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Fault detection and diagnosis in the INS/GPS navigation system

This paper proposed a new fault detection and diagnosis (FDD) scheme based on INS (inertial navigation system) /GPS integrated navigation system. Once a fault is detected in the process of fault diagnosis, we should complete two diagnosis phases: primary diagnosis and diagnosis and isolation phase. In the primary diagnosis phase, we use filter to generate residuals that we need, then complete the fault detect based on chi-square test of residuals; In the isolation phase, we design a multiple hypothesis test for innovation sequence of the navigation system, then complete fault isolation based on generalized likelihood ratio(GLR) test. This scheme can reduce the difficulty and complexity of fault diagnosis, improve the diagnosis accuracy, and can identify the concurrent fault, strengthen anti interference ability. In addition, even if only one navigation device (INS or GPS) works properly, this scheme can still guarantee system to achieve a sufficiently accurate state estimation.