Fast Variance Component Estimation in GOCE Data Processing
Fast Variance Component Estimation in GOCE Data Processing
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DOI:
10.1007/978-3-642-10634-7_25
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发表时间:
2010
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影响因子:
--
通讯作者:
J. Brockmann;W. Schuh
中科院分区:
文献类型:
--
作者:
J. Brockmann;W. Schuh
For the processing of GOCE (Gravity Field and steady-state Ocean Circulation Explorer) data the program systempcgma(Preconditioned Conjugate Gradient Multiple Adjustment) was designed as a tailored solution strategy for the determination of the Earth’s gravity field in terms of a spherical harmonic analysis. Within GOCE-HPF (High Level Processing Facility) thepcgmaalgorithm works with the purpose of a tuning machine in that it is used to optimize the filter design and to determine optimal variance components with respect to the combination of satellite-to-satellite tracking (sst) data, satellite gravity gradiometry (sgg) data and additional prior information about the smoothness of the gravity field (the latter especially with regard to the polar regions).pcgmais based on an extended version of the iterative conjugate gradient (CG) algorithm, which allows for data combination in terms of observation and normal equations. A basic prerequisite for handling the nesting of the two iterative methods (variance component estimation (VCE) and parameter estimation using CG) is an efficient and fast implementation, because the VCE requires a repeated solution of the system. In this paper we will show how the nesting can be organized in an optimal way. We will concentrate on the reduction of CG iteration steps.