HR: 13:50h
AN: G13A-02    [Abstracts]
TI: On Pertinent Use of GRACE K-Band Data
AU: * BALMINO, G
EM: Georges.Balmino@cnes.fr
AF: Groupe de Recherches de Geodesie Spatiale, 14, Avenue Edouard Belin, Toulouse, 31400 France
AU: BIANCALE, R
EM: Richard.Biancale@cnes.fr
AF: Groupe de Recherches de Geodesie Spatiale, 14, Avenue Edouard Belin, Toulouse, 31400 France
AU: BRUINSMA, S
EM: Sean.Bruinsma@cnes.fr
AF: Groupe de Recherches de Geodesie Spatiale, 14, Avenue Edouard Belin, Toulouse, 31400 France
AU: LEMOINE, J
EM: Jean-Michel.Lemoine@cnes.fr
AF: Groupe de Recherches de Geodesie Spatiale, 14, Avenue Edouard Belin, Toulouse, 31400 France
AU: FLECHTNER, F
EM: fletchne@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Dept. Geodesy and Remote Sensing Telegrafenberg A17, POTSDAM, 14473 Germany
AU: SCHMIDT, R
AF: GeoForschungsZentrum Potsdam, Dept. Geodesy and Remote Sensing Telegrafenberg A17, POTSDAM, 14473 Germany
AU: MEYER, U
AF: GeoForschungsZentrum Potsdam, Dept. Geodesy and Remote Sensing Telegrafenberg A17, POTSDAM, 14473 Germany
AB: Thanks to its novel K-band measurement between its twin satellites orbiting at 470 km altitude, the GRACE mission is bringing enormous progress in the knowledge of the Earth gravity field. These measurements are made available as three different types of information: biased range, range-rate and range-acceleration, which are provided normally at 5 s interval (level-1B data files). Each one of these data types presents advantages and disadvantages for deriving gravity field coefficients. Biased range, specified at best between 10-4 and 10-1 Hz, should bring the most complete information, although it is exposed to some mismodelled device behavior, which requires estimating many empirical parameters in semi-dynamical orbit processing mode. Range-acceleration information coupled with accelerometer data can be processed faster to generate directly linear combinations of gravity field coefficients, avoiding the costly process of integrating partial derivatives together with the accelerations; however the gravity signal is weakened in the low to middle frequency band by the double derivation and its recovery depends on the quality of the applied derivation process. Alternatively, range-rate data, which are mostly used by present day investigators, could be seen as a good compromise. In order to quantify the interest of these three data types for gravity field determination, we have investigated their impact in terms of information contents, performance in gravity field model recovery, computational convenience... A summary and the conclusions of this study based on test cases will be presented.
DE: 1200 GEODESY AND GRAVITY
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2005 Joint Assembly