An extended surface target for high-frequency multibeam echo sounder calibration

An extended calibration target has been developed for calibrating the intensity output of a multibeam echo sounder (MBES). The target was constructed of chain links arranged similar to a curtain, providing an extended surface target with a mean scattering strength of -17.8dB at 200 kHz. The target was used to calibrate a 200kHz MBES, and the MBES was subsequently used to collect seafloor backscatter over sand and gravel seafloors. Field results were compared with calibrated split-beam echo sounder measurements at an incidence angle of 45 degrees. The results suggest that the chain target is a viable MBES calibration tool. (C) 2017 Acoustical Society of America