A simple computation technique for improving the short term stability and the robustness of GPS TAIP3 common-views
A simple computation technique for improving the short term stability and the robustness of GPS TAIP3 common-views
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一种提高 GPS TAIP3 共视短期稳定性和鲁棒性的简单计算技术
DOI：
10.1109/eftf-ifc.2013.6702196
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
P. Uhrich
中科院分区：
文献类型：
--
作者：
G. Rovera;B. Chupin;M. Abgrall;P. Uhrich
为了提高全球定位系统（GPS）卫星共视图（CV）的短期稳定性和鲁棒性，提出了一种新的简单方法。我们使用在两个GPS载波上广播的电离层自由线性组合p码数据，称为TAIP3，数据文件根据通用GNSS时间传输标准（CGTTS）格式构建。我们不是通过在每个CGTTS采样历元计算的平均值周围使用给定的过滤器来平均异常值，而是从每日CV文件的线性拟合中平均异常值。我们分析了超过200天的数据的结果。在远程站之间的短基线上，我们看到每日滤波用于CV计算的平均卫星数量几乎是从历元滤波获得的数量的两倍，从而增加了时间传递的鲁棒性。在时间传递的短期稳定性方面，白相位噪声调制的改善幅度大于根号2，高于预期。在长期基线上，在10000秒到1天之间，改善的短期稳定性大约小了两倍，同时，经过CV计算过滤后的剩余卫星数量平均增加了20%以上。我们研究了导致这两个标准之间差异的单一事件，并得出结论，日常方法在所有情况下都提供了最好的结果。这种自动滤波技术可能对任何基于代码数据的GNSS时间传输都很有用。
We propose a new simple technique to improve the short term stability and the robustness of Common-Views (CV) of Global Positioning System (GPS) satellites. We use the ionosphere free linear combination of P-code data broadcast on both GPS carriers, called TAIP3, the data files being built according to the Common GNSS Time Transfer Standard (CGTTS) format. Instead of averaging the outliers out by using a given filter around a mean value computed for each CGTTS sampling epoch, we average the outliers out from a linear fit on daily CV files. We analyze the results over more than 200 d of data. Over a short baseline between remote stations, we see that the average number of satellites left by the daily filtering for the CV computation is almost twice as large as the number obtained from the epoch filtering, increasing that way the robustness of the time transfer. On the short term stability of the time transfer, the white phase noise modulation is improved by a factor larger than the square root of 2, above what was expected. Over a long baseline, the improved short term stability is about twice smaller between 10 000 s and 1 d, together with an average increase of more than 20 per cent on the number of satellites left after filtering for the CV computation. We study the singular event which causes the discrepancy between these two criteria, and conclude that the daily approach is providing the best results in all cases. This automated filtering technique might be useful for any GNSS time transfer based on code data.