Real-time Precise Orbit and Clock Estimation for BDS-3 Constellation: Accuracy and Efficiency Assessment postprint

Abstract: BeiDou navigation satellite system (BDS) is an independent global navigation satellite system (GNSS) developed by China. The three-step strategy was adopted from the very beginning and the third and final step, BDS-3, had been officially announced opera#2;tional on July 31, 2020. An essential and necessary task is to generate precise orbit and clock products in real time, only in this way can BDS-3 constellation be ready for widespread use from ordinary to high-precision real-time applications. In this work, keeping accuracy and efficiency in mind, several experiments are conducted to find an adequate size of tracking networks. It is shown that, up to 60 stations, the accuracy of BDS-3 orbit and clock products can not be improved by increasing the number of tracking stations. Further accuracy im#2;provements should depend on solving some modelling defects such as lack of antenna phase center corrections and imperfection of solar radiation pressure models.