DC cable sensors for locating underwater telecommunication cables

In this paper, three novel cable-locating methods for underwater vehicles are presented. In those methods, tri-axial flux gate magnetometers are used to detect the static magnetic field induced by direct current flowing in underwater cables. The position and laying direction of the cable are calculated and displayed on an onboard display. The sea trial was carried out successfully in February 1996. In the experiment, the underwater cable, in which direct current of one ampere was flowing, was accurately located from distance of five meters. The results of the experiment and the theory are described.