Autosub3was designed, developed and built at the NOC in Southamptonwith funding from the Natural Environment Research Council. Seven metres long and weighing 2.4 tonnes (out of the water), the sub is powered by approximately 5000 D-cell batteries. It has a maximum range of 400km, travelling at 6 kilometres an hour for up to 72 hours, with a maximum dive depth of 1600 metres.
The instrument payload is housed in free-flooding areas at each end of the vehicle. In addition to a multibeam sonar system, the AUV carried instruments to measure the salinity, temperature, oxygen concentrations and currents. It was also equipped with an Acoustic Doppler Current Profiler (ADCP) for navigation.
Autosub measurements can include conductivity, temperature, transmissivity, fluorescence, photo-synthetically active radiation (PAR), current velocities, turbulence, ice draft, and water depth. Sub-bottom acoustic profiling can reveal structures of glacial origin in the seafloor sediments, while a water sampler can collect samples for geochemical and biological analyses. Swath bathymetry and sidescan sonar can provide measurements of iceshelf, sea ice and ocean bottom relief at high resolution. Other instruments can also be accommodated on the vehicle.
Dimensions: Length 7 metres, 0.9 metres diameter.
Batteries: Mn alkaline providing more than 500 km range or 6 days endurance in optimal conditions with low power demand.
Depth rating: Carbon fibre pressure vessels rated to 1600 metres.
Propulsion: DC brushless motor driving 5 blade propellor with no reduction gearing and seawater lubricated bearings.
Navigation: Bottom or ceiling tracking using doppler log from 150 kHz ADCP with 500 m range. Inertial navigation system provides navigational accuracy of 0.2 per cent of distance travelled.
Standard sensors: Seatex MRU 6 attitude sensor for magnetic heading, pitch and roll. Digiquartz 430 kT 700 bar pressure sensor for depth data. Simrad Mesotech 808 echo sounder with 300 metre range for altitude information and collision avoidance. Seabird SBE9 CTD and RDI ADCP.
Scientific payload: 1 cubic metre or 100 kilograms in water.
Optional sensors: a variety of commercial and tailor-made packages can be fitted including a fluorometer, transmissometer, oxygen sensor, in situ manganese sensor, flow cytometer, 50 x 0.5 litre water sampler, turbulence probe, additional ADCPs, upward-looking sonars, sidescan sonars, swath bathymetry and digital cameras