A new global Earth's gravity field model from satellite orbit perturbations: GRIM5-S1

A new model of the Earth's gravity field, called GRIM5-S1, was prepared in a joint German-French effort. The solution is based on satellite orbit pert urbation analysis and exploits tracking data from 21 satellites to solve si multaneously for the gravitational and ocean tide potential and tracking st ation positions. The satellite-only solution results in a homogeneous repre sentation of the geoid with an approximation error of about 45 cm in terms of 5 x 5 degree block mean values, and performs globally better in satellit e orbit restitution than any previous gravity field model. The GRIM5 normal s, which were generated taking into account the latest computational standa rds, shall be the reference for use during the coming geopotential satellit e mission CHAMP and should provide new standards in computing orbits of nex t altimetric missions like Jason and ENVISAT. The GRIM5-S1 normals also giv e the basis for the tracking/surface data combined solution GRIM5-C1.