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BeiDou Space Segment
| COMPASS | |
|---|---|
| Title | BeiDou Space Segment |
| Author(s) | GMV |
| Level | Basic |
| Year of Publication | 2011 |
The Compass Navigation Satellite System (CNSS), also named BeiDou-2,[1] is China’s second-generation satellite navigation system that will be capable of providing positioning, navigation, and timing services to users on a continuous worldwide basis.[1][2]
Although the upgrade of its regional navigation system towards a global solution started in 1997, the formal approval by the Government of the development and deployment of BeiDou-2/CNSS was done in 2004.[1] The system is currently under development evolving from a regional system called BeiDou-1, and in the first phase will provide high-accuracy positioning services for users in China and its neighboring regions by 2012.[1] In a second stage, the system will evolve to provide global navigation services by 2020, similarly to the GPS, GLONASS or Galileo systems.[1]
As of August 2011, nine satellites for Compass have been launched, the first eight of which completed the deployment foreseen for the first phase of BeiDou-2.[1][3][4]
COMPASS Space Segment
The COMPASS Space Segment will consist of a constellation of 35 satellites, which include 5 geostationary orbit (GEO) satellites and 30 non-GSO satellites; 27 in Medium Earth Orbit (MEO) and 3 in Inclined Geosynchronous Orbit (IGSO), which will offer complete coverage of the globe.[3][2]
The system is to be deployed in two stages; the launches for the first phase will be completed by 2012[1] and will consist of 14 satellites serving the Asia-Pacific region.[3] The global navigation system should be finished by 2020.[1]
As of April 2011, eight satellites for Compass have been launched. According to Globaltimes.cn[4], "the eighth Beidou satellite marks the completion of basic function of Beidou (Compass) Navigation Satellite System and will collaborate with five navigation satellites launched last year to establish a navigating system of three GEO (geostationary orbit) satellites plus three IGSO (Inclined Geo Synchronous orbit) satellites. The system will be able to provide services to most regions in China after a period of orbiting running tests and system integration."
| Date | Launcher | Satellite | Orbit | Usable | System |
|---|---|---|---|---|---|
| 4/14/2007 | Long March 3A (LM-3A) | Compass-M1 | MEO ~21,500 km | Testing only | Compass |
| 4/15/2009 | Long March 3C (LM-3C) | Compass-G2 | GEO Drifting | No | |
| 1/17/2010 | LM-3C | Compass-G1 | GEO 144.5°E | Yes | |
| 6/2/2010 | LM-3C | Compass-G3 | GEO 84°E | Yes | |
| 8/1/2010 | LM-3A | Compass-IGSO1 | IGSO 118°E incl 55° | Yes | |
| 11/1/2010 | LM-3C | Compass-G4 | GEO 160°E | Yes | |
| 12/18/2010 | LM-3A | Compass-IGSO2 | IGSO 118°E incl 55° | Yes | |
| 04/10/2011 | LM-3A | Compass-IGSO3 | IGSO 118°E incl 55°, 200~35,991km | Yes |
The nominal constellation includes 35 satellites, 5 GEOs, 3 IGSOs and 27 MEOs. The number of IGSO orbits is 3, with one IGSO per plane. The intersection node is 118E. The MEOs are deployed as a Walker constellation; 24 MEOs in 3 planes plus 3 spares. The orbital parameters of the final constellation are shown in the following table:[3]
| Orbit parmts. | GEO | IGSO | MEO |
|---|---|---|---|
| Semi-Major Axis (Km) | 42164 | 42164 | 27878 |
| Eccentricity | 0 | 0 | 0 |
| Inclination (deg) | 0 | 55 | 55 |
| RAAN (deg) | 158.75E, 180E, 210.5E, 240E,260E | 218E,98E,338E | -- |
| Argument Perigee | 0 | 0 | |
| Mean anomaly (deg) | 0 | 218E:0,98E:120,338E:240 | |
| # Sats | 5 | 3 | 27 |
| # Planes | 1 | 3 | 3 |
Notes
References
- ^ a b c d e f g h Compass Satellite Navigation System (Beidou), on Sinodefence.com, updated on August 6th, 2011.
- ^ a b COMPASS Navigation system in Wikipedia
- ^ a b c d China Satellite Navigation Office, Development of BeiDou Navigation Satellite System, Munich Satellite Navigation Summit, 2011.
- ^ a b China completes basic Beidou (Compass) Navigation Satellite System, 2011-04-10 by Globaltimes.cn
- ^ Beidou Navigation System in Wikipedia