Passive radar using shore-based HFSWR as a non-cooperative illuminator: experimental verification and feasibility study

Passive radar has gained significant attention due to its advantages of low cost, anti-interception capabilities, and high mobility. However, research utilizing high-frequency surface wave radar (HFSWR), which possesses over-the-horizon propagation capabilities, as a non-cooperative illuminator for maritime target detection remains limited. To address this, this letter proposes a passive detection scheme using a portable receiver, exploiting an oceanographic observation HFSWR as the illuminator. The scheme employs signal processing methods including reference signal reconstruction based on Delaunay triangulation, time-domain cross-correlation synchronization, and orthogonal projection method. Experimental results demonstrate clear first-order Bragg peaks relevant to ocean surface current retrieval, as well as successful vessel detection and tracking consistent with automatic identification system (AIS) data. This work verifies the feasibility of using shore-based HFSWR as a non-cooperative illuminator for remote maritime surveillance and indicates its potential for marine environmental remote sensing.