GPS/BDS联合定轨对北斗卫星轨道的影响分析

为研究不同条件下GPS/BDS联合定轨对北斗卫星轨道的影响，在不同测站分布条件下采用不同定轨弧长分别进行GPS/BDS联合定轨和BDS独立定轨，并从轨道重叠弧段不符值、与MGEX分析中心产品比较以及卫星激光测距检核残差3个方面详细比较两种定轨方法的精度。结果表明，区域网条件下，联合定轨能够显著提升1 d解北斗IGSO/MEO卫星的轨道精度，但对3 d解的北斗各类卫星定轨精度的改善较小；全球网条件下，无论是采用1 d还是3 d定轨弧长，联合定轨均能在一定程度上改善北斗IGSO/MEO卫星轨道沿迹方向和法向的精度，但对径向绝对精度的改善较小；而对于北斗GEO卫星，全球网条件下的联合定轨对其轨道各方向精度的影响均较小。

Effect Analysis of GPS/BDS Combined Orbit Determination on Beidou Satellite Orbits

In order to study the effect of GPS/BDS combined orbit determination(OD) on Beidou navigation satellite system(BDS) orbits in different cases, GPS/BDS combined and BDS-only OD experiments are conducted respectively, adopting different lengths of OD arc and different distributions of ground tracking network. Precision and accuracy of OD results of these two methods are compared thoroughly by orbit overlapping arc difference, difference with MGEX products and satellite laser ranging(SLR) residuals. The results show that, with the regional tracking network, GPS/BDS combined OD can noticeably improve the precision and accuracy of BDS IGSO/MEO satellite orbits for 1-day solution but only have marginal improvement on that of all types of BDS satellite orbits for 3-day solution. With the global tracking network, combined OD can improve the precision in along-track and cross-track directions of BDS IGSO/MEO satellite orbits for both 1-day and 3-day solutions but have minimal improvement on the accuracy in radial direction. Furthermore, combined OD barely has an effect on the precision and accuracy in all directions of BDS GEO satellite orbits.