Influence of the stop-and-hop assumption on synthetic aperture sonar imagery

Stop-and-hop (S&H) assumption is usually exploited by most multiple receiver synthetic aperture sonar (SAS) imaging geometries, which are the basis of the SAS image formation algorithms. It is a reasonable approximation for the target focusing with a slow sonar platform speed. However, it is not suitable for the systems with a fast speed at far range as this assumption would deteriorate the target focusing performances. This paper firstly analyzes the error of S&H approximation in the 2-D space domain, which shows the necessity of the compensation for this approximation error. Based on back projection (BP) algorithm, simulated data is processed with and without the S&H approximation, respectively. The experiments are carried out with two sonar platform velocities, i. e. slow and fast sonar platform velocities. The processing results further indicate that the S&H error should be compensated when the system is operated with a fast speed.