HR: 0800h
AN: U21C-0615    [Abstracts]
TI: High-Resolution Analysis and Modeling of GRACE Accelerometer Observations
AU: * Flury, J
EM: jflury@csr.utexas.edu
AF: Center for Space Research University of Texas, 3925 W Braker Ln, Austin, TX 78759, United States
AU: Bettadpur, S
EM: srinivas@csr.utexas.edu
AF: Center for Space Research University of Texas, 3925 W Braker Ln, Austin, TX 78759, United States
AU: Tapley, B D
EM: tapley@csr.utexas.edu
AF: Center for Space Research University of Texas, 3925 W Braker Ln, Austin, TX 78759, United States
AB: A better understanding and modeling of high-resolution GRACE accelerometer data serves three purposes: (1) to ensure that the best possible data are used in the GRACE gravity field processing, (2) to obtain precise and clean non-gravitational accelerations for aeronomy research, and (3) to understand and quantify disturbances which may play a role for future space-borne accelerometry. The external non-gravitational forces acting on the twin GRACE satellites are superimposed by a complex signal pattern of satellite-induced effects, originating from switching events in electrical circuits of on-board heaters and magnetic torquers, from vibrations and thruster accelerations. For each of these processes, we compared and averaged 10 Hz acceleration signals from a large number of events from long accelerometer time series. The analysis results provide constraints, e.g., on thrust accuracy, misalignments, and vibration frequencies. These constraints may help to understand the underlying physics. We modeled and reduced acceleration signals due to thrusters and heater switching and obtained considerably smoother and cleaner signals of external non-gravitational accelerations which may be useful for applications in aeronomy research.
DE: 1214 Geopotential theory and determination (0903)
DE: 1220 Atmosphere monitoring with geodetic techniques (6952)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1241 Satellite geodesy: technical issues (6994, 7969)
DE: 1243 Space geodetic surveys
SC: Union [U]
MN: 2007 Fall Meeting