Real‐time BDS signal‐in‐space anomaly detection method considering receiver anomalies

Abstract

Signal-in-space user range error (SIS URE) can reach tens of meters or even tens of thousands of meters, and this may introduce hazardous misleading information (HMI) to real-time navigation and positioning. Monitoring of real-time SIS anomalies could improve the reliability of navigation and location services for end-users. For BeiDou satellites, the user range accuracy (URA) index currently broadcasted by navigation ephemeris does not reflect the true variation of URE. The anomaly detection method employed uses priori information from precise ephemerides, remains difficult for real-time detection. Additionally, the existing SIS anomalies detection method for BeiDou satellites does not exclude the influence of receiver anomalies. To address these problems, a method for calculating the instantaneous URE (IURE) was developed, and the empirical threshold was obtained by statistically analysing IURE before detecting SIS anomalies. Data of 14 stations from the Multi-GNSS Experiment (MGEX) and the international GNSS Monitoring & Assessment System (iGMAS) in the Asia-Pacific region were selected for detecting anomalies. Results were analysed in combination with the broadcast ephemeris health status indicator and the precise ephemeris detection results to verify the effectiveness of the method. It shows that the proposed method can accurately detect the starting and ending times of SIS anomalies.