Uncrewed Systems Technology 049 - April/May 2023

Platformone An optical coating that combines anti-fogging and anti-reflective properties to boost the performance of Lidar systems and image sensors has been unveiled (writes Nick Flaherty). Researchers in Germany, at the Fraunhofer Institute for Applied Optics and Precision Engineering, and the Friedrich Schiller University Jena, say the coating prevents fogging by using porous silicon dioxide nanostructures that reduce reflections. It was designed for Lidar systems but can be tailored for other optical systems. The coating was developed in response to a need identified by Leica Geosystems, which develops airborne Lidar measurement systems for terrain and city mapping. When there are extreme temperature differences between the environment and the measuring system, fogging sometimes occurs on the optical surfaces. The polymer layer prevents fogging on an optical surface by acting as a water reservoir. However, differences in the refractive indices of the polymer material and the surrounding air leads to unwanted reflections and ghost light. To prevent the reflections, the researchers used very small structures, up to 320 nm high, to create an anti-reflective effect together with water permeability. To make the coating, the researchers used an AR-plas2 plasma-ion-assisted coating machine developed at the Fraunhofer Institute for Applied Optics and Precision Engineering. It allows several nanostructures to be created on top of each other, etching a nanostructure into the anti-fog coating and then fabricating a second nanostructure on top. That allows the refractive indices of the nanostructures to be adjusted to achieve very low reflections over the wide spectral range required by a Lidar sensor. Samples manufactured with this new coating technology have already been used successfully for a year in several airborne Lidar prototypes operating in various climatic conditions around the world. Because the structures are generated in a standard plasma system, the new approach can be easily incorporated into commercial manufacturing processes. Sensors Fog-proof coating Dr DonoughWilson Dr Wilson is innovation lead at aviation, defence, and homeland security innovation consultants, VIVID/futureVision. His defence innovations include the cockpit vision system that protects military aircrew from asymmetric high-energy laser attack. He was first to propose the automatic tracking and satellite download of airliner black box and cockpit voice recorder data in the event of an airliner’s unplanned excursion from its assigned flight level or track. For his ‘outstanding and practical contribution to the safer operation of aircraft’ he was awarded The Sir James Martin Award 2018/19, by the Honourable Company of Air Pilots. Paul Weighell Paul has been involved with electronics, computer design and programming since 1966. He has worked in the real-time and failsafe data acquisition and automation industry using mainframes, minis, micros and cloud- based hardware on applications as diverse as defence, Siberian gas pipeline control, UK nuclear power, robotics, the Thames Barrier, Formula One and automated financial trading systems. IanWilliams-Wynn Ian has been involved with uncrewed and autonomous systems for more than 20 years. He started his career in the military, working with early prototype uncrewed systems and exploiting imagery from a range of systems from global suppliers. He has also been involved in ground-breaking research including novel power and propulsion systems, sensor technologies, communications, avionics and physical platforms. His experience covers a broad spectrum of domains from space, air, maritime and ground, and in both defence and civil applications including, more recently, connected autonomous cars. Professor James Scanlan Professor Scanlan is the director of the Strategic Research Centre in Autonomous Systems at the University of Southampton, in the UK. He also co-directs the Rolls-Royce University Technical Centre in design at Southampton. He has an interest in design research, and in particular how complex systems (especially aerospace systems) can be optimised. More recently, he established a group at Southampton that undertakes research into uncrewed aircraft systems. He produced the world’s first ‘printed aircraft’, the SULSA, which was flown by the Royal Navy in the Antarctic in 2016. He also led the team that developed the ULTRA platform, the largest UK commercial UAV, which has flown BVLOS extensively in the UK. He is a qualified full-size aircraft pilot and also has UAV flight qualifications. Uncrewed Systems Technology’s consultants 17 Uncrewed Systems Technology | April/May 2023 The coating was designed for Lidar sensors but is suitable for a variety of optical systems