The Chinese navigation satellite system Beidou, also known as the Compass Navigation Satellite System, is expected to provide global service by 2020, according to the system's chief designer Sun Jiadong.
Compass will provide a free service for civilian users with positioning accuracy of within 10 metres, velocity accuracy of within 0.2 m/s and timing accuracy of within 50 nanoseconds, and a licensed service with higher accuracy for authorised and military users only.
From 2000 to 2003, China established a trial system composed of three satellites, which made it the third country to own an independent satellite navigation system. The system has now entered the launch and network arrangement stage and is expected to include full coverage of China and its surrounding areas this year. At the completion of the third stage, around 2020, Compass will be able to provide coverage of the entire world.
To date, China has launched three satellites in the second-generation constellation. The first generation satellites were launched between 2000 and 2007 to test the Beidou concept in space and provide limited services for China.
The completed constellation for global coverage is expected to comprise 35 Beidou satellites, including four geostationary orbit satellites at 58.75° E, 80° E, 110.5° E, and 140° E.
