Innovative Solutions to Issues of Persistence
MONCh reported recently on the Boeing win of the development contract for the USN’s unmanned aerial refueler, the MQ-25 STINGRAY (see here for 5 September story). It comes at a time that more and more attention is being paid to solving one of the perennial problems afflicting the UAS operator community – that of how to provide long-term persistence for airborne platforms. Only by extending the endurance of platforms can the real benefits of UAS in the intelligence, surveillance and reconnaissance (ISR) role be realised.
At CyPhy Works in Danvers, MA, the solution is to tether the drone to a ground station that feeds it power. The Persistent Aerial Reconnaissance & Communications (PARC) drone can stay airborne for a week or more, before needing to land for maintenance or repair. Other approaches take an altogether different tack – Silent Falcon Technologies in Albuquerque, NM, is working with the US Defense Advanced Research Projects Agency (DARPA) to demonstrate the feasibility of using a laser to recharge an electric-powered UAS in flight. Another laser-based solution – this time being pursued by the US Army Communications Electronics Research, Development and Engineering Centre in Maryland – is seeking to prove the potential to use UAS-mounted photovoltaic cells to convert laser energy into electricity. The concept has been proven in principle, though currently limited to a range of 500m or so and only applicable to helicopter-type drones that can hover stationary for protracted periods. DARPA, however, is working on taking the concept to the next stage and being able to ‘refuel’ in a similar manner at ranges up to seven miles. Meanwhile the Army is also pushing ahead, with a plan to have a ground-based working prototype in 2019 and an airborne solution by 2020.
If that seems an aggressive schedule – it is not as new a phenomenon as it may seem. As long ago as 2007 DARPA’s Autonomous High-Altitude Refueling programme sought to prove that two RQ-4 GLOBAL HAWK UAS could remain connected for extended periods, which paved the way for the research and engineering development that made STINGRAY possible. Which brings us full circle….
Expect to see this fascinating subject treated in greater detail in a future Technology: The Final Frontier column in Military Technology.