GPS卫星星历对测站及基线精度的影响

The effects of GPS satellite ephemeredes on the GPS monitoring stations and baseline precision

关键词:  广播星历  精密星历  基线  精度

Key words:  broadcast ephemeris  precise ephemeris  baseline  accuracy

摘要:

通过采用高精度的数据处理软件gamit/globk对观测数据的认真分析处理,对比广播星历与精密星历对测站LC相位残差的影响,认为在相同条件下同一测站相同时间的广播星历轨道误差比采用精密星历时要大1.5~27.2mm,这一差值与测站含有短基线数目及短基线的长度有一定的关系;同时通过采用双频差分技术处理数据后,对于长度在300km以内的基线,采用广播星历时的基线误差在5~8mm之间,采用精密星历时基线误差在3.2~6.8mm之间,基线误差互差在1.2~1.8mm之间。通过实例分析后认为基线长度在300km范围内广播星历与精密星历具有相当的解算效果。较前人^[1~6]提出的100km适用基线长度大幅度提高,究其原因主要是选用了高精度的数据处理分析软件,同时采用了较高精度的初始坐标、合适的约束条件、观测数据有效组合和各项误差改正模型。

Abstract:

The present paper focuses on the analysis and processing of the observational data by using the highprecision processing software gamit/globk, and the contrast of the effects of broadcast ephemeris and precise ephemeris on the LC phase residuals of GPS monitoring stations. Under the same conditions, the orbital errors by using the broadcast ephemeris tend to be 1.5 to 27.2 mm greater than those by using the precise ephemeris. These differences have something to do with the number and length of the short baselines in the stations. Through the data processing by using the dual-frequency differential analysis, for the baselines with the length of 300 km or less, the baseline errors generally range between 5 and 8 mm as using the broadcast ephemeris while the baseline errors vary from 3.2 to 6.8 mm as using the precise ephemeris; the differences of the baseline errors range between 1.2 and 1.8 mm. It can be seen from the algorithm case study in the text that both the broadcast ephemeris and precise ephemeris are well solvable when the baselines lengths come up to 300 km or less, which have increased by a big margin than the baseline length of 100 km proposed by the previous research workers. The authors in this study owe all the progress to the application of the high-precision software gamit/globk and initial coordinates, suitable constracts, effective use of the observational data and processing models.