Williamson and Associates Inc.

Seattle, WA, United States

Williamson and Associates Inc.

Seattle, WA, United States

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Larsen L.J.,SL Hydrospheric LLC | Wilby A.,Applied Signal Technology | Stewart C.,Williamson and Associates Inc.
MTS/IEEE Seattle, OCEANS 2010 | Year: 2010

Deep ocean towed surveying is an ideal application for synthetic aperture sonar (SAS). The towed platforms move slowly to maintain operational depth. Operational frequencies are necessarily low to provide adequate coverage range, yet the desire for improved resolution at range demands longer arrays. A new 60kHz SAS system employing a three stave interferometric swath bathymetry component is presented. The bathymetric data are analyzed for performance and compared with International Hydrographic Organization (IHO) standards. Explanations of an optional Synthetic Aperture Interferometric Bathymetry processing package are undertaken showing increased data density which by filtering to produce a decimated set provides lower apparent noise from multiple scatterers. Low frequency, high resolution SAS systems will have area coverage rates comparable to conventional sidescan sonars but will provide resolution that is hard to match, even with the highest frequency survey grade conventional sidescans. A brief discussion examines some benefits of SAS in this regard. Recent surveys for buried cables and wreck searches have revealed the benefits of using lower frequency sidescan sonars. The low frequencies penetrate bottom surface layers of thin sediment to identify plow hazards and search objects while higher frequency systems reflect off of the water-sediment acoustic interface to present imagery devoid of harder material actually present. ©2010 IEEE.


Wright A.St.C.,Williamson and Associates Inc.
MTS/IEEE Seattle, OCEANS 2010 | Year: 2010

The advantages of collecting seafloor imagery, bathymetry and subbottom profiler data from 6000 meter rated deeptowed sidescan sonar systems has been appreciated for many years. The number of systems in active use in the commercial, scientific, and government communities continues to increase. New improvements to these systems include additional subsystems such as gap-filler sonars, integrated CTD's, and improved positioning equipment; enhanced image and data processing software; and additional swath bathymetry and synthetic aperture capabilities. Countries with organizations supporting these sonars include the United States, United Kingdom, Russia, France and Japan. This presentation will describe rationale and operating procedures for these sonars and briefly summarize the recent operations of the various systems. ©2010 IEEE.

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