Ultrasonic sensors present one of the most costeffective
digital distance measurement systems
available for mobile applications. Their effectiveness
is limited, however, in applications involving complex
environments and when information on sensor
position is unavailable. This paper focuses on the
implementation and limitations of ultrasonic sensors
and system design considerations during development
of an Electronic Travel Aid [ETA] for the visually
impaired utilizing ultrasonic sensors and vibrotactile
feedback. Our work with sensors included signal
filtering and triangulation to improve performance
characteristics of ultrasonic-based measurements.
Additionally, we describe the use of computer
modeling to aid in the design of ultrasonic sensor
systems.