Gravity Field Determination at the AIUB- the Celestial Mechanics Approach.

Abstract. We present the gravity field model AIUB-CHAMP01S, which has been generated using the Ce-lestial Mechanics approach. GPS-derived kinematic positions of low Earth orbiters (LEOs) are used as pseudo-observations to solve for the Earth’s gravity field parameters in a generalized orbit determination problem. Apart from normalized spherical harmonic (SH) coefficients, arc-specific parameters (e.g., ac-celerometer calibration parameters, dynamical pa-rameters, or pseudo-stochastic parameters) are set up and normal equations are written for all daily LEO arcs. The daily normal equations are combined to weekly, monthly, and annual systems before inver-sion. The parametrization can be modified on the nor-mal equation level without a new time-consuming set up of the daily normal equations. The results based on one year of CHAMP data demonstrate that the Ce-lestial Mechanics approach is comparable in quality with other approaches. Key words. CHAMP, gravity field determination, pseudo-stochastic parameters, accelerometer data