Fault-Tolerant GPS/INS Navigation System with Application to Unmanned Aerial Vehicle

摘要

A fault-tolerant estimator is obtained from fusing the concept of fault detection with estimation. At the heart of the fault-tolerant estimator is a bank of discrete-time fault detection filters. The focus of each filter design is to minimize the effect of a chosen set of faults on the residual; this fault set is denoted "nuisance" and acts as a disturbance. As the disturbance attenuation bound is set to zero and the effect of the nuisance eliminated by state reduction, the transmission of the nuisance is blocked. The reduced-order discrete fault detection filter produces estimates uncorrupted by the nuisance fault. Using a residual screening method, the onset of a fault is announced and the fault identified. In a bank of fault detection filters, one filter is designed to be insensitive to the detected fault and therefore, the fault-tolerant state estimate reduces to that uncorrupted estimate. Previous voting schemes relied on statistical tests whereas the fault-tolerant estimator is based on a deterministic test on the local filter residuals. The performance of such a structure is tested on sensor faults and the quality of estimation is compared to that of a Kalman filter.