Ship profile dynamic generation method and device based on Beidou positioning data

Abstract

The present application relates to the technical field of ship navigation and intelligent monitoring, and specifically discloses a ship contour dynamic generation method and device based on Beidou positioning data, which comprises: acquiring ship static design parameters, deploying a multi-modal sensing network to collect real-time sensing data, determining whether to enter an extreme attitude state based on the ship static design parameters and the real-time sensing data, generating a feature point global coordinate set of the ship if it is determined not to enter the extreme attitude state, constructing a wave load model to calculate a dynamic bending moment distribution vector and predict deformation trend data of the ship hull if it is determined to enter the extreme attitude state, performing dynamic offset compensation based on the dynamic bending moment distribution vector and the deformation trend data in combination with the real-time sensing data to generate a compensated feature point global coordinate set of the ship, and generating a real-time ship contour model based on the feature point global coordinate set or the compensated feature point global coordinate set to realize high-precision and full-condition dynamic contour reconstruction of the ship.

Description

Technical Field

[0001] This invention relates to the field of ship navigation and intelligent monitoring technology, specifically to a method and apparatus for dynamically generating ship outlines based on BeiDou positioning data. Background Technology

[0002] With the development of intelligent shipping, the accurate generation of real-time three-dimensional ship profiles has become a core requirement for ship driving assistance, collision avoidance decision-making, structural health monitoring, and the construction of digital twin systems. Traditional ship positioning technology mainly relies on global navigation satellite system receivers to obtain single-point positions and combines attitude sensors to calculate ship motion. However, its core assumption is to simplify the ship hull as an ideal rigid body and ignore the elastic deformation of the hull structure under wave loads.

[0003] In practical engineering applications, technicians have identified the following prominent issues: First, in harsh inland waterway conditions, the vertical deflection of flexible hulls such as large container ships and oil tankers in a mid-arched or sag state can reach meters. The contour model based on the rigid body assumption deviates significantly from the actual shape of the ship, directly leading to distortion of the digital twin system and increased collision avoidance decision-making errors. Second, existing technologies have perception blind spots. BeiDou or global navigation satellite system terminals can only be deployed at a limited number of feature points, making it impossible to directly acquire deformation information of the continuous surface of the hull. Relying solely on strain sensors makes it difficult to map local deformation to the global geographic coordinate system. In addition, there is a lack of a unified spatiotemporal reference among multi-source sensors. BeiDou positioning data, attitude data, and strain data are often collected independently, with asynchronous time and inconsistent coordinate systems, leading to additional errors during data fusion.

[0004] Therefore, there is an urgent need for a method to dynamically generate ship profiles that integrates BeiDou high-precision positioning, attitude perception and structural strain monitoring, and corrects elastic deformation based on real-time wave loads, so as to achieve accurate reconstruction of ship digital models under all working conditions.

[0005] To address the above problems, this invention proposes a method and apparatus for dynamically generating ship outlines based on BeiDou positioning data. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for dynamically generating ship outlines based on BeiDou positioning data, so as to solve the aforementioned background problems.

[0007] The objective of this invention can be achieved through the following technical solution: a method for dynamically generating ship contours based on BeiDou positioning data, comprising the following steps:

[0008] Obtain ship static design parameters and deploy a multimodal sensor network to collect real-time sensing data;

[0009] Based on the ship's static design parameters and real-time sensing data, it is determined whether the ship has entered an extreme attitude state. If it has not, a global coordinate set of the ship's feature points is generated.

[0010] If it enters, construct a wave load model to calculate the dynamic bending moment distribution vector and predict the deformation trend data of the hull;

[0011] Based on dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, dynamic offset compensation is performed to generate a global coordinate set of compensation feature points for the ship.

[0012] A real-time ship contour model is generated based on the global coordinate set of feature points or the compensated global coordinate set of feature points.

[0013] Furthermore, the ship's static design parameters and real-time sensing data include:

[0014] Define a ship coordinate system, taking the ship's center of gravity as the origin, with the longitudinal axis pointing to the bow, the transverse axis pointing to the port side, and the vertical axis perpendicular to the deck and upward. The ship's static design parameters include the ship's main dimensions, the ship's three-dimensional hull lines, the theoretical three-dimensional coordinates of the ship's feature points in the ship coordinate system, and structural mechanical parameters. The ship's main dimensions include the ship's length, beam, and depth, while the structural mechanical parameters include the distribution of the elastic modulus of the hull beams along the longitudinal direction, the distribution of the moment of inertia in the cross section, and the structural stiffness matrix.

[0015] Real-time sensing data includes BeiDou positioning data, attitude and motion data, and deformation monitoring data. Among them, BeiDou positioning data includes the measured three-dimensional coordinates and positioning status of each ship feature point in the geocentric coordinate system, attitude and motion data includes six-degree-of-freedom motion parameters, and deformation monitoring data includes the longitudinal strain value of the hull and the deflection curve data based on the second integral solution of strain.

[0016] Furthermore, the method for determining whether an extreme posture state has been entered is as follows:

[0017] The deformation monitoring data includes deflection curve data. The peak points on the deflection curve data are extracted to obtain the maximum deflection value. The ratio of the maximum deflection value to the ship length, which is included in the static design parameters, is calculated to obtain the deformation ratio. The wave observation system is connected to obtain the current inland waterway information, including the effective wave height, wave direction, and wave period.

[0018] Define the extreme inland waterway condition identification conditions as follows: First, any six-degree-of-freedom motion parameter exceeds the corresponding preset extreme attitude threshold; second, the deformation ratio exceeds the preset deformation threshold; and third, the effective wave height exceeds the wave height limit corresponding to the ship's design inland waterway condition level. If any extreme inland waterway condition identification condition is met, the ship is determined to enter an extreme attitude state.

[0019] Furthermore, the method for generating the global coordinate set of feature points is as follows:

[0020] For ship feature points with a fixed positioning status, the absolute three-dimensional coordinates of the ship feature points in the geocentric coordinate system in the BeiDou positioning data are directly used to determine the global coordinates of the ship feature points. For ship feature points with undetermined status, a coordinate transformation calculation method is used to extract the determined global coordinates closest to the origin of the ship's coordinate system from the BeiDou positioning data as the ship's fixed reference points. Based on the ship's fixed reference points, the attitude and motion data are combined to process the data and obtain the global coordinates of each ship feature point in the geocentric coordinate system. All global coordinates are integrated to obtain the global coordinate group of the feature points.

[0021] Furthermore, the dynamic bending moment distribution vector is calculated as follows:

[0022] Based on the current inland waterway conditions, the wave phase distributed along the ship's length is calculated using the origin of the ship's coordinate system as the calculation reference point, combined with the ship's main dimensions and the current six-degree-of-freedom motion parameters.

[0023] The wave load model is based on potential flow theory combined with the three-dimensional hull profile for data simulation. An interpolation lookup table for wave pressure coefficient with respect to relative wave direction and wave period is established. The relative wave direction is the difference between the wave direction and the bow angle at the current moment. For the inland waterway conditions at the current moment, the wave pressure coefficient of the hull surface corresponding to the wave direction is looked up. Based on linear wave theory, the instantaneous wave pressure amplitude at each point on the hull surface is calculated according to the significant wave height and the wave pressure coefficient. The sign of the instantaneous wave pressure amplitude is determined according to the wave phase. The instantaneous wave pressure distribution on the hull surface is then obtained by integrating the data.

[0024] By retrieving structural mechanics parameters, the instantaneous wave pressure distribution on the hull surface is integrated along the ship's length to obtain the vertical wave shear force distribution along the ship's length. The vertical wave shear force is then integrated again along the ship's length to obtain the wave bending moment distribution along the ship's length. These are then combined to obtain the dynamic bending moment distribution vector.

[0025] Furthermore, the deformation trend data is obtained as follows:

[0026] Based on the bending theory of variable cross-section elastic beams, by substituting the wave bending moment and structural stiffness matrix of the structural mechanical parameters at the current moment, the static bending response curve of the hull under the current wave load is obtained. The static bending response curve represents the vertical deflection value distributed along the length of the ship. The maximum vertical deflection value and the corresponding longitudinal position of the hull bending upward and downward are extracted from the static bending response curve to obtain the mid-camber amplitude and mid-sag amplitude. The deformation trend data of the hull are then integrated.

[0027] Furthermore, the dynamic offset compensation method is as follows:

[0028] Using the current moment as a reference, the dynamic bending moment distribution vector, deformation trend data, and real-time sensing data are obtained as input data and synchronized in time.

[0029] The deflection curve data at the current moment is extracted from the real-time sensing data, and the static bending response curve predicted based on the dynamic bending moment distribution vector at the same moment is extracted from the deformation trend data. A complementary filtering strategy is adopted to weight and fuse the measured deflection on the deflection curve data and the vertical deflection value on the static bending response curve according to the preset fusion weight, so as to obtain the dynamic deflection curve composed of the fused deflection value.

[0030] If the fused deflection value of the dynamic deflection curve exceeds the preset large deformation threshold, a preset nonlinear correction coefficient is introduced to multiply the fused deflection value of the large deformation area of ​​the hull. The corrected dynamic deflection curve is discretized to the longitudinal position corresponding to each ship feature point, and the vertical dynamic offset of each ship feature point in the hull coordinate system is obtained. This offset is superimposed with the theoretical three-dimensional coordinates of the ship feature points to obtain the corrected instantaneous coordinates of the ship feature points in the hull coordinate system, thus completing the dynamic offset compensation.

[0031] Furthermore, the method for generating the global coordinate set of the compensated feature points is as follows:

[0032] The ship feature points with the fixed solution that are closest to the origin of the ship's coordinate system are extracted from the BeiDou positioning data and used as fixed reference points for the ship. The absolute three-dimensional coordinates of the ship's fixed reference points in the geocentric coordinate system are extracted. A real-time rotation matrix from the ship's coordinate system to the geocentric coordinate system is constructed based on attitude and motion data. For each ship feature point, the data is processed in combination with the corresponding corrected instantaneous coordinates of the ship's coordinate system to obtain the compensated global coordinates of the ship feature points in the geocentric coordinate system. The compensated global coordinate group of the feature points is then integrated.

[0033] Furthermore, the real-time ship profile model is generated as follows:

[0034] Based on the current extreme attitude state determination result, the corresponding feature point global coordinate group or the compensated feature point global coordinate group is selected as the input coordinate group. Based on the three-dimensional hull lines in the ship's static design parameters, a reference surface model of the hull profile is established. The input coordinate group is transformed to the measured position coordinates with the origin of the hull coordinate system as the reference. The radial basis function interpolation method is used to construct a continuous displacement field from the reference surface model to the measured position coordinates of each ship feature point. The measured position coordinates of the entire hull surface are discretized into point cloud data to generate a real-time ship profile model.

[0035] The device for dynamically generating ship contours based on BeiDou positioning data includes the following modules:

[0036] Data sensing module: acquires ship static design parameters and deploys a multimodal sensor network to collect real-time sensing data;

[0037] Extreme attitude determination and coordinate analysis module: Based on the ship's static design parameters and real-time sensing data, determine whether the ship has entered an extreme attitude state. If not, generate a global coordinate set of the ship's feature points.

[0038] Environmental and Deformation Analysis Module: If entered, it constructs a wave load model, calculates the dynamic bending moment distribution vector, and predicts the deformation trend data of the hull;

[0039] Offset compensation module: Based on dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, dynamic offset compensation is performed to generate a global coordinate group of compensation feature points of the ship.

[0040] Contour generation module: Generates a real-time ship contour model based on the global coordinate group of feature points or the compensated global coordinate group of feature points.

[0041] The beneficial effects of this invention are as follows:

[0042] 1. This invention is based on the multimodal deep fusion of Beidou positioning, attitude perception and structural strain. By constructing a wave load model to predict elastic deformation and combining it with measured deflection dynamic compensation, it breaks through the technical limitations of traditional rigid body assumptions. It accurately calculates meter-level deflection caused by hull arching and sagging under extreme inland waterway conditions, eliminates contour distortion, and provides high-precision dynamic data support for the dynamic generation of ship contours.

[0043] 2. This invention establishes an extreme attitude adaptive processing mechanism. In non-extreme states, the contour is quickly generated based on a fixed solution. In extreme states, the accuracy is ensured through dynamic offset compensation. Radial basis function interpolation is used to reconstruct discrete feature points into a continuous surface, realizing real-time and accurate mapping of the ship contour under all working conditions, and significantly improving the reliability of dynamic generation of the ship contour. Attached Figure Description

[0044] The invention will now be further described with reference to the accompanying drawings.

[0045] Figure 1 This is a flowchart illustrating the steps of the method for dynamically generating ship outlines based on BeiDou positioning data according to an embodiment of the present invention.

[0046] Figure 2 This is a module architecture diagram of the ship contour dynamic generation device based on Beidou positioning data described in an embodiment of the present invention. Detailed Implementation

[0047] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0048] Example 1

[0049] Please see Figure 1As shown in the embodiment of the present invention, the method for dynamic generation of ship contours based on BeiDou positioning data aims to solve the problems of existing ship positioning technologies that simplify the hull as a rigid body, ignore elastic deformation under extreme inland waterway conditions leading to contour distortion, and the difficulty of a single sensor to simultaneously handle global positioning and local deformation monitoring. The method achieves high-precision, all-condition dynamic ship contour reconstruction, specifically including the following steps:

[0050] S1: Obtain ship static design parameters and deploy a multimodal sensor network to collect real-time sensing data;

[0051] Specifically, define the ship's coordinate system as follows: select the ship's center of gravity as the origin, with the longitudinal axis pointing towards the bow, the transverse axis pointing towards the port side, and the vertical axis perpendicular to the deck and upwards;

[0052] The static design parameters of a ship are retrieved from the ship design database using the ship's unique identification number. The static design parameters include the ship's main dimensions, the three-dimensional hull lines, the theoretical three-dimensional coordinates of the ship's feature points in the hull coordinate system, and structural mechanical parameters. The ship's main dimensions include the ship's length, beam, and depth. The structural mechanical parameters include the distribution of the elastic modulus of the hull beams along the longitudinal direction, the distribution of the moment of inertia in the cross section, and the structural stiffness matrix.

[0053] Exemplary ship feature points include the bow post point, stern post point, side plating line inflection point, and deck edge feature point. It should be noted that the ship static design parameters provide the ship with a reference geometric model and mechanical constitutive relationship. The three-dimensional hull lines are stored in the form of a form value table, which describes the geometric shape of each section of the hull in the design state.

[0054] For ships, a multimodal sensor network is deployed, which includes a Beidou high-precision positioning terminal, an attitude sensor group and a fiber optic strain sensor array to collect real-time sensing data including Beidou positioning data, attitude and motion data and deformation monitoring data.

[0055] Among them, the Beidou high-precision positioning terminal is deployed at the ship's feature points. The terminal antenna installation position is precisely corresponding to the theoretical three-dimensional coordinates of the ship's feature points, and reinforcement and protection measures are taken to resist the influence of vibration environment. The Beidou high-precision positioning terminal collects and outputs the measured three-dimensional coordinates and corresponding positioning status of each ship's feature points in the geocentric and geofixed coordinate system, and integrates them to obtain Beidou positioning data.

[0056] It should be noted that the positioning status refers to the accuracy level and reliability indicator of the positioning data currently output by the Beidou high-precision positioning terminal, including fixed solution, floating-point solution, single-point solution, invalid solution or no solution, which is used to measure the credibility of the current location data.

[0057] The attitude sensor group is installed at the preset key structural parts of the hull. Each key structural part of the hull corresponds to an attitude sensor group that includes at least one high-precision inertial measurement unit, a multi-axis gyroscope and a three-axis accelerometer. The attitude sensor group collects and outputs the raw angular velocity and linear acceleration, and after navigation calculation, it obtains six degrees of freedom motion parameters, including roll angle, pitch angle, bow angle, heave displacement, sway displacement and pitch displacement, and integrates them to obtain attitude and motion data.

[0058] Exemplary key structural parts of the hull include the area near the bow anti-collision bulkhead, the strong frame in the cargo hold area midway, and the upper surface of the stern engine room platform. It should be noted that the attitude sensor group is used to sense the six degrees of freedom motion of the hull in real time, providing rotation matrices and translation vectors for the subsequent transformation of the hull's local coordinates to the global coordinate system.

[0059] Among them, the fiber optic strain sensor array is installed on the key section of the main longitudinal strong component of the hull. It is installed in pairs along the length of the ship according to the preset spacing and along the depth direction. The fiber optic strain sensor array collects and outputs the longitudinal strain value of the hull, and obtains the deflection curve data distributed along the length of the ship based on the second integral of the strain, and integrates them to obtain the deformation monitoring data.

[0060] Exemplary main longitudinal strong components of the hull include deck girder, bottom longitudinal girder, and side top plate. It should be noted that the longitudinal strain value of the hull represents the amount of expansion and contraction deformation per unit length of the hull structure measured along the length of the ship. It is used to quantify the degree of tension or compression that the hull bears under wave load. The deflection curve data represents the vertical displacement curve of each point on the centerline plane of the hull obtained by double integration of the longitudinal strain value of the hull along the length of the ship. It is used to describe the bending deformation of the hull in the mid-camber or mid-sag state.

[0061] Time synchronization and spatial coordinate system calibration are uniformly implemented for the deployed multimodal sensor network. Time synchronization adopts a precise time protocol to allocate a unified time reference for the multimodal sensor network, ensuring that each frame of real-time sensing data has a timestamp accurate to the microsecond level. Spatial coordinate system calibration determines the precise position coordinates and installation orientation of each sensor in the multimodal sensor network in the ship coordinate system. The transformation relationship from the sensor local coordinate system to the ship coordinate system is established through a pre-constructed coordinate transformation model. For the Beidou high-precision positioning terminal, the output three-dimensional coordinates in the geocentric geofixed coordinate system are mapped to the ship coordinate system through real-time differential correction and transformation parameters, ensuring that the real-time sensing data is unified under the same spatiotemporal reference.

[0062] S2: Based on the ship's static design parameters and real-time sensing data, determine whether the ship has entered an extreme attitude state. If not, generate a global coordinate set of the ship's feature points.

[0063] Specifically, the system accesses real-time sensing data collected by a multimodal sensor network at a fixed sampling rate, including BeiDou positioning data, attitude and motion data, and deformation monitoring data. The system also accesses a wave observation system in real time to obtain information on the current inland waterway conditions, including significant wave height, wave direction, and wave period. The wave observation system relies on shipborne wave radar to acquire information on inland waterway conditions.

[0064] Examples of real-time sensing data and inland waterway information are shown in the table below;

[0065] Table 1: Excerpt of real-time sensing data and inland waterway information (UTC time, 2025-08-15, 10:32:45.123).

[0066]

[0067] The attitude and motion data, including the six degrees of freedom motion parameters, are compared with the preset extreme attitude thresholds. The deformation monitoring data, including the deflection curve data, is obtained. The peak points on the deflection curve data are extracted to obtain the maximum deflection value. The ratio of the maximum deflection value to the ship length, which is included in the static design parameters, is calculated and compared with the preset deformation threshold.

[0068] It should be noted that the extreme attitude threshold and deformation threshold are determined based on the ship design stability curve, structural strength verification standards, and statistical analysis of historical navigation data. The ship design stability curve is a characteristic curve drawn during the design phase that reflects the relationship between the ship's restoring moment and the heel angle under different loading conditions. It is used to assess the ship's ability to resist capsizing. The structural strength verification standards are a set of specifications that stipulate the safety limits such as stress and deformation that the hull structure should meet under various working conditions, based on the ship's design and operation. Historical navigation data is a statistical set of measured information such as the track, inland waterway conditions, motion response, and structural response recorded by similar ships during navigation missions in the past pre-selected historical period.

[0069] The criteria for identifying extreme inland waterway conditions are defined as follows: first, any six-degree-of-freedom motion parameter exceeds the corresponding preset extreme attitude threshold; second, the deformation ratio exceeds the deformation threshold; and third, the effective wave height exceeds the wave height limit corresponding to the ship's design inland waterway condition level.

[0070] If any extreme inland waterway condition identification condition is met, it is determined that the extreme attitude state has been entered; otherwise, it is determined that the extreme attitude state has not been entered and the state is in a non-extreme attitude state.

[0071] It should be noted that under non-extreme attitude conditions, the ship profile can be directly generated based on the fusion of attitude and motion data from BeiDou positioning data. However, once it enters an extreme attitude state, elastic deformation becomes a non-negligible source of error, and a wave load model must be introduced for feedforward compensation.

[0072] If it is determined that the ship has not entered an extreme attitude state, the system executes the non-extreme attitude processing procedure to generate a global coordinate group of the ship's feature points.

[0073] Specifically, for the positioning status of each ship feature point corresponding to the BeiDou positioning data, for ship feature points with a fixed positioning status, the absolute three-dimensional coordinates of the ship feature points in the BeiDou positioning data in the geocentric coordinate system are directly used to determine the global coordinates of the ship feature points. After the global coordinates of ship feature points with a fixed positioning status are determined, for ship feature points with undetermined positioning status, the coordinate transformation calculation method is used to determine the global coordinates of the ship feature points.

[0074] The specific process of coordinate transformation calculation is as follows:

[0075] The BeiDou positioning data and attitude and motion data at the current moment are time-synchronized and verified to ensure timestamp alignment. The determined global coordinates closest to the origin of the ship's coordinate system are extracted from the BeiDou positioning data as the fixed reference point of the ship's hull. Based on the roll angle, pitch angle and bow angle in the attitude and motion data, a real-time rotation matrix from the ship's coordinate system to the geocentric coordinate system is constructed according to a predefined rotation order.

[0076] For each undetermined ship feature point in the ship's coordinate system, retrieve the theoretical three-dimensional coordinates of each undetermined ship feature point from the ship's static design parameters, calculate the position vector of each ship feature point relative to the fixed reference point of the ship's hull, transform the position vector to the geocentric coordinate system through a real-time rotation matrix, and add it to the global coordinates of the fixed reference point of the ship's hull to obtain the global coordinates of each ship feature point in the geocentric coordinate system. Integrate the global coordinates of all ship feature points to obtain the global coordinate group of feature points.

[0077] It should be noted that under non-extreme attitude conditions, the amplitude of elastic deformation of the hull is small and can be ignored. Therefore, the theoretical three-dimensional coordinates of the ship feature points are directly used for conversion, and the generated global coordinate set of feature points will be directly used for real-time ship contour generation.

[0078] It should be noted that the purpose of this step is to establish an extreme condition discrimination logic that integrates motion response, structural deformation and external environment, and to propose a feature point estimation method based on rigid body kinematics for non-extreme conditions. This ensures accuracy while avoiding complex calculations and enables adaptive switching of processing strategies.

[0079] S3: If it enters, construct a wave load model to calculate the dynamic bending moment distribution vector and predict the deformation trend data of the hull;

[0080] Specifically, based on the current inland waterway conditions, the origin of the ship's coordinate system is used as the calculation reference point. The wave phase distributed along the ship's length is calculated by combining the ship's main dimensions with the current six-degree-of-freedom motion parameters, including the bow angle. The real-time wave parameter vector is then established using the current inland waterway conditions as the input to the wave load model.

[0081] The wave load model is based on potential flow theory combined with the three-dimensional hull profile for data simulation. An interpolation lookup table for the wave pressure coefficient with respect to the relative wave direction and wave period is established. The wave pressure coefficient reflects the local amplification or attenuation effect of the hull geometry on the wave pressure at various points on the hull surface. The relative wave direction is the difference between the wave direction and the bow angle at the current moment. For the inland waterway conditions at the current moment, the wave pressure coefficient of the hull surface corresponding to the wave direction is looked up. Based on linear wave theory, the instantaneous wave pressure amplitude at various points on the hull surface is calculated according to the effective wave height and the wave pressure coefficient. The sign of the instantaneous wave pressure amplitude is determined according to the wave phase. The positive and negative signs represent the direction of the force on the hull, respectively. The instantaneous wave pressure distribution on the hull surface is obtained by integrating the results.

[0082] Structural mechanics parameters are retrieved from the ship's static design parameters, including the elastic modulus distribution and sectional moment of inertia distribution of the hull beams along the longitudinal direction. The wave load model integrates the instantaneous wave pressure distribution on the hull surface along the ship's length to obtain the vertical wave shear force distribution along the ship's length. After integrating the vertical wave shear force along the ship's length again, the wave bending moment distribution along the ship's length is obtained. The wave bending moment distribution along the ship's length is integrated into a dynamic bending moment distribution vector as the output of the wave load model.

[0083] It should be noted that vertical wave shear force refers to the resultant force perpendicular to the baseline direction generated at a certain cross section of the hull after integrating the wave pressure at various points along the length of the hull. It is used to describe the vertical shearing action borne by that cross section. Wave bending moment refers to the bending moment about the transverse axis generated at a certain cross section of the hull after integrating the vertical wave shear force again along the length of the hull. It is used to describe the degree of mid-camber or mid-sag bending deformation of the hull caused by wave load.

[0084] Based on the bending theory of variable cross-section elastic beams, by substituting the wave bending moment and structural stiffness matrix of the structural mechanical parameters at the current moment, the static bending response curve of the hull under the current wave load is obtained. The static bending response curve represents the vertical deflection value distributed along the length of the ship. The vertical deflection value represents the vertical displacement of the hull centerline plane relative to the baseline at each longitudinal position. The maximum vertical deflection values ​​of the hull bending upward and downward and their corresponding longitudinal positions are extracted to obtain the mid-camber amplitude and mid-sag amplitude. The deformation trend data of the hull are then integrated.

[0085] It should be noted that the mid-arch state is characterized by tension on the deck, compression on the bottom, and upward bending of the hull, while the sagging state is characterized by compression on the deck, tension on the bottom, and downward bending of the hull.

[0086] It should be noted that the purpose of this step is to introduce the potential flow theory in hydrodynamics and the bending theory of variable cross-section elastic beams in structural mechanics into real-time positioning calculation. By using the wave pressure coefficient interpolation table and bending moment integral, the prediction of hull deformation trend based on physical mechanism is realized, providing feedforward input for subsequent compensation.

[0087] S4: Based on the dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, dynamic offset compensation is performed to generate a global coordinate group of the ship's compensation feature points.

[0088] Specifically, after the system determines that it has entered an extreme attitude state, it uses the current moment as a reference to synchronously acquire dynamic bending moment distribution vector, deformation trend data and real-time perception data as input data. Deformation trend data includes static bending response curve, mid-arch amplitude and mid-sag amplitude. Real-time perception data includes Beidou positioning data, attitude and motion data and deformation monitoring data. The input data is time-synchronized and aligned, and the timestamp is checked to see if it falls within the same microsecond-level synchronization window. If it does not fall within the window, it is determined that there is a time offset. The timestamp is then unified to the same fusion moment by interpolation combined with cache alignment.

[0089] Dynamic offset compensation is performed based on the input data after time synchronization and alignment.

[0090] Specifically, the deflection curve data at the current moment is extracted from the deformation monitoring data, and the static bending response curve predicted based on the dynamic bending moment distribution vector at the same moment is extracted from the deformation trend data. A complementary filtering strategy is adopted to weight and fuse the measured deflection on the deflection curve data and the vertical deflection value on the static bending response curve according to the preset fusion weight to obtain the dynamic deflection curve.

[0091] It should be noted that the fusion weight is dynamically adjusted based on the current deformation ratio and inland river conditions. The larger the deformation ratio and the more severe the inland river conditions, the higher the fusion weight of the static bending response curve is, so as to give full play to the feedforward advantage of the wave load model. The smaller the deformation ratio and the more gentle the inland river conditions, the higher the fusion weight of the deflection curve data is, so as to highlight the true response of the deformation monitoring data.

[0092] The fused deflection value on the dynamic deflection curve is compared with the preset large deformation threshold. If the fused deflection value exceeds the preset large deformation threshold, it is determined to be a large deformation area of ​​the hull. A nonlinear correction coefficient is introduced to multiply the fused deflection value of the large deformation area of ​​the hull. The nonlinear correction coefficient is pre-calibrated based on deformation monitoring data through finite element simulation of pre-acquired typical large deformation conditions to ensure the compensation accuracy in the large deformation area of ​​the hull.

[0093] The corrected dynamic deflection curve is discretized to the longitudinal position corresponding to each ship feature point to obtain the vertical dynamic offset of each ship feature point in the hull coordinate system. The theoretical three-dimensional coordinates of the ship feature points are superimposed with the vertical dynamic offset to obtain the corrected instantaneous coordinates of the ship feature points in the hull coordinate system.

[0094] Transform the modified ship coordinate system instantaneous coordinates to the geocentric coordinate system;

[0095] Specifically, the ship feature points with the fixed solution closest to the origin of the ship's coordinate system are extracted from the BeiDou positioning data as fixed reference points for the ship. The absolute three-dimensional coordinates of the ship's fixed reference points in the geocentric coordinate system are extracted. The absolute three-dimensional coordinates already include the overall linear motion of the ship, which includes sway, roll, and heave. Based on the roll angle, pitch angle, and bow angle in the attitude and motion data, a real-time rotation matrix from the ship's coordinate system to the geocentric coordinate system is constructed according to a predefined rotation sequence. For each ship feature point, the position vector of the corresponding corrected instantaneous coordinates of the ship's coordinate system relative to the ship's fixed reference point is calculated. The position vector is transformed to the geocentric coordinate system through the real-time rotation matrix and then added to the absolute three-dimensional coordinates of the ship's fixed reference point to obtain the compensated global coordinates of the ship feature point in the geocentric coordinate system. The compensated global coordinate group of the feature points is then obtained.

[0096] It should be noted that the dynamic offset calculation provides accurate hull coordinate input for coordinate transformation, and the coordinate transformation maps rigid body motion and elastic deformation to the geocentric and geofixed coordinate system. The global coordinate group of the compensated feature points is used to generate the real-time ship profile.

[0097] It should be noted that this step involves adopting a hybrid compensation architecture of measured deformation feedback and wave load feedforward, and dynamically adjusting the fusion weight according to the severity of the inland river conditions. At the same time, nonlinear correction based on finite element simulation is introduced, which solves the limitations of linear elasticity theory in the large deformation region and significantly improves the contour reconstruction accuracy under extreme inland river conditions.

[0098] S5: Generate a real-time ship contour model based on the global coordinate group of feature points or the compensated global coordinate group of feature points;

[0099] Specifically, the system selects the corresponding global coordinate group of feature points or the compensated global coordinate group of feature points as the input coordinate group based on the determination result of the extreme attitude state at the current moment: if it is determined that the extreme attitude state has not been entered at the current moment, the global coordinate group of feature points is used; if it is determined that the extreme attitude state has been entered at the current moment, the compensated global coordinate group of feature points is used.

[0100] The input coordinate set contains the global coordinates of each ship feature point in the geocentric-solid coordinate system;

[0101] The real-time ship profile generation process is executed by combining the input coordinate set with the three-dimensional hull lines in the ship's static design parameters.

[0102] Based on the three-dimensional hull lines in the static design parameters of the ship, a reference surface model of the hull profile is established. The input coordinate set is used as a dynamic constraint condition to perform spatial transformation and local deformation adjustment on the reference surface model, generating a real-time ship profile that matches the current actual attitude and deformation of the ship.

[0103] Specifically, the input coordinate set is transformed into a local expression based on the origin of the ship's coordinate system, obtaining the measured position coordinates of each ship feature point relative to the origin of the ship's coordinate system at the current moment. A reference surface model is established using the three-dimensional hull profile as the initial template. The radial basis function interpolation method is used to construct a continuous displacement field from the reference surface model to the measured position coordinates of each ship feature point. The continuous displacement field ensures accurate matching of the measured position coordinates at the ship feature points, and achieves smooth transition in non-ship feature point areas through interpolation functions, thereby obtaining the measured position coordinates of the entire hull surface.

[0104] To meet the real-time visualization requirements of ship outlines, the measured position coordinates of the entire ship surface are discretized into point cloud data to generate a real-time ship outline model.

[0105] It should be noted that the real-time ship profile model includes the geometric shape of all outer plating, decks and major superstructures of the hull, and is marked with timestamps to ensure synchronization with real-time perception data. The generated real-time ship profile can not only be used for visualization display in the bridge to help the driver intuitively perceive the hull's motion and deformation state, but also be used as the core dynamic data of the ship's digital twin system based on the input coordinate set for the dynamic three-dimensional presentation of the ship in collision avoidance decision-making, berthing assistance and structural health assessment.

[0106] The technical solution of this invention is as follows: obtain the static design parameters of the ship, deploy a multimodal sensor network to collect real-time sensing data, determine whether the ship has entered an extreme attitude state based on the static design parameters and real-time sensing data, if not, generate a global coordinate set of the ship's feature points, if so, construct a wave load model to calculate the dynamic bending moment distribution vector and predict the deformation trend data of the hull, perform dynamic offset compensation based on the dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, generate a global coordinate set of compensated feature points of the ship, and generate a real-time ship contour model based on the global coordinate set of feature points or the global coordinate set of compensated feature points.

[0107] Example 2

[0108] Please see Figure 2As shown in the figure, the ship contour dynamic generation device based on Beidou positioning data described in this embodiment of the invention specifically includes the following modules:

[0109] Data sensing module: acquires ship static design parameters and deploys a multimodal sensor network to collect real-time sensing data;

[0110] Extreme attitude determination and coordinate analysis module: Based on the ship's static design parameters and real-time sensing data, determine whether the ship has entered an extreme attitude state. If not, generate a global coordinate set of the ship's feature points.

[0111] Environmental and Deformation Analysis Module: If entered, it constructs a wave load model, calculates the dynamic bending moment distribution vector, and predicts the deformation trend data of the hull;

[0112] Offset compensation module: Based on dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, dynamic offset compensation is performed to generate a global coordinate group of compensation feature points of the ship.

[0113] Contour generation module: Generates a real-time ship contour model based on the global coordinate group of feature points or the compensated global coordinate group of feature points.

[0114] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for dynamically generating ship contours based on BeiDou positioning data, characterized in that: Includes the following steps: Obtain ship static design parameters and deploy a multimodal sensor network to collect real-time sensing data; Based on the ship's static design parameters and real-time sensing data, it is determined whether the ship has entered an extreme attitude state. If it has not, a global coordinate set of the ship's feature points is generated. If it enters, construct a wave load model to calculate the dynamic bending moment distribution vector and predict the deformation trend data of the hull; Based on dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, dynamic offset compensation is performed to generate a global coordinate set of compensation feature points for the ship. A real-time ship contour model is generated based on the global coordinate set of feature points or the compensated global coordinate set of feature points.

2. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 1, characterized in that: Ship static design parameters and real-time sensing data include: Define a ship coordinate system, taking the ship's center of gravity as the origin, with the longitudinal axis pointing to the bow, the transverse axis pointing to the port side, and the vertical axis perpendicular to the deck and upward. The ship's static design parameters include the ship's main dimensions, the ship's three-dimensional hull lines, the theoretical three-dimensional coordinates of the ship's feature points in the ship coordinate system, and structural mechanical parameters. The ship's main dimensions include the ship's length, beam, and depth, while the structural mechanical parameters include the distribution of the elastic modulus of the hull beams along the longitudinal direction, the distribution of the moment of inertia in the cross section, and the structural stiffness matrix. Real-time sensing data includes BeiDou positioning data, attitude and motion data, and deformation monitoring data. Among them, BeiDou positioning data includes the measured three-dimensional coordinates and positioning status of each ship feature point in the geocentric coordinate system; attitude and motion data includes six-degree-of-freedom motion parameters; and deformation monitoring data includes the longitudinal strain value of the hull and the deflection curve data based on the second integral solution of strain.

3. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 2, characterized in that: The method for determining whether an extreme posture state has been entered is as follows: The deformation monitoring data includes deflection curve data. The peak points on the deflection curve data are extracted to obtain the maximum deflection value. The ratio of the maximum deflection value to the ship length, which is included in the static design parameters, is calculated to obtain the deformation ratio. The wave observation system is connected to obtain the current inland waterway information, including the effective wave height, wave direction, and wave period. The following conditions are defined for identifying extreme inland waterway conditions: First, any six-degree-of-freedom motion parameter exceeds the corresponding preset extreme attitude threshold; second, the deformation ratio exceeds the preset deformation threshold; and third, the effective wave height exceeds the wave height limit corresponding to the ship's design inland waterway condition level. If any one of the extreme inland waterway condition identification conditions is met, the ship is determined to enter an extreme attitude state.

4. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 2, characterized in that: The method for generating the global coordinate set of feature points is as follows: For ship feature points with a fixed positioning state, the absolute three-dimensional coordinates of the ship feature points in the geocentric coordinate system from the BeiDou positioning data are directly used to determine the global coordinates of the ship feature points. For ship feature points with undetermined positioning states, a coordinate transformation calculation method is used to extract the determined global coordinates closest to the origin of the ship's coordinate system from the BeiDou positioning data as the ship's fixed reference points. Based on the ship's fixed reference points and attitude and motion data, data processing is performed to obtain the global coordinates of each ship feature point in the geocentric coordinate system. All global coordinates are integrated to obtain the global coordinate group of the feature points.

5. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 3, characterized in that: The dynamic bending moment distribution vector is calculated as follows: Based on the current inland waterway conditions, the wave phase distributed along the ship's length is calculated using the origin of the ship's coordinate system as the calculation reference point, combined with the ship's main dimensions and the current six-degree-of-freedom motion parameters. The wave load model is based on potential flow theory combined with the three-dimensional hull profile for data simulation. An interpolation lookup table for wave pressure coefficient with respect to relative wave direction and wave period is established. The relative wave direction is the difference between the wave direction and the bow angle at the current moment. For the inland waterway conditions at the current moment, the wave pressure coefficient of the hull surface corresponding to the wave direction is looked up. Based on linear wave theory, the instantaneous wave pressure amplitude at each point on the hull surface is calculated according to the significant wave height and the wave pressure coefficient. The sign of the instantaneous wave pressure amplitude is determined according to the wave phase. The instantaneous wave pressure distribution on the hull surface is then obtained by integrating the data. By retrieving structural mechanics parameters, the instantaneous wave pressure distribution on the hull surface is integrated along the ship's length to obtain the vertical wave shear force distribution along the ship's length. The vertical wave shear force is then integrated again along the ship's length to obtain the wave bending moment distribution along the ship's length. These are then combined to obtain the dynamic bending moment distribution vector.

6. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 5, characterized in that: The deformation trend data is obtained in the following ways: Based on the bending theory of variable cross-section elastic beams, by substituting the wave bending moment and structural stiffness matrix, including the structural mechanical parameters, at the current moment, the static bending response curve of the hull under the current wave load is obtained. The static bending response curve represents the vertical deflection value distributed along the length of the ship. The maximum vertical deflection value and the corresponding longitudinal position of the hull bending upward and downward are extracted from the static bending response curve to obtain the mid-camber amplitude and mid-sag amplitude. The deformation trend data of the hull are then integrated.

7. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 2, characterized in that: The dynamic offset compensation method is as follows: Using the current moment as a reference, the dynamic bending moment distribution vector, deformation trend data, and real-time sensing data are obtained as input data and synchronized in time. The deflection curve data at the current moment is extracted from the real-time sensing data, and the static bending response curve predicted based on the dynamic bending moment distribution vector at the same moment is extracted from the deformation trend data. A complementary filtering strategy is adopted to weight and fuse the measured deflection on the deflection curve data and the vertical deflection value on the static bending response curve according to the preset fusion weight, so as to obtain the dynamic deflection curve composed of the fused deflection value. If the fused deflection value of the dynamic deflection curve exceeds the preset large deformation threshold, a preset nonlinear correction coefficient is introduced to multiply the fused deflection value of the large deformation area of ​​the hull. The corrected dynamic deflection curve is discretized to the longitudinal position corresponding to each ship feature point, and the vertical dynamic offset of each ship feature point in the hull coordinate system is obtained. This offset is then superimposed with the theoretical three-dimensional coordinates of the ship feature points to obtain the corrected instantaneous coordinates of the ship feature points in the hull coordinate system, thus completing the dynamic offset compensation.

8. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 7, characterized in that: The method for generating the global coordinate set of compensated feature points is as follows: The ship feature points with the closest positioning state to the origin of the ship's coordinate system are extracted from the BeiDou positioning data and used as fixed reference points for the ship. The absolute three-dimensional coordinates of the ship's fixed reference points in the geocentric coordinate system are extracted. A real-time rotation matrix from the ship's coordinate system to the geocentric coordinate system is constructed based on attitude and motion data. For each ship feature point, the data is processed in combination with the corresponding corrected instantaneous coordinates of the ship's coordinate system to obtain the compensated global coordinates of the ship feature points in the geocentric coordinate system. The compensated global coordinate group of the feature points is then integrated.

9. The method for dynamically generating ship contours based on BeiDou positioning data according to claim 1, characterized in that: The real-time ship profile model is generated as follows: Based on the current extreme attitude state determination result, the corresponding feature point global coordinate group or the compensated feature point global coordinate group is selected as the input coordinate group. Based on the three-dimensional hull lines in the ship's static design parameters, a reference surface model of the hull profile is established. The input coordinate group is transformed to the measured position coordinates with the origin of the hull coordinate system as the reference. The radial basis function interpolation method is used to construct a continuous displacement field from the reference surface model to the measured position coordinates of each ship feature point. The measured position coordinates of the entire hull surface are discretized into point cloud data to generate a real-time ship profile model.

10. A device for dynamically generating ship outlines based on BeiDou positioning data, the device being used to implement the generation method described in any one of claims 1-9, characterized in that, include: Data sensing module: acquires ship static design parameters and deploys a multimodal sensor network to collect real-time sensing data; Extreme attitude determination and coordinate analysis module: Based on the ship's static design parameters and real-time sensing data, determine whether the ship has entered an extreme attitude state. If not, generate a global coordinate set of the ship's feature points. Environmental and Deformation Analysis Module: If entered, it constructs a wave load model, calculates the dynamic bending moment distribution vector, and predicts the deformation trend data of the hull; Offset compensation module: Based on dynamic bending moment distribution vector and deformation trend data, combined with real-time sensing data, dynamic offset compensation is performed to generate a global coordinate group of compensation feature points of the ship. Contour generation module: Generates a real-time ship contour model based on the global coordinate group of feature points or the compensated global coordinate group of feature points.

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