A Method for SINS Initial Alignment of Large Misalignment Angles Based on Simplified Sage-Husa Filter with Parameters Resetting

The SINS initial alignment with large initial misalignment angles often causes alignment failures when using the standard Kalman filter (KF). In this study, an adaptive alignment method of multi-resetting the state covariance matrix of simplified Sage-Husa adaptive filter was proposed. This method can not only raise its efficiency and adaptability, but also solve the nonlinear problems brought by large initial misalignment angles. The comparison among the proposed method, the standard KF and the standard KF with parameters resetting was conducted in the same simulating circumstances. The results indicate that, compared with the conventional alignment method, the proposed method can highly shorten the alignment time for over 50% and improve the attitude precision of large initial misalignment angles by 0.1143 degree, which can be as precise as small misalignment angles.