惯导系统初始对准的非线性滤波算法

本文推导了方位误差角比较大时惯导系统初始对准的误差方程，在这个误差中包含了非 线性的部分。在方位误差角较小时，可将非线性的对准方程简化为线性的对准方程。用卡尔曼 滤波对线性系统进行仿真，用扩展卡尔曼滤波、迭代滤波、二次滤波对非线性系统仿真。比较仿 真结果可见，扩展卡尔曼滤波可大大提高方位对准的精度，而迭代滤波、二次滤波在方位角上 又比扩展卡尔曼滤波的精度高。

Nonlinear Filtering Algorithm for INS Initial Alignment

This paper derived the initial alignment error equation of an INS when the azimuth errors are considerably large,including the nonlinear part.When the azimuth error is fairly small,the nonlinear alignment equation can be simplified to a linear one. The standard Kalman filter is used to simulate the linear system.The extended Kalman filter,the iteration filter and the secondary filter are used to simulate the nonlinear system.The simulation results show that the extended Kalman filter greatly improves the accuracy of azimuth alignment.However,the accuracy of the ireration filter and the secondary filter for the azimuth estimate is even better.