The work presented in this paper is part of an extensive study on HF surface wave radar, carried out jointly by ONERA and Sorbonne University for almost 20 years. In this article, we focus in particular on characterizing the maritime targets to be detected by this radar. To do this, we propose to use tools, both numerical and experimental, previously developed to characterize the radar's transmitting antennas: a numerical target model using equivalent sources, and instrumentation of a drone enabling near-field measurement of the field diffracted by the target. Finally, couplings between sky waves and surface waves on the target will be analyzed, enabling us to define a new Radar Cross Section, suitable for surface wave propagation.