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ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) has developed an autonomous underwater vehicle (AUV) for deep ocean seafloor mapping. The MBARI Mapping AUV is a 21" diameter, torpedo-shaped Dorado class vehicle equipped with a 200 kHz multibeam sonar, 110 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp sub bottom profiler. The multibeam sonar incorporates a circular receive array conformal to the vehicle hull, providing 1 degree × 1 degree beam resolution over a 150 degree swath. Navigation and attitude data are provided by an inertial navigation system integrating a laser ring gyro, accelerometers, and a 300 kHz Doppler velocity log (DVL). The vehicle is tracked during missions using an ultra-short baseline navigation system. The vehicle will also include acoustic modem and long-baseline navigation capabilities. A central cylindrical pressure housing contains all of the mapping sonar electronics. The main vehicle control and acoustic communications electronics are housed in a separate pressure housing in the vehicle tail section. Propulsion and steering are provided by a tailcone including an articulating propeller. Li-ion or Li-polymer battery packs allow for a 12 hour mission duration. The assembled package is rated to 6000 m depth. The mapping payload is also designed for ROV mounting, enabling low altitude (< 20 m) high precision missions in topographically challenging sites. The Mapping AUV has now been operated in both autonomous and ROV modes in and around the upper Monterey Canyon, successfully collecting high-resolution multibeam bathymetry and subbottom profile data. Near bottom surveys of the canyon axis achieve bathymetric coverage with a lateral resolution of 1 m and a vertical precision of 0.3 m. The subbottom profiler images subsurface structure to depths of 60 m in soft sediments.
OCEANS, 2005. Proceedings of MTS/IEEE; 02/2005
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ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) is developing an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor is a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. A single cylindrical pressure housing contains all of the mapping sonar electronics, and the main vehicle control and acoustic communications electronics are housed in a separate glass ball. The Mapping AUV is powered by three 2 kWhr Li-polymer batteries, providing an expected mission duration of 12 hours at a typical speed of 1.5 m/s. The assembled package is rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. Initial at-sea testing commenced in May 2004 using the subbottom profiler and 100 kHz sidescan. The sonar package will also be mountable on ROV Ventana, allowing surveys at altitudes < 10 m at topographically challenging sites. The MBARI Seafloor Mapping team is now working towards integration of the multibeam sonar and towards achieving regular operations during 2005.
OCEANS '04. MTTS/IEEE TECHNO-OCEAN '04; 12/2004
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ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) is a
non-profit privately funded research institute devoted to the
development of technology that supports ocean sciences. The MBARI
Vertical Profiler (MVP) is an attempt to combine the high-resolution
data of a profiler with the long-term capability of a mooring. Typical
mooring instrumentation is usually located at discrete depths and
subject to fouling. This can generate time-series data sets that are
incomplete due to a limited number of sensors or erroneous data from
fouled sensors. The number of sensors on a mooring can be increased but
this increases the cost and the risk of a mooring failure. Shipboard
"over-the-side" profilers (e.g. CTD), are capable of collecting a
complete profile of high resolution data but the cost of staying on
station for time-series measurements is prohibitive. The MVP system uses
a variable buoyancy mechanism to transect the mooring line at designated
time intervals. The MVP can also be parked at a depth below the euphotic
zone between profiles and reduce the amount of fouling to the sensors.
During 1999 and 2000, the prototype MVP was designed, manufactured, and
tested at MBARI. The test configuration included the cage and flotation
cones. This assembly was tested in seawater and observed to reach 90% of
its expected terminal velocity. The initial sea trial testing provided
critical data for the development and design of the Buoyancy Engine. The
Buoyancy Engine propels the profiler through the water column by
extending or retracting a piston. This piston movement changes the
volume of the package and therefore the buoyancy of the profiler. The
prototype was also designed for diver installation and recovery from a
mooring. The MVP prototype was first tested from a ship in a series of
over-the-side tests where it performed successfully to its designed
depth (200 m). Next, it was deployed on a test mooring (60 m depth) for
a period of 2 weeks. During these initial tests, a self-contained
profiling CTD along with a miniature fluorometer were used for
evaluation of the profiler performance
OCEANS, 2001. MTS/IEEE Conference and Exhibition; 02/2001
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ABSTRACT: During the Spring and Summer of 2004, MBARI conducted subbottom profile surveys across the main, active channel of the upper Monterey Canyon and two northward trending sub-canyons that appear in swath bathymetry mapping to be mostly filled by recent sediments. Monterey Canyon is the dominant submarine physiographic feature of the Monterey Bay region, and serves as the primary conduit for sediment transport from the coast and shelf to the deep ocean seafloor. These surveys were conducted during the initial sea tests of the new MBARI Mapping Autonomous Underwater Vehicle (AUV). The data were collected using an Edgetech FS-AU 2-16 kHz sweep Chirp subbottom profiler operated on the AUV at vehicle depths up to 250 m. Navigation and attitude data derived from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). Good subbottom data, with typical penetrations of 0.05 seconds, were collected along 140 km of profiles covering an area roughly 3.6 km east-west by 8 km north-south. The profiles clearly show that a single, stratigraphically uninterrupted deposit of sediments has in fact filled the northward sub-canyons. Profiles crossing the main channel also reveal remnants of previous sediment infill along the canyon walls, suggesting that the entire upper Monterey Canyon may have once been filled by sediments as much as 100 m thick.
