Estimation of Azimuth and Range Velocity of Detected Vessels from SAR Image using Doppler Frequency Characters

This study presented an effective algorithm that measures target azimuth and range velocity of vessels in SAR image without assistance of AIS information. As the SAR Doppler history was modified from target velocity, azimuth and range velocity caused the target to be defocused and shifted, respectively. The proposed algorithm utilized phase refocusing function and sub-aperture analysis which calibrated the distortions and accordingly derived two-dimensional velocity of the target in a precise manner.