Empirical model in the characterization of high frequency propagation in the Arctic region
University of New Brunswick
The use of high frequency (HF) communication at high latitudes still forms the backbone of many systems, owing to the fact that there are few alternatives to HF radio for the merchant and fishing fleets, military forces (land, sea and air) and for the civil aviation industry for these latitudes. HF communication uses the ionosphere as a medium of propagation, but its variable nature can be a disadvantage to both the radio operators and users. The choice of a suitable usable frequency is thus dependent on the ability to predict the conditions of the ionosphere. Thus, HF propagation predictions can be inferred from the predicted conditions of the ionosphere. In fact, in most cases, the predictions of ionospheric conditions and HF propagation are often assumed to be identical. Hence, the need to develop ionospheric model(s) suitable for high latitudes to enable a relatively smooth operation of ionospheric-dependent radio communication. Most of the available models, particularly the empirical ones were developed with little data at high latitudes. Data availability has improved over the years due to technological advancement and continued research. For instance, the Canadian High Arctic Ionospheric Network (CHAIN) provides a wealth of data for the polar and auroral regions. Using CHAIN data, the performance of the Voice of America Coverage Analysis Program (VOACAP), Ionospheric Communication Enhanced Profile Analysis and Circuit (ICEPAC) and the recommendation 533 (REC533) propagation models was evaluated and some inconsistences were identified for each of the models. An additional study of ionospheric variability in the arctic region revealed that the currently available International Telecommunication Union Recommendation (ITU-R) variability factors demonstrate notable differences from observations during the winter and equinoxes. A model for the critical frequency of the F2 layer was developed using both CHAIN and Space Physics Interactive Data Resource (SPIDR) data. The model results show an improvement compared to the available baseline International Reference Ionosphere (IRI) model.