AGRICULTURE
BeiDou Navigation Satellite System (China)
The Chinese GNSS is known as the BeiDou Navigation Satellite System (BDS).
Phase 2 of the BeiDou system (BDS-2) officially became operational in December 2012, providing coverage for the Asia Pacific region. Initially, the regional BeiDou space segment had five Geostationary Earth Orbit (GEO)2 satellites, five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites.
Phase 3 of the BeiDou system (BDS-3) became fully operational in 2020, and BeiDou now provides global coverage with enhanced regional coverage. As of 2021, the space segment consists of a constellation of 45 satellites, as shown in Table 5 and Table 6.
BeiDou signals
The BeiDou signals, based on CDMA technology, are summarised in Table 7 and Table 8.
| Satellites | 2 GEO | 7 IGSO | 3 MEO |
|---|---|---|---|
| Orbital inclination | – | 55 degrees | 55 degrees |
| Orbit radius | 35,787 km (22,237 miles) |
35,787 km (22,237 miles) |
21,528 km (13,377 miles) |
| Satellites | 2 GEO | 4 IGSO | 26 MEO |
|---|---|---|---|
| Orbital planes | – | – | 3 |
| Orbital inclination | – | 55 degrees | 55 degrees |
| Orbit radius | 35,787 km (22,237 miles) |
35,787 km (22,237 miles) |
21,528 km (13,377 miles) |
| Designation | Frequency | Description |
|---|---|---|
| B1I | 1561.098 MHz | B1I provides both public service signals and restricted service signals. |
| B2I | 1207.140 MHz | B2I provides both public service signals and restricted service signals. |
| B3I | 1268.520 MHz | B3I provides both public service signals and restricted service signals. |
| Designation | Frequency | Description |
|---|---|---|
| B1I | 1561.098 MHz | B1I provides both public service signals and restricted service signals. |
| B1C | 1575.42 MHz | B1C provides public service signals. GEO satellites will broadcast BDSBAS corrections on B1C. |
| B2a | 1176.45 MHz | B2A provides public service signals. GEO satellites will broadcast BDSBAS corrections on B2a. |
| B2b | 1207.140 MHz | B2b provides short message communication services, international search and rescue service and PPP service. |
| B3I | 1268.520 MHz | B3I provides both public service signals and restricted service signals. |
2 A geosynchronous orbit has an orbital period matching the Earth’s sidereal rotation period. This synchronisation means that for an observer at a fixed location on Earth, a satellite in a geosynchronous orbit returns to exactly the same place in the sky at exactly the same time each day. The term geostationary is used to refer to the special case of a geosynchronous orbit that is circular (or nearly circular) and at zero (or nearly zero) inclination, that is, directly above the equator. Satellites in geostationary orbits appear stationary at one location at all times. ↩
