62 Insight | UUVs performing approximately two months of subsea inspection time under the contract. To that end, the Aquanaut is equipped with 101.1 kWh of battery energy as standard, enabling up to 70 hours of activity between stops. It also comes with a payload capacity of 90 kg, within which it can integrate a variety of 2D and 3D perception sensors, including underwater Lidars, cameras and sonars. Its gripper arms can additionally manipulate subsea objects and impart up to 454 kg of force with full 360° rotation. Seafloor imaging Smaller UUVs (including the new, emerging class of micro-AUVs) are increasingly the tool of choice for research organisations looking to study marine geography, biodiversity and more, while simultaneously spending less (not only in unit costs, but also on surrounding infrastructure, such as boats and cranes, which are required to deploy and recover more standard, large AUVs). To that end, NOAA’s National Centers for Coastal Ocean Science (NCCOS) is set to receive three units of France-based RTsys’ NemoSens AUV in February, the deal having been announced in November 2023. The AUVs have been equipped with SwordFish, an imaging payload developed by Florida-based Arctic Rays. The core of the payload is a 12.3 MP Sony IMX304 camera with global shutter and powered by a back-illuminated colour CMOS detector, which takes still images at 4 fps. It can record 720p HD video at 60 fps, 1080p at 30 fps, or 4K video at 10 fps. Installed about the camera are four fixed, dual-mode LED arrays, which can collectively output 6000 lumens of continuous light in torch mode or 60,000 lumens if set to strobe, thereby illuminating objects viewed by the camera in dark or turbid waters. An Intel i3 core runs processing algorithms for the sensor package, with a 1 TB SSD for onboard data recording; the payload consumes up to 85 W overall in operations, depending on the lighting and image settings. NCCOS is expected to deploy the NemoSens AUVs for the cost-effective collection of hi-res digital images of the seabed to depths of 300 m in the US’s Exclusive Economic Zone, with additional duties in line with NOAA’s ongoing mission of ocean preservation to follow. The NemoSens is designed as a one-person, portable UUV, measuring just under 1 m in length and weighing just under 10 kg in air. Its battery electric powertrain enables up to 6 knots of speed, with typical endurances running in excess of 10 hours. As well as the SwordFish imager, various side-scan sonars, video cameras and environmental sensors number among the compatible mission payloads for prospective data-hungry users. With payloads a vital part of any UUV solution, RTsys announced in October 2023 that it took delivery of 20 Pathfinder DVLs and 10 Wayfinder DVLs from Teledyne Marine, for integration with its NemoSens AUVs, COMET-300 AUVs and µAUVs (micro-autonomous) across scientific, industrial and defence operations. More powerful future From the case studies described above, it is easy to assume that UUVs for military forces and multinational industrial groups will continue to become larger and more mechanically powerful, while UUVs for scientific research teams and other groups with smaller budgets will gravitate towards smaller physical sizes, becoming more software-defined vehicles. The lines, however, may not be so clear-cut. One may take note of the very small UAV systems being used by defence forces today, including the AeroVironment Switchblade and the Prox Dynamics Black Hornet helicopter, which is small enough to be launched by your thumb and forefinger. Conversely, very large science vessels are still being used by ocean research groups to launch AUVs, such as the AutoSub (of ‘Boaty McBoatface’ fame), which have a great many years of design life left in them. Just as large and complex UUVs are set to continue being a hallmark of valuable civilian research and survey work, micro-AUVs packed with copious intelligence, and presenting a small and hard-to-detect footprint will be highly sought after by navies and other forces. As the uptake of UUVs across defence forces continues, they are likely to request underwater systems of varying sizes and specialisations to suit their myriad capability requirements, just as they have done with UAVs and are projected to do with uncrewed ground vehicles over the next few years. February/March 2024 | Uncrewed Systems Technology Three NemoSens AUVs are being delivered to NOAA’s NCCOS for seabed imaging using Arctic Rays’ SwordFish payload (Image courtesy of RTsys)
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