An in-coordinate interval adaptive Kalman filtering algorithm for INS/GPS/SMNS

This paper proposes an in-coordinate interval adaptive Kalman filter for INS/GPS/SMNS (Inertial Navigation System/Global Position System/Scene Matching Navigation System) integrated navigation system in which SMNS has the characteristics of randomness and in-coordinate interval when it outputs the reliable positioning information. The proposed filter sets the period of the INS parameters analysis as reference, the periods of parameters output of GPS and SMNS are adjusted to be integral multiple of the INS analysis period by interpolation or extrapolation method; The system is updated only based on INS information when the observation information don´t reach, it is updated based on all navigation information when the observation information reach; In addition, this method can overcome the drawbacks of the traditional Kalman filtering method when the system measurement noise is unknown. The proposed algorithm and the method proposed by reference [8] are applied to INS/GPS/SMNS integrated navigation system. Simulation results show that the in-coordinate interval adaptive Kalman filter outperforms the traditional Kalman filter.