BeiDou

BeiDou Navigation Satellite System (China)

China has started the implementation of a GNSS system known as BeiDou Navigation Satellite System (BDS). The system is being implemented in two phases: the initial phase provides regional coverage, while the second phase will provide global coverage.

The initial phase of the BeiDou system officially became operational in December 2012, providing coverage for the Asia Pacific region. The regional BeiDou space segment has five Geostationary Earth Orbit (GEO) satellites, five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites (summarized in Table 6).

The second phase of the BeiDou system is planned to be completed by the end of 2020 and will provide global coverage with enhanced regional coverage. The space segment will consist of a constellation of 5 GEO, 3 IGSO and 27 MEO satellites, as shown in Table 7.

Table 6: Regional BeiDou Satellite Constellation

Satellites 5 Geo 5 IGSO 4 MEO
Orbital Inclination - 55 degrees 55 degrees
Orbit Radius 35,787 km 35,787 km 21,528 km

Table 7: Planned Global BeiDou Satellite Constellation

Satellites 5 GEO 3 IGSO 27 MEO
Orbital Planes - - 3
Orbital Inclination - 55 degrees 55 degrees
Orbit Radius 35,787 km 35,787 km 21,525 km


BeiDou Signals

The BeiDou signals, based on CDMA technology, are summarized in Table 8. Three levels of service will be provided:

  • Public service for civilian use and free to users. The public service provides position accuracy of 10 metres, velocity accuracy within 0.2 metres per second and timing accuracy of 10 nanoseconds.
  • Licensed service is available only to users who have obtained a subscription. The licensed service improves position accuracy to 2 metres. This service also provides bidirectional short messaging (120 Chinese characters) and provides information about the system status.
  • Restricted military service, more accurate than the public service, also provides system status information and military communications capability.

Table 8: BeiDou Signal Characteristics

Designation Frequency Description
B1 1561.098 MHz B1 provides both public service signals and restricted service signals.
B2 1207.140 MHz B2 provides both public service signals and restricted service signals.
B3 1268.520 MHz B3 provides restricted service signals only.

GNSS-Book-Cover-Second-Edition