Moving base alignment for SINS based on pseudo inertial navigation system modeling

Abstract

The heading error with the traditional inertial navigation system (INS) modeling is proportional to both linear movement errors and tangent function of latitude. As a result, due to the poor observability of the heading misalignment angle, the performance of initial alignment with the traditional alignment model would be influenced in non-equatorial regions, thereby leading to the filter's divergence. Aiming at this problem, an innovative INS modeling (namely, pseudo INS modeling) is proposed to implement the moving base alignment for strapdown INS (SINS). With the proposed INS modeling, the alignment model would be always equivalent to the traditional one in equatorial regions, thereby removing the influence of INS modeling on dynamic alignment and then improving the stability of alignment system of non-equatorial regions. Finally, the moving base alignment simulations assisted by Kalman filter (KF) are carried out to demonstrate the performance of the proposed method.