Utilizing an Extended Target for High Frequency Multi-beam Sonar Intensity Calibration
|Title||Utilizing an Extended Target for High Frequency Multi-beam Sonar Intensity Calibration|
|Degree and Program||Master of Science in Mechanical Engineering|
|Number of Pages||75|
|University||University of New Hampshire|
There exists an interest in expediting intensity calibration procedures for Multi-Beam Echo-Sounders (MBES) to be used for acoustic backscatter measurements. Current calibration methods are time-consuming and complicated, utilizing a target that is different from the seafloor. A target of irregularly oriented chain links arranged in a 'curtain' was constructed to simulate an extended surface, like the seafloor. Tests with a 200-kHz SIMRAD EK60 Split-Beam Echo-Sounder (SBES) to investigate the targets scattering strength were performed. These tests suggest that the scattering strength depends on the number of scattering elements. A 200 kHz Reson SeaBat T20-P MBES was calibrated with the same target. This MBES was rotated so that all beams were incident on the target. The final output is a beam-dependent calibration coefficient determined from the sonar equation. The T20-P was then used to collect backscatter in the field along a local survey line, where data were compared to the EK60.