Deployment of wideband bio-inspired sonars for autonomous underwater operations

Recent developments in the understanding and application of wideband bio-inspired acoustic sensors are enabling new applications of autonomous underwater vehicles (AUVs) for security and oilfield use. Appropriate use of wideband signals has enabled improved discrimination between natural and man-made objects that have physically similar appearance, as well as the detection of buried and partially buried objects. Wideband sonar developments in the Ocean Systems Laboratory at Heriot-Watt University have focused on prototypes based on the bottlenose dolphin sonar, covering a frequency band from around 30 to 150 kHz and having a frequency dependent beam-width that is, considerably larger than conventional imaging sonars. In parallel, AUV technology has developed to allow much greater levels of autonomy in allowable vehicle behavior. New generations of vehicle have moved beyond switching of pre-programmed scripts (behaviors) and their parameters, to systems that interleave planning and execution at a fine grain, or can re-plan mission sections on the fly in response to unexpected events. Combining this improved sensor performance with increased autonomy has enabled a first generation of fielded system to act responsively in tasks such as tracking and inspection of proud or buried cables, and the detection and characterization of mines, beyond being mine like objects. Second generation systems that use their autonomy to optimally take multiple looks and control the spectral content of pings in an environmentally adaptable way are under consideration.