中文摘要：

给出了联合定轨的数学模型，从6个试验的结果说明低轨卫星的星载GPS观测值对GPS卫星精密定轨的贡献。单天解的结果表明，相对于仅使用43个地面跟踪站的定轨结果，增加3颗低轨卫星的观测数据可以使GPS卫星的轨道准确度平均提高40％，即使仅用21个地面站和3颗低轨卫星也可以使GPS卫星的轨道与IGS最终轨道之差的RMS在5cm左右。

英文摘要：

Satellite precision orbit determination （POD） is always one of the focuses in geodesy and geodynamics. Integrated adjustment of LEO and GPS for POD is reported. That means the orbits of GPS satellites and LEOs are determined simultaneously. At first, the mathematical description of the integrated adjustment is given. Then 6 cases are described to illuminate the contribution of LEO to GPS POD. It is shown that the improvement can reach 40 on average when 3 LEOs are included if 43 stations are used. Even if only 21 ground stations plus 3 LEOs are used for GPS orbit determination, about 5.0 cm accuracy from IGS final orbit can be achieved with only one day＇s data. In this process, the along and cross components of the GPS orbit benefit much and the systematic error vanishes or diminishes. It is mainly attributed to the strengthened geometry of GPS tracking network and no tropospheric delay for space-borne GPS observations.