| 摘要 |
<p>PROBLEM TO BE SOLVED: To make detectable three-dimensional position of a leading end part of a propulsion unit of an underground digging method from above the ground. SOLUTION: A transmitting antenna 16a is set to a leading end part 9 of a propulsion unit 2 thrusting in a soil. When a transmission signal as a continuous carrier wave is fed to the transmitting antenna, the transmitting antenna generates an electromagnetic wave into the soil. A reflected wave of the electromagnetic wave by an underground buried object is received by receiving antennas 16b1-16b5 at least at three set positions on the ground. A time difference of the transmission signal fed to the transmitting antenna and a reception signal at each set position corresponds to a distance between the transmitting antenna and the set position of the receiving antenna. A three-dimensional position in the soil of the transmitting antenna can thus be detected. The transmission signal as the continuous carrier wave fed to the transmitting antenna may be modulated in amplitude, for example, with information expressing a reflect time of the underground buried object or the like, so that the information can be transmitted with use of the electromagnetic wave from the transmitting antenna.</p> |
