Advances in Research on the Impacts of Tropospheric Over-the-Horizon Propagation on Radar Emitter Signatures

Tropospheric over-the-horizon (OTH) propagation is a prominent research hotspot in the field of radar countermeasure and reconnaissance. Clarifying the variation law of its impacts on radar emitter signatures is the critical prerequisite for over-the-horizon radar emitter recognition (RER) in complex electromagnetic environments. In recent years, the relevant theories and practical applications of tropospheric OTH propagation mechanism and RER have been continuously improved. However, existing studies have not yet achieved in-depth integration of the two fields, nor systematically sorted out the influence mechanism and variation law of OTH propagation on radar emitter signatures. On this basis, this paper starts from the mechanism and models of tropospheric OTH propagation, conducts the analysis of emitter signal characteristics through the channel characteristics of propagation, and systematically reviews the research achievements in this field. Finally, this paper summarizes the technical bottlenecks and improvement strategies for RER in OTH scenarios, and aims to provide a theoretical and technical reference for promoting the integration of OTH transmission and RER technologies.