BDS卫星精密钟差性能综合评定

Accuracy evaluation of BDS satellite precise clock bias

为了进一步服务于北斗卫星导航系统(BDS)的精确导航、定位和授时,对BDS卫星的高精度钟差数据进行综合评定:分析星地双向时间比对(TWTT)及精密定轨与时间同步(ODTS)2种卫星钟差确定方法的特点与差异;然后从卫星钟差数据的连续性、内符合精度、外符合精度以及计算得到的时域稳定度4个方面,对国际全球卫星导航系统服务组织(IGS)分析中心提供的BDS ODTS卫星钟差和TWTT卫星钟差的数据质量进行分析和讨论。分析认为,IGS不同分析中心的数据缺失率规律相似,但是德国地学研究中心(GFZ)的缺失率最高,欧洲定轨中心(CODE)的缺失率相对较低;TWTT精密卫星钟差的内符合精度最高,数据拟合精度即均方根(RMS)为0.37 ns,CODE、GFZ、武汉大学GNSS中心(WHU)钟差产品受到定轨误差等其他因素的影响,其拟合精度相对较低,RMS值分别为0.53、0.71、0.65 ns;4种精密星钟产品的天稳定度指标均到达1×10^-14量级,但TWTT结果所反映的噪声特性与3个分析中心的产品略有不同。

In order to further service for the precise navigation,positioning and timing of BDS,the paper comprehensively evaluated the high-precise satellite clock bias data of BDS:the characteristics and differences of two satellite clock difference determination methods as TWTT and ODTS were analyzed;and the data quality of ODTS satellite clock error and TWTT satellite clock error for BDS provided by IGS were analyzed and discussed from four aspects of the continuity,the internal coincidence accuracy,the external coincidence accuracy and the calculated time-domain stability of satellite clock bias.Result showed that the data loss rates of the different analysis centers of IGS were similar,among which GFZ was with the highest total loss rate and CODE with the lowest;TWTT has the most accurate internal coincidence accuracy with fitting precision(RMS)0.37 ns,while the fitting precision(RMS)of CODE,GFZ and WHU was 0.53,0.71 and 0.65 ns respectively lower due to the influence of orbiting error and other factors;and the daily stability of all these products could reach the level of 1×10-14,but the noise characteristics of TWTT showed a difference from those of the three analysis centers.