基于非差模型的GPS卫星实时钟差估计精度分析

Accuracy Analysis of Real-time GPS Satellite Clock Estimation Based on Un-differenced Model

通过分析实时钟差估计的解算过程,实现了基于非差模型的GPS卫星实时钟差估计,利用区域和全球数据、最终和实时轨道分别求解实时钟差,并将其结果与IGS实时钟差产品进行对比,分析GPS卫星实时钟差产品的精度。算例表明:采用IGS最终轨道产品实时解算卫星钟差,平均钟差精度达到0.2ns;采用IGS实时轨道产品实时解算卫星钟差,平均钟差精度达到0.25ns;IGS实时钟差产品平均钟差精度达到0.2ns以内。实时估计的钟差和IGS实时钟差产品精度差异有很大一部分是由于双方采用的钟差解算策略不同造成的,IGS实时钟差产品和IGS实时轨道产品是同一软件求解得到,符合性更好,且两种实时钟差产品在精度评定时选择IGS最终钟差产品为参考,这对IGS实时钟差产品的评估也会有利。

By analyzing the solution process of real-time satellite clock estimation,a real-time solution of GPS satellite clock based on un-differenced model is constructed.The estimation of realtime clock is carried out by using regional and global data,final and real-time orbit respectively.And compared with IGS real-time clock products,the accuracy of GPS real-time clock products is analyzed.The results show that,to simulate real-time satellite clock,the accuracy of the average clock can reach 0.2 ns by using IGS final orbital product while the accuracy of the average clock can reach 0.25 ns by using IGS real-time orbit product,and the average accuracy of IGS real-time clock product can reach 0.2 ns or more.There is a large part of the difference in accuracy between realtime estimation of the clock and IGS real-time clock product due to the difference in the strategy used by the two sides.IGS real-time clock products and IGS real-time orbit products are solved using the same software,both have better compliance.In addition,when assessing accuracy of the two real-time clock products,it will be better to select the IGS final clock products for reference.