Monitoring system and method for underwater long cable complex space three-dimensional attitude reconstruction

Abstract

The application provides a monitoring system and method for underwater long cable complex space three-dimensional posture reconstruction, comprising a long cable body, a monitoring system and a signal processing system. The long cable body presents different three-dimensional postures in different marine engineering applications and in a complex wave flow environment. The monitoring system comprises a plurality of sensors such as optical fiber strain sensors and MEMS posture sensors and is integrated in the long cable structure to monitor physical quantities such as strain, Euler angle, acceleration and depth at each position of the long cable. The signal processing system synchronously receives each physical quantity signal of the monitoring system, reconstructs the space three-dimensional shape of the long cable based on the strain, Euler angle, acceleration and depth signals and realizes real-time perception of the space three-dimensional posture of the long cable. The application can realize real-time perception of the posture of the long cable in a complex marine environment, monitor and display the three-dimensional shape and has a very wide application prospect in the field of marine engineering systems and equipment.

Description

Technical Field

[0001] This invention relates to the field of marine system monitoring technology, specifically to a monitoring system for complex three-dimensional attitude reconstruction of long underwater cables, applicable to real-time spatial three-dimensional attitude perception of ultra-thin long marine cables such as marine tow cables, underwater robot umbilical cables, and submarine cables. Background Technology

[0002] With the development of marine engineering in my country, long underwater cables have been widely used, including marine tow cables for exploration and signal acquisition, umbilical cables for connecting underwater robots, and offshore wind turbine cables. These long cables usually play an important role in collecting marine information and transmitting photoelectric signals. Under the excitation of ocean wave and current environment and dynamic boundary, they will exhibit complex three-dimensional spatial attitude. Accurately identifying the three-dimensional attitude of long cables, monitoring their working status, and avoiding entanglement or collision are of great significance for the normal operation of long cables.

[0003] In recent years, with the widespread application of marine pipelines and cables, their integrated monitoring systems have developed rapidly, and their online monitoring technology has become increasingly mature, with considerable successful application experience. Monitoring of marine flexible pipelines and cables mainly includes strain, Euler angles, acceleration, and pressure. Measurement technologies are divided into strain-based and motion-based methods, with strain-based sensors currently accounting for a large proportion. For traditional large-diameter marine flexible pipelines and cables, externally mounted clamps are often used to fix sensors to the cable surface to measure physical quantities at specific locations. However, the installation of these clamps affects the overall configuration of long, small-diameter cables. Therefore, fiber optic monitoring technology, with its advantages of long transmission distance, resistance to electromagnetic interference, stable performance, and small size, has been widely used in the marine pipeline and cable field. The reconstruction of complex three-dimensional cable shapes is essentially the reconstruction of three-dimensional curves, and the three-dimensional reconstruction algorithm affects the accuracy of position determination. Currently, three-dimensional curve reconstruction is mostly applied to short-distance, high-precision applications (typically less than 10m), mainly concentrated in medical surgical catheters. For shape measurement over distances at the kilometer level, its potential application is deformation monitoring of pipelines or submarine cables, but there are currently no mature monitoring methods or applications. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of this invention is to provide a monitoring system and method for reconstructing the three-dimensional attitude of long underwater cables in complex spaces.

[0005] A monitoring system for reconstructing the three-dimensional attitude of a long underwater cable in a complex space, provided by the present invention, is characterized in that it includes a long cable body, a monitoring system, and a signal processing system; The long cable body is a slender cylindrical structure. The top of the long cable is connected to a marine structure, and the end is a free or weakly constrained boundary condition. It has low bending stiffness and is prone to large deformation in complex wave and current environments, exhibiting a complex three-dimensional spatial posture. The monitoring system includes multiple sensors, which are integrated into the long cable structure using advanced manufacturing processes, and are used to monitor physical quantity signals at various locations on the long cable; the multiple sensors include at least an optical fiber strain sensor and a MEMS attitude sensor. The signal processing system is used to synchronously receive various physical quantity signals from the monitoring system, preprocess the physical quantity signals, and then reconstruct the signal to obtain the spatial three-dimensional shape of the long cable.

[0006] Preferably, the physical quantity signal includes strain and Euler angles; The multi-sensor also includes a pressure sensor and an acceleration sensor; Preferably, the fiber optic strain sensor can transmit strain signals from each measuring point in real time, and is integrated into the cross-sectional structure of the long cable in a four-point symmetrical orthogonal manner, embedded in the outer cladding surface of the long cable functional unit; The fiber optic strain sensor is surrounded by an outer sheath that covers the surface of the long cable and is parallel to the central axis of the long cable. Several measuring points are arranged along the axial direction of the long cable using a multi-threaded arrangement strategy, and the spacing between the measuring points is determined according to the dimensions of the long cable and the working conditions.

[0007] Preferably, the MEMS attitude sensor is capable of transmitting Euler angle signals at the corresponding position in real time, and is integrated into the outer sheath structure of the long cable, arranged at intervals along the axial direction of the long cable.

[0008] Preferably, the number and location of the multi-element sensors are determined by the length of the cable, the complexity of the wave flow environment, and the local curvature.

[0009] Preferably, the signal processing system includes a signal synchronization receiving module, a preprocessing module, and a three-dimensional attitude reconstruction module; The signal synchronization receiving module is used to receive the real-time time history of multi-dimensional physical quantity signals from each measuring point. The preprocessing module is used to filter the signals of each physical quantity and extract effective feature values; The three-dimensional attitude reconstruction module has a built-in reconstruction algorithm that calculates the spatial curvature and torsion at each measuring point based on strain data, and combines multivariate physical quantity constraints for correction to obtain the reconstructed three-dimensional shape of the long cable.

[0010] Preferably, the signal processing system also includes a visualization module for visualizing the reconstructed three-dimensional pose.

[0011] Preferably, the MEMS attitude sensor is arranged at a density of 1 sensor for every 50 fiber optic measurement points.

[0012] According to the present invention, a monitoring method for a monitoring system for complex three-dimensional attitude reconstruction of underwater long cables is provided, the monitoring method comprising: Step 1: Integrate the multi-sensor system of the monitoring system into the long cable body according to the preset method, and complete the connection and deployment between the long cable body and the marine structure; Step 2: After the monitoring system is started, the multi-sensor starts to collect data. Among them, the fiber optic strain sensor collects the strain signals of each measuring point on the long cable in real time, and the MEMS attitude sensor collects the Euler angle physical quantity signal synchronously. Step 3: The signal processing system synchronously receives signals from each sensor, filters the signals, and extracts effective feature values; Step 4: Based on the preprocessed strain data, calculate the spatial curvature and torsion at each measuring point of the long cable; Step 5: Combining the multivariate physical quantities collected in Step 2, constrain the overall spatial attitude of the long cable, calculate and correct the three-dimensional shape, and complete the reconstruction.

[0013] Preferably, the multi-sensor further includes a pressure sensor and an acceleration sensor; The monitoring method also includes a visualization step: the spatial three-dimensional attitude of the long cable is displayed in real time through the visualization module of the signal processing system.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention can monitor the complex spatial attitude of long underwater cables such as marine tow cables, umbilical cables connecting underwater robots, and offshore wind turbine cables online, and realize real-time perception and display.

[0015] 2. This invention can monitor multiple physical parameters such as strain, Euler angle, and acceleration of underwater long cables, providing more reference information for the reconstruction of the complex three-dimensional attitude of underwater long cables.

[0016] 3. This invention can reconstruct the three-dimensional spatial shape of underwater long cables with high precision. In the algorithm for reconstructing the complex three-dimensional attitude of underwater long cables, the strain of the long cable is combined with multi-dimensional physical parameters such as Euler angles. The local spatial curvature and torsion of the long cable are solved by the strain parameters of each measuring point, thereby realizing the three-dimensional spatial attitude reconstruction of the long cable. The overall attitude of the long cable is constrained by physical parameters such as Euler angles, which avoids the problem of error multiplication caused by excessive distance in common three-dimensional shape reconstruction.

[0017] 4. This invention is highly feasible, more closely aligned with engineering needs, and meets the requirements of actual marine engineering projects. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall system of the present invention; Figure 2This is a schematic diagram of the integration of the fiber optic strain sensor of the present invention with the cross-section of a long cable; Figure 3 This is a schematic diagram of the integration of the MEMS attitude sensor and the cross-section of a long cable according to the present invention; Figure 4 This is a schematic diagram of the fiber optic strain sensor of the present invention arranged along the axial direction of a long cable; Figure 5 This is a schematic diagram of the MEMS attitude sensor of the present invention arranged along the axial direction of the long cable; Figure 6 This is a schematic diagram showing the relationship between the curvature and the bending direction angle of the umbilical cable at the axial arc length position in this invention.

[0019] The components include: 1. Long cable body; 2. Fiber optic strain sensor; 3. MEMS attitude sensor; 4. Signal processing system. Detailed Implementation

[0020] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0021] This invention comprises a long cable body, a monitoring system, and a signal processing system. The long cable body exhibits different three-dimensional attitudes in various marine engineering applications and in complex wave and current environments. The monitoring system includes multiple sensors such as fiber optic strain sensors and MEMS attitude sensors, integrated into the long cable structure, for monitoring physical quantities such as strain, Euler angle, acceleration, and depth at various locations on the long cable. The signal processing system synchronously receives the signals of various physical quantities from the monitoring system, and reconstructs the spatial three-dimensional shape of the long cable based on signals such as strain, Euler angle, acceleration, and depth, thereby realizing real-time perception of the spatial three-dimensional attitude of the long cable.

[0022] The present invention provides a monitoring system for complex three-dimensional attitude reconstruction of long underwater cables, comprising a long cable body, a monitoring system, and a signal processing system.

[0023] The long cable body exhibits different three-dimensional postures in various marine engineering applications and under complex wave and current environments. The long cable body is a slender cylindrical structure. The top of the long cable is connected to a marine structure, and the end is subject to free or weakly constrained boundary conditions. The long cable itself has low bending stiffness and is prone to large deformations under complex wave and current environments, exhibiting complex three-dimensional spatial postures.

[0024] The monitoring system includes multiple sensors such as fiber optic strain sensors and MEMS attitude sensors, which are integrated into the long cable structure using advanced manufacturing processes to monitor physical quantities such as strain and Euler angles at various locations on the long cable.

[0025] The fiber optic strain sensor can transmit strain signals from each measuring point in real time. It is integrated into the cross-sectional structure of the long cable in a four-point symmetrical orthogonal manner, embedded in the outer cladding surface of the long cable functional unit. The fiber optic strain sensor is surrounded by an outer sheath covering the surface of the long cable. The fiber optic strain sensor is parallel to the central axis of the long cable, and several measuring points are arranged along the cable's axial direction. A multi-threaded fiber optic arrangement strategy improves the fault tolerance and robustness of strain measurement, reduces the impact of local measuring point failures on remaining measuring points, and transmits strain signals from each measuring point in real time. The multi-threaded fiber optic arrangement strategy includes: the fiber optics are arranged in a four-point orthogonal symmetrical manner; the spacing between grating measuring points comprehensively considers attitude reconstruction speed and reconstruction accuracy; and the measuring point spacing is determined according to different cable lengths and specific operating conditions. For example, for kilometer-long catenary cables, due to their long size and relatively simple shape, the measuring point spacing is larger, approximately 1m. For hundred-meter-long ROV umbilical cables, due to the potential for more complex cable shapes as the boundary moves, the measuring point spacing is correspondingly reduced, approximately 0.3m.

[0026] The MEMS attitude sensor can transmit Euler angle signals at the corresponding position in real time. It is integrated into the outer sheath structure of the long cable, with several measuring points arranged along the cable's longitudinal axis, for example, one MEMS attitude sensor is arranged for every 50 fiber optic measuring points. The multi-element sensor may also include pressure sensors, acceleration sensors, etc., the specific type of which is usually selected by the user. The number and placement of the fiber optic strain sensor, acceleration sensor, and other multi-element micro-sensors are determined by the length of the long cable and the wave and current environment. If the wave and current environment is complex, it may result in a more complex cable shape, and the number of sensors should be increased accordingly. If the curvature of a section of the long cable is large, such as a long cable with a gentle wave, the number of sensors can be appropriately increased in certain areas. The fiber optic strain sensor is integrated into the cross-sectional structure of the long cable in a four-point symmetrical orthogonal manner, embedded in the outer cladding surface of the long cable's functional unit, while the acceleration sensor and other multi-element micro-sensors are embedded in the outer sheath of the long cable.

[0027] The signal processing system can synchronously receive various physical quantity signals from the monitoring system, preprocess the physical quantity signals, and then reconstruct the spatial three-dimensional shape of the long cable based on signals such as strain and Euler angles. The signal processing system includes a long cable spatial three-dimensional shape reconstruction algorithm and a visualization display of the reconstructed three-dimensional attitude, thereby achieving real-time perception of the long cable's spatial three-dimensional attitude. Specifically, it synchronously acquires and receives various physical quantity signals from the monitoring system, including the signal history from multiple sensors such as strain measurement points and Euler angle measurement points distributed along the long cable's axis. The preprocessing of each physical quantity signal involves filtering and extracting effective feature values. The long cable spatial three-dimensional shape reconstruction uses the preprocessed physical quantity signals and strain data at the measurement points to calculate the spatial curvature and torsion at each measurement point. Further combining this with multiple physical quantities such as Euler angles, it constrains the underwater long cable's spatial attitude, performing spatial three-dimensional shape calculation and correction to obtain a high-precision long cable spatial three-dimensional shape. The visualization of the long cable's three-dimensional shape displays the reconstruction result in a three-dimensional shape, achieving real-time perception and visualization of the three-dimensional state.

[0028] The number and location of the multi-sensor array in the monitoring system can be adjusted according to the dimensions of the long cable and its environment. The accuracy of the three-dimensional shape reconstruction result is closely related to the number and location of the sensor measurement points, and it is necessary to comprehensively consider the reconstruction accuracy requirements, the feasibility of the sensor array, and the economy.

[0029] Furthermore, the specific implementation of the present invention is described below with reference to the accompanying drawings: according to Figure 1 As shown, this invention provides a monitoring system for reconstructing the complex three-dimensional attitude of an underwater long cable, comprising a long cable body, a monitoring system, and a signal processing system. Specifically: the long cable body 1 exhibits different three-dimensional attitudes in different marine engineering applications and under complex wave and current environments; the monitoring system includes multiple sensors 3 such as fiber optic strain sensors 2 and MEMS attitude sensors, integrated into the long cable structure using advanced manufacturing processes, for monitoring physical quantities such as strain and Euler angles at various locations on the long cable; the signal processing system 4 can synchronously receive the physical quantity signals from the monitoring system, filter the physical quantity signals, and then reconstruct the spatial three-dimensional shape of the long cable based on signals such as strain and Euler angles, wherein the signal processing system includes a long cable spatial three-dimensional shape reconstruction algorithm; the signal processing system 4 also includes a visualization display of the reconstructed three-dimensional attitude, thereby achieving real-time perception of the spatial three-dimensional attitude of the long cable.

[0030] according to Figure 2As shown, the monitoring system integrates the fiber optic strain sensor 2 into the cross-section of the long cable body 1. The fiber optic strain sensor 2 is integrated and installed along the cross-section of the long cable 1 in a four-point symmetrical orthogonal manner. The fiber optic strain sensor 2 is embedded in the outer sheath of the functional unit of the long cable 1. The outer sheath of the fiber optic strain sensor 2 is an outer sheath, which covers the surface of the long cable 1.

[0031] according to Figure 3 As shown, the monitoring system integrates multiple sensors 3, such as MEMS attitude sensors, into the cross-section of the long cable body 1, including but not limited to acceleration sensors, pressure sensors, tilt sensors, etc. The specific sensor type is usually selected by the user.

[0032] according to Figure 4 As shown, the fiber optic strain sensor 2 is arranged parallel to the central axis of the long cable 1. The fiber optic strain sensor 2 has strain measurement points spaced apart along the axial direction of the long cable 1. The multi-threaded fiber arrangement strategy improves the fault tolerance and robustness of strain measurement, reduces the impact of local measurement point failure on the remaining measurement points, and transmits the strain signals of each measurement point in real time.

[0033] according to Figure 5 As shown, the MEMS attitude sensor and other multi-element micro-sensors 3 are arranged at intervals along the axial direction of the long cable 1; the number and position of the fiber optic strain sensor 2, acceleration and other multi-element micro-sensors 3 in the monitoring system are determined by the length of the long cable 1 and the wave and current environment in which it is located.

[0034] In the specific implementation process, such as Figure 1 The overall system shown has a long cable 1 exhibiting a three-dimensional attitude under complex excitation. Multiple sensors 3, such as fiber optic strain sensor 2 and MEMS attitude sensor, collect signals at each measuring point in real time. The signal processing system 4 processes the strain and multiple physical quantities in real time, and calculates the three-dimensional shape of the long cable in real time by combining the embedded spatial reconstruction algorithm, and realizes the visualization of the three-dimensional shape of the long cable.

[0035] The present invention aims to provide a monitoring system for reconstructing the three-dimensional attitude of long underwater cables in complex spaces, so as to realize the real-time perception of the spatial attitude of long underwater cables in complex wave and current environments, avoid collisions or entanglements of long cables, and ensure the normal operation of long cables.

[0036] According to the present invention, a monitoring method based on the monitoring system for complex three-dimensional attitude reconstruction of underwater long cables is provided, the monitoring method comprising: Step 1: Integrate the multi-sensor system of the monitoring system into the long cable body according to the preset method, and complete the connection and deployment between the long cable body and the marine structure.

[0037] Step 2: After the monitoring system is started, the fiber optic strain sensor collects the strain signals of each measuring point on the long cable in real time, while the MEMS attitude sensor and other sensors simultaneously collect physical quantity signals such as Euler angle, acceleration, and depth.

[0038] Step 3: The signal processing system synchronously receives signals from each sensor, filters the signals, and extracts effective feature values.

[0039] Step 4: Based on the preprocessed strain data, calculate the spatial curvature and torsion at each measuring point on the long cable. For example... Figure 6 As shown, the right side represents the arc length along the umbilical cable axis. Curvature at location and the corresponding bending direction angle Based on the relationship between strain and curvature, arc length The strain information at each point can be further expressed as:

[0040] In the formula, Position of arc length First Strain values ​​at each point Where is the cross-sectional radius, Position of arc length Strain caused by axial tension Position of arc length The strain caused by torsion.

[0041]

[0042] Among them, the strain at four points on the same cross section is known, because If a matrix is ​​not square and its columns are in full order, then it has a left inverse matrix. Furthermore:

[0043] From this equation, the curvature at the corresponding arc-length section can be further solved. Torque and bending direction angle .

[0044] make , Then we have:

[0045]

[0046] Define three spatial vectors: tangent vector Normal vector binormal vector The three vectors have the following differential relationship:

[0047] Based on this differential relationship, the tangent direction at each measuring point can be obtained by iteratively calculating each point.

[0048] Step 5: Combining Euler angles, acceleration and other multi-dimensional physical quantities, constrain the overall spatial attitude of the long cable, calculate and correct the three-dimensional shape, and complete the high-precision reconstruction.

[0049] Step 6: Display the spatial three-dimensional attitude of the long cable in real time through the visualization module of the signal processing system.

[0050] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0051] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A monitoring method for a monitoring system for underwater long cable complex spatial three-dimensional attitude reconstruction, characterized in that, The monitoring method includes: Step 1: Integrate the multi-sensor system of the monitoring system into the long cable body according to the preset method, and complete the connection and deployment between the long cable body and the marine structure; Step 2: After the monitoring system is started, the multi-sensor starts to collect data. Among them, the fiber optic strain sensor collects the strain signals of each measuring point on the long cable in real time, and the MEMS attitude sensor collects the Euler angle physical quantity signal synchronously. Step 3: The signal processing system synchronously receives signals from each sensor, filters the signals, and extracts effective feature values; Step 4: Based on the preprocessed strain data, calculate the spatial curvature and torsion at each measuring point of the long cable; Step 4 includes: Based on the relationship between strain and curvature, arc length The strain information at each point is represented as follows: In the formula, Position of arc length First Strain values ​​at each point Where is the cross-sectional radius, Position of arc length Strain caused by axial tension Position of arc length The strain caused by torsion. Indicates the arc length along the umbilical cable axis Curvature at the location The arc length along the umbilical cable axis The bending direction angle corresponding to the location; Among them, the strain at four points on the same cross section is known, because If a matrix is ​​not square and its columns are in full order, then it has a left inverse matrix. Furthermore: From this equation, the curvature at the corresponding arc-length section can be further solved. Torque and bending direction angle ; make , Then we have: Define three spatial vectors: tangent vector Normal vector binormal vector The three vectors have the following differential relationship: Based on this differential relationship, the tangent direction at each measuring point can be obtained iteratively point by point; Step 5: Combining the multivariate physical quantities collected in Step 2, constrain the overall spatial attitude of the long cable, calculate and correct the three-dimensional shape, and complete the reconstruction.

2. The monitoring method of the monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 1, characterized in that, The multi-sensor also includes a pressure sensor and an acceleration sensor; The monitoring method also includes a visualization step: the spatial three-dimensional attitude of the long cable is displayed in real time through the visualization module of the signal processing system.

3. A monitoring system for reconstructing the three-dimensional attitude of long underwater cables in complex spaces, characterized in that, The system for implementing the monitoring method according to claim 1 or 2 includes a long cable body, a monitoring system, and a signal processing system; The long cable body is a slender cylindrical structure. The top of the long cable is connected to a marine structure, and the end is a free or weakly constrained boundary condition. It is prone to large deformation in complex wave and current environments, exhibiting a complex three-dimensional spatial posture. The monitoring system includes multiple sensors, which are integrated into the long cable structure using advanced manufacturing processes, and are used to monitor physical quantity signals at various locations on the long cable; the multiple sensors include at least an optical fiber strain sensor and a MEMS attitude sensor. The signal processing system is used to synchronously receive various physical quantity signals from the monitoring system, preprocess the physical quantity signals, and then reconstruct the signal to obtain the spatial three-dimensional shape of the long cable.

4. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 3, characterized in that, The physical quantity signals include strain and Euler angles; The multi-sensor also includes a pressure sensor and an acceleration sensor.

5. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 3, characterized in that, The fiber optic strain sensor can transmit strain signals from each measuring point in real time. It is integrated into the cross-sectional structure of the long cable in a four-point symmetrical orthogonal manner and embedded in the outer cladding surface of the long cable functional unit. The fiber optic strain sensor is surrounded by an outer sheath that covers the surface of the long cable and is parallel to the central axis of the long cable. Several measuring points are arranged along the axial direction of the long cable using a multi-threaded arrangement strategy, and the spacing between the measuring points is determined according to the dimensions of the long cable and the working conditions.

6. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 3, characterized in that, The MEMS attitude sensor can transmit Euler angle signals at the corresponding position in real time. It is integrated into the outer sheath structure of the long cable and arranged at intervals along the axial direction of the long cable.

7. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 3, characterized in that, The number and location of the multi-element sensors are determined by the length of the cable, the complexity of the wave flow environment, and the local curvature.

8. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 3, characterized in that, The signal processing system includes a signal synchronization receiving module, a preprocessing module, and a three-dimensional attitude reconstruction module; The signal synchronization receiving module is used to receive the real-time time history of multi-dimensional physical quantity signals from each measuring point. The preprocessing module is used to filter the signals of each physical quantity and extract effective feature values; The three-dimensional attitude reconstruction module has a built-in reconstruction algorithm that calculates the spatial curvature and torsion at each measuring point based on strain data, and combines multivariate physical quantity constraints for correction to obtain the reconstructed three-dimensional shape of the long cable.

9. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 8, characterized in that, The signal processing system also includes a visualization module for visualizing the reconstructed 3D pose.

10. The monitoring system for complex three-dimensional attitude reconstruction of underwater long cables according to claim 6, characterized in that, The MEMS attitude sensor is arranged at a density of 1 sensor for every 50 fiber optic measurement points.

Images