An intelligent fault-tolerant strategy for AUV integrated navigation systems

To ensure the security and reliability of the autonomous underwater vehicle (AUV), an intelligent fault-tolerant strategy for integrated navigation systems is presented in this paper. The improved federated Kalman filter (FKF) is designed to fuse the multiple subsystems, including strapdown inertial navigation system (SINS), magnetic compass (MCP), Doppler velocity log (DVL) and terrain aided navigation (TAN). The intelligent fault-tolerant structure of SINS/MCP/DVL/TAN integrated navigation system is first established, which includes adaptive local filters and fault isolation decision (FID) modules. Fuzzy logic is introduced to adaptively adjust the measurement covariance matrixes of local filters online. FID module is implemented based on fuzzy reasoning. The simulation results show that, the proposed fault-tolerant strategy detects and insulates the faults effectively, which can greatly improve the reliability and guarantee the safety of AUVs in complex underwater environments.