EXPERIMENTS WITH A SHIP-MOUNTED LOW FREQUENCY SAS FOR THE DETECTION OF BURIED OBJECTS.

In September 2002, GESMA and TNO-FEL carried out a sea trial with a low frequency (20 kHz) sonar mounted on a mine hunter. The objective of the experiments was to collect sonar echoes from proud and buried objects for subsequent synthetic aperture processing. A large data set was collected, consisting of sonar data from several SAS modes and relevant non-acoustic measurements such as sonar movement from a Motion Reference Unit, GPS data, ship navigation data and sound speed measurements. Inspection by divers, a scan of the trial areas with a high-frequency side scan sonar and bottom core analysis completed the data collection. This paper presents details of the experiments and some preliminary results. The use of a ship-mounted sonar has proven quite valuable. The ship is sufficiently stable for SAS applications and a wide variety of non-acoustic sensors is available for improving the SAS processing.