Development of the MBARI Mapping AUV
MBARI has developed an autonomous underwater vehicle (AUV) with capabilities to map the seafloor with higher resolution than is possible with hull-mounted or towed sonar systems.
The MBARI Mapping AUV is a torpedo-shaped vehicle equipped with four mapping sonars that operate simultaneously during a mission. The sonars are a swath multibeam sonar, two frequencies of sidescan sonars, and a sub-bottom profiler. The multibeam sonar produces high-resolution bathymetry (analogous to topography on land), the sidescan sonars produce imagery based on the intensity of the sound energy's reflections, and the subbottom profiler penetrates sediments on the seafloor, allowing the detection of layers within the sediments, faults, and depth to the basement rock. All components are rated to 6000 m depth. The vehicle is launched on programmed missions and runs on its own battery power until it returns to the ship, as programmed, for recovery.
In honor of MBARI's long-time Board member Dr. D. Allan Bromley of Yale University, who passed away in 2004, the mapping AUV was christened the D. Allan B.
AUVs provide important advantages for seafloor mapping, especially in the deep ocean. Since high-frequency sound is required to obtain high-fidelity maps of the seafloor, and high frequencies are attenuated by sea water, it is necessary to get close to the seafloor to produce the highest quality maps. Typically this is done by towing sonars close to the bottom. However, in deep water, especially near rough seafloor, this can be dangerous, slow, and produce data contaminated by ship motion. The AUV provides a faster, more nimble platform to produce very high quality data sets.
New high resolution maps of the seafloor are expected to:
- Drive new science (such as sediment transport from shelf to deep sea)
- Enable deep-sea resource management (such as habitat surveys)
- Help in planning & installing seafloor observatories (such as MARS)