Extending the capabilities of synthetic aperture sonars (multiaspect and multiband) in the overall objective of buried mines classification

Abstract

Low- and medium-frequency sonars are more adequate for long-range detection and classification operations needed for mine hunting. In addition, with low frequencies the acoustic waves can penetrate into the sediment. With such a technique, detection of buried mines is possible. But, in real conditions, at sea, the number of alarms and false alarms is important. One of the problems is to find solutions to reduce those false alarms. One technique developed in this presentation is the multiband technique in association with large-bandwidth acoustical arrays. The aim of this technique is to reduce the speckle effect with noncoherent summation of multiband coherent SAS images. This technique has been focused, at the moment, on mines laying on the seabed, and is expected to be used on buried mines. The second technique discussed in the presentation is the multiaspect SAS processing applied in the low-frequency case for buried mines detection and classification. This technique is intended to help during the echo classification process of buried mines, limiting the false-alarm rate and reconstructing the shape of the object by following the echo along the shape of the objects.