A Two-Fault Detection and Elimination Approach to the Receiver Autonomous Integrity Monitoring

Abstract The Receiver Autonomous Integrity Monitoring (RAIM) technique is very important for the GNSS receiver to detect faulty measurement sources before they mislead the positioning solution. Based on the parity RAIM method, a simple algorithm to detect and eliminate one fault is provided. However, there is no such a simple algorithm to detect and eliminate two faults. A general approach is traversing all possible fault cases and calculate the sum of the squares of the residual errors (SSE) of each case by solving the observation equation. However, solving the observation equation takes a lot of computation. This paper proposes a detection and elimination algorithm that can deal with no more than 2 faults, based on the least-squares-residual method. The new algorithm avoids solving the observation equation for each possible fault cases, and has very low computational complexity. Simulations are done to evaluate the performance of the algorithm, and the effect of the satellite geometry conditions on the algorithm is also discussed.