| In order to provide timely predictions of the auroral activity, and associated degradations in receiver tracking performance and positioning accuracies, a monitoring technique of the magnitude and extent of the ionospheric effects in Canada and Northern United States is developed. In addition, a real-time ionospheric warning and alert system for GPS users is established. The techniques presented here are based on dual frequency GPS observations from a network of permanent GPS reference sites in North America, using measurements from IGS network. Using dual-frequency measurements, a GPS-based index is introduced to describe the local ionospheric activity in the region where the observation line-of-sight penetrates the ionosphere. Statistical analysis is conducted to define the threshold values of the introduced index, and to define the corresponding spatial and temporal correlations of TEC. Regions of high, moderate, and quiet ionospheric activity are identified according to the GPS-based index. A warning, therefore, is issued according to the user's location.;It is intended that techniques developed in this thesis will be applied in the Canadian GPS Network for Ionosphere Monitoring (CANGIM)---currently being developed by the University of Calgary. This network will consist of a number of GPS Ionospheric Scintillation Monitors (GISM). Observations will be processed at a centralized control facility at the University of Calgary. It is intended that GPS users will access the real-time ionosphere waming service via the Internet. (Abstract shortened by UMI.)... |
