Electromagnetic scattering characteristics of flapping bird and experimental validation

摘要

Bird flight has caused many scientists' interest for a long time, of which the flapping is the most common locomotion. Radar provides a powerful tool to observe birds' migration. Aerial birds can be characterised by their electromagnetic scattering characteristics and the radar cross-section (RCS) is one of the most important characteristics. The wings' attitudes of flying birds may induce the RCS values fluctuation; thus the authors can extract the flapping attitudes from the RCS values. In this article, a method of simulating the electromagnetic scattering characteristics of airborne birds was proposed, based on which the flapping attitudes of flapping birds in actual flights were extracted. First, electromagnetic scattering models of a flying bird with different flapping attitudes were built and the FEKO electromagnetic simulation software was used to obtain the bird target's electromagnetic scattering characteristics. Then, the relationship between the flapping angles and the RCS values of the model was studied and the parameters of the flapping angles model were estimated using a parameter estimation method. Finally, based on the measured data, the flapping attitudes of the bird in actual flights were extracted and the accuracy of the scattering model was validated.