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Polarimetric mapping of ship wakes

This paper addresses the problem of ship wake detection and analysis at low grazing angles. specifically, we examine the spatial distribution of the characteristic polarimetric signatures of the sea surface in and around the wakes of a pilot boat. The received signals were range-processed and polarimetrically decomposed to yield the characteristic polarisation states. Inspection of the locations of these states revealed that the polarisation signatures were highly non-uniformly distributed in the spatial domain, as expected, with interesting features attributable to nonlinear effects. Focusing on the cross-polar nulls, we found that the corresponding eigenvector distribution made a strong transition as one moved from the wake region to the surrounding sea. By defining appropriate scalar quantities we were able to identify wake and clutter regions. The results suggest that exploitation of the coherent polarisation domain may significantly enhance wake feature extraction and discrimination.