HR: 1330h
AN: OS32A-0239    [PDF]
TI: The IMI-30 Seafloor Imaging System: Development of A New NSF Deep-Towed 30kHz Bathymetric Sidescan Sonar System
AU: Rognstad, M
EM: markr@soest.hawaii.edu
AF: SOEST - University of Hawaii, 1680 East-West Road, Honolulu, HI 96822
AU: * Appelgate, B
EM: tba@hawaii.edu
AF: SOEST - University of Hawaii, 1680 East-West Road, Honolulu, HI 96822
AU: Ericksen, T
EM: ericksen@soest.hawaii.edu
AF: SOEST - University of Hawaii, 1680 East-West Road, Honolulu, HI 96822
AB: The Hawai`i Mapping Research Group (HMRG) has been funded by the U.S. National Science Foundation (OCE-0097822 ) to build and operate a new deep-towed 30kHz phase-difference bathymetric sidescan sonar, the Imaging \& Mapping Instrument - 30kHz (IMI-30) . IMI-30 will simultaneously acquire sidescan sonar imagery, phase difference bathymetry, and multibeam subbottom data, with the ability to host other user-supplied instruments as well. Construction of IMI-30 began in early 2003, and the first funded research survey using the system is anticipated to be scheduled in 2004. Here we discuss the planned capabilities of the system, describe the current state of development, and present results from recent test cruises. The IMI-30 design is functionally similar to the HAWAII MR1 and DSL-120 towed sonars, sharing fundamental electronic characteristics, data acquisition computers, and sonar processing software. These shared characteristics allow hardware, software, and support staff to be shared between these systems, resulting in lower operational costs and a larger pool of engineers, technicians and scientists familiar with the maintenance, operation, and data processing requirements of this family of sonars. IMI-30 is fully portable for use on UNOLS global- or ocean-class vessels. Once operational, IMI-30 will be available to all NSF-funded researchers as an NSF facility maintained as part of the University of Hawai`i shared-use equipment pool. Transducers for IMI-30 were fabricated in-house using surplus United States Navy DT605 hydrophones recovered from decommissioned Sturgeon-class submarines. These transducers were designed for use at 30 kHz, and are of an advanced design with multiple element ceramic stacks and exotic materials for head and tail masses. To create long arrays we encapsulated parts of the DT605 array in smaller modules, and tested the sample modules at the Acoustic Test Facility at the Naval Undersea Warfare Center in Keyport, WA. We compared the observed performance with commercial 30 kHz transducers provided by the Unites States Geological Survey. The performance of the modules fabricated at HMRG is excellent (phase response, frequency response, and beam pattern), at a significant cost savings. More recently, system integration tests involving deployments aboard the UH R/V Klaus Wertke have been conducted that demonstrate the capability of the sonar, telemetry, data acquisition and data processing systems, and we present these results here.
UR: http://www.soest.hawaii.edu/hmrg/imi30
DE: 0994 Instruments and techniques
DE: 1294 Instruments and techniques
DE: 3045 Seafloor morphology and bottom photography
DE: 3094 Instruments and techniques
DE: 4294 Instruments and techniques
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting