Unmanned Systems Technology 004 | Delair-Tech DT18 | Autopilots | Rotron RT600 | Unmanned surface vehicles | AMRC | Motion control | Batteries

57 Unmanned surface vehicles | Insight multiple craft will be brought together, including autonomous underwater systems and wave-powered gliders as well as the C-Enduro using a multi-beam echo sounder and a PAM system. This will link SeeByte’s Neptune software to the C-Enduro using a common interface and control system.  Another autonomous system aiming to achieve longer endurance is the wind-powered Saildrone 1 (SD1), which uses a solid, freely rotating wing that is controlled by a tail; its predecessor, Greenbird, currently holds the world speed record for wind-powered vehicles, at 126.2 mph. In 2013, SD1 set a new world endurance record for autonomous sailboats, sailing fully autonomously over 154 miles in 67 hours, before sailing itself back to the dock where it started. Saildrone the company is now working on the next generation of wind-powered USVs, with an eye to survey applications and monitoring illegal fishing fleets. Defence Defence applications have also helped the development of the technology. Minesweepers around the world are coming to the end of their life, so many nations are looking for alternatives, and smaller autonomous craft are seen as a good option here. There is interest in a joint UK-French project, as well as interest from Australia, UAE, Norway and Poland for ASV’s unmanned target boat, the C-Target. Also, by developing target boats and making them reliable, the technology for commercial platforms has improved. For example, Textron has taken the experience from its aerial UAV systems and applied it to developing marine systems using the same kind of architecture and structures. Bill Leonard, director of unmanned surface systems at Textron, says, “USVs are about where UAVs were 15 years ago with the FAA – there was a lot of worry about accidents, but now we are going through the same learning curve.” Textron originally built two demonstrators in 2011, the Common USVs (CUSVs), and the learning from them has been applied to a project for the US Navy’s Unmanned Influence Sweep System, a 30-month programme that began in September 2014 to build unmanned minesweepers that could trigger underwater magnetic acoustic mines to clear a path for other vessels. The CUSVs are intended to be launched from ports, oil rig decks and sea-going vessels, and have a payload bay that can reconfigured for use for different missions. Textron is now building these craft and will deliver them to the US Navy in September 2016 for testing. Currently though the control system specification is only for line of sight so that the craft is in constant communication with a control station, and fully autonomous operation is not part of the project, so comms are a key application. “We have demonstrated OTH links using satellite comms on our vehicles,” says Leonard. “Recent exercises in San Diego were controlled from Maryland. But any time you use OTH it’s about the bandwidth and what information is required to come back over. Basic command and control is relatively low bandwidth but if you need radar or video it becomes more consuming of bandwidth on those data links – but it has been proven in different sea conditions.” Textron highlights the same challenges as ASV, with problems when there are multiple moving objects, for example in a port or harbour, which might not adhere to the coastguard’s regulations. There can also be unexpected situations in shipping lanes when other boats don’t follow the established rules. Textron has also changed the power system for the CUSVs, moving to twin 6.7 litre marine diesel Cummings engines as these are already in the US Navy’s inventory, with all the parts and training to support them. “One thing we didn’t want to do was invent a new propulsion system,” says Leonard. Conclusion The technology for USVs is available now, and the range of emerging applications is allowing that technology to be tested in commercial platforms. This testing is in turn informing the regulatory environment and will, over the next couple of years, allow an expansion of the activity and further significant development. Unmanned Systems Technology | Autumn 2015 Experience gained from Textron’s Common USV demonstrators is being fed into a US Navy autonomous minesweeper programme (Courtesy of Textron)