A new method for extracting ship motion parameters in Radarsat-2 SAR imagery

Traditionally, moving ship detection by Synthetic Aperture Radar (SAR) image is primarily based on the ship wake feature. However, many ship wakes cannot be imaged by SAR owing to changes in imaging conditions, such as the SAR band, polarisation, incident angle, and sea state. In this study, we discovered a unique phenomenon called ‘azimuth tail’ from Radarsat-2 SAR images. Following research and analysis, we determined that the azimuth tail is not manifested as a visible disturbance on sea surface waves. Instead, it is an observation enabled by certain SAR imaging principles. Consequently, we propose a new method for extracting information on moving vessels after a preliminary analysis of the principle of the azimuth tail. The results of experimental analysis of the correctness of the method indicate that the error of the vessel’s velocity from its azimuth tail is less than 20%, and the azimuth tail can be applied to the detection of moving vessels in oceans using Radarsat-2 SAR imagery.