FEASIBILITY OF BUILDING AN INEXPENSIVE DOPPLER SPEEDOMETER FOR USE IN SHALLOW WATER

A single, inexpensive acoustic transducer with a fairly wide beamwidth has been successfully used to measure the Doppler frequency spectrum of the backscattering of an acoustic signal off of a rough surface. The maximum Doppler shift is proportional to the transducer's true speed. The transducer, with a resonant frequency of 200 kHz and a beamwidth of about 50 degrees, was towed in the MIT Ship Model Towing Tank at several speeds. Actual results are in good agreement with the predicted results. The present acoustic speedometers, consisting of two or four sets of four transducers in a Janus configuration and using narrow width beam patterns to minimize the frequency spread about the maximum Doppler shift, are expensive. The use of a less expensive speedometer with one transducer as a viable alternative to the existing speedometers, especially by small-boat owners, appears to be quite feasible.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  USA  02139
  • Authors:
    • Cater, J E
  • Publication Date: 1974-5

Subject/Index Terms

Filing Info

  • Accession Number: 00057477
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Report/Paper Numbers: MS Thesis
  • Files: TRIS
  • Created Date: Aug 28 1974 12:00AM