A Fourier-based motion estimation approach for wide band synthetic aperture sonar

Synthetic aperture processing could improve the azimuth resolution of sonar images. Nevertheless, the sonar motion yields to phase errors which prevent this accurate processing. The aim of the authors' study is to correct sub-wavelength phase errors, due to the sway, for the detection and classification of targets lying on the seafloor. They present a Fourier-based motion compensation approach: the phase error modelization and the motion compensation processing are developed in the Fourier domain, like the whole synthetic aperture inversion. This approach is suited for wide-band signals. Experimental results show the effectiveness of the approach and its limitations.