SURVEYING METHOD FOR LOG SIZE BURIED OBJECT

摘要

PROBLEM TO BE SOLVED: To provide a method for simultaneously detecting the position of a long size buried object and a specific portion such as joints of the long size buried object. SOLUTION: With the long size buried object surveying method, the position of the long size object 2 buried in a medium and the position of a marker 3 having a specific frequency of oscillation which is arranged in the vicinity of the long size buried object 2 are detected from the medium surface. An alternating current of the same frequency as the oscillation frequency is sent along the longitudinal direction of the long size buried object 2 and a first electromagnetic field response signal sent from the long size buried object 2 is received to detect the position of the long size buried object 2. Also a second electromagnetic field response signal sent from the marker 3 induced by the first electromagnetic field response signal is received to detect the position of the marker 3.