Yasunobu SAKAI, Tetsuya UNO, Junichi TAKAGI and Tsukasa YAMASHITA

Central R & D Laboratory, OMRON Corporation, Kyoto, 617 Japan

(Accepted October 27, 1994)

The prototype for a ground speed sensor has been designed, fabricated and evaluated. It works on the principle of optical spatial filtering and uses pulse driven light emitting diodes as a source of illumination. The sensor was tested at speeds ranging from 2 to 50 km/h, and an accuracy of 1.5 km/h was obtained with response time of 30 ms, height from ground of from 230 to 370 mm and on various road surfaces. The sensor is viewed as beneficial for use in a vehicle's antilock braking system and will contribute to traffic safety.

Key words : optical spatial filter, ground speed, antilock braking system, light emitting diode, prism array, road surface