OTA testing of drone C2 links

Introduction
The C2 (Command & Control) link is the drone’s lifeline. It carries control commands on the uplink and telemetry on the downlink, and is decisive for flight safety, certification and the ability to operate beyond visual line of sight (BVLOS). A link that loses margin at the wrong range, the wrong orientation, or in the presence of an interferer can, in the worst case, mean loss of control of the aircraft. Under EU Regulation 2019/947, BVLOS operations fall into the Specific or Certified category, where demonstrated performance – not just design compliance – is increasingly important.

Today, link stability is verified primarily through field testing: the drone is flown at various distances and the link behavior observed. This method is weather-dependent, requires airspace clearance, is hard to repeat, and gives late and costly feedback when a design needs to change. Root causes are also difficult to isolate when everything varies at once.

With RanLOS test solutions, the measurement moves into a controlled chamber or test environment. Distance, drone orientation and interference can be controlled exactly and repeatably – making it possible to characterize antenna performance, link quality and interference resilience systematically, rather than by trial and error. This white paper describes how.