Integrated Sensor Analysis for GRACE – Development and Validation

The focus of this article is on the accelerometer on board the two GRACE (Gravity Recovery and Climate Experiment) satellites. In a first analysis the accelerometer system is studied. The behavior of the test mass and its capacitive feedback system is simulated in the time and the frequency domain for one degree of freedom. Only linear accelerations are considered so far. The second part of the analysis is about the practical implementation of the simulation model: Non-gravitational forces were derived from the GFZ (GeoForschungsZentrum) EPOS (Earth Parameter and Orbit System) software. In a closed loop the accelerometer measurements derived from these data in connection with simulated tracking data have been used for orbit recovery including the estimation of biases and scale factors for the accelerometer data. Details and results of this procedure are presented.Key words. GRACE – sensor analysis – accelerometer