Data-Driven Autocalibration for Swath Sonars

Abstract

Sidelobes in swath sonar water column imagery can obscure targets of interest and create erroneous bottom detections. Differences between ideal and actual element responses limit the achievable sidelobe level for practical arrays. Therefore, removing or reducing the errors by calibration may reduce the sidelobe level. We examine an autocalibration technique for swath sonars that use data collected while mapping. Our method is based on the generalized interferometric array response (GIAR). The GIAR values are used to find pointlike signals and maximized to estimate the amplitude and phase errors for each element. On simulated data, this reduces the sidelobe level to below −