Lever arm estimation for the strap down inertial navigation system in the swing environment and its applications

In the swing environment, lever arm effect is an important factor to affect the precise of initial alignment. Since the precise information of lever arm is very difficult to be prior obtained, we propose an online estimation method based on the mechanism of lever arm effect, and analysis the influence on the estimates in different exciting situations. Furthermore, it is applied to self alignment with the large misalignment angles. By expanding the level misalignment angels to the estimated parameters, we online adjust the lever arm and level misalignment estimates, and then use these estimates to improve the additive quaternion model for precise alignment procedure, and derive satisfied alignment accuracy. Finally, some simulation results are presented to verify the conclusions given in this paper.