Adaptive interactive multiple model and its application in INS/CNS integrated navigation system

According to the problem that the measured noise statistical characteristics differ with the change of application enviroment in inertial/celestial (INS/CNS) navigation system and the filter accuracy was decreased, an adaptive interactive multiple model (AIMM) algorithm was presented. The AIMM algorithm which combined the IMM algorithm with the improved Sage-Husa adaptive filtering algorithm can achieve the coverage of real situation well through few sub-models. The simulation results demonstrate that the algorithm can cover the change of the real situation better than the conventional Kalman filter. Stronger adaptive ability of navigation filter can be obtained by the adaptive algorithm when the observation was abnormal. The errors of navigation parameters have no significant change when observed noise statistical characteristics changed singularly. The navigation filter has a certain adaptive ability when the observations change. So the algorithm can ensure that the navigation filter operates reliably, and the accuracy and reliability of integrated navigation system are improved as well.