A comparison of acoustic imagery data from a 12-kHz sidescan sonar and a 12-kHz hull-mounted bathymetric and imaging system

Abstract

Seafloor imaging for the purpose of seafloor characterizations and fine-scale feature identilication has traditionally been performed using towed sidescan systems. In the past 5 years, advancements have been made in using existing hull-mounted multibeam bathymetric systems as imaging systems. These hull-mounted systems are optimized for bathymetry, whereas the towed systems have been optimized for imagery.Two separate surveys were performed using both the University of Hawaii, Hawaii Institute of Geophysics (HIG) Acoustic Wide-Angle Imaging Instrument, Mapping Researcher 1 (HAWAII MR1 or MR1) system and the Navy's hull-mounted multibeam Sonar Array Survey System (SASS) over the same area. The MR1 operates at 11 kHz (port) and 12 kHz (starboard), transmitting and receiving on two rows of elements mounted on each side of the tow body. It has a variable pulse length ranging from 0.5-10 msec, and a sample rate of 1 kHz. In contrast, the SASS system has a hull-mounted transmit array with a multiple element receive array, pulse lengths from 3-7 mwc, and a sample rate of 333