|REMUS-100 with broadband system installled hanging from the R/V Tioga A-frame (Peter Wiebe)|
|This image from the broadband system shows small (~6") "silver sides" in the water column. (Jonathan Fincke, Andone Lavery, Gareth Lawson, Fred Jaffre and Peter Wiebe )|
A HIGH-FREQUENCY, BROADBAND ACOUSTIC BACKSCATTERING SYSTEM FOR IMAGING, CLASSIFICATION, AND QUANTIFICATION OF WATER-COLUMN SCATTERERS FROM AUTONOMOUS VEHICLES
Andone Lavery, Gareth Lawson, Peter Wiebe, Fred Jaffre and Greg Packard
For decades, significant research effort has been directed at using high-frequency acoustic scattering techniques to remotely investigate marine organisms and small-scale fluid processes. Acoustic scattering techniques provide a rapid, high-resolution, synoptic, remote-sensing tool that complements more traditional sampling strategies such as nets and optics. Autonomous vehicles offer advantages in persistence and spatial coverage, and are expected to play a critical role in ocean observing systems. Emerging broadband scattering techniques result in increased range-resolution and spectral coverage, improving imaging, classification and quantification capabilities. A low-power, short-range, compact, autonomous, broadband (120- 1200 kHz) backscattering system appropriate for mounting on autonomous platforms has been developed. After successful tests in an estuary to image stratified turbulence, this system was recently mounted on a REMUS-100 AUV for studies of zooplankton and fish ecology. Test deployments off of Stellwagen Bank demonstrated the system is most suitable for measuring strong scattering at short ranges, and that the system was able to perform multi-mode operations of varying depths, spatial patterns, and transducer orientations, to complement data collected simultaneously with ship-board acoustic systems and traditional optical and net systems.