| 摘要 |
PURPOSE:To make it possible to always perform the accurate ultrasonic detection of a distance in spite of the change in a temp. without detecting atmospheric temp., by determining a distance on the basis of the ratio of a reference time corresponding to a reference distance and the ultrasonic wave propagation time between objects. CONSTITUTION:An object 6, wherein a distance is a reference, is subjected to ultrasonic detection by an ultrasonic sensor 3 and an ultrasonic wave propagation reference time is supplied to a microcomputer 11. On the other hand, the ultrasonic wave propagation time between objects due to an ultrasonic sensor 4 is also supplied to the computer 11. The computer 11 can perform the accurate ultrasonic detection of the distance of the object from the ratio of both times and the reference distance in spite of the change in a temp. without detecting atmospheric temp. |
