| 摘要 |
A cable buried under a sea bottom is located by causing to flow in the cable an AC current, and measuring the magnetic flux near the cable. The present cable location system comprises (a) a vehicle for mounting a flux detector, (b) means for applying an alternating current in the cable to be detected, to produce magnetic flux around the cable, (c) a three dimensional flux detector having three detector elements, each having cosine sensitivity characteristics, mounted on said vehicle, the maximum sensitivity direction of each element being perpendicular to one another, and the maximum sensitivity direction of one of the detector elements being directed in the vertical direction, (d) means for separating the output signals of each of said detector elements into a DC component which is caused by the earth's magnetic field and an AC component which is caused by said alternating current, (e) means for determining the direction of the cable from the DC and AC output signals of two detector elements which have directivity in the horizontal plane, and (f) means for determining the horizontal distance and the vertical distance between the cable and the cable detecting system from the AC output signals of the detector elements based on the principle that the magnitude of the flux is inversely proportional to the distance to the cable and the direction of the flux is in the tangential direction of a circle having the center on its cable.
|
