GRACE卫星非差精密定轨精度分析

Accuracy analysis of precise orbit determination of GRACE satellites based on zero-difference methods

随着星载GPS接收机性能和精密轨道、钟差产品精度的提高,星载GPS观测技术已成为确定CHAMP、GRACE和GOCE等低轨卫星精密轨道的重要手段。文章以GRACE卫星为例,分别利用非差弱动力法和非差运动学方法精密确定其轨道,并将结果和美国喷气动力实验室(JPL)事后精密轨道对比。结果表明:GRACE卫星非差弱动力法和非差运动学定轨精度均可达到厘米级;在使用相同的星历、钟差等产品时,弱动力法定轨精度略微优于运动学方法。此外,本文采用超快预报精密星历实时确定GRACE卫星轨道时精度也优于10cm。

Onboard GPS technique has been one of the most important technologies for POD（Precise Orbit Determination）recently due to the performance improvement of GPS receiver and the accuracy improvement of satellites ephemeris and clock error.In this paper,precise orbits of GRACE satellites are determined with both reduced-dynamic method and kinematic method and then are compared to the final science orbit form Jet Propulsion Laboratory.As the results show,both reduced-dynamic method and kinematic method can achieve the accuracy of centimeter.Besides,the reduced-dynamic method performs a little bit better with a higher accuracy than the kinematic method when using the same ephemeris and clock error products.Furthermore,the accuracy of real-time POD is also better than 10 cm.