1000 milliseconds.
[2]
Output rate per satellite. (The satellite measurement block should be output once per each tracked satellite. The
satellite measurement block should begin with measurement status and end with UTC measurement time. The
maximum number of satellite measurement blocks which can be transmitted in one second is 32.) The maximum
transport delay of the SV measurements are applicable to high speed outputs only.
[3]
Always Positive.
[4]
Fine data words contain the truncated portion of the original data word. This information is unsigned although the
sign bit is reserved. The two data words are concatenated (or combined) in the receiver.
[5]
The following information should be used in the generation of the SV raw data measurement block:
A. The measurement status should indicate the SVID, measurement validity, USER clock update, rate
measurement type and the C/No as defined in Attachment 4-3.
B. When not corrected within the differential mode, the pseudo range and pseudo range rate or delta range should
be corrected for the satellite clock, ionospheric and tropospheric errors (defined in ICD-GPS-200 and
GLONASS ICD).
C. The new pseudo range measurements include user clock bias errors which may accumulate over time such that
their values could overflow or underflow the data range. To avoid this condition, the GNSSU may adjust the
user clock error which would cause a step change to the pseudo ranges. Bit 19 of the status word (label 060) is
used to indicate to the using equipment of this condition so that proper adjustments can be made. Bit 19 should
be set 10 seconds before and after this update.
D. The integration time for the integrated delta range should be 1 second. The delta range measurement valid time
should be the time specified in Label 074 (end of integration period).
c-2
E. The ionospheric and tropospheric delay should be based on the ARINC 429 position input when the GPS
position cannot be determined.
F. A maximum of 16 measurement blocks can be transmitted for one measurement time.
G. The satellite position from each SV should be corrected by the GNSS Sensor for the rotation of the earth during
the time of the signal transmission to earth.
H. If differential corrections are being used, the raw data measurement block parameters should be corrected with
differential corrections. The method of correction should be based on the differential GNSS method being used.
J.
The number of GPS raw data measurement blocks corresponds to the number of satellites tracked. The number
of satellites used in the position solution is defined by Bits 20 to 23 of Label 273.
K. The User Range Accuracy (URA) data word contains the 2 sigma accuracy of the pseudo range measurement for
each satellite data block. The URA accuracy value may be obtained from three different sources as defined
below, depending on the mode of the GNSSU. Regardless of the mode, the value in the data word should
represent the best possible estimate of the pseudo range accuracy.
[6]
Bit 11 of label 150 should be encoded with a “1” when the GNSS system is being used as the source of time.
[7]
Bit 11 of label 130 should be set to “1” whenever the receiver’s RAIM detects a satellite failure and should be set to
“0” at all other times.
[8]
This output will be output at a nominal rate of 1 Hz and updated at a minimum of 0.2 Hz.
[9]
These outputs should be transmitted at a nominal rate of 1 Hz for each FMS input bus as a block of labels 162, 343,
or 163, 347. Transmissions for each FMS bus are separated by 0.5 second, nominal.
[10] Reserved for optional implementation and not required. For GNSSUs with Predictive RAIM capability (see
Appendix C), labels 126, 127, 143, 144, 162, 163, 343, 344, 346, and 347 can be utilized.
c-4
ARINC CHARACTERISTIC 743A - Page 32
ATTACHMENT 4-2
ARINC 429 OUTPUT DATA FOR GNSS
[11] The GNSS altitude data word (label 370) is the same as label 076, except the height above WGS-84 ellipsoid is
given. MSL conversion should adhere to ( data base and algorithms provided in ) Appendix 6 of NATO STANG
4294.
COMMENTARY
An ellipsoid is an ellipse rotated around its minor axis -- it can be easily defined mathematically. A geoid is a
(irregular) surface of equipotential gravity -- the WGS 84 (DOD World Geodetic System 1984) geoid is a first
order approximation of Mean Sea Level (MSL). The delta between the WGS 84 geoid and the WGS 84 ellipsoid
is called the geoidal undulation, and is defined by the Defense Mapping Agency as discrete points on a grid of the
earth (every x degrees lat and long) -- intermediate points can be interpolated. The WGS 84 geoid and ellipsoid
origins are both at the true center of the earth.
In most receivers, GPS positioning is performed in ECEF (xyz) Cartesian coordinates. These can be (iteratively)
transformed into ellipsoidal (geodetic) coordinates (latitude, longitude, altitude). At this point, altitude is
referenced to the ellipsoid -- a WGS 84 type look-up table is needed to convert it to a geoid (MSL) reference
(orthometric height system).
The North Atlantic Treaty Organization (NATO) Standardization Agreement (STANAG) 4294, Navstar Global
Positioning System (GPS) System Characteristics, Appendix 6, defines an algorithm to convert to MSL. A
database of adjusted geoid height values is provided for every 10 degrees latitude and longitude. Also, a
mathematical formulation is given to interpolate between these points. If all receiver manufacturers adhere to
this algorithm, differences between systems will be kept to a minimum.
[12] The URA label, 057, contains an estimate of the 2 sigma error of the pseudo range measurement for each satellite
data block. The URA value should represent the best possible estimate of the pseudo range accuracy. The URA
c-4
should account for all significant sources of error in the pseudo range measurement.
One acceptable method to estimate label 057 URA for unaugmented measurements is to double the result (to form a
two sigma value from one sigma data) of RSSing the following four terms:
1.
Satellite URA derived per paragraph 2.5.3 of the GPS SPS Signal Specification from the URA Index found
in bits 13 – 16 of word 3 in subframe 1 in the satellite nav data message.
2.
Standard deviation of the ionospheric correction residual errors calculated per DO-229B.
3.
Standard deviation of the receiver errors (e.g. errors due to multipath, thermal noise, smoothing filters,
code-carrier divergence, inter-channel biases) calculated per DO-229B.
4.
Standard deviation of the tropospheric model residual errors calculated per DO-229B.
One acceptable method to estimate label 057 URA for SBAS augmented measurements is to double the result of
RSSing the following four terms:
1.
Standard deviation of the Fast and Long Term Correction residual errors calculated per DO-229B.
2.
Standard deviation of the ionospheric correction residual errors calculated per DO-229B.
3.
Standard deviation of the receiver errors calculated per DO-229B.
4.
Standard deviation of the tropospheric model residual errors calculated per DO-229B.
One acceptable method to estimate label 057 URA for GBAS augmented measurements is to double the result of
RSSing the following three terms:
1. Standard deviation of the differential correction residual errors (σpr_gnd) as received in the Message Type 1
per DO-246A (or the type 1 message data in labels 045/046 from the VDB receiver.)
2. Standard deviation of the tropospheric correction residual errors calculated per DO-253.
3. Standard deviation of the receiver errors calculated per DO-253.
ARINC CHARACTERISTIC 743A - Page 33
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 060: Measurement Status
BIT
FUNCTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Label 1st Digit
0 0
0
Label 1st Digit
Label 2nd Digit
6 1
nd
1
Label 2 Digit
0
Label 2nd Digit
rd
Label 3 Digit
0 0
0
Label 3rd Digit
0
Label 3rd Digit
SDI
SDI
System
1 = GLONASS (Reserved)
C/NO
C/NO
C/NO
Range: 0-63 (00-3FHex)
C/NO
C/NO
C/NO
Satellite Position Data Used
1 = Ephemeris Data Used
User Clock Update
1 = Clock Update
Measurement Code Used
1 = P Code
Rate Measurement Type
1 = Delta Range Measurement
Range Rate or
1 = Valid
Delta Range Status
SVID Status/Isolation
1 = Valid
SVID (PRN Code No.)
SVID (PRN Code No.)
SVID (PRN Code No.)
Range: 0 to 63; (00Hex to 3FHex)
SVID (PRN Code No.)
SVID (PRN Code No.)
SVID (PRN Code No.)
SSM
SSM
Parity (odd)
23
24
25
26
27
28
29
30
31
32
CODING
NOTES
0 = GPS (Forced to 0)
[3]
c-3
0 = Almanac Data
0 = No Clock Update
0 = C/A Code
0 = Range Rate Measurement
0 = Invalid
0 = Invalid/Isolated
[2]
[1]
[4]
[4]
Notes:
[1] Bit 23 of Label 060 should be set to zero (invalid) when an erroneous satellite is isolated and removed from the
solution (due to malfunction or RAIM detection).
[2] Bit 21 indicates the type of rate measurement being provided by the receiver. If it is set to 0, label 063 provides a c-2
range rate measurement based on the Doppler for the dwell time at the receiver for that measurement. This is
typically provided by the non-continuous code tracking receivers. If it is set to 1, label 064 provides a delta range
measurement which is the integrated delta range over the last measurement interval.
[3] Bit 11 should be set to 0 when the value contained in SVID ID for a GPS satellite, and set to 1 when the value is for
a GLONASS satellite. The WAAS measurements will be denoted by setting Bit 11 to 0 and Mapping the WAAS
PRN codes 120-138 to SVID values 38-56, respectively.
COMMENTARY
Manipulation of the “Satellite Type” bit and values of SVID can be extended to include other Ssatellite-Based
Augmentation Systems (SBAS) as they become available (e.g., EGNOS, MTSAT, etc.).
[4] Sign Status Matrix (SSM)
BITS
31
30
0
0
0
1
1
0
1
1
MEANING
Normal Operation
No Computed Data
Functional Test
Not Used
c-3
ARINC CHARACTERISTIC 743A – - Page 34
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 124: Digital Time Mark (GPS [DISC]
c-4
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
SDI
SDI
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
PAD
SSM
SSM
Parity (Odd)
1
2
4
[1] Sign Status Matrix (SSM)
BITS
30
0
1
0
1
0
1
0
1
0
1
0
0
[1]
[1]
NOTES:
31
0
0
1
1
NOTES
MEANING
Normal Operation
No Computed Data
Functional Test
Fail Warning
ARINC CHARACTERISTIC 743A - Page 35
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 125: UTC [BCD]
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
SDI
SDI
0.1 Minutes
0.2
0.4
0.8
1.0 Minutes
2.0
4.0
8.0
10.0 Minutes
20.0
40.0
80.0
1.0 Hours
2.0
4.0
8.0
10.0 Hours
20.0
40.0
SSM
SSM
Parity (Odd)
1
2
5
[1]
[1]
[1] Sign Status Matrix (SSM)
BITS
30
0
1
0
1
0
1
0
1
0
1
0
1
c-3
NOTES:
31
0
0
1
1
NOTES
MEANING
Normal Operation (Plus)
No Computed Data
Functional Test
Not Used (Always Positive)
ARINC CHARACTERISTIC 743A – - Page 36
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 237: Horizontal Uncertainty Level [BNR]
c-4
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
SDI Code
SDI Code
RESERVED
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Integrity limit
Sign BIT
SSM
SSM
Parity (Odd)
2
3
7
[1]
[1]
[1] Sign Status Matrix (SSM), See Table
BITS
30
0
1
0
1
1
0
0
1
1
1
1
1
1 = 0.000122
LSB = 16*2-17
1 = 0.000244
1 = 0.000488
1 = 0.000977
1 = 0.001954
1 = 0.003907
1 = 0.007814
1 = 0.015629
1 = 0.031258
HIL = .000122 to 16 Nautical Miles
1 = 0.062515
1 = 0.12503
1 = 0.250061
1 = 0.500122
1 = 1.000243
1 = 2.000486
1 = 4.000973
1 = 8.001946
MSB = 16*2-1
Set to 0 (Always Positive)
NOTES:
31
0
0
1
1
NOTES
MEANING
Failure Warning
No Computed Data
Functional Test
Normal Operation
ARINC CHARACTERISTIC 743A - Page 37
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 273: Sensor Status [DISC]
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
SDI
SDI
MSB of Satellites Visible
DADC/FMS Source
DADC/FMS Source
IRS/FMS Source
IRS/FMS Source
Number of Satellites Visible
Number of Satellites Visible
Number of Satellites Visible
Number of Satellites Visible
Number of Satellites Tracked
Number of Satellites Tracked
Number of Satellites Tracked
Number of Satellites Tracked
GNSS Sensor Operational Mode
GNSS Sensor Operational Mode
GNSS Sensor Operational Mode
GNSS Sensor Operational Mode
GNSS Sensor Operational Mode
MSB of Satellites Tracked [1]
SSM
SSM
Parity (odd)
2
7
3
NOTES
1
0
1
1
1
0
1
1
1 = >15 Visible
0 = Present
0 = Primary
0 = Present
0 = Primary
0 = 15 or less Visible (forced)
1 = Not Present
1 = Secondary
1 = Not Present
1 = Secondary
c-3
= (0-Fhex)
= (0-Fhex)
[1]
[2]
1 = > 15 Tracked
0 = 15 or Less Tracked
[3]
[3]
Notes:
[1] The number of satellites tracked is the number of
satellites used for position/velocity/time parameters
determination.
[2] The bit assignments to these modes are not
incrementally assigned, to maintain backward
compatibility with ARINC Characteristic 743A-2.
Coding 111XX is always Fault (Ref: Note 4).
[3] Sign Status Matrix (SSM)
[4] GNSS Modes
BITS
31
30
0
0
0
1
1
0
1
1
MEANING
Normal Operation
No Computed Data
Functional Test
Not Used
Mode #
Mode
1
2
3
4
5
6
7
8
9
10
Self Test
Initialization
Acquisition
Navigation
SBAS, NAV
GBAS, NAV
Alt/Clk Aiding
Reserved
Aided
Fault
Code (bits 2824 of
label 273)
00000
00100
01000
01100
01101
01110
10000
10100
11000
11111
c-4
ARINC CHARACTERISTIC 743A – - Page 38
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 355: GNSS Sensor Fault Summary Format [DISC]
c-3
c-4
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
SDI
SDI
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved for IRS Bus #3 Status
AUX Data Broadcast #2 Bus Status
AUX Data Broadcast #1 Bus Status
DADS/FMS Bus #2 Status
DADS/FMS Bus #1 Status
IRS/FMS Bus #2 Status
IRS Bus/FMS #1 Status
GNSS System
GNSS RF Interface Status
GNSS Sensor Unit
Bite Test Inhibit
CFDS/CMC Command Wd Ack.
SSM
SSM
Parity (Odd)
c-3
NOTES:
[1] Sign Status Matrix (SSM)
BITS
31
0
0
1
1
30
0
1
0
1
MEANING
Normal Operation
No Computed Data
Functional Test
Failure Warning
3
5
5
NOTES
1
1
1
0
1
1
0
1
0 = Active
0 = Active
0 = Active
1 = No Activity
1 = No Activity
1 = No Activity
0 = Active
1 = No Activity
0 = Active
1 = No Activity
0 = Active
1 = No Activity
0 = Active
1 = No Activity
0 = Normal Op
1 = Failed
0 = Normal Op
1 = Failed
0 = Normal Op
1 = Failed
0 = Normal Op
1 = Test Inhibit
0 = Acknowledge 1 = No Acknowledge
[1]
[1]
ARINC CHARACTERISTIC 743A - Page 39
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 370: GNSS Height (WGS-84) [BNR]
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
0.125
0.25
0.5
1
2
4
8
16
32
64
128
Feet
256
512
1024
2048
4096
8192
16384
32768
65536
0 = Plus
SSM
SSM
Parity (Odd)
3
7
0
1 = -131,072 Feet
[1]
[1]
[1] Sign Status Matrix (SSM)
BITS
30
0
1
0
1
1
1
1
1
1
0
0
0
c-4
NOTES:
31
0
0
1
1
NOTES
MEANING
Failure Warning
No Computed Data
Functional Test
Normal Operation
ARINC CHARACTERISTIC 743A - Page 39
ATTACHMENT 4-2A
ARINC 429 LABEL DEFINITION
LABEL 370: GNSS Height (WGS-84) [BNR]
BIT
FUNCTION
CODING
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Label 1st Digit
Label 1st Digit
Label 2nd Digit
Label 2nd Digit
Label 2nd Digit
Label 3rd Digit
Label 3rd Digit
Label 3rd Digit
0.125
0.25
0.5
1
2
4
8
16
32
64
128
Feet
256
512
1024
2048
4096
8192
16384
32768
65536
0 = Plus
SSM
SSM
Parity (Odd)
3
7
0
1 = -131,072 Feet
[1]
[1]
[1] Sign Status Matrix (SSM)
BITS
30
0
1
0
1
1
1
1
1
1
0
0
0
c-4
NOTES:
31
0
0
1
1
NOTES
MEANING
Failure Warning
No Computed Data
Functional Test
Normal Operation
ARINC CHARACTERISTIC 743A - Page 40
ATTACHMENT 4-3
DISCRETE ARINC 429 INPUT DEFINITION
FOR GNSS SENSOR
c-2
(Deleted by Supplement 2)
ARINC CHARACTERISTIC 743A - Page 41
ATTACHMENT 4-4
ARINC 429 SSM DEFINITION FOR GNSS SENSOR
OCT.
LBL.
057
060
061
062
063
064
065
066
070
071
072
073
074
076
101
102
103
110
111
112
120
121
124
125
126
127
130
133
136
140
141
143
144
150
155
156
157
162
163
165
166
174
226
237
247
260
429 PARAMETER
SELF
TEST
USER RANGE ACCURACY
MEASUREMENT STATUS
PSEUDO RANGE
PSEUDO RANGE FINE
RANGE RATE
DELTA RANGE
SV POSITION X
SV POSITION X FINE
SV POSITION Y
SV POSITION Y FINE
SV POSITION Z
SV POSITION Z FINE
UTC MEASURE TIME
GPS ALTITUDE (MSL)
HDOP
VDOP
GPS TRACK ANGLE
GPS LATITUDE
GPS LONGITUDE
GPS GROUND SPEED
GPS LATITUDE FINE
GPS LONGITUDE FINE
DIGITAL TIME MARK
UTC
SAT DESEL #1
SAT DESEL #2
AUT. HORZ INTEG. LIMIT
[b]
AUT. VERT. INTEG. LIMIT
[b]
VERT. FIGURE OF MERIT
[b]
UTC FINE
UTC FINE FRACTIONS
APPROACH AREA HIL
APPROACH AREA VIL
UTC
COUNTER
MAINTENANCE
MAINTENANCE
DESTINATION ETA
[c]
ALT WAYPOINT ETA
[c]
VERTICAL VELOCITY
NORTH/SOUTH VELOCITY
EAST/WEST VELOCITY
DATA LOADER RESPONSES
HORIZONTAL UNCERTAINTY LEVEL
HORIZONTAL FOM
[b]
DATE
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
TEST
RESERVED
TEST
NORM
NORM
TEST
TEST
TEST
TEST
TEST
RESERVED
RESERVED
TEST
RESERVED
RESERVED
RESERVED
TEST
TEST
TEST
TEST
TEST
RESERVED
TEST
TEST
TEST
NCD
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
NCD
NCD
NCD
NCD
NCD
NCD
NCD
NCD
NCD
AIDED
(ALT/CLK
AIDING
NAV MODE
HFOM >16)
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NCD
NORM
NORM
NCD
NCD
NCD
NCD
NCD
NCD
(ALT/CLK
AIDING
NAV
MODE [a]
HFOM <16
NORM
NORM
NORM
NORM
NCD
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
FAIL
NORM
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
FAIL
NCD
NORM
NORM
NCD
NCD
NCD
NCD
NCD
NORM
NORM
NORM
NCD
NCD
NCD
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NORM
NCD
NORM
NORM
FAIL
FAIL
FAIL
FAIL
FAIL
INITIAL
ACQUISITION
MODE
FAULT
MODE
c-2
c-2
c-2
c-2
c-2
NCD
NORM
NORM
FAIL
c-2
NORM
NORM
NCD
NCD
NCD
NORM
NORM
NCD
NCD
NCD
NORM
NORM
NORM
NORM
NORM
FAIL
FAIL
FAIL
FAIL
FAIL
NCD
NCD
NCD
NCD
NCD
NORM
NORM
NORM
NORM
FAIL
FAIL
NCD
c-2
c-4
ARINC CHARACTERISTIC 743A - Page 42
ATTACHMENT 4-4
ARINC 429 SSM DEFINITION FOR GNSS SENSOR
OCT.
LBL.
c-2
c-4
273
343
344
346
347
352
354
355
356
370
377
SELF
TEST
429 PARAMETER
GPS SENSOR STATUS
DESTINATION HIL
DESTINATION VIL
ALT WAYPOINT VIL
ALT WAYPOINT HIL
MAINTENANCE DISC 1
MAINTENANCE DISC 2
MAINTENANCE DISC
MAINTENANCE DISC 3
GNSS HEIGHT
EQUIPMENT ID
[c]
[c]
NORM
TEST
RESERVED
RESERVED
TEST
RESERVED
RESERVED
RESERVED
TEST
NORM
NORM
NORM
AIDED
(ALT/CLK
AIDING
NAV MODE
HFOM >16)
NORM
NORM
(ALT/CLK
AIDING
NAV
MODE [a]
HFOM <16
NORM
NORM
NORM
FAIL
NORM
NORM
NORM
FAIL
NCD
NORM
NCD
NORM
NORM
NORM
FAIL
NORM
INITIAL
ACQUISITION
MODE
FAULT
MODE
[a] The GNSSU Navigation Solution is output when the accuracy computation (HFOM) determines the solution should
be within 16 nmi of the actual position (95%).
c-2
[b] In addition to the situation of a normal NCD where there exists an inadequate constellation configuration, the SSM
should be set to NCD when the calculated values exceed their respective maximum range definition.
[c] Since the predictive RAIM ETA and HIL labels contain bits of status information, the SSM is NORM in the
conditions stated above. With the SSMs NORM, the HIL value should be set to full scale when it is unknown.
However, the SSM of the particular HIL sequence may be set NCD during computation of new requests but the
request should be acknowledged with an ETA/HIL with NORM SSMs according to Appendix C.
ARINC CHARACTERISTIC 743A - Page 43
ATTACHMENT 5-1
GPS 2 MCU CONFIGURATION INTERFERENCE LEVEL
c-3
NOTE: This plot reflects interference levels at the antenna port.
*Reproduced from RTCA DO-228
ARINC CHARACTERISTIC 743A - Page 44
ATTACHMENT 5-2
IN-BAND AND NEAR-BAND INTERFERENCE ENVIRONMENTS
c-3
*Reproduced from RTCA DO-229
ARINC CHARACTERISTIC 743A - Page 45
ATTACHMENT 5-3
ANTENNA/PREAMP SIGNAL REJECTION
c-3
*Reproduced from RTCA DO-228
ARINC CHARACTERISTIC 743A - Page 46
ATTACHMENT 5-4
GPS ALTERNATE CONFIGURATION INTERFERENCE LEVEL
c-3
Deleted by Supplement 3
ARINC CHARACTERISTIC 743A - Page 47
ATTACHMENT 5-5
GPS/GLONASS ALTERNATE CONFIGURATION INTERFERENCE LEVEL
c-2
ARINC CHARACTERISTIC 743A - Page 48
ATTACHMENT 6
ENVIRONMENTAL TEST CATEGORIES
c-4
The following RTCA DO-160D categories apply to the environmental specification of the ARINC 743A Global Navigation
Satellite System (GNSS) equipment. This list is purely an example. Manufacturers should refer to the latest versions of DO160, the relevant MOPS and also the OEMs equipment requirements in order to obtain a definitive list of environmental test
requirements.
UNIT LOCATION
DO-160D
Section
Electronics
Rack
Cockpit
External to
Skin of A/C
Internal to
Upper
Fuselage
Temperature & Altitude
4
B1
B1
D2
B1
In-Flight Loss of Cooling
4.5.4
Z
Z
--
Z
Temperature Variation
5
B
B
A
B
Humidity (3)
6
A
A
B
A
Shock
7
A
B
A
A
Vibration (1,2)
8
S or S2
S or S2
S or S2
S or S2
Explosion
9
X
X
X
X
Waterproofness
10
X
X
S
X
Fluids
11
X
X
F(4)
X
Sand & Dust
12
X
X
D
X
Fungus
13
X
X
X
X
Salt Spray
14
X
X
S
X
Magnetic Effect
15
C
Z
A or B
C
Power Input
16
E (AC Pwr)
A (DC Pwr)
E (AC Pwr)
A (DC Pwr)
E (AC Pwr)
A (DC Pwr)
E (AC Pwr)
A (DC Pwr)
Voltage Spike
17
A
A
A
A
Audio Frequency Conducted
Susceptibility
18
E (AC Pwr)
Z (DC Pwr)
E (AC Pwr)
Z (DC Pwr)
E (AC Pwr)
Z (DC Pwr)
E (AC Pwr)
Z (DC Pwr)
Induced Signal Susceptibility
19
Z
Z
Z
Z
Radio Frequency Susceptibility
20
V
V
W
V
c-4
Spurious Radio Frequency
21
L
M
H
L
c-3
Lightning Induced Effects
22
A3E3
A3E3
A3E3
A3E3
Lightning Direct Effects
23
X
X
2A
X
Icing
24
X
X
C(5)
X
ENVIRONMENT (DO-160D)
c-4
c-4
1. The use of alternative categories may be necessary if the installation is to be made in other than turbine-powered fixedwing aircraft. Refer to RTCA DO-160D.
c-4
2. Allows the alternative already provided in RTCA DO-160D (Sinewave or Random).
3. Rack mounted and cockpit mounted units should withstand spillage of liquids (beverages).
4. Fluid susceptibility for solvents, cleaning and de-icing fluids.
5. The antenna should operate with an ice coating of 0.50 inches or less.
ARINC CHARACTERISTIC 743A - Page 49
ATTACHMENT 7-1
GNSS ANTENNA FOOTPRINT
ARINC CHARACTERISTIC 743A - Page 50
ATTACHMENT 7-2
ANTENNA EVALUATION GROUND PLANE
ARINC CHARACTERISTIC 743A - Page 51
ATTACHMENT 8
GNSS TIME MARK
The time mark provides for an ARINC 743A GPS receiver to be synchronized with other aircraft systems. The electrical
characteristics are specified in Figure 8-1. A generator circuit meeting these requirements results in a low impedance (100
ohms or less) balanced voltage source that will produce a differential voltage applied to the interconnecting cable in the
range of 1.4 volts to 6 volts. The signaling senses of the voltages appearing across the interconnection cable are defined as
follows.
a.
The A terminal of the generator should be positive with respect to the B terminal for a logic binary 1.
b.
The A terminal of the generator should be negative with respect to the B terminal for a logic binary 0.
1.1 Vse
0.9 Vse
0.1 Vse
Tb
Tr
Tf
Vss = Difference in steady state voltages
Figure 8-1 Time Mark Generator Output Signal Wave Form
Tb should be 1.0 ms ±.01 ms and should occur once each second with the rising edge (0 to 1 transition) at the EPOCH of the
ARINC 743A user clock output (1 hertz).
During transitions of the generator output between alternating binary states (one-zero-one-zero, etc.) the differential voltage
measured across a 100 ohm +10% test load connected between the generator output terminals should be such that the voltage
monotonically changes between 0.1 and 0.9 of Vss within 200 ns (Tr and Tf). Thereafter, the signal voltage should not vary
more than 10% of Vss from the steady state value, until the next binary transition occurs, and at no time should the
instantaneous voltage Vss exceed 6.0 volts, nor be less than 1.4 volts. Vss is defined as the voltage difference between the
two steady state values of the generator output.
ARINC CHARACTERISTIC 743A - Page 52
ATTACHMENT 8
GNSS TIME MARK
The balanced voltage digital interface circuit is shown in Figure 8-2. The circuit consists of three parts: the generator (G),
the balanced interconnecting cable, and the load. The load is comprised of one or more receivers (R) and an optional cable
termination resistance (Rt). The electrical characteristics of the generator and receiver are specified in terms of direct
electrical measurements while the interconnecting cable is described in terms of its electrical and physical characteristics.
B a la n c e d
I n t e r c o n n e c ti n g
C a b le
G e n e r a to r
L oad
R e c e iv e r
C a b le
T e r m i n a ti o n
A
A'
G
Rt
B
R
B'
T o a d d it io n a l
r e c e iv e r s i f a n y
Vg
C
C'
Rt
Vg
A, B
A',B'
C
C'
=
=
=
=
=
=
Optional Cable Termination Resistance
Ground Potential Difference
Generator Interface Points
Load Interface Points
Generator Circuit Ground
Load Circuit Ground
Figure 8-2 Time Mark Interface Circuit
The timing relationship for the GPS Time Mark output from the ARINC 743 GPSSU is defined in Figure 8-3. The ARINC
429 outputs labels 150, 140 and 141 to define the UTC time of the GPSSU Epoch.
ARINC CHARACTERISTIC 743A - Page 53
ATTACHMENT 8
GNSS TIME MARK
Time Mark
(USER)
LAT/LON ALT
TK/GS
NS-EW VEL
VERT SPEED
UTC
Valid
Output
SV SOLUTION
Computation Time
Max Time = 200 msec
Hardware Satellite
Measurement Time
SV POS
PR PRR
UTC MEAS TIME
Output
Computation Time
SV DATA
USER TIME
EPOCH
(SV Solution Valid)
UTC EPOCH
Satellite
Measurement
Valid
125 - UTC of Time Mark - BCD
140 - UTC of Time Mark - BNR (fractions to 1 µsec)
141 - UTC of Time Mark - BNR (fractions to 1 nsec)
150 - UTC of Time Mark - BNR (to 1 sec)
074 - UTC MEASUREMENT TIME - BNR (fractions to 10 µsec)
The “Time Mark” is used by other systems as an accurate reference to UTC.
Satellite measurements must be made in USER Time with the USER clock errors. The time of measurement output
should be converted to UTC.
LAT/LON
ALT
TK/GS
NS-EW VEL
VERT SPD
Based on the computations for the User Solution at the User Time.
One second EPOCH
UTC
UTC at the USER one second EPOCH (Time Mark). The resolution should be one nanosecond.
NOTE: The navigation and satellite data blocks should start with status and end with UTC time.
Figure 8-3 Timing Relationships
Tsky = 100oK
C = -130 dBm
Configuration 1
Configuration 2
Industry Supported
Installations
2 MCU
GNSS SU
29.5 dB ± 3 dB
33.0 dB ± 3 dB
Amplifier
Gain
3 dB to 12 dB
6 dB to 15 dB
Acceptable Cable
Loss
C/NO = 36 dBHz @ 20 MHz BW
C = -134.5 dBm
Gcable = -1.5 dB
Tcable = 120oK
ALTERNATE CONFIGURATION
T = 100oK + 120oK = 220oK
C/N0 = 40.7 dBHz
Acquisition
C = -136dBm
C/N0 = 37.7 dBHz
Tracking
C = -139 dBm
ALTERNATE CONFIGURATION
GNSS SU
1 dB
1dB
VSWR and
Parasitic Losses
C =-134.5 + GLNA + Gcable dBm + GVSWR dBm
-121 dBm < C < -104.5 dBm
13.5 dB < GLNA + Gcable +GVSWR< 30 dB
The C/N0 shown here represents the signal to noise ratio presented to the input of
the equipment and does not account for the RF front-end/stage of the equipment
(i.e., does not account for the receiver’s gain and noise figure), or necessarily reflect
the C/N0 contained in label 060.
Cable Gain = Gcable
Tcable = 300oK
VSWR and Parasitic
Losses = GVSWR dBm
Gantenna = -4.5 dB
Preamp Gain = GLNA
Noise Figure = 4 dB
TLNA/Filter = 438oK
C = -134.5 + GLNA dBm
LNA
Gantenna = -4.5 dB
C = -134.5 dBm
2 MCU CONFIGURATION GNSS SU
c-4
Tsky = 100oK
C = -130 dBm
ARINC CHARACTERISTIC 743A - Page 54
ATTACHMENT 9
GNSS SIGNAL LOSSES
*The analysis does not include the noise generated by the devices within the dashed lines.
ARINC CHARACTERISTIC 743A - Page 55
ATTACHMENT 10
MODE TRANSITION TABLE
Self Test
A
Initialization
Fault
Aided
Alt/Clk Aiding
GBAS Nav
SBAS Nav
Navigation
Acquisition
Initialization
Mode
Transitioning
From:
Self Test
Mode
Transitioning
To:
B
C
Acquisition
B
E
F
G
F
G
B
Navigation
H
SBAS Nav
H
E
GBAS Nav
H
E
Alt/Clk Aiding
H
E
B
Aided
H
E
B
Fault
J
L
G
F
D
Indicates an Illegal Transition
B
B
B
c-4
ARINC CHARACTERISTIC 743A - Page 56
ATTACHMENT 10
MODE TRANSITION TABLE
Conditions:
c-4
A
-
Unit Successfully completes self test and no critical faults are found.
B
-
Built In Test (BIT) equipment detects a critical sensor hardware fault which adversely affects the navigation
and time outputs.
C
-
GNSS function successfully completes initialization and no fault conditions occur.
D
-
Built In Test (BIT) equipment determines the critical sensor hardware fault which resulted in transition to the
fault mode is no longer present.
E
-
X + !Y + !Z
F
-
X + Y + !Z
G
-
X + (Y or !Y) + Z + = X + Z
H
-
!X (unless optional alt/clock aiding mode or aided mode are implemented)
J
-
!X for less than allowable clock coasting interval
L
-
!X (if implemented) + aiding data available
S
-
Final Approach Segment (FAS) data is available and validated by CRC.
X
-
Sufficient pseudorange measurements are available to compute a position solution
Y
-
SBAS augmentation data has been decoded and validated by CRC
Z
-
GBAS augmentation data has been decoded and validated by CRC
!
-
The exclamation mark preceding the letter of the condition means the opposite condition.
ARINC CHARACTERISTIC 743A - Page 57
APPENDIX A
DIFFERENTIAL CORRECTIONS
REFER TO APPENDIX A OF ARINC CHARACTERISTIC 755, MULTI-MODE RECEIVER (MMR) - DIGITAL
ARINC CHARACTERISTIC 743A - Page 58
APPENDIX B
SATELLITE BASED AUGMENTATION SYSTEM PROVISIONS
1.0 Overview
The Satellite Based Augmentation System (SBAS) is an augmentation to the ICAO Global Navigation Satellite
System (GNSS) that calculates integrity and correction data on the ground, and uses geostationary satellites to
broadcast that data and provide an additional ranging signal to GNSS/ SBAS users.
COMMENTARY
This appendix describes the amendments to ARINC Characteristic 743A to provide general and specific
design guidance for SBAS classes Beta-1 and Beta-2 sensors, supporting en route, terminal, or/and nonprecision approach phases of flight. These amendments are to be consistent with the requirements specified
by RTCA DO-229, “Minimum Operational Performance Standards for Global Positioning System/Wide
Area Augmentation System Airborne Equipment.”
2.0 Signal Processing Characteristics
Refer to the Sensor Performance Characteristics for the 2 MCU and Alternate Configuration provided in Sections 4.5
and 4.6.
3.0 Integrity Monitoring
ARINC 429 Label 130 Autonomous Horizontal Integrity Limit should contain the SBAS horizontal protection limit
(HPLSBAS) when the GNSS Sensor Operational Mode parameter, contained in output Label 273, is set to SBAS=
01101Bin.
<RTCA DO-229 Paragraph 2.1.2.2.2>
c-4
Label 130 Autonomous Horizontal Integrity Limit should contain the horizontal protection limit computed by the
autonomous fault detection algorithm (HPLFD) whenever HPLSBAS cannot be computed, but sufficient observables
exist to compute HPLFD (i.e., five or more satellites, or four or more satellites and altitude).
<RTCA DO-229 Paragraph 2.1.2.2.2>
COMMENTARY
HPLSBAS and HPLFD are functionally equivalent forms of integrity in that both are specified to have a
missed detection probability of 10-5 HPLSBAS is provided when the sensor can supply SBAS integrity and
HPLFD when the sensor must use autonomous fault detection.
The value of HIL should be set to the maximum, representable value when the value of HPLFD is greater than what
can be physically represented by label 130.
<Derived>
Label 130 should be set NCD when there is an insufficient number of satellites or data to compute HPLSBAS or
HPLFD.
<RTCA DO-229 Paragraph 2.1.1.13.1>
4.0 SBAS Interface Requirements
4.1 Inputs
No new input requirements have been specified by RTCA D)-229 for en route, terminal, or non –precision approach
operations.
4.2 Outputs
ARINC CHARACTERISTIC 743A - Page 59
APPENDIX B
SATELLITE BASED AUGMENTATION SYSTEM PROVISIONS
4.2.1 Exclusion
Bit 23 of Label 060 - ARINC 429 Measurement Status should be set to Invalid/Isolated = 0 for any satellite whose
measurements has been excluded from the navigation solution. At a minimum, satellites should be excluded for the
following conditions:
a. Exclusion by the Step Detector.
b. The satellite is declared SBAS UNHEALTHY internal to the sensor and the sensor is operating in a
SBAS mode.
c. The satellite is declared GPS UNHEALTHY internal to the sensor.
d. The satellite has been excluded by the fault detection and exclusion (FDE) algorithm.
Otherwise, if the measurement is incorporated into the navigation solution, the bit should be set Valid = 1.
<RTCA DO-229 Paragraphs 2.1.1.5.1, 2.1.1.5.2, 2.1.1.5.5, 2.1.1.6>
4.2.2 Satellite Position
The satellite positions, as provided by labels 065, 066, 070, 071, 072, and 073 should be based upon ephemeris data
that has been verified to be valid by successfully collecting valid ephemeris data twice.
<RTCA DO-229 Paragraph 2.1.1.2>
4.2.3 Failure Warning Enunciation
COMMENTARY
The absence of ARINC 429 labels on the GNSS output buses, should indicate loss of power to the sensor
and constitute a navigation alert.
<RTCA DO-229 Paragraph 2.1.1.13.2a>
In the event the sensor has detected a fatal malfunction or failure, the GNSS sensor should set Bit 25, 26, and 27 as
appropriate in Label 355 - GNSS Fault Summary Label to Failed = 1, set the SSM of all labels as indicated by
Attachment 4-4, and set the GPS Sensor Operational Mode parameter, contained in output Label 273, to
Fault=11111.
<RTCA DO-229 Paragraph 2.1.1.13.2b>
When there is an inadequate number of observables to compute a position solution for five or more seconds, the
GNSS sensor should set the SSM’s of all labels as indicated by Attachment 4-4.
<RTCA DO-229 Paragraph 2.1.1.13.2c>
When FDE has detected a fault and the fault has not been excluded, bit 11 of label 130 - Autonomous Horizontal
Integrity Limit, should be set = 1, otherwise = 0. The time to alert is 8 seconds for beta sensors.
<RTCA DO-229 Paragraph 2.1.1.13.2d>
<RTCA DO-229 Paragraphs 2.1.2.2.2.2.1>
When FDE has detected a fault and the fault has not been excluded, it is recommended that the Horizontal
uncertainty limit (HUL) be broadcast in the label 130 - Autonomous Horizontal Integrity Limit, and bit 11 set = 1,
otherwise = 0. The time to alert is 8 seconds for beta sensors.
COMMENTARY
HUL provides a real-time estimate of the error bound of the PVT solution block.
<RTCA DO-229 Paragraph 2.1.1.13.2d>
<RTCA DO-229 Paragraphs 2.1.2.2.2.2.1>
<Derived>
If the failed satellite(s) is (are) isolated and excluded, associated Label 060 should be updated per Appendix B.4.2.1
and, provided no additional failures are detected and FD is still available, bit 11 of label 130 - Autonomous
Horizontal Integrity Limit, should be set = 0.
<RTCA DO-229 Paragraph 2.1.1.13.2d>
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ARINC CHARACTERISTIC 743A - Page 60
APPENDIX B
SATELLITE BASED AUGMENTATION SYSTEM PROVISIONS
4.2.4 Satellite Measurement Block
COMMENTARY
Currently, Label 060 can only accommodate 63 unique SVIDs. Tying this parameter to the actual PRN
number associated with the GPS, GLONASS, or SBAS satellite is not possible and not necessary (GPS has
reserved 1-37, SBAS is assigned 120-138, and GLONASS is probably similar to GPS). The only reason for
this parameter is to mark unique measurement blocks. The actual PRN or SVID identifiers are only useful
for purposes of debugging or testing the unit. The SV positions and associated UTC times will uniquely,
albeit indirectly, identify each unique satellite.
While the sensor is operating in a SBAS mode, the satellite pseudorange and deltarange measurements should reflect
those measurements used to compute the PVT solution block and HPLSBAS or HPLFD.
<Derived>
If the GNSS Sensor Operational Mode in Label 273 - Sensor Status indicates Navigation, the satellite measurement
block should be corrected for satellite clock, ionospheric, and tropospheric errors.
<ARINC 743A-4>
<Derived>
c-4
If the GNSS Sensor Operational Mode in Label 273 - Sensor Status indicates SBAS and the sensor computes
HPLSBAS using the SBAS Fast, Long-term, and Ionospheric corrections, the satellite measurement block should be
corrected for tropospheric errors and the SBAS Fast, Long-term, and Ionospheric corrections. All other
measurements not corrected in this manner should have bit 23-SVID Status/Isolation set to Invalid/Isolated = 0 and
Bit 22-Range Rate or Delta Range Status set to Invalid = 0 in their associated Label 060-ARINC 429 Measurement
Status.
<RTCA DO-229 Appendix J>
<Derived>
If the GNSS Sensor Operational Mode in Label 273 - Sensor Status indicates SBAS and the sensor computes
HPLSBAS using the SBAS Fast and Long-term corrections, the satellite measurement block should be corrected for
tropospheric errors, ionospheric errors (using the single frequency Kolbuchar model) and the SBAS Fast and Longterm corrections. All other measurements not corrected in this manner should have bit 23-SVID Status/Isolation set
to Invalid/Isolated = 0 and Bit 22-Range Rate or Delta Range Status set to Invalid = 0 in their associated Label 60ARINC 429 Measurement Status.
<RTCA DO-229 Appendix J>
<Derived>
If the GNSS Sensor Operational Mode in Label 273 - Sensor Status indicates SBAS and the sensor computes
HPLSBAS using only the SBAS Fast corrections, the satellite measurement block should be corrected for
tropospheric errors, ionospheric errors (using the single frequency Kolbuchar model) and the SBAS Fast corrections.
All other measurements not corrected in this manner should have bit 23-SVID Status/Isolation set to Invalid/Isolated
= 0 and Bit 22-Range Rate or Delta Range Status set to Invalid = 0 in their associated Label 60-ARINC 429
Measurement Status.
COMMENTARY
An issue to be resolved with RTCA SC-159 WG-2 is whether the clock corrections provided in the satellite
50 Hz downlink can be applied to this case and the next case.
<RTCA DO-229 Appendix J.3>
<Derived>
If the GNSS Sensor Operational Mode in Label 273 - Sensor Status indicates SBAS and the sensor computes
HPLSBAS applying no SBAS corrections, the satellite measurement block should be corrected for tropospheric
errors and ionospheric errors (using the single frequency Kolbuchar model). All other measurements not corrected in
this manner should have bit 23-SVID Status/Isolation set to Invalid/Isolated = 0 and Bit 22-Range Rate or Delta
Range Status set to Invalid = 0 in their associated Label 60-ARINC 429 Measurement Status.
<RTCA DO-229 Appendix J.4>
<Derived>
ARINC CHARACTERISTIC 743A - Page 61
APPENDIX B
SATELLITE BASED AUGMENTATION SYSTEM PROVISIONS
4.2.5 Navigation Block
The GNSS function should compute an estimate of position, time, and velocity that is coincident, in time. The
navigation block should be completely transmitted within 200 milliseconds of the applicable time mark event (i.e.,
the leading edge of the time mark discrete). Refer to Figure B-1.
<RTCA DO-229 Paragraph 2.1.2.6.2>
COMMENTARY
The Timing diagram does not fully constrain when the measurement integration endpoint could occur.
<Derived>
SV Measurement
Integration Endpoint
c-3
PVT Valid
Time Mark Pulse
Max Meas. Latency As
Applied to PVT Data
Max PVT Dispatch Latency
Meas. Update Interval
Figure B-1
Minimum Timing Requirements
500 ms
200 ms
1 second
ARINC CHARACTERISTIC 743A - Page 62
APPENDIX C
PREDICTIVE RAIM CAPABILITY
1.0
Predictive RAIM
Predictive Receiver Autonomous Integrity Monitor (PRAIM) is the estimated values of the Horizontal Integrity Limit (HIL)
at some future place and time. Predictive RAIM is a capability that is necessary for receivers that desire compliance with
TSO-C129 Classes B1 and C1 requirements. The characteristics described in this appendix are only applicable for receivers
designed to be certified to those requirements. Therefore the label definitions are optional for receivers not intending to
comply with TSO-C129 B1 and C1. This capability is defined to be compliant with the following TSO-C129 paragraphs:
(a)(3)(xv)1-3c, (a)(3)(xxi)1-2, and (a)(5)(vii)4a-4d.
Providing certain Predictive RAIM capabilities will require detailed communication protocol between the GNSSU and the
FMS. As the characteristics herein apply only to the GNSSU, commentary is provided to describe the expected capabilities
to be provided by the FMS.
The Predictive RAIM definition includes the following types of RAIM predictions: Destination, Alternate Waypoint. Also
the capability to de-select or enable satellites is defined. The Destination and Alternate Waypoint predictions are requested
predictions at a specific location and estimated time of arrival (ETA). RAIM predictions are generated at the request of the
FMS for flight planning purposes. Satellite de-selection provides the capability to manually de-select or enable satellites for
use in RAIM predictions. Such information for de-selecting satellites may be retrieved from the NOTAM system.
1.1
Destination and Alternate Waypoint Predictive RAIM
The Destination/Alternate Waypoint RAIM predictions provide the RAIM values at a specified latitude and longitude
location and time (ETA). Both of these prediction types are described together in this paragraph since they operate in the
same manner. Separate label sets are defined on the inputs and outputs so the FMS can request and receive distinct
predictions for the Destination and/or an Alternate Waypoint. An FMS can independently request predictions for a
continuously updated destination (automatic) and an on-demand (pilot initiated) entry using the two request types.
c-2
The GNSSU echoes the ETA input label onto the output bus and updates the output values for the Horizontal Integrity Limit
(HIL) predictions that are associated with the ETA requests made from the FMS.
These outputs are transmitted at a 1 hertz rate. The RAIM predictions at the specified location in the request should be
provided over a time span of + 15 minutes about the requested ETA in 5 minute intervals. Therefore, it takes a set of seven
ETA, HIL label output responses from the GNSSU to complete a prediction for one ETA/location request (Reference
Section 1.1.3).
Since the requests can be received from two independent FMS bus inputs, the GNSSU should provide responses for each
FMS input bus, identifying the requester in the response. Predictive RAIM request inputs will be received on either
FMS/IRS buses (#1 and #2) or DADC/FMS buses (#1 and #2). However, the GNSSU is not expected to receive inputs
simultaneously on both FMS/IRS and DADC/FMS buses. Only one set of two FMS input buses are expected to be used in
any given installation.
COMMENTARY
It is anticipated that GNSSU installations will require inputs from both the FMS and the IRS. A GNSSU with
predictive RAIM capability will especially require a direct FMS input. Previous definitions allowed for input bus
connections to a DADC and FMS or IRS. To allow for maximum flexibility and maintain compatibility to previous
configurations, it recommended that the input buses be dual purpose and recognize a combination of labels to provide
DADC/FMS and IRS/FMS source inputs. The FMS will be wired to either the FMS/IRS input ports or the
DADC/FMS ports. It will not be acceptable for installers to wire up the FMS to all four ports at one time, nor will it
be acceptable for installers to wire FMS 1 to a IRS/FMS port and FMS 2 to a DADC/FMS port.
1.1.1 Destination and Alternate Waypoint Request Protocol
Both the Destination and Alternate Waypoint RAIM requests will be received as a set of five labels that are burst from the
requesting device when a prediction is desired. The GNSSU should recognize a request for a RAIM prediction when it
receives a set of five valid Destination RAIM input labels 152, 144, 143, 146 and 170 labels (Destination ETA, Latitude,
Longitude and Satellite De-selection labels) or a set of five valid Alternate Waypoint RAIM input labels 167, 214, 216, 146,
and 170 words (Alternate Waypoint ETA, Latitude, Longitude and Satellite De-selection labels). A valid reception consists
of a complete set of these input labels. The set of two Satellite De-selection words (labels 146 and 170) is required to cover
GPS satellites 1 through 32. Bit 11 of ARINC labels 146 and 147 will indicate the de-selection type, reference Figure 1.2A.
The SDI bits of the input labels should match the SDI setting of the GNSSU receiver or be set to “all call (00)” to be
recognized as a valid request. When SDI of the input label set are “all call” the GNSSU is to respond regardless of its SDI
discrete strapping.
ARINC CHARACTERISTIC 743A - Page 63
Destination Predictive
RAIM Request
Sat De-sel (170, 0)
Sat De-sel (146, 0)
Longitude (216)
Latitude (214)
ETA (167)
Sat De-sel (170, 0)
Sat De-sel (146, 0)
Longitude (143)
Latitude (144)
ETA (152)
APPENDIX C
PREDICTIVE RAIM CAPABILITY
Alternate Waypoint Predictive
RAIM Request
Figure 1 Alternate Waypoint and Destination Predictive RAIM Request Input Label Sets
Upon receiving the request, the GNSSU should acknowledge the predictive RAIM request by updating the appropriate ETA
Response and Predictive RAIM HIL output labels for the request type and input bus being acknowledged. This
acknowledgement includes setting the HIL Integrity Sequence Counter to a “000” state, echoing the same time value as in
the ETA request, echoing the SDI of the requesting FMS SDI in the “FMS Request Designator” bits, and echoing the
Sequence Bit from the ETA label input (see Figures 3A and 3B).
The GNSSU should acknowledge receipt of the request within 2 seconds of receiving the request. The acknowledgment
should not wait for completion of any space-time point computations.
After the acknowledgment of the predictive RAIM request, the GNSSU should then proceed to compute and output the ETA
and Predictive RAIM HIL label sets for each space-time point. See Section 1.1.3 for a description of the output sequence.
COMMENTARY
Both the ETA Response and Predictive RAIM HIL labels provide a sequence bit which is an echo of the sequence bit
in the ETA Input request label. It is expected that the FMS will toggle the sequence bit of subsequent requests such
that the output responses can be distinguished from one another.
ARINC BIT
BIT 32
BIT 31-30
Description
Parity (Odd)
Sign Status Matrix (SSM)
BIT 29
BIT 28-24
BIT 23-18
BIT 17
BIT 16
Reserved
Hours
Minutes
Spare
ETA Request Sequence BIT
BIT 15-14
Requesting FMS SDI
BIT 13-12
BIT 11
Spare
Reserved for
Baro-Corrected Alt. to be Applied
BIT 10-9
Source/Destination Identifier
BIT 8-1
Octal Label (167 or 152)
c-2
Setting
Fail Warning
No Computed Data
Functional Test
Normal Operation
Always = 0
0-23 hours
0-59 minutes
= 00
= 01
= 10
= 11
Sequence bit used to distinguish
consecutive requests with same ETA.
00 = Not Defined
01 = FMS 1
10 = FMS 2
11 = FMS 3
0 = Baro-Correction not applied
1 = Baro-Correction applied
All Call
= 00
GNSSU 1
= 01
GNSSU 2
= 10
GNSSU 3
= 11
Figure 2 - Destination and Alternate Waypoint ETA Input Label Format
ARINC CHARACTERISTIC 743A - Page 64
APPENDIX C
PREDICTIVE RAIM CAPABILITY
1.1.2 Multiple Predictive RAIM Request Processing
Since the GNSSU is capable of receiving multiple types of requests (Destination and Alternate Waypoint) independently
from one of two input buses, a priority based request handling method is needed. The GNSSU should recognize the
following four inputs as independent requests.
1.
2.
3.
4.
Input bus #1 Alternate Waypoint Request
Input bus #2 Alternate Waypoint Request
Input bus #1 Destination Waypoint Request
Input bus #2 Destination Waypoint Request
The GNSSU should handle all four RAIM prediction requests, whether processed sequentially or in parallel or whether the
request are received at the same time or not. If the GNSSU receives a second valid request matching the current request
being processed, the previous request will be terminated.
COMMENTARY
The GNSSU outputs 2 sets of predictive RAIM labels, one for inputs received on bus #1 and another for inputs
received on bus #2. This will allow the GNSSU to acknowledge either request as soon as the request is received from
the FMS. It will also enable the FMS connected to port 1 and the FMS connected to port 2 to operate independently
and in the event that both FMS devices are making a request at the same time, the acknowledgment and predictive
RAIM values will not be lost. This will also allow the FMS to manage predictive RAIM requests independently
without requiring the GNSSU to hold data valid for two or three seconds. The GNSSU will react the same to either
FMS request without the complication of special cases in the GNSSU to hold data valid and delay acknowledgments.
If either FMS is making a request at the same time, the predictive RAIM values will be delayed for the last request
but the acknowledgment will not.
c-2
Typically, the time between requests will be minutes. However, since the FMS is responding to pilot inputs and when
the pilot is constructing a flight plan, the request may be as quick as a pilot may be able to add a way point (on the
order of seconds). The predictions themselves may be on the order of 1-10 seconds.
1.1.3 Destination and Alternate Waypoint Output Labels and Output Timing
For both the Destination and Alternate Waypoint RAIM predictions, the GNSSU will output two sets of two response labels
comprised of ETA, HIL each second, one corresponding to the request from FMS bus #1 inputs and the other to FMS bus #2
inputs. Each FMS label set is to be transmitted once per second with the alternate FMS bus label sets separated by 0.5
seconds ± 200 ms. The maximum spacing between labels within a set is to be less than or equal to 5 ms.
For each predictive RAIM type and bus, one HIL value is output each second. A complete RAIM prediction output for a
single request consists of a total of seven space-time point HIL values as shown below. When the complete sets of HIL
values are available, the GNSSU will sequence through all seven space-time points every 7 seconds with the space time point
indicated in the Integrity Sequence Counter. The sequence order is not critical but all seven values must be output in a
rotating sequence with the Integrity Counter set 001 through 111. Prior to all seven space-time points being available, the
GNSSU may output each new value as it becomes available to avoid output delays. Space-time point HIL values for a new
request may be set to NCD or not output until they become available. It is permissible to repeat space-time points until the
next set becomes available.
Space-Time Point
Time
1
2
3
4
5
6
7
ETA +0
ETA - 5 min
ETA + 5 min
ETA - 10 min
ETA + 10 min
ETA - 15 min
ETA + 15 min
Integrity Sequence Counter
001
010
011
100
101
110
111
For Destination predictive RAIM the label set and output order should be 162 and 343. For Alternate Waypoint predictive
RAIM the label set and output order should be 163 and 347. The format for these labels is provided in Figures 3A and 3B.
The SDI of the requesting FMS (received from the ETA input) is provided in bits 15-14 of the ETA Response and Predictive
RAIM HIL output labels. A sequence bit is provided in bits 16 of the ETA Response and HIL outputs labels which is an
echo of the sequence bit received in the ETA input request label.
ARINC CHARACTERISTIC 743A - Page 65
APPENDIX C
PREDICTIVE RAIM CAPABILITY
ARINC BIT
Description
BIT 32
Parity (Odd)
BIT 31-30
Sign Status Matrix (SSM)
Fail Warning
No Computed Data
Functional Test
Normal Operation
BIT 29
Reserved
Always = 0
BIT 28-24
Hours (Note 1)
Echoed from request
BIT 23-18
Minutes (Note 1)
Echoed from request
BIT 17
Date/Time (Note 2)
GNSSU has determined times
GNSSU has not determined times
BIT 16
ETA Request Sequence BIT (Note 3)
Echoes Sequence Bit Received from FMS
BIT 15-14
FMS Request Designator (Note 4)
00 = Powerup State
01 = FMS 1
10 = FMS 2
11 = FMS 3
BIT 13
Request Bus Designator
Response to Port 1 bus
Response to Port 2 bus
=0
=1
BIT 12
Invalid Almanac (Note 2)
Almanac Valid
Almanac Invalid
=0
=1
BIT 11
Reserved for
Baro-Corrected was Applied
BIT 10-9
Source/Destination Identifier
BIT 8-1
Octal Label (162 or 163)
Setting
= 00
= 01
= 10
= 11
=0
=1
0 = Baro-Correction not applied
1 = Baro-Correction applied
Not Used
GNSSU 1
GNSSU 2
GNSSU 3
= 00
= 01
= 10
= 11
Figure 3A Destination and Alternate Waypoint ETA Response Output Label Format
Note 1: The Hours and Minutes values are to be set to zero at powerup prior to the first request.
Note 2: The Date/Time and Invalid Almanac bits are set autonomously by the GNSSU such that no request is required to
update this information. The PRAIM Unavailable (bit 17) of the PRAIM HIL output label is the logical “or” of bits
12 and 17 from this label.
The almanac should be considered invalid (bit 12=1) when the almanac age (TOA) is greater than 3.5 days old.
Since ETA and almanac validity are relative to current date and time, the GNSSU needs to know the Time/Date for
Predictive RAIM. The GNSSU may determine current date and time (bit 17=0) from tracked satellites or from
initialization inputs. Note that when using initialization data, the GNSSU will assume it is to be valid for use.
Note 3: The Sequence Bit is set to 0 after powerup and prior to receiving the first request. Subsequently the bit echoes the
state of the FMS ETA Input label Sequence Bit (Bit 16) for which this output is providing a response. This bit is
logically the same as the Sequence Bit (Bit 16) in the PRAIM HIL Output Label. The sequence bit is used to
distinguish consecutive requests with the same ETA.
Note 4: The FMS Request Designator is set to 00 after powerup and prior to receiving the first request. Subsequently the
bit echoes the state of the FMS ETA Input label Requesting FMS SDI bits (Bit 15-14) for which this output is
providing a response.
c-2
ARINC CHARACTERISTIC 743A - Page 66
APPENDIX C
PREDICTIVE RAIM CAPABILITY
ARINC BIT
Description
BIT 32
Parity (Odd)
BIT 31-30
Sign Status Matrix (SSM)
Fail Warning
No Computed Data
Functional Test
Normal Operation
BIT 29
Reserved
Always = 0
BIT 28-18
Integrity Limit (Note 1)
BIT 17
PRAIM Unavailable (Note 2)
Available = 0
Unavailable = 1
BIT 16
Sequence Bit (Note 3)
Echoes Sequence Bit Received from FMS
BIT 15-14
FMS Request Designator
Powerup (Note 4)
FMS 1
FMS 2
FMS 3
= 00
= 01
= 10
= 11
BIT 13-11
Integrity Seq Counter
Acknowledge(Note 5)
HIL at ETA
HIL at ETA-5 minutes
HIL at ETA+5 minutes
HIL at ETA-10 minutes
HIL at ETA+10 minutes
HIL at ETA-15 minutes
HIL at ETA+15 minutes
= 000
= 001
= 010
= 011
= 100
= 101
= 110
= 111
BIT 10-9
Source/Destination Identifier
Not Used
GNSSU 1
GNSSU 2
GNSSU 3
= 00
= 01
= 10
= 11
BIT 8-1
Octal Label (347 or 343)
c-2
Setting
= 00
= 01
= 10
= 11
Figure 3B Destination and Alternate Waypoint Predictive RAIM HIL Output Label Format
Note 1: The Integrity Limit value is set full scale at powerup prior to the first request and when the value is greater than 16
nmi or cannot be computed. This field is undefined when the Integrity Sequence Counter is “000.”
Note 2: The PRAIM Unavailable bit is set autonomously by the GNSSU such that no request is required for updating this
information. This bit is the logical “or” of bits 12 and 17 of the ETA Response Output Label.
Note 3: The Sequence Bit is set to 0 after powerup and prior to receiving the first request. Subsequently the bit echoes the
state of the FMS ETA Input label Sequence Bit (Bit 16) for which this output is providing a response. This bit is
logically the same as the Sequence Bit (Bit 16) in the ETA Response Output Label.
Note 4: The FMS Request Designator is set to 00 after powerup and prior to receiving the first request. Subsequently the
bit echoes the state of the FMS ETA Input label Requesting FMS SDI bits (Bit 15-14) for which this output is
providing a response.
Note 5: The Sequence Counter is to be set to the 000 state at powerup and prior to receiving the first request. Subsequently
this state is used to acknowledge a PRAIM request. The Integrity Limit value is not to be interpreted as valid when
the Integrity Sequence Counter is 000.
ARINC CHARACTERISTIC 743A - Page 67
APPENDIX C
PREDICTIVE RAIM CAPABILITY
HIL (port 2) (343)
ETA (port 2) (162)
Dest. response
for port 2
HIL (port 1) (343)
ETA (port 1) (162)
Dest. response
for port 1
HIL (port 2) (343)
ETA (port 2) (162)
Dest. response
for port 2
HIL (port 1) (343)
ETA (port 1) (162)
Dest. response
for port 1
1.0 sec. nominal
0.5 sec. nominal
1.0 sec. nominal
Figure 3C Destination Predictive RAIM Output Timing
Alternate Waypoint
response for port 1
Alternate Waypoint
response for port 2
Alternate Waypoint
response for port 1
Alternate Waypoint
response for port 2
HIL (port 2) (347)
ETA (port 2) (163)
HIL (port 1) (347)
ETA (port 1) (163)
HIL (port 2) (347)
ETA (port 2) (163)
HIL (port 1) (347)
ETA (port 1) (163)
c-2
1.0 sec. nominal
0.5 sec. nominal
1.0 sec. nominal
Figure 3D Alternate Waypoint Predictive RAIM Output Timing
1.2 Satellite De-selection
Satellite de-selection is a capability which allows manual selection of satellites used for predictive RAIM. The capability has
been separated into satellite de-selection which is associated with Destination and Alternate Waypoint predictive RAIM
requests. The de-selection type will be indicated in bit 11 (see Figure 1.2A).
1.2.1 Satellite De-selection Inputs for Predictive RAIM
For Destination and Alternate Waypoint predictive RAIM, the request data set for de-selecting or enabling satellites is
defined in a ARINC 429 input labels 146 and 170 (see Figure 1.2A). These input labels should be received as part of the
predictive request as a burst input (see Section 1.1.1).
COMMENTARY
When the pilot is constructing a flight plan and is expected to determine the RAIM availability for his destination, he
may choose to remove a satellite known to be in error based on information received in a NOTAM. The FMS should
send the satellite de-selection along with the prediction request.
ARINC CHARACTERISTIC 743A - Page 68
APPENDIX C
PREDICTIVE RAIM CAPABILITY
Label 146:
c-2
Bit 32
Bit 31-30
Parity (odd)
Sign Status Matrix
Bit 29
SVID 1
Bit 28
SVID 2
Bit 27
SVID 3
Bit 26
SVID 4
Bit 25
SVID 5
Bit 24
SVID 6
Bit 23
SVID 7
Bit 22
SVID 8
Bit 21
SVID 9
Bit 20
SVID 10
Bit 19
SVID 11
Bit 18
SVID 12
Bit 17
SVID 13
Bit 16
SVID 14
Bit 15
SVID 15
Bit 14
SVID 16
Bit-13,12
Bit-11
Reserved
De-selection type
Bit 10-9
SDI:
Bit 8-1
Octal Label (146)
Normal Operation
No Computed Data
Functional Test
Not Used
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
=00
=01
=10
=11
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
Destination Predictive RAIM
Alternate Predictive RAIM
00 = All Call
01 = GNSSU 1
10 = GNSSU 2
11 = GNSSU 3
=0
=1
Figure 1.2A Satellite De-selection Labels 146, 170
ARINC CHARACTERISTIC 743A - Page 69
APPENDIX C
PREDICTIVE RAIM CAPABILITY
Label 170:
Bit 32
Bit 31-30
Parity (odd)
Sign Status Matrix
Bit 29
SVID 17
Bit 28
SVID 18
Bit 27
SVID 19
Bit 26
SVID 20
Bit 25
SVID 21
Bit 24
SVID 22
Bit 23
SVID 23
Bit 22
SVID 24
Bit 21
SVID 25
Bit 20
SVID 26
Bit 19
SVID 27
Bit 18
SVID 28
Bit 17
SVID 29
Bit 16
SVID 30
Bit 15
SVID 31
Bit 14
SVID 32
Bit-13,12
Bit-11
Reserved
De-selection type
Bit 10-9
SDI:
Bit 8-1
Octal Label (170)
Normal Operation
No Computed Data
Functional Test
Not Used
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
De-select
Enable
=00
=01
=10
=11
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
=1
=0
Destination Predictive RAIM
Alternate Predictive RAIM
00 = All Call
01 = GNSSU 1
10 = GNSSU 2
11 = GNSSU 3
=0
=1
Figure 1.2A Satellite De-selection Labels 146, 170
c-2
ARINC CHARACTERISTIC 743A - Page 70
APPENDIX D
AIRPLANE PERSONALITY DATA MESSAGE (APDM)
DELETED BY SUPPLEMENT 4
ARINC CHARACTERISTIC 743A - Page 71
APPENDIX E
FINAL APPROACH SEGMENT (FAS) DATA MESSAGE (FASDM)
DELETED BY SUPPLEMENT 4
ARINC CHARACTERISTIC 743A - Page 72
APPENDIX F
GLOSSARY OF ABBREVIATIONS AND ACRONYMS
c-3
ACMS
ADC
AIDS
APDM
APM
BCD
BITE
BNR
CMC
CRC
CW
DADC
DGNSS
ECEF
EGNOS
ETA
FAA
FAS
FASDM
FDE
FMC
FMS
FOM
GBAS
GLONASS
GLS
GNSS
GNSSU
GPS
HDOP
HFOM
HIL
ICAO
IRS
IRU
LAAS
LNA
LRU
MCU
MLS
MMR
MOPS
MTBF
MTBUR
NM
NVM
OMD
OMS
PAN
PRAIM
PRN
PVT
RAIM
SA
SATCOM
SBAS
SCAT
SDI
SSM
SV
SVID
TAS
Airplane Conditioning Monitoring System
Air Data Computer
Aircraft Integrated Data System
Airplane Personality Data Message
Airplane Personality Module
Binary Coded Decimal
Built In Test Equipment
Binary
Central Maintenance Computer
Cyclic Redundancy Check
Continuous Wave
Digital Air Data Computer
Differential GNSS
Earth Centered Earth Fixed
European Geostantionary Overlay System
Estimated Time of Arrival
Federal Aviation Administration
Final Approach Segment
Final Approach Segment Data Message
Fault Detection and Exclusion
Flight Management Computer
Flight Management System
Figure of Merit
Ground Based Augmentation System
Global Orbiting Navigation Satellite System
GNSS Landing System
Global Navigation Satellite System
Global Navigation Satellite System Unit
Global Positioning System
Horizontal Dilution of Precision
Horizontal Figure of Merit
Horizontal Integrity Limit
International Civil Aviation Organization
Inertial Reference Unit
Inertial Reference Unit
Local Area Augmentation System
Low Noise Amplifier
Line Replaceable Unit
Modular Concept Unit
Microwave Landing System
Multi-Mode Receiver
Minimum Operational Performance Standards (RTCA)
Mean Time Between Failure
Mean Time Between Unscheduled Removal
Nautical Mile
Nonvolatile Memory
Onboard Maintenance Document
Onboard Maintenance System
Precision Approach Navigator
Predicative Receiver Autonomous Integrity Monitoring
Pseudo Random Noise
Position, Velocity, Time
Receiver Autonomous Integrity Monitoring
Selective Availability
Satellite Communication
Satellite Based Augmentation System
Special Category
Source /Destination Indicator
Sign/Status Matrix
Satellite Vehicle
Satellite Vehicle Identification
True Airspeed
ARINC CHARACTERISTIC 743A - Page 73
APPENDIX F
GLOSSARY OF ABBREVIATIONS AND ACRONYMS
UDRE
URA
UTC
VDOP
VFOM
VIL
VSWR
WAAS
User Differential Range Estimate
User Range Accuracy
Universal Time Coordinated
Vertical Dilution of Precision
Vertical Figure of Merit
Vertical Integrity Limit
Vertical Standing Wave Ration
Wide Area Augmentation System
c-3
Copyright© 1993 by
AERONAUTICAL RADIO, INC.
2551 Riva Road
Annapolis, Maryland 21401-7465
SUPPLEMENT 1
TO
ARINC CHARACTERISTIC 743A©
GNSS SENSOR
Published: November 8, 1993
Prepared by the Airlines Electronic Engineering Committee
Adopted by the Airlines Electronic Engineering Committee: October 20, 1993
SUPPLEMENT 1 TO ARINC CHARACTERISTIC 743A - Page 2
A.PURPOSE OF THIS SUPPLEMENT
4.3.6 Differential GPS
This Supplement introduces revised selectivity criteria and
expands the definition of differential correction formats.
Additional changes were made to clarify portions of the
Characteristic which are directly impacted by new
applications envisaged for the GNSS Sensor.
The main title was changed to specify the focus on GPS
only.
This section was revised in anticipation of
implementation of differential GPS. A detailed description
of the differential function was added in Appendix A
pending completion of international standards.
B. ORGANIZATION OF THIS SUPPLEMENT
4.3.7 Differential GLONASS
The first part of this document, printed on goldenrod paper,
contains descriptions of changes introduced into this
Characteristic by this Supplement. The second part consists
of replacement white pages for the Characteristic, modified
to reflect the changes. The modified and added material on
each page is identified by a c-1 symbol in the margins.
Existing copies of ARINC Characteristic 743A may be
updated by simply inserting the replacement white pages
where necessary and destroying the pages they replace. The
goldenrod pages are inserted inside the rear cover of the
Characteristic.
New section was added to provide a dedicated section for
the differential GLONASS description when it becomes
available. The new text was derived from the former
section 4.3.6.
C. CHANGES TO ARINC CHARACTERISTIC 743A
INTRODUCED BY THIS SUPPLEMENT
Text was revised to the following: The GNSS SU should
be capable of accepting differential information which
should be available in the future. The differential interface
may be high or low speed and should be configured to
automatically sense and adjust to the input speed.
This section presents a complete tabulation of the changes
and additions to the Characteristic introduced by this
Supplement. Each change or addition is defined by the
section number and the title. In each case a brief
description of the change or addition is included.
The phrase “GPS/GLONASS” was changed to “GNSS”
throughout the document where appropriate.
1.2.1 Operational Consideration
In second paragraph, “initiation” was changed to
“navigation”, “in acceptable positions” was changed to
“tracked”, and “and pressure altitude has been calibrated to
GPS altitude” was added to the end of the paragraph.
“Geometrically” was changed to “geometry.”
1.3.1 GNSS Sensor Functions
In the section addressing ACQUISITION, the phrase “to
perform satellite range and range rate data processing” was
deleted.
2.2.5 Data Loader
New section added to introduce a data loader interface. The
following text was added:
“The GNSS SU should be compatible with a data loader
unit defined by ARINC Report 615. The input to the GNSS
SU should be through the use of the pins designated in
Attachment 3-2 “Standard Interwiring” of this
Characteristic. The output from the GNSS SU to the data
loader should be from any of the three ARINC 429 data
output ports specified in the Standard Interwiring. The
communication with the data loader should be activated by
the assigned discrete input pin.”
4.4.1.2 Inertial Inputs
The following text was deleted:
computations.”
“of moment arm
4.4.1.6 Differential Input
COMMENTARY
Two ARINC 429 input ports are needed for the
differential interface. The interface should support a
file-oriented ARINC 429 block transfer which does not
require any replay or handshake from the GNSS SU.
High-speed operation is strongly recommended for the
differential interface. However, low speed operation
should be supported for compatibility with existing
airframe equipment designs.
4.4.2.1 GNSS Measurement Status (60)
The phrase “satellite system” was added after “satellite
status.”
4.4.2.2 SSM Operation
The sentence beginning with “Attachment 4-4...” was
replaced with “Attachment 4-4 provides a list to indicate the
status of the sensor using the 2 bits of the SSM coding. The
2 bits should be set according to the above table to indicate
the status of the sensor. For example: For label 150, a
VALID status is indicated by NORM with bits 31-30
encoded as 1 and 1. In the ACQUISITION mode, NCD
code should be used by placing bit values 0 and 1 in bits 31
and 30 respectively.”
4.4.3
Discrete Inputs
Item “c” was revised from “GPS Deselect” to “Data Loader
Discrete.” The coding for the pin was set to “Open =
Normal and Ground = Data Loader Mode.”
3.3.1 Differential GPS Capabilities
New section added.
Item “d” was changed to “Air/Ground Discrete.” “Groundon-Ground” was added as the state descriptor.
SUPPLEMENT 1 TO ARINC CHARACTERISTIC 743A - Page 3
4.5.3 In-Band
Interference
Configuration)
Rejection
(2
MCU
4.6.3
In-Band
Interference
Configuration)
Rejection
(Alternate
The following text replaces the original text:
The following text replaces the original text:
After steady state navigation has been established, the
sensor unit should acquire and maintain code and carrier
lock of a GPS signal at -121 dBm in the presence of an inband interfering signal in the frequency range of 1575.42
±15 Mhz that is not more than the following levels as a
function of interfering signal bandwidth:
After steady state navigation has been established, the
sensor unit should acquire and maintain code and carrier
lock of a GPS signal at -136 dBm in the presence of an inband interfering signal in the frequency range of 1575.42
±15 MHz that is not more than the following levels as a
function of interfering signal bandwidth BW:
0 £ BW £ 500 Hz
600 Hz BW £ 1 kHz
1 kHz BW £ 10 kHz
10 kHz < BW £ 100 khz
100 kHz < BW
0 £ BW £ 600 Hz
600 Hz < BW £ 1 kHz
1 kHz < BW £ 10 kHz
10 kHz < BW £ 100 kHz
100 kHz < BW
-111 dBm
-106 dBm
-106+6log10(BW/1000)dBm
-00+3*log10(BW/10000)dBm
-97 dBm
-126 dBm
-121 dBm
-121+6*log10(BW/1000)dBm
-15+3*log10(BW/10000)dBm
-112 dBm
After steady state navigation has been established, the
sensor unit should acquire and maintain code and carrier
lock of a GLONASS signal at -122 dBm in the presence of
an in-band interfering signal in the frequency range of
1602-1616 MHz that is not more than the following levels
as a function of interfering signal bandwidth:
After steady state navigation has been established, the
sensor unit should acquire and maintain code and carrier
lock of a GLONASS signal at -137 dBm in the presence of
an in-band interfering signal in the frequency range of
1602-1616 MHz that is not more than the following levels
as a function of interfering signal bandwidth:
0 £ BW £ 100 Hz
100 Hz < BW £ 600 Hz
600 Hz < BW
0 £ BW £ 100 Hz
100 Hz < BW £ 600 Hz
600 Hz < BW
-105 dBm
-105+6.425*log10(BW/100)dBm
-100 dBm
All values are measured at the input to the sensor unit.
All values are measured at the input to the sensor unit.
COMMENTARY
COMMENTARY
The above numbers are based on maximum cable loss
and minimum preamplifier gain. The sensor should
maintain this performance at minimum cable loss and
maximum preamplifier gain.
The above numbers are based on maximum cable loss.
The sensor should maintain this performance at
minimum cable loss.
4.6.4
4.5.4 Out-of-Band
Signal
Configuration)
Rejection
-120 dBm
-120+6.425*log10(BW/100dBm
-115 dBm
(2
MCU
The following text replaces the original text:
The sensor should meet its performance requirements in the
presence of a CW signal which does not exceed the levels
shown in Attachment 5-1.
The sensor should meet its performance requirements when
multiple carriers exists in the SATCOM band (1626.51660.5 MHz) that can generate intermodulation products of
7th order or high in the GNSS band (1560-1617 MHz).
Out-of-Band
Signal
Configuration)
Rejection
(Alternate
The following text replaces the original text:
The signal rejection envelope shown in Attachment 5-2
takes into account a needed isolation of 40 dB between the
SATCOM antenna and the GNSS antenna in accordance
with section 5.5.2.
The sensor should meet all its performance requirements
when multiple carriers exist in the SATCOM band (1626.51660.5 MHz) that can generate intermodulation products of
7th order or high in the GNSS band (1560-1617 MHz).
The signal rejection envelope shown in Attachment 5-1
takes into account a needed isolation of 40 dB between the
SATCOM antenna and the GNSS antenna connector, in
accordance with paragraph 5.5.2.
The signal rejection envelope shown in Attachment 5-3 is
considered feasible for isolation from the lower end of the
SATCOM bank (1626.5). This assumes a nominal 160
inches of separation between the GPS and SATCOM low
gain antenna on an aluminum fuselage with a nominal
isolation of -39 dB to -44 dB provided by the GNSS
antenna connector. The installation should consider the
isolation characteristics of the specific equipment and
airframe antenna installations for best results.
4.6.1 Acquisition Sensitivity (Alternate Configuration)
5.4.3 Preamplifier Selectivity
In the sentence beginning with “When a satellite...”, the
phrase “for less than one minute” was added after “vehicle
shadowing.”
The second paragraph was revised to:
Re-acquisition time was changed from “15 seconds” to “5
seconds.”
The signal rejection envelope shown in Attachment 5-3
takes into account a needed isolation of 40 dB between the
SATCOM antenna and the GNSS antenna in accordance
with Section 5.5.2.
SUPPLEMENT 1 TO ARINC CHARACTERISTIC 743A - Page 4
5.5.2 Installation (2 MCU Configuration)
ATTACHMENT 1 - GNSS SENSOR UNIT SIGNAL
INPUT/OUTPUT SCHEMATIC
The following paragraph was added just before the
Commentary:
The number was changed from “1-2” to “1.”
The antenna/preamplifier/filter assembly should be installed
to provide a minimum of 10.5 dB (40 dB isolation minus
29.5 dB gain) of isolation from all L band antennas, in
particular the SATCOM antennas, at the GNSS and
SATCOM operating frequencies measured at the
antenna/preamplifier/filter connector.
A Data Loader input was added.
An Air/Ground Discrete was added.
The Integrity Monitor Input was removed.
A second differential input was added.
The Commentary was revised to the following:
Maintenance interface was changed to an input only.
COMMENTARY
The GNSS antenna/preamplifier/filter assembly should
be located on the forward part of the fuselage (on or
close to the top centerline) to minimize shadowing by
the vertical stabilizer, wing multi-path and shadowing
by the wing during all maneuvers.
Certain antenna installations require corrosion
protection in the form of a dielectric corrosion inhibitor
between the fuselage and the antenna baseplate. In this
situation the only bonding path is through the mounting
screws. In order to attain proper bonding, the antenna
mounting screw hole countersink must be such that the
installed screw head is in contact with the bare metal of
the baseplate.
6.3.2 Installation (Alternate Configuration)
The following paragraph was added just before the
Commentary:
The antenna should be installed to provide a minimum of 40
dB of isolation from all L band and VHF antennas, in
particular the SATCOM antennas, at the GNSS operating
frequencies measured at the antenna connector.
The Commentary was revised to the following:
COMMENTARY
The antenna(s) should be located on the forward part of
the fuselage (on or close to the top centerline) to
minimize shadowing by the vertical stabilizer, wing
multi-path and shadowing by the wing during all
maneuvers.
Certain antenna installations require corrosion
protection in the form of a dielectric corrosion inhibitor
between the fuselage and the antenna baseplate. In this
situation the only bonding path is through the mounting
screws. In order to attain proper bonding, the antenna
mounting screw hole countersink must be such that the
installed screw head is in contact with the bare metal of
the baseplate.
ATTACHMENT
1-1
INTERCONNECT ARCHITECTURE
The entire drawing was deleted.
GPS/GLONASS
ATTACHMENT 3-1 - STANDARD INTERWIRING - 2
MCU CONFIGURATION
Notation of ARINC 429 pins changed from “H and L” to
“A and B” respectively.
Pin assignment for 03A changed to “429 IN DIFF #1(A)”
Pin assignment for 03B changed to “429 IN DIFF #1(B)”
Pin assignment for 03C changed to “429 IN DIFF #2(A)”
Pin assignment for 03D changed to “429 IN DIFF #2(B)”
Pin assignment for 05D changed to “SPARE”
Pin Assignment for 07C changed to “Data Loader Mode
Discrete”
Pin assignment for 07D changed to “Air/Ground Discrete”
Pin assignment for 09A changed to “Data Loader In(A)”
Pin assignment for 09B changed to “Data Loader In(B)”
ATTACHMENT 3-2 - STANDARD INTERWIRING ALTERNATE CONFIGURATION
The “H and L” on two-wire interfaces were changed to “A
and B” respectively.
“From CMC” was added to pins 31-32.
Pin assignment for 04 changed to “DATA LOADER
IN(A)”
Pin assignment for 15 changed to “DATA LOADER
IN(B)”
Pin assignment for 05 and 06 interchanged. 05 is SDI 2
Pin assignment for 12 changed to “Data Loader Mode
Discrete”
Pin assignment for 16 changed to “429 IN DIFF #2 (A)”
Pin assignment for 17 changed to “429 IN DIFF #2 (B)”
Pin assignment for 23 changed to “429 IN DIFF #1 (A)”
Pin assignment for 28 changed to “AIR/GROUND
DISCRETE”
Pin assignment for 41 changed to “429 IN DIFF #1 (B)”
The note addressing pins 23 and 24 was deleted.
The above pin assignments were also changed for the
Standard Interwiring. The Standard Interwiring includes
the following additional changes for the “aircraft side” of
the connection:
04
15
16
17
23
41
-From Data Loader
-From Data Loader
-From Differential Source
-From Differential Source
-From Differential Source
-From Differential Source
SUPPLEMENT 1 TO ARINC CHARACTERISTIC 743A - Page 5
ATTACHMENT 4-1 - ARINC 429 INPUTS FOR GNSS
The following note was added to the page:
NOTE: Label 201 is used for the System Address Label.
See ARINC Specification 429 for details regarding its use.
“BIN” was changed to “BNR.”
ATTACHMENT 4-2 - ARINC 429 OUTPUTS FOR
GNSS
Sig. bits was changed to 5 for label 125.
For labels 065, 066, 070, 071, 072, 073, and 137, the
superscript “7” was replaced by “*****.”
Label 137 was assigned to “User Rage Accuracy.” It will
be a BNR word with meters as the units. It will use 17
significant bits to provide a range of 8192 with 0.0625
resolution.
For labels 060, 061, 062, 063, 064, 065, 066, 070, 071,
072, 073, and 074, the Max Transport Delay was changed
from “100” to “200.”
In note 4, the text was revised as follows: “The integration
time for the integrated delta range should be 1 second. The
delay range measurement valid time should be the time
specified in label 074 (end of integration time).”
A new note 8 was added: “If differential corrections are
being used, the raw data measurement block parameters
should be corrected with the differential corrections. The
method of correction should be based on the differential
GNSS method being used.”
In note 9 (new note #) the text was revised to “Bit 11 of
label 130 should be set to “1” whenever the receivers’
RAIM detects a satellite failure and should be set to “0” at
all other times.
ATTACHMENT 4-3 - DISCRETE ARINC 429 (INPUT)
DEFINITION
The word “INPUT” in title was changed to “OUTPUT”
when appropriate.
The format for the newly assigned word with label 355 was
added.
For label 060:
The Max Transmit (TX) Interval was changed from “1000”
to “1200” for all labels.
Label 130 was changed from “Autonomous Integrity Limit”
to “Horizontal Integrity Limit.” Bit 11 of the word will be
changed from LSB to a discrete bit. The resulting
resolution will be 0.0001221. The following note “#” will
be added: Bit 11 should be set to “1” whenever the
receiver's RAIM makes a satellite failure detection and
should be set to “0” at all other times. “18” was changed to
“17” for SIG BITS.
The superscript “##” was added to label 150. Note “##”
was added with following text: “Bit 11 of label 150 should
be encoded with a “1” when the GNSS system clock is
being used as the source of time. Otherwise bit 11 should
be encoded as “0.”
Bit 11 of label 060 was assigned to “Satellite System.” Bit
23 of label 060 was assigned to “SVID Status.”
The Valid and Invalid assignments were changed to 1 and 0
respectively.
For Label 355, Bits 23 and 24 clarified as referring to
FMS/IRS. Bits 22 and 21 clarified as referring to DADS.
Bits 19 and 20 changed to “Differential Inputs”, 1 and 2
respectively.
For label 275:
Bit 13 assignment was changed to “Differential Mode
Deselect” with the values “Deselect=1” and “Select=0.”
ATTACHMENT 4-4 - ARINC 429 SSMs FOR GNSS SU
Label 165 Range was corrected from 37268 to 32768.
In note *, the text was revised to the following: “Time is in
milliseconds. Nominal transmit interval is expected to be
1000 milliseconds.”
In note **, the text was revised to the following: “Output
rate per satellite. (The satellite measurement block should
be output once per each tracked satellite. The satellite
measurement block should be gin with measurement status
and end with User Range Accuracy. The maximum number
of satellite measurement blocks which can be transmitted in
one second is 32.) The maximum transport delay of the SV
measurements are applicable to high speed outputs only.”
The phrase “Altitude/Clock” will be added in note “*”
between “the” and “AIDED.”
Label 130 was renamed to “Horizontal Integrity Limit”
using the same assignments as Label 136.
Label 133 was assigned as “Vertical Integrity Limit” using
the same assignments as Label 136.
“NCO” was changed to “NCD” for labels 121 and 174.
“NCD” was changed to “NORM” for label 141 in the >
16NM column.
In note *****, “GPS” was removed and “he” was corrected
to “the.” The sentence was ended with “:”.
Label 137 User Range Accuracy was added.
parameters are “TEST N/A NORM NORM FAIL.”
In note 2, the phrase “When not corrected within the
differential mode”, was added to the beginning of the note.
The reference was corrected to “ICD-GPS-200.”
The note “**” was added to each of the following labels:
130, 133, 136 and 247 as follows: “In addition to the
situation of a normal NCD where there exists an inadequate
constellation configuration, the SSM should be set to NCD
when the calculated values exceed their respective
maximum range definition in Attachment 4-2.”
In note 3, the text was changed to “...the warning bit (19)
should...”. “GPS” was changed to “Sensor.”
The
SUPPLEMENT 1 TO ARINC CHARACTERISTIC 743A - Page 6
ATTACHMENT 4-5 - DIFFERENTIAL GPS MESSAGES
The material was corrected for minor typographical errors
and moved to Appendix A.
ATTACHMENT 5-1 - MCU CONFIGURATION CW
SIGNAL REJECTION
Attachment revised to reflect new selectivity criteria.
Section title was changed to “2 MCU Configuration
Interference Level.”
ATTACHMENT 5-2 - ALTERNATE CONFIGURATION
SIGNAL REJECTION
Attachment revised to reflect new selectivity criteria.
Section title was changed to “Alternate Configuration
Interference Level.”
APPENDIX A - DIFFERENTIAL
WILLIAMSBURG PROTOCOL
New Appendix added.
GPS
USING
Copyright© 1995 by
AERONAUTICAL RADIO, INC.
2551 Riva Road
Annapolis, Maryland 21401-7465 USA
SUPPLEMENT 2
TO
ARINC CHARACTERISTIC 743A
GNSS SENSOR
Published: December 31, 1995
Prepared by the Airlines Electronic Engineering Committee
Adopted by the Airlines Electronic Engineering Committee: November 2, 1995
SUPPLEMENT 2 TO ARINC CHARACTERISTIC 743A - Page 2
A. PURPOSE OF THIS DOCUMENT
4.4.2.3 Navigation Data Block
This Supplement introduces changes to the Global
Navigation Satellite Services (GNSS) Sensor to better
define the sensor in-band signal rejection performance with
and without the Aeronautical Mobile Satellite Service
(AMSS) and reference TSO C-129 for predictive RAIM.
Attachments 4-1, 4-1A, 4-2, 4-2A (notes), 4-2B, 4-2C
(notes), and 4-4 were changed to assign ARINC 429
input/output labels for the predictive RAIM function.
Attachments 5-1 and 5-2 were updated to include new
interference level curves for the 2 MCU configuration
GNSSU. Attachments 5-4 and 5-5 were added to provide
interference level curves for the alternate configuration
GNSSU. Appendix A was changed to a definition of the
DGPS Broadcast protocol. Appendix B was added as a
place-holder for the Wide Area Augmentation System
(WAAS). Appendix C was added for the predictive RAIM
as an option.
A new section was added to define the Navigation block as
a set of labels.
B. ORGANIZATION OF THIS SUPPLEMENT
The first part of this document, printed on goldenrod paper
contains descriptions of changes introduced into this
Characteristic by this Supplement. The second part consists
of replacement white pages for the Characteristic, modified
to reflect the changes. The modified and added material on
each page is identified by a c-2 in the margins. Existing
copies of ARINC Characteristic 743A may be updated by
simply inserting the replacement white pages where
necessary and destroying the pages they replace. The
goldenrod pages are inserted inside the rear cover of the
Characteristic.
C. CHANGES TO ARINC CHARACTERISTIC 743A
INTRODUCED BY THIS DRAFT SUPPLEMENT
This section presents a complete tabulation of the changes
and additions to the Characteristic to be introduced by this
Supplement. Each change or addition is defined by the
section number and the title that will be employed when the
Characteristic is eventually incorporated. In each case a
brief description of the change or addition is included.
4.4.3 Discrete Input
Item e was expanded to state that Bits 10 and 9 should be
encoded as SDI bits.
The functions for MP5A/pin 5 and MP5B/pin 36 were
listed herein for convenience.
The Commentary was deleted consistent with the deletion
of label 275 (the GNSS System Deselect label).
4.5 Sensor Performance (2MCU Configuration)
A Commentary was added to explain that GNSSUs used for
more demanding applications may have to comply with
additional interference requirements.
Text was added stating that the figures may change as
satellite systems evolve.
4.5.3 In-Band Signal Rejection (2 MCU Configuration)
This section was modified in its entirety.
4.5.6.1 Connector (2 MCU Configuration)
The existing text was replaced by that defining the
frequency range for the size 5 coaxial connector.
4.6 Sensor Performance (Alternate Configuration
A Commentary was added as stated in 4.5 above.
4.6.3 In-Band Signal Rejection (Alternate Configuration)
This section was modified in its entirety.
ATTACHMENT 4-1 ARINC 429 INPUTS FOR GNSS
1.2.3 Predictive RAIM
A new section was added to reference Appendix C which
describes the RAIM capability. A Commentary is included
stating that for certain TSO C-129 classes, predictive RAIM
may be included within the aircraft sensor unit.
4.3.6 Differential GPS
A Commentary was added cautioning manufacturers when
to apply ionospheric and tropospheric corrections.
4.4.2.1 GNSS Measurement Status (060)
The reference to Attachment 4-2B was corrected.
4.4.2.2 SSM Operation
Appropriate notes were applied to labels 040, 041, and 042.
Labels 045, 046, 124, 143, 144, 146, 152, 167, 170, 171,
204, 210, 216, and 227, were assigned.
Label 275 was deleted.
To avoid possible conflict between a note notation and a
bus number, all notes were changed from numbers
designation to letters designation, e.g., “note 1” was
changed to “note a”, “note 2” to “note b”, etc.
The SIG BITS for labels 146, 170 and 203 were corrected
to “17” versus “20.” The resolution for label 203 was
corrected to 1 FT.
The first word in the titles for labels 167, 214 and 216 were
changed to “Alt Waypoint.”
This section was modified by deleting the second and third
sentences beginning with “As a result of.” The SSM
encoding table was deleted, also.
The units for labels 167 and 152 were corrected.
The definition was expanded to allow for means other than
the GIC.
The title of label 227 was changed to “BITE Command”
with bus #8 and appropriate parameters entered in the
columns.
SUPPLEMENT 2 TO ARINC CHARACTERISTIC 743A - Page 3
Labels 203, 204, 210 and 212 were assigned for ARINC
419 inputs. Appropriate notes were applied to labels 260,
310, 311, 312, 313, 314, 320, 324, 325, 361, and 365.
ATTACHMENT
5-2
GPS/GLONASS
2
CONFIGURATION INTERFERENCE LEVEL
MCU
ATTACHMENT 4-1A NOTES FOR ARINC 429 INPUTS
A new curve was added depicting the expected interference
level for the 2 MCU GPS/GLONASS configuration.
This attachment was added providing notes to explain the
new labels and to better define some of the existing labels.
ATTACHMENT 5-4 GPS ALTERNATE
CONFIGURATION INTERFERENCE LEVEL
ATTACHMENT 4-2 GNSSU ARINC 429 OUTPUT
DATA
A new curve was added depicting the expected interference
level for the alternate GNSS Sensor configuration.
Labels 057, 124, 126, 127, 143, 144, 155, 156, 157, 162,
163, 226, 273, 343, 344, 346, 347, 352, 355, and 356 were
assigned.
ATTACHMENT 5-5 GPS/GLONASS ALTERNATE
CONFIGURATION INTERFERENCE LEVEL
All number designations for the notes were changed to letter
designations.
A new curve was added showing the expected interference
level for the GPS/GLONASS alternate configuration.
APPENDIX A DIFFERENTIAL CORRECTIONS
Note (e) was applied to label 057.
This appendix was changed in its entirety to define the
DGPS Broadcast protocol.
Note (f) was applied to label 150.
ATTACHMENT 4-2A NOTES FOR GNSS ARINC 429
OUTPUTS
This attachment was added providing notes to describe the
GNSSU ARINC 429 output labels.
APPENDIX B
WIDE AREA AUGMENTATION
SYSTEM PROVISIONS
This appendix was added and is a place-holder for the
WAAS provisions.
APPENDIX C PREDICTIVE RAIM CAPABILITY
ATTACHMENT
4-2B
ARINC
429
MEASUREMENT STATUS (LABEL 060)
GNSSU
This attachment was Attachment 4-3, formerly. It defines
the bit structure for label 060.
The note was corrected to read: “Bit 23 of label 060 should
be set to zero (invalid) when an erroneous satellite is
isolated and removed from the solution (due to malfunction
or RAIM detection).”
ATTACHMENT 4-2C ARINC 429 GNSSU SENSOR
(LABEL 273)
This attachment was Attachment 4-3, formerly. It provides
the Bit structure for label 273 which was previously
omitted. Previous definition for label 275, was deleted.
ATTACHMENT 4-3 DISCRETE ARINC 429 INPUT
DEFINITION FOR GNSS SENSOR
This attachment was deleted by Supplement 2.
ATTACHMENT 4-4 ARINC 429 SSMs FOR GNSSU
SENSOR
This table was modified to delete label 137 and add labels
057, 124, 126, 127, 143, 144, 155, 156, 157, 162, 163,
226,343, 344, 346, 347, 352, 354, 355, and 356. Clarifying
notes were corrected and added, also.
ATTACHMENT 5-1 GPS 2 MCU CONFIGURATION
INTERFERENCE LEVEL
A new curve was added depicting the expected interference
level for the 2 MCU GNSS Sensor configuration.
This appendix was added to define the predictive RAIM
capability, as an option.
Copyright© 1998 by
AERONAUTICAL RADIO, INC.
2551 Riva Road
Annapolis, Maryland 21401-7465
SUPPLEMENT 3
TO
ARINC CHARACTERISTIC 743A©
GNSS SENSOR
Published: January 5, 1998
Prepared by the Airlines Electronic Engineering Committee
Adopted by the Airlines Electronic Engineering Committee: October 15, 1997
SUPPLEMENT 3 TO ARINC CHARACTERISTIC 743A - Page 2
A. PURPOSE OF THIS DOCUMENT
4.3 Modes
This Supplement introduces changes to the Global
Navigation Satellite System (GNSS) Sensor to define the
Wide Area Augmentation System (WAAS) and the Local
Area Augmentation System (LAAS) interfaces and
approach operation modes.
Text was added to this section to define the GNSS function
operating in the Acquisition Mode.
B. ORGANIZATION OF THIS SUPPLEMENT
The first part of this document, printed on goldenrod paper,
contains descriptions of changes introduced into this
Characteristic by this Supplement. The second part consists
of replacement white pages for the Characteristic, modified
to reflect the changes. The modified and added material on
each page is identified by a “c-3” in the margins. Existing
copies of ARINC Characteristic 743A may be updated by
simply inserting the replacement white pages where
necessary and destroying the pages they replace. The
goldenrod pages are inserted inside the rear cover of the
Characteristic.
4.3.1 Normal Acquisition
The second paragraph was modified to improve readability.
Text was added to state that all labels should be set
appropriately when the GNSSU is in the Acquisition Mode.
4.3.2 Abnormal Acquisition
Text was inserted to clarify that available satellites will be
used.
4.3.3 Navigation
The definition of this mode was expanded for clarity.
4.3.4 Altitude/Clock Aiding Mode
C. CHANGES TO ARINC CHARACTERISTIC 743A
INTRODUCED BY THIS DRAFT SUPPLEMENT
This section was modified by clarifying the use of the
altitude and clock aiding mode.
This section presents a complete tabulation of the changes
and additions to the Characteristic to be introduced by this
Supplement. Each change or addition is defined by the
section number and the title that will be employed when the
Supplement is eventually incorporated. In each case a brief
description of the change or addition is included.
4.3.5 Aided Mode
1.2.3 Differential Corrections
The section and its subordinate sections were changed to
describe SCAT I and LAAS provisions.
The definition was expanded to explain that the aided mode
can be entered from the NAV mode.
4.3.6 Ground Based Augmentation System (GBAS)
A reference to Appendix A was added.
4.3.8 Satellite Based Augmentation System (SBAS)
1.2.4 Wide Area Augmentation System Provisions
A reference to Appendix B was added.
This section and its subordinate sections were added to
define the satellite based mode, which consists of the
WAAS interface.
1.2.5 Predictive RAIM
4.3.9 Self Test Mode
This section was renumbered.
1.2.6 Airplane Personality Data Message (APDM)
This section was added to define the Self Test mode of
operation.
A reference to Appendix D was added.
4.3.10 Initialization Mode
1.2.7 Final Approach Segment (FAS) Data Message
(FASDM)
This section was added to define the Initialization mode.
4.3.11 Fault Mode
A reference to Appendix E was added.
This section was added to define the Fault mode.
3.3 General System Capabilities
4.4.2.1 GNSS Measurement Block
This section was expanded to describe WAAS and LAAS
as two means of Augmentation.
This section was added to define output data for each
satellite tracked.
3.3.1 Differential GNSS (DGNSS) Capabilities
This section was updated to reference RTCA DO-217, the
MASPS for SCAT I. Definition of the differential
corrections measurement was improved.
A Commentary was added.
4.5 Sensor Performance (2 MCU Configuration)
This section and several of its subsections were revised
consistent with the antenna and WAAS MOPSs (RTCA
DO-228 and DO-229).
SUPPLEMENT 3 TO ARINC CHARACTERISTIC 743A - Page 3
4.5.1 Acquisition Sensitivity (2 MCU Configuration)
4.6.3 In-Band Signal (Alternate Configuration)
The sensor carrier-to-noise ratio was changed to 36 dBm
for consistency. A Commentary was added explaining
that GPS signals can be acquired or reacquired at the
interference level stated in this section.
This section was reorganized and modified to replicate
the 2 MCU configuration.
4.5.3 In-Band Signal Rejection (2 MCU Configuration)
4.6.3.1 With Aeronautical Mobile Satellite Service
(AMSS) on Same Aircraft (Alternate
Configuration)
This section was expanded to define the sensor tracking
performance, consistent with the antenna and WAAS
MOPSs.
This section was modified to replicate the 2 MCU
configuration.
4.5.3.1 Pulse Signal Rejection (2 MCU Configuration)
4.6.3.2 Without Aeronautical Mobile Satellite Service
(AMSS) on Same Aircraft (Alternate
Configuration)
This section was condensed to specify the frequency
range and refer to Section 4.5.3 for details.
4.5.3.2 Without Aeronautical Mobile Satellite Service
(AMSS) on Same Aircraft (2 MCU
Configuration)
This section was condensed to specify the signal tracking
performance and refer to the WAAS MOPS for
equipment classes.
This section was modified to replicate the 2 MCU
configuration.
4.6.3.3 Pulse Signal Rejection (Alternate Configuration)
This section was modified to replicate the 2 MCU
configuration.
4.6.4 Out-of-Band Signal Rejection (Alternate
Configuration)
4.5.3.3 Pulse Signal Rejection (2 MCU Configuration)
The peak power and pulse width specifications were
changed and Commentary was added for clarity.
This section was modified to replicate the 2 MCU
configuration.
4.6.5 Burnout Protection (Alternate Configuration)
4.5.4
Out-of-Band Signal
Configuration)
Rejection
(2
MCU
Subsections were added to define the sensor performance
and antennas separation regarding the isolation level.
This section was modified to reduce the damage level to
20 dBm at the sensor antenna port.
4.6.6.2 Sensor
Input
Configuration
Impedance
(Alternate
4.5.5 Burnout Protection (2 MCU Configuration)
This section was modified to reduce the damage level to
20 dBm at the sensor antenna port.
4.5.6.2 Sensor Input Impedance
This section was modified to replicate the 2 MCU
configuration. The phrase regarding frequency range of
1609 ± 9 MHz was deleted.
4.6.6.3 Source Impedance and Stability (Alternate
Configuration)
The tolerance for the frequency range was increased.
4.5.6.3
Sensor Impedance and Stability (2 MCU
Configuration)
This section was modified to replicate the 2 MCU
configuration.
4.7 Location of the GNSS function
This section was modified to specify the frequency range
in which stability must be achieved.
This section was added to explain the possible locations
of the GNSSU functions.
4.5.6.4 Preamplifier Power (2 MCU Configuration)
5.1 Introduction
The tolerance on the preamplifier bias was increased to
20%. The current was reduced to 60 mA. The last
sentence regarding removal of power from the
preamplifier was deleted.
This section was added to specify RTCA DO-228 MOPS
and FAA TSO C-144.
4.6 Sensor Performance (Alternate Configuration)
5.2 Active Antenna Requirements
This section was modified to replicate the 2 MCU
configuration.
Text was added to specify RTCA DO-228 and TSO
C-144.
4.6.1 Acquisition Sensitivity (Alternate Configuration)
5.2.1 Preamplifier Gain
This section was modified to replicate the 2 MCU
configuration. The last sentence was deleted.
Text was added to better define the preamplifier gain.
SUPPLEMENT 3 TO ARINC CHARACTERISTIC 743A - Page 4
ATTACHMENT 4-2D - GNSS FAULT SUMMARY
FORMAT (LABEL 355)
5.2.2 Precipitation Static
This section was renumbered.
This attachment was added to define label 355, per
ARINC Characteristic 755.
5.2.3 Impedance and VSWR
The antenna VSWR was specified.
ATTACHMENT 4-2E - GNSS ARINC 429 OUTPUT
LABEL DEFINITION (LABEL 125)
5.2.4 Preamplifier Bias
This attachment was added to define label 125.
This section was renumbered. The tolerance on the
preamplifier bias was increased to 20%. The current was
reduced to 60 mA.
ATTACHMENT 5-1 - GPS 2 MCU ALTERNATE
CONFIGURATION INTERFERENCE LEVEL
5.3 Preamplifier Assembly Performance
The interference rejection curve was updated, consistent
with RTCA DO-228.
This section was renumbered.
5.3.1 Size, Weight and Connector
ATTACHMENT 5-2 - GPS/GLONASS 2 MCU
CONFIGURATION INTERFERENCE LEVEL
The maximum weight of the antenna was changed from 3
lbs. to 1 lb.
The interference rejection curve was updated, consistent
with RTCA DO-229.
5.3.2 Installation
ATTACHMENT 5-3 - FREQUENCY SELECTIVITY
This section was renumbered.
The interference rejection curve was updated, consistent
with RTCA DO-228 and renamed as shown.
The last sentence of the first paragraph was modified to
better define the gain of the antenna when coupled with
the LNA.
ATTACHMENT
5-4
GPS
ALTERNATE
CONFIGURATION INTERFERENCE LEVEL
ATTACHMENT 4-1 - ARINC 429 INPUTS FOR GNSS
This attachment was deleted, as Attachment 5-1 applies
to both the 2 MCU and Alternate configurations.
ARINC 429 labels 033, 232, 242, 243 and 244 were
added.
ATTACHMENT 4-2 - ARIINC 429 OUTPUT DATA
FOR GNSS
ARINC 429 labels 033 (MMR Tune), 105 (Runway
Heading), 172 (Distance to Threshold), 173 (LOC
Deviation), 227 (Slot Group ID), 240 (G/S Deviation),
263 (Approach ID 1), 264 (Approach ID 2), 370 (GNSS
Height), TBDX (Vertical GLS Dev Rectilinear), and
TBDY (Horizontal GLS Dev Rectilinear) were added.
ATTACHMENT
CATEGORIES
6
-
ENVIRONMENT
TEST
This attachment was updated, consistent with ARINC
Characteristics 755 and 756.
ATTACHMENT 9 - GNSS SIGNAL LOSSES
The upper part of the diagram was updated consistent
with RTCA DO-228.
ATTACHMENT 4-2A - NOTES FOR GNSS ARINC
429 OUTPUTS
ATTACHMENT 10 - MODE TRANSITION TABLE
Note k was added.
This table was added to describe the mode transitions and
the conditions which stimulate mode transitions.
ATTACHMENT 4-2B - ARINC 429
MEASUREMENT STATUS (LABEL 060)
GNSSU
ARINC 429 label 060 bit format was restructured,
consistent with ARINC Specification 429 and
Characteristic 755 format.
The bits definition and notes were modified per changes
to related text.
ATTACHMENT 4-2C - ARINC 429 SENSOR STATUS
(LABEL 273)
ARINC 429 label 273 bit format was restructured,
consistent with ARINC Specification 429 and
Characteristic 755 format.
APPENDIX B - WIDE AREA AUGMENTATION
SYSTEM PROVISIONS
This appendix was expanded to provide general and
design guidance for WAAS classes Beta-1 and Beta-2
sensors used to support en route, terminal and/or nonprecision approach phases of flight navigation.
APPENDIX D - AIRPLANE PERSONALITY DATA
MESSAGE (APDM)
This appendix was added and refers to ARINC
Characteristic 755 for a description of the message
communicated between the GNSSU and an external
device pertaining to airplane specific data.
SUPPLEMENT 3 TO ARINC CHARACTERISTIC 743A - Page 5
APPENDIX E - FINAL APPROACH SEGMENT
(FAS) DATA MESSAGE (FASDM)
This appendix was added and refers to ARINC
Characteristic 755 for a description of message
communicated between the GNSSU and an external
device pertaining to an approach to a particular runway.
APPENDIX F - GLOSSARY OF ABBREVIATIONS
AND ACRONYMS
A glossary was added for reader convenience.
Copyright© 2001 by
AERONAUTICAL RADIO, INC.
2551 Riva Road
Annapolis, Maryland 21401-7465
SUPPLEMENT 4
TO
ARINC CHARACTERISTIC 743A©
GNSS SENSOR
Published: November 29, 2001
Prepared by the Airlines Electronic Engineering Committee
Adopted by the Airlines Electronic Engineering Committee: October 24, 2001
SUPPLEMENT 4 TO ARINC CHARACTERISTIC 743A - Page 2
A. PURPOSE OF THIS SUPPLEMENT
1.3.1 GNSS Sensor Functions
This Supplement introduces revisions and additions to the
body and attachments of ARINC Characteristic 743A to
define two stand alone devices configuration. This
definition may also be referenced by other ARINC
Characteristics, which provide a GNSS function
integrated within.
The Note was deleted.
1.3.4 GNSS Sensor
The Commentary was revised deleting obsolete text.
1.8 Unit Identification
B. ORGANIZATION OF THIS SUPPLEMENT
The material in Supplement 4 is integrated into ARINC
Characteristic 743A to form an updated version of the
standard.
This section was added
identification number.
to
address
equipment
3.3 General System Capabilities
The changes introduced by Supplement 4 have been
identified using change bars and are labeled in the margin
with a “c-4” indicator.
The reference to SBAS and GBAS were added.
C. CHANGES TO ARINC CHARACTERISTIC 743A
INTRODUCED BY THIS SUPPLEMENT
Text was added to the first paragraph to refer SBAS to
RTCA document DO-229 and GBAS to RTCA document
DO-253. The 3rd and the 4th paragraphs were revised for
to clarify when GNSS should apply GBAS correction.
This section presents a complete tabulation of the changes
and additions to the Characteristic introduced by this
Supplement. Each change or addition is defined by the
section number and the title that will be employed when
the Supplement is eventually incorporated. In each case a
brief description of the change or addition is included.
3.3.1 Differential GPS Capabilities
4.2 Integrity
References to RTCA documents DO-208 and DO-229
were added.
1.1 Purpose of This Document
4.3 Modes
Text was added defining two stand alone devices
configuration that also referenced by other ARINC
Characteristics.
LAAS and WAAS were revised to GBAS and SBAS
respectively.
4.3.3 Navigation
1.2 Summary of GNSS System Operational Characteristics
The following text was added:
The reference to Position, Velocity, and Time was added.
Additionally, text was added stating the GNSS system
may utilize augmentation to enhance its operational
capability.
“The basic PVT data is provided in labels 110, 111, 112,
120, 121, 125, 150, 166, 174, 076, and 370.”
A Commentary was added referring to
measurement being integrated with inertial data.
The second paragraph was revised as follows:
satellite
1.2.1 Operational Consideration
The first paragraph was revised for clarity.
1.2.2 Integrity Monitoring
4.3.5 Aided Mode
“Aided mode is an optional mode. The PVT outputs,
including FOMs and integrity limits, should be set NCD
in the Aided mode. SV measurement data should
continue to be output as valid data. See Attachment 4-4
for details.”
The Commentary was expanded to include the URA
output in label 067.
The reference to SBAS and GBAS were added.
4.3.6.1 SCAT I Mode
1.2.6 Airplane Personality Data Message (APDM)
Deleted by Supplement 4.
Deleted by Supplement 4.
4.3.6.2. GBAS Nav
1.2.7
Final Approach Segment (FAS) Data Message
(FASDM)
Deleted by Supplement 4.
The first paragraph and Commentary were revised to
support differential operation using GBAS correction.
1.3 Brief Description of the System
A second Commentary was added for the GNSS function
internal to the MMR.
The Section was revised to clarify that a standalone GNSS
system may be in one of two configurations.
The last paragraph referring to GBAS mode within the
MMR was deleted.
SUPPLEMENT 4 TO ARINC CHARACTERISTIC 743A - Page 3
Deleted by Supplement 4.
frequency range of 1575.42 MHz ± 3.069 MHz, and no
worse than 4:1 in the extension of that spectrum to
1575.42 MHz ± 10 MHz.”
4.3.6.2.2 LAAS Precision Approach
4.5.6.4 Preamplifier Power (2 MCU Configuration)
Deleted by Supplement 4.
Preamplifier requirements were revised from 12Vdc
± 20%, 60 ma to 12 Vdc ± 20%, 100 ma.
4.3.6.2.1 LAAS Excluding Precision Approach
4.3.6.2.2.1 General Functional Requirements
4.7 Location of the GNSS Function
Deleted by Supplement 4.
Deleted by Supplement 4.
4.3.6.2.2.2 GLS with an External GNSSU
5.2 Active Antenna Requirements (GPS Only)
Deleted by Supplement 4.
The title was revised to indicate GPS Satellites only.
4.3.6.2.2.2.1 GLS with a Precision Approach Navigation
(PAN) Function External To the GNSSU
5.2.1
Deleted by Supplement 4.
The Commentary was revised to include parasitic losses.
4.3.6.2.2.2.2 GLS with a PAN Internal to the GNSSU
5.2.4 Preamplifier Bias
Deleted by Supplement 4.
Preamplifier requirements were revised from 12Vdc
± 20%, 60 ma to 12 Vdc ± 20%, 100 ma.
Preamplifier Gain
4.3.7 Differential GLONASS
Deleted by Supplement 4.
4.3.8.1. SBAS Nav
The first paragraph was revised to state that GNSSU may
optionally support differential operation using SBAS
correction.
5.3.2 Installation
This section was added by Supplement 4.
5.3.3 Coax Interface
This section was added clarify interface between
antenna/preamplifier and the GNSS receiver.
4.3.8.1.1 WAAS Precision Approach Mode
5.3.4 Environmental Conditions
Deleted by Supplement 4.
This section was added by Supplement 4.
4.3.8.1.2.1 WAAS Precision Approach Mode Precision
Approach Navigator Functionality
5.4 Antenna/Preamplifier/Filter
(GPS/GLONASS)
Deleted by Supplement 4.
The title was revised to indicate this section refers to both
GPS and/or GLONASS satellites.
4.3.10 Initialization mode
Table 4.3-1, GNSS Modes, Modes 5, 6, 9, and 10, were
revised to support GBAS and SBAS.
4.4.1.5 Integrity Input
Requirements
5.4.7 Preamplifier Bias
Preamplifier requirements were revised from 12Vdc
± 10%, 100 ma to 12 Vdc ± 20%, 100 ma.
Deleted by Supplement 4.
5.5 Physical Characteristics (GPS/GLONASS)
4.4.1.6 Differential Input
The title was revised to indicate this section refers to both
GPS and/or GLONASS satellites.
The text was expanded stating that the GNSS may be
capable of accepting external differential correction as an
option.
5.5.2 Installation
4.5.6.2 Sensor Input Impedance (2MCU Configuration)
Section was revised to refer to Section 5.3.2.
Section was revised as follows: “The sensor should
present a nominal 50 ohms impedance at the input to the
RF connector. The maximum VSWR seen looking into
the inputs should be no worse than 2:1 over the operating
5.5.3 Coax Interface
Section was revised to refer to Section 5.3.3.
SUPPLEMENT 4 TO ARINC CHARACTERISTIC 743A - Page 4
ATTACHMENT 1 GNSS SENSOR UNIT SIGNAL
INPUT/OUTPUT SCHEMATIC
APPENDIX A DIFFERENTIAL CORRECTION
The Appendix was moved to ARINC Characteristic 755.
The Integrity Monitoring input bus was deleted and the
DADS input bus was revised to DADS/FMS input bus to
be consistent with Attachment 4-1.
ATTACHMENT 3-1
CONFIGURATION
GNSS
SENSOR,
2
MCU
APPENDIX B – WIDE AREA AUGMENTATION
SYSTEM PROVISIONS
The following text was deleted:
The DADS input bus was revised to the DADS/FMS input
bus to be consistent with Attachment 4-1.
“The GNSS function should output the entire satellite
measurement block within 260 milliseconds of the end of
the measurement integration interval. Refer to Figure B1.”
ATTACHMENT
3-2
GNSS
ALTERNATE CONFIGURATION
UNIT,
The reference to LAAS and WAAS were revised to
GBAS and SBAS respectively.
The DADS input bus was revised to the DADS/FMS input
bus to be consistent with Attachment 4-1.
In Subsection 1.0, references to RTCA DO-229 future
activities under the Commentary and the AEEC staff Note
were deleted because they are obsolete.
SENSOR
ATTACHMENT 4-1 - ARINC 429 INPUT DATA FOR
GNSS
The table was revised and reformatted to separate,
Standard and Optional ARINC 429 labels.
ATTACHMENT 4-2 - ARINC 429 OUTPUT DATA
FOR GNSS
Attachment 4-2, entire Attachment was revised and
reformatted to separate, Standard and Optional ARINC
429 labels.
Note 11, a Commentary, was added to explain the
conversion of altitude, Height Above Ellipsoid (HAE) to
mean sea level.
Note 12, was added providing a definition for ARINC 429
label 057.
Labels 105, 172, 173, 263, 264 TBDx and TBDy were
deleted.
ATTACHMENT
DEFINITION
4-2A
-
ARINC
429
LABEL
Bit definitions for ARINC 429 labels 124, 237, and 370
were added.
ATTACHMENT
CATEGORIES
6
-
ENVIRONMENTAL
TEST
Attachment 6 was revised to reflect the new RTCA DO160D requirements.
ATTACHMENT 8 - GNSS TIME MARK
SU solution was corrected to SV Solution (Solution
Valid).
ATTACHMENT 9 GNSS SIGNAL LOSSES
The acceptable cable loss was changed from 3 to 13dB to
3 to 12 dB and from 6 to 16 dB to 6 to 15 dB.
ATTACHMENT 10 MODE TRANSITION
The Attachment was revised to remove the Precision
Approach Navigator requirements.
In Subsection 3.0, Integrity Monitoring, the reference to
WAAS Precision Approach was deleted.
In Subsection 4.1 inputs the last two paragraphs on
WAAS interface requirements were deleted as they were
considerate repetitive with RTCA DO-229.
In Subsection 4.2.3, Failure Warning Enunciation, the
following sentence was added to the third and fourth
paragraph:
“The time to alert is 8 seconds for beta sensors.”
APPENDIX D - AIRPLANE PERSONALITY DATA
MESSAGE (APDM)
The Appendix was deleted by Supplement 4.
APPENDIX E - FINAL APPROACH SEGMENT (FAS)
DATA MESSAGE (FASDM)
The Appendix was deleted by Supplement 4.