Precise orbit determination of the Fengyun-3C satellite using onboard GPS and BDS observations
Precise orbit determination of the Fengyun-3C satellite using onboard GPS and BDS observations
复制标题
利用星载GPS和北斗观测对风云三号C卫星进行精密定轨
DOI：
10.1007/s00190-017-1027-9
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发表时间：
2017-11-01
影响因子：
4.4
通讯作者：
Liao, Mi
中科院分区：
文献类型：
--
作者：
Li, Min;Li, Wenwen;Liao, Mi
中国气象卫星风云三号C（FY-3C）上搭载的全球导航卫星系统掩星探测仪跟踪GPS和北斗信号进行轨道确定。利用2015年3月FY-3C星载双频GPS和BDS数据，对一个月的数据进行了分析。从数据量和码多径误差两个方面对机载BDS和GPS的测量质量进行了评估。严重的多径误差的BDS码的范围内观察到，特别是高海拔的BDS中地球轨道卫星（MEO）。将码多径误差估计为网格中的分段线性模型，并应用于精密定轨（POD）计算。首先利用GPS数据对风云三号C卫星进行定轨，通过重叠比较，得到3DRMS（均方根）轨道一致性约为2.7 cm的定轨结果，并以此为参考轨道，对GPS与BDS组合定轨以及基于BDS的定轨精度进行了评估。结果表明，BDS地球同步轨道卫星（GEO）的加入会严重降低POD精度。在有GEO参与的情况下，组合POD和基于BDS的POD在3D RMS中的轨道估计精度分别为3.4和30.1 cm。然而，如果不包括BDS GEO，则组合POD可以达到相对于GPS POD的类似精度，显示约0.8 cm的轨道差，而基于BDS的POD的轨道精度可以提高到8.4 cm。这些结果表明，单独使用机载BDS数据的POD性能可以达到优于10厘米的精度，只有5个BDS倾斜地球同步卫星轨道卫星和3个MEO。由于全球导航卫星系统接收器在其最大信道上只能跟踪六颗北斗卫星进行轨道定位，因此可以预期，如果在没有这种限制的情况下产生更多的观测数据，利用北斗卫星系统机载数据的POD的性能将进一步提高。
The GNSS Occultation Sounder instrument onboard the Chinese meteorological satellite Fengyun-3C (FY-3C) tracks both GPS and BDS signals for orbit determination. One month's worth of the onboard dual-frequency GPS and BDS data during March 2015 from the FY-3C satellite is analyzed in this study. The onboard BDS and GPS measurement quality is evaluated in terms of data quantity as well as code multipath error. Severe multipath errors for BDS code ranges are observed especially for high elevations for BDS medium earth orbit satellites (MEOs). The code multipath errors are estimated as piecewise linear model in grid and applied in precise orbit determination (POD) calculations. POD of FY-3C is firstly performed with GPS data, which shows orbit consistency of approximate 2.7 cm in 3D RMS (root mean square) by overlap comparisons; the estimated orbits are then used as reference orbits for evaluating the orbit precision of GPS and BDS combined POD as well as BDS-based POD. It is indicated that inclusion of BDS geosynchronous orbit satellites (GEOs) could degrade POD precision seriously. The precisions of orbit estimates by combined POD and BDS-based POD are 3.4 and 30.1 cm in 3D RMS when GEOs are involved, respectively. However, if BDS GEOs are excluded, the combined POD can reach similar precision with respect to GPS POD, showing orbit differences about 0.8 cm, while the orbit precision of BDS-based POD can be improved to 8.4 cm. These results indicate that the POD performance with onboard BDS data alone can reach precision better than 10 cm with only five BDS inclined geosynchronous satellite orbit satellites and three MEOs. As the GNOS receiver can only track six BDS satellites for orbit positioning at its maximum channel, it can be expected that the performance of POD with onboard BDS data can be further improved if more observations are generated without such restrictions.