Title page for ETD etd-12052011-230747


Document Type Master's Dissertation
Author Van der Merwe, Stefanus Jansen
Email sj@vandermerwe.info
URN etd-12052011-230747
Document Title Characterisation of the ionosphere over the South Atlantic Anomaly by using a ship-based dual-frequency GPS receiver
Degree MEng
Department Electrical, Electronic and Computer Engineering
Supervisor
Advisor Name Title
Dr P Cilliers Committee Chair
Dr P de Villiers Committee Co-Chair
Keywords
  • mobile dual-frequency GPS
  • total electron content
  • high frequency communications
  • tomography
  • South Atlantic Anomaly
  • electron density
  • ionosphere
Date 2012-04-23
Availability unrestricted
Abstract
The ionosphere is a layer of ionised gas in the upper layers of the atmosphere around the Earth that plays a critical role in satellite communication, military communication and space science. The influence that the ionosphere has on communication systems can be quantified if the distribution of the electron density within the ionosphere is known. Several methods and instruments to determine the distribution of electron density are currently being used: satellites, ionosondes, incoherent scatter radars and computerised ionospheric tomography based on dual-frequency GPS signals. The present study investigates a novel way of using GPS receivers on mobile platforms to achieve near real-time ionospheric characterisation over locations beyond the reach of land-based ionospheric characterisation methods. GPS observations were collected, pre-processed and inverted by means of tomography to generate three-dimensional electron density maps. These electron density maps were analysed and verified. The viability of using observations from a mobile GPS receiver for ionospheric tomography was investigated. The algorithms were verified by means of a model ionosphere and a simulated GPS receiver. Furthermore, electron density maps generated from GPS observables from a mobile receiver were verified against ionosonde-derived electron density profiles, static land-based GPS receivers and known high-frequency propagation paths using propagation path prediction. The results were evaluated and the conclusion was that, although some aspects still have to be addressed, a dual-frequency GPS receiver on a ship can provide useful ionospheric characterisation in areas which are otherwise poorly or not covered by land-based receivers.

2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Van der Merwe, SJ 2011, Characterisation of the ionosphere over the South Atlantic Anomaly by using a ship-based dual-frequency GPS receiver, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-12052011-230747 / >

E12/4/89/gm

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