State-Domain-Based Integrity Monitoring of Satellite Orbit and Clock Corrections for RT-PPP

Real-time precise point positioning (RT-PPP) relies on real-time service (RTS) as satellite orbit and clock corrections for users to achieve decimeter or centimeter-level positioning. Although the RTS is nearly always with high accuracy, it will inevitably have abnormal values or accuracy degradation. The faults from satellite orbit and clock corrections must be detected to provide a reliable positioning performance. In this contribution, a state-domain-based integrity monitoring method of satellite orbit and clock corrections for RT-PPP is proposed. The prediction models for satellite orbit and clock correction parameters are constructed by analyzing the daily variation statistical characteristics of correction parameters in the state domain. After compensation for nonideal error distribution by overbounding, the detection statistics and minimum detection errors are established based on the corrected precision satellite orbit and clock comprehensive errors, which aim to monitor the quality of satellite corrections. The experiment is used to test the false alarm and missed detection performance of the proposed method. The results confirm that the abnormal satellite orbit and clock corrections can be detected accurately with a given missed detection rate of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 10^{-{3}}$ </tex-math></inline-formula> and false alarm rate of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 10^{-{5}}$ </tex-math></inline-formula>. Moreover, using the proposed monitoring method, the RT-PPP results after excluding abnormal satellite orbit and clock corrections can be improved by an average of 6.51%, 13.94%, and 8.14% in the east, north, and up directions, respectively.