ISAR Imaging for Moving Targets with Large Rotational Angle

Wideband radar can get high range resolution. In order to obtain high azimuth resolution, a large rotation angle of moving targets relative to the radar line of sight is required. As the migration of scatterers in different range resolution cells is different, range alignment cannot compensate it completely. When the rotation angle of the moving target is large, the migration through resolution cell (MTRC) will occur obviously, which results in great image resolution degradation. A new ISAR imaging algorithm is proposed in this paper to solve the problem. In the proposed algorithm, the process of large-angle high-resolution imaging is divided into several small-angle low-resolution imaging processes. Then after image scaling, image rotation, image translation, inverse process of ISAR imaging, data splicing and re-ISAR imaging, high resolution image will be produced. Theoretical analysis and simulations show that the proposed algorithm can compensate the MTRC of scatterers and obtain high-resolution images.