Aircraft‐and satellite‐borne synthetic aperture radar images of ocean waves in orbital motions

Abstract

AbstractBecause of its all‐weather capability and high resolution, the synthetic aperture radar (SAR) is very effective for remote sensing of the ocean. However, for a moving target such as ocean waves, they affect the SAR images as a phase distortion. This paper considers the orbital motion of the ocean waves. By modeling the waves with an ensemble of the moving points, the SAR image is computed. Previously, the discussions were limited to the case of snapshot observation of the slowly moving ocean waves with a rather long wavelength by a high‐speed SAR such as that on a satellite for simplicity of the model. In this paper, this restriction is removed and the estimate and study of the SAR image become possible including a low‐speed SAR such as the one on an aircraft and waves with a short wavelength. As a result, it is pointed out that the phase velocity of the ocean waves cannot be neglected in a low‐speed SAR so that the wavelength of the SAR image is expanded or compressed and that the SAR image is strongly dependent on the ocean waves and the SAR parameters.