Unmanned Systems Technology 012 | AutoNaut USV | Connectors | Unmanned Ground Vehicles | Cobra Aero A33i | Intel Falcon 8+ UAV | Propellers | CES Show report

28 Dossier | AutoNaut tow passive acoustic arrays to carry out surveys of marine mammal populations and any anthropogenic noise affecting them, enabling verification of sound sources and real-time mitigation. Naturally, the ability to deploy such sensors has significant military potential, which was explored during Unmanned Warrior 2016, a large-scale naval exercise involving the integration of many diverse maritime and airborne unmanned platforms that took place off the coasts of Scotland and Wales in October. Towed array sonar AutoNaut was deployed to Scotland with a set of surveillance sensors that included the W-PAM passive acoustic monitoring system, a towed sonar array from Seiche Marine Acoustic Solutions that was used successfully to hunt for underwater acoustic targets in the anti-submarine warfare segment of Unmanned Warrior. W-PAM is a digital thin line array 25 m long that houses 25 hydrophones that can be individually tuned remotely at any time by the operator. The AutoNaut’s extremely quiet propulsion system make it a very promising platform in which to integrate a passive sonar. “The W-PAM system has already been integrated onto buoy platforms, and we had towed acoustic systems previously, so the integration was relatively straightforward,” Poole says. “The issues we did have were related to noise on the power supply, which was easily isolated, and refining the deployment technique, to minimise the drag effect on AutoNaut and to get the hydrophones a suitable distance away from the surface.” To locate targets accurately, sonars need an up-to-date sound speed profile that plots the speed of sound in water against depth. For the conductivity, temperature and depth measurements that feed into this, along with other oceanographic data that contributed to Unmanned Warrior’s geospatial intelligence theme, AutoNaut integrated a YSI EXO2 multi-parameter sonde supplied by Xylem Analytics. The installation for Unmanned Warrior also included surface sensors such as a variant of the Phobos RESM and threat warner developed for USV use by Teledyne Defence in cooperation with AutoNaut. Covering the frequency range between 2 and 18 GHz, Phobos can detect, analyse and identify multiple radar emitters, measure their bearing relative to the AutoNaut and determine whether they are associated with hostile platforms. AutoNaut is also working with another UK company on a dedicated CESM payload that can carry out the same kind of analysis on radio comms signals. Integrated visual sensors included cameras from Vreo Innovation, with a stills camera mounted 2 m above the deck on a mast, plus a deck-mounted gyro-stabilised camera with a 50x optical zoom lens and power and data transferred into AutoNaut’s mission system through deck connectors. The company has recently developed in-house a 360° stills and video camera system with low-light capability. This can take samples autonomously or when commanded by an operator, with images sent back in near real time. Testing, testing During four years of continuous development and testing – much of it at sea, Poole notes – AutoNaut has taken its USVs from Technology Readiness Level (TRL) 3, denoting early experimental status, to TRL 9, which characterises a system proven in real operations. The sensor fits are mostly at TRL 8, indicating a system that has been qualified in operationally realistic tests and demonstrations. “However, with such rapid global developments in sensor technologies and markets for automation we will always have some products at this stage,” Poole notes. Testing continues at AutoNaut’s Chichester Marina facility on the UK’s south coast, and we visited it in mid-January to watch a team led by operations manager Peter Bromley running a series of comms system tests on the water. It provided an insight into the practicalities of working with the 5 m AutoNaut, which has a maximum displacement of 230 kg, in the confines of a crowded and icy marina. The operation began by breaking the boat out of ice up to 10 mm thick with February/March 2017 | Unmanned Systems Technology Team members manoeuvre the 5 m AutoNaut around moored leisure craft in Chichester Marina in January 2017 in preparation for an afternoon of comms system testing (Photo: Peter Donaldson)