RID ship imaging method based on OMFrS-WVD

Inverse synthetic aperture radar (ISAR) is a complex task to image the large-angle motion of a moving ship in a high-resolution radar system. When the sea state is in high sea conditions, the ship target sailing on the sea surface has not only the translational motion along the trajectory direction, but also the three-dimensional rotational motion. Under the influence of this high-dimensional coupled complex motion, the high-order across-range cell migration caused by the ship’s movement is more severe compared to stationary targets. ISAR imaging faces the challenges of echo high-order across-range cell migration and Doppler phase strong spatial variation, which lead to defocused images. In response to this issue, this paper proposes an OMFrS-WVD-based RID ship imaging method. By employing the proposed OMFrS-WVD time-frequency analysis processing method instead of the Fourier transform to achieve azimuthal focusing, high-resolution refocused imaging of ship targets under severe sea conditions is realized. This method avoids cross-term interference and effectively breaks through the limitations of time-frequency resolution. Theoretical analysis and simulation experimental results validate the effectiveness of the method proposed in this paper.