Ship Velocity Automatic Estimation Method Via Two-Dimensional Spectrum Pattern of Kelvin Wakes in SAR Images

In this article, an automatic method is proposed for ship velocity estimation based on the two-dimensional spectrum pattern of Kelvin wakes in synthetic aperture radar (SAR) images of which the effectiveness is proved with both simulation and experimental results. The proposed method has the following advantages. First, the velocity can be estimated automatically, which will not introduce extra error caused by manual operations. Second, the prior knowledge of SAR parameters is not needed and the only factor that matters is the pixel spacing of the SAR image. Then, the effects of ship speed, wind speed, the angle between ship heading, and SAR platform flight direction on the spectrum of Kelvin wakes, and the ability of the proposed method are studied. It is found that ship velocity can be estimated precisely with the proposed spectrum-based method with a larger ship speed or a low wind speed. In addition, it is easier to estimate ship speed when the SAR platform flies across the ship heading.