基于最优三轴姿态测定算法的舰载惯导粗对准方法

Coarse alignment method based on optimized three-axis attitude determination algorithm for shipboard SINS

针对舰载条件的捷联惯导粗对准问题,提出了一种简单可行的最优粗对准方法。根据双矢量定姿的原理,分别将两个观测矢量之一作为基准,通过两次三轴姿态测定算法得到两个姿态矩阵,然后根据观测矢量的方差特性加权得到精度最优的姿态阵。阐述了三轴姿态测定算法的基本原理,分析了最优三轴姿态测定算法与基于高斯马尔科夫估计的三轴姿态测定算法的统一性,解析了基于最优三轴姿态测定算法的舰载惯导系统粗对准方案,并对传统三轴姿态测定算法和最优三轴姿态测定算法进行了应用比较。蒙特卡洛50个样本的仿真结果表明,采用最优三轴姿态测定算法明显优于传统三轴姿态测定算法,可使得东向、北向和天向姿态误差角均值分别为4.78,9.21和0.29,标准差分别为0.11,0.07和1.08,水平失准角最大值9.37,方位失准角最大值2.8,能够有效确定出载体的粗略姿态,在此基础上能更好实现该状态下的舰载惯导精对准。

A simple and feasible optimized coarse alignment method is introduced to solve the problems of coarse alignment for shipboard SINS on swing base. According to double-vector attitude determination theory, the direction cosine matrix between two coordinates can be determined by two unparallel vectors, and the two matrices can be generated by three-axis attitude determination （TRIAD） when processing one measured vector first and then when processing the other measured vector first. The optimized attitude matrix can be acquired by weighted vector-sum of observation vectors based on their variance characteristics. The basic principle of attitude determination for TRIAD is put into a nutshell. The optimized TRIAD and TRIAD algorithm based on Gauss-Markov estimation is discussed. The coarse alignment method of shipboard SINS based on optimized TRIAD is analysed and compared with TRIAD algorithm. The monte-carlo simulations with 50 sample show that the mean values of misalignment angle along east, north and upside direction are -4.78？, 9.21？and 0.29° respectively, and the standard deviations are 0.11？, 0.07？ and 1.08°, respectively. The Max. of level misalignment angle and azimuth misalignment angle are 9.37？ and 2.8°, respectively. The coarse alignment based on optimized TRIAD can determine rough attitude and guarantee the accurate alignment of SINS.