Unmanned Systems Technology 027 l Hummingbird XRP l Gimbals l UAVs insight l AUVSI report part 2 l O’Neill Power Systems NorEaster l Kratos Defense ATMA l Performance Monitoring l Kongsberg Maritime Sounder

10 Platform one August/September 2019 | Unmanned Systems Technology Researchers at the Technical University of Munich (TUM) in Germany have demonstrated a system that eliminates the need for GNSS satellite navigation, and instead uses optical cameras for navigation and fully automated landing (writes Nick Flaherty). Using an optical system allows UAVs to operate safely from smaller sites that do not have sophisticated equipment. The development is part of the C2Land project. At large airports, the Instrument Landing System (ILS) allows commercial aircraft to land automatically with great precision. Antennas send radio signals to the autopilot to make sure it navigates to the runway safely. Procedures are also currently being developed that will allow automatic landing based on satellite navigation. Here too a ground-based augmentation system is required. However, such systems are not available for general aviation at smaller airports, which is a problem if visibility is poor, as aircraft simply cannot fly. “Automatic landing is essential, especially in the context of the future role of aviation,” said Martin Kugler, research associate at the TUM Chair of Flight System Dynamics. This is especially so for automated aircraft transporting freight and automated flying taxis, he said. In the C2Land system, the autopilot uses GNSS satellite signals to navigate, but these are susceptible to measurement inaccuracies, for example owing to atmospheric disturbances, so pilots currently have to land a UAV craft by remote control. To achieve a fully automated landing, a team from one of the project’s partners, the Technical University of Braunschweig, therefore designed an optical reference system. This consists of a camera operating in the normal visible range and an infrared camera that can also provide data under conditions with poor visibility. The researchers developed customised image processing software that lets the system determine where the aircraft is relative to the runway according to the camera data it receives. The TUM team then used the optical reference system as part of a fully automatic control system in a research aircraft, a modified Diamond DA42. The aircraft has a fly-by-wire system, enabling control by means of an advanced autopilot, also developed by the TUM researchers. To make automatic landings possible, additional functions were integrated into the software, such as comparison of data from the cameras with GPS signals, calculation of a virtual glide path for the landing approach as well as flight control for various phases of the approach. Airborne vehicles GNSS-free navigation TUM’s optical cameras provide automated aircraft landings without using ground-based systems (Courtesy of C2Land) In a similar development to that by TUM, researchers in Russia have also unveiled a UAV that uses optical cameras. The Photon 601 was built by a team at Samara University to be independent of navigation systems such as GPS and GLONASS. Its navigation system recognises ‘support points’ such as landmarks on a map that are set beforehand along the route using gyro-stabilised optical and infrared cameras. These points are identified using machine learning in an image recognition system to provide course corrections. The researchers have tested the 50 kg UAV, which has a range of 400 km and can fly up to an altitude of 5000 m. The video link has a range of 120 km. The Photon 601 uses machine vision to identify landmarks to navigate without the need for a GNSS satellite signal (Courtesy of University of Samara)