Abstract
Ultrasonic range finders have already been used successfully in indoor mobile robots. However, in outdoor environment, the sensor should be robust against noise from vehicle engines, costruction machines and other sound sources. The aim of this paper is to describe a simple, low-cost, and robust ultrasonic range finder witch is based on the cross-correlation technique for accurate ranging of multiple objects in the field of view of the range finder. This sonar transmits wave coded by the pattern that consist of some narrow pulses, then calculates the cross-correlation between the transmitted signal form and the received signal. Furthermore, several this range finder can work simultaneously. The experimental results show this sonar is much more robust against noise than the conventional sonar, and the sensor can find objects fast and precisely for measureing with another sonar simultanousely.
