| 摘要 |
<p>PURPOSE:To measure the movement of vehicles, such as car speed, at low costs by using ultrasonic waves. CONSTITUTION:A ultrasonic wave transmitter/receiver TR that transmits ultrasonic waves at a specified depression angle and receives reflected waves from a road surface, and an ultrasonic wave receiver R set, away from the ultrasonic wave transmitter/receiver TR, on a straight line linking the ultrasonic wave transmitter/receiving TR with the road surface to which ultrasonic waves are sent, are provided, and the speed at the time of slow running is, based on the signal of received reflected waves by the ultrasonic wave transmitter/receiver TR, calculated, and further, the speed at the time of a high speed running is calculated based on the signal of received reflected waves by the ultrasonic wave receiver R.</p> |
