Autosub6000 has just returned from its first sea trials in the abyssal NE Atlantic Ocean near 47 degrees N, 11 degrees W. Working from onboard the UK research ship, RRS Discovery, the objective of the trials was to demonstrate that Autosub6000 is ready for science missions to at least 4500 m deep.
Following a short test deployment in Falmouth Bay (the first time that this AUV had ever run in water), the second mission took Autosub6000 to a depth of 4556m. Autosub6000 controlled and navigated effectively, and the Linkquest Tracklink10000 Ultra Short Base Line (USBL) and telemetry system worked well to a slant range of over 7 km. Later navigation tests proved the accuracy of the AUV dead reckoned navigation system (drifting less than a metre for every one kilometre travelled), and the bottom tracking range of the ADCP (to 240 m altitude).
For the engineers out there, Autosub6000 is a 5.5 m long, 2800 kg, Autonomous Underwater Vehicle (AUV). With a 6000 m depth rating and powered with rechargeable batteries (5 hours recharge time) it has an autonomy of up to 60 hours, or 300km. (There is scope and funding to double this in the future). The free flooded nose section has 0.5 m3 available for any generic scientific payload (such as CTD, cameras, sonars, chemical sensors, samplers, microstructure probes), and up to 250 Watts of electrical power can be made available for the sensors. The navigation system uses an Ixsea PHINS Fiber Optic Gyro (FOG) based Inertial Navigation System, closely coupled to a RD Instruments 300 kHz ADCP. Control modes include constant altitude, constant depth, and up down profiling.