2019_programme: ESTIMATING RANGE DEPENDENT SEDIMENT THICKNESS AND REFLECTION COEFFICIENTS FROM BATHYMETRIC DATA FOR IMPROVED SONAR PERFORMANCE MODELLING

• Session: 20. Sonar performance modeling and verification. Applications to active and passive sonar
  Organiser(s): Colin Mathieu, Prior Mark, Heaney Kevin, Ellis Dale
• Lecture: ESTIMATING RANGE DEPENDENT SEDIMENT THICKNESS AND REFLECTION COEFFICIENTS FROM BATHYMETRIC DATA FOR IMPROVED SONAR PERFORMANCE MODELLING
  Paper ID: 827
  Author(s): Stender Dan Henrik Sekse, Søvik André Adelsten
  Presenter: Stender Dan Henrik Sekse
  Presentation type: oral
  Abstract: Knowledge about the underwater environment is critical to ASW-operations in littoral waters. The sonar settings and depth selections can significantly affect the possible detection range for better or worse. Ocean depth and sound speed profiles can be found or measured on site, while bottom sediment composition usually relies on sporadic historical data. Sediment thickness is important for low to mid frequency active sonars, which cannot be found in the traditional sediment databases where only the top layer is sampled. The thickness of sediment deposit in an area will, among other things, depend on the shearing angle of the sediment and the slope of the bottom profile. Utilising available environmental information, such as granular size and bathymetry, an estimate of geoacoustic properties along the bottom profile can be made. When using a sonar performance model, a reflection coefficient for the bottom interface is required. The reflection coefficient is frequency-dependent and depends on the substructure of the bottom. The available information is utilised in a simple and fast calculation which gives the environmental parameters along a bottom profile to be used in a sonar performance model. The goal is to improve the accuracy of predicted sonar ranges without making extensive measurements of the sea floor.
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• Corresponding author: Dr Stender Dan Henrik Sekse
  Affiliation: Norwegian Defence Research Establishment
  Country: Norway
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