The beidou navigation system is dedicated to providing high-quality positioning, navigation and timing services to global users, including both open and authorized services. The open service is a location, speed and timing service that is provided free of charge globally, with a positioning accuracy of 10 metres, a speed accuracy of 0. 2 metres/s and a time accuracy of 10 ns. The mandated service is to provide positioning, speed measurement, timing and communication services and system integrity information for users with high-precision, high-reliability satellite navigation needs. The beidou navigation is no less accurate than that of europe and america, and the beidou satellite navigation system solves the question of who, when and where, and this is the beidou feature service, and you can walk through the world with a beidou terminal. Beidou (compass) navigation satellite system is an autonomous, independently operated global satellite navigation system being implemented by china. The goals of the system-building are to establish an autonomous, open-compatible, technologically advanced and stable global beidou satellite navigation system, to facilitate the formation of a satellite navigation industry chain, to develop a sound system of support, promotion and support for satellite navigation applications, and to promote the wide application of satellite navigation in all sectors of national economy and society. The beidou navigation system consists of three components, the space segment consisting of five geostationary and 30 non-geostationary satellites, the ground segment comprising several earth stations such as the master control station, the injection station and the monitoring station, the user segment comprising the beidou user terminal and terminals compatible with other satellite navigation systems. Beidou navigation is an important spatial information infrastructure. China attaches great importance to the construction of satellite navigation systems and has been working to explore and develop satellite navigation systems with autonomous intellectual property rights. In 2000, the beidou pilot navigation system was first completed, making my country the third country in the world to have an autonomous satellite navigation system after the united states and russia. The system has been successfully applied in areas such as mapping, telecommunications, water, fisheries, transport, forest fire prevention, disaster mitigation and response and public safety, with significant economic and social benefits. In particular, it played an important role in the 2008 beijing olympic games and the wenchuan earthquake response. In order to better serve construction and development and to meet global application needs, we have initiated the construction of the beidou satellite navigation system. Beidou navigation better serves the world, enhances compatibility and interoperability between beidou satellite navigation systems and other satellite navigation systems, and promotes the full application of satellite positioning, navigation and timing services. China is ready to cooperate with others in developing satellite navigation。