The Master Plan Study on the Development of the New CNS/ATM Systems in Cambodia, Lao PDR and Vietnam: Draft Final Report
Chapter 14
14.1
Road Map for Future Air Traffic Management
General
The Study Team drew up a road map for ATM in consideration of Study analyses conducted at
Work Stage A (Collection and Analysis of Data and Information) through the year 2025.
The goals of developing a Roadmap for future ATM include;
• To promote a modern, efficient and cost-effective international ATS route network linking
city-pairs in Europe, Asia and North America, taking into account the recognized
requirements of the airspace users, taking advantage of seasonal wind patterns, and
making use of space-based technology in accordance with the ICAO CNS/ATM system
concept.
• To promote efficient air traffic management and associated systems to improve safety,
increase capacity and enhance operational and economic efficiency.
• To promote the provision of sufficient capacity so as to make best use of Air Traffic
Management.
• To develop a coherent transition plan enabling a seamless migration of current aircraft
fleets to full CNS/ATM compliance on such routes in the future.
• To promote the establishment of the minimum number of suitably equipped Area Control
Centres (ACC) and an infrastructure adequate to provide the required air traffic services
along the proposed ATS route structure.
• To promote suitable financing and cost recovery mechanisms for the newly established
route system in accordance with the applicable ICAO provisions.
• To analyse the costs and benefits achieved by individual ATS routes of the newly
established route system to determine their eligibility for inclusion into the ICAO
Regional Air Navigation Plan.
• To promote the progress of Performance Based Navigation (PBN) which includes not only
RNAV/RNP, GNSS, but also more Direct Routing between city pairs.
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14.2
Introduction
The Study Team is now preparing our strategic CNS/ATM implementation plans for the
coming periods 2010-2015 and 2016-2025 in Cambodia, Lao PDR and Vietnam. To cope with
the future growth in Air Traffic regionally, and within these 3-countries, as well as overcoming
problems in the current Air Traffic Management (ATM) practices of Cambodia, Lao PDR and
Vietnam, Study Team analyzed and discussed various options for future ATM. Study Team,
encouraged by the consensus of these 3-countries, found that the most effective method to
achieve optimization of ATC practices and air traffic management, and enhance Aviation
Safety.
The continuing growth of aviation places increasing demands on airspace capacity and the need
for optimum utilization of available airspace. With these needs and increasing fuel costs and
higher concerns on aircraft/airport noise to the environment, aviation industry calls for new
navigation technologies and operation procedures to be implemented. In response, these
3-countries of Cambodia, Lao and Vietnam need to adopt conclusions to promote the more
efficient and collaborative use of airspaces and Air Routes. This will be supported by
ground-based and airborne technologies for Air Traffic Management (ATM). ICAO has
disaggregated the Air Navigation System into its seven ATM concept components for the
purpose of role identification. These seven concept components are:
• Airspace Organization and Management
• Aerodrome Operations
• Demand and capacity balancing
• Traffic synchronization
• Airspace user operations
• Conflict management
• ATM service delivery management
(1)
1)
2)
3)
4)
(2)
1)
2)
3)
4)
Operational ATM Targets:
To establish safer separation between Aircraft (Separation Assurance: Procedural, Radar,
ADS-C, ADS-B)
To establish safe separation between aircraft & terrain in all 3-countries (e.g. Safety Alert).
To protect aircraft from bad weather (WX Radar; Satellite WX, ARSR, PIREP).
To have a means for joint communications and delivery of messages between aircraft
and/or other related organizations (CPDLC, SSR, ATN or next generation networks).
Air Traffic Management Facility Plans:
Procedures to enable flights to fly with least restrictions according to their flight plans
(Trajectory-based flow; Flex Routes; Collaborative Decision Making (CDM)).
Expanding and unifying the airspaces for flight operations and better utilization of
resources (ASM, RVSM, B/RNAV/RNP-5, P-RNAV/RNP-1 eventually).
Taking advantage of aircraft navigational resources (FMS/RNP-5, RNP-1)
Adoption of standardized Precision Approach procedures at all international and most main
domestic airports (ILS, GBAS/LAAS, SBAS/MSAS, GPS, RNAV, RNP-1).
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5) Preparation for the procedures extending aids for ground movements and taxiing of the
aircraft in the airport (ADS-B). Note: these technologies will only be considered
when/where they enhance the transition to En-route environments.
6) Adopting or harmonizing the Aeronautical Information Systems (AIS) in all 3-countries
(e.g. ATIS, Automated AIP, World Airport Data Bases, etc.).
The following are acceptable road maps made up by the Team. Details such as present situation,
phased development plan are mentioned below.
2010
Short Term
2015
Long Term
2025
1. Improvement for ATM
(1) Improvement of
Communication
Function
Maintain Existing System
(2) Improvement of
Surveillance Function
Maintain Existing System
(3) Upgrading Data
Exchange Function
Maintain Existing System
(4) Transfer of Control
(AIDC)
(5) Air Traffic Incident
Reporting System,
Follow-up System
(6) Improvement of FDP
and RDP Interfaces
(7) Adding Radar Data
Sharing Function
Improvement of Communication Function (CPDLC, etc.)
Improvement of Surveillance Function (ADS-B, SSR-ModeS etc.)
Upgrading Data Exchange Function (AMHS)
Renewal of LoA,
Design, Installation, Trial of AIDC
(Maintain Existing System)
Implementation Transfer of Radar Control
Study
Introduction of System
Design, Installation, Trial of New
System
(Maintain Existing System)
Improvement of FDP and RDP Interfaces
Design, Installation, Trial of New
Function
Introduction of Radar Data Sharing Function
2. ASM and ATFM
Assign Position for ATFM and ASM, Training Supervisors and Training Liaison Officers
(Tentative Implementation)
(1) ATFM and ASM
in Cambodia and
Lao PDR
(2) ATFM and ASM
in Vietnam
Assign Position for Air Space Management, Training Liaison Officers
(Tentative Implementation)
Introduction of ATFM/ATM Automation
System
3. AIS
[Cambodia, Lao PDR]
(1) E-AIP, NOTAM and
International Data
Exchange Function
Introduction of Electronic System
Development of Electronic AIS System
(2) Development of
Electronic AIS
System (eTOD, etc.)
[Vietnam]
(1) Introduction of
Advanced Electronic
AIS
Introduction of Advanced Electronic System
Source: BPS
Figure 14.2.1
Road Map for Future Air Traffic Management
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14.3
Essential Improvements Needed for 3 Countries’ ATM
Essential improvements to be needed for Cambodian, Laotian and Vietnamese ATM are as
follows.
(1)
Limitation to the Operation of Air Traffic Management (ATM)
The communication between a pilot on en-route and an air traffic controller is usually carried
out by VHF-ER (Very High Frequency - Extended Range) and/or HF (High Frequency).
According to field observation carried out by the Team, the communication coverage of the
VHF-ER and HF is good enough for aircraft flying almost all 4 FIRs in 3 countries.
However, there are limitations to air-ground communication in terms of line trouble triggered
low reliability between ATC facility and communication site, decisive defect in coverage to
cope with oceanic flight, etc. Moreover, there would be some misunderstandings between a
pilot and an air traffic controller because current air-ground communication is implementation
by voice communication. The current voice environment will cause channel congestion and
communications errors. The more traffic volume increases, the move workload for a pilot and
an air traffic controller increases.
To determine the most appropriate solution of several issues mentioned above, it is suitable to
introduce CPDLC (Controller-Pilot Data Link Communication) which is recommended by
ICAO.
CPDLC is a data link application that allows for the direct exchange of text-based messages
between a controller and a pilot. CPDLC greatly improves communication capabilities in
oceanic areas, especially in situations where controllers and pilots have previously had to rely on
a HF communications relay. Apart from the direct link, CPDLC adds a number of other benefits
to the ATS system, such as:
•
•
•
•
•
Allowing the flight crew to print messages.
Allowing the auto load of specific uplink messages into the Flight Management System
(FMS). This will reduce crew-input errors.
Allowing the crew to downlink a complex route clearance request, which the controller
can re-send when approved without having to type a long string of coordinates.
Specific uplink messages arm the FMS to automatically downlink a report when an event,
such as crossing a waypoint, occurs. This automation assists with workload management
for the flight crew and the controller.
Specific downlink messages, and the response to some uplink messages will
automatically update the Flight Data Record in some ground systems.
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Global Navigation
Satellite System
Aeronautical Mobile
Satellite System
Airborne equipment (avionics)
VHF Radio
Remote Ground
Station
Data Communications Networks
Satellite Ground
Station
HF Radio Remote
Ground Station
ATC Centres
Source: Study Team
Figure 14.3.1 CPDLC (ADS-C) Concept
To cope with increasing air traffic volume in the future, the Team recommends the introduction
of the CPDLC which is a data link function for Long Term Master Plan (from the year 2016
through the year 2025).
The Team also recommends that current air-ground facilities such as VHF-ER should be
continuously used as back-up functions for communication after the introduction of newly
development data link communication functions.
(2)
Improvement of Surveillance Function
En-route surveillance for 4 FIRs is carried out by 11 MSSRs in 3 countries. These radars
(MSSRs) cover almost all high altitude airspace. However, there are some blind areas at lower
altitude and in oceanic area in HCM FIR.
One of the solutions for shortage of radar coverage is to share radar data with 3 countries. But,
it may be difficult to eliminate all blind areas completely due to geophysical reason, even if the
radar data sharing will be accomplished. As alternatives to solve this issue, it is thought suitable
to introduce ADS (Automatic Dependent Surveillance) technology which is recommended by
ICAO.
Automatic Dependent Surveillance - Broadcast (ADS-B) is a critical component of new
CNS/ATM systems, since ADS-B offers significant safety, cost and operational benefits over
traditional radar system. Aircraft equipped with ADS-B automatically and constantly transmit
position information derived from a Global Navigation Satellite System (GNSS), along with
other information such as altitude, heading, velocity and identification data. This information
can be received and decoded, by other aircraft and by ADS-B ground station, can also be made
available to air traffic management systems.
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Source: Study Team
Figure 14.3.2 ADS-B Concept
While, ADS-C is a method of surveillance that relies on (is dependent on) downlink reports
from an aircraft's avionics that occur automatically in accordance with contracts established
between the ATC ground system and the aircraft's avionics. Reports can be sent whenever
specific events occur, or specific time intervals are reached. ADS-C provides accurate
surveillance reports in remote and oceanic areas. The reports are converted by more advanced
data link equipped ground stations into a track and presented on the controller's air situation
display to provide enhanced situational awareness and the potential for reduced separation
standards.
The Team recommends the introduction of the ADS-B and ADS-C to cope with the issue of
blind area and strengthen surveillance function in oceanic area. The Team also recommends
that current MSSR should be continuously used as main or back-up surveillance facility after
the introduction of ADS-B and ADS-C.
Both MSSR and ADS are utilized with the aim of securing high reliable and redundant
surveillance function; for example Japan and other advanced countries.
(3)
Upgrading Data Exchange Function between 3 countries
Ground to ground systems connect among international airports, air traffic control facilities and
international airline companies, and ensure the telecommunication necessary for safety,
regularity and efficiency of international flight. These systems exchange vital information for
aircraft operations such as flight safety, meteorological, flight regularity and aeronautical
administrative messages. AFTN evolved to provide this ground to ground infrastructure by
using protocols that are originally derived from Telex. AFTN is both a dedicated
telecommunications infrastructure and a special purpose messaging protocol for providing
ground to ground communications.
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Meanwhile, there is an issue triggered off AFTN’s small transmissible capacity and exclusive
protocol, which causes the limitation of transmission ability of information.
In case of the line trouble of domestic AFTN line in Lao PDR, aeronautical information is sent
by voice communication using a public phone or a cellular phone. To solve the issue such an
unreliable voice communication, it would be a good measure to introduce the AMHS (ATS
Message Handling System) into three (3) countries concerned.
AMHS is defined in a set of ICAO standard and recommended practices that are being adopted
to replace the existing AFTN system for ground to ground communications. AMHS is based on
the International Telecommunications Union (ITU) X.400 messaging standards, which provides
the core messaging framework that AMHS extends to support aeronautical applications.
AMHS offers a number of benefits over the AFTN system, including:
1) AMHS can operate over a general purpose network, which can be shared with other
systems, rather than the dedicated AFTN network.
2) AMHS define the basic ATS Message Service, which gives an application service
equivalent to the existing AFTN. This enables a straight forward co-existence and
transition strategy.
3) AMHS defines the Extended ATS Message Service, which enables the following new
capabilities:
• The general body part capabilities of X.400 can be used to enable transfer of additional,
new and extended information over the X.400 messaging infrastructure, as well as
existing ATC messages.
• Support of large messages and fast communication speed by ATN environments.
• Digital signature of messages, to provide content integrity, origin authentication and
non-repudiation.
• A directory is provided, which enables address verification at message submission time,
managing security parameters and determining recipient capabilities.
AFTN Conversion to AMHS Vietnam plans for BIS Routers in 2010-2012; AFTN/AMHS Trial
is scheduled for 2010, with full operation by 2012. Study Team recommends to Cambodia and
Lao PDR to be harmonized with this schedule.
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Source: Study Team
Figure 14.3.3 Existing AFTN Concept
Source: Study Team
Figure 14.3.4 ATN Concept
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Source: Study Team
Figure 14.3.5 ATN based AMHS Concept
(4)
Improvement of ATC in each country
1)
Renewal of Letter of Agreement regarding Transfer of Control
a. Present situation
There is need for the renewal of Letter of Agreement (LoA) between/among neighboring
ACCs. This is essential improvements to be needed because almost all of LoA are signed
ten (10) minuets longitudinal separation for the transfer of control. To reduce not only the
longitudinal separation but also implementation of transfer of radar control, the renewal
should be recommended.
b. Phased development plan
• Arrangement of meeting with neighboring ACC concerned: Meeting will be held by
early 2010
• Trial for transfer of control: 2010~2011
• Implementation of reduced separation: 2011
2)
Transfer of Control (Introduction of AIDC)
a. Present situation
Transfer of control is strongly required for the reduction of separation of aircraft. It needs
due consideration in terms of radar coverage (or none radar coverage), hand-off points,
communication which is including controller to controller, etc. The following Road Map
covers automatic transfer of control which will be realized by AIDC.
b. Introduction of AIDC
The AIDC application supports information exchanges between ATC application
processes within automated ATS systems located at different ATSUs. This application
supports the Notification, Coordination, and the Transfer of Communications and Control
functions between these ATSUs.
Asia/Pacific Air Navigation Planning and Implementation Regional Group (APANPIRG),
at its fourth meeting (Canberra, March 1994), undertook the task of developing the
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inter-facility message exchanges needed to support automation in the regions. The ICAO
ADS Panel then adopted the AIDC message set and included it as guidance material. At
the thirteenth meeting of APANPIRG (Bangkok, September 2002) decision 13/9 was
made to reconvene the AIDC Task Force to undertake the reviewing and updating of the
Asia/Pacific AIDC Interface Control Document (ICD). The AIDC Review Task Force
met in Brisbane on the 27th and 28th of March 2003. As a result of this meeting the
Asia/Pacific AIDC ICD was updated to include:
• Additional clarification of certain message types
• Improved consistency of the terminology used in the document
• Incorporation of recent changes to PANS-ATM Doc 4444 and Doc 9694, regarding
additional optional sub-fields in ICAO field 14
• Proposed additional message types, Application Status Monitor (ASM), FANS
Application Notification (FAN) and FANS Completion Notification (FCN).
AFTN-based AIDC is scheduled for 2012 in Vietnam. Cambodia and Lao should
accelerate their implementation timelines for AIDC.
Source: Study Team
Figure 14.3.6 AIDC Flow
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The Asia/Pacific (A/P) AIDC Message set supports six ATS-related functions:
1. Notification;
2. Co-ordination;
3. Transfer of Control;
4. General (Text) Information Interchange;
5. Surveillance Data Transfer; and
6. Application Management.
c. Phased development plan for Cambodia and Lao PDR
• Arrangement of Meeting to discuss the possibility of transfer of control: 2009~2011
• System design: 2011~2012
• Preparation of equipment procurement: 2012~2014
• Installment of equipment and test: 2014
• Implementation of transfer of control: 2015
d. Phased development plan for Vietnam
• Arrangement of Meeting to discuss the possibility of transfer of control: 2009~
• System design: 2010~
• Preparation of equipment procurement: 2011~
• Installment of equipment and test: 2011
• Implementation of transfer of control: 2012~
3)
Introduction of Air Traffic Incidents Reporting System and Follow-up System for
Cambodia and Lao PDR
a. Present situation
Fortunately in both Cambodia and Lao PDR have no report regarding air traffic incident
which is so-called “Near Miss Report”. It may be considered the number of air traffic at
airports and respective ACC is not so many. However it is better to prepare the air traffic
incidents reporting system and inter alia follow-up system that is more effective so as to
prevent the recurrence of an incident.
b. Phased development plan
• Study of the systems: 2009
• Introduction of the systems: 2010
(5)
Introduction of ASM and ATFM in each country
1)
Present situation
It is very important to introduce the concepts of Airspace Management (ASM) and Air Traffic
Flow Management (ATFM) to the Study in 3 countries because ATM comprises the functions
of air traffic services (ATS), AMS and ATFM.
The ATS in 3 countries is carried out well in accordance with the Standards and Recommended
Practices (SARPs) of ICAO. However, each country has no concepts of the implementation
of ASM and ATFM at present.
There are two approaches or stepwise implementations to carry out appropriate ATFM and
ASM. One is only to assign personnel in charge of airspace liaison officers for ASM or flow
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control supervisors for ATFM and keep working position for them, the other one is to establish
extra organizations and introduce computerized ATFM and ASM functions. Judging from
present air traffic volume and future forecasting demand even in Long Term, the Team
recognizes that Cambodia and Lao PDR need not establish extra organization and introduce
computerized system for ATFM and ASM. Thus, the Team recommends making up two goals
for both these 2 countries and Vietnam.
2)
Phased development plan for Cambodia and Lao PDR
The ASM and ATFM are implemented usually by ATS as a daily work. Therefore these systems
are coordination services and do not need to establish extra organizations. It means to assign
personnel in charge of airspace liaison officers for ASM or flow control supervisors for ATFM.
• Assignment and training: 2009~2014
• Implementation: 2015
3)
Development plan for Vietnam
For introducing Air Space Management and Air Traffic Flow Management in Long Term, the
following work required to support these ASM/ATFM activities for transition should be
considered:
• Mission Analysis - Consists of defining the mission and purpose for ASM/ATFM.
• Concept Exploration - Certain mission needs should be allocated to capabilities and an
initial concept of operations will be created.
• Concept Development – will strive to refine the operational concept, initiates requirements,
develops functional specifications, defines performance criteria and evaluates alternatives.
• Prototype Development – an operational prototype will be developed as a research (or beta
version) of an operational system.
• System Modeling and Simulation – this will allow for assessment of multiple, interacting
Air Flow Traffic Management initiatives to be performed in a what-if mode prior to actual
implementation.
• Research Infrastructure – this will provide a comprehensive set of tools and data archives
to support analysis, human-in-the-loop simulations and refinement of operational
concepts.
All work efforts, including Program Management and System Engineering should be defined in
individual Task Orders. This will prevent data overload and the fear-factor that stakeholders
and Regulators will feel at looking towards commencement of such a huge project by breaking
everything up into manageable pieces.
(6)
Improvement of interface between FDP and RDP in each ACC (Phnom Penh
ACC/Vientiane ACC)
1)
Present situation
Interface between FDP (Flight plan Data Processing) and RDP (Radar Data Processing) is not
perfect for assignment and provision of the discrete assigned SSR Code. The procedure of the
assignment of discrete assigned SSR Code for departure aircraft is manual input in ATC
computers and not from an AFTN (Aeronautical Fixed Telecommunication Network). The
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procedure of the provision of the discrete assigned SSR Code for departure aircraft at airport is
as follows.
Upon receiving initial call from a pilot requested ATC clearance to ATC unit, an air traffic
controller of ACC or APP assign discrete assigned SSR Code in regular order and input it
manually into ATC computers.
The discrete assigned SSR Code is provided the pilot when ATC unit issues ATC clearance.
The procedure needs additional one position for assignment and provision of the discrete
assigned SSR Code. In order to reduce workload of air traffic controller, a filed flight plan or
repetitive flight plan should be stored in ATC computers.
2)
14.4
Phased development plan
• System design, equipment procurement and installation: 2009~2014
• Implementation: 2015
Automation of Air Traffic Control (ATC)
ATM system is the aggregation of airborne functions and ground-based functions in order to
ensure the safe and efficient movement of aircraft during all phase of operation. ATM is used to
describe airspace and ATM implementation that are carried out jointly by aeronautical
authorities concerned with the planning and administration for the effective use of airspace and
flow of traffic within their responsible airspace. The general objective of the ATM is to allow
aircraft operators to keep the scheduled departure and arrival and to take preferred flight
profiles with a minimum of limitations and without jeopardizing agreed level of safety. As
mentioned above, the ATM is made up of an air and a ground component, which is closely
integrated through well-defined procedures and interfaces. The ground component consists of
Air Traffic Services (ATS), Air Traffic Flow Management (ATFM) and Airspace Management
ASM).
There is an issue of interfaces between FDP and RDP in Cambodia and Lao PDR in terms of
automatic assignment of SSR for departure aircraft. In addition to the issue, the Team examines
many issues such as additional functions for the integration of radar data of three (3) countries
concerned, the needs of system upgrade including the functional availability of
ADS-B,CPDLC/ADS-C, etc.
The Team recommends the following functions should be equipped on the occasion of the
renewal of each ATM system in each three (3) countries.
(1)
FDP Function
As a general rule, FDP system processes information such as route of flight from departure to
arrival (from gate to gate), altitude, estimated elapse time, amount of fuel, etc. including in
flight plan, distribute the flight plan to the ATC facilities, electronic flight strip including print
out flight progress strips and distribute it to air traffic controllers.
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To reduce the workload of air traffic controllers, the Team recommends that the allocation and
assignment of discrete SSR Code to each aircraft before departure should be processed
automatically through ATC computer system at the time of renewal.
(2)
RDP Function
RDP system is a radar alpha numeric system which tracks and displays a radar position of the
aircraft in conjunction with its identification, altitude, airspeed and other ATC information
based on the flight plan processed by the FDP system mentioned above.
RDP function consists of Multi-Radar Tracking, Safety Alert, Recording and Playback, etc. It
receives radar data from PSR/MSSR and processes the radar data in order to display these data
on radar scopes for air traffic controller(s).
In case of the outage of MSSR radar or scheduled maintenance work, the radar coverage should
be made blind area up by other MSSR radar(s) with its own country or other country’s one. The
Team recommends that three (3) countries should plan to add needful function to be prepared
in collaboration with 3 countries.
(3)
Radar By-pass Processing Function
In the event of failure of RDP system in Area Control Center (ACC), radar by-pass function is
able to process single radar data and to display the data in radar scope by its by-pass function.
At the time of shut down of the radar by-pass function in ACC, the radar by-pass function of
Airport’s radar will be able to provide the single radar data to ACC’s radar, it can continue
radar monitoring. Therefore, this function is a fail-safe system. This function to be used for
new ATM system should be reliable and redundant.
(4)
ADS-B Processing Function
For the purpose of the improvement of surveillance function for aircraft flying oceanic area
and/or blind area, and in terms of redundancy of SSR, new CNS/ATM systems is planning the
introduction of ADS-B. As for ADS-B, new ATM system needs the following ADS-B’s
functions such as Connection, Track, Alert and Track/Flight Plan Integrate Management. On
the occasion of the introduction of the ADS-B, it is important to improve these functions which
are processed by the new ATM system.
(5)
CPDLC Processing Function
For the purpose of the establishment of continuous communications with aircraft flying oceanic
area and/or blind area, and the reduction of air traffic controllers’ workload, and the
improvement of accuracy of information delivery between a controller and a pilot, the Team
recommends to introduce CPDLC during long term, e.g. from the year 2016 through the year
2025.
As for CPDLC, new ATM system needs the following CPDLC’s functions such as Connection
and Message Management.
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On the occasion of the introduction of the CPDLC during long term, it is important to improve
this function which is processed by the new ATM system.
(6)
Pre Departure Clearance (PDC) Processing Function
This PDC processing function is a function for the issuance of ATC clearance to departure
aircraft by using data communication. It is effective for the reduction of air traffic controllers’
workload, and the improvement of accuracy of information delivery between a controller and a
pilot.
The Team recommends the introduction of PDC processing function, i.e. Connection and
Message Management, for the new ATM system.
(7)
Advanced Safety Alert Processing Function
Under the increasing air transport demand, and the introduction of PBN (Performance Based
Navigation) operations which decrease separations between aircraft, it is essential to introduce
Safety Alert Function into ATM automation system in order to implement effective air traffic
control service.
The Team recommends that the ATM automation system should be added the following Safety
Alert Functions.
• Conflict Alert (e.g. Short Term, Medium Term Conflict Alert)
• Danger Area Infringement Warning (DAIW) Alert
• Minimum Safe Altitude Warning (MSAW) Alert
• Route Adherence Monitoring (RAM) Alert
• Cleared Level Adherence Monitoring (CLAM) Alert
• Restricted Area Warning Alert
• ADS Route Conformance Warning (ARCW) Alert
• Missing Position Report Alert
• Flight Plan Conflict Probe
The time of introduction of each function listed above would be better to adjust the time of
renewal of ATM system from the point of view of cost-benefit.
14.5
Central Information Management and Quality Monitoring
System Wide Information Management (SWIM) is one of the central information management
concepts and to provide an open and flexible information management architecture that
facilitates sharing of operational data throughout the national airspace system (and theoretically
internationally as well).
SWIM is an advanced technology program designed to facilitate greater sharing of Air Traffic
Management (ATM) system information, such as airport operational status, weather
information, flight data, status of special use airspace, and National Airspace System (NAS)
restrictions. SWIM will support current and future NAS programs by providing flexible and
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secure information management architecture for sharing NAS information. SWIM will use
commercial off-the-shelf hardware and software to support a Service Oriented Architecture
(SOA) that will facilitate the addition of new systems and data exchanges and increase
common situational awareness.
Eurocontrol initially presented the SWIM System concept to the FAA in 1997, where it has
been under development ever since. In 2005, the International Civil Aviation Organization
(ICAO) Global Air Traffic Management (ATM) Operational Concept adopted the SWIM
concept to promote information-based ATM integration. SWIM is now part of development
projects in both the United States (NextGen) and the European Union (Single European Sky
ATM Research - SESAR).
SWIM is part of The Next Generation Air Transportation System, or NextGen, an umbrella
term for the ongoing evolution of the United States National Airspace System (NAS) from a
ground-based system of air traffic control (ATC) to a satellite-based system of air traffic
management. The transformation to NextGen requires programs and technologies that provide
more efficient operations, including streamlined communications capabilities. The SWIM
program is an integral part of that transformation that will connect FAA systems. The SWIM
program will also enable interaction with other members of the decision-making community
including other government agencies, air navigation service providers, and airspace users.
SWIM is essential to providing the most efficient use of airspace, managing air traffic around
weather, and increasing common situational awareness on the ground. SWIM core services will
enable systems to request and receive information when they need it, subscribe for automatic
receipt, and publish information and services as appropriate. This will provide for sharing of
information across different systems. This will allow airspace users and controllers to access
the most current information that may be affecting their area of responsibility in a more
efficient manner. SWIM will improve decision-making and streamline information sharing for
improved planning and execution.
SWIM will also help reduce infrastructure costs by decreasing the number of unique interfaces
between systems. Initially, SWIM will provide a common interface framework, reducing the
operation and maintenance costs of current interfaces. New systems will interface with each
other via SWIM-compliant interfaces, thereby reducing future data interface development
costs. Ultimately, redundant data sources will no longer be needed, and associated systems will
be decommissioned.
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Source: Study Team
Figure 14.5.1
Items of SWIM
In case of Japan
There is good example of central information management conducted at Aeronautical
Information Service Center (AISC) in Japan. The following is the flow of information of
NOTAM at the AISC.
(1) A person or an organization that wants to issue a NOTAN will submit a draft NOTAM to
the AISC in Narita International Airport through electronic mail, facsimile or exclusive
line.
(2) The official (s) at AISC will edit the draft on displays (Aeronautical Information Service
Operation Desk Terminal), and send it to FDMS (Flight Data Management System)
installed in ATMC (Air Traffic Management Center) in Fukuoka prefecture through FIMST
(Flight Information Management Terminal).
(3) The NOTAM will be sent to airlines, Ministry of Defense, International NOF (NOTAM
Office), etc. from the FDMS.
Judging from the above, the all NOTAM information in Japan is integrated into the AISC. It
means that the integration of information is a central information management. Meanwhile,
ICAO is requesting the provision of higher-quality aeronautical information in accordance with
quality management system based on ISO 9000 series. It is clear that the integration of
information is easy to monitor quality management.
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Raw data prvoider
Aeronautical Information Service Centre
(AISC)
AIS operation desk terminal
FIMS terminal
Flight Data
Management System
(FDMS)
Airline
CNS/ATM (AIS) DB Terminal
CNS/ATM DB
Communication Navigation
Surveillance / Air Traffic
Management Data Base
Internet
Air Traffic Management Centre
(ATMC)
TDU, EDU
Terminal, En-route Data
Display Unit
Ministry of Defense
Flight Service Information Handling
System (FIHS)
(Tokyo, Kansai International Office)
Airport Office and Branch
International NOTAM
Office (NOF)
Legend
NOTAM Raw Data
NOTAM
Graphic NOTAM
Airport Administrator
Source: JCAB catalogue
Figure 14.5.2 AIS Automated System in Japan
14.6
Air Traffic Flow Management (ATFM)
14.6.1 General
The ATFM is an important element of ATM. The ATFM is carried out by a daily work of ATS,
inter alia air traffic controllers works. For instance, when an air traffic control unit that will
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control a flight reaches capacity, arriving aircraft are directed towards holding pattern where
they circle until it is their turn to land. Because aircraft flying in circles is an inefficient and
costly way of delaying aircraft, it is preferable to keep them on the ground at their place of
departure, called a ground delay program. This way, the delay can be waited out on the ground
with engines-off, saving considerable amounts of fuel. Obviously, careful calculation of en
route time for each flight and traffic flow as a whole is needed, which is highly dependent on
processing equipment.
The flow management function is to balance traffic demand and ATC capacity, and the task of
ATFM focused on a general picture of traffic and on the planning strategy required to ensure
efficient use of airports and airspaces in specific area. The flow management should be
automated systems and has common databases such as flight plan requested by airline to
provide a consistent flow management service.
Source: Study Team
Figure 14.6.1 Sample of ATFM Concept
14.6.2 Implementation of ATFM
Lao PDR had total 118,400 traffic volumes of overflights and flights to/from airports in 2008.
And Cambodia had total 65,100 traffic volumes in 2008.
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Judging from present air traffic volume condition in Cambodia, Lao PDR, and Vietnam, the
Team recognizes that Cambodia and Lao PDR need not establish extra organizations at the
present. However, it is important to study the concept of ATFM for coping with increasing air
traffic volume in the future.
Also in case of growing enough air traffic demand and being required ATFM center for
Cambodia and Lao PDR in future, utilizing ATFM centre in Hanoi as unified 3 countries’
ATFM centre will be one of better ways for collaborative operation.
Note: Thailand (Aerothai) is now attempting to convince ICAO to let them grow their ACC
into an ATFM Center (by 2013), so that close coordination should be made among the
countries for introducing ATFM function in accordance with ICAO APNPARG regional
development plan.
(1)
Cambodia and Lao PDR
As mentioned before, the ATFM is an important element of ATM. The ATFM is carried out by
a daily work of ATS, inter alia air traffic controllers works. For instance, if an aircraft accident
is occurred and closed at the airport, the air traffic controllers working in ACC having
jurisdiction of the airport take their emergency measures such as setting up a diversion of
aircraft in air, scattering of aircraft flow to reduce the congestion of air traffic, etc. The
measures are required skilled coordination techniques. The Team considers that it is better to
establish an extra organization such as an ATFM Center in order to control heavy air traffic
volume. Judging from present air traffic volume condition in Cambodia and Lao PDR, the
Team recognizes that both countries need not establish extra organizations at the present.
However, it is important to study the concept of ATFM for coping with increasing air traffic
volume in the future.
The Team recommends that ACC in each country should educate and train personnel in charge
of the ATFM, e.g. traffic flow control supervisors.
In the future, e.g. the period of long term or later, the introduction of the integrated flow
management function in Cambodia and Lao PDR should be studied in light of air traffic
demand.
(2)
Vietnam
VANSCORP is now planning to create a new Area Control Center (ACC) at Hanoi. To cope
with the future traffic volume, VANSCORP should consider introducing more functionality to
handle full Air Traffic Flow Management (ATFM) at new Hanoi ACC in the future.
The Team has a vision for modernizing the airspace systems in Vietnam to meet future air
traffic demands. The transformation will require concept engineering, development and
deployment of new Air Traffic Flow Management systems, technologies, and decision support
tools to meet the growing aviation demands safely and efficiently. It will be necessary to
work in cooperation with Civil Aviation Administration of Vietnam (CAAV); ATS Service
Providers; and other national airspace users to implement ATFM programs. At this moment,
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there is not large amount of ATS delays in Vietnam, however, future Demand Forecasting for
Vietnam shows that this will be a growing problem in future. It will be necessary to reduce
such delays to ensure smooth and efficient traffic flow through controlled airspace, thereby
saving the flying public and airlines millions of dollars per year in avoided delay. The
organizations in Vietnam that is responsible for Air Traffic Operations, will be responsible for
developing and deploying technology to support the safe and efficient movement of aircraft
through their airspace systems, and ensuring that new ATFM systems and technologies provide
nationwide, as well as localized benefits for particular volumes of airspace or phases of flight
(e.g. Departure; Transition; En-route; Transition; Arrival).
One of the pillars of future ATFM is the concept that ATS Service Providers (ATC Controllers;
Flight Planning/Service Station Personnel; Meteorologists) as well as the airspace users (e.g.
Airline Flight Operations Divisions; and Pilots) all collaborate in the decision making process
(Collaborative Decision Making (CDM)) with regard to Routes of Flight and airspace use. This
will yield great improvements in flexibility and predictability for future Air Traffic Control and
customers. It will require teamwork, shared information, and clearly defined roles and
responsibilities to proactively balance system demand and capacity challenges. It will allow
common situational awareness, distributed planning and performance analysis.
The
objectives will be:
• Better-informed traffic management decisions
• Efficient use of nationwide airspace resources and delay reduction
• Increased flexibility for nationwide airspace users to meet operational and economic
objectives
In other parts of the world (e.g. Japan with JCAB; USA with FAA; Europe with Eurocontrol),
such CDM-developed concepts have already proven their benefit. The Team intends to
provide a basic road map to a safer, more equitable and more efficient air transportation system
through ATFM & CDM.
Vietnam will need to dedicate Engineers and concept engineering activities in several key
ATFM concept areas.
• Data projects - ATFM information in both digital and graphic formats
• Arrival Flow Management projects - improve airport arrival throughput
• Departure Flow Management projects - improve airport departure throughput
• En-route Congestion Management projects – methods and procedures to predict and
reduce En-route congestion
• Electronic Negotiation to support 3-D and 4-D trajectory based operations for planning
and execution
• Performance Monitoring and Assessment projects – to support the continuous learning
of how to make better decisions based upon ATFM monitoring.
• System Wide Modeling and Integration
Each of the above projects has multiple sub-projects. It will be necessary for Steering
Committees and research/technical working groups to collaborate with stakeholders to identify,
prioritize and guide concepts though the four phases of progression:
• Concept Exploration
• Concept Development
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•
•
Prototype Development
Full Scale Development.
Following these 4-phases will allow Vietnam more flexibility in responding to stakeholder
needs, changing priorities, and will lower program risk. Concepts that are determined
operationally suitable by the CAAV, and have successfully transition through all four phases,
may ultimately end up as part of the Air Traffic Flow Management System.
14.7
Air Space Management (ASM)
14.7.1 General
The ASM is an important element of ATM. The ASM may be called as coordination services.
Sometimes airspace users request conflicting requirement so as to gain advantage each other. It
may be often caused by the different purpose of military use or civil use. The main purpose of
ASM is the effective use of airspace. Time sharing, segregation of airspace, etc. may be ASM
solution.
The ACC should have responsibilities for promoting the effective use of airspace, doing such
things as providing “ Conditional Route” that allow civilian aircraft to pass through military
restricted airspace where the military section does not plan to use (day and time) in
coordination with military officers. The flexible use of military airspace is so effective flight
for the aircraft operations such as reduce the flight time and consumption of fuel. The role of
ASM is:
• Schedule and status coordination of military airspace
• Coordination of flexible use of airspace
• Setting Conditional Routes
• Sector combinations using dependent sectors to distribute acceptable workload for the
ATC controller
Source: Study Team
Figure 14.7.1 Sample of ASM Concept
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Moreover, the ASM includes the roles such as designing of airspace as well as development of
flexible operation methods with the aim of reducing ATC controller workload and increasing
available capacity of airspace.
14.7.2 Implementation of ASM
The step for the implementation of ASM will be prepared the position for airspace liaison
officers at control room in each ACC. And next step will be education and training for
personnel who are selected as airspace liaison officers. Those who will be better air traffic
controllers. It will also be better to assign as exclusive job. The ASM needs tough coordination
between ATS provider and airspace users. The personnel in charge of the ASM are required
skilled coordination techniques. Therefore the Team recommends that ACC in each country
should educate and train personnel in charge of the ASM, e.g. airspace liaison officers.
The purpose of ASM processing function is to maximize use of available airspace within a
given airspace structure. Using the airspace, close co-ordination and supervision are essential in
order to meet the contrasting and legitimate requirements of all users and minimize any
restriction on operations.
In the future, e.g. the period of long term or later, the introduction of the airspace management
processing function in Cambodia and Lao PDR should be studied in light of air traffic demand.
As for Vietnam, computerized airspace management automation system should be studied and
considered introducing in Long Term.
14.8
Consideration to the introduction of new air traffic control services
To cope with the increasing number of air traffic movement in three (3) countries in the future,
JICA Study Team considered the introduction of the following new air traffic control services
such as an aerodrome control or an approach control. The consideration of additional services
needs the standard for the introduction of new services. The standard should be prepared by
each country in conjunction with the situations such as resources, the capacity of airport and/or
airspace, etc. However, the JICA Study Team applied a standard which is in general use in
Japan in the light of the application of three-country common standard.
14.8.1 Establishment of terminal radar control (radar approach control) units
(1) There is a considerable issue to be solved by the establishing of new terminal radar control
unit in addition to the present aerodrome control unit in an airport in order to cope with the
future increase of air traffic volume. JICA Study Team made the following consideration.
(2) As for the name of airport which is conducting approach control services and its handling
number of aircraft movement (with Instrument Flight Rule: IFR) in 2008, the Chapter 5 in
this report shows as follows.
Phnom Penh
Siem Reap
Vientiane
Noi bai
Tan Son Nhat
Da Nang
25,200 times
24,200 times
12,200 times
50,100 times
86,500 times
13,300 times
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Note. – “times”: Total flight numbers which were added all arrival and departure aircraft.
According to the Japanese “Standard for the establishment of air navigational aids, facilities,
etc. ” (hereinafter referred to as “Japanese Standard”), terminal radar control (radar approach
control) units will be established by the following standards. An aerodrome control unit which
has 10 or 14.5 hours operation in a day and more than 31,000 times in a year in air traffic
movement will be approved to establish a terminal radar control unit in addition to the existing
aerodrome control unit. In the airport of 24 hours operation, the standard will be needed more
than 53,000 times in a year.
If 3 countries apply the Japanese standards mentioned above, Tan Son Nhat international
airport which has 86,500 times air traffic movement may be eligible to establish terminal radar
control unit.
However, there are several international airports providing terminal radar control which are
under the Japanese standard. JICA Study Team supposes the reason that they must use radar for
special circumstances such as Noi bai airport is close to military training airspace.
14.8.2 Introduction of non-radar approach control services
(1) The Japanese Standard prescribes that a non-radar approach control unit may be established
as an alternative unit with an aerodrome control unit on condition that terminal radar
control unit until starting its service. In the non-radar approach control unit, the standard of
air traffic movement will be needed more than 18,000 times in IFR in a year.
It seems difficult to apply the Japanese Standard to the additional establishment of
non-radar approach control units in 3 countries. The JICA Study Team considered that it
will be invaluable to study the possibility of the establishment in the light of the application
of three-country common standard in 3 countries. JICA Study Team made the following
consideration.
(2) Demand forecast in Cambodia shows that the total numbers of air traffic movement in year
2015 will be 3,100 times for six (6) airports, i.e. five (5) local airports and a Sihanoukville
international airport. In year 2025, it shows 9,100 times for the same 6 airports. Therefore,
each airport does not need a non-radar approach control unit because of less than 18,000
times of Japanese Standard.
In Lao PDR, the demand forecast in Luang Phabang airport shows that the total numbers of air
traffic movement in year 2015 will be 12,700 times, and 20,900 times in year 2025. In Pakse
airport, it shows 3,800 times in year 2015, and 10,600 times in year 2025. In Savannakhet
airport, 1,100 times in year 2015, and 2,600 times in year 2025. And other seven (7) airports’
total air traffic movement will be 5,500 times in year 2015, and 7,900 times in year 2025.
Judging from the demand forecast, Luang Phabang international airport will be eligible to
establish non-radar approach control unit by year 2025.
In Vietnam, the demand forecast shows that the total numbers of air traffic movement in year
2015 will be 57,700 times for seventeen (17) airports, i.e. sixteen (16) local airports and a Phu
Bai international airport. In year 2025, it shows 112,400 times for the same 17 airports. Among
these 17 airports, there are not prevailing airports as compare with the numbers of air traffic
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movement. It can say that each airport is not able to reach the Japanese Standard, e.g. more
than 18,000 times in IFR in a year, by year 2025. Therefore, JICA Study Team considers that
the 17 airport in Vietnam need not to establish new non-radar approach control unit. However,
JICA Study Team understands that Phu Bai international airport will possible become main
international airport in future. At that time, the non-radar approach control or terminal radar
control unit in Phu Bai international airport will be desired to be established. The Phu Bai
international airport is located at 32 nautical miles North West of Da Nang airport which
providing radar services for its airport. JICA Study Team considers that there is the possibility
of integration of radar approach services in both Phu Bai and Da Nang airports.
14.8.3 Introduction of aerodrome control services
(1) There are local airports in Cambodia and Lao PDR, in which do not provide air traffic
controllers. These situations exist not only in Cambodia and Lao PDR but also in Japan. In
Japan, a radio man who issue operational information such as weather, an active runway,
etc. to pilot(s) in stead of air traffic controllers at slow traffic airport. The radio man is
called as a flight safety official in Japan. The responsibilities of a flight safety official are
limited as compared to the one of a air traffic controller. In general, a flight safety official
can issue only information regarding flight safety, but cannot issue instructions to pilots. It
is fact that airports which were allocated by more air traffic controllers than flight safety
officials are trending upward in Japan. JICA Study Team cannot say which one, e.g. no
provision of air traffic controllers or provision of radio men or personnel of these sorts, but
can say that the following Japanese Standard is used to establish an aerodrome control unit
in Japan. This Standard is one of examples.
(2) Japan Civil Aviation Bureau (JCAB) applies the following Japanese Standard in order to
establish an aerodrome control unit. The following table shows three (3) kinds of airports
which have different operation hours respectively. And each airport has two (2) standards,
i.e. one for annual air traffic volume and another for IFR annual air traffic volume. And
respective 2 standards should be met at any time.
Operation hours
8
10 ~ 14.5
24
Annual traffic volume
More than 15,000 times
More than 18,000 times
More than 30,000 times
IFR annual traffic volume
More than 6,500 times
More than 8,500 times
More than 13,000 times
As mentioned in 15.8.1 (2) above, demand forecast in Cambodia shows that the total numbers
of air traffic movement in year 2015 will be 3,100 times for six (6) airports, i.e. five (5) local
airports and a Sihanoukville international airport. In year 2025, it shows 9,100 times for the
same 6 airports. On average, one local airport in Cambodia will have 510 times in year 2015,
and 1,500 times in year 2025. Meanwhile seven (7) local airports’ total air traffic movement in
Lao PDR will be 5,500 times in year 2015, and 7,900 times in year 2025. On average, one local
airport in Lao PDR will have 790 times in year 2015, and 1,130 times in year 2025.
Therefore one local airport in Cambodia and Lao PDR shows lower flight times than the
minimum air traffic volume of Japanese Standard, i.e. 6,500 times. Therefore, JICA Study
Team considers that there is no airport which needs to be established new aerodrome control
units. However, the conclusion is drawn from Japanese Standard. It is important to prepare
national standard regarding air traffic control (ATC) units with due consideration.
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14.8.4 Consideration to the integration of an area control center (ACC) and approach
control unit(s)
(1) There are several approach control units which have already been integrated into ACC(s) in
each of 3 countries. These are Phnom Penh ACC/APP and Siem Reap APP, Vientiane
ACC/APP, and Ho Chi Minh ACC/APP. (“APP” means an approach control unit.) And
New Hanoi ATC Center is planning to integrate Noi Bai APP. JICA Study Team made the
following consideration.
(2) The merits of the integration of an ACC and approach control units (APP) are able to
manage intensively equipment and personnel such as maintenance staffs and air traffic
controllers. It is also able to reduce expenses caused by the reduction of equipment and
personnel. The centralization of air traffic control (ATC) services leads to wide-area ATC
services. On the contrary there are some demerits on the centralization. From a fail-safe
protection point of view, the dissolution of services is desired in fundamental facilities.
(3) Here JICA Study Team explains the Japanese situations as of the integration. Many local
airports in Japan equip SSRs such as APDU (Aircraft Position Display Unit) and APID
(Aircraft Position Information Display). ACCs control aircraft by using these APDU or
APID. However ACCs control aircraft with non-radar approach control procedures to the
airports which do not equip APDU or APID.
Meanwhile, there are wide-area ATC services in international airports, not in ACCs, such
as Kansai, Chubu and Tokyo international airports. These airports have several satellite
airports, for example, Kansai international airport has Osaka and Kobe airports. Tokyo
international airport will start its operation soon for terminal radar control services in
Narita international airport.
(4) In Cambodia, it is planning to install SSR in a Sihanoukville international airport. After the
completion of the installation of SSR, the terminal radar control services will be
implemented in Phnom Penh ACC. In the near future, approach control services in main
airports, e.g. Phnom Penh, Siem Reap and Sihanoukville, are integrated in a Phnom Penh
ACC.
In Lao PDR, Luang Phabang international airport will be eligible to establish non-radar
approach control unit by year 2025 because of demand forecast conducted by JICA Study
Team. JICA Study Team would like to recommend that the DCA of Lao PDR should give
its careful consideration on merit or demerit as to the approach control services will be
implemented in Vientiane ACC or in Luang Phabang international airport.
In Vietnam, present Da Nang and Noi bai airports conduct their terminal radar control services
respectively. The fact that the two (2) airports carry out approach control seems to be the
complication of military training/airspace and independency of organizations in the Vietnam.
Considering that these circumstances in the Vietnam, it is not realistic to recommend
unconditionally the integration of approach control units into both Hanoi ACC and Ho Chi
Minh ACC.
As mentioned in 15.8.1 (2) above, the demand forecast of air traffic movement shows that
Vietnam’s local airports need not to establish new non-radar approach control unit. It will be
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enough that approach control procedures, i.e. transfer of control between ACC and local airport,
will be continued as usual.
14.9
Automation of Aeronautical Information Services (AIS)
14.9.1 Establishment of Net Working
It is important to automate procedures for Aeronautical Information Services (AIS) same as
aforementioned air traffic control services (ATCS). It also needs the establishment of net
working for the collection and distribution of electronic aeronautical data with higher quality.
ICAO requires each member state to provide high-quality and accurate aeronautical
information and data for ICAO contracting states, and U.S. and European countries have
already took necessary measures to meet to the ICAO requirements. Under the circumstances,
the computerization and the upgrade of the aeronautical information are requested in
accordance with the high performance of aircraft, and high-quality aeronautical information
and accurate management will become more and more important.
ICAO is also requesting the establishment of international NOTAM office (NOF) for the
exchange of aeronautical information. Therefore it is pivotal to establish the international net
working with higher quality in order to meet to the ICAO requirements.
14.9.2 Publication of Aeronautical Information
ICAO defines that each contracting state shall be responsible for aeronautical information
publication, etc. which is one of services of AIS. The following are main publications on
aeronautical information.
(1)
1)
2)
3)
4)
(2)
AIP (Aeronautical Information Publication)
AIP is a publication for aeronautical information of lasting character essential to air
navigation. Electronic publication of the AIP is considered to be a future requirement.
AIP amendment (AIP AMDT) is published for permanent changes to information contained
in AIP.
AIP supplement (AIP SUP) is published for temporary changes.
AIC (Aeronautical Information Circular) is a notice containing information that does not
qualify for the original of NOTAM or for inclusion in AIP.
NOTAM (Notice to Airmen)
NOTAMs are issued in case of containing information concerning the establishment and
change in any aeronautical facility, service, etc., the timely knowledge of which is essential to
personnel concerned with flight operations.
PIB (Pre-flight Information Bulletin)
PIB is a publication prepared for personnel engaged in pre-flight, which is summarized
NOTAMs, AIP supplement and AIC.
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14.9.3 International Exchange of Aeronautical Information
Aeronautical Information Service Center (AISC) was established under the Operations and
Flight Inspection Division, Air Traffic Service Department of JCAB on 1 April 2007, and
started its services at Narita International Airport on 1 July 2007 as an exclusive AIS unit. It
acts as Japanese NOF which was designated for the exchange of NOTAM internationally to
provide timely, high-quality and accurate aeronautical information and data in order to meet the
needs and requirements of all users in the world.
As of 1 January 2009, the AIP are exchanged with sixty three (63) countries and NOTAMs are
also exchanged with eighty one (81) countries on the aeronautical fixed telecommunication
network (AFTN).
In Vietnam, new AIS automation system conforming ICAO requirements will be in operational
condition from the year of 2010.
The Team recommends that Cambodia and Lao PDR will accelerate to introduce this function
to possibly implement international mutual correspondence.
14.9.4 Conceivable Automation of AIS
There are many Aeronautical Information Services (AIS) other than the edition and publication
of AIP, etc. These are, for example, services to accept flight plan, confirm the content of
NOTAM, check airport surface condition, assign spot arrangement, organize search and rescue,
etc.
As mentioned above, some procedures for publication of AIP, NOTAMs, AIC, etc. have been
automated on network established. The Team considers the following services will be
automated in the future in the event of establishment of stable network.
(1) Acceptance of Flight Plan (Flight Plan Entry, Validation and Distribution and Retrieval
Management)
Generally, an airline handling scheduled flights files a flight plan via an exclusive circuit.
However a non-scheduled aircraft operator may use Web browser system (Internet) for a flight
plan filing. The others will directly submit a handwritten or typewritten flight plan to a flight
operation office at airport, or send the flight plan by a facsimile or voice communication by
telephone.
The best way to reduce one’s workload is to file a flight plan via an exclusive circuit as
mentioned above. It would be benefited by the establishment of stable network.
(2) MET Data Entry, Validation and Distribution and Retrieval Management
It is pivotal that the meteorological information should be timely distributed to airline operator,
service provider, aerodrome operator, etc. in order to assure the safety of aircraft operation.
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In case of the introduction of AIS automation system related to meteorological information, the
Team recommends that management functions such as entry, validation, distribution and
retrieval should be installed in the system.
(3) NOTAM Issuance and Data Management
To provide or exchange NOTAM in timely, high-quality and accurate manner, NOTAM
issuance and data management will be automated to meet the needs and requirements of all
users in the world such as international NOTAM office (NOF) in other countries, airport
administrators, military organizations, airlines, etc.
(4) e-AIP Generation and Management
Aeronautical Information Publication (AIP) is a publication containing aeronautical
information. The printed AIP is prevalent among the world. ICAO requires Contracting States
to provide high-quality and accurate aeronautical information which is processed by electronic
data, a so-called e-AIP, and to exchange internationally the printed AIP and/or e-AIP.
The computerization of aeronautical information would lead the early introduction of the
e-AIP.
(5) Basic/Static Data Management
Under the recommendation of ICAO, basic and static data related to FIR, aerodromes,
NAVAIDs, areas, maps, rules and aeronautical information such as NOTAM will be managed
by AIS automation system. AICM (Aeronautical Information Conceptual Model) /AIXM
(Aeronautical Information eXchange Model) which are adapted as model of database and data
exchange in EUROCONTROL and FAA are proposed to be introduced into AIS automation
system
(6) Mapping, Chart Generation and Management
Present and future navigation systems and other traffic management systems are being more
data dependent. In this data-oriented environment, ICAO amended ANNEX15 (Aeronautical
Information Services) including electronic terrain and obstacle data (e-TOD), which is based
GIS (Geographical Information System), are made available for use by international civil
aviation.
As for the establishment of GIS data, it is needed to convert into World Geodetic System-1984
(WGS-84) geographical data. However there are some issues such as surveying is not
conducted. Therefore it is better to convert into the WGS-84 as soon as possible. And it would
be better to preparer the functions of mapping, chart generation and management including
e-TDO one by one.
It will be useful for the user to provide graphic information such as closed runway/taxiway,
NOTAM, etc. which is shown as examples in Japan.
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(7) Web Function for Search and Rescue, MET and NOTAM
It will be required for each user to easily access to AIS database system in order to share all of
the aeronautical data and information among relevant authorities on a real-time basis.
AIS database system must have web browser function which is worldwide standard for
computer network technology over IP (Internet Protocol), and realize data sharing related to
Search and Rescue. MET, NOTAM, and so on.
(8) International and Internal Data Exchange Function
AIS automation system will be required to have a function to exchange basic and static data
with other NOFs and domestic airports through AFTN or ATN. Also, mapping and chart data
including obstacles, routes, terminal procedures, airspace structure, etc. would also be
exchanged in future.
14.10
Global Navigation Satellite System (GNSS)
14.10.1 Definition
The term Global Navigation Satellite System (GNSS) is the generic name used by ICAO to
define any worldwide positioning and time-defining system that includes one or more satellite
constellations, aircraft receivers, and various integrity monitoring systems, including the
corresponding augmentation devices for meeting operational performance requirements.
GNSS augments navigational performances of the core satellites e.g. GPS, GLONASS and
Galileo to meet the Required Navigation Performance (RNP) for safety navigation of civil
aviation.
Worldwide services will be provided, at least in the immediate future, by the GPS and
GLONASS.
14.10.2 Components
(1)
Global Positioning System (GPS)
The GPS is a satellite-based radio navigation system that provides its users with high-precision
position and time information on almost any part on earth.
The space segment is composed of 24 satellites with a useful life of approximately 7 and a
half years, arranged in 6 orbits of four satellites each at an altitude of 20,200 km.
The control segment has 5 monitoring stations and 3 ground antennas. The monitoring stations
use a GPS receiver to track all satellites within its range and store distance data from satellite
signals. The information of the monitoring stations is processed at the master station to
determine the condition of the satellite clock and the orbit condition and to update the message
containing the data (used for navigation purposes) sent by the satellites. This updated
information is sent to the latter through ground antennas, which are also used to transmit and
receive information about the general condition of the system and its control. The user segment
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consists of the antenna and the processor-receiver for receiving and processing the navigation
solutions used to provide it with the precise position and time. The GPS position is based on
satellite measurements, for example, using distance measurements made by orbiting satellites
to obtain a precise position.
The GPS satellites transmit an extremely precise time signal that is compared by the GPS
receiver with the time in its own internal clock. The difference between the time signal
received from the satellite and the time on the receiver equipment is the time the signal takes to
travel from the satellite to the receiver. Since the speed of the signal is a known fact (speed of
light: approximately 297,000 km/sec.), the distance between the receiver and the satellite can
be estimated. In order for the system to function, time measurements must be very precise, as
must the clocks used. Within the satellites, that exactness is achieved through the use of
very-high-precision atomic clocks. Measurements from at least 4 satellites are needed to
establish a 3-D position and time fix. At least three satellites are needed to determine the
position in 2 dimensions if the altitude is known.
Precision depends upon the geometry of the satellites used. Five satellites with good geometry
are needed to monitor the integrity of the system. Each measurement will contain an error
produced by the existing difference between the time on the receiver clock and that of the
satellite. This error will be the same for all measurements; therefore, the receiver computer will
be able to make a mathematical correction that will allow all of these distance measurements to
intersect at a single point. Then the clock error can be calculated and the proper correction
made.
GPS satellites are positioned in very precise and predictable orbits. They orbit the earth every
12 hours and pass over some of the monitoring stations at least twice a day. These stations are
equipped to calculate satellite positions with precision and to uplink the corrected information
to them. They send information to the receiver on their position with respect to the centre of the
earth, together with the time signal.
The airborne receiver uses this information to calculate a position with respect to the surface of
the earth, which will be presented to the user in terms of latitude and longitude.
The exactness of this system makes it possible to obtain fixes with an error of 100 m (95%
probability) and with an error of 300 m (99.99% probability) on the horizontal plane, and with
a possibility of error of 156 m (95% probability) on the vertical plane when the selective
availability (S/A) is activated. The geodetic coordinate system it uses is the 1984 World
Geodetic System (WGS-84).
(2)
Errors
The United States Department of Defense declared the GPS precision for civil use as being +/100 m 95% of the time. But, like all other conventional navigation systems, the GPS is subject
to errors that can degrade its precision, including:
- ionospheric error;
- atmospheric error;
- selective availability;
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- clock error;
- receiver error;
- satellite ephemeris error; and
- position dilution of precision
The most significant error occurs when the satellite signal goes through the earth ionosphere.
This is a layer of electrically charged particles located approximately between 130 and 190 km
above the surface of the earth. As the GPS signal travels through the ionosphere, it is slowed
down in a proportion that varies according to the time of day, solar activity, and a series of
other elements. Ionospheric delays may be forecast and an average correction applied to the
GPS position; even so, there will still be some errors generated by this phenomenon. Another
error is caused when the signal goes through the atmosphere. The water vapor in the
atmosphere delays the GPS signal and also contributes to degrade the precision of the system.
There is another error that has been introduced directly into the system by the United States
Department of Defense. This error is known as selective availability.
Additional errors may include clock errors, receiver errors, and errors in satellite ephemeris
(position) data. Lastly, there is the error known as position dilution of precision (PDOP). The
errors existing in the system can be significantly increased, depending upon the geometry of
the satellites used to determine a position.
When the PDOP is factored in, errors of between 30 and 300 m can occur, depending upon
receiver type, relative satellite position, and extent of other errors.
(3)
Notices to airmen (NOTAMs)
When the GNSS (GPS component) is authorized as primary means of navigation in
oceanic/remote airspaces, a RAIM-capable airborne receiver is required.
RAIM requires that at least five satellites be visible so as to detect a faulty one. Even with the
24 satellites of the constellation in operation, there will be times when their geometry in space
will not be suitable to detect a failure in any one. Furthermore, it is sometimes necessary to
remove a satellite from service for maintenance.
It is very important for the pilots to know beforehand when the required number of satellites
will not be available for a given segment of the proposed flight route.
In the United States, the Department of Defense sends the FAA and the Coast Guard
information about any change in the number of operational GPS satellites. This is done at least
48 hours in advance. This information is entered in a database that can be used by aeronautical
information service personnel during preflight planning. This generic information about
satellites out of service must be converted, through an appropriate automation process, so that
pilots can use it in said planning. This will make them aware not only that a satellite will be out
of service, but also how that will affect the planned flight.
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(4)
Global orbiting navigation satellite system (GLONASS)
The Russian Federation has implemented the global orbiting navigation satellite system, its
concept quite similar to that of the United States system. It provides for space signals to be sent
to properly equipped users for precise determination of position, speed, and time. The space
segment consists of 24 satellites (21 operational + 3 standby) orbiting at an altitude of 19,100
Km, with an orbit period of 11 hours and 15 minutes.
They are distributed into 3 orbits of 8 satellites each with an operational life of 3 years (5 years
in improved versions).
The message transmitted from each satellite for navigation purposes consists of the coordinates
of the transmitting satellite, speed vector components, corrections to the time of the GLONASS
system, and information about satellite condition. To obtain a fix, a receiver must receive at
least 4 satellite signals, either simultaneously or in sequence, and must resolve 4 equations at
the same time for the three position and time components.
The ground segment fulfils satellite monitoring and control functions at the same time that it
selects the data to be modulated in the encoded signals sent for navigation purposes. This
segment includes the master station and monitoring and information delivery stations. The
measurement data from each monitoring station are processed at the master station and used to
compute the navigation data down-linked to satellites by relay stations.
The operation of the system requires precise synchronization of satellite clocks with the time of
the GLONASS system. To this end, the master station provides correction parameters.
The user segment (GLONASS receiver) automatically receives navigation signals from at least
four satellites Guidance Manual for the Training of Human Resources on the CNS/ATM
Systems 17 and measures their speed. Simultaneously, it selects and processes the navigation
message from the satellite signals. The computer of the receiver processes all input data and
calculates 3 coordinates, 3 speed components, and the precise time.
The precision of this system allows for 50 to 70 m exactness on the horizontal plane and 70 m
on the vertical plane (99.7% probability in both cases).
The geodetic coordinate system that it uses is called Earth Parameters 90 (PE-90).
14.10.3 The 1984 World Geodetic System (WGS-84)
The WGS-84 was developed to provide for more precision and continuing updating of geodetic
and gravitational data; also to offer means for interrelating positions based on various geodetic
systems or datum through a system of coordinates that consider a single earth centre as its fixed
system. The WGS-84 represents the model of a geocentric, geodetic, and gravitational earth
that uses data and technology available as of 1984. Such system allows the user to relate
geographic data, such as coordinates obtained from a source based on a local datum, with
another source (for example: map positions with coordinates obtained in real time by inertial
navigation systems). The WGS-84 is an ideal system for global navigation applications, such as
international air operations.
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In the static survey modality, the precision of geodetic latitude and longitude and geoids’
height of WGS-84 is within +/- 1 meter.
14.10.4 GNSS Implementation
(1)
Development stage
During this stage, the organizational aspects to be borne in mind and the basic requirements for
authorizing limited use of the GNSS are described. A GNSS implementation team is also
established. A development plan is designed to attain progressive objectives. That plan should
include a requirement to permit rapid but, at the same time, limited use of the system. It should
also determine the initial capability to be incorporated (en-route operations, non-precision
approaches, precision approaches, etc.).
(2)
Supplementary stage
This stage covers the requirements to be met for approval of the GNSS as supplementary
means of navigation. It identifies the topics of system certification and the creation of
suggested operating methods. It also identifies the tests and demonstrations that should be
conducted to gain operating experience. The corresponding authorizations and guidelines are
published and augmentations to basic GNSS signals are discussed and analyzed in this stage.
(3)
Primary stage
The objectives set in the development stage are attained in this stage. A check is made to see
whether the objectives have been attained with regard to the use of GNSS for the various
categories of precision approaches and the selected augmentation techniques are evaluated.
The steps followed for the certification and final approval of the system are also checked.
Needs are identified in terms of both air and ATS service procedures, and the necessary
publications are issued to disseminate and regulate the use of the GNSS. Lastly, follow-up
mechanisms are established to control the procedures.
14.10.5 Navigation Aid Performance Requirements
All navigation aids must fulfill four basic performance requirements in order to be certified:
continuity, availability, integrity, and precision.
(1)
Continuity
It is the ability of the entire system to carry out its function without interruption during the
planned operating period. The continuity risk is the probability that the system will be
interrupted and ceases to provide guidance information for the proposed operation.
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(2)
Availability
This is the ability of a navigation aid to transmit signals of the required quality most of the time.
This is a critical requirement in landing guidance and for this reason standby equipment is
added to the ground-based aids.
The GPS needs to have 4 satellites on the horizon simultaneously in order to obtain a 3-D
position fix, but this is not enough to provide a navigation solution with sufficient integrity.
(3)
Integrity
This is the ability of a navigation aid to warn the pilot that it has failed or is giving incorrect
bearings. GPS satellites are not monitored continuously and several hours can go by before a
failure is detected and corrected, although in fact most error warnings are issued within 30
minutes.
(4)
Precision
This is the ability of a navigation aid to guide the path of an aircraft within pre-defined
tolerances. The GPS component of the GNSS has a precision of 100 m on the horizontal plane
95% of the time. The signals available for civil users are, for security reasons, degraded 100 m
precision-wise using selective availability (S/A). It is estimated that GLONASS signals can be
manipulated in a similar fashion. The U.S. Air Navigation Plan sets the possible margin of
error of a GPS fix at +/- 100 horizontal meters by +/- 156 vertical meters, the latter being the
most critical value for consideration in the case of a precision approach.
It should also be borne in mind that a satellite fix in space is an ellipsoid in which the vertical
axis of error is almost 50% larger than the horizontal axis of error.
These percentages are very far from the minima allowed for precision approaches. To correct
them, augmentation or differential correction techniques have been developed.
14.10.6 The Three Navigation Systems
(1)
Supplementary navigation system
This is the navigation system that must meet the precision and integrity requirements, but not
the availability and continuity requirements.
Approval for using a supplementary navigation system in a given flight phase requires having a
sole means of navigation system on board.
(2)
Primary navigation system
This is the navigation system approved for a given operation or flight phase that must meet the
precision and integrity requirements, but not with those of availability and continuity. Safety is
achieved by limiting flights to specific periods of time and establishing certain procedural
restrictions.
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(3)
Sole means navigation system
This is the navigation system approved for a given operation or flight phase that must meet, for
that operation or flight phase, the four navigation system performance requirements: continuity,
availability, integrity, and precision.
14.10.7 Databases
Airlines and other organizations that provide flight planning and aeronautical chart services
maintain internal navigation databases, from which they extract the necessary data to plot flight
routes and to design aeronautical charts.
These databases should be compiled based on information supplied by States, in keeping with
ICAO Annex 15 Aeronautical Information Services”. Therefore, the States are responsible for
the precision of said information.
With the appearance on the market of flight management equipment (FMS), airlines need to
update, on a monthly basis, the on board data bases used for navigation purposes. This
information is taken from the central data base that these organizations keep.
14.10.8 Augmentations
The GPS (and presumably the GLONASS) does not have enough continuity, availability,
integrity, and precision to allow for its use as the sole means of navigation for all flight phases.
In order to meet operational 22 Guidance Manual for the Training of Human Resources on the
CNS/ATM Systems requirements, augmentations must be applied to basic GPS signals to
eliminate the errors they contain. Three basic categories of augmentations have been proposed:
airborne-based augmentation systems (ABAS), ground-based augmentation systems (GBAS),
and satellite-based augmentation systems (SBAS).
Conceptual System configuration is shown in Figure 14.10.1 System Configuration of GNSS:
Global Navigation Satellite System.
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Integrity, Accuracy, Continuity, Availability
Satellite Based Augmentation System
S B AS
Aircraft Based Augmentation System
AB AS
Geostationary Satellite
MT SAT
INMARSAT
RAIM: (Receiver Autonomous Integrity Monitor)
Fault Detection & Exclusion of faulty satellites
WAAS
MSAS
EGNOSS
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Ground Based Augmentation System
GBAS
VDB : VHF Data Broadcast
Ground Earth Station
Master Control Station
Reference Station
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Figure 14.10.1
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Ground Monitor Station
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Augmentation of Core Navigation Satellites regarding
RNP (Required Navigation Performance) as for
Core Navigation Satellite
GPS
GLONASS
Galileo
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(1)
Airborne-based augmentation systems (ABAS)
•
Receiver autonomous integrity monitoring (RAIM)
This technique can be used if there are more than 4 satellites with the appropriate geometry
within range of the receiver. With 5 satellites, 5 independent positions can be computed; if
these do not match, the receiver infers that one or more of the satellites is supplying incorrect
information and a warning light will turn on the equipment panel.
If there are 6 or more satellites within range, more independent positions can be calculated and
the receiver will be able to identify the defective satellite and exclude it from positioning
calculations.
The RAIM technique may be assisted by a process known as barometric aiding. Aircraft
barometric altitude information is taken from the GPS receiver, which can simulate a satellite
placed directly over the user. With this process, the requirement for 5 or 6 satellites can be
reduced to 4 or 5, respectively.
•
Aircraft autonomous integrity monitoring (AAIM)
Other types of on-board augmentations can be used. An INS can replace the GNSS at times
when their antennas are shielded (during turns, for example) or when the number of satellites
within range of the receiver is inadequate.
Other airborne-based augmentation techniques can include a more precise time reference, a
given combination of sensor input information through filtering techniques, etc.
(2)
Ground-based augmentation systems (GBAS)
These systems are used to enhance the continuity, availability, integrity, and precision of GNSS
signals within a reduced geographic area.
They consist of a ground monitoring station whose location is known with precision. This
station evaluates the information received from GNSS satellites, detects clock and other errors,
and sends a corrective signal to airborne receivers through a VHF data link.
Precisions on the order of 5 meters can be achieved with ground-based augmentation systems,
which make them suitable for Cat. II/III instrument approaches. The advantage of the GBAS
lies in the fact that it can serve all airport runways within a range of 30 nautical miles from the
ground monitoring station.
•
Special Category 1 ILS (SCAT-1) equipment
A version of the GBAS known as SCAT-1 (Special Category 1 ILS) has been developed in the
United States. This SCAT-1 equipment is certified for each specific airport and for each type of
aircraft. It must also be compatible with airborne avionics, making its use very specific and not
open to general aviation.
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(3)
Satellite-based augmentation systems (SBAS)
The GBAS will not be able to provide coverage for all flights because of its range limitations.
An effective means of overcoming this limitation has been devised, using geostationary
satellites to transmit messages to correct GNSS signals on a broad geographic area.
1)
European geostationary navigation overlay service (EGNOS)
This system is based on the provision of three services combined in a single signal: range
expansion, whereby a GPS-type signal is broadcast by the transponder, giving the satellite a
broader range; geostationary integrity channel, through which information is provided about
the status of all GPS and GLONASS satellites; and broad area differential corrections, with
information for correcting errors generated when GPS signals cross the ionosphere, as well as
satellite clock errors.
a) Spatial navigation segment
This segment consists of the GPS constellation, the GLONASS constellation, and the
geostationary satellites (usually two).
b) Ground segment
This segment is composed of:
- ranging and integrity monitoring stations (RIMS), which act as data collection points. They
also transmit the data collected from the MCC.
- master control centre (MCC), which includes:
- central control facilities (CCF), that monitor and control the system;
- central processing facilities (CPF), that compute, distribute, and validate the transmission
of adjustments and data corrections. They also ensure end-to-end integrity of the
corrections transmitted;
- navigation land earth stations (NLES), which are used to modulate the message generated
by the CPF, synchronize the signal and uplink the data to the geostationary satellites;
- a communication network, that is needed to interconnect all of the elements of the ground
segment.
c) Functions
- Ranging capability over each GEO signal;
- Dissemination of navigation data concerning the satellites used (GPS, GLONASS, and
GEO), which are used to control the integrity in the so-called GIC (ground integrity
channel) function and to enhance integrity; and
- The WAD (wide area differential) function to enhance precision, which includes
information about ionospheric delays;
These services give rise to three levels of service in the AOC:
- Service level 1, RANGING, which will improve the GPS navigation function, based on the
transmission of a GPS-type signal, which will increase the availability of the navigation
service (positioning and RAIM); EGNOS will give two ranging signals through the GEO
INMARSAT III AORE and IOR;
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-
-
Service level 2, GIC, which will add to the improvements brought about by Service level 1,
an enhancement of the integrity function, based on the transmission of additional integrity
data supplied from the ground, over the GPS, GLONASS, and GEO; and
Service level 3, WAD, which will give users the same service as Level 2 plus the
transmission of differential corrections and ionospheric delay data in order to improve the
precision services provided by the GPS.
The functions that EGOS will furnish to cover the cited services are:
- Data collection;
- Determination of satellite orbits;
- Determination of corrections to be applied to each satellite;
- Provision of data on the integrity of each satellite;
- Determination of ionospheric corrections;
- Independent verification of the data;
- Independent data verification;
- Provision of unified time to the systems network;
- Provision of ranging service in the signals in space and dissemination of navigation
messages;
- Provision of system communications; and
- Monitoring and control.
d) EGNOS receiver
This receiver will be capable of receiving GPS/GLONASS signals and of processing the
adjustment data from the GNSS integrity channel and the differential corrections sent by
geostationary satellites. It will also use a RAIM algorithm to complete the integrity verification.
The EGNOS receiver is also expected to be interoperable with the other satellite-based
augmentation systems (WAAS, MTSAT, etc.).
2)
Multifunctional transport satellite (MTSAT)
The Japans is implementing a version of the SBAS known as MTSAT augmentation system
(MSAS). MTSAT has communication and navigation capabilities. The two-way
communication link capability enables message relaying between the pilot and the air traffic
control unit and to send automatic ADS aircraft position reports to the appropriate ground unit.
Pilot-controller two-way communications can include data messages, with one satellite acting
as relay. This allows for the exchange of large amounts of data over a relatively short period of
time while avoiding errors and enabling a highly efficient service.
The overlay and differential augmentation capabilities of the MTSAT will improve the
information supplied by the GPS. In order to determine its position, an aircraft needs at least
four GPS satellites with the appropriate geometry; but these satellites are not geostationary and,
as a result, there are times and positions when that information cannot be obtained. The overlay
capability of the MTSAT, which is geostationary, is capable of supplementing the GPS by
providing unique position information.
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The differential capability monitors GPS satellite operation from the earth and informs aircraft
of any problem, while correcting any position information obtained through the GPS.
With these functions, air traffic controllers are able to determine the position of an aircraft
precisely, thus increasing the capacity of a given airspace.
There are also advantages for aircraft flying at low altitudes that are presently unable to
maintain an efficient radio link due to interruptions caused by geographic obstacles.
Consequently, the MTSAT will allow routes to be established freely, thus providing flights
with more economic and efficient paths.
3)
Wide area augmentation system (WAAS)
The United States is implementing a version of the SBAS known as the wide area
augmentation system (WAAS). The WAAS fulfils 3 functions:
-
Integrity for all flight phases through CAT I landings;
Adjustment signals to improve availability for all flight phases through CAT I landings;
and
Improved precision with DGPS through CAT I landings.
The WAAS network will consist of 24 wide area reference stations, to be installed in
predetermined positions, which will evaluate GPS satellite signals.
This information will be sent to 2 wide area master stations that calculate the correction
algorithms and evaluate the reliability and integrity of GPS signals sent by the satellite within
range of the reference stations. The master station will format the information in a message that
it will send to the corresponding geostationary satellite of the 3 that cover the United States.
This satellite will relay the information to airborne GPS receivers that are capable of accepting
such corrections.
14.10.9 Benefits Of The New Navigation System
The availability of an improved guidance and position capability in any part of the world will
enhance operational efficiency, reducing flight time and the fuel required through navigation
that is more precise than it is today and, where applicable, the adoption of routes requested by
the user. Flights with some weight limitation can benefit from the reduction of fuel
requirements, including contingency reserves, thus increasing payload and profits.
Consideration must also be given to the availability of non-precision guidance for runways
lacking ground navigation aids or that are served by unreliable navigation aids; this will reduce
delays, alternates, over flights and cancellations due to bad weather. The availability of a
GNSS-supported precision approach capability, whether through ground-based or
satellite-based augmentation systems, coupled with airborne ones, will also offer operational
advantages over existing equipment.
Consequently, the capability of providing approach guidance for more airports could attract
traffic from those where delays due of congestion are common. By reducing such delays,
operators will save flight time and required fuel.
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Use of the GNSS 4-D navigation capability will permit more precise positioning of incoming
flights over an approach fix. The ability to comply with a required time of arrival (RTA) will
contribute to increase airport capacity and also to reduce delays.
Eventual use of the GNSS for all flight phases will result in savings for operators due to the
reduction of airborne equipment types. It will also reduce maintenance and capital costs.
Advanced integration techniques with inertial reference systems (IRS) will make it possible to
operate with less expensive inertial sensors. The availability of satellite navigation will enable
the gradual deactivation and de-phasing of ground aids. This will reduce costs, at least in the
medium and long terms, allowing service providers and users significant savings.
(1)
Expected operational benefits
Progressive implementation of satellite navigation will be required in order to take early
advantage of GNSS operational benefits.
The use of GPS as a supplementary means of en-route navigation and as a primary means of
navigation over oceanic/remote airspaces, as well as overlay approaches and autonomous GPS
approaches provide users with operational advantages by giving them direct contact with the
GNSS. Regarding the relevant bodies, this is an excellent opportunity for gaining experience in
the operation of the GPS equipment, in-flight inspection procedures, application of the
WGS-84, etc.
1)
Use of the GPS as a supplementary means of en-route navigation
The global positioning system (GPS) can be used as a supplementary means of IFR en-route
navigation. The GPS receiver used for IFR flights should meet the technical requirements
specified in the FAA Technical Standard Order (TSO) C-129a and should be installed in
keeping with FAA Circular AC-20-138.
The GPS IFR receivers possess the airborne RAIM augmentation technique and have a built-in
navigation database, which cannot be manually accessed during flight in order to avoid
insertion errors.
2)
Use of the GPS as primary means of navigation in oceanic/ remote airspaces
International Civil Aviation Organization Circular NE 267-AN/159 Guidelines for the
Introduction and Operational Use of the Global Navigation Satellite System” stipulates in
paragraph 6.1.1, item C) that in light of the availability of an improved navigation integrity,
together with reduced availability requirements for flights over oceanic airspaces, the use of
satellite-based systems would be allowed as the primary means of navigation for this flight
phase”.
Aircraft will have to be equipped with receivers that comply with the FAA TSO C-129a
standard and must also meet the requirements of FAA Notice N.8110.60 GPS as a primary
means of navigation for oceanic/remote operations”.
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3)
Overlay approaches
In this type of non-precision approaches, the final approach segment of the procedure is
extracted from the GPS receiver, instead of being based on ground radio aid bearings. An
overlay program is not complicated to carry out, for it only requires one airborne
C-129-compliant GPS receiver. The first step consists of selecting the non-precision
approaches to be overlaid. There should be only one approach per runway and it should be the
one that is most closely aligned with the final path.
The coordinates of the points that mark the beginning of the approach segments to be overlaid
(IAF, IF, FAF, and MAPt.) will then be converted to the WGS-84 Geodetic System. A database
for the overlay approach will have to be developed, with the points surveyed in the WGS-84,
and sent to a database provider for the preparation of a data card in keeping with FAA Circular
AC NE 97-2 Data base standardization for the GPS overlay program”. The provider should be
informed of the type of equipment to be used, since card formats differ according to the type of
equipment involved.
The requirement for a printed database is intended to keep the pilot from programming the
approach manually and thereby avoid data input errors. The receivers are equipped with an
automatic sequence device to protect the integrity of the database. No data can be entered once
the approach mode has been selected. The IAF will appear on the equipment screen, followed
automatically by all of the points that define the approach segments, up to the missed approach
point (MAPt).
Once it receives the data card, the Flight Inspection Department will use the procedure in flight
in order to validate it.
4)
GPS stand-alone approaches
GPS non-precision stand-alone approaches that are not the overlay of a traditional approach are
the step following the overlay approaches.
The sequence of waypoints that define the procedure is encoded in the airborne GPS receiver
(129a standard compliant) database. These points include the initial approach fix (IAF), the
intermediate approach fix (IF), the final approach fix (FAF), the missed approach point (MAPt),
the missed approach turn fix, and the missed approach holding fix. This sequence of waypoints
that appears on the airborne equipment screen should be identical to the sequence shown on the
GPS approach card.
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