Static Gravity Field Recovery and Accuracy Analysis Based on Reprocessed GOCE Level 1b Gravity Gradient Observations

Gravity gradient observations of GOCE (Gravity field and steady-state Ocean Circulation Explorer) provide important data support for the recovery of the short-wavelength part of the static gravity field, in which the influence of time-varying gravity signals should be reduced first. In this contribution, we carried out the following investigations on the static gravity field recovered from GOCE level 1b gravity gradient observations: (1) We updated the background models and according to the IERS2010 convention to remove the time-varying signals in the gravity gradient observations, and analyzed their influence on the subsequent static gravity field recovery; (2) We set up the 300 degrees and order(d/o) GOCE gravity gradient normal equations by the direct method with the reprocessed GOCE Level 1b gravity gradient observations; (3) In order to effectively treat the influence of polar gap, we combined the 300 d/o of the GOCE gravity gradient normal equation with 180 d/o Tongji-Grace02s normal equation and the Kaula’s regularization constraints; (4) GNSS/Leveling data, quasi-geoid model and DTU marine gravity anomaly are used to validate the accuracy of our combined solution, which shows that the accuracy of it is comparable to the state-of-art GOCO06s model.