Orientation aids for the blind using ultrasonic signpost system

This paper presents an ultrasonic signpost system for the blind, giving precise positional information of landmarks. The proposed system consists of a beacon placed at the location of navigational signs and a hand-held receiver carried by the blind. The beacon emits an ultrasonic wave modulated by a suitable speech message. As the blind traveller comes into transmission range, the message is provided by the receiver. The performance of the proposed system for orientation aids is also discussed.