Multiple experimental investigations into buried mines detection and classification with SAS

Buried mines are a serious threat against harbor protection and littoral warfare. Several ways have been proposed to detect buried mines: parametric sonars, magnetic gradiometers and low frequency synthetic aperture sonars (LF SAS). To validate the last technique, two experiments have been conducted by GESMA of France using rail facilities, one at the Bay of Brest in December 1999 and one in Singapore area, with DSO of Singapore, in August 2000. For the first experiment, the seabed is typified with decomposed shells and algae, and for the second experiment, the seabed is a mud-silt bottom with nonhomogenous sedimentary deposits that may bury mine targets. Both experiments are in very shallow water conditions and frequency investigations are running from 14-80 kHz. To study the impact on SAS operation in such an environment, relevant and real data must be used for analysis to assess the sonar and processing performances. Experiments designs, approaches and preliminary results are described in this paper