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

111 GSD [ground sample distance] EO and 5 cm GSD NDVI. That was really helpful, because we wanted to be certain about our flying and seed dropping, and compare our results with what the existing records said the hydrography and depths of the water should be at high and low tides.” He adds that NDVI surveys were performed using a Mapir Survey 2 camera with a red-green-NIR filter, although he anticipates switching to a Micasense Altum-PT in the near future. Glavan says, “Getting the flight and planting planning right is key, because we’re working in some of the harshest conditions in the world, and the geography and conditions of the region we are planting in are really the limiting factors. “The UAVs aren’t a limiting factor. Our sealing, cooling and vibration damping are good enough for 30-minute flights, and we could one day have swarms of UAVs flying and planting across countries. But the success rate of seeds planted is what really matters ultimately, and that is really all about playing by nature’s rules: we have to plant in natural patterns and in locations that make ecological sense.” After a standard checklist of health parameters across the M600’s and octocopter’s batteries, motors, data links and other systems, as well as some quick weather checks, the vehicles were launched one at a time from a patch of astroturf rolled out to minimise the degree of sand around the multi-copters. Planters in flight Each UAV maintains an altitude of roughly 5-9 m above the waterline and an airspeed of 5-10 knots to achieve the desired distribution of seeds into the lagoon, and hence control where they land in the mud. In the trial operations of 2019, only the flight was automated; seed dropping was triggered in real time from the GCS. Now though, the seed handling mechanisms are pre-programmed to release and fire the seeds at time or distance estimates relative to the GNSS waypoints being traversed, in much the same way as logistics UAVs can be triggered to release parachuted cargo at coordinates, or comms relay UAVs can activate their repeaters at measured altitudes. The comms between the payload and autopilot are triggered by a PWM- based data link, for simplicity, ease of use and quick reprogramming where needed. A turnkey comms and control module for future customers is also in the works, to be installed atop an end-user’s preferred UAV and enable plug-and-play interfacing with the payload underneath. Meanwhile, members of Distant Imagery’s team (or members of future teams who adopt Distant Imagery’s equipment and practices for aerial reforestation) will carry out roles such as monitoring the UAV’s vital systems via the aforementioned GCS, observing its motion stability and consistency in air, and preparing the next rounds of seeds or batteries. The work behind each 10-15 minute planting flight is rather labour-intensive, Unmanned Systems Technology | April/May 2022 The UAVs were launched and recovered from astroturf mats to minimise sand and dust ingress