Using the wingbeat corner reflector effect to increase detection range of avian radar systems

Most avian radars use the resonance effect within the S‐band to estimate the maximum bird detection distance. However, the specified range (2 km) for a standard avian target (SAT) with a 0.5 kg mass and 0.025 m 2 radar cross section (RCS) as reported by the US Federal Aviation Administration is too small to cover the airfield clear zone at airports. The research shows that the measured RCS value of a pigeon is 0.25 m 2 , and furthermore, the authors argue that Ku‐band avian radar can detect a pigeon as a SAT at a longer range, 12 km. They attribute this magnification effect on bird RCS due to the corner reflector effect related to wingbeats. During certain flapping motions, the wings and body of birds in flight act as corner reflectors; thereby, when radar echoes fall upon either face will impinge onto the other face, and subsequently reflected towards the illuminator, thus contributing considerably to bird RCS. The measured RCS of a pigeon is consistent with the theoretical RCS of a dihedral corner reflector. An expanded coverage of the avian radar larger than the main area of an airfield clear zone can improve the detection probability and reduce bird strike hazards.