Tomographic reconstruction of the ionospheric electron density as a function of space and time

Date
2009
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Source Title
Advances in Space Research
Print ISSN
0273-1177
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ELSEVIER
Volume
43
Issue
11
Pages
1702 - 1710
Language
English
Type
Article
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Abstract

Electron density distribution is the major determining parameter of the ionosphere. Computerized Ionospheric Tomography (CIT) is a method to reconstruct ionospheric electron density image by computing Total Electron Content (TEC) values from the recorded Global Positioning Satellite System (GPS) signals. Due to the multi-scale variability of the ionosphere and inherent biases and errors in the computation of TEC, CIT constitutes an underdetermined ill-posed inverse problem. In this study, a novel Singular Value Decomposition (SVD) based CIT reconstruction technique is proposed for the imaging of electron density in both space (latitude, longitude, altitude) and time. The underlying model is obtained from International Reference Ionosphere (IRI) and the necessary measurements are obtained from earth based and satellite based GPS recordings. Based on the IRI-2007 model, a basis is formed by SVD for the required location and the time of interest. Selecting the first few basis vectors corresponding to the most significant singular values, the 3-D CIT is formulated as a weighted least squares estimation problem of the basis coefficients. By providing significant regularization to the tomographic inversion problem with limited projections, the proposed technique provides robust and reliable 3-D reconstructions of ionospheric electron density.

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Keywords
Computerized ionospheric tomography (CIT), Ground positioning satellites (GPS), Ionosphere, Ionospheric reconstruction, Occultation data, Singular value decomposition (SVD), Voxelization
Citation
Published Version (Please cite this version)