Frequency monitoring system for over-the-horizon radar (OTHR) in Canada

A spectral management system (SMS) is a critical component of over-the-horizon radar (OTHR), providing advice on frequency channel selection and availability for operation. The SMS comprises a frequency monitoring system (FMS) and an ionospheric condition monitoring system (ICMS). In this study, we focus on the ICMS. Because of dynamically changing ionospheric conditions, the OTHR carrier frequency needs to be adjusted regularly to maintain constant illumination of downrange targets. Methodologies are developed to determine feasible radar parameters such as operating carrier frequencies, elevation angles and azimuth angles for OTHR operation using three-dimensional ray-tracing of high frequency waves in the ionospheric medium. Ionospheric ray-tracing uses a three-dimensional electron density specification of the ionosphere. A ray-tracing technique is examined using a simulated commercial aircraft tracking exercise as a mission. The technique provides the ground range distance reached with a specific transmission frequency and elevation angle. Preliminary results suggest that the ray-tracing technique can be used to provide the basis for the way ahead in exploring OTHR applications in Canada.