| 摘要 |
PURPOSE:To obtain a correct data realtime, by installing a magnetic field generating cable on the ground so that outgoing and incoming lines are positioned according to a scheme of execution line of an underground excavator to detect a magnetic field of a cable with the magnetic field detection element of the excavator. CONSTITUTION:A magnetic field generating cable 10 is installed on the ground so that an outgoing line 10a and a incoming line 10b will be positioned separated by an equal interval from a scheme of execution line PL of an underground excavator 20 as required. Magnetic field detection elements S1 and S2 are arranged on the side of the underground excavator 20 to detect a magnetic field generating in the cable 10 with the elements. As the magnetic field is different in the level ratio between right half and left half with a vertical plane of the scheme of execution line PL as a boundary, the excavator is allowed to identify and calculate the horizontal pattern of the cable with respect to the vertical plane of the cable effectively and continuously in a real time by discriminating changes in the level ratio of the magnetic field based on an output of the magnetic field detection element. |
