Maritime apparatus for locating a buried submarine cable
First Claim
1. A submarine cable locating apparatus for detecting a submarine cable by detecting a direct current flowing through the submarine cable and a dc magnetic field created by armoring steel wires of the submarine cable, said submarine cable locating apparatus comprising:
- a submersible robot located below a ship, said robot being provided with a plurality of differential triaxial orthogonal dc magnetic sensing units each comprising two triaxial orthogonal dc magnetic sensors spaced a predetermined distance apart from one another with their corresponding axes set in parallel and each comprising three dc magnetic sensing elements each of which is sensitive only to a dc magnetic field in a specific one of three different axial directions, the three axes of respective dc magnetic sensing elements crossing each other at right angles;
means on said robot for calculating analog difference signals, for each of the x axis, y axis and z axis in a coordinate system, between the outputs of different pairs of two dc magnetic sensors respectively incorporated in said triaxial orthogonal dc magnetic sensing units and having corresponding axes set in parallel;
means for converting said analog difference signals to digital difference signals;
means for transmitting said digital difference signals to the ship;
a processing unit located on the ship and utilizing said digital difference signals to compute the distance between the robot and a submarine cable, to compute the difference in elevation between said robot and the submarine cable, and to compute the direction of the submarine cable; and
means on the ship for displaying the results of the computations performed by said processing unit.
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Accused Products
Abstract
A remotely operated submersible robot 10 is provided with two differential triaxial orthogonal dc magnetic sensing units, 1 and 2, each comprising two triaxial orthogonal dc magnetic sensors spaced at a predetermined distance apart and with their corresponding axes set in parallel; each triaxial orthogonal dc magnetic sensor incorporating three dc magnetic sensing elements sensitive only to a magnetic field in a specific axial direction and disposed such that the axial directions of respective dc magnetic sensing elements cross each other at right angles. Analog signals sent out from the differential triaxial orthogonal dc magnetic sensing units 1 and 2 are converted into digital signals by an analog-to-digital converter, and transmitted to a mother ship 20 via a tether cable 6. The output signals thus transmitted from the aforesaid sensing units are processed by a processing unit installed in the mother ship 20 to compute the distance to a submarine cable, a difference in elevation between the submarine cable and the submersible robot, and the direction of the submarine cable laid down, which are shown on a display.
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Citations
5 Claims
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1. A submarine cable locating apparatus for detecting a submarine cable by detecting a direct current flowing through the submarine cable and a dc magnetic field created by armoring steel wires of the submarine cable, said submarine cable locating apparatus comprising:
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a submersible robot located below a ship, said robot being provided with a plurality of differential triaxial orthogonal dc magnetic sensing units each comprising two triaxial orthogonal dc magnetic sensors spaced a predetermined distance apart from one another with their corresponding axes set in parallel and each comprising three dc magnetic sensing elements each of which is sensitive only to a dc magnetic field in a specific one of three different axial directions, the three axes of respective dc magnetic sensing elements crossing each other at right angles; means on said robot for calculating analog difference signals, for each of the x axis, y axis and z axis in a coordinate system, between the outputs of different pairs of two dc magnetic sensors respectively incorporated in said triaxial orthogonal dc magnetic sensing units and having corresponding axes set in parallel; means for converting said analog difference signals to digital difference signals; means for transmitting said digital difference signals to the ship; a processing unit located on the ship and utilizing said digital difference signals to compute the distance between the robot and a submarine cable, to compute the difference in elevation between said robot and the submarine cable, and to compute the direction of the submarine cable; and means on the ship for displaying the results of the computations performed by said processing unit. - View Dependent Claims (2, 3, 4, 5)
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Specification