METHOD OF GRAVITY FIELD INVERSION WITH COMBININGGRACE ORBITS AND RANGERATE OBSERVATIONS
Zhang Xingfu 1) ; and Shen Yunzhong 2)
1)Department of Surveying and Mapping, Guangdong University of Technology, Guangzhou 510006 2)Department of Surveying and Geomatics, Tongji University, Shanghai 200092
Abstract The dynamical method based on the precision orbits and rangerate data of GRACE for recovering gravity field model is discussed, and the gravitational potential coefficients and the satellite’s initial state error can be estimated simultaneously with this algorithm. The gravity field models are recovered with the combined observations with different orbits accuracy and different sampling rate rangerate of GRACE, finally the accuracy of gravity field model recovery are analyzed. The simulated results show that the accuracy of accelerometer from (1.0×10 -10-1.0×10 -9 m/s 2 is suitable for the combined recovery algorithm,as the rangerate with 1 μm/s accuracy , satellite’s position with 2-3 cm accuracy, and satellite’s velocity with 0.1-0.5 mm/s accuracy. When the accuracy of rangrate is improved from 1 um/s to 0.1 um/s, the accuracy of recovered model is improved correspondingly; the accuracy of the recovered model based on same accuracy observations with sampling rate of 5 seconds is the hightest accurate.
