High-Resolution Sea Surface Current Vector Field Inversion Based on Circular Scanning SAR.

The Doppler scatterometer is an instrument used in real aperture radar in conjunction with a circular scanning antenna and has wide swath and multiangle characteristics. Many scholars have studied sea surface current vector field based on the use of the Doppler scatterometer. However, the existing methods directly use the phase difference of the spectrometer's echo to obtain the current vector field, and the resolution can be improved. This study proposes a high-resolution inversion method for ocean surface current fields based on circular scanning synthetic aperture radar (SAR). The current field is estimated by the proposed method based on the Doppler spectrum of the single complex image to realize high-resolution current vector field inversion. The current field inversion of circular scanning SAR is very sensitive to attitude and wind field errors. Accordingly, a model is established to study the influences of the main errors on Doppler shift estimation, and a global optimization method is proposed to realize high-precision current velocity inversion and synchronous error estimation. The effectiveness of this method is verified by using airborne circular scanning SAR data.