| 摘要 |
PROBLEM TO BE SOLVED: To specify the position of an intruder or an obstacle on a plane bounded by leakage cables by specifying not only the distance in the laying direction of the leakage cables but also the distance in the perpendicular direction to the leakage cables, by utilizing a delay time of radio propagation on a route blocked by the intruder or the obstacle bounded by the pair of leakage cables. SOLUTION: The distance of the intruder or the obstacle in the perpendicular direction from the leakage cables is specified by utilizing the difference of a delay time measured in each frequency with background information wherein the radiation angle of a radio wave emitted from the leakage cable is changed by a frequency change. Otherwise, the distance of the intruder or the obstacle in the perpendicular direction from the leakage cables is specified by utilizing the difference of the delay time by replacing the leakage cables on the transmission side and on the reception side. Not only the distance to the intruder or the obstacle in the laying direction of the leakage cables but also the distance in the perpendicular direction are specified, to thereby enable to specify the planar position bounded by the leakage cables. COPYRIGHT: (C)2004,JPO
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