Abstract
In the autonomous mobile robot using ultrasonic range finders, especially in outdoor environment, the ultrasonic range finder is required to detect the object frequently at the short distance for driving control and obstacle avoidance, and to find the landmark object at a long distance for navigation system. However the frequency and the long rang measurement at same time are incompatible in the conventional ultrasonic range finder. The aim of this paper is describe about the ultrasonic range finder that processes these two opposite functions in parallel. This ultrasonic range finder transmits wave coded the pattern that is composed in transmitting patterns of each functions, then calculates cross-correlation between transmitted pattern and received signal at each functions. The experimental results show the ultrasonic range finder measures distance to the short range object frequently and the long range object at same time.
