中文摘要：

研究利用地面及星载GPS数据同时确定低轨卫星（CHAMP、GRACE）与GPS导航卫星精密轨道的联合定轨方法。针对不同测站数量和分布,设计不同的轨道解算方案,并基于PANDA软件平台进行数值分析。计算结果表明,由于低轨卫星对空间观测几何结构的增强,联合定轨较“两步法”定轨在定轨精度方面有所提高。

英文摘要：

The combined orbit determination method for low earth orbit satellite and GPS satellite using ground-and space-based GPS tracking data is studied. Some tests were designed according to different number and distribution of ground GPS tracking stations and implemented by use of PANDA （ Positioning And Navigation Data Analysis） software. Numerical results show that better orbit precision with the method can be obtained as compared to ＂two-step orbit determination method＂, because this method profits from the low earth orbit satellite which has greatly enhanced the spatial measurement geometry.