A Canadian Ionospheric Warning and Alert System

Mahmoud El-Gizawy and Susan Skone

Abstract:	Auroral activity is a significant concern for reliable operation of GPS positioning applications at high latitudes. Auroral substorms are characterized by increased spatial and temporal decorrelations of ionospheric range delay, and loss of signal availability can occur during periods of ionospheric scintillations – a major concern during the current period of solar maximum. In recent years, GPS precise positioning applications have been disrupted consistently in Northern Canada – at significant cost to commercial surveying operations. In order to mitigate the economic impact of such effects, surveyors have developed methods of determining the nature of ionospheric activity in localized regions. For example, magnetometers have been installed in survey sites to monitor local magnetic field variations in real-time and detect the presence of auroral activity. Such methods have proven adequate, but far from ideal. Given the number of GIS, exploration, and construction applications presently relying on GPS in Canada, a significant need exists to develop ionospheric warnings and alerts for the GPS user community. In order to provide timely predictions of auroral activity, and associated degradations in receiver tracking performance and positioning accuracies, we are currently developing a real-time ionospheric warning and alert system for GPS users in Canada. This system will be based on a network of at least three GPS Ionospheric Scintillation Monitors (GISM) which provide real-time scintillation parameters extracted from 50 HZ L1 phase observations, in addition to raw GPS code and phase observations, rates of change of total electron content (TEC), and absolute TEC values. Observations will be processed at a centralized control facility at the University of Calgary. The focus of this research is the development of methods to track the magnitude and extent of ionospheric effects in Canada and Northern United States. Measures of associated impacts on GPS applications will be provided to GPS users in near real-time. It is intended that GPS users will access the real-time ionosphere warning service via the internet. This paper describes preliminary development of the system and methodologies. Initial results indicate that such a service may provide significant benefit for GPS users.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	1345 - 1352
Cite this article:	El-Gizawy, Mahmoud, Skone, Susan, "A Canadian Ionospheric Warning and Alert System," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 1345-1352.
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