| 摘要 |
<p>PURPOSE:To enable the accurate measurement of a car speed in spite of the vibration of a car, by detecting the frequency differences of measuring waves from first and second receiver-transmitter and the reflected waves thereof and calculating the car speed on the basis of said frequency difference according to a predetermined numerical formula. CONSTITUTION:First and second receiver-transmitters are arranged to a vehicle so as to be respectively directed to the surface of a road at predetermined angles theta1, theta2 and respectively emit measuring waves with frequencies f1, f2 toward the surface of the road and receive the reflected waves from the surface of the road. A frequency difference detection means detect frequency differences F1, F2 of the measuring waves of the first and second receiver-transmitters and the reflected waves thereof. The speed of each measuring wave is set to C in an speed calculation means and a car speed V is calculated from formulae (wherein K1 and K2 are correction coefficient and DELTAtheta is a variable).</p> |
