Unmanned Systems Technology 019 | Navya Autonom Cab | Batteries | UGVs Insight | UAV Factory UAV28-EFI | Swiss Aerobotics Hummel | UMEX 2018 report | Antennas | Oceanology International 2018 report

96 batteries, or up to 60 days with 67 MJ lithium batteries. When surfaced, the system can communicate with its operators and transmit collected data via Iridium or RF data link at 900 MHz or 460 MHz, as well as acquire its coordinates on GPS, GLONASS or Galileo if accessible. Advanced Navigation displayed its Subsonus ultra-short baseline acoustic positioning system for UUV navigation and survey work. The system weighs 780 g in the air, and features eight factory-calibrated hydrophones in its array to provide position data accurate down to 0.2 m at 100 m range, and roll and pitch readings accurate to 0.1 º . “Achieving this level of accuracy required multiple developments, including a new correlation technique, beamforming, extensive calibration and a method of continuously measuring the speed of sound through the hydrophones,” Nathan Wilson said. “Minimising multi-path errors near the surface was a primary design goal, and that was achieved using the unique hydrophone array, the advanced coded acoustic signal and dynamic transmission power management.” The Subsonus Tag, Advanced Navigation’s acoustic positioning transponder, was also on show. This integrates pressure-tolerant electronics and batteries into a hermetically sealed housing, and can provide underwater vehicle tracking and remote sensing down to 2000 m with a battery life of up to 18 months. Maxon motor showcased an early version of its upcoming MT20 thruster, which is designed primarily for underwater applications. It features a ducted, three-bladed polyurethane propeller, and is slated to be the smallest system in the company’s production range for underwater applications. “It’s near completion,” said Karl Scheuermann. “We plan to conduct a few more tests to study the thrust and energy consumption, following a minor change to the gearhead we implemented during recent development to improve performance. “The propeller has a diameter of 50 mm, and the system produces a continuous forward thrust of about 1 kgf.” Deep Ocean Engineering showcased its range of robotic marine vehicles, including its two newest Phantom- series USVs, the H-1750 and H-3000. Both systems are catamaran-type designs, with the H-3000 featuring sharp bulbous bows to improve wave-breaking resistance and propulsive efficiency. “The H-3000 is more suitable for oceanic tasks; we typically recommend the H-1750 for lakes, littorals and other calm waters,” said Mike Takeda. The H-1750 is a 1.75 m-long craft built from aluminium alloy, stainless steel and syntactic foams for buoyancy, while the 3 m H-3000 uses mainly aluminium alloy. Both are powered by NiMH batteries, for an endurance of 4 hours at their 7.24 kph standard survey speed. The systems come integrated with HD video cameras that broadcast imagery in real time over 2.4 GHz using omnidirectional antennas. Prevco Subsea Housings has developed a new 3000 m pressure relief valve, the Dual Seal PRV. It is made from an organic thermoplastic, which is resistant to harsh chemicals and provides an alternative to its more expensive metallic systems. “Our pressure relief valves are rated to a depth of 100 m in aluminium and to 6000 m in titanium, and we’ve had a lot of requests for something in between,” Stephen Ashley said. “So we’ve now had one made from PEEK [polyether ether ketone] plastic that has a titanium poppet and is rated to 3000 m. “It is less costly to produce than the all-titanium valve, having a plastic body, and it’s also non-magnetic, dielectric and has no problems with dissimilar metals when fastening it into housings of different materials.” Septentrio showed its AsteRx-U Marine, a dual-antenna GNSS receiver for maritime markets. It also announced upcoming upgrades to the system’s accuracy, with one version that integrates Fugro Marinestar PPP and another supporting SECORX-60 correction services from June 2018 onwards. “Being a dual-antenna receiver, it keeps the system’s heading information stable over the different positioning modes, including RTK and PPP,” said April/May 2018 | Unmanned Systems Technology A version of Maxon’s MT20 thruster Deep Ocean Engineering’s H-1750 USV