Moving Ship Velocity Estimation Using TanDEM-X Data Based on Subaperture Decomposition

In this letter, a velocity estimation method for moving ships in synthetic aperture radar (SAR) images is proposed based on a subaperture decomposition technique. In contrast to traditional methods, our method needs only a few SAR imaging parameters besides the SAR image itself. The behavior of moving ships in subaperture images is theoretically analyzed, and the ship motion parameters in azimuth direction are accurately estimated. The proposed approach was tested on real SAR stripmap images acquired by TanDEM-X, a twin satellite SAR constellation. The estimated azimuth velocities perfectly fit the data recorded by the international automatic identification system.