Quantifying ionospheric impact on GNSS users and developing ionospheric warning system for middle and high latitude region

An approach to quantify ionospheric impact on GNSS users in the high latitude region is developed and proposed in this thesis. The ionosphere shows extreme variability in this region with multiple impacts in terms of large gradients and absolute values of ionospheric delay, e.g. Storm Enhanced Density (SED). In this work positioning errors during such disturbed ionospheric periods are predicted by deriving ionospheric vertical TEC maps (VTEC) using raw observations from ground-based GPS reference stations and estimating the absolute magnitude of ionospheric VTEC and gradients in VTEC. The performance of the prediction system is evaluated through comparisons with truth position estimates for cases of single frequency, DGPS and WAAS users. It is observed that the proposed system better matches the true spatial distribution of positioning errors. As there is no ionospheric prediction service in Canada specific to GNSS users, under rigorous testing this product could be augmented with other prediction indices and broadcast to the existing GNSS users. Timely warnings may be issued for safe operation of various land and marine navigation applications.