Characterizing the Impact of Ionospheric Wave Structures on Coordinate Registration.

ABSTRACT: We propose the assembly of a coordinate registration assessment suite applicable to over-the-horizon radar (OTHR). The suite includes a 3-D ionospheric model coupled with a 3-D magneto-ionic ray tracing code. The propagation model will have sufficient fidelity to accurately capture the effects of atmospheric gravity waves down to the high frequency limit. The propagation model will be designed to populate OTHR coordinate transform data for examination of the impacts of travelling ionospheric disturbances (TIDs). The suite builds on a parametric climatological model, and be capable of ingesting data from a range of sensors (sounders, GPS) and for a range of TID scale variations that will be formulated as part of this proposal. The impact of TIDs will be assessed over a range of different TID conditions (directional spectrum) and OTHR operating scenarios to assess the nature of TID activity most relevant to OTHR accuracy. We propose developing high level design for a measurement system capable of providing real time estimates of TIDs in a format relevant for the propagation model. The design is expected to utilize modern direct digital multi-channel HF hardware that can provide high fidelity characterization of TIDs at relatively low cost. BENEFIT: The system is aimed at improving the accuracy of HF geolocation systems. A cost effective TID measurement network providing executable input to an advanced coordinate registration system would take the accuracy of systems such as Next Generation OTHR and HF Emitter Geolocators to new levels of accuracy. Recent interest in Next Generation OTHR within the Department of Defense, specifically applied to a NORAD/NORTHCOM homeland defense mission, provides incentive to invest in developing this technology.