Multi-grazing ISAR for side-view imaging with improved cross-range resolution

The use of multiple radar systems, carried by a set of air platforms flying in formation, is demonstrated to be able to provide side-view ISAR images of pitching and rolling targets with increased cross-range resolution. The multi-grazing ISAR technique is devised for two different cases: (i) multistatic case with a single platform carrying an active radar and the remaining equipped with receiving only devices, (ii) MIMO case with each platform carrying an active radar. The needed focusing technique is presented with the results obtained against simulated ISAR data; the performance analysis shows that the proposed technique is able to provide an increase of the cross-range resolution up to the number of radar systems in the multistatic case or even higher in the MIMO case. The multi-grazing ISAR is especially suitable for the application to ship target imaging in the presence of low sea state giving rise to side-views of poor quality when imaged with conventional ISAR.