未知纬度条件下基于空间圆拟合的SINS初始对准方法

SINS Initial Alignment Method Based on Space Circle Fitting Without Latitude

关键词:  初始对准  最小二乘法  凝固载体坐标系  空间圆拟合  低通滤波

Key words:  Initial alignment  Least squares method  Solidified carrier coordinate system  Spatial circle fitting  Low pass filter

摘要:

传统的捷联惯导系统(SINS）晃动基座初始对准算法，如积分双矢量方法和多矢量Wahba方法等均需要精确的纬度信息，粗对准偏航角误差较大。针对此特点，提出了一种未知纬度条件下基于空间圆拟合的SINS初始对准方法。根据重力矢量在惯性系中绕地轴旋转包含北向信息的特征，以初始时刻凝固载体坐标系作为惯性系，首先对重力矢量在凝固载体系内进行投影并滤波，对其矢量端点进行空间圆拟合，然后通过三角几何关系得到导航坐标系，从而完成对准过程。通过仿真验证，证实了该对准方法不需要已知对准点的精确位置信息，相比于积分双矢量方法与多矢量Wahba方法，偏航角对准精度分别提高了12.37′与5.10′。

Abstract:

As the traditional initial alignment algorithms with swaying base of strapdown inertial navigation system(SINS),such as the integral double vector method and the multi-vector Wahba method, need accurate latitude information and have large coarse alignment error, a SINS initial alignment method based on spatial circle fitting without latitude is proposed. According to the fact that the information of north is included in the gravity vector's rotating about the earth's axis in the inertial frame, the gravity vector is firstly projected and filtered in the solidification carrier frame which is taken as inertial frame, and the spatial circle fitting is performed with vector ends, then the navigation frame is obtained through triangular geometric relationship, and finally the alignment process is completed. The simulation results verify that there is no need to provide the precise position information of the alignment point to the proposed alignment method, and compared with the integral double vector method and the multi-vector Wahba method, the yaw angle alignment accuracies are improved by 12.37′ and 5.10′ respectively.