Sequential probability ratio test based fault detection method for actuators in GNC system

This paper proposes a fault diagnosis method of satellite actuator based on parameters sequential probability ratio test. Sequential probability ratio test is a hypothesis test based on statistical learning, whose greatest advantages is that it does not need to prescribed the number of observed sample group, but compare each hypothesis test data to the set threshold value. Firstly, give the hypothesis testing and drawn threshold based on the given false alarm rate and missed alarm rate. Secondly, extract the characteristic parameters of the signal to be inspected, Finally, calculate the likelihood values and compare to threshold value, so that we can judge whether there is a fault signal. This article made verification experiment based on actuator fault detection of Autonomous GNC system of deep space probes, as can be seen from the simulation results, sequential probability ratio detection method can made a real-time detection of the fault signal. Compared with the fault diagnosis method based on state observer, this method reduces the average inspection time of the fault greatly.