OTH Skywave MIMO signal model and target detection in presence of multipath

HF Skywave radars exploit the refractive properties of the ionosphere to reach distances beyond the horizon allowing for the surveillance of very large areas. The instability of the ionospheric channel on wide temporal and spatial scales is one of the most important issue to be addressed in the design of such systems, especially when considering a MIMO configuration. In fact, large scale ionospheric disturbances and multipath can affect the propagating signals and degrade the radar performance. The main objective of this paper is to derive a suitable signal model that accounts for ionospheric multipath and fading. ROC curves are then simulated and compared to the case in which multipath is not considered.