A Framework of Cubature-Hᵢ/H∞ -Fault Detection and Robust H-Infinity Kalman Filter of Ship SINS/GNSS Integrated System

xThis article deals with the problem of considering both robust fault detection and accurate state estimation for a strapdown inertial navigation system and global navigation satellite system (SINS/GNSS)-integrated navigation system for ships within a unified framework. Under the assumption that the process disturbance and measurement noise being ℓ2-norm bounded, a cubature Hi/H∞ fault detection filter (FDF) considering both sensitivity and robustness to disturbance is proposed to detect faults with a postfilter and an observer gain. However, the estimated state value of the above algorithm is theoretically a suboptimal solution. To solve this limitation, an adaptive algorithm based on the measurement residual and a scaling factor is proposed to improve the accuracy of state estimation in the proposed cubature Hi/H∞ FDF. To guarantee stability when faults are extremely large, the framework uses a robust H-infinity cubature Kalman filter. Finally, a simulation is implemented to demonstrate the effectiveness of the proposed method, considering the threshold selection for different cases.