Research On Underwater Integrated Navigation System Based On FOG Sins

It is the high precision and stability that is the key of AUV successfully completing underwater tasks. However, single navigation mode for its defects limits AUV effectively working. The underwater integrated navigation system, which consists of strap-down inertial navigation sysem (SINS), Doppler Velocity Log (DVL), Magnetic Compass (MCP) and Depth-gauge (Depth), fully utilizes multiple navigation information to aid SINS, with the advantage of high precision and strong robustness. The paper mainly includes five aspects as follows.(1) The navigation principle of SINS, DVL, MCP and Depth and information fusion theory, including Kalman filtering and federal Kalman filtering are elaborated(2) The error source of navigation systems and the corresponding mathematical model are studied. Meanwhile, the state equation and measurement equation of SINS/DVL, SINS/MCP, and SINS/Depth are built, and the underwater integrated navigation system is structured based on federal Kalman filtering theory.(3) Aimed at the fault diagnosis of the underwater integrated navigation system, a kind of improved X detecting of residual is proposed, which adjusts the structure of the traditional X detecting of residual and introduces the mean and standard deviation of residual as criterion, and realizes quickly detecting and identifying system fault.(4) Aimed at the SINS initial alignment problem under the complex environment, a new method using the extern velocity and the motion restraining of turning maneuver is proposed to improve the observability of azimuth misalignment angle and the error of IMU, and realizes the SINS initial alignment under the maneuvering environment.(5) Aimed at the underwater integrated navigation algorithm and the in-motion alignment algorithm, a lot of simulation experiments are conducted. The results show that the underwater integrated navigation system can maintain high precision and strong robustness in multiple maneuvering environments. Through prototype test including turntable test and on-board test, the reliability of the underwater integrated navigation system based on WINDOWS+RTX and the effectiveness of above-mentioned algorithm are further verified.