2025_programme: Commercial Broad Range Calibration by Multi-method Synthesis

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  • Day: June 17, Tuesday
      Location / Time: A. TERPSIHORI at 15:30-15:50
  • Last minutes changes: -
  • Session: 20. Underwater acoustic calibration, measurement, and standards
    Organiser(s): Will Slater
    Chairperson(s): Stephen Robinson, Will Slater
  • Lecture: Commercial Broad Range Calibration by Multi-method Synthesis
    Paper ID: 2350
    Author(s): Nicolas Wood
    Presenter: Nicolas Wood
    Abstract: There are a variety of challenges that come with calibrating hydrophones. One of those is that it is not possible to calibrate their full frequency range using a single test fixture. In-tank calibrations can be done down to the low-kHz range (tank size permitting) but there are many applications for which there are still several decades of frequency range of interest below that point. Open water calibrations can be done for broader frequency ranges but cost limits their application in a production environment. This paper will discuss experimentation with combining additional lab-based calibration methods to produce a synthesized calibration ranging from 1 Hz up to 200 kHz in a commercial setting. The work done compares tank-based calibrations by comparison and low frequency pistonphone measurements to comparison calibrations done using an acoustic waveguide calibration fixture and a vibrating water column apparatus. Linear and coiled waveguides were tested, with the advantage of the coiled variant being efficient use of space. Favorable results were produced in terms of achieving good agreement between the calibration fixtures in their respective frequency ranges. The projector used in this testing limited the low end of the waveguide frequency range to about 2 kHz but reaching 1 kHz or below should be possible with a more appropriate device. The vibrating water column fixture worked in the limited frequencies tested though an improved driver may permit increased useable frequency range.
  • Corresponding author: Mr Nicolas Wood
    Affiliation: Ocean Sonics
    Country: Canada

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