Localization of flying insects by echolocation

Abstract

Using the echolocation, bats can capture insects in real 3D space. Bats can accurately localize these objects from echoes by emitting the frequency modulation sound. The object's range could be estimated from delay times between the emitted sound and echoes from objects. In the case of flying insects, the echoes were influenced by Doppler shift, that is, the wing beats and flight speed. In the case of the linear frequency modulated (LFM) sound, this range accuracy was dependent on not only the frequency width of emitted sound but also the Doppler shift. It has been shown that the previous proposed model could accurately estimate each range of static objects by using the frequency modulation sound. However, it was unknown whether this model could estimate locations and movements of the flying insect. In this study, the echoes were measured from the flying insect by emitting intermittently the LFM sounds. At the same time, the movements of the insects were measured by the camera. The time-frequency pattern were computed by using the convolution of the chirplet filters. It was examined that the the insect's positions were estimated by extracting the onset from the time-frequency pattern.