Radar Imaging of Nonstationary Rotating Ship Target With GEO-Shipborne Bistatic Configuration

Geosynchronous satellite (GEO) synthetic aperture radar (SAR) has a number of advantages in marine surveillance due to the global-scale coverage and strong anti-strike capability. However, ship imaging represents a challenge for SAR systems, as it has nonstationary 3-D rotations induced by irregular ocean waves, which produces evident image defocusing. In order to overcome such a problem, a novel kind of bistatic inverse synthetic aperture radar (ISAR) configuration, named GEO-shipborne bistatic ISAR, is presented. In this paper, the receiver signal model of GEO-Shipborne bistatic ISAR configuration is derived when the target and the receiver ship both have 3-D nonstationary rotations. On the basis of the proposed model, an analysis of imaging aliasing induced by receiver ship’s rotations and GEO transmitter’s orbital motion on the obtained images is given and compensation algorithms are discussed. Then, a novel algorithm of GEO-Shipborne bistatic ISAR imaging in combination with the modified cubic phase function (MCPF) is proposed. Simulation results validate the correctness of the proposed model and the effectiveness of the novel algorithm proposed for GEO-Shipborne bistatic ISAR configuration.