Shipborne HF EMVS: RD-Domain Virtual Aperture Generation for Resolution Enhancement

Autonomous surface vehicles (ASVs), as a novel type of shipborne platform system, are widely used for ocean monitoring. In a shore-transmit/ship-receive bistatic system, the detection range of shore-based high-frequency surface wave radar (HFSWR) can be greatly extended. However, the limited space on the ship restricts the antenna aperture, thus degrading the angular accuracy of the shipborne radar. An electromagnetic vector sensor (EMVS) estimates target angles by measuring the electromagnetic vector information of the incident wave, and its small physical size makes it well suited for shipborne platform. Nevertheless, a single EMVS offers limited angular resolution and may fail to separate closely spaced targets. To overcome this, we propose a coarse-to-fine range-Doppler domain aperture generation (CFRDAG) strategy that exploits ASV motion to turn a single EMVS into a virtual EMVS array, thereby enlarging the effective aperture and improving ASV-radar resolution.