The error compensation design for transfer alignment

In this paper, three error compensation methods are devised to reduce the alignment errors induced by lever arm, body flexure, and measurement time delay respectively. A linear error model based on velocity and attitude is constructed for transfer alignment. Then, due to obviously different frequency distribution between disturbed acceleration produced by lever-arm effect and body itself acceleration, the Butterworth lowpass filter is designed to eliminate such influence. Moreover, with respect to the body flexure and time delay, Kalman filter is properly designed to restrain the effects by augmenting the flexure state and delay state into the conventional linear state equations. Specifically in flexure compensation, the two different transfer alignment modes as velocity and attitude matching algorithm and velocity and angular rate matching algorithm are compared to illuminate their performances. The simulation results show that the proposed methods are effective enough resulting in considerably less azimuth alignment errors.