Small scale test bed for studying multiaspect and multistatic sonar systems.

Abstract

A nominally 1:50 scale acoustic test bed is operational at the Naval Surface Warfare Center‐Panama City Division (NSWC‐PCD) to image free‐field, bottom, and buried targets using multiaspect, bistatic, backscatter, forward scatter, and synthetic aperture sonar (SAS) techniques. The test bed is designed to test and study novel geometries and techniques faster and cheaper than can be done in the field. Using precise translational positioning systems mitigates any issues associated with positioning of multiple sonar platforms in the field. The use of two transmit and receive transducer platforms is superior to a single platform, which is restricted to purely backscattered imaging, for producing SAS images. With two platforms, one can generate four images, two using backscattered return data and two using data sent from one platform to the other. Thus, the system is inherently both dual aspect and bistatic. The setup, including the scaled sediment, acoustic sources and receivers, and computer controlled translational stages, is described. Preliminary beamformed data are presented showing the relationships between each of the images described above. In addition, techniques to mitigate the interference of direct path returns in forward‐scattering geometries are discussed. [Work sponsored by the Office of Naval Research.]