MGEX精密星历卫星钟差精度分析

IGS的多GNSS实验项目(Multi-GNSS Experiment,MGEX)所提供的事后精密卫星钟差作为一种基础性的GNSS数据产品。在分析MGEX事后精密钟差产品特点的基础上,设计用于卫星钟差精度评价的内符合精度指标和外符合精度指标。基于该指标对MGEX的欧洲定轨中心(CODE)、波茨坦地学中心(GFZ)和武汉大学(WUM)三个分析中心2015年的事后精密卫星钟差进行精度分析。结果表明:GFZ的卫星钟差精度相对最差,CODE的卫星钟差内符合精度最高,WUM的卫星钟差外符合精度最高,三个分析中心的卫星钟差内外符合精度平均值分别为0.307ns和0.322ns;随着GPS系统的更新其卫星钟差的精度有所提高,同时GPS系统中BLOCK IIF铯钟的钟差内外符合精度均最高;CODE的卫星钟差内符合精度随卫星钟类型的不同变化相对较小。

Accuracy assessment for IGS MGEX precise ephemeris satellite clock bias

The final precise satellite clock bias(SCB)from the IGS Multi-GNSS Experiment(MGEX)is a kind of basic GNSS data product,w hich plays an important role in high precision navigation,positioning and timing.Based on analyzing the characteristics of the MGEX SCB,this paper designs two precision indexes which are used to respectively represent the internal accord accuracy and external accord accuracy of the SCB.Using these two indexes,it assesses the accuracy of the final precise SCB in 2015 from three MGEX Analysis Centers(ACs),including the Center for Orbit Determination in Europe(CODE), Deutsches GeoForschungsZentrum(GFZ)and Wuhan University(WUM).The result of the assessment shows that the accuracy of the SCB data from GFZ is relatively worse compared with that of CODE and WUM,and the SCB data from CODE has the highest internal accord accuracy while the SCB data from WUM has the highest external accord accuracy.The average values of internal and external accord accuracy for the SCB data from three ACs are respectively 0.307 ns and 0.322 ns.With the updating of GPS,the accuracy of its SCB data is improved,and the SCB of the BLOCK IIF cesium atomic clock has the highest internal and external accord accuracy compared with that of other GPS satellite clocks.In addition,the internal accord accuracy of SCB from CODE has relatively small variations with the change of satellite clock types.