Research On Passive Detection Method Of Submarine Cable Based On Magnetic Anomaly

The underwater optical cable transmission network bears and maintains the high-speed transmission of thousands of data,and plays an increasingly important role in the national economy and even in the defense of the military industry.Once the submarine cable fails and cannot be repaired in time,it will cause huge economic and even national defense losses.Therefore,it is necessary to improve the submarine cable detection capability to ensure the normal maintenance and repair work of the submarine cable.By studying the magnetic anomaly perturbation signal generated by the submarine cable in its surroundings under the geomagnetic background,the position information of the submarine cable can be obtained,and thus the theory,simulation and experimental research of the passive detection method of the submarine cable's magnetic anomaly characteristics are carried out.The paper establishes a submarine cable magnetic field model based on the micro-element magnetic dipole model,and determines the influence of different factors on its magnetic anomaly characteristics.The micro-element method is used to divide the submarine cable as a whole to make it meet the magnetic dipole theory;the integral is used to deduce the magnetic field calculation model of the infinite submarine cable,and the comparison and analysis with the COMSOL model verify the reliability of the COMSOL model.The paper carries out modeling and simulation of actual submarine cable,and explores the influence of detection distance,submarine cable length,and background magnetic field on submarine cable magnetic anomalies.The TMR magnetic sensor is selected for characterization and experimental verification to meet the needs of miniaturization of the detection instrument and provide effective actual data guarantee for the verification of the simulation results.The thesis extends to the inversion of the direction of submarine cable laying,and proposes multi-line detection and magnetic imaging inversion detection methods.The verification system required for the inversion was designed and built,and the multi-line positioning test and the indoor imaging test were carried out to verify the two inversion methods proposed in the previous article,and their feasibility was verified.In addition,an outdoor CPA exploration test and a cross-medium test were carried out in the thesis to supplement the previous content and verify the authenticity of the research results.In summary,the study of passive detection methods for submarine cable magnetic anomalies can provide a certain reference for actual submarine cable magnetic anomaly detection,and provide a theoretical basis for its application in actual submarine cable magnetic detection engineering.