Analysis of one month of CHAMP state vector and accelerometer data for the recovery of the gravity potential

摘要

The energy conservation method is based onknowledge of the state vector and measurements of nonconservativeforces. This is or will be provided by CHAMP,GRACE and GOCE. Here the analysis of one month ofCHAMP state vector and accelerometer data is described. The energy conservation method is used to estimate thegravity potential at satellite altitude. When doing so we considerthe tidal potential from the sun and the moon, the explicittime variation of the gravity potential in inertial spaceand loss of energy due to external forces. Fast Spherical Collocation have been used to estimate agravity field model to degree and order 90, UCPH2002 04.This gravity field model is compared to EGM96 and EIGEN-2. The largest differences with respect to EGM96 arefound at those places where the gravity data used to determineEGM96 had the largest uncertainty. EIGEN-2 andUCPH2002 04 are similar, though there are some differencesin Antarctica and Central Asia.