An Improved Combination Method of Real-time Multi-system Orbit and Clock Corrections

Real-time precise satellite orbit and clock corrections play an important role in real-time precise point positioning (PPP). Due to the influence of network transmission and outliers of real-time corrections, the accuracy of user positioning is unreliable by using corrections from a single source. Thus, it is necessary to use the combination method to provide a more reliable and available corrections. In this contribution, we focus on an improved method regarding anomalous multi-system real-time satellite orbit and clock corrections. Firstly, since the orbit and clock corrections are self-consistent, a more general model for both orbit and clock combinations is proposed based on Square Root Information Filter (SRIF). Secondly, considering a proper clock model will enhance the accuracy of clock combination, one-order and two-order polynomial clock models are used for satellite clock combination. To validate the method, an experiment with 8 real-time satellite orbit and clock products is employed. Compared to all raw corrections, the combined corrections show the best performance for both stability and availability. Moreover, the accuracy of real-time PPP by using the combined corrections also validates the method proposed.