GOCE Quality Analysis Using Cross-Overs
Brieden, Phillip; Mueller, Juergen
Institute of Geodesy, Leibniz Universitšt Hannover, GERMANY

The GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite mission is currently operating for about three years. Terabytes of data has been collected that reflect the mass distribution on Earth. Beside the main objective of GOCE to determine static gravity field, the time-varying effects are even examined due to its long mission lifetime. The processing of gradiometer data has been renewed in 2012 and the fourth generation of GOCE gravity field models is announced for the 2nd quarter of 2013, which will be based on re-processed data. All in all, GOCE is a very successful mission, of which the data is and will be used in many research fields. In order to obtain even better results its orbit is being lowered, which will further improve the accessible spatial resolution. GOCE's main measurement quantity is the gravitational gradients. These carry the information about fine structures of the mass distribution on Earth and represent the most important data product of the mission. In order to assess the gradients' quality, various methods are investigated. One of these is the cross-over approach, in which gravitational gradients are compared in satellite track cross-overs (XO). The presentation will give insight into the treatment of altitude and attitude differences between the positions of the GOCE satellite in each XO. We will discuss the effect of partly used model gradients in the XO analysis. Results will show the significantly improved data quality after data pre-processing and underline the high quality of GOCE gravitational gradients.