EM算法在卫星轨道计算中的应用  

Application of the EM Algorithm in the Calculation of Satellite Orbits

作　　者：杜琨[1] 宋迎春[1] 肖琴琴[1] 

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《全球定位系统》2013年第2期41-44,共4页Gnss World of China

基　　金：国家自然科学基金(批准号:40874005)

摘　　要：利用精密星历文件计算卫星轨道坐标,现今较常用的方法是拉格朗日插值法和切比雪夫拟合法。在实际应用中,8阶拉格朗日内插或者12阶切比雪夫拟合即可达到厘米级精度。然而,IGS精密星历文件经常会受到卫星信号限制等原因导致部分数据失真或缺失。在数据缺失或数据量较少的情况下,无法采用高阶的插值法或拟合法。只能降阶对其插值或拟合,从而导致计算精度降低。采用EM算法,添加与卫星轨道信息相关的"潜在数据",可以有效解决这一问题,大大提高卫星拟合的精度。Currently, the commonly used methods to calculate the satellite orbit coordinates by using the precise ephemeris file are Lagrange interpolation and Chebyshev fitted equation. In practical applications, either 8th-order Lagrange interpolation or 12th-order Chebyshev fitted equation can achieve centimeter-level precision. However, the IGS precise ephemeris files often result in data distortion or data missing because of satellite signal constraints and other reasons. Higher order interpolation and fitting can not be used when data is missing or the amount of data is small. In this case, we can only reduce order to interpolate or fit, resulting in lower computational accuracy. Using EM algorithm to add potential data related to satellite orbit information, can effectively solve this problem, and greatly improve the fitting accuracy of the satellite.

关 键 词：精密星历 插值法 拟合法 缺失数据 EM算法 

分 类 号：P228.4[天文地球—大地测量学与测量工程]