CHAMP Gravity Field Recovery with the Energy Balance Approach: First Results

Using the principle of energy conservation has been considered for gravity field determination from satellite observations since the early satellite era, see e.g. O’Keefe (1957), Bjerhammar (1968), Reigber (1969) or Ilk (1983). CHAMP is the first satellite to which the energy balance approach can be usefully applied, now that near-continuous orbit tracking by GPS is available, aided by accelerometry. Simulation studies show the feasibility of the approach. One concern is the sensitivity to velocity errors. As a next step CHAMP’s Rapid Science Orbits (RSO) are used. Their error level is sufficiently low to demonstrate the feasibility of the energy balance approach with real data. The accelerometer data (ACC), used for modeling the non-conservative forces, give rise to further concern.