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...