70 Insight | Defence systems loitering capability using features such as a coaxial dual-rotor electric powertrain. The counter-rotating propellers are used to provide flight and hovering capabilities in as stable and quiet a manner as possible, while also optimising the craft’s tactical applications, portability and payload capacity. “The Pholos is payload-agnostic, so it can serve in commercial or military operations,” says an Overwatch representative. “For the latter, the base of the tubular vehicle chassis can be fitted with interchangeable warheads.” The Pholos has a 6.5 kg MTOW, with a 1.5 kg payload capacity. As standard, it also carries two cameras that are not included in the payload capacity. One faces forward for visual monitoring of the terrain and other features ahead, while the other faces downward for targeting or landing. “The warhead is electronically enabled by a unique code, the operator bearing full responsibility for it, so the UAV can’t arm the warhead by itself,” the representative says. “If a target isn’t found then it can be disarmed and the UAV triggered to return to base. This functionality also allows a mission to be cancelled even in the final descent.” The Pholos can fly for up to 40 minutes on a full battery charge, its range limited only by the range of its data link or GNSS availability, although its modular architecture allows for the use of mesh radios that can extend its range significantly. Overwatch has tested the system at ranges of up to 10 km from its GCS operator. Summary As these cases show, there is now a wide range of defence tasks for uncrewed systems. Logistics, medical and threatcountering missions will soon be the domain of autonomous vehicles, and as systems are better optimised for such capabilities, it begs the question of what the next generation of uncrewed defence vehicles might look like. For instance, many UAVs used to be shaped very similarly to crewed aircraft, but are now being designed with more SWaP and aero-optimised shapes, and with nothing resembling a cockpit. Hybrid and electric powertrains are becoming widespread on land, sea and in the air, for the stealth advantages of their low noise and thermal signatures as well as for meeting defence groups’ sustainability targets. Mitigating climate change is also a growing strategic imperative for military bodies involved in climate-driven conflicts in the future. As an awareness of the importance of sustainability grows in the defence sector, other technologies could become of paramount importance. Recyclable batteries and composites, sustainable kerosenes, hydrogen powertrains and thin-film solar are a few examples of technologies that could be in strong demand from military integrators in the future. And given the strategic importance of protecting vehicle comms from jamming, edge computing could take priority over cloud computing, pushing the development of more powerful, reducedSWaP embedded computers. December/January 2024 | Uncrewed Systems Technology Overwatch Group’s Pholos UAV flies on two counter-rotating props to reduce noise and enhance hover stability over potential targets (Courtesy of Overwatch Group)
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