HR: 1340h
AN: G33C-0052    [Abstracts]
TI: Gravity Field Recovery with Simulated GOCE Observations
AU: * Marty, J
EM: jean-charles.marty@cnes.fr
AF: CNES, Space Geodesy Department, 18, Avenue E. Belin, Toulouse, 31401 France
AU: Bruinsma, S
EM: sean.bruinsma@cnes.fr
AF: CNES, Space Geodesy Department, 18, Avenue E. Belin, Toulouse, 31401 France
AU: Balmino, G
EM: georges.balmino@cnes.fr
AF: CNES, Space Geodesy Department, 18, Avenue E. Belin, Toulouse, 31401 France
AU: Abrikosov, O
EM: abrik@gfz-potsdam.de
AF: GFZ, Department 1 Geodesy and Remote Sensing, Telegrafenberg A17, Potsdam, 14473 Germany
AU: Foerste, C
EM: foer@gfz-potsdam.de
AF: GFZ, Department 1 Geodesy and Remote Sensing, Telegrafenberg A17, Potsdam, 14473 Germany
AU: Rothacher, M
EM: rothacher@gfz-potsdam.de
AF: GFZ, Department 1 Geodesy and Remote Sensing, Telegrafenberg A17, Potsdam, 14473 Germany
AB: Numerical simulations of the gravity field parameter recovery using the direct method, with satellite positions as pseudo observations instead of simulated GPS Satellite-to-Satellite (SST) tracking data, and with gravity gradients (SGG data), were done and are ongoing in the framework of the European GOCE Gravity Consortium test and validation plan for GOCE mission data processing. This work shows the latest results from the CNES and GFZ software packages, GINS and EPOS, respectively. After the iterative least-squares orbit adjustment procedure has converged to the highest attainable precision level, the gravity field normal equations are computed in a subsequent step. These SST normal equations, representing the long wavelength gravity field signal, are then reduced for arc-dependent parameters (i.e. state vector at epoch, empirical parameters) and cumulated over the entire observation period. Secondly, the gravity gradient measurements (SGG) are processed, taking into account the coloured noise in these data, and yield (high resolution) normal equations. They are combined with the SST normal equations and the gravity field and gradiometer common mode calibration parameters are simultaneously estimated. The coloured noise in the SGG data is based on the latest and realistic gradiometer specifications. The precision in the measurement bandwidth is approximately 3-5 milliEotvos, but rapidly decreasing for lower frequencies. Due to this behaviour, the observation equations have to be filtered in order to obtain the most accurate recovery. The filter algorithm, design and results are presented to considerable detail since this particular step is the key element that will enable the achievement of the GOCE mission objectives from the ground segment point of view.
DE: 1200 GEODESY AND GRAVITY
DE: 1214 Geopotential theory and determination (0903)
SC: Geodesy [G]
MN: Fall Meeting 2005