The CHAMP-only earth gravity field model EIGEN-2

The German small geoscientific satellite CHAMP flies around the Earth since July 2000 in a highly inclined orbit with an altitude of initially 450 km and meanwhile at about 400 km. From the gravitational orbit perturbations, exploiting GPS-CHAMP satellite-to-satellite tracking and on-board accelerometer data over a time span of altogether six months, a new long-wavelength global gravity field model, called EIGEN-2, has been derived in a German/French effort. Thanks to CHAMP's dedicated orbit configuration, continuous GPS tracking and in-orbit measurement of non-gravitational satellite accelerations, the new CHAMP-only solution provides the geoid and gravity with an accuracy of 10 cm and 0.5 mGal, respectively, at a half wavelength resolution of 550 km. This is an improvement by almost one order of magnitude compared to any multi-satellite pre-CHAMP satellite-only gravity field model.