METHOD AND APPARATUS FOR DETECTING OUTER PERIPHERY OF LAID UNDERGROUND PIPE

摘要

PURPOSE:To make it possible to detect the underground state of the outer periphery of a laid pipe by providing the antenna of a pulse radar in the inside of the laid pipe, moving the antenna part in the laid pipe, and projecting pulses in the direction of the outer part of the laid pipe. CONSTITUTION:At first, a protecting body 30 of an underground detecting apparatus 10 is inserted into a laid pipe 50. Then, a winder 40 is driven, and the protecting body 30 is moved from one end to the other end of the pipe 50. With the movement of the protecting body 30, a pulse radar 20 is operated. For example, pulse radiowaves having the frequency range of, e.g. 500 - 1,000MHz are transmitted in the all directions of the pipe 50. Thus the cylindrical region including the pipe 50 is searched for the coverage of 360 deg.. In this way, underground obstruction and the like within the specified range from the outer surface of the pipe 50 can be detected.