海洋重力辅助导航系统的系泊对准算法

Mooring alignment algorithm for marine gravity aided navigation system

捷联惯导系统在系泊条件下的初始对准是海洋重力辅助导航实用化的关键问题之一,本质上属于三轴姿态确定问题。基于惯性凝固假设,构建了船载捷联惯导系泊对准模型,研究了传统三轴姿态确定双矢量算法。对双矢量算法进行改进,提出了一种基于加权矢量和三轴姿态确定的系泊对准算法,该算法利用两个观测矢量的误差标准差构建加权系数,生成了精度更高的基准矢量,从而提高系泊对准的精度,并且该算法只需进行一次三轴姿态解算,保持了计算量小、耗时短的特点。数值仿真和船载试验结果表明,改进后的系泊对准算法在保证初始对准快速性的前提下有效提高了对准精度,两个水平姿态角误差小于4′,航向角误差在10′左右,满足海洋重力辅助导航系统的应用需求。

The initial alignment of SINS in mooring conditions is a key problem to the practicability of marine gravity aided navigation system, which is essentially a three-axis attitude determination（TRIAD） problem. This paper built up a shipboard SINS mooring alignment model based on inertial freezing hypothesis, and improved the two-vector attitude determination algorithm based on the study of traditional one, which is an mooring alignment algorithm based on weighted vector and TRIAD. In the new algorithm, the standard deviation of two observation vectors is utilized to construct the weighting coefficients and generate a higher precision reference vector. Thereby, the accuracy of mooring alignment is improved. The algorithm requires just one times of TRIAD calculation, so the system keeps the advantages of small computation amount and short time-consuming. Numerical simulation and shipboard experiment results show that the weighted vector TRIAD algorithm effectively improves the alignment accuracy without decreasing the rapidity of the initial alignment. The horizontal attitude error is less than 4′, and the heading angle error is about 10′, which meet the application requirements of marine gravity aided navigation system.