GOCE SGG and SST quick-look gravity field analysis

The purpose of quick-look analysis in the framework of the GOCE data processing architecture is to analyse partial data sets of satellite gravity gradiometry (SGG) and satellite-to-satellite tracking in high-low mode (hl-SST), in order to derive a diagnosis of the system performance. The semi-analytic (SA) method for gravity field recovery from GOCE observations, which is based on Fast Fourier Transform, is used. From a theoretical point of view, a number of requirements (circular, exact repeat orbit, uninterrupted measurement time series) have to be fulfilled. However, in the present paper it is demonstrated, that the SA approach can also be applied in the practical case of non-circular, nonrepeat orbits, and data gaps in the GOCE measurement time series. The performance of this approach is assessed in 5 case studies on the basis of a realistic closed-loop simulation.