Abstract: Fault detection and isolation is the key technology to realize safe and reliable operations of integrated navigation systems with the federated filtering. To solve the problems that the traditional residual Chi-square test has poor effect on the slow fault test, and that the state Chi-square test is easily affected by initial value errors, system noise and modeling errors, thereby increasingly deviating the state recursive value from the real values and further resulting in frequent isolation of the subsystems, this paper proposes a double state Chi-square test based integrated navigation system with federated filtering. In this algorithm, two state thrusters are used to reset the Kalman filter data alternately to avoid the pollution caused by the undetected fault of the state thrusters. The simulation results show that the improved algorithm can improve the sensitivity of fault detection and enhance the reliability of the integrated navigation system.

Key words: integrated navigation systems, fault detection, federated filtering, double state Chi-square tests, state thrusters