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GOCE Gravity Field Analysis in the Framework of HPF: Operational Software System and Simulation Results

Roland Pail(1), Wolf-Dieter Schuh(3), Hamza Alkhatib(3), Christian Boxhammer(3), Christian Siemes(3), Thomas Badura(1), Barbara Lackner(1), Martin Wermuth(4), Bernhard Metzler(1), Thomas Preimesberger(1) and Eduard Hoeck(2)

(1) Graz University of Technology, Steyrergasse 30, 8010 Graz, Austria
(2) Austrian Academy of Sciences, Schmiedlstraße 6, 8042 Graz, Austria
(3) University of Bonn, Nussallee 17, 53115 Bonn, Germany
(4) Technical University Munich, Arcisstrasse 21, 8033 Munich, Germany

Abstract

In the framework of the ESA-funded project “GOCE High-level Processing Facility”, an operational hardware and software system for the scientific processing (Level 1B to Level 2) of GOCE data has been set up by the European GOCE Gravity Consortium EGG-C. One key component of this software system is the processing of a spherical harmonic Earth’s gravity field model and the corresponding full variance-covariance matrix from the precise GOCE orbit and satellite gravity gradiometry (SGG) data.

In the framework of the time-wise approach a combination of several processing strategies for the optimum exploitation of the information content of the GOCE data has been set up: The Quick-Look Gravity Field Analysis is applied to derive a fast diagnosis of the GOCE system performance and to monitor the quality of the input data. In the Core Solver processing a rigorous high-precision solution of the very large normal equation systems is derived by applying parallel processing techniques on a PC cluster.

The presentation gives an overview of the operational software system. On the basis of a realistic numerical case study, which is based on the data of an ESA GOCE end-to-end simulation, the key components of the processing architecture are presented, and several aspects of the involved functional and stochastic models are addressed.

Special emphasis is put to the filtering of the SGG observations, which is performed by means of an optimum stochastic model representing the actual noise behaviour of the GOCE gradiometer, the optimum combination of the two normal equation systems related to the precise GOCE orbit and SGG, as well as the optimum treatment of the polar gap problem by means of a regularization strategy which is tailored to this problem.

 

Workshop presentation

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