The model for echolocation of insects by using bat-like sounds

Abstract

Bats use frequency-modulated echolocation to identify and capture flying insects in real three dimensional space. Experimental evidence indicates that bats are capable of locating static objects with a range accuracy of less than 1 μs. A previously introduced model could localize objects in two-dimensional space by accurately estimating the object’s range at each timepoint by extracting temporal changes from the time-frequency pattern and interaural range differences while echoes were measured at two receiving points by intermittently emitting LFM sounds. In addition, this model was shown to localize moving objects in two-dimensional space by accurately estimating the object’s range under the influences of the Doppler shift, which was dependent on the movements. However, it was not evaluated whether this model could detect and localize small sized objects, e.g., small moths, whose echoes were weak. In this presentation, the echoes were measured from two kinds of moth, Spodoptera litura and Helicoverpa armigera. The accuracies of estimated range and direction were examined while echoes were measured from flying moths by intermittently emitting bat-like sounds.