DOA Estimation Using Shipborne HFSWR Based on Virtual Synthetic Array

Shipborne high-frequency surface wave radar (HFSWR) is a favored trend, due to its advantages of extended detection area and maneuverability. However, the limitations of the platform size present a challenging problem of poor azimuth resolution. To address this issue, the synthetic aperture technique is applied to shipborne HFSWR, and a new direction-of-arrival (DOA) estimation method based on synthetic virtual array is proposed in this paper. First, the digital beamforming algorithm of a uniform line array is presented and the synthetic aperture scheme of shipborne HFSWR was illustrated. Then, the signal model of the single-element synthetic virtual array is built, which is based on the motion of the radar relative target. Finally, for the multi-element situation, the compensation of the phase correction factor is the key of synthesis virtual array. The numerical simulation verifies that the proposed method can improve the DOA estimation performance effectively in shipborne HFSWR.