Uncrewed Systems Technology 046

95 Vantis BVLOS network | In operation radio system, so it works as well as any practical command,” Clark says. “That allows us to gather recordable and analysable data on the latency, speed, quality and packets of the outgoing and incoming signals.” Ramsey adds, “We’re also constantly logging signal strength between the ground radios and airborne radios; each of those is dual-redundant so we’re able to take two data points from each ‘unit’. In addition to latency, we’re also testing ‘continuity’, which is how consistently the messages get through on the first transmission attempt, without retries. “Lastly, there’s a throughput component: how much of the data of each message gets through. And when flying C2 coverage tests, we’ll monitor all these signal quality stats between multiple radio towers and the UAV at once, which allows the system to determine in real time, and based on signal quality, which of the ground stations is the best choice for secure C2 at any given moment.” The team must also sometimes conduct ‘encounter flights’, in which Thales instructs a crewed aircraft to fly at an altitude different from that of the UAV, and Clark and his colleagues respond as if the two aircraft were at the same altitude. This is to practise for DAA situations in as realistic a manner as possible without endangering the airborne flight crew. “It flies at us from an unknown location, at an unknown speed, which enables us to test the algorithms designed for notifying us of non-cooperative aircraft. Based on the velocity of that aircraft versus ours, we can make our alert rings larger or smaller to meet the average time necessary to return to base, land in place or land at one of the predetermined alternative zones. All of that helps prove out the test case for safe airborne DAA in the network.” For further UTM safety analysis, all the radar surveillance and ADS-B data can be logged in each flight, to enable full replays and evaluations of how the UAV might have handled different safety- relevant air traffic situations. Naturally, some of that data might, in real time, indicate some safety-critical performance loss in one of the items of mission equipment (be it on the UAV or the ground). If that occurs, the HMI displays a warning to the attending flight test engineer so that the UAV can be landed or at least descend to a safe altitude to minimise the risk of collisions with other aircraft. Post-flight processing and maintenance Although a lot of real-time monitoring of the data takes place – including colour- coding values such as signal strength to allow members of Vantis, Thales and uAvionix to judge the network’s connectivity and coverage at a glance – most of the real analysis of the network happens after the UAV is recovered and its data post-processed. “That’s something we work on internally though, because ideally we can always look to present things like running averages of latency and continuity over time, to give everyone clear indicators that the network equipment is working well,” Ramsey notes. As mentioned, the UAV always returns with a safe margin of remaining battery charge, and after it has landed a fresh round of fully charged packs can be installed. “As the UAV flies, we’ll have several other sets of battery packs on charge, so as long as it lands without taking any damage, we can immediately swap the batteries and keep on flying all day,” Clark says. The cycle of launch, recovery and battery swap continues until the end of working hours for the uAvionix team. In the evening there is a debrief, in which Clark might discuss with his team any points for change or improvement Uncrewed Systems Technology | October/November 2022 A variety of missions are performed to evaluate Vantis’ roll-out, be it in terms of radio tower coverage, air traffic safety or other qualities (Courtesy of uAvionix) While we supply parts to the network, Thales is the systems integrator, so the end-users will be getting just a single solution out of this