Radar systems for “Sense and Avoid” on UAV

Up to now, UAV are widely used, but only in special conditions, both in space and time, which leads to the notion of "segregated airspace". Sense and Avoid systems must be installed on board the UAV to allow their insertion in the general air traffic. Such systems will include cooperative and non-cooperative sensors for reliability. The radar is likely the most useful non-cooperative sensors because it is an "all-weather" sensor and it provides, by essence, accurate ranging and closing speed. The paper discusses solutions in three radar bands: S, X and Ka bands. For each of them, one or two solutions are presented and the pros and cons are discussed. It will be seen that X band is an interesting solution to be pursued.