2019_programme: MULTI-BEAM DOPPLER SONAR FOR MEASURING 2-D VELOCITIES IN A SWATH: SWATHDOP

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  • Session: 16. Advances in acoustic measurement systems: Technologies and applications
    Organiser(s): Tesei Alessandra
  • Lecture: MULTI-BEAM DOPPLER SONAR FOR MEASURING 2-D VELOCITIES IN A SWATH: SWATHDOP
    Paper ID: 843
    Author(s): Razaz Mahdi, Zedel Len , Hay Alex
    Presenter: Zedel Len
    Presentation type: oral
    Abstract: Doppler sonar profiling systems normally employ an array of diverging acoustic beams and measure velocity profiles subject to assumptions about flow homogeneity over the sampled volume. On smaller length scales where homogeneity cannot be assumed, bistatic beam geometries are employed to create (near) coincident component measurements that allow velocity profiles over a limited range. For either approach, measurement of flow spatial structure in more than one dimension requires the use of multiple instruments or requires physically scanning with a single instrument with the assumption of flow stationarity. We are interested in understanding sediment transport over bedforms where flow evolves continuously both in time and space. For this purpose we are developing a pulse-to-pulse coherent swath Doppler system by combining a steerable receiver array with fan beam transmitters in a bistatic configuration. The system operates at 500 kHz with 10% bandwidth sampling transmit pulses at 1.5 ms intervals. The software-defined radio data acquisition and control system limits us at present to 8 independent receiver channels, giving a sample domain that measures 2-D velocities in a ~0.8 m by ~0.8 m region and allows a resolution of about ~3 cm in the plane of the swath. A coherent sonar simulation model was used to test beamforming algorithms and data inversion methods. We report on prototype trials made at the St. Anthony Falls Laboratory main flume facility with observations of 1-mdeep unidirectional flow at speeds of order 1 m/s over evolving bedforms.
      Download the full paper
  • Corresponding author: Dr Zedel Len
    Affiliation: Memorial University of Newfoundland
    Country: Canada
    e-mail:

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