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48 space, you can get significant magnetic interference,” he says. “I’m therefore developing my own detector for this, to generate a kind of map of the interference, which will let us rearrange the internal electronics or the power system to minimise that interference.” Developing a VTOL-capable system also requires similar attention at the point of transition between horizontal and vertical flight. Grunbaum says, “The rest is easy, as there is software from eight years ago that is accessible to anyone looking to code a multi-rotor plane autopilot to take-off and fly. “The challenge is what’s happening in the middle, between take-off and flight, when you don’t have enough speed for the wings to have the load they need, or if you are losing lift or getting into a stall. That’s where the code has to manage both worlds, reacting and evolving very quickly to changes in incoming flight data.” Also seeking an innovative approach to a key flight constraint of multi-rotor UAVs is Threod Systems, which recently announced a collaboration with fellow Estonian unmanned systems developer Milrem Robotics. The result is a KX-4 LE Titan quadcopter UAV from Threod, deployed from the central platform of a Themis UGV from Milrem. A tether connecting the Titan to the Themis’ diesel-electric generator supplies power, enabling mission durations far longer than the Titan’s maximum battery-powered endurance of 45 minutes. The exact endurance of the tethered Titan will vary depending on its own power usage and that of its host platform. The Themis can operate from 30 to 90 minutes when running solely on batteries, or from eight to 10 hours when using its diesel-electric drive. It means a tethered UAV need not be constrained to a stationary power point on the ground, but instead can move with the UGV’s 14 kph speed. “By connecting a UGV by tether to a UAV, you have an asset that can run for much longer periods of time while gathering reconnaissance information from a much higher vantage point than a UGV can achieve,” explains Lt Col Ugis Romanovs, military adviser at Milrem. “And since our UGV can be configured to navigate using waypoints, it can be sent out by operators to a location of concern with the UAV docked, so that once it arrives at the necessary coordinates, the UAV can be launched at that point and power can be saved.” Villiko Nurmoja, CEO of Threod, adds, “We use Elistair’s tether solution, and a combination of optical sensing and RF beacons to ensure the UAV and UGV stay reasonably close, within the 100 m cable limit. We anticipate that the final end- state of this collaboration will produce a fully autonomous combination of the two unmanned vehicles, with a single GCS and remote video terminal for troops to command the combined system. “We’re participating in the British Army’s Warfighting Experiment with this platform in November [2018]. There will be Level C trials for the full month, and the Army will test the system in three different scenarios,” he says. Commercial survey Although typically focused on defence users, Insitu recently unveiled its ScanEagle3 UAV, which is designed with commercial operations in mind. The resulting aircraft takes various cues from the company’s ScanEagle and Integrator UAVs. “We moved all the expensive electronics to places that are at the lowest risk of damage relative to the rest of the hull,” says Jeff Decker, ScanEagle3 programme manager. For example, the ScanEagle3’s antennas were moved into the aft August/September 2018 | Unmanned Systems Technology Insight | UAVs By connecting to a UGV’s power supply, Threod’s Titan UAV can operate for far longer than a battery-powered system, and with far greater mobility (Courtesy of Threod Systems) We moved all the expensive electronics to places with the lowest possible risk of damage relative to the rest of the hull