Galileo orbit determination using combined GNSS and SLR observations
Galileo orbit determination using combined GNSS and SLR observations
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DOI：
10.1007/s10291-013-0361-5
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发表时间：
2015-01-01
期刊：
影响因子：
4.9
通讯作者：
Montenbruck, O.
中科院分区：
文献类型：
--
作者：
Hackel, S.;Steigenberger, P.;Montenbruck, O.
第一批两颗伽利略在轨验证卫星于2011年10月发射，并于2012年初开始在所有频率上连续传输信号。这两颗卫星都配备了两种不同类型的时钟，即Ru钟和氢脉泽。根据两个测试期，评估了基于全球导航卫星系统(GNSS)和卫星激光测距(SLR)观测的伽利略轨道确定的质量。估计的卫星时钟参数被用作轨道质量指标：阿兰偏差中轨道周期的起伏表明仅由全球导航卫星系统确定的轨道中的系统误差。如果再考虑SLR观测，这些误差几乎为零。由于组合降低了内部一致性，SLR反射器的偏移量移动了+5厘米，从而提高了轨道一致性和精度。减少仅由全球导航卫星系统确定的轨道的系统误差的另一种方法是对相对于线性模型的时钟估计采用约束。一般来说，可以达到1分米的轨道精度。
The first two Galileo In-Orbit Validation satellites were launched in October 2011 and started continuous signal transmission on all frequencies in early 2012. Both satellites are equipped with two different types of clocks, namely rubidium clocks and hydrogen masers. Based on two test periods, the quality of the Galileo orbit determination based on Global Navigation Satellite System (GNSS) and Satellite Laser Ranging (SLR) observations is assessed. The estimated satellite clock parameters are used as quality indicator for the orbits: A bump at orbital periods in the Allan deviation indicates systematic errors in the GNSS-only orbit determination. These errors almost vanish if SLR observations are considered in addition. As the internal consistency is degraded by the combination, the offset of the SLR reflector is shifted by +5 cm, resulting in an improved orbit consistency as well as accuracy. Another approach to reduce the systematic errors of the GNSS-only orbit determination employs constraints for the clock estimates with respect to a linear model. In general, one decimeter orbit accuracy could be achieved.