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Numerical simulation of the gravity field recovery from GOCE mission data

Sean Bruinsma(1), Georges Balmino(1) , and Jean-Charles Marty(1)

(1) CNES, 18, Avenue E. Belin, 31401 Toulouse, France


The feasibility of the gravity field recovery employing the classical, direct numerical method has been tested. This procedure consists in cumulating normal equations, which are generated on a per orbital arc basis, and subsequent inversion using Cholesky decomposition. The estimated parameters concern both the gravity field coefficients and arc dependent ones, such as state vector at epoch and (corrections to) accelerometer calibration parameters, for example. The precision of the computation as well as the necessary CPU time have been evaluated through restitution of a high-resolution static gravity field model in absence and presence of certain other perturbations. The gravity field model coefficients have been estimated using the Satellite-to-Satellite (SST) tracking data (in this study replaced by perturbed positions) and Satellite Gravity Gradients (SGG). A data rate of 0.2 Hz, which is adequate for this first simulation, has been adopted for both data types. The simulated data were generated using the EGM96 gravity field model up to degree and order 300 while the a-priori model in the adjustment procedure was GRIM5-S1. The simulation spans two months. The relative weighting of the SST and SGG normal equations has been investigated. The comission error has been evaluated as a function of the weighting and solution strategy.


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Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry