BDS PPP Time Transfer at NTSC

With the development of BeiDou navigation system (BDS), the high quality service of positioning, velocity and timing (PVT) is provided. In this paper, the GNSS international time comparison systems which are operated in National Time Service Center (NTSC), CAS and Chunghwa Telecommunication Laboratories (TL) are used for high quality and long distance Precise Point Positioning (PPP) time comparison study. Firstly the principle of BeiDou PPP is discussed and related algorithms are analyzed and verified. The time difference between local time and IGST is calculated by using the measured data of time keeping laboratories and the products of precise orbit and precise satellite clock from MGEX of IGS, then the time difference between NTSC and TL is calculated. The results show that STDEV of BDS PPP is less than 0.5ns, and frequency stability is in 10E-15 (1 day), the BeiDou PPP is almost same level with GPS. It is shows that the BeiDou can be used in nanosecond or sub-nanosecond level time compare, and can be used as the official method in the calculation of the international standard time in the future.