UACE2023: CHARACTERISATION OF THE PERFORMANCE OF MARINE AUTONOMOUS ACOUSTIC RECORDERS



  • Session: 02. Underwater acoustic calibration, testing, facilities and standards
    Organiser(s): Robinson Stephen, Humphrey Victor, Linné Markus, Évora Victor
  • Lecture: CHARACTERISATION OF THE PERFORMANCE OF MARINE AUTONOMOUS ACOUSTIC RECORDERS [invited]
    Paper ID: 977
    Author(s): Robinson Stephen, Ablitt Justin, Wang Lian, Linné Markus, Sigray Peter , Davidsson Per
    Presenter: Linné Markus
    Presentation type: oral
    Abstract: In recent years, there has been an increasing use of autonomous acoustic recorders for absolute in-situ measurement of sound in the marine environment. Whilst offering the enhanced ability to monitor acoustic signals autonomously for extended periods, such recorder units introduce a number of measurement and calibration challenges in addition to those associated with the calibration of individual hydrophones. These include the need to treat the autonomous acoustic recorder as a complete system, providing a traceable calibration which includes the hydrophone, hardware signal processing, the digital-to-analogue conversion, and software processing used to produce the sound data file. An additional problem can occur for recorders where the hydrophone is fixed rigidly to the end of the recorder body. In such cases, diffraction and scattering of the sound around the recorder body may influence the frequency response and directivity at kilohertz frequencies. At lower frequencies, the recorder performance may also be influenced by resonances in the recorder body. In this paper, methodologies are presented for the calibration and characterisation of autonomous recorders to determine the key acoustic performance characteristics, including the absolute system sensitivity as a function of frequency and direction. Consideration is given to effects due to the proximity of the recorder body to the measuring hydrophone on the frequency and directional response of the overall system. Examples of the results obtained are given and a discussion is presented of the implications of system performance on the quality of the measured data.
  • Corresponding author: Dr Linné Markus
    Affiliation: FOI
    Country: Sweden
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