| 摘要 |
PURPOSE:To correct a range which is measured with an ultrasonic wave according to the measurement environment by measuring the time that the ultrasonic wave as the same measurement medium requires to travel by a known specific distance which can be considered to be under nearly the same condition with a point to be measured. CONSTITUTION:A signal synchronized 4 by a synchronizing device 3a is received by synchronizing devices 3b provided on the sides of markers 1a and 1b, which are activated. Ultrasonic waves f1 and f2 transmitted by the markers 1a and 1b are received by corresponding sensors 2a and 2b to measure elapsed times from the transmission of the ultrasonic wave to the reception respectively, and the respective distances are calculated 5 and displayed 6. Then, they are outputted to a guidance device 7 and used as control parameters for control over the run of a moving body. Further, the moving body mounts the measured distance correcting device 8 where a marker 1c which transmits an ultrasonic wave of different frequency f3 and a sensor 2c are arranged oppositely at a specific range D from each other. this device 8 measures the time that the ultrasonic wave requires to travel by the distance D and detects an error in the propagation speed of an acoustic wave to correct the measured ranges.
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