HR: 08:15h
AN: G31A-02    [Abstracts]
TI: Analysis of the GRACE Gravity Sensor System
AU: * Frommknecht, B
EM: frommknecht@bv.tum.de
AF: IAPG TU Munich, Arcisstrasse 21, Munich, 80333, Germany
AU: Meyer, U
EM: meyeru@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam (GFZ), Telegrafenberg, Potsdam, 14473, Germany
AU: Schmidt, R
EM: rschmidt@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam (GFZ), Telegrafenberg, Potsdam, 14473, Germany
AU: Flechtner, F
EM: flechtne@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam (GFZ), Telegrafenberg, Potsdam, 14473, Germany
AB: The quality, strength and homogeneity of global gravity field models from the US-German gravity mission GRACE (Gravity Recovery and Climate Experiment, launched in 2002) is unprecedented and the derived models are superior to any previous satellite-only gravity field model. However, the predicted accuracy of these GRACE-only models (so-called GRACE baseline) has not yet been completely reached, thus still limiting a full geophysical exploitation of the GRACE mission data. Among others, the cause could lie in a degraded performance or interaction of elements of the gravity field sensor system. Another possible reason is that suboptimal signal processing methods have been applied. The gravity field sensor system consists of the K-Band distance measurements, the star sensor data for the orientation in inertial space, the accelerometer data and the GPS phase and code data. This investigation focuses on the analysis of the raw star sensor data and the related signal processing applied to generate higher level (so-called L1B) star sensor data which are used in the gravity recovery process. First, the performance of the raw star sensor data is discussed. Then the related signal processing is analyzed: In particular we investigate 1) the combination of star sensor data from the two available sensor heads aboard each GRACE satellite and 2) the combination of the star sensor and the angular acceleration data to derive improved(?) L1B star sensor data. The results are discussed and the expected impact on the gravity field recovery is evaluated.
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2007 Fall Meeting