GPS卫星精密星历的轨道插值

Orbital Interpolation of GPS Satellite Precise Ephemeris

IGS只提供采样率为15 min的精密星历,而在卫星精密导航、定位等计算中需要更高采样率的轨道位置,因此需要通过轨道插值的方法对精密星历进行加密。以1 d间隔30 s的插值数据为基础,分别使用常规算法和滑动算法对轨道插值常用的拉格朗日插值和切比雪夫插值进行分析,可为卫星轨道插值计算时选取插值方法、阶次提供理论依据。结果表明,利用常规算法计算,两种插值的最佳精度均能达到mm级;利用滑动算法计算,两种插值的最佳精度均能达到亚mm级;相同条件下滑动算法的精度优于常规算法,滑动算法的计算结果比常规算法更稳定,且对龙格现象有抵抗力。

IGS only provides precise ephemeris with 15 minutes sampling rate,but it requires a higher sampling rate orbit position in the calculation of satellite precise navigation and positioning.Therefore,the precise ephemeris needs to dispose by orbit interpolation.Based on the interpolation data of every interval of 30 seconds of the day,this paper used the conventional algorithm and the sliding algorithm to analysis the Lagrangian interpolation and Chebyshev interpolation,which were commonly used for orbital interpolation.The results show that the best accuracy of the two interpolations can reach the millimeter level by the conventional algorithm,and the best precision of the two interpolations can reach the sub-millimeter level by the sliding algorithm.The accuracy of the sliding algorithm is better than the conventional algorithm.The sliding algorithm is more stable than the conventional algorithm,and is resistant to the Runge phenomenon under the same condition.This study can provide theoretical basis for the selection of interpolation method and order in satellite orbital interpolation calculation.