Multi-domain RD data exploitation for improving spatial sensing of USV-borne MIMOHFSWR

To meet the demand for high mobility, compact platforms such as unmanned surface vehicles (USVs) have been widely adopted. However, their limited size restricts the physical aperture of onboard radar, leading to degraded angular resolution. Conventional aperture-extension techniques, which rely on direct processing of target echoes, fail in high-frequency surface wave radar (HFSWR) scenarios where target returns are dominated by strong non-target components. Moreover, these methods typically exploit only single-domain information, leading to incomplete utilization of the echo data. To overcome these limitations, we propose a novel virtual aperture extension method based on Multi‑Domain data Exploitation in the range‑Doppler Domain (MDE‑RD) for USV‑borne MIMO-HFSWR, aimed at enhancing the system’s spatial sensing capability. The proposed method first performs aperture synthesis in the RD domain, where target signals can be isolated from dominant clutter and interference, thereby overcoming the fundamental limitation of conventional techniques. It then jointly exploits the multi‑domain information—temporal, spatial, and signal—extracted from the target's RD cell to generate a larger virtual aperture than single‑domain processing allows. Simulation and experimental results validate the proposed MDE‑RD approach, demonstrating its significant improvement in angular estimation and resolution accuracy for USV-borne HFSWR, thereby advancing radar spatial sensing capabilities in complex ocean environments.