On The Degree of Polarisation of a Fishing Trawler under SAR Incidence Angle Diversity

In this study, the L-band polarimetric scattering of a fishing trawler is investigated with respect to the synthetic aperture radar incidence angle. This unique opportunity is explored using a time series of airborne uninhabited aerial vehicle synthetic aperture radar imagery where the same small fishing trawler is observed under a broad range of incidence angles, spanning from about 35° up to 55°. The degree of polarization and its polarization signature are extracted from the synthetic aperture radar data set to evaluate the L-band polarimetric scattering of the ship target under analysis, with emphasis on the changes in the ship scattering associated with the polarized part of the backscattered signal. Furthermore, changes in the dynamic of the degree of polarisation signature over the fishing trawler and a reference target-free sea surface area are analyzed quantitatively, showing that the polarized component of the L-band signal scattered off sea and ship is significantly sensitive to the acquisition geometry, i. e., the synthetic aperture radar incidence angle.