GPS广播星历的拟合与拟合历元数的影响分析

The Influence Analysis of GPS Broadcast Ephemeris Fitting and Fitting Epoch Number

摘要: 导航卫星的广播星历拟合是卫星导航系统中一个重要的技术环节，影响到用户的定位精度。本文推导了星历参数的拟合算法，并且通过算例得到了较高精度的参数拟合结果。参数的拟合结果中大数量级的拟合参数达到了1.0e+06及以上的拟合精度，小量级的参数拟合精度受到计算机浮点数的精度影响较大，有待进一步提高。文中分析了不同拟合历元数对参数拟合结果的影响，通过探测突变的拟合历元，有助于寻找最佳的拟合时长。

Abstract: Broadcast ephemeris fitting of navigation satellites is an important technical aspect in the satellite navigation system that affects the user’s location accuracy. Ephemeris parameters fitting algorithm is derived, and the higher precision of parameter fitting with examples is obtained. Fitting arguments of large magnitude in parameters fitting result achieve the fitting accuracy of 1.0e+06 and above, and minor-level parameter fitting precision greater affected by computer floating- point precision needs to be further improved. This paper analyzes the different fitting epoch number effects on the results of parameter fitting, by detecting mutation of fitting epoch, helpful to find the best fitting duration.