Water surface vessel dual sensor sea cable route detection system and method

Abstract

The application discloses a kind of water surface ship double sensor's submarine cable route detection system and method, belong to marine detection technical field.System includes double triaxial magnetometer, attitude sensor, positioning module, data processing and control instruction generation module.Detection, first to magnetometer calibration and determine initial waypoint, then synchronously collect head and tail end magnetic field, ship attitude and position data, and adopt UTC time stamp alignment;Original magnetic field data is successively corrected with attitude regularization and Taylor-Lorenz equation preprocessing, eliminate seawater medium attenuation and ship metal interference, solve out heading deviation angle and horizontal offset;Again, based on PID control law is combined with model reference adaptive strategy generation after amplitude limiting heading angular velocity instruction, drive actuator to realize submarine cable route closed loop tracking.The application can significantly improve submarine cable detection precision and tracking stability, shorten detection path, reduce operation cost, suitable for submarine cable fast, high-precision route detection.

Description

Technical Field

[0001] This invention belongs to the field of marine exploration technology, specifically relating to a system and method for detecting submarine cable routes using a dual triaxial magnetometer mounted on a surface vessel. Background Technology

[0002] Submarine cables play a crucial role in marine communications and energy transmission, and their stable operation is essential for ensuring information exchange and energy supply between regions. Submarine cable detection is an important means of ensuring the safe operation of submarine cables and promptly detecting potential faults.

[0003] Currently, there are various submarine cable detection technologies, among which the use of dual magnetic sensors for submarine cable route detection has been applied in some studies. However, most existing submarine cable detection schemes based on dual magnetic sensors rely on underwater detection platforms, such as underwater robots. These underwater platforms have many limitations, such as limited endurance, making it difficult to conduct long-term, large-scale detection operations; high equipment costs, including high purchase and maintenance and operation costs, which also place a significant economic burden on relevant companies; in addition, the operation and control of underwater robots are relatively complex, requiring specialized technicians, which increases the difficulty of detection operations.

[0004] Traditional surface vessel detection methods also have significant shortcomings. When using magnetic sensors, the magnetic signal is easily affected and attenuated by the seawater medium during transmission when the vessel is relatively far from the submarine cable, leading to a decrease in detection accuracy. Furthermore, previous vessel detection path planning was often inefficient, requiring vessels to travel long distances to locate the cable. This not only wastes considerable time and energy but also reduces detection efficiency, failing to meet the demands for rapid and efficient cable detection. Therefore, developing a novel submarine cable detection system and method to overcome the shortcomings of existing technologies is of significant practical importance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a system and method for detecting submarine cable routes using a dual triaxial magnetometer mounted on a surface vessel. By combining a model reference adaptive PID control strategy, high-precision detection and stable tracking of submarine cable routes can be achieved, thereby solving the problems of low detection accuracy, long detection path, low efficiency and high cost in existing submarine cable detection technologies, and realizing more efficient, accurate and low-cost submarine cable detection operations.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A detection method for a submarine cable route detection system with dual sensors for surface vessels includes the following steps: S1, calibrate the dual triaxial magnetometer, calibrate the attitude sensor, and complete signal link testing and algorithm pre-verification; S2, based on historical data or S-shaped path detection, locate the submarine cable position and determine the initial waypoint; S3 uses the magnetic field sensing component to collect high-frequency magnetic field data at the beginning and end as the raw magnetic field signal, the attitude sensing unit to collect attitude data, the positioning system module to obtain position and heading information, and the UTC timestamp synchronization mechanism to achieve time alignment of all data. S4. The original magnetic field signal is regularized using attitude data to obtain regularized magnetic field data. The Taylor-Lorentz equation is used to process the regularized magnetic field data, and the heading deviation angle and horizontal offset of the ship relative to the submarine cable are calculated. S5, Based on the heading deviation angle and horizontal offset, control commands for the ship's heading angular velocity and heading are generated according to the PID control law combined with the model reference adaptive strategy; S6 collects electromagnetic signals and updates parameters in real time, repeating S3-S5 to achieve continuous submarine cable route tracking.

[0007] A further improvement of the present invention is that: Preferably, in S4, the regularization process is as follows: receiving the heading angle, pitch angle, and roll angle from the attitude sensor, and completing the conversion between the geocentric coordinate system and the ship's coordinate system through a rotation matrix to obtain regularized magnetic field data.

[0008] Preferably, in S4, the Taylor-Lorentz equation is:

[0009] Where: A is the effective magnetic field strength after the TL equation is corrected, and it is a three-axis vector data; The data represents the regularized magnetic field; X is the direction cosine matrix of the TL compensation model, calculated from the heading angle, pitch angle, and roll angle; the... This is the compensation coefficient vector for the TL equation.

[0010] Preferably, in S4, the calculation process of the heading deviation angle and the horizontal offset is as follows: extract the electromagnetic induction data from the regularized magnetic field data, process it through the arctangent function to obtain the heading deviation angle of the ship relative to the submarine cable, and obtain the horizontal offset by combining the installation distance of the bow and stern magnetometers, the electromagnetic induction data and the heading deviation angle.

[0011] Preferably, in S5, the heading angular velocity The calculation formula is:

[0012] in: As a proportionality coefficient The integral coefficient is... These are differential coefficients. This is the scaling factor for the horizontal offset. Let t be the heading deviation angle and t be time.

[0013] Preferably, step S5 further includes limiting the generated heading angular velocity control command to a range of [-10° / s, 10° / s].

[0014] Preferably, in S5, a standard second-order model is used to construct the target heading behavior as the ideal desired heading trajectory; the heading tracking error and its rate of change between the ship's actual heading and the ideal desired heading trajectory are calculated; based on the heading tracking error and its rate of change, the PID control parameters are updated online adaptively. The formula for calculating the ideal desired heading trajectory is:

[0015] in, Let be the transfer function of the second-order reference model, and s be the Laplace operator. The system's natural frequency. is the damping ratio.

[0016] Preferably, S5 also includes a preset horizontal offset threshold, generating control commands according to the conventional PID control law when the horizontal offset does not exceed the threshold, and triggering an emergency adjustment strategy when the horizontal offset exceeds the threshold; and performing amplitude limiting processing on the heading angular velocity control commands.

[0017] Preferably, the method also includes a step of calculating the actual path of the submarine cable. Based on the calculated heading deviation angle and horizontal offset, combined with the real-time latitude and longitude of the ship, the relative position deviation between the ship and the submarine cable is converted into the absolute latitude and longitude coordinates of the submarine cable through a geographic coordinate projection conversion formula. The trajectory is then fitted using cubic spline interpolation on multiple sets of real-time latitude and longitude coordinates of the submarine cable calculated during continuous tracking to obtain the actual path of the submarine cable.

[0018] A dual-sensor submarine cable route detection system for surface vessels includes: The magnetic field sensing component includes two sets of triaxial magnetometers, which are used to synchronously collect spatial vector information of the magnetic field around the submarine cable to obtain raw magnetic field data. Attitude sensing unit, including attitude sensors, is used to measure the spatial attitude of the ship in real time; The positioning system module is used to acquire the ship's geographical location information and geographical heading information; The data processing module is used to regularize the original magnetic field signal using attitude data to obtain regularized magnetic field data, process the regularized magnetic field data using the Taylor-Lorentz equation, and calculate the heading deviation angle and horizontal offset of the ship relative to the submarine cable. The control command generation module is used to generate control commands for the ship's heading angular velocity and heading based on the heading deviation angle and horizontal offset, according to the PID control law combined with the model reference adaptive strategy. An actuator is used to receive the heading angular velocity control command and drive the ship to complete the adjustment of heading angular velocity and heading.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a system for submarine cable route detection using dual triaxial magnetometers mounted on a surface vessel. The system employs industrial-grade dual triaxial magnetometers at the bow and stern to collaboratively acquire magnetic field signals. First, TL equation preprocessing is used to offset magnetic distortion caused by seawater magnetic attenuation and magnetic interference from the ship's metal. Then, real-time attitude data regularization correction and engineering error calculation are combined to achieve dual precise correction of the magnetic field signal, far superior to traditional detection methods. A PID (Proportional-Integral-Derivative) control law combined with a model reference adaptive strategy is used to achieve dynamic online updates of control parameters. This allows for adaptation to changes in sea state, speed, and signal quality, avoiding the response lag and heading oscillation problems of traditional fixed-parameter control, thus improving the stability and rapid response capability of submarine cable route tracking. Through real-time path tracking, the vessel can quickly approach the submarine cable, significantly shortening the detection path and reducing detection time compared to traditional ship-based detection methods, thus significantly improving the efficiency of submarine cable detection. Attached Figure Description

[0020] Figure 1 Flowchart of submarine cable route detection method; Figure 2 This is a layout diagram of a submarine cable route detection system based on dual sensors for surface vessels. Figure 3 This is a diagram showing the system connection relationships; Figure 4 This is a schematic diagram for calculating heading deviation and horizontal offset.

[0021] 1. Magnetic field sensing component; 2. Attitude sensing unit; 3. Actuator; 4. Positioning system module; 5. Data processing module; 6. Control command generation module; 7. Data storage module; 8. Communication module; 9. Power supply module. Detailed Implementation

[0022] Hereinafter, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature.

[0023] The method provided in this application can be applied to mobile phones, tablets, wearable devices, in-vehicle devices, augmented reality (AR) / virtual reality (VR) devices, laptops, and ultra-mobile personal computers. In this application, the specific type of terminal device is not limited to terminal devices such as mobile personal computers (UMPCs), netbooks, and personal digital assistants (PDAs).

[0024] It should be noted that the terms "first," "second," etc., used in the specification and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] The first aspect of this invention discloses a detection method for a submarine cable route detection system using dual sensors on a surface vessel, comprising the following steps: S1, Magnetometer Calibration: The magnetometer is calibrated using a Helmholtz coil to generate a standard magnetic field, and a "magnetic field strength-electromotive force" curve is established to correct the error; the attitude sensor is simulated with a typical attitude through a ship attitude turntable, and the model is fitted and corrected using the least squares method to ensure that the heading angle error is ≤ ±0.1° and the pitch / roll angle error is ≤ ±0.05° after calibration. The signal link test and algorithm pre-verification are completed, and the link response time is controlled to be ≤ 50ms.

[0026] The specific process is as follows: A dual magnetometer is placed at the center of a Helmholtz coil. A known magnetic field of 0-100 μT is applied along the X, Y, and Z axes. The induced electromotive force is collected, and a calibration curve of "magnetic field strength - electromotive force" is established to correct linearity errors and zero-point drift. Attitude sensor calibration: Typical attitudes (heading angle 0°-360°, pitch / roll angle -15°-+15°) are simulated using a ship attitude turntable. The collected data is compared with the standard attitude, and the model is fitted and corrected using the least squares method to compensate for installation errors and measurement deviations. After calibration, the heading angle error is ≤ ±0.1°, and the pitch / roll angle error is ≤ ±0.05°.

[0027] System integration testing: The signal link test is used to verify the communication stability and real-time performance of the system data return link and control command link. The data processing module sends test commands to verify whether the data return links of the magnetic field, attitude, and GPS modules are continuous and without packet loss. Small adjustment commands are issued to the actuators to detect the control link response time, with ≤50ms as the passing standard. If this standard is not met, the communication hardware connection is checked, the transmission protocol is optimized, or the communication module is replaced until the test is passed.

[0028] S2, Initial Waypoint Determination: The initial waypoint is determined based on historical data, or by probing the location of the submarine cable through an S-shaped path to obtain the initial waypoint.

[0029] During this process, the initial waypoint can be determined based on historical data. When the calculated value of the horizontal offset reaches the threshold range as described below, the ship's course can be adjusted to execute the mission. If there is no historical data, an S-shaped path can be used to detect the location of the submarine cable to find the initial waypoint.

[0030] S3, Multi-source data synchronous acquisition: After the ship sets sail, the magnetic field sensing component collects magnetic field data at the bow and stern at high frequency, the attitude sensing unit collects attitude data, and the positioning system module obtains position and heading information; the UTC timestamp synchronization mechanism is used to achieve time alignment of all data to ensure the accuracy of data processing.

[0031] After the ship sets sail, the industrial-grade dual triaxial magnetometer of the magnetic field sensing component is immediately activated, synchronously acquiring the spatial vector signal of the magnetic field generated by the submarine cable at the bow and stern of the ship at a high frequency of ≥10Hz. The bow magnetometer outputs X1, Y1, Z1 triaxial induced electromotive force data (measurement range 0-200μT, resolution nT level), and the stern magnetometer outputs X2, Y2, Z2 triaxial induced electromotive force data respectively. This provides engineering-based raw magnetic field signals for submarine cable routing analysis and determination of the relative position of the ship and the submarine cable. Specifically, the raw magnetic field signals include the triaxial induced electromotive force data output by the bow and stern magnetometers.

[0032] S4. Magnetic attenuation of the seawater medium and magnetic interference from the ship's metal during navigation can distort the original magnetic field signal collected by the magnetometer. Furthermore, changes in the ship's course, pitching, and rolling further distort the magnetic field signal, making it impossible to reflect the original magnetic field around the submarine cable. Therefore, the processing flow of this invention is executed in the following order: Regularization Processing: First, the raw magnetic field data from the magnetometer is regularized using ship attitude sensor data. This involves transforming the magnetic field vector from the sensor coordinate system to the geographic coordinate system using an attitude rotation matrix, eliminating errors caused by attitude changes. Taylor-Lorentz Equation (Tolles-Lawson Equation, TL Equation) Preprocessing: The TL equation is then used to correct distortion in the magnetic field data converted to the geographic coordinate system. A high-order fit is performed on the spatial distribution of the magnetic field using a third-order Taylor expansion, and the Lorentz magnetic field distribution law is applied to correct magnetic field distortion caused by magnetic attenuation in the seawater medium and magnetic interference from the ship's metal. Deviation Calculation and Transmission: Finally, based on the preprocessed high-precision magnetic field data, the heading deviation angle and horizontal offset are calculated using a preset geometric method and transmitted to the control command generation module via a high-speed interface. The specific process is as follows: S41, the raw magnetic field data synchronized with the UTC timestamp is transmitted to the data processing module, where it first undergoes signal regularization processing. The data processing module receives the heading angle ψ, pitch angle θ, and roll angle from the attitude sensor. The data is transformed from the Earth-centered Earth-fixed (ECEF) coordinate system to the ship's coordinate system using a rotation matrix. This process corrects the original magnetic field data, offsets the interference of ship attitude changes on the magnetic field signal, and yields regularized magnetic field data. The specific formula is as follows:

[0033] in, It represents the original magnetic field vector in the geocentric-earth-fixed coordinate system, encompassing the uncorrected magnetic field data; It is composed of the ship's heading angle ψ, pitch angle θ, and roll angle. A jointly determined coordinate rotation matrix; This is the normalized magnetic field data transformed into the ship's coordinate system after coordinate transformation. Through this transformation process, the magnetic field data can more accurately reflect the true distribution of the magnetic field around the submarine cable.

[0034] S42, Engineering processing of magnetic field data for TL equations.

[0035] After attitude correction using S41, the regularized magnetic field data in the ship's coordinate system is obtained. This data has already offset the magnetic field projection interference caused by changes in ship attitude, but it still contains magnetic interference generated by the ship's metal structure itself (hard magnetic remanence, soft magnetic induced magnetism) and the inherent attenuation of the magnetic field signal by the seawater medium. Therefore, it needs to be preprocessed using the Tolles-Lawson (TL) equations to achieve secondary purification of the magnetic field signal, providing high-precision raw data for subsequent calculations of the difference between the two magnetometers, heading deviation, and horizontal offset. The specific preprocessing formula adopts the matrix optimization form of the standard TL equations, balancing compensation accuracy and computational efficiency. The formula is as follows:

[0036] Where: A is the effective magnetic field strength after the TL equation correction, which is a three-axis vector data consistent with the magnetometer acquisition dimension; X is the direction cosine matrix (1×9 dimensions) of the TL compensation model, obtained from the ship attitude angle calculation in step S41, including the direction cosines of the geomagnetic field in the three axes of the ship coordinate system and the time derivatives of the direction cosines, specifically... ,in The direction cosines of the Earth's magnetic field along the three axes of the ship's hull are given. The time derivative of the cosine in the corresponding direction (reflecting the rate of attitude change); The compensation coefficient vector of the TL equation (9×1 dimension) includes constant hard magnetic compensation coefficient, induced soft magnetic compensation coefficient and eddy current magnetic compensation coefficient. All of them were determined in advance through static calibration and dynamic sea trial. During the calibration process, magnetic field data and attitude data under different attitudes were collected simultaneously and fitted by the least squares method.

[0037] This step, through the engineering application of the TL equation, precisely counteracts the hard magnetic remanence, soft magnetic induction, and eddy current magnetic interference caused by attitude changes resulting from the ship's metal structure, effectively solving the problem of magnetic field signal distortion. The distortion error of the corrected magnetic field data is reduced by more than 80%, and the output effective magnetic field data A possesses high precision and high stability. It can be directly used as the core input data for subsequent calculations of the magnetic field strength difference between the two magnetometers and the heading deviation, providing reliable data support for the stable tracking of ships along the coastline.

[0038] Meanwhile, the temperature-compensated attitude sensor captures real-time changes in the ship's attitude, and obtains the heading angle (ψ), pitch angle (θ), and roll angle (φ) in real time through built-in high-precision components. The heading angle is used to determine the ship's direction of travel, while the pitch and roll angles provide precise information for correcting magnetic field signal deviations caused by attitude changes. Attitude measurement errors are ≤ ±0.05° for the heading angle and ≤ ±0.02° for the pitch / roll angle. The BeiDou / GPS dual-mode positioning module continuously acquires latitude and longitude (Lat, Lng, positioning accuracy ≤ 2m) and geographic heading information, providing the ship with absolute position reference and navigation direction benchmark, supporting multi-source data fusion processing and precise ship navigation. All sensor data is synchronized at the hardware level using a UTC (Coordinated Universal Time) timestamp synchronization trigger mechanism, with an alignment error ≤ 1ms, ensuring that multi-source data are on the same time reference and guaranteeing the accuracy of subsequent engineering data processing.

[0039] S43, according to appendix Figure 4 The geometric method shown is used to calculate the heading deviation and horizontal offset. After completing the magnetic signal processing, the data processing module obtains the triaxial magnetic field data from the dual magnetic sensors. Based on the geometric relationships in Figure 4: O1 and O2 are the installation positions of the bow and stern dual magnetometers of the ship, and O is the ship's reference point; E1 and E2 are the projection points of the magnetometers onto the cable axis, and the straight lines containing F1 and F2 are the projection lines of the cable onto the sea level. First, the horizontal magnetic field components A1 and B1 of the bow magnetometer are extracted. Based on the distribution characteristics of the cable's magnetic field perpendicular to its direction in the horizontal plane, the angle between the ship's heading and the cable's extension direction, i.e., the heading deviation angle, is calculated using the arctangent function. The calculation formula is:

[0040] This function directly outputs angles within the range of [-180°, 180°], which can accurately reflect the angular relationship between the ship's course and the cable's direction, providing a highly accurate reference for the ship to adjust its course accordingly.

[0041] S44, combining the installation spacing L of the first and last magnetometers and the magnetic field data, then combining the installation spacing L of the first and last magnetometers and the amplitude of the horizontal magnetic field component measured by the two magnetometers. and Vertical components C1, C2 and heading deviation angle Based on the inverse relationship between magnetic field strength and distance, the vertical distance from the ship's reference point O to the cable axis, i.e., the horizontal offset Y, is calculated using the following formula. The sign of Y reflects the relative position (Y>0 for right side, Y<0 for left side, Y=0 for coincidence of the centerline). The calculation uses triaxial magnetic field data collected by the bow and stern dual magnetometers and the installation spacing L of the bow and stern magnetometers. The calculation formula is as follows:

[0042] When current flows through a submarine cable, the magnetic field is axially symmetrically distributed. When a ship is located on either side of the cable, the signs of specific axis components of the magnetometer are symmetrical. Combined with the calculation formula, the sign of Y directly reflects the relative position: Y>0 indicates the right side of the cable, Y<0 indicates the left side, and Y=0 indicates the centerline coincides.

[0043] S5, the control command generation module generates a limited heading angle rate command based on the PID control law and adaptive strategy. After safety verification, it is sent to the actuator. The servo motor converts it into a rudder angle command and drives the rudder surface to move.

[0044] During this process, the control command generation module uses the heading deviation output by the data processing module. And horizontal offset Y.

[0045] In a specific example, the ship's heading angular velocity command is generated according to a preset PID control law. PID control, as a classic and effective control algorithm, can fully utilize the proportional, integral, and derivative characteristics of the deviation to precisely control the course adjustment of a ship. Its specific expression is:

[0046] in: As a proportionality coefficient, it can quickly respond to the current course deviation, enabling the ship to make rapid course adjustment actions; It is the integral coefficient, and its main function is to eliminate long-standing static deviations and ensure that the ship can ultimately and accurately align with the submarine cable route. It is a differential coefficient, which can effectively predict the trend of deviation changes, adjust the control action in advance, enhance the stability of the system, and avoid the ship from experiencing violent oscillations during course adjustment. It is a proportional coefficient for horizontal offset, enabling the ship to focus on correcting deviations in the horizontal direction.

[0047] Furthermore, in order to overcome the problems of response lag, oscillation and poor anti-disturbance capability that traditional fixed-parameter PID control is prone to in the scenario of long-distance detection of submarine cable magnetic signals, this invention introduces the concept of model reference adaptive control (MRAC) to adjust the PID parameters online, realize the dynamic self-optimization of control parameters, and enable the heading control to have the ability to respond quickly, resist disturbances strongly and adapt to environmental changes.

[0048] To ensure that changes in the ship's heading have predictable, controllable, and non-overshooting response characteristics, a standard second-order model is used to construct the target heading behavior:

[0049] in: Let be the transfer function of the second-order reference model, and s be the Laplace operator; The system's natural frequency is pre-designed based on control performance indicators; The damping ratio determines the smoothness of the heading response and is calibrated by the system design; the desired heading command r(t) (i.e., the ship's current heading angle and heading deviation angle) is used. The sum of ... Then the Laplace form of the model output is: By performing an inverse Laplace transform on it, the time-domain signal of the model output can be obtained:

[0050] The model outputs The ideal desired course trajectory is used to compare with the ship's actual course, forming a closed-loop error-driven control parameter update. This is the core basis for the present invention to achieve control that is "directional, targeted, stable, and oscillating".

[0051] The heading tracking error is defined as: , The desired heading angle trajectory output by the model; This represents the ship's actual heading angle, measured in real-time by the ship's attitude sensors. It signifies the degree to which the system's current heading deviates from the desired ideal heading. This error is used not only for control output but also as a direct driving force for the adaptive updating of PID parameters, ensuring that parameter adjustments always converge in the direction of reducing heading deviation. Error change rate. It represents the trend of course change and improves the controller's sensitivity to dynamic transition processes.

[0052] To avoid the shortcomings of traditional PID parameters being fixed and unable to adapt to different sea states, signal quality, speeds, and turning inertia, this invention adopts an error-driven adaptive update mechanism, enabling the PID parameters to be adjusted in real time according to the system's operating status.

[0053] in: , , These are the update rates of the proportional, integral, and derivative coefficients of the PID controller, respectively. , , ε is the pre-calibrated adaptive gain coefficient, determined by system identification and simulation experiments; e is the heading tracking error; This represents the rate of change of heading error.

[0054] The core logic of this adaptive update mechanism is as follows: proportionality coefficient Adaptive adjustment: update rate With current error e and actual heading Proportional. When the heading deviation is large. It will automatically increase, allowing the controller to respond quickly to deviations; when the deviation decreases, This reduces the risk of overshoot and oscillation, while also incorporating actual heading information to make the adjustment more closely match the ship's current motion.

[0055] Integral coefficient Adaptive adjustment: update rate It is proportional to the current error e and its integral term. When the error persists for a long time, the integral term increases. Automatic enhancement eliminates static biases in the system, ensuring the vessel ultimately aligns accurately with the cable route; once the error is eliminated... This reduces the risk of control lag caused by integral saturation.

[0056] Differential coefficients Adaptive adjustment: update rate Compared with the current error e and its rate of change Proportional. When the error changes drastically (such as a rapid change in heading), Automatically increases to suppress the trend of deviation changes in advance, enhances the system's damping, and avoids violent oscillations of the ship during adjustment; when the error tends to stabilize... This reduces unnecessary control interventions and improves system response speed.

[0057] Through this error-driven adaptive update mechanism, the PID controller parameters can be dynamically adjusted according to different sea conditions, speeds and signal quality, always maintaining optimal control performance and effectively improving the robustness and adaptability of the ship's submarine cable tracking system.

[0058] Generate heading angular velocity command Subsequently, to prevent overload damage to actuators (such as servos or propulsion devices) from receiving excessively large commands, it is necessary to limit the range of the commands. The range of values ​​for is strictly limited to [ [10° / s, 10° / s] ensures that the actuator operates within a safe and reliable working range, effectively protecting the hardware of the actuator and extending its service life.

[0059] In a specific example, to ensure the accuracy of submarine cable route tracing and the safety of ship navigation, a preset horizontal offset threshold is used. During operation, the system will continuously compare the currently calculated horizontal offset Y with the preset threshold. A comparison and judgment are performed, and the corresponding control strategy is triggered based on the judgment result. The specific process is as follows: Not exceeding the threshold (|Y|≤) When the vessel is within a precisely detectable range of the submarine cable, control commands are generated using a conventional PID control law to ensure stable and accurate tracking of the cable route. If the threshold (|Y|>) is exceeded... This indicates that the horizontal distance between the vessel and the submarine cable exceeds the range that conventional control strategies can effectively handle, requiring the triggering of an emergency adjustment strategy to prioritize correcting the horizontal offset. The specific operational logic is as follows: Temporarily adjust the control coefficient: Increase the horizontal offset ratio coefficient K y This system enhances the impact of horizontal offset on control commands, enabling vessels to respond more quickly to horizontal deviation correction requests. It also limits the magnitude of course deviation correction: reducing the weight of course deviation correction in control commands to prevent the vessel from excessively pursuing the cable course, which could further amplify the horizontal offset and ensure effective control of horizontal position deviation while adjusting course. Furthermore, it switches operating modes: if the horizontal offset Y exceeds the threshold for three consecutive control cycles, the system automatically switches to "horizontal priority mode." In this mode, the vessel speed is temporarily reduced, and the magnetic field acquisition time is extended to increase the sample size of magnetic field data, thereby improving the accuracy of horizontal offset calculation and providing data support for more precise horizontal offset correction.

[0060] To further ensure ship navigation safety and system stability, a safety verification logic is added to the control command generation stage: Magnetic field data anomaly verification: If abnormal magnetic field data occurs, such as a sudden change in the magnetic field gradient (exceeding the normal fluctuation range), it indicates that the magnetic field environment around the ship may be disturbed (e.g., the presence of other metal objects nearby, sudden changes in the marine environment, etc.). In this case, the system automatically switches to "safe mode" and outputs a default small-amplitude command (e.g., ...). This allows the vessel to maintain its current course and speed, preventing it from deviating from its safe course due to incorrect control commands.

[0061] Actuator fault verification: Real-time monitoring of feedback information from actuators (such as steering gear and propulsion device). If an actuator fault signal is received (such as steering gear jamming, abnormal propulsion device speed, etc.), it will automatically switch to "safe mode" and output safety commands to ensure that the ship is in a controllable state, buy time for subsequent fault diagnosis and maintenance, and avoid the fault from escalating and causing more serious safety accidents.

[0062] Finally, the marine actuator (taking the steering gear as an example) receives the heading angular velocity command issued by the control command generation module. Subsequently, based on the industrial performance parameters of the marine steering gear and the ship's motion engineering model, the commands are converted into precise rudder angle movement commands. The steering gear control system incorporates a dedicated marine control algorithm, capable of accurately interpreting heading and angular velocity commands. When converted to the rudder angle command δ, the conversion relationship satisfies:

[0063] in, The rudder angle-angular velocity conversion coefficient, calibrated for engineering purposes, ranges from 0.5 to 1.0° / (° / s). It is calibrated based on actual ship tests of different rudder models to ensure the accuracy of command conversion. Upon receiving the rudder angle command δ, the rudder drives the rudder surface to rotate to the target angle within 50ms, achieving rapid correction of the ship's course. Furthermore, the system acquires electromagnetic signals and ship attitude data in real time at a frequency of ≥10Hz, dynamically updating the MRAC-PID engineering parameters and repeating the "acquisition-processing-calculation-control-execution" engineering process to achieve high real-time closed-loop control. Simultaneously, the industrial-grade data storage module records and stores all engineering data (raw magnetic field data, attitude data, control commands, and calculation results) in real time with redundant backup, for a storage time of ≥72 hours, for subsequent marine engineering operation analysis, equipment debugging, and data archiving.

[0064] S6: Real-time acquisition of electromagnetic signals to update parameters, repeating steps S1-S5 to achieve continuous submarine cable route tracking.

[0065] The system acquires electromagnetic signals in real time, updates parameters, and initiates the next round of control, achieving closed-loop control. Simultaneously, the data storage module records and stores all data from the detection process for subsequent analysis and evaluation.

[0066] S7, Actual Submarine Cable Path Calculation: Based on the heading deviation angle and horizontal offset Y obtained from S4, combined with the ship's real-time BeiDou / GPS latitude and longitude obtained by the attitude and position sensing unit, the relative lateral position and heading angle between the ship and the submarine cable are converted into the absolute latitude and longitude coordinates of the submarine cable through the geographic coordinate projection transformation formula. The multiple sets of real-time latitude and longitude coordinates of the submarine cable calculated during the continuous tracking of the ship are fitted with the trajectory using the cubic spline interpolation method to obtain a smooth and continuous actual latitude and longitude path of the submarine cable, forming standardized submarine cable route detection results.

[0067] After completing the closed-loop tracking of the ship's submarine cable route, this system executes the actual cable path calculation step, sequentially calculating the pure heading deviation angle, horizontal deviation, and latitude and longitude, as the final engineering output of the entire detection process. This step is entirely based on the previously calculated heading deviation angle and horizontal offset combined with the ship's real-time latitude and longitude, and is automatically executed by the dedicated computing core of the data processing module. The specific implementation process is as follows: Data retrieval for basic calculation: The data processing module retrieves three types of synchronization data (based on UTC timestamp alignment, with a time synchronization error ≤ 1ms) from the local cache, namely: (1) the heading deviation angle calculated by engineering. (2) Horizontal offset Y calculated by engineering; (3) Real-time latitude and longitude of the ship collected by attitude and position sensing unit using Beidou / GPS.

[0068] Real-time latitude and longitude coordinate calculation of submarine cables: Using the ship's latitude and longitude as the absolute position reference, the relative position deviation (heading deviation angle, horizontal offset) between the ship and the submarine cable is converted into the absolute latitude and longitude coordinates of the submarine cable using the geographic coordinate projection transformation engineering formula. The calculation formula is as follows:

[0069] Submarine cable continuous path trajectory fitting: Multiple sets of real-time latitude and longitude coordinates of submarine cables obtained during the continuous tracking of the ship's submarine cable route are used to fit the continuous trajectory using cubic spline interpolation. During the fitting process, the system automatically removes abnormal coordinate points (points where the deviation exceeds the threshold caused by the ship's short-term attitude fluctuations) to ensure the smoothness and continuity of the fitted submarine cable path.

[0070] The actual path of the submarine cable calculated in this step meets the practical engineering needs of submarine cable route detection, marine engineering maintenance, and fault location, realizing the detection target from "relative tracking of submarine cables" to "accurate restoration of the absolute path of submarine cables".

[0071] The second aspect of this invention discloses a detection system for a dual-sensor submarine cable route detection system for surface vessels, see appendix. Figure 1 A layout diagram of the detection system is attached. Figure 2 The system connection diagram illustrates that this submarine cable route detection system uses a surface vessel as its platform. Each functional module is deployed according to the vessel's structure and signal interaction requirements, forming a collaborative system. The system utilizes a surface vessel as its platform to construct a functionally collaborative hardware module cluster and data processing and control system. The hardware module cluster includes a magnetic field sensing component, attitude sensing unit, positioning system module, data processing module, control command generation module, actuator, power supply module, communication module, and data storage module. Each module is scientifically deployed according to the vessel's structure and signal interaction requirements, forming a closed-loop collaborative detection system. The hardware layout and installation are as follows: The surface vessel platform, serving as the carrier for magnetic field detection and control, is responsible for housing all sensors, processors, and actuators. It should possess excellent stability and maneuverability, adapting to navigation environments such as oceans or lakes. The platform provides a propulsion system, a power management system, and structural support. This system utilizes a surface vessel as the detection platform, avoiding the use of expensive underwater detection equipment and reducing equipment purchase and maintenance costs. Simultaneously, the shortened detection path reduces fuel consumption and equipment wear, further lowering the cost of detection operations.

[0072] The magnetic field sensing component 1 is a dual triaxial magnetometer installed at both ends of the ship to synchronously collect spatial vector information of the magnetic field around the submarine cable. The measured magnetic field data can be used to infer the spatial orientation of the submarine cable, estimating the relative position of the ship and the cable (such as heading deviation angle and horizontal offset). The magnetic field sensing component 01 is installed symmetrically at both ends of the ship's bottom, avoiding areas of interference from the ship's metal structure. It is rigidly fixed by a custom titanium alloy bracket, ensuring that the parallelism error with the ship's coordinate system is ≤±0.1°. A 5mm thick shock-absorbing rubber pad is added between the bracket and the hull. The outer shell is IP68 high-level waterproof sealed. The installation distance L between the two magnetometers is 5-15m (adjusted according to the ship length). The data processing module 05 is connected via industrial-grade shielded twisted-pair cable using the SPI (Serial Peripheral Interface) protocol to transmit the magnetic field spatial vector data. The data transmission error rate is ≤10%. -6 .

[0073] Specifically, the magnetic field sensing component includes two sets of triaxial magnetometers. The X, Y, and Z axes of the two sets of triaxial magnetometers are parallel to each other and are fixedly installed at both ends of the ship with a known distance between them. They are used to synchronously collect spatial vector information of the magnetic field around the submarine cable.

[0074] Attitude sensing unit 2 is used to measure the ship's spatial attitude in real time, including yaw, pitch, and roll angles. This is used to regularize the magnetic sensor data and counteract the influence of non-zero attitude angles on the detected data. Attitude sensing unit 2 is deployed in the hull compartment near the ship's center of gravity, rigidly bolted to the hull, and the mounting surface meets flatness standards. It incorporates a built-in temperature compensation circuit to ensure the accuracy of yaw, pitch, and roll angle measurements over a wide temperature range. It communicates with data processing module 5 via an RS485 bus to upload raw attitude data in real time.

[0075] Specifically, the attitude sensing unit 2 includes an attitude sensor; wherein the attitude sensor is used to measure the spatial attitude of the ship in real time.

[0076] Actuator 3 is integrated into the stern steering gear room. It receives control commands and drives the ship to adjust its course, offering rapid response and high control precision to ensure stable tracking of the coastal cable direction. Specifically, the actuator includes a steering gear module and a propulsion device. The composition and connection relationships of each component are as follows: The steering gear module is an electro-hydraulic servo steering gear used to control the ship's course and respond to heading angular velocity commands. The steering gear is rigidly connected to the hull's rudder system via a standard mechanical interface, with minimal transmission backlash, directly converting rudder angle commands into rudder deflection actions. The propulsion device provides forward or backward power to the ship, working in conjunction with the steering gear to achieve course and speed control. Furthermore, the steering gear and propulsion device communicate with the control command generation module 6 via a CAN (Controller Area Network) bus, receiving control commands and providing real-time feedback of operating status parameters, forming a closed-loop control system. Power supply and protection: The actuator is powered by the power module 9 via a dedicated driver. Its control box has an IP protection rating and built-in overcurrent and overvoltage protection circuits, enabling stable operation in high-humidity and high-salt-fog marine environments.

[0077] The GPS (Global Positioning System) or BeiDou antenna of positioning system module 4 is mounted at the highest point of the ship's top (away from the metal structure). It has multi-constellation receiving capabilities, providing high-precision positioning and heading information. This information is used to acquire the ship's geographical location (latitude and longitude) and geographical heading, record the detection trajectory, and serve as the positioning basis for path planning and historical data analysis. It connects to data processing module 5 via a serial port, outputting latitude and longitude, geographical heading, UTC timestamp, etc.

[0078] Data processing module 5 is responsible for receiving data from the magnetometer, attitude sensor, and GPS, and performing processing operations such as filtering, coordinate transformation, and heading and position deviation calculation. An industrial-grade embedded computer is housed in the electromagnetically shielded compartment amidships, mounted on a standard rack via rails. It receives data from the magnetic field sensing component 1 and attitude sensing unit 2 through an expansion interface, transmits the calculation results to the control command generation module 6 via a high-speed interface, and ensures uninterrupted operation via redundant power supply from the power module 9.

[0079] The industrial-grade embedded computer is connected to the magnetic field sensing component and the attitude and position sensing unit via an SPI / RS485 bus. It receives and processes the collected industrial-grade data. First, the original magnetic field data is preprocessed using the TL equation to counteract the magnetic interference between the seawater medium and the ship's metal. Then, the magnetic field signal is regularized based on the attitude data. The heading deviation angle reflects the angle between the ship's heading and the cable's direction. The horizontal offset reflects the lateral engineering distance between the ship and the cable's centerline and has positive and negative values.

[0080] The control command generation module 6, based on data processing results, generates heading angular velocity commands through PID control laws and model reference adaptive strategies, and performs strategy processing such as amplitude limiting and dynamic adjustment. This module can run on an embedded controller (such as STM32, Pixhawk) or a host computer system to achieve closed-loop control of the ship's heading. The control command generation module 6 is located adjacent to the data processing module 5, in the same electromagnetically shielded compartment, and is equipped with an embedded controller. It supports online deployment of the control law model and is coupled with a processing unit to accelerate calculations. It receives deviation results from the high-speed interface receiving module 5 and then sends commands to the actuator 3 via the CANopen bus. The control command generation module 6 is electrically connected to the data processing module 5. Based on the data processing results, it generates heading angular velocity control commands for the ship according to a preset control law, and can perform command amplitude limiting and dynamic adjustment (including emergency strategies when horizontal deviation exceeds a threshold), achieving closed-loop control of the ship's heading.

[0081] Communication module 8 is used to upload sensor data, processing results, trajectory, and other information from the ship to the shore base station via a wireless link, supporting remote command issuance and status monitoring. The shipborne base station is located in the compartment at the bottom of the antenna mast in the superstructure of the ship, with high-gain antennas mounted at the top of the mast and the stern communication mast (dual-antenna diversity reception, strong wind resistance). The shipborne base station supports multi-mode communication, and the baseband processing unit has a built-in GNSS (Global Navigation Satellite System) dual-mode receiver, which interacts bidirectionally with the data processing module 5 via a gigabit Ethernet interface. It is responsible for uploading data to the shore base and receiving shore base commands, and is powered by the power module 9 through a dedicated adapter.

[0082] Data storage module 7 stores the collected raw magnetic field data, attitude, position, and control commands locally (e.g., via SD card, USB flash drive) for subsequent analysis, debugging, and archiving. An independent temperature-controlled data compartment is located in the middle of the ship, employing an industrial-grade solid-state drive array configured in RAID 1 for redundancy and backup, supporting health monitoring. It connects to data processing module 5 via a high-speed interface, storing the entire process information in real time, and is powered by power module 9 via a converter.

[0083] Power module 9 is a marine-grade DC uninterruptible power supply (UPS), supporting multiple inputs and battery backup power, forming a hierarchical power distribution architecture to power various core modules and terminal equipment. Power module 9 is located in the stern power compartment (fireproof and moisture-proof, equipped with safety monitoring and fire extinguishing devices), and directly powers core equipment such as module actuator 3, data processing module 5, data storage module 7, and communication module 8. These core modules then provide secondary power to other terminal equipment, forming a hierarchical architecture that balances reliability and simplified wiring. Figure 2 To clearly show the data flow, the power module is not displayed. This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0084] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0085] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A detection method for a surface vessel dual-sensor submarine cable route detection system, characterized in that, Includes the following steps: S1, calibrate the dual triaxial magnetometer, calibrate the attitude sensor, and complete signal link testing and algorithm pre-verification; S2, based on historical data or S-shaped path detection, locate the submarine cable position and determine the initial waypoint; S3 uses the magnetic field sensing component to collect high-frequency magnetic field data at the beginning and end as the raw magnetic field signal, the attitude sensing unit to collect attitude data, the positioning system module to obtain position and heading information, and the UTC timestamp synchronization mechanism to achieve time alignment of all data. S4. The original magnetic field signal is regularized using attitude data to obtain regularized magnetic field data. The Taylor-Lorentz equation is used to process the regularized magnetic field data, and the heading deviation angle and horizontal offset of the ship relative to the submarine cable are calculated. S5, Based on the heading deviation angle and horizontal offset, control commands for the ship's heading angular velocity and heading are generated according to the PID control law combined with the model reference adaptive strategy; S6 collects electromagnetic signals and updates parameters in real time, repeating S3-S5 to achieve continuous submarine cable route tracking.

2. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, In S4, the regularization process is as follows: receiving the heading angle, pitch angle and roll angle from the attitude sensor, and completing the transformation between the geocentric coordinate system and the ship coordinate system through a rotation matrix to obtain regularized magnetic field data.

3. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, In S4, the Taylor-Lorentz equation is: Where: A is the effective magnetic field strength after the TL equation correction, which is a three-axis vector data; The data represents the regularized magnetic field; X is the direction cosine matrix of the TL compensation model, calculated from the heading angle, pitch angle, and roll angle; the... This is the compensation coefficient vector for the TL equation.

4. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, In S4, the calculation process of the heading deviation angle and horizontal offset is as follows: electromagnetic induction data is extracted from the regularized magnetic field data, and after processing by the arctangent function, the heading deviation angle of the ship relative to the submarine cable is obtained. The horizontal offset is obtained by combining the installation distance of the bow and stern magnetometers, the electromagnetic induction data and the heading deviation angle.

5. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, In S5, the heading angular velocity The calculation formula is: in: As a proportionality coefficient The integral coefficient is... These are differential coefficients. This is the scaling factor for the horizontal offset. Let t be the heading deviation angle and t be time.

6. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 5, characterized in that, S5 also includes a limiting process for the generated heading angular velocity control command, restricting the value range of the heading angular velocity control command to [-10° / s, 10° / s].

7. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, In S5, a standard second-order model is used to construct the target heading behavior as the ideal desired heading trajectory; the heading tracking error and its rate of change between the ship's actual heading and the ideal desired heading trajectory are calculated; based on the heading tracking error and its rate of change, the PID control parameters are updated online adaptively. The formula for calculating the ideal desired heading trajectory is: in, Let be the transfer function of the second-order reference model, and s be the Laplace operator. The system's natural frequency. The damping ratio is denoted as .

8. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, S5 also includes a preset horizontal offset threshold. When the horizontal offset does not exceed the threshold, control commands are generated according to the conventional PID control law. When the horizontal offset exceeds the threshold, an emergency adjustment strategy is triggered. The heading angular velocity control commands are limited.

9. The detection method of a surface vessel dual-sensor submarine cable route detection system according to claim 1, characterized in that, It also includes the actual cable path calculation step. Based on the calculated heading deviation angle and horizontal offset, combined with the ship's real-time latitude and longitude, the relative position deviation between the ship and the cable is converted into the absolute latitude and longitude coordinates of the cable through the geographic coordinate projection conversion formula. The trajectory is fitted by cubic spline interpolation method for multiple sets of real-time latitude and longitude coordinates of the cable calculated during continuous tracking to obtain the actual cable path.

10. A dual-sensor submarine cable route detection system for surface vessels, characterized in that, include: The magnetic field sensing component includes two sets of triaxial magnetometers, which are used to synchronously collect spatial vector information of the magnetic field around the submarine cable to obtain raw magnetic field data. Attitude sensing unit, including attitude sensors, is used to measure the spatial attitude of the ship in real time; The positioning system module is used to acquire the ship's geographical location information and geographical heading information; The data processing module is used to regularize the original magnetic field signal using attitude data to obtain regularized magnetic field data, process the regularized magnetic field data using the Taylor-Lorentz equation, and calculate the heading deviation angle and horizontal offset of the ship relative to the submarine cable. The control command generation module is used to generate control commands for the ship's heading angular velocity and heading based on the heading deviation angle and horizontal offset, according to the PID control law combined with the model reference adaptive strategy. An actuator is used to receive the heading angular velocity control command and drive the ship to complete the adjustment of heading angular velocity and heading.

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