Measurement and Analysis of Radar Signals Modulated by Flapping Wings of Birds

Abstract

There are arguments about the scattering mechanism of the 10-dB periodic signal fluctuations posed by the repetitive flapping motion in radar ornithology. We design a dynamic measurement system composed of a network analyzer and a high-speed camera to track dynamic radar signals modulated by the flapping gaits of birds within the S-band, X-band, and Ku-band. The results indicate that the respiration motion contributes little to the bird’s signals, but the flapping wings not only contribute at least 10 dB to the signal fluctuation, but also modulate the radar signals of flying birds related to the flapping gaits, regarding different radar bands, observing angles and bird species. Furthermore, the contributions observed in the tests indicate that our theory of the time-varying wingbeat corner reflector (WCR) effect is correct in explaining the modulation mechanism of the 10-dB signal fluctuations in radar ornithology.

Keywords

• Bird radar signals
• dynamic measurement
• flapping wings
• signal fluctuation
• time-varying wingbeat corner reflector (WCR) effect