A Novel Integrity Monitoring Method of Ultra-Tightly Integrated GNSS/INS Navigation System

Conventional Receiver Autonomous Integrity Monitoring (RAIM) has limitations that the Number of Visible Satellite (NVS) for Global Navigation Satellite System (GNSS) fault detection is not less than 5 and the NVS for GNSS fault detection and exclusion is not less than 6. To avoid these limitations, a novel integrity monitoring method of ultra-tightly integrated GNSS/INS navigation system is proposed in this paper to monitor GNSS faults and determine the faulty satellite. This method can detect step pseudo range errors and slowly growing pseudo range errors and exclude the faulty satellite from the ultra-tightly integrated navigation system. To test the integrity monitoring method, an experiment platform is built based on a GNSS signal simulator and some simulations are done in the high dynamic scenarios including the step error and slowly growing errors. The experiment results verify that the proposed method can achieve the detection and exclusion of GNSS faults without any NVS limitation.