The virtual bat: Echolocation in virtual reality

Abstract

Work in progress is being presented on the effectiveness of using sonar to orientate and navigate in a virtual reality system. The sonar system is based on those of bats, using ultrasonic frequency modulated signals reflected from simple targets. The model uses the reflectivity characteristics of ultrasound, but the frequency and temporal structure used are scaled down by a factor of ten to bring the frequency range and temporal resolution within the capabilities of the human auditory system. Orientation with respect to the ensonified target is achieved by time of flight time delays to give target range, and binaural location information derived from interaural timing differences, interaural intensity differences, and head-related transfer functions. Data on the ability to locate targets as a function of signal frequency, bandwidth, duration and sweep pattern is presented.