A new cascade method for detecting GPS multiple outliers based on total residuals of observation equations

A technology of Receiver Autonomous Integrity Monitoring (RAIM) is developed to detect faults with redundant Global Position System (GPS) pseudorange measurements. Conventional RAIMs use only the residuals of the least square algorithm and can detect the single outlier with high probability, but they fail frequently to detect the multiple outliers correctly. This article develops a new cascade method to detect GPS multiple outliers. In the method, multiple outliers will be detected with several outlier searching steps. In the every step, LSM total residuals will be estimated after lowering of weight in wrong observations. The numerical results proved the effectiveness of the proposed cascade method.