Biomimetic Sonar System Performing Spectrum-Based Localization

In this paper, we study echolocation by spectral analysis as a biomimetic, i.e., inspired by bats, mechanism to observe a realistic environment. We propose a method to localize, i.e., to estimate the distance and bearing of reflectors, on the basis of a time-frequency representation of the returned echo similar to the one derived by the bat's cochlea. The sonar system consists of a central transmitter, and two receivers pointing plusmn5deg outward. The method proposed reconstructs the environment by comparing the returned echoes with binaural spectral templates corresponding with echoes from different angles. We further show that a distance matrix defined on the set of templates can be used as a measure of their accuracy and reliability for localization purposes. We include experimental results that validate the system and indicate that it can deal with the complex echo signals received when confronted with realistic reflectors, i.e., possibly consisting of a large number of closely spaced scatterers.