Fault Detection and Isolation Using Satellite Geometry in RAIM

A new test statistic considering satellite geometry information is proposed for fault isolation in the GPS Receiver Autonomous Integrity Monitoring (RAIM). Conventional snapshot methods in the GPS applications have same probability of the fault detection but they have different probability of the fault isolation. We propose a new test statistic considering satellite geometry to increase the probability of correct fault-isolation. The method of fault isolation using proposed test statistic is composed of two parts that is conventional process and backup process. The proposed method is evaluated by simulation and shows that it can have higher probability of correct fault-isolation compared with conventional method especially when the Dilution of Precision (DOP) factors of two candidate measurement subsets using user-to-satellite geometry have relatively different value.