基于IGS超快星历预报卫星钟差及其精度分析

在实时GPS精密单点定位中,能否快速有效地得到高精度的卫星钟差预报值是影响实时单点定位速度和精度的一个重要因素,由于GPS原子钟的高频率、高敏感和极易受到外界及其本身因素影响的性质使得卫星钟差预报至今都没能得到很好地解决,本文在目前的卫星钟差预报基础上,分别探讨了利用灰色模型理论、线性模型和二次多项式模型等方法,以IGS超快星历中2004年12月7日卫星钟差观测资料预报8日的卫星钟差为例进行卫星钟差预报研究,初步得出如下结论:在利用IGS超快星历的前一天的卫星钟差观测值预报后一天的钟差时,线性模型相对方便有效;而灰色模型只要选取合适的模型指数系数,能得到较高精度;但二次多项式模型预报精度较差。利用线性模型能达到或优于IGS超快星历预报钟差的预报精度。

Study on GFS satemte dock bias prediction with IGS ultra-rapid ephemeris

In real-time GPS precise point positioning (PPP),real-time and reliable satellite clock bias (SCB) prediction is a key to implement real time GPS.But it is difficult to hold the nuisance and inenarrable performance of space-borne GPS satellite atomic clock because of its high-frequency,sensitivity and impressionable.Baaed on the current common used methods,grey model,linear model and quadratic polynomial model were discussed and compared in this paper.Taking the observations of IGS uhra-rapid products on 7th and 8th,Dec,2004 for example,some helpful primary conclusions were obtained.It was shown that during the course of prediction SCB of current-day with the previous-day observations in IGS ultra-rapid products,linear model was superior to quadratic polynomial model,and it could attain even superior to that of IGS ultra-rapid products,grey model could also get high-precise SCB predictions as long as choosing an appropriate exponential coefficient (EC) .