Comparison Between Adaptive Extended Kalman Filters for INS Accurate Fine Alignment Process

The fine alignment process is aimed to reduce initial attitude and inertial sensors errors before system operation. Such process is critical for the navigation solution accuracy, in particular, for situations of pure inertial navigation. In this paper, we compare different types of adaptive extended Kalman filters for a scenario of velocity aided fine alignment. Results show that a proper choice of an adaptive filter in the alignment process can greatly improve the accuracy of the navigation error-states. As a result, the time duration of the fine alignment process can be shortened.