The project CAKAO focused on the improvement of time-variable gravity field information by consistent combination of two different measurement techniques. Gravity field estimates derived from GPS tracking of low Earth orbit satellites were augmented by incorporating observations of station displacements on ground. Permanently operating GPS stations worldwide provide highly accurate measurements of loading-induced displacements, which were used to supplement and improve the satellite based measurements. Especially for continental areas, which are of high interest for different applications, e.g. hydrology, an improvement in terms of accuracy was achieved.