Lesson learnt from decades of passive radar experiments

Thales has been working on passive radar for more than 20 years. Several demonstrators have been developed to test and demonstrate the capabilities of passive radar for air surveillance. Latest Thales demonstrators exploit Frequency Modulation (FM) radio and Digital Video Broadcasting - Terrestrial (DVB-T) opportunity transmitters. Experiments have been conducted in many different countries with a wide variety of aircrafts and flight patterns. Variety is very important since radar performances usually vary with the environment (mountains, flat lands, weather...), the kind of target (liner, ultra-light...) and its position. This aspect is even more important for passive radars which also rely on available opportunity transmitters whose characteristics are unique for each location. Those numerous experiments allow showing the good performances of passive radar in many different conditions. They also prove the robustness of the developed hardware and algorithms, since they have been run in real-time.