Satellite Gravimetry As An Inverse Problem

Satellite Gravimetry is a hotspot in geodesy research, from which determining the high accuracy global earth's gravity field is one of the primary scientific objectives of physical geodesy. Launching of satellites CHAMP, GRACE and GOCE in plan can greatly increase the accuracy of gravity field. This dissertation has studied the model and algorithm of recovering gravity field model as an inverse problem. The main works and results are as follows:1. The background and progress of satellite gravity have been reviewed, as well as the model and algorithm of recovering gravity field. The basic acknowledges in gravity are given out, such as coordinate and time system, geopotential model.2. The preprocessing method of CHAMP accelerometry and attitude data, and a quadratic interpolation method for filling the attitude data gap is proposed, which has been verified by actual CHAMP data. Results show that the influences of interpolated attitude data can satisfy the requirement of accuracy in case of data gap less than 40 epochs.3. A new method for recovering the acceleration and coefficients of the geopotential model based on a inverse problem have been introduced, as well as the Least square and regularization solution of the algorithm.4. Simulation results based on CHAMP artificial orbits for acceleration and gravity recovery have been given out. It is showed that the recovered coefficients up to degree and order 36 can get a high solution of less than 4×10^-12(24 hour arc) if the orbits are noise-free, meanwhile, LS solution only have an accuracy of 10^-8 when 2cm white noise are added to the orbit in each of direction, and regularization method can efficiently improve the accuracy by one order.