Effect of Time-Varying Gravity Signal on Satellite Gravity Gradient Observations

Satellite gravimetry is considered as one of the most powerful techniques for determining the global gravity field at high resolution and accuracy. At present, our country is implementing a satellite gravity project which is necessary to develop a preprocessing method and software for satellite gravity gradient observations. The effects of tide and non-tide signals on GOCE satellite gravity gradient observations were systematically explored. The results show that: (1) The magnitude of time-varying correction was at the 0.1mE level, and slightly lower than the designed accuracy (3.2 mE) of the GOCE satellite. This colored noise must be removed in the pretreatment. (2) The magnitude of tide (0.1 mE) was bigger than non-tide effects(0.01 mE). Thus, the correction accuracy for the time-varying gravity field must be determined by the tide. (3) These results correspond to the official GOCE, which validates the effectiveness of our calculating method and results.