LRI与KBR数据检核GRACE-FO卫星精密轨道

Precise Orbit Evaluation of GRACE-FO Satellite Using LRI and KBR Data

GRACE-FO卫星定轨精度直接影响其反演地球重力场,评估检核轨道数据精度是保证重力场反演效果的重要步骤。自该卫星升空以来,已在轨观测近2年6个月,尚未见对各时期卫星轨道的检核分析。针对以上情况,提出了利用LRI与KBR数据检核GRACE-FO卫星精密轨道的方法,引入了基于信噪比确定权重系数的星间距离组合观测量作为参考值,对764 d卫星轨道进行了精度检核,并与几何法轨道进行对比。实验结果表明,精密轨道在两星连线上的最大偏差为5.2 cm,RMS小于8 mm,近95%的差值在4 mm以内,2018年5月至2020年2月期间轨道数据在外符合精度和稳定性上优于2020年3月至2020年11月期间数据。

The orbital accuracy of satellites of GRACE-FO mission directly affects gravity recovery processes,and orbit evaluation is essential for reaching high inversion precision.The satellites have been surveyed in orbit for nearly 2 years and 6 months since they were launched,but there are not any accuracy analyses of satellites’orbits in different periods.In view of the above situation,the method of precision orbit evaluation for GRACE-FO mission’s satellites using LRI and KBR data is given in the paper.The weighted average of LRI and KBR data according to signal-to-noise ratio is introduced,regarding as reference value.Precision of 764 d satellite orbits is checked and compared with geometry orbit.Results show that the maximum deviation of precise orbits on the connecting line of barycenters of two satellites is 5.2 cm,RMS is less than 8 mm,and nearly 95%ones of orbits’deviation are less than 4 mm.Furthermore,the orbital data from 2018-05 to 2020-02 are better than those from 2020-03 to 2020-11 in terms of external coincidence accuracy and stability.