| 摘要 |
PROBLEM TO BE SOLVED: To provide a speed measuring device capable of simultaneously measuring a speed in a longitudinal axis direction and a speed in a lateral axis direction in a speed measuring device using the Doppler effect of an electromagnetic wave.SOLUTION: The speed measuring device which is mounted on a transportation machine, radiates an electromagnetic wave toward a direction of a fixed object, receives the electromagnetic wave reflected from the fixed object, and measures a frequency difference between a radiation wave and a reflection wave, thereby measuring a speed with the fixed object as a reference. At least two speed measuring devices are provided, and these two speed measuring devices are arranged to respectively rotate in two different directions toward a lateral axis direction on a vertical axis from a longitudinal axis direction of the transportation machine so as to be irradiated with the electromagnetic wave, and obtain the speeds in two directions of the longitudinal axis direction and the lateral axis direction of the transportation machine from a sum of and a difference between the speeds measured by the two speed measuring devices. |
