Application of neural networks to South African GPS TEC modelling

Habarulema, John Bosco and McKinnell, L.-A. and Cilliers, P.J. and Opperman, B. D. L. (2009) Application of neural networks to South African GPS TEC modelling. Advances in Space Research, 43 (11). pp. 1711-1720. ISSN 0273-1177

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Official URL: http://dx.doi.org/10.1016/j.asr.2008.08.020

Abstract

The propagation of radio signals in the Earth’s atmosphere is dominantly affected by the ionosphere due to its dispersive nature. Global Positioning System (GPS) data provides relevant information that leads to the derivation of total electron content (TEC) which can be considered as the ionosphere’s measure of ionisation. This paper presents part of a feasibility study for the development of a Neural Network (NN) based model for the prediction of South African GPS derived TEC. The South African GPS receiver network is operated and maintained by the Chief Directorate Surveys and Mapping (CDSM) in Cape Town, South Africa. Vertical total electron content (VTEC) was calculated for four GPS receiver stations using the Adjusted Spherical Harmonic (ASHA) model. Factors that influence TEC were then identified and used to derive input parameters for the NN. The well established factors used are seasonal variation, diurnal variation, solar activity and magnetic activity. Comparison of diurnal predicted TEC values from both the NN model and the International Reference Ionosphere (IRI-2001) with GPS TEC revealed that the IRI provides more accurate predictions than the NN model during the spring equinoxes. However, on average the NN model predicts GPS TEC more accurately than the IRI model over the GPS locations considered within South Africa.

Item Type:Article
Uncontrolled Keywords:Ionosphere; Neural networks; Accurate predictions; ASHA model; Cape Town; South Africa; Diurnal variations; Feasibility studies; Gps locations; Gps receivers; Gps tec; Input parameters; International reference ionospheres; Ionisation; Magnetic activities; Neural-network; Radio signals; Seasonal variations; Solar activities; South Africa; Spherical harmonics; TEC modelling; Total electron contents; Vertical total electron contents; Earth atmosphere; Global positioning system; Harmonic analysis; Ionospheric measurement; Planning; Resource allocation; Solar energy
Subjects:Y Unknown > Subjects to be assigned
Divisions:Faculty > Faculty of Science > Physics & Electronics
ID Code:1418
Deposited By: Mrs Eileen Shepherd
Deposited On:10 Jul 2009
Last Modified:01 Aug 2012 10:19
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