The construction of the BeiDou system was divided into three stages. At the end of 2000, the BDS-1 system was built to provide services to China. At the end of 2012, the BDS-2 system was built to provide services to the Asia-Pacific region, and around 2020, the BDS-3 system will be built to provide services to the world.
The BDS is mainly comprised of three segments: space segment, ground segment and user segment.
The BDS space segment is a hybrid navigation constellation consisting of GEO, IGSO and MEO satellites.
The basic constellation of BDS-2 is 5GEO+5IGSO+4MEO.
BDS-3 is composed of 3GEO+3IGSO+24MEO constellation, which has communication capability between satellites and satellites, and can operate independently without ground station support.
The BDS ground segment consists of various ground stations, including master control stations, time synchronization/uplink stations, and monitoring stations.
The BDS user segment consists of various kinds of BDS terminals, chips, modules and antennae, as well as application systems and application services.