Uncrewed Systems Technology 048 | Kodiak Driver | 5G focus | Tiburon USV | Skypersonic Skycopter and Skyrover | CES 2023 | Limbach L 2400 DX and L 550 EFG | NXInnovation NX 100 Enviro | Solar power focus | Protegimus Protection

112 As the UAV takes off, its camera feed appears in a dedicated window, and another window shows the progress of its post-take-off routine. The status window then shows whether that routine has been successful. The map also continuously shows the UAV between numbered waypoints. A further window on the left of the dashboard shows all the missions in progress, and the operator can switch between them. As the UAV prepares to land, the status window indicates with green labels that it has set its precision landing (PL) configuration and is descending, and shows the seconds remaining until it is due to trigger the PL process. This is followed by confirmation that the preliminary pre-landing routine has been completed successfully. A blue indicator shows that the UAV is searching for a PL tag on the Nexus box, then a green label indicates that the PL routine has been triggered and the UAV is landing. Potential problems that might warrant operator action are flagged up with orange caution labels, indicating for example that the UAV is unable to detect the PL tag and is increasing its altitude to 10m, then that it is searching for the tag again. When the UAV has detected the largest PL tag and is heading to it for landing, a blue label in the status window informs the operator. As it approaches, the UAV’s camera feed shows its view of the PL tags, which is displayed on the operator’s screen next to the image of the UAV landing provided by a camera on the ground watching the box. A blue status label then reports that the UAV is landing on the tag, then a green one indicates that the post-landing routine has been initiated. As the landing padwith theUAV withdraws into the box, an orange label says theUAV is ‘avoiding detected obstacles’, an indication that its sensors are still working. Agreen label then shows that the post- landing routine has been successful. The operator is then given the option to stop and save a recording of the mission in a pop-up window that also offers other options such as instant replay, live broadcast, screenshot and photo modes, which can be accessed as needed during the mission. ArUcomarkers The PL tags on the Nexus box are key to automated operation, and are in the form of ArUco (Augmented Reality University of Cordoba) markers, which resemble QR codes. These machine vision markers are widely used in the augmented reality field for camera pose estimation. If that camera is aboard a UAV, its position in three dimensions with respect to the marker can be calculated precisely. Eachmarker consists of a square divided into a 7 x 7 grid, with black-and-white squares representing the binary values of 0 and 1 respectively. The squares around the outside are all black, forming a border around the inner 5 x 5 grid that encodes themarker’s identity and creates the shape that allows 3D pose estimation. Displayed on the Nexus box landing pad, five ArUcomarkers enable the UAV to locate the box, confirms that it is the right one to land on and enables a precision landing independently of GNSS. The box has one large ArUco code on top, while the landing pad, which slides out on runners, shows one largemarker and twomedium- sized ones with a single small one between February/March 2023 | Uncrewed Systems Technology ArUco markers are visible to the UAV at progressively shorter distances, enabling it to guide itself to a precision landing on the pad The last stage of the approach to landing starts at about 1 m above the pad, fromwhich height the UAV can read the smallest ArUco maker