Binaural Sonar System for Simultaneous Sensing of Distance and Direction of Extended Barriers

Bat navigation via echolocation has inspired numerous acoustic-based obstacle sensing techniques. In this paper, we use a low-cost, small size, single frequency active binaural system for simultaneous detection of distance and direction of extended obstacles using the time of flight cue. For a binaural system and given size of the transducer, the minimum tolerable separation distance between the emitter and receiver as well as best frequency range for effectively sensing a barrier of any orientation will be assessed by simulation. With the given size of transducers of 6.30 mm in radius and for a working distance of 1 m, the minimum separation distance between the emitter and receiver should not be less than 5 cm and the emitter frequency should not exceed higher than 20 kHz. It will be shown in this article that higher frequency limits the lateral distance detection ability of the system. We experimentally verified the technique for detecting a wall of any orientation with respect to the system’s axis. The approach developed in this paper could be useful for mobile robotics, indoor navigation, and personalized navigation, where a compact configuration is of interest.