| 摘要 |
PURPOSE:To detect an oscillator by providing the oscillator to the tip part of a propulsion tube, receiving an acoustic wave signal from the oscillator by a receiver, and calculating the distance between the oscillator and receiver from the time of signal arrival at the receiver. CONSTITUTION:The oscillator 2 and receivers 21A-21F which synchronize with it are arranged across a ground layer and a pulsive acoustic wave signal from the oscillator 2 is transmitted in the ground and received by the receiver 21A, etc., to calculate the arrival time of the acoustic wave signal between the both and also calculate the distance between the two points. Then, the propulsion tube 1 is thrust by proper distance and then three receivers 21A-21B are set at known positions. The arrival time difference of the acoustic wave signal between two known points is measured to calculate the acoustic velocity. The impulse acoustic wave is sent by the oscillator provided atop of the propulsion tube and the distance between the oscillator 2 and each receiver is calculated from the signal arrival time from the oscillator to the receiver. |
