progress, contribution and challenges of compass/beidou satellite navigation system

Satellite navigation has stepped into the era of a hundred flowers in bloom. The progress, application, con-tribution and challenges of Compass/Beidou satellite system is reviewed and analyzed. Firstly, the construction prin-ciples and development steps are introduced. Secondly, the general realizations of signal frequency and the coordi-nate system as well as the time system of Beidou satellite navigation system in the frame of compatibility and interop-erability are described. Thirdly, in the concept of redundancy, the main contributions of Beidou system are analyzed. At last, the applications and the main challenges of Beidou system are reviewed.