TECHNICAL UNIVERSITY OF KOŠICE
Department of Electronic and Multimedia Communication
List of system for radio determination of position
Miroslava Trojanovičová
Applied Informatics
Summer semester 2012/2013
1. EGNOS
1.1.
Introduction
The European Geostationary Navigation Overlay Service Egnos is a satellite based
augmentation system (SBAS) developed by the European Space Agency, the European
Commission and EUROCONTROL. It supplements the GPS, GLONASS and Galileo
systems by reporting on the reliability and accuracy of the positioning data. The official
start of operations was announced by the European Commission on 1 October 2009. The
system started its initial operations in July 2005, showing outstanding performances in terms
of accuracy (better than two meters) and availability (above 99%); and it was certified for use
in safety of life applications in March 2011. An EGNOS Data Access Service is also available
since July 2012.
Consisting of three geostationary satellites and a network of ground stations, EGNOS
achieves its aim by transmitting a signal containing information on the reliability and
accuracy of the positioning signals sent out by GPS. It allows users in Europe and beyond to
determine their position to within 1.5 meters.
1.2.
Message
The EGNOS signal-in-space is broadcast by Geostationary Earth Orbit (GEO) satellites in
the L1 frequency, centered at 1575.42 MHz. The raw navigation message contains 500
bits. These raw data are ½ convolutional encoded with a FEC code, which means that 250
bits of information are available every second at user level. The 250-bit message has different
parts, including an 8-bit preamble and 24 ancillary bits to include redundancy and error
checking within the message.
1.3.
Use of EGNOS
EGNOS is mostly designed for aviation users which enjoy unperturbed reception of
direct signals from geostationary satellites up to very high latitudes. The use of EGNOS on
the ground, especially in urban areas, is limited due to relatively low elevation of
geostationary satellites: about 30° above horizon in central Europe and much less in the North
of Europe.
1.4.
Satellites
EGNOS satellites AOR-E (PRN120) and the IOR-W (PRN 126) is used for EGNOS
Operations and the ESA ARTEMIS satellite (PRN 124) is currently used by Industry to
perform various tests on the system.
1.5.
Ground stations
More than 40 ground stations are linked together to create EGNOS network which
consists: 34 RIMS (Ranging and Integrity Monitoring Stations): receiving signals from US
GPS satellites, 4 MCC (Mission Control Centers): data processing and differential corrections
counting and 6 NLES (Navigation Land Earth Stations): accuracy and reliability data sending
to three geostationary satellite transponders to allow end-user devices to receive them.
2. WAAS
2.1.
Introduction
The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the
Federal Aviation Administration to augment the Global Positioning System (GPS), with the
goal of improving its accuracy, integrity, and availability. Essentially, WAAS is intended to
enable aircraft to rely on GPS for all phases of flight, including precision approaches to any
airport within its coverage area. The WAAS was jointly developed by the United States
Department of Transportation (DOT) and the Federal Aviation Administration (FAA) as part
of the Federal Radionavigation Program beginning in 1994.
2.2.
Ground segments
WAAS is composed of three main segments: the Ground segment, Space segment, and
User segment. The ground segment is composed of multiple Wide-area Reference Stations
(WRS) which collect GPS data, 3 WAAS Master Station (WMS): the WRS collected data are
forwarded to the WAAS Master Station (WMS) via a terrestrial communications network. At
the WMS, the WAAS augmentation messages are generated, 6 Ground Uplink Stations
(GUS): they are in charge of the transmission of the WAAS messages generated by WMS
stations to the navigation payloads on Geostationary communications satellites for
rebroadcast to the users, 2 Operational Control Centers (OCC), used to monitor the system
performance and to carry out the necessary corrective and periodic maintenance operations.
As of October 2007 there were 38 WRSs: twenty in the contiguous United States
(CONUS), seven in Alaska, one in Hawaii, one in Puerto Rico, five in Mexico, and four in
Canada, the WRS stations.
City
ICAO airport code
Location
Elevation
Bethel, Alaska
PABE
60.787898226ºN 161.841705626ºW 52.202 m
Billings, Montana
KBIL
45.803726761ºN 108.539727967ºW 1112.261 m
Barrow, Alaska
PABR
71.282786134ºN 156.789914977ºW 15.581 m
Cold Bay, Alaska
PACD
55.200376531ºN 162.718528459ºW 53.652 m
Fairbanks, Alaska
PAFA
64.809686817ºN 147.847403468ºW 149.888 m
Honolulu, Hawaii
PHNL
21.312783159ºN 157.920876933ºW 24.922 m
Juneau, Alaska
PAJN
58.362530123ºN 134.585495176ºW 16.024 m
Mérida, Yucatán (Mexico)
MMMD
20.931919004ºN 89.662872977ºW
29.157 m
Mexico City (Mexico)
MMMX
19.431653193ºN 99.068389463ºW
2236.638 m
Puerto Vallarta, Jalisco (Mexico)
MMPR
20.679034758ºN 105.249200735ºW 11.077 m
San José del Cabo, Baja California (Mexico)
MMSD
23.160416093ºN 109.717667886ºW 104.286 m
Tapachula, Chiapas (Mexico)
MMTP
14.791340027ºN 92.367991216ºW
Kotzebue, Alaska
PAOT
66.887352636ºN 162.611355542ºW 10.911 m
Iqaluit, Nunavut (Canada)
CYFB
63.731446844ºN 68.543393603ºW
9.998 m
Gander, Newfoundland and Labrador (Canada)
CYQX
48.966447828ºN 54.597532074ºW
146.891 m
Winnipeg, Manitoba (Canada)
CYWG
49.900606898ºN 97.259280113ºW
222.046 m
Goose Bay, Newfoundland and Labrador(Canada) CYYR
53.308720955ºN 60.419401330ºW
37.842 m
Albuquerque, New Mexico
KZAB
35.173560874ºN 106.567308273ºW 1620.154 m
Anchorage, Alaska
PAZA
61.229174557ºN 149.780364869ºW 80.654 m
Aurora, Illinois
KZAU
41.782616622ºN 88.331308050ºW
195.922 m
Nashua, New Hampshire
KZBW
42.735705193ºN 71.480378445ºW
39.141 m
Leesburg, Virginia
KZDC
39.101556058ºN 77.542750106ºW
80.085 m
Longmont, Colorado
KZDV
40.187286655ºN 105.127181633ºW 1541.389 m
Fort Worth, Texas
KZFW
32.830614792ºN 97.066488376ºW
155.604 m
Houston, Texas
KZHU
29.961833882ºN 95.331462501ºW
10.947 m
Hilliard, Florida
KZJX
30.698824796ºN 81.908178358ºW
2.141 m
Olathe, Kansas
KZKC
38.880140378ºN 94.790729104ºW
305.814 m
Palmdale, California
KZLA
34.603503189ºN 118.083872233ºW 763.546 m
Salt Lake City, Utah
KZLC
40.786007936ºN 111.952158417ºW 1287.420 m
Miami, Florida
KZMA
25.824644475ºN 80.319246501ºW
-7.882 m
Memphis, Tennessee
KZME
35.067423639ºN 89.955391700ºW
68.788 m
54.922 m
Farmington, Minnesota
KZMP
44.637444415ºN 93.152039309ºW
262.667 m
Ronkonkoma, New York
KZNY
40.784293219ºN 73.097181151ºW
6.108 m
Fremont, California
KZOA
37.543019928ºN 122.015922570ºW -3.459 m
Oberlin, Ohio
KZOB
41.297135898ºN 82.206391657ºW
Auburn, Washington
KZSE
47.286919203ºN 122.188372739ºW 82.128 m
San Juan, Puerto Rico
TJZS
18.431249167ºN 65.993480433ºW
-28.547 m
Hampton, Georgia
KZTL
33.379671593ºN 84.296678124ºW
261.142 m
224.115 m
Table 1. Destination of WRSs
2.3.
Space segments
The space segment consists of multiple geosynchronous communication satellites which
broadcast the correction messages generated by the WAAS Master Stations for reception by
the user segment. The satellites also broadcast the same type of range information as normal
GPS satellites, effectively increasing the number of satellites available for a position fix. The
space segment consists of three commercial satellites: Inmarsat-4 F3, Telesat's Anik F1R, and
Intelsat's Galaxy 15. The original two WAAS satellites, named Pacific Ocean Region (POR)
and Atlantic Ocean Region-West (AOR-W), were leased space on Inmarsat III satellites.
These satellites ceased WAAS transmissions on July 31, 2007. With the end of the Inmarsat
lease approaching, two new satellites (Galaxy 15 and Anik F1R) were launched in late 2005.
Galaxy 15 is a PanAmSat, and Anik F1R is a Telesat.
2.4.
User segments
The user segment is the GPS and WAAS receiver, which uses the information broadcast
from each GPS satellite to determine its location and the current time, and receives the
WAAS corrections from the Space segment.
2.5.
Signal
The Wide Area Augmentation System (WAAS) provides ranging signals transmitted by
GEO satellites, differential corrections on the wide area and additional parameters aimed to
guarantee the integrity of the GNSS user: GEO Ranging: transmission of GPS-like L1
signals from GEO satellites to augment the number of navigation satellites available to the
users, Wide Area Differential (WAD): differential corrections to the existing GPS and GEO
navigation services computed in a wide area to improve navigation services performance.
This includes corrections to the satellite orbits and clocks, as well as information to estimate
the delay suffered from the signal when it passes through the ionosphere and GNSS/Ground
Integrity Channel (GIC): integrity information to inform about the availability of GPS and
GEO safe navigation service.
3. MSAS
3.1.
Indroduction
Multi-functional Satellite Augmentation System (MSAS) is a Japanese SBAS (Satellite
Based Augmentation System), i.e. a satellite navigation system which supports differential
GPS (DGPS) designed to supplement the GPS system by reporting (then improving) on the
reliability and accuracy of those signals. Tests had been accomplished successfully, MSAS
for aviation use was commissioned on September 27, 2007. A similar service is provided in
North America by Wide Area Augmentation System (WAAS), and in Europe by European
Geostationary Navigation Overlay Service (EGNOS).
3.2.
Space segments
Space segment contain two satellites: MTSAT-1R and MTSAT-2. MTSAT-1R (also
known as Himawari 6) was successfully launched on a H-IIA on February 26, 2005. It was
built by Space Systems/Loral. MTSAT-2 (also known as Himawari 7) was built by Mitsubishi
and successfully put in orbit on February 18, 2006. Their lifespan is planned of five years.
Both satellites, MTSAT-1R and MTSAT-2, are controlled by Kobe MCS station and
Hitachiota MCS, respectively.
Satellite Name & Details
NMEA / PRN
Location
MTSAT-1R
NMEA #42 / PRN #129
140°E
MTSAT-2
NMEA #50 / PRN #137
145°E
Table 2. Satellites of MSAS
3.3.
Ground segments
The MSAS Ground Segment is composed of four Ground Monitor Station (GMS) that
collect information on the GPS and MTSAT signals. They are placed on Sapporo, Tokyo,
Fukuoka and Naha. The GMS stations send their data to two Master Control Station (MCS) in
Kobe and Hitachiota, which compute precise differential corrections and integrity bounds and
send them to the MTSAT satellites for rebroadcast to the User Segment. The MSAS Ground
Segment is completed with two Monitor and Ranging Station (MRS) in Hawaii (USA) and
Canberra (Australia), whose purpose is primarily the correct orbit determination of the
MTSAT satellites, and they also work as GMS stations.
3.4.
User segments
The MSAS user segment is the GPS and SBAS-enabled receiver, which uses the
information broadcast from each GPS satellite to determine its location and the current time,
and receives the MSAS corrections from the MTSAT satellites. MSAS receivers design is
identical to those designed for WAAS.
3.5.
MTSAT
Multifunctional Transport Satellites (MTSAT) are a series of weather and aviation control
satellites. They are geostationary satellites owned and operated by the Japanese Ministry of
Land, Infrastructure and Transport and the Japan Meteorological Agency (JMA), and provide
coverage for the hemisphere centered on 140° East; this includes Japan and Australia who are
the principal users of the satellite imagery that MTSAT provides.
4. VOR
4.1.
Introduction
VHF omnidirectional radio range (VOR), is a type of short-range radio navigation system
for aircraft, enabling aircraft to determine their position and stay on course by receiving radio
signals transmitted by a network of fixed ground radio beacons, with a receiver unit. It uses
radio frequencies in the very high frequency (VHF) band from 108 to 117.95 MHz.
Developed in the US beginning in 1937 and deployed by 1946, VOR is the standard air
navigational system in the world, used by both commercial and general aviation.
4.2.
How it works?
A VOR ground station sends out a master signal, and a highly directional second signal
that varies in phase 30 times a second compared to the master. This signal is timed so that the
phase varies as the secondary antenna spins, such that when the antenna is 90 degrees from
north, the signal is 90 degrees out of phase of the master. By comparing the phase of the
secondary signal to the master, the angle (bearing) to the station can be determined. This
bearing is then displayed in the cockpit of the aircraft, and can be used to take a fix as in
earlier radio direction finding (RDF) systems, although it is, in theory, easier to use and more
accurate. This line of position is called the "radial" from the VOR. The intersection of two
radials from different VOR stations on a chart provides the position of the aircraft. VOR
stations are fairly short range: the signals have a range of about 200 miles.
VOR stations broadcast a VHF radio composite signal including the station's identifier,
voice (if equipped), and navigation signal. The identifier is typically a two- or three-letter
string in Morse code. The voice signal, if used, is usually the station name, in-flight recorded
advisories, or live flight service broadcasts.
5. DME
Distance measuring equipment (DME) is a transponder-based radio navigation technology
that measures slant range distance by timing the propagation delay of VHF or UHF radio
signals. Aircraft use DME to determine their distance from a land-based transponder by
sending and receiving pulse pairs – two pulses of fixed duration and separation. The ground
stations are typically co-located with VORs. A typical DME ground transponder system for
en-route or terminal navigation will have a 1 kW peak pulse output on the assigned UHF
channel. A low-power DME can also be co-located with an ILS glide slope antenna
installation where it provides an accurate distance to touchdown function, similar to that
otherwise provided by ILS Marker Beacons. The DME system is composed of a UHF
transmitter/receiver (interrogator) in the aircraft and a UHF receiver/transmitter (transponder)
on the ground.
6. REFERENCIES
http://en.wikipedia.org/wiki/European_Geostationary_Navigation_Overlay_Service
http://www.navipedia.net/index.php/EGNOS_Signal_Structure
http://www.egnos-pro.esa.int/index.html
http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System
http://www.navipedia.net/index.php/WAAS_Signal_Structure
http://en.wikipedia.org/wiki/Multi-functional_Satellite_Augmentation_System
http://navipedia.net/index.php/MSAS_Space_Segment
http://www.navipedia.org/index.php/MSAS_Ground_Segment
http://en.wikipedia.org/wiki/VHF_omnidirectional_range
https://en.wikipedia.org/wiki/Distance_measuring_equipment