Extended dwell Doppler characteristics of birds and micro-UAS at l-band

Unmanned Aerial Systems (UAS), commonly referred to as drones, are rapidly proliferating bringing about new challenges for security and safety. The reason being their small size and ability to fly low in a highly irregular manner makes them particularly difficult to detect with conventional wide-area surveillance sensors such as a scanning radar. Here, we use staring radar that employs a 2-D antenna array and appropriate signal processing to create a multibeam, 3-D, wide-area, continuously staring surveillance sensor capable of achieving high detection sensitivity, whilst providing fine Doppler resolution with update rates of fractions of a second. Whilst staring radar is able to detect miniature UAS against a background of complex clutter, the necessary high detection sensitivity means that many other small moving targets are detected, birds being a principle example. Good Doppler discrimination is central to the ability to distinguish between genuine drones and other confuser targets such as birds that are reported by the radar sensor. Results from field trials are presented illustrating the signal characteristics of rotary wing micro-drones and birds. Analysis of the detailed data features leads to refinements enabling better discrimination between low observable micro-drones and birds.