测站数目及分布对地球自转参数解算精度的影响

The effect of station numbers and distribution balance on earth rotation parameters with GPS observation

为研究GPS数据解算地球自转参数(ERP)精度受测站数目及分布均衡性影响规律的问题,该文利用全球国际GNSS服务(IGS)站提供的GPS数据,设置不同测站数、不同测站分布均衡程度的解算策略,通过对比不同策略下ERP解算精度,来研究测站数目和均衡程度对ERP解算过程中的影响规律。结果表明,考虑到解算效率的情况下,测站数目选择40个时能达到最佳效果,此时极移在x方向的RMS值为0.223 081 mas,在y方向的RMS值为0.186 941 mas;对于测站分布均衡性,该文提出用观测网的网重心坐标转换为大地坐标作为评价指标,当网重心越接近地心,解算精度越高。研究成果表明在利用GPS数据解算ERP参数时,选择适当数目的测站以及分布均衡性好的解算策略可以提高解算效率及精度。

In order to study the influence of GPS data on the accuracy of calculating the earth rotation parameters(ERP) by the number of stations and the distribution balance,this paper used the GPS data provided by the global International GNSS Service(IGS) stations to set up different strategies for calculating the number of stations and the distribution balance degree of stations. By comparing the ERP calculation accuracy under different strategies,the influence of the number and balance degree of stations on the ERP calculation process was studied. The results showed that the best result could be achieved when the number of stations was 40,when the RMS value of polar shift in x direction was 0.223 081 mas and that of y direction was 0.186 941 mas. For the balanced distribution of stations,this paper proposed that the coordinate of gravity center of observation network be transformed into geodetic coordinate as evaluation index,and the closer the gravity center of network is to geocentric,the higher the accuracy of calculation. The research results show that when using GPS data to solve ERP parameters,choosing a proper number of stations and a well-distributed balanced solution strategy can improve the efficiency and accuracy of the solution.