GPS站坐标中的交点年周期误差研究

Study on the draconitic year errors in GPS station coordinates

随着数据处理精度的不断提高,GPS交点年周期误差对定位精度的影响已不可忽略.本文采用Lomb-Scargle周期图法对IGS首次处理和两次重新处理的GPS站坐标时间序列进行了频谱分析,研究了IGS数据处理策略的改进对GPS交点年周期误差的影响,并初步分析了其产生机制.频谱分析表明:站坐标残差的NEU方向都存在明显的基频为1.04 cpy的GPS交点年周期误差,而误差改正模型精度的提高使得两次重处理的站坐标残差中的虚假周期性误差更加明显;和第一次重处理相比,第二次重处理奇数频谱的GPS交点年周期误差明显减弱,改进的原因可能与第二次重处理中加入了地球辐射压改正有关.同时,在基于GPS/GLONASS联合解算的站坐标残差序列(CODE与ESA)中还存在与GLONASS轨道重复周期相关的约8天的误差.

The effects of GPS draconitic year errors on the accuracy of GNSS positioning cannot be neglected, with the improving precision of GNSS products. The study has been conducted on GPS station coordinate time series obtained from the first operational,first reprocessing and second reprocessing campaigns by means of the Lomb-Scargle periodogram,focusing on the effects of updated data processing methodology on GPS draconitic year errors,and preliminarily researching the mechanism about how these anomalous periodic errors are produced. Pervasive harmonic signals with a fundamental of 1. 04 cpy have been observed in the power spectra of the North, East and Up components of GPS station position residuals,and these anomalous periodic errors in station position residuals derived from two reprocessing campaigns are more prominent because of improved accuracy of error models,while odd draconitic signals of the second reprocessing campaign are weakened compared to the first reprocessing campaign, which can be attributed to the impact of Earth radiation pressure. What ＇s more,the power spectra of CODE＇s and ESA＇s residuals obtained by both GPS and GLONASS data shows distinct peak at period of about 8 days, close to the nominal ground repeat period of GLONASS satellites.