Application of seafloor backscattering strength estimators to echosounder measurements at sea

Irène Mopin, Gilles Le Chenadec, Michel Legris, Philippe Blondel, Jacques Marchal, Benoît Zerr

Research output: Contribution to conferenceAbstractpeer-review

Abstract

Echosounders are ubiquitously used to measure bathymetry; they can also provide seabed reflectivity maps based on the measurement of the seafloor acoustic response and its variations. For each ping and beam, the backscattering strength BS is estimated and associated to the sounding. This single BS value is determined from the recorded time-series (pings) by using one or several time samples and transforming their magnitudes into a reflectivity level, according to the sonar equation. At the end, several BS values from consecutive pings or beams are generally averaged to minimise the variability of successive measurements. How they are calculated, and how (and why) they are averaged, is however open to interpretation.
Different methods are presented to reduce the time-series information to a single BS value in the context of Rayleigh scattering. To anchor these theoretical considerations to actual applications, the processes are applied to field data from a single beam echosounder designed at Sorbonne University and used on well-constrained seafloor patches in the Bay of Brest (France) in 2016. The echosounder was tilted mechanically from nadir to 60° and it transmitted a 100 kHz sine wave of 600 µs duration on the different terrains. The issue of the insonified area compensation of several time-samples is discussed, and inferred backscattering strengths are compared relatively and with ground-truth.
Original languageEnglish
Pages41
Publication statusPublished - 19 Jun 2022
EventInternational Conference on Underwater Acoustics ICUA-2022 - Southampton, UK United Kingdom
Duration: 19 Jun 202223 Jun 2022
https://icua2022.org/

Conference

ConferenceInternational Conference on Underwater Acoustics ICUA-2022
Abbreviated titleICUA-2022
Country/TerritoryUK United Kingdom
CitySouthampton
Period19/06/2223/06/22
Internet address

Keywords

  • underwater acoustics
  • sonar
  • echosounder
  • multi-frequency
  • seabed mapping

ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Ocean Engineering

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