基于新型星间距离插值法（IRIM）开展了K波段星间测距仪的星间距离影响地球重力场精度的论证研究。首先，基于GPS接收机轨道、K波段测距仪星间距离、加速度计非保守力等原始卫星观测数据，首次通过将高精度的星间距离引入相对轨道位置矢量的星星连线方向建立了星间距离插值观测方程；其次，通过不同点数插值公式的相互对比，9点星间距离插值公式可有效提高地球重力场的反演精度；再次，基于美国喷气推进实验室（JPL）公布的2008年的GRACE Level-1B实测数据，建立了120阶全球重力场模型WHIGG-GEGM01S，在120阶处，累计大地水准面和累计重力场异常的精度分别为1.098×10-1 m和1.741×10-6 m/s2；最后，基于美国、欧洲和澳大利亚的GPS/Levelling数据检验了WHIGG-GEGM01S的正确性。

 

Efficient Accuracy Improvement of GRACE Global Gravitational Field Recovery using a New Inter-satellite Range Interpolation Method

　New studies on the influence of inter-satellite range on the accuracy of the Earth’s gravitational field recovery were carried out based onthe Inter-satellite Range Interpolation Method (IRIM). Firstly, the IRIM observation equation by introducing the precise inter-satellite range into the Line-Of-Sight (LOS) component of the relative orbital position vector was established for the first time using the original satellite observations including the orbital position of the spaceborne Global Positioning System (GPS) receiver, the inter-satellite range of the K-Band Ranging (KBR) system and the non-conservative force of the accelerometer (ACC). Secondly, the nine-point IRIM formula is shown by a comparison of multipoint IRIM formulas to be preferable for effectively improving the accuracy of the Earth’s gravitational field recovery. Thirdly, the WHIGG-GEGM01Sglobal gravity field model, complete up to degree and order 120, is produced using the GRACE Level-1B data products, acquired during 2008-01-01 to 2008-12-31 and releasedby the American Jet Propulsion Laboratory (JPL). Cumulative geoid height and gravity anomaly errors are 1.098×10-1 m and 1.741×10-6 m/s2 at degree 120, respectively. Finally, the availability of the WHIGG-GEGM01S model is validated by the GPS/Levelling observations in the U.S., Europe and Australia.

图1  GRACE全球重力场模型精度对比

图2  WHIGG-GEGM01S模型全球大地水准面分布

Wei Zheng, Houtse Hsu, Min Zhong, Meijuan Yun. Efficient accuracy improvement of GRACE global gravitational field recovery using a new Inter-Satellite Range Interpolation method. Journal of Geodynamics, 2012, 53: 1-7.