Research On The Integrated Navigation System Of COMPASS/INS/TAN

Any single navigation sensor is hard to meet various military aircrafts’navigation requirements in the modern land and sky integrated war system, so integrated navigation system comes into being. In the real battlefield environment, the aircraft need to take low air raid on the enemy in order to master the battlefield initiative, but this needs to pass through complex electromagnetic area and to fully use the battlefield terrain. China doesn’t have intellectual property on GPS, so I choose Chinese COMPASS Navigation Satellite System. Therefore, the paper mainly researches the integrated navigation system of COMPASS/INS/TAN and uses federated filtering scheme to realize. The paper’s main contributions are listed as follows.Firstly, the characteristics and development of Inertial Navigation System, Global Navigation Satellite System and Terrain Aided Navigation System are systematically introduced in the thesis, including the current research status and future developing trend. After introducing the linear systems’ Kalman filtering, the characteristics of Extended Kalman Filtering and Unscented Kalman Filtering are analyzed for nonlinear systems. The EKF algorithm needs to linearize the nonlinear model, while the UKF algorithm doesn’t need linearization. The above work lays a theoretical foundation for coping with optimal navigation parameters estimation of integrated navigation system.Secondly, COMPASS Navigation Satellite System positioning principle is analyzed and the nonlinear mathematical model of the COMPASS/INS integrated navigation system with pseudo range and pseudo range rate tightly-coupled mode is built. For the nonlinear measurement equation, filters based on EKF and UKF are differently designed to estimate navigation arguments. The latter uses extended symmetric sampled scheme to get determinate Sigma sampled points, which are used to approximate the nonlinear model’s probability density distribution. After simulation and comparison, the results prove that the COMPASS/INS integrated navigation system’s navigation precision of UKF method is better than EKF method. Furthermore, the INS/TAN integrated navigation system’s nonlinear mathematical model is built based on the Sandia Terrain Aided Navigation algorithm, and the integrated navigation filter designed on EKF method is proved to improve the navigation precision.Thirdly, the optimality of the global state estimator and variance is proved for the federated filter. The chapter puts forward the COMPASS/INS/TAN integrated navigation application scheme based on federated filtering idea. And the Federated UKF is designed to make the two local filter outputs (states estimate and variances) estimate the global sate estimator and variance. After that, the above design scheme is simulated and analyzed. The global3-dimension position error and velocity error are compared with the two local filters’ corresponding3-dimension position and velocity. And the results show that the federated filtering can effectively improve the system’s navigation precision and reliability.Finally, the conclusion is given and some problems about next stage are also discussed.