Study On Gravity Field Detection For Space-Borne Gravitational Wave Detection Program "Taiji"

Gravity field is one of the fundamental physical fields of a planet.High-precision and high-resolution global gravity field information has significant strategic scientific applications in satellite navigation,geodesy,geophysics,hydrology and environmental science,resource exploration and so on.Great efforts have been paid in satellite gravity since the last century,with a variety of measurement modes such as high-low,low-low satellite-to-satellite tracking,and gravity gradient measurement successfully implemented at the beginning of this century,providing high-precision and high-resolution global gravity field observations.Taiji-1 is the first technology demonstration satellite of the Taiji program of China’s space-borne gravitational wave antenna.Based on the orbit design and payload of the satellite,Taiji-1 can be viewed as China’s first high-low satellite-to-satellite tracking mode of the Earth gravity recovery mission,used for global gravity field model calculation.This paper mainly studies the theory and method of Taiji-1 satellite data processing and Earth gravity field model recovery.The main research contents and results of this paper are as follows.The research status of satellite gravity field research both at home and abroad was summarized.The basic principles of using satellite-to-satellite tracking technology based on energy method to invert the Earth gravity field model are expounded,along with the calculation method of related mathematical models.A software platform including data preprocessing,gravity field model calculation,and result accuracy verification was established,which can be used for gravity recovery missions at home and abroad.The importance of satellite data preprocessing for energy method inversion of the Earth gravity field was discussed.The data preprocessing scheme for observations from Taiji-1 was established.The discontinuities and anomalies in the satellite observations were identified and subtracted to ensure the reliability of the calculation results.The low-degree harmonics of the global gravity field model were successfully built from Taiji-1’s observations.Compared with EGM2008 and gravity models from other satellite gravity missions,the overall discrepancies were within.The capability of the Taiji-1satellite serving as a satellite gravity mission has been demonstrated and confirmed.The result indirectly verified the ability of Taiji-1 satellite for whole-star collaboration,and accumulated experience for the data processing and gravity field inversion of other domestic gravity satellites in the future.