A synthetic aperture parametric sonar for buried object detection

Abstract

This paper describes an experimental comparison between a parametric sonar and a conventional sonar for the detection of small objects on the seabed. First, a quick description of the parametric sonar used is given. Second, rail and sea experiments are described. The parametric array was mounted on a rail which was able to move at a constant speed (0.25 m/s). As a first experiment the sonar was kept fixed on the rail. A comparison of the detection of the object put on the seabed is performed between conventional sonar and the parametric one. The obtained results show a great improvement brought on by the parametric sonar which is less affected by bottom reverberation and which allows very precise identification of the detected object. As a second experiment, the sonar was moving on the rail in order to be able to perform synthetic aperture sonar processing with the parametric array. Significant improvements in resolution and signal-to-noise ratio were obtained when integrating together successive pings transmitted while the sonar was moving. In addition, a similar experiment performed at sea with a towed fish is described and results are given.