1) Key Laboratary of Dynamic Geodesy,Institute of Geodesy and Geophysics, CAS, Wuhan 4300772) Disaster Prevention Research Institute, Kyoto University, Uji, Kyoto 611-0011, Japan3) Department of Applied Physics, Wuhan University of Science and Technology, Wuhan 430081
Abstract The GRACE Earth’s gravitational field complete up to degree and order 120 is recovered based on different orbital altitude according to the improved energy conservation principle. The simulative results show: Firstly, with the decrease of orbital altitude per 100 km, atmospheric drag will increase 10 times approximately, and the unstable work environment of satellite platform will influence the measuring accuracy of GRACE key payloads.Secondly, the highfrequency signals of Earth’s gravitational field will be attenuated quickly. Attenuation factor comes to 0.221 based on 500 km orbital altitude at degree 20, and attenuation effects increase 9.621 times, 92.857 times, 418.957 times and 1895.369 times at degree 50th, degree 80th, degree 100th and degree 120th, respectively. Thirdly, low orbital altitude is good for improving the accuracy of Earth’s gravitational field recovery. Cumulative geoid height error is at the level of 17.316 cm using 500 km orbital altitude at degree 120th, and the accuracies improve 1.566 times, 4.502 times and 10.871 times as using 450 km, 400 km and 350 km orbital altitude combined with GRACE other indexes published by JPL, U. S., respectively; Lastly, orbital altitude designed as 350 ~ 400 km for future satellitetosatellite tracking model will be propitious to the Earth’s gravitational field recovery complete up to degree and order 120.
