Research on phase compensating factor of chirp scaling algorithm in multiple-receiver synthetic aperture sonar

Abstract

Synthetic aperture sonar (SAS) imaging with multiple-receiver techniques can obtain high mapping rate and high azimuth resolution synchronously, however, it might also lead to a complexity of algorithm processing. Regarding the multi-receiver SAS imaging processing, conventional CS algorithm might cause serious defocusing of targets in the edge of the swath due to the relatively large approximate error in the phase of an echo signal. A two-dimensional spectral expression of multi-receiver SAS echoes was studied. From the perspective of phase compensation, the multi-receiver synthetic aperture processing was divided into multi-receiver sonar phase compensation and single receiver sonar phase compensation based on a CS algorithm. Then a high-order Taylor expansion of echo phase was obtained and a three-order or above phase compensating factor for phase compensation was adopted to improve compensation accuracy. The simulation results showed that the algorithm presented in this paper has higher azimuth resolution than the traditional algorithm, and both the center point targets and the edge point targets in the swath have better focus, which can meet the requirements of multi-receiver SAS imaging.