Improved Frequency Monitoring System for Sky-Wave Over-the-Horizon Radar in Canada

Sky-wave over-the-horizon radar (OTHR) systems are of particular interest to the Canadian Department of National Defence (DND) since they provide the potential for surveillance of Canada. Because of dynamic ionospheric conditions in polar regions, any OTHR would necessitate a system where the operating frequencies and elevation angles change periodically to maintain constant detection of targets downrange. In this regard, an accurate electron density model is necessary for the purpose of improving operational OTHR and OTHR planning/design. Recently, the first phase of the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) was released, which was funded under the Defence Research and Development Canada's (DRDC) All Domain Situational Awareness (ADSA) program. In this letter, the E-CHAIM is used to determine the feasible radar parameters such as operating frequencies and elevation angles by a 3-D ray-tracing technique. The results will help to form the basis of the frequency monitoring systems (FMS) that will control these polar OTHR systems.

I. Introduction

Sky-wave over-the-horizon radar (OTHR) systems operate in the high-frequency (HF) band of 3–30 MHz and use radio-wave ionospheric refraction to detect targets at ranges up to 3500–4000 km, considerably further than the horizon line. These systems are generally situated inland and are best suited to detect fast-moving air targets [1]. Due to their large detection ranges, sky-wave OTHR systems are of particular interest to the Canadian Department of National Defence (DND) to monitor Canada’s north.