Quantifying Seabed Properties in Shelf Waters Using a Parametric Sonar

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Authors
  1. Hines, P.C.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
Defence Research Establishment Atlantic is developing a bottom-tethered, wide-band sonar for collecting acoustic data in the open ocean. The transmitter, a parametric array, offers three advantages: a wide bandwidth (1-10 kHz), a narrow beamwidth (approximately equal to 3 degree) and virtually no sidelobes. These features allow direct measurement of seabed parameters in shallow water. Direct in this context means the absence of complications resulting from unwanted interactions of the acoustic pulse with ocean boundaries. This makes the parametric sonar an ideal tool with which to interrogate the seabed in shelf waters and quantify several geo-acoustic properties. To complement the narrow-beam active sonar, a six-channel superdirective/intensity array has been developed for the receiver. The superdirective receiver obtains a significantly narrower beam for a given array aperture than that obtained using a conventional acoustic receiver. A 900 MHz rf command link is used to steer the array to any combination of azimuth and tilt angle. Together with control over azimuth and tilt angle, the sonar frame is instrumented to monitor depth, roll and vertical acceleration to ensure quality control of the data. Data transmission back to the ship is accomplished via a 2.3 GHz rf data link capable of a data-transfer rate of up to 8 Mbits s1(-). TRUNCATED
Keywords
Parametric sonar;Environmental acoustic data;Parametric arrays;WBS (WideBand Sonar);Acoustic intensity;Acoustic pressure;Superdirective arrays;Intensity arrays
Report Number
DREA-SL-1999-045 — Reprint
Date of publication
01 Apr 1999
Number of Pages
10
Reprinted from
Meas. Sci. Technol, vol 10, 1999, p 1127-1134
DSTKIM No
CA001410
CANDIS No
513110
Format(s):
Hardcopy;Document Image stored on Optical Disk

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