| 摘要 |
PURPOSE:To arrange so that the depth of an underground object can be measured with high precision, with the clarification of a channel for a return current, by providing an electric channel for a return current on the ground in parallel with an underground object such as gas pipe, etc. CONSTITUTION:An electric channel 13 for a return current is laid on the ground 5 in parallel with an underground object 1 and a location where a detection coil 9 inside a detection rod 8 is at a right angle with a composite magnetic field of a magnetic field by an underground located object 1 and a magnetic field by an electric channel 13 for a return current, is sought. That is, a signal of induction electromotive force from the detection coil 9 is detected by means of a receiver 21 and then is supplied to an arithmetic processing device 22. In the meantime, to this arithmetic processing device 22, a signal of set inclination angle from a detection rod 8 and a signal of the movement distance of a truck 17 from a ragne finder 20 are supplied. Following this process, the buried depth of an underground object 1 is operated under an arithmetic formula based on a signal of movement distance when a signal of induction electromotive force is zero and a signal of set inclination angle. |
