Uncrewed Systems Technology 043 l Auve Tech Iseauto taxi l Charging focus l Advanced Navigation Hydrus l UGVs insight l MVVS 116 l Windracers ULTRA l CES 2022 show report l ECUs focus I Distant Imagery

87 Windracers ULTRA UAV | Digest provides extremely robust, failure- tolerant control essential for safe, BVLOS platform operations. A hardware simulation model of flight control systems has been developed to provide a comparative estimate of reliability. The model has been used to create a representation of a traditional architecture as well as the triple-layer DA architecture. Crucially, both models have exactly the same resources (computers/sensors) overall, and stochastic simulation of failures has shown that the architecture gives an order of magnitude increase in reliability compared with the traditional architecture. Command and control The ULTRA has flown extensively in the UK to beyond 100 km from its take-off ground station. Naturally, long- range (BVLOS) operations require high performance and reliable command & control (C2) links. The DA team has applied the same ZPOF philosophy to this aspect of the system, and has developed a comms unit that can seamlessly switch between RF, LTE and satcom depending on signal availability. A system called Cloud Control allows direct C2 links to be established from any connected device using web technologies. This provides a number of benefits. It enables redundancy for ground control hardware, and any tablet/ smartphone/laptop can connect to the platform, making it easy to ensure that an inexpensive ‘hot back-up’ is ready if the primary ground control unit fails. By using authentication and secure user privilege assignment, a range of user types can be defined. Full privileges would provide full control of the platform; more restricted ones can be assigned to allow only limited control. The lowest level of privilege can provide a ‘read- only’ capability, where a user can see the platform location, flight plan and health status. A particular benefit of Cloud Control is the provision of safety pilot information. It has allowed the safety pilot to be equipped with a screen (using a simple and cheap tablet) which displays all the important flight parameters, such as airspeed and height (known as the Safety Pilot Alerting System, SPAS). Depending on the safety pilot’s preferences, these essential flight parameters can be processed using ‘text to voice’ so that he or she can have a continuous audio feed of this information and hence keep their eyes on the platform. The aim of this architecture is to eventually move away from the current model, where ground station operators must be located at the take-off airfields, and instead operate from a centralised location over the internet. Platform control The DA architecture has a strict partition between safety-critical functions and all other functions, to ensure that sufficient and predictable bandwidth is preserved for flight control (navigation, guidance and control). All other functions, such as health monitoring, payload and camera control, are confined to a separate network, with its own dedicated processors. This is known as the Platform Control system. A particular benefit of this approach is that the safety-critical software stack is completely isolated from other functionality, making management of airworthiness and engineering changes for the platform much less complex. Essentially, the core safety-critical flight control code has well-defined, relatively unchanging functionality and requires only infrequent updates and release testing. On the other hand, the secondary aircraft systems’ functionality is more fluid, in response to customer requests for things such as mission sensors and other platform-specific equipment. Automation The design objective for the ULTRA is to fully automate operations and remove the need for piloting skills. The most demanding aspect of a mission is landing, particularly in turbulent crosswinds on rough airstrips. Extensive proving of this functionality has been demonstrated with several hundred successful fully automated landings. Accurate, dedicated redundant height sensors provide fine control of various decision points including flare and engine idle. This auto-loading capability is able to cope with turbulent winds and crosswind landings. Unmanned Systems Technology | April/May 2022 Wind tunnel testing