基于选星算法的GPS载体姿态测量系统研究

Research on GPS attitude system based on select satellite algorithm

传统的GPS载体姿态测量算法是利用全部可见卫星的测量信息进行姿态计算的,针对这一情况提出将选星算法应用于姿态测量过程的改进算法。首先依据参数的约束条件,确定选星数目为5,在解算方程组中,存在GDOP值随方向余弦矩阵的行列式绝对值的增大而总体趋势减小的关系,记录下能使方向余弦矩阵行列式绝对值最大的5组卫星组的行列式绝对值及其卫星标号,分别计算这5组卫星组的GDOP的值,GDOP值最小的即为选星结果。MATLAB仿真结果表明,改进的算法虽然在基线解算的精度上降低了一个数量级,基线误差由毫米级降低到厘米级,但是姿态角的解算精度与原算法相当,并且在程序运行时间方面提高了将近一倍。在工程应用中,对于载体的姿态解算在时间代价方面要求较高,因此,改进的算法有一定的优越性。

The traditional GPS attitude determination algorithm is based on the information of all visible satellites. The select satellite algorithm is taken in the attitude determination algorithm in this paper. The select satellite number is 5 based on the number of equations must be greater than the number of unknown parameters. 5 satellite groups with the most absolute value of determinant are recorded according to the relationship of GDOP and the absolute value of determinant of the direction cosine. The satellite group with the minimum value of GDOP is used to determine attitude. The simulation results show that although the improved algorithm reduced by an order of magnitude in the accuracy of the baseline solution, the attitude angles solver accuracy with the original algorithm is quite. The improved algorithm is better in the program＇s run time. The require is higher for the time consuming in engineering applications. Therefore, the improved algorithm is better.