Development of a Multifrequency, Ultrasonic, Pulse-Coherent Doppler Sonar for Turbulence Studies

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

P.I. Terray (WHOI) Proposal #: 0327600 Proposal Title: Development of a Multifrequency, Ultrasonic, Pulse-Coherent Doppler Sonar for Turbulence Studies Project Summary The PIs propose to develop a small, low power, single-axis, range-gated pulse-coherent Doppler sonar module intended for boundary layer turbulence studies. This instrument will be capable of autonomous operation from a variety of platforms, such as buoys, moorings, and bottom frames, but the PIs specific interest is in using it from small autonomous underwater vehicles to estimate turbulence kinetic energy dissipation rates in bottom and surface boundary layers. The novel aspect of this work is our proposed use of multiple acoustic frequencies to reduce the bias due to Doppler phase noise in the spectrum of velocity, thereby enabling measurement of smaller dissipation rates than was previously possible with this class of sensors. The sonar developed here will be a high frequency, short range instrument, with a spatial resolution somewhat smaller than 1 cm. This sensor will also be modular so that coherent arrays and multistatic configurations can be constructed.