大摇摆情形的自对准方法
摘要
On the influence of some disturbances such as wind, the large amplitude motion will be caused. In these situations, for the strapdown inertial navigation system, there are the large misalignments in the initial phase, and the errors caused by misalignments can not be directly observed. However, for self-alignment, the information of these errors is very important. Since the system does not move in the swing situation, there exists a shake center whose speed is zero. If the system is a rigid body, then the attitude errors in the shake center are same as that in all of the system, and the self-alignment problem in shake center is same as that in the stationary case. Therefore, we only need to obtain the attitude errors in the shake center. Based on the principle of the lever arm effect, we provide a method to obtain the position of the shake center from the measurements of inertial measurement unit. To estimate the position of shake center, the level attitude errors are estimated at same time to reduce the model uncertainty. We also show that the alignment accuracy can be improved step by step by using the estimated parameters to compensate the system model uncertainty in the large misalignment case. Finally, some simulation results are presented to verify the method given in this paper.