@inproceedings{fdi:010067520,
  title = {{F}irst trial of multi-wavelength vector sensor : sediment geoacoustic properties obtained from vessel noise off {S}enegal},
  author = {{R}en, {Q}. and {H}ermand, {J}.{P}. and {V}erbanck, {M}. and {B}rehmer, {P}atrice},
  editor = {},
  language = {{ENG}},
  abstract = {{F}isheries survey {ECOAO} 13, including the collection of surface sediment samples and acoustic propagation measurements, was carried out off the {S}enegalese coast in {F}ebruary 2013. {T}he bottom acoustic properties were determined by geoacoustic inversion using the noise of {R}/{V} {A}ntea as a noise sound source of opportunity. {T}he vessel moved on a straight course with constant engine speed (1627 {RPM}) while the generated noise field was recorded by a vector sensor array deployed from a reinforced hull inflatable boat launched from the vessel. {T}he multi-wavelength array, designed and built at {EHL}, is composed of four pressure sensors with different spacing combinations and two pressure gauges. {T}he inversion approach estimates the bottom geoacoustic properties from observation of range-dependent features of vertical impedance at multiple frequencies and optimization based on a genetic algorithm. {A}s compared to our previous two-element array, deployed offshore {A}mazon, the newly designed array provides more comprehensive observables and therefore more reliable geoacoustic inversion results. {F}or this first trial, the vertical impedance data at the spectral lines of 140 {H}z, 280 {H}z and 321 {H}z were extracted from pairs of adjacent array elements and jointly processed. {T}he bottom compression speed (1640 m/s) and density (1.96 g/cm3) deduced from the posterior probability density functions suggest a sandy seabed. {T}he acoustic inversion results are in general agreement with the grain size analysis of two sediment grab samples, which indicate that more than 80% of the material is composed of well-distributed sand particles of different sizes, the remaining part being shell fragments and silt/clay mixtures.},
  keywords = {{SENEGAL} ; {ATLANTIQUE}},
  numero = {},
  pages = {4},
  booktitle = {{IEEE}/{OES} {A}coustics in {U}nderwater {G}eosciences {S}ymposium ({RIO} {A}coustics)},
  year = {2015},
  DOI = {10.1109/{RIOA}coustics.2015.7473637},
  URL = {https://www.documentation.ird.fr/hor/fdi:010067520},
}