title: Echolocation with bat buzz emissions: model and biomimetic sonar for elevation estimation.
abstract: Just prior to capture the Buzz II emissions of some mouth-emitting bats, such as Eptesicus fuscus, are observed to exhibit spectra having multiple peaks. This paper proposes an echolocation strategy that uses such spectra with energy concentrated in specific frequency bands for determining target elevation. A biomimetic sonar was implemented to produce a tri-modal spectrum by driving a speaker with a signal rich in harmonics. The emission magnitudes at these harmonic frequencies measured as a function of elevation in the zero-azimuth plane form distinct beams. A template was formed from the ratio of the first harmonic and fundamental magnitudes to determine elevation. The elevation estimator exhibited a sub-degree accuracy (SD = 0.4° over a 20° interval centered at the elevation at which these two beams intersect in the zero-azimuth plane. Spectral cues from -40° to +10° elevation allow a qualitative non-linear control of sonar orientation to drive the target to the beam-intersection point where quantitative elevation estimates are available.
authors.affiliation: Intelligent Sensors Laboratory, Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520-8284, USA. kuc@yale.edu
authors.forename: Roman
authors.initials: R
authors.lastname: Kuc
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D000818:Animals; D002685:Chiroptera / Q000502:physiology*; D004455:Echolocation / Q000502:physiology*; D004867:Equipment Design; D008954:Models, Biological; D009949:Orientation / Q000502:physiology; D012371:Robotics; D013018:Sound Spectrography