# US 12,222,463 B2 · Method for geomagnetically detecting submarine cable > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,463 B2 - Document ID: US12222463B2 - Status: Granted - Kind: B2 - Application number: 17/790,095 - Filed: 2021-06-22 - Published: 2024-06-20 - Granted: 2025-02-11 - Earliest claimed: 2021-04-14 - Assignees: Electronic University of Science & Technology of Hangzhou - Applicants: Electronic University of Science & Technology of Hangzhou - Inventors: Xueting Zhang; Fang Wang; Xiaoqing Tian; Jingbiao Liu; Zefei Zhu - Web page: https://patentgrep.com/patent/US12222463B2 ## CPC - G01V 3/08: operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) - B63G 8/001: {Underwater vessels adapted for special purposes, e.g. unmanned underwater vessels; Equipment specially adapted therefor, e.g. docking stations (self-propelled or direction controlled diving chambers with mechanical link to a base B63C11/42)} - G01V 3/081: {the magnetic field is produced by the objects or geological structures (characterised by the method of magnetic field measurement G01R33/00)} - B63G 2008/004: {autonomously operating} - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - B63G: OFFENSIVE OR DEFENSIVE ARRANGEMENTS ON VESSELS; MINE-LAYING; MINE-SWEEPING; SUBMARINES; AIRCRAFT CARRIERS (means of attack or defence in general, e.g. turrets F41H) ## Abstract Embodiments provide a method for geomagnetically detecting a submarine cable, including: performing a preliminary detection by controlling an underwater robot equipped with a proton magnetometer; determining a preliminary direction and location of the cable based on preliminary detection information; controlling the underwater robot equipped with the proton magnetometer and two fluxgate magnetometers to launch into the water; controlling the underwater robot to travel over the cable and determining specific location information of the cable; controlling a heading of the underwater robot to move along the preliminary direction of the cable; and controlling the underwater robot equipped with the proton magnetometer and the two fluxgate magnetometers to launch into the water; determining whether a fault in the submarine cable occurs and a location of a fault point, based on Z-axis components of the general geomagnetic field and launching depth data of the underwater robot. ## Claims ### Claim 1 A method for geomagnetically detecting a submarine cable, applied to detection control terminals, comprising steps of: step S01, performing a preliminary detection by controlling an underwater robot equipped with a proton magnetometer; and then determining a preliminary direction and a preliminary location of the cable based on preliminary detection information; the preliminary detection information comprising underwater positioning data and a general geomagnetic field; step S02, performing a route detection by controlling the underwater robot equipped with the proton magnetometer and two fluxgate magnetometers to launch into the water, according to preliminary location information; then, controlling the underwater robot to travel over the cable and determining specific location information of the cable, based on the general geomagnetic field measured by the proton magnetometer during the route detection; and, controlling a heading of the underwater robot to move along the preliminary direction of the cable, based on an X-axis component gradient value obtained by the two fluxgate magnetometers; and step S03, performing a patrol detection by controlling the underwater robot equipped with the proton magnetometer and the two fluxgate magnetometers to launch into the water, according to the specific location information; then, determining whether a fault in the submarine cable occurs and a location of a fault point, based on Z-axis components and launching depth data of the underwater robot measured by the two fluxgate magnetometers; where the proton magnetometer is installed in front of the underwater robot, and the two fluxgate magnetometers are installed on both sides of the underwater robot; wherein the step S02 comprises: step S21, determining a launching location of the underwater robot equipped with the proton magnetometer and the two fluxgate magnetometers, according to the preliminary location information; step S22, controlling the underwater robot to launch at the launching location, and controlling the underwater robot to travel to hover right over the cable; step S23, controlling the underwater robot to translate along the preliminary direction of the cable according to the preliminary direction of the cable, and adjusting a translation direction of the underwater robot according to a change of the general geomagnetic field measured by the proton magnetometer; determining the location hover right over the cable at a peak of the general geomagnetic field after adjusting the translation direction several times, and determining the specific location information of the cable; and step S24, controlling the underwater robot to travel, and controlling the heading of the underwater robot to move along the preliminary direction of the cable, based on the X-axis component gradient value obtained by the two fluxgate magnetometers during a travelling process. ### Claim 2 (depends on 1) The method for geomagnetically detecting a submarine cable according to claim 1, wherein the step S01 comprises: step S11, determining a comb-shaped path covering an entire detection range as a preliminary detection path of the underwater robot equipped with the proton magnetometer, based on a detection range of the submarine cable; step S12, performing the preliminary detection according to the preliminary detection path by controlling the underwater robot under a certain launching depth, and recording the preliminary detection information; and step S13, determining the preliminary direction and preliminary location information of the cable based on the preliminary detection information after the preliminary detection of the underwater robot is completed. ### Claim 3 (depends on 2) The method for geomagnetically detecting a submarine cable according to claim 2, wherein determining the preliminary direction and preliminary location of the cable information based on the preliminary detection information comprises: forming a two-dimensional contour map based on the preliminary detection information; correlating dense areas with maximum values or minimum values of geomagnetic locals; and determining the preliminary direction and preliminary location information of the cable. ### Claim 4 (depends on 2) The method for geomagnetically detecting a submarine cable according to claim 2, wherein the detection range of the submarine cable is a rectangular detection range determined based on historical data of the submarine cable. ### Claim 5 (depends on 1) The method for geomagnetically detecting a submarine cable according to claim 1, wherein the step S02 further comprises a step of determining a specific direction of the cable: after the step S23 and before the step S24, controlling the underwater robot to rotate clockwise and counterclockwise 360 degrees for several times in a hover position, and determining an azimuth angle of the cable based on an X-axis maximum value and a Y-axis maximum value obtained after each rotation, and then determining the specific direction of the cable; and in the step S24, the heading of the underwater robot is controlled to move along the specific direction of the cable. ### Claim 6 (depends on 1) The method for geomagnetically detecting a submarine cable according to claim 1, wherein controlling the heading of the underwater robot to move along the preliminary direction of the cable, based on the X-axis component gradient value obtained by the two fluxgate magnetometers during a travelling process comprises: controlling the heading of the underwater robot to turn to a left, when it is determined that the X-axis component gradient value is greater than an X-axis positive gradient threshold, and a change value of the general geomagnetic field is greater than a change threshold of the general geomagnetic field; controlling the heading of the underwater robot to translate to the left, when it is determined that the X-axis component gradient value is greater than the X-axis positive gradient threshold and the change value of the general geomagnetic field is not greater than the change threshold of the general geomagnetic field; controlling the heading of the underwater robot to turn to a right, when it is determined that the X-axis component gradient value is less than the X-axis negative gradient threshold, and the change value of the general geomagnetic field is greater than the change threshold of the general geomagnetic field; controlling the heading of the underwater robot to translate to the right, when it is determined that the X-axis component gradient value is less than the X-axis negative gradient threshold, and the change value of the general geomagnetic field is not greater than the change threshold of the general geomagnetic field; and where the X-axis component gradient value is a difference between X-axis component values measured by the two fluxgate magnetometers. ### Claim 7 (depends on 1) The method for geomagnetically detecting a submarine cable according to claim 1, wherein the step S03 comprises: step S31, determining the launching location of the underwater robot equipped with the proton magnetometer and the two fluxgate magnetometers according to the specific location information; step S32, controlling the underwater robot to launch at the launching location, and controlling the underwater robot to perform the patrol detection along the direction of the cable under a certain launching depth; and step S33, determining whether a fault in the submarine cable occurs and a location of the fault point based on the Z-axis component values measured by the two fluxgate magnetometers and the launching depth data of the underwater robot. ### Claim 8 (depends on 7) The method for geomagnetically detecting a submarine cable according to claim 7, wherein the step S33 specifically comprises: determining that a current location of the underwater robot has the fault, and the current location is the location of the fault point, when it is determined that absolute values of the Z-axis component values of the two fluxgate magnetometers both exceed a Z-axis component threshold, and an absolute value of a change of the launching depth data of the underwater robot in a same period is less than a change threshold of the launching depth data. ### Claim 9 (depends on 1) The method for geomagnetically detecting a submarine cable according to claim 1, wherein the two fluxgate magnetometers are respectively installed on both sides of the front of the underwater robot. ### Claim 10 (depends on 5) The method for geomagnetically detecting a submarine cable according to claim 5, wherein the step S03 comprises: step S31, determining the launching location of the underwater robot equipped with the proton magnetometer and the two fluxgate magnetometers according to the specific location information; step S32, controlling the underwater robot to launch at the launching location, and controlling the underwater robot to perform the patrol detection along the direction of the cable under a certain launching depth; and step S33, determining whether a fault in the submarine cable occurs and the location of the fault point based on the Z-axis component values measured by the two fluxgate magnetometers and the launching depth data of the underwater robot. ### Claim 11 (depends on 10) The method for geomagnetically detecting a submarine cable according to claim 10, wherein the step S33 specifically comprises: determining that a current location of the underwater robot has the fault, and the current location is the location of the fault point, when it is determined that absolute values of the Z-axis component values of the two fluxgate magnetometers both exceed a Z-axis component threshold, and an absolute value of a change of the launching depth data of the underwater robot in a same period is less than a change threshold of the launching depth data.