Fault exclusion method for ARAIM based on tight GNSS/INS integration to achieve CAT-I approach

Advanced Receiver Autonomous Integrity Monitoring (ARAIM) with two or more constellations will be widely used in the aircraft to safeguard the safety of the flight crew and passengers. The ARAIM based on tight integration of Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) attracts widespread attention for its ability to meet the integrity requirement of Category-I (CAT-I) approach. However, more available satellites lead to higher satellite fault probability. So a fault exclusion (FE) method is necessary to continue providing positioning services and integrity performance after the faults are detected. In this study, an FE method for GNSS/INS ARAIM is presented to identify the failing satellite and to provide real-time integrity performance after exclusion. The proposed subset-identifying method takes into account the prior probabilities of satellite faults, which is able to greatly improve the accuracy of finding the failing satellite. The simulation results show that the proposed after-exclusion integrity estimating method is able to provide integrity performance meeting the requirements of CAT-I. Therefore, the proposed method is able to improve the continuity and availability performance of the navigation system for civil aviation.