Analysis of Image Domain Characteristics of Maritime Rotating Ships for Spaceborne Multichannel SAR

Ship targets are usually high-value targets, and synthetic aperture radar (SAR) moving ship indication is of great importance in maritime traffic monitoring. However, due to the motion of the ocean, maritime ships may have rotational motion in addition to the conventional translational motion. The rotational motion, including the yaw, pitch, and roll, will cause the signal characteristics of the ship to become very complex, which increases the difficulty of designing moving target indication methods. This paper studies the effect of each rotation motion on the ship’s signal characteristics in image domain for spaceborne multichannel SAR. Firstly, the range equation of an arbitrary scatterer on the ship with both rotational and translational motions is developed. Then, the influences of each rotation motion on the coefficients of the range equation and the scatterer’s along-track interferometric (ATI) phase are revealed. Finally, numerical experiments are conducted to investigate the effect of each rotation motion on the scatterer’s azimuth position shift, azimuth defocusing, azimuth sidelobe symmetry, and ATI phase, which are important parameters for moving target indication.