Improved RAIM algorithm for identifying simultaneous two-faulty satellites based on faulty feature plane

Traditionally, the receiver autonomous integrity monitoring (RAIM) algorithm such as parity vector method for identifying two-faulty satellites based on identification threshold led to not only higher missed detection rate but also higher false alarm rate and fault counteraction, which decreased the correct identifying ratio. Therefore, an improved RAIM algorithm was proposed. On the basis of parity vector method, the improved algorithm constructed a faulty feature plane, and faulty satellites were identified by the geometry relationships between the plane and the proposed parity vector. These made the algorithm immune to the problem of high identifying threshold and improved the identifying ratio. Semi-physical simulation results indicated that the correct identifying ratio of the proposed algorithm reached 90%, and the performance was improved compared with the traditional algorithm.