Yaw early warning identification method and system for ship entering and leaving port

Abstract

The invention provides a ship port entering and leaving yaw early warning identification method and system which are applied to the technical field of shipping informatization, ship traffic management and maritime safety monitoring, and the method comprises the steps: obtaining a channel center line and a yaw threshold value, receiving the data of a ship automatic identification system in real time, determining a track direction, determining a reference channel section, and determining a yaw threshold value; the included angle between the track direction and the reference channel section is calculated, and an early warning signal is generated when the included angle is larger than the threshold value. According to the scheme, the hysteresis quality of manual monitoring can be effectively avoided, and the problems that early warning is not timely and the accuracy is low in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the fields of shipping informatization, ship traffic management and maritime safety monitoring, and in particular to a method and system for early warning and identification of ship deviation when entering or leaving port. Background Technology

[0002] With increasingly busy maritime transport, the issue of ship navigation safety has become increasingly prominent. When entering or leaving ports or navigating narrow waters, ships are easily affected by various factors and may deviate from their planned routes, leading to safety accidents. Therefore, effective early warning of ship deviations is of great significance.

[0003] Currently, ship navigation monitoring mainly relies on manual monitoring and automatic monitoring systems. Manual monitoring depends on VHF radio and radar, with human observation and judgment, making it susceptible to subjective factors and prone to delays. Automatic monitoring systems attempt to introduce automated processing, but still have shortcomings. For example, some systems determine deviations by comparing the ship's current trajectory with historical standard tracks, but this requires a large amount of historical data, involves complex modeling processes, and is computationally intensive, making it difficult to meet real-time requirements. Furthermore, the data from Automatic Identification Systems (AIS) contains noise, easily leading to misjudgments, and lacks consideration for the differentiated safety requirements of different navigation segments.

[0004] Current technologies struggle to balance computational efficiency, early warning accuracy, and environmental adaptability. Therefore, there is an urgent need for a fast, accurate, and adaptive ship yaw warning technology to improve navigation safety.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a method and system for early warning and identification of ship deviation when entering and leaving port, which aims to solve the technical problems of delayed early warning, complex algorithms and poor adaptability in the prior art. By performing real-time processing and simplified geometric calculations on the data of the Automatic Identification System (AIS), the method and system can quickly and accurately identify and warn of the risk of ship deviation in port channels.

[0007] This invention provides a method for early warning and identification of ship deviation when entering or leaving port, comprising: Acquire channel centerline data and yaw angle thresholds, which consist of multiple consecutive straight line segments; It receives real-time data from the target vessel, including its current physical location coordinates, and determines the target vessel's course based on the data. In a series of consecutive straight segments, determine the reference channel segment corresponding to the current physical position coordinates of the target vessel; Calculate the angle between the track direction and the reference channel segment; When the included angle is greater than the yaw angle threshold, an electronic warning signal is generated.

[0008] In some alternative embodiments, the step of determining the baseline channel segment includes: Calculate the vertical projection point of the target vessel's current physical position coordinates onto the channel centerline represented by the channel centerline data, and determine the straight line segment where the vertical projection point is located as the reference channel segment.

[0009] In some alternative embodiments, the step of determining the baseline channel segment includes: Calculate the distance from the current physical position coordinates of the target vessel to each of the multiple consecutive straight line segments, and determine the straight line segment with the smallest distance as the reference waterway segment.

[0010] In some alternative embodiments, the step of determining the course includes: Obtain the current physical position coordinates and the physical position coordinates of the target vessel at the previous moment, and determine the course based on the current physical position coordinates and the physical position coordinates of the previous moment.

[0011] In some optional embodiments, the method further includes the following step before determining the course direction: Receive an automatic identification system data sequence containing multiple consecutive physical location coordinates of the target vessel within a time window; The data sequence of the automatic identification system is smoothed and filtered to obtain optimized coordinates of multiple physical locations. The flight path is determined based on two coordinates from multiple optimized physical location coordinates.

[0012] In some alternative embodiments, smoothing filtering is performed using a Kalman filter algorithm or a weighted moving average algorithm.

[0013] In some optional embodiments, each straight line segment in the channel centerline data is associated with an independent yaw angle threshold. The method also includes: after calculating the included angle, extracting an independent yaw angle threshold associated with the reference channel segment; The step of comparing the included angle with the yaw angle threshold is specifically: comparing the included angle with the extracted independent yaw angle threshold.

[0014] In some alternative embodiments, the independent yaw angle threshold is preset based on at least one of the physical characteristics of the channel width, channel depth, or channel curvature corresponding to the straight segment to which it is associated.

[0015] In some optional embodiments, the step of calculating the included angle includes: Calculate the course direction and the azimuth of the reference channel segment relative to true north, respectively. The included angle is determined based on the difference between the azimuth angles.

[0016] In some optional embodiments, when the difference between azimuth angles is greater than 180 degrees, the difference between 360 degrees and the difference is taken as the included angle.

[0017] In some optional embodiments, the method further includes: Obtain the preset channel boundary data; Before generating an electronic warning signal, it is determined whether the current physical position coordinates of the target vessel are within the channel boundary defined by the channel boundary data.

[0018] In some optional embodiments, the method further includes: Based on the target vessel's current physical position coordinates and its physical position coordinates at the previous moment, determine the target vessel's navigation status; The navigation status includes one of the following: entering the channel, navigating within the channel, or leaving the channel.

[0019] In some optional embodiments, the method further includes: When the navigation status is within the channel and the target vessel's yaw status changes from not yawed to yawed, a yaw start event is generated. When the navigation status is within the channel and the target vessel's yaw status changes from yaw to no yaw, a yaw termination event is generated.

[0020] In some alternative embodiments, the generated electronic warning signal is configured as a control signal to drive visual or auditory alarm devices.

[0021] In some alternative embodiments, the visual alarm device is an electronic chart display terminal, and the control signal is used to drive the electronic chart display terminal to highlight or flash the icon of the target vessel.

[0022] This invention provides a ship yaw warning and identification system for entering and leaving ports, comprising: The data acquisition module is configured to acquire channel centerline data consisting of multiple consecutive straight line segments and yaw angle thresholds, and to receive automatic identification system data containing the current physical position coordinates of the target vessel in real time. The track determination module, connected to the data acquisition module, is configured to determine the track and direction of the target vessel based on data from the automatic identification system. The yaw calculation module, connected to the data acquisition module and the track determination module, is configured to: determine the reference channel segment corresponding to the current physical position coordinates of the target vessel in multiple consecutive straight segments; and calculate the angle between the track direction and the reference channel segment. The warning generation module, connected to the yaw calculation module, is configured to compare the included angle with a yaw angle threshold and generate an electronic warning signal when the included angle is greater than the yaw angle threshold.

[0023] In some optional embodiments, the track determination module is also configured to: Receive an automatic identification system data sequence containing multiple consecutive physical location coordinates of the target vessel within a time window; The data sequence of the automatic identification system is then smoothed and filtered to obtain optimized coordinates of multiple physical locations. The flight path is determined based on two coordinates from multiple optimized physical location coordinates.

[0024] In some optional embodiments, in the channel centerline data acquired by the data acquisition module, each straight line segment is associated with an independent yaw angle threshold preset according to the channel physical characteristics of that straight line segment; The warning generation module is also configured to: extract independent yaw angle thresholds associated with the baseline channel segment, and compare the included angle with the extracted independent yaw angle thresholds.

[0025] In some optional embodiments, the yaw calculation module is specifically configured to determine the reference channel segment in the following manner: Calculate the vertical projection point of the target vessel's current physical position coordinates onto the channel centerline represented by the channel centerline data, and determine the straight line segment where the vertical projection point is located as the reference channel segment.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention.

[0027] The ship yaw warning and identification method and system for entering and leaving port of the present invention has the following beneficial effects: The early warning identification method of this invention replaces the complex and time-consuming trajectory fitting and comparison with simple geometric vector calculations, reducing the computational load and meeting the real-time requirements of early warning under busy port traffic. By introducing smoothing filtering processing on the raw AIS data, it effectively suppresses misjudgments and omissions caused by physical signal noise, ensuring the stability of the trajectory judgment and improving the overall reliability of the early warning. The model that binds "segmented centerline and independent dynamic threshold" enables the early warning strategy to adapt to the different safety requirements of various sections of the waterway, significantly improving the accuracy and effectiveness of the early warning. It does not rely on massive amounts of historical data, reducing the deployment and usage costs of the system. Attached Figure Description

[0028] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0029] Figure 1 This is a flowchart of a method for early warning and identification of ship deviation when entering or leaving port, as disclosed in one embodiment of the present invention; Figure 2 This is a flowchart of a method for early warning and identification of ship yaw during port entry and exit according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the relationship between a ship's navigation trajectory and a waterway according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the yaw judgment logic of one embodiment of the present invention; Figure 5 This is a schematic diagram of the geometric relationship for calculating the deviation angle according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating two cases of calculating the deviation angle based on the azimuth angle according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a ship entry / exit yaw warning and identification system according to an embodiment of the present invention. Detailed Implementation

[0030] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the invention will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0031] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0032] The flowchart shown in the attached diagram is merely an illustrative example and does not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined. Therefore, the actual execution order may change depending on the specific circumstances.

[0033] When a ship navigates on water, its motion is influenced by various factors, including its own power, water currents, wind force, and human control. Automatic Identification Systems (AIS) can provide real-time position information, but raw AIS data is susceptible to noise interference and may deviate from the ship's true position. Port channels typically have complex geometries, and the risk of ship veergence is closely related to channel characteristics. To achieve accurate veergence warnings, it is necessary to combine principles of ship kinematics and geometry. Specifically, by analyzing the trend of a ship's position changes at consecutive points in time, its navigation direction can be estimated. Simultaneously, approximating complex curved channels as a series of straight segments simplifies the mathematical description of the channel environment. By calculating the angle between the ship's navigation direction and the channel's reference direction in real time and comparing it with a preset veergence threshold, it is possible to determine whether the ship has deviated from its safe course. This threshold is adjusted according to channel characteristics, enabling the warning system to adapt to the safety requirements of different sections of the waterway, effectively reducing false alarm rates and improving the accuracy and reliability of warnings.

[0034] Please see Figure 1 This embodiment provides a basic implementation of a method for early warning and identification of ship yaw during port entry and exit. This method can be executed by computer equipment and specifically includes the following steps: First, the steps of defining the main channel, centerline, and yaw angle are performed. In this step, channel geographic information is pre-configured and stored in the system. Specifically, a channel centerline representing the channel's center path is defined using a series of geographic coordinate points, and this centerline is processed into multiple continuous straight line segments within the system. Simultaneously, a global, fixed yaw angle threshold, such as 30 degrees, is set for the entire early warning system; this threshold serves as a unified benchmark for all subsequent yaw judgments.

[0035] Next, the system performs the step of collecting real-time AIS data of the vessel. In this step, the system receives AIS data broadcast by the target vessel in real time and continuously through the communication interface, and parses the current physical position coordinates and the physical position coordinates of the previous moment from it.

[0036] Next, the system calculates the angle between the track direction and the centerline. In this step, the system first determines a track direction representing the ship's current instantaneous navigation direction based on the acquired current physical position coordinates and the physical position coordinates from the previous moment. Then, based on the ship's current physical position coordinates, the system selects the closest straight line segment from a set of pre-stored channel centerline straight lines as the reference channel segment. Finally, the system calculates the angle between the track direction and the reference channel segment.

[0037] Next, the system compares the included angle with the yaw angle to determine yaw. In this step, the system compares the included angle calculated in the previous step with the global, fixed yaw angle threshold set in the first step. If the calculated included angle is greater than the yaw angle threshold, the system determines that the ship has yawed.

[0038] Finally, upon determining that the vessel has yawed, the procedure for notifying relevant personnel is executed. In this step, the system generates an electronic warning signal and sends it to the monitoring terminal at the VTS center via the network or a dedicated interface, alerting the on-duty personnel through sound, light, or interface highlighting.

[0039] It should be understood that this embodiment discloses the basic technical solution of the present invention. In other preferred embodiments, the steps of this embodiment can be further optimized and enhanced. For example, a step of smoothing and filtering the data can be added after acquiring AIS data to improve the accuracy of the flight path; alternatively, a fixed yaw angle threshold can be replaced with a variable, independent yaw angle threshold bound to each straight segment of the channel centerline to improve the adaptability and accuracy of the warning. These optimizations and enhancements all fall within the scope of protection claimed by the present invention.

[0040] like Figure 2 As shown in the figure, this invention provides a method for early warning and identification of ship yaw during port entry and exit, which includes the following steps: Step S100: Obtain channel centerline data and yaw angle threshold. In one embodiment, the channel centerline data consists of multiple consecutive straight line segments, each representing a portion of the channel. These straight line segments can be pre-stored in a database and defined and updated by port management personnel or relevant technical personnel using Geographic Information System (GIS) software. The channel centerline data includes the geographic coordinates of the start and end points of each straight line segment. The yaw angle threshold represents the maximum angle by which a vessel is allowed to deviate from the channel centerline; exceeding this angle is considered a yaw risk. This threshold can be a pre-set fixed value or dynamically adjusted according to the specific conditions of the channel. In some implementations, configuration files or database tables can be used to store the channel centerline data and yaw angle threshold.

[0041] Step S200: Receive the Automatic Identification System (AIS) data of the target vessel in real time and determine the target vessel's trajectory based on the AIS data. The AIS data contains dynamic information about the vessel, such as position coordinates, heading, and speed. The system receives this data through the AIS receiving device and extracts the vessel's current physical position coordinates. The trajectory represents the vessel's current direction of motion and can be determined by analyzing AIS data over a period of time. In one example, the trajectory can be obtained by calculating the vector between two consecutive positions of the vessel. In other optional implementations, algorithms such as Kalman filtering can be used to process the AIS data to improve the accuracy of the trajectory.

[0042] Step S300: Determine the reference channel segment corresponding to the current physical position coordinates of the target vessel. Since the channel centerline is divided into multiple consecutive straight segments, it is necessary to determine the straight segment in which the vessel is currently located as the reference for subsequent calculations. In one embodiment, the reference channel segment can be determined by judging which straight segment the vessel's position coordinates fall within. In other optional implementations, spatial indexing techniques, such as R-trees or quadtrees, can be used to accelerate the search process.

[0043] Step S400: Calculate the angle between the track direction and the reference channel segment. This angle represents the degree of deviation between the ship's sailing direction and the direction of the channel centerline. In one embodiment, the angle can be calculated by calculating the dot product or cross product between the track direction and the reference channel segment vector. In other embodiments, trigonometric function formulas, such as the law of cosines or the law of sines, can be used to calculate the angle.

[0044] Step S500: When the included angle is greater than the yaw angle threshold, an electronic warning signal is generated. This warning signal is used to alert relevant personnel that the vessel is at risk of yaw. In one embodiment, the warning signal may include the vessel's identification information, current position, yaw angle, etc., and can be sent to a monitoring center or other relevant systems via a network. In some optional implementations, different warning levels can be set, and different response measures can be taken according to the degree of yaw. The electronic warning signal can be converted into an auditory or visual alarm, such as highlighting the vessel on the display of a VTS (Vessel Traffic Management) system.

[0045] Steps S100 to S500 work together to achieve real-time early warning of ship yaw risk. First, step S100 provides basic channel geometry information and safety thresholds, which are the basis for yaw judgment. Step S200 acquires the ship's dynamic position information in real time and calculates its course, providing a basis for judging the yaw direction. Step S300 correlates the ship's position information with channel information to determine the benchmark for yaw judgment. Step S400 calculates the angle between the course and the benchmark channel segment, quantifying the degree of yaw. Finally, step S500 compares the degree of yaw with the safety threshold and issues an early warning when the threshold is exceeded, thus achieving effective identification and early warning of yaw risk. This collaborative approach, by simplifying the channel by segmentation and comparing the ship's course with the channel benchmark in real time, avoids complex historical trajectory comparisons and solves the technical problems of high computational load and poor real-time performance in existing technologies.

[0046] Through the above-described scheme, this embodiment can achieve rapid and accurate early warning of vessel yaw risk. Compared with the prior art, the advantages of this embodiment are: it simplifies the calculation model and improves the real-time performance of the early warning; by directly comparing the track direction with the channel direction, it avoids complex trajectory matching and reduces computational complexity; and by setting a yaw angle threshold, it can effectively identify vessels with yaw risk, thereby ensuring the safe and smooth flow of the waterway.

[0047] Please refer to the following: Figure 3 . Figure 3 A typical application scenario according to an embodiment of the present invention is illustrated. In the accompanying figure, the area enclosed by the solid line boundary represents the waterway, and the dashed line represents the pre-defined centerline of the waterway. The series of black dots from P0 to P7 shown in the figure represent a series of ship position coordinates obtained in real time after being received and processed in step S200. The directed arrows connecting these position points visually represent the track direction determined in step S200, representing the instantaneous navigation direction of the ship.

[0048] In this scenario example, the vessel is initially located at position P0 outside the channel, and then enters the channel at position P1. During the journey from P1 to P5, the vessel's course (e.g., the course determined by positions P2 and P3) is substantially parallel to the centerline corresponding to that segment. During this phase, the deviation angle calculated by the system in step S400 will remain less than the yaw angle threshold obtained in step S100; therefore, no warning signal will be generated in step S500.

[0049] After the ship passes position P5, its course begins to change significantly. The course determined by positions P5 and P6 forms a clear angle with the centerline. At this point, in step S300, the system associates the ship's current position with its adjacent reference channel segment, and in step S400, it calculates this increased angle in real time. In step S500, the system compares this angle with the yaw angle threshold corresponding to the reference channel segment. If the angle exceeds the threshold, the system will generate an electronic warning signal for the first time. Subsequently, the course determined by positions P6 and P7 further exacerbates the deviation, and the system will continue to determine that the ship is in a yaw state.

[0050] pass Figure 3 As can be clearly seen from the scenario shown, the method of the present invention can effectively identify and warn of a ship in the initial stage when it just begins to show a tendency to yaw (such as the stage from P5 to P6), thereby buying valuable time for relevant personnel to take corrective measures, demonstrating the technical effect of the present invention.

[0051] In one specific implementation, the step of determining the reference channel segment includes: first, the system obtains the optimized current physical position coordinates of the vessel from the data acquisition module. ,in, This represents the optimized current physical position coordinates of the vessel. The latitude component of the current physical location coordinates. This refers to the longitude component of the current physical location coordinates. Simultaneously, the system acquires a series of straight line segments. The data constitutes the centerline of the waterway. Specifically, to uniquely determine the reference waterway segment, the system processes each straight segment... Execution judgment: Calculation In containing The projection point on the infinite straight line is determined, and it is determined whether the projection point falls on the straight line segment. Between the two endpoints. If there exists a unique straight line segment. If the condition that the projection point falls between its endpoints is satisfied, then the straight line segment... The selected section is designated as the baseline navigation channel. If the above conditions are not met on all straight segments (i.e., all projected points fall on the extension of the corresponding straight segment), the system will perform further calculations. To each straight segment The shortest distance is determined, and the straight segment with the smallest shortest distance is identified as the reference waterway segment.

[0052] Through the above scheme, this embodiment can accurately associate the ship's position with the most relevant segment on the centerline of the waterway, providing an accurate reference benchmark for subsequent yaw calculations.

[0053] In one specific implementation, the step of determining the reference channel segment may further include: the system acquiring the optimized current physical position coordinates of the vessel. ,in, This represents the optimized current physical position coordinates of the vessel. The latitude component of the current physical location coordinates. This refers to the longitude component of the current physical location coordinates. Specifically, the system iterates through the pre-stored coordinates... A continuous straight line segment The system generates the centerline data of the waterway. Then, the system calculates the position coordinates respectively. To each straight segment shortest distance Calculate the shortest distance. The process includes: calculation To include the straight line segment The projection point on the infinite straight line; if the projection point is located on the straight line segment Between the two endpoints, then equal The perpendicular distance to the infinite straight line; if the projection point is located on the straight line segment. On the extension line, then equal to the straight segment The distance between the two endpoints is the closer one. Then, for all calculated distances... In the middle, the system finds the minimum value. The minimum value Corresponding line segment This segment is then identified as the baseline waterway segment. In some other alternative implementations, the shortest distance is calculated. Other equivalent geometric algorithms can also be used, such as vector methods based on vector dot products and cross products. Furthermore, to improve computational efficiency, nearby channel segments can be initially selected based on the ship's position before performing precise distance calculations, thus avoiding traversing all channel segments.

[0054] Through the above solution, this embodiment can ensure that even if the ship is not on the centerline of the channel, it can accurately find the nearest channel segment as a reference benchmark, thereby improving the accuracy of yaw warning, especially in areas where the channel is curved or bifurcated.

[0055] In one specific implementation, the course is determined as follows: First, the data acquisition module extracts the current physical position coordinates of the target vessel from the AIS message. and the physical location coordinates of the previous moment ,in, Represents the current physical location coordinates. The longitude of the current physical location coordinates. The latitude of the current physical location coordinates; Represents the physical location coordinates at the previous moment. The longitude of the physical location coordinates at the previous moment. This refers to the latitude of the physical location coordinates at the previous moment. Then, the track determination module quantizes the displacement direction between these two coordinate points into a track direction. Specifically, this module calculates the trajectory from the starting point... To the finish line The initial azimuth of the geoid. To ensure accuracy in calculations across different latitudes, the azimuth is preferably calculated using spherical trigonometry based on the WGS84 ellipsoid model. The calculated azimuth is then normalized to... Within this range, the value is determined as the track direction representing the instantaneous navigation direction of the target vessel. In some other alternative implementations, to simplify calculations, the Mercator projection can also be used to represent the geographic coordinates. and Convert to planar coordinates, and then calculate the course direction based on the planar coordinates in the planar coordinate system.

[0056] Through the above scheme, this embodiment can determine the ship's course in a simple and direct way, providing basic data for subsequent yaw angle calculation and early warning judgment.

[0057] In one specific implementation, prior to the course determination step, the system receives a raw data stream from an AIS receiver. First, the data acquisition module stores multiple consecutive AIS position reports within a certain time span (e.g., 30 seconds) in a time-series queue. Specifically, each position report includes a timestamp and the ship's latitude and longitude coordinates. Then, a data smoothing algorithm is applied to the data in the queue to reduce the impact of noise. In one implementation, the data smoothing algorithm utilizes statistical characteristics in the time domain to perform a weighted average of the position coordinates in the queue, where the closer the position coordinate is to the current time, the higher its weight. Next, based on the smoothed position coordinate sequence, the optimized current position and the optimized previous position are calculated. Finally, these two optimized position coordinates are passed to the subsequent course determination step to calculate the ship's instantaneous course. In other optional implementations, different data processing strategies can be employed, such as median filtering or Savitzky-Golay filtering, to improve the quality of the position data.

[0058] Through the above solution, this embodiment can effectively suppress random noise in the automatic identification system data, reduce the deviation in track direction calculation caused by positioning error, and thus improve the reliability and accuracy of yaw warning.

[0059] In one specific implementation, a Kalman filter algorithm can be used to smooth and filter the data sequence of the Automatic Identification System (AIS). Specifically, the Kalman filter is configured to recursively estimate the ship's position and velocity state. The system pre-defines the process noise covariance matrix and the measurement noise covariance matrix to describe the uncertainties in the system state transition and measurement process. For each newly received AIS position point, the Kalman filter first predicts the current state based on the state estimate of the previous time step; it then calculates the Kalman gain based on the actual received AIS position point; finally, it uses the Kalman gain to correct the predicted state, obtaining the optimal state estimate for the current time step, i.e., the position point after smoothing and filtering.

[0060] Alternatively, in another implementation, the smoothing filtering process can also employ a weighted moving average algorithm. Specifically, the system assigns a weight to each physical location coordinate within the time window, where the weight of a physical location coordinate is greater the closer it is to the current time. For example, for the physical location coordinates contained within the time window... A sequence of physical location coordinates arranged in chronological order ,in For the latest physical location coordinates, then assign to the first physical location coordinates weight It can be determined using the following linear weighting formula:

[0061] in, Representative assigned to the first The weight of each physical location coordinate. and From 1 to Integer index, This represents the total number of physical location coordinates within the time window. Then, by calculating the weighted average of all physical location coordinates, an optimized location coordinate system is obtained. This coordinate can be used as the optimized current physical position coordinate of the target ship, and its calculation formula is as follows:

[0062] in, This represents the optimized position coordinates. Represents the first in the sequence The physical location coordinates.

[0063] Through the above scheme, this embodiment can effectively filter out noise and jump points in the data of the automatic identification system by using Kalman filtering or weighted moving average algorithm, so as to obtain more accurate and stable ship position information, thereby improving the reliability and accuracy of yaw warning.

[0064] In one specific implementation, during the initialization phase of the waterway model, when the data acquisition module reads the waterway centerline data from the geographic information database, it does not simply read the coordinates of the straight line segments, but rather reads a data structure containing the coordinates of the straight line segments and their associated yaw angle thresholds. This data structure can be a hash table or a key-value database, where a unique identifier for each straight line segment (e.g., a combination of the coordinates of the start and end points of the segment) serves as the key, and the corresponding yaw angle threshold serves as the value.

[0065] During the yaw detection and event generation phase, after determining the baseline channel segment, the warning generation module does not use a globally unique yaw angle threshold. Instead, it queries the data acquisition module, using the identifier of the baseline channel segment as the key, to extract an independent yaw angle threshold associated with that channel segment from the data structure. The warning generation module then compares the calculated deviation angle with the extracted independent yaw angle threshold corresponding to the currently associated baseline channel segment to determine whether to trigger an alarm.

[0066] To illustrate this judgment process more clearly, please refer to [link / reference]. Figure 4 . Figure 4A specific example of the yaw judgment logic of the present invention is shown, where the dashed line represents the direction of the reference channel segment. In this example, it is assumed that the system presets an independent yaw angle threshold of 45 degrees for the reference channel segment based on its physical characteristics (e.g., the segment is relatively wide). When the ship's track direction is P1 to P2, the calculated deviation angle is 20 degrees, which is less than the threshold of 45 degrees, so the system determines that there is no yaw. When the ship's track direction changes to P1 to P3, the calculated deviation angle is 60 degrees, which is greater than the threshold of 45 degrees, so the system determines that a yaw has occurred and generates an electronic warning signal. This example shows that the present invention can use different yaw judgment criteria for different sections of the channel, thereby improving the flexibility and accuracy of the warning system and reducing the false alarm rate.

[0067] In other alternative implementations, the channel centerline data and its associated yaw angle thresholds can also be stored in a distributed caching system (such as Redis or Memcached) to improve data read speed and system responsiveness. Alternatively, a relational database can be used, establishing a channel straight line segment table and a yaw threshold table, and linking the straight line segments and yaw thresholds through foreign key associations.

[0068] In one specific implementation, when initializing a waterway model, technicians not only need to divide the waterway into straight segments, but also need to set a yaw angle threshold for each straight segment. Specifically, for the waterway width, the yaw angle threshold associated with straight segments of narrow waterways (e.g., less than 50 meters wide) is set to a smaller value (e.g., 10 to 20 degrees) to improve sensitivity to yaw; while the yaw angle threshold associated with straight segments of wide waterways (e.g., more than 200 meters wide) is set to a larger value (e.g., 30 to 45 degrees) to allow for greater navigation freedom.

[0069] For straight sections of waterways with shallow water depth (e.g., less than 10 meters), the yaw angle threshold is set to a smaller value (e.g., 15 to 25 degrees) to provide early warning of potential grounding risks due to the higher risk of ships running aground. For straight sections of waterways with deeper water depth (e.g., greater than 30 meters), the yaw angle threshold can be appropriately increased.

[0070] For straight sections corresponding to curves with large channel curvature, the larger the curvature (e.g., a radius of curvature of less than 500 meters), the smaller the yaw angle threshold should be (e.g., 5 to 15 degrees) to ensure safe turning of ships within the curve; while for almost straight sections of the channel, where the curvature is close to zero, the yaw angle threshold can be set to a relatively large value.

[0071] In other alternative implementations, the yaw angle threshold can be determined by comprehensively considering multiple factors such as channel width, water depth, and curvature. For example, a weighted average method can be used, assigning different weights to each factor, and calculating the final yaw angle threshold based on these weights.

[0072] Through the above solution, this embodiment enables the yaw warning system to be more intelligent, and can adaptively adjust according to the actual conditions of different sections of the waterway, thereby improving the accuracy and effectiveness of the warning and reducing the false alarm rate.

[0073] In one specific implementation, the step of calculating the included angle includes: The calculation module determines the azimuth angles of the track direction (representing the ship's navigation direction) and the reference channel segment vector (representing the reference channel direction). The azimuth angle is defined here as the angle formed by rotating the vector clockwise relative to true north, ranging from 0 to 360 degrees. Methods for determining the azimuth angle include, but are not limited to, using spatial analysis functions provided by Geographic Information System (GIS) software, or calculating the arctangent value from the coordinate components of the vector. Specifically, for the track direction, it can be calculated using the latitude and longitude coordinates of the ship's current and previous positions; for the reference channel segment vector, it can be calculated using the latitude and longitude coordinates of the two endpoints constituting the straight segment.

[0074] The calculation module calculates the angle between the flight path and the reference channel segment based on the determined azimuth. The angle is calculated by subtracting the azimuth angles.

[0075] For a clearer explanation of the geometric relationships involved in this calculation, please refer to [link / reference]. Figure 5 In this attached diagram, the dashed line connecting hollow dots represents the reference channel segment, and its direction is the direction of the reference channel segment vector. Solid black dots represent two consecutive coordinates of the vessel's position, and the solid arrow connecting these two dots represents the course direction. Figure 5 As shown, the task of this step is to calculate the directional deviation between the trajectory direction (solid arrow) and the reference channel segment vector (dashed segment), which is the included angle.

[0076] In some other alternative implementations, the angle between the track direction and the reference channel segment vector can be calculated directly using the inner product formula of vectors, without first calculating their respective azimuths.

[0077] Through the above scheme, this embodiment can accurately calculate the angle between the ship's course and the reference channel segment, providing accurate angle data for subsequent yaw judgment.

[0078] In one specific implementation, the system first acquires the trajectory directions respectively. Azimuth relative to true north and the benchmark navigation channel section Direction vector Azimuth relative to true north Then, the system calculates the absolute difference between the two azimuth angles. .

[0079] To ensure that the calculated deviation angle is always the minimum angle between the two directions (i.e., less than or equal to 180°), please refer to the calculation rules used in this embodiment. Figure 6 . Figure 6 Two typical calculation scenarios are shown, where NS represents the due north-south direction, vector OA represents the track direction, and vector OB represents the direction of the reference channel segment. For example... Figure 6 As shown, when the difference between two azimuth angles is greater than 180° (as shown in the right sub-figure), specific calculations are required to obtain the minimum included angle.

[0080] Specifically, the system further determines: if the difference If the angle is greater than 180°, then the final deviation angle is... The calculation formula is: Otherwise, the deviation angle equal to the difference .

[0081] For example, suppose It's 350°. It's 10°. Specifically, the calculated difference... Due to the difference (340°) is greater than 180°, this situation corresponds to Figure 5 The logic shown in the right sub-diagram, therefore, leads to the final deviation angle. Next, the system will adjust the deviation angle. (20°) and the aforementioned reference channel section Corresponding yaw angle threshold The comparison is performed to determine whether an alert has been triggered.

[0082] In some alternative implementations, the same function can be achieved by consulting a pre-established mapping table of azimuth differences and final deviation angles. Through the above approach, this embodiment ensures that the calculated deviation angle is always the minimum angle between the flight path and the reference channel segment, thereby avoiding misjudgments caused by azimuth calculations and improving the accuracy of yaw warnings.

[0083] In one specific implementation, the system first acquires preset channel boundary data. This channel boundary data consists of a series of ordered geographic coordinate points that define the channel's boundary extent. This data can be stored in a Geographic Information System (GIS) database or as a file in a common geographic data format such as Shapefile or GeoJSON. The data acquisition module reads this data from a specified storage location and constructs a polygonal data structure in memory for subsequent location determination.

[0084] Specifically, before generating an electronic warning signal, the system needs to determine whether the target vessel's current physical position coordinates are within the channel boundary defined by the channel boundary data. One implementation method is to use a "point inside polygon" algorithm to determine whether the vessel's position is within the channel boundary. Commonly used algorithms include the ray casting algorithm and the winding number algorithm. The ray casting algorithm emits a ray in any direction from the measured point (vessel position) and counts the number of intersections between the ray and the polygon boundary. If the number of intersections is odd, the point is inside the polygon; if the number of intersections is even, the point is outside the polygon. The winding number algorithm calculates the number of times the measured point wraps around the polygon boundary. If the number of wraps is non-zero, the point is inside the polygon; if the number of wraps is zero, the point is outside the polygon. The system can choose one of these algorithms to determine the position.

[0085] In some alternative implementations, the channel boundary is not composed of precise polygons, but rather represented by buffer zones. For example, the channel centerline is buffered to both sides by a certain distance, forming a strip-shaped area. In this case, determining whether a vessel is within the channel boundary can be achieved by calculating the distance from the vessel's position to the channel centerline and comparing it with the width of the buffer zone.

[0086] Through the above scheme, this embodiment can avoid false alarms when the ship is outside the channel. The warning signal will only be generated when the ship is in the channel and meets the yaw conditions, thereby improving the effectiveness and reliability of the warning.

[0087] In one specific implementation, the system further determines the navigation status of the target vessel based on its current physical position coordinates and its physical position coordinates at the previous moment. First, the system maintains a state variable to record the target vessel's current navigation status. This state variable's values ​​include "entering the channel," "navigating within the channel," and "leaving the channel." Specifically, the system calculates the target vessel's average speed and rate of change of course over a period of time. If the average speed is greater than a preset minimum speed threshold and the rate of change of course is less than a preset maximum rate of change threshold, the vessel is considered to be in a normal navigation state. Then, the system determines whether the target vessel's current physical position coordinates are within a preset channel boundary. If the vessel is currently outside the channel boundary but was inside the channel boundary at the previous moment, the navigation status is updated to "leaving the channel." If the vessel is currently inside the channel boundary but was outside the channel boundary at the previous moment, the navigation status is updated to "entering the channel." If the vessel remains within the channel boundary, the navigation status is updated to "navigating within the channel." In other alternative implementations, the navigation status can be determined by combining other AIS information such as the ship's draft and type, or by using other types of state machine models.

[0088] Through the above solution, this embodiment can more accurately identify the navigation status of ships, thereby avoiding unnecessary warnings when ships enter or leave the waterway, and improving the accuracy and effectiveness of the warnings.

[0089] In one specific implementation, the system first needs to maintain a state machine to record the target vessel's navigation and yaw states. Navigation states include entering the channel, navigating within the channel, and leaving the channel. Yaw states include yawed and not yawed.

[0090] Specifically, after the data acquisition module receives new data from the automatic identification system, the track determination module outputs the current physical position coordinates of the target vessel. The system first determines whether these coordinates are within the channel boundary defined by preset channel boundary data. If the vessel is currently outside the channel boundary but was inside it at the previous moment, the state machine updates the navigation state to "leaving the channel". If the vessel is currently inside the channel boundary but was outside it at the previous moment, the state machine updates the navigation state to "entering the channel". If the vessel remains within the channel boundary, the navigation state is "navigating within the channel".

[0091] The yaw calculation module calculates the deviation angle. The system compares this deviation angle with the corresponding independent yaw angle threshold. If the deviation angle is greater than the threshold, and the previous yaw state was "not yawed," the state machine updates the yaw state to "yawed" and generates a "start yaw" event. If the deviation angle is less than or equal to the threshold, and the previous yaw state was "yawed," the state machine updates the yaw state to "not yawed" and generates a "end yaw" event.

[0092] The warning generation module generates corresponding electronic warning signals based on the event type generated by the state machine. For example, when a "starting to veer off course" event is generated, the warning generation module creates an electronic warning signal containing information such as the vessel's MMSI, timestamp, current position, current heading, reference segment heading, and deviation angle, and sends it to the VTS monitoring terminal to trigger an alarm. "Entering the channel" or "leaving the channel" events may not trigger an alarm and are only used for internal system state management.

[0093] In other alternative implementations, the state machine can be implemented using different data structures, such as enumeration types or integer flags to represent navigation and yaw states. The conditions for determining the state can also be more complex, considering factors such as ship speed and turning rate. Event generation can also be customized according to actual needs; for example, "serious yaw" events and "minor yaw" events can be generated, with different alarm levels set.

[0094] Through the above scheme, this embodiment can more accurately identify the yaw status of ships, avoid false alarms caused by frequent entry and exit from the channel boundary, and generate more targeted early warning information based on changes in the yaw status, thereby improving the effectiveness of the early warning.

[0095] In one specific implementation, the electronic warning signal is configured as a control data structure containing predefined fields indicating the type, level, and control commands of the warning. This control data structure can be encoded using JSON, XML, or a custom binary format for cross-platform and cross-system transmission. Specifically, the data structure includes a "target device type" field, which identifies the target receiving and executing device of the warning signal. For example, the "target device type" field can be set to "visual alarm device" or "auditory alarm device." Depending on the "target device type," the data structure will contain different control commands. When the "target device type" is "visual alarm device," the control commands might include displaying text messages on the device screen, changing the color of a specified area, or playing animations; while when the "target device type" is "auditory alarm device," the control commands might include playing sounds at specific frequencies or playing pre-recorded voice alarms. The control commands can also include parameters corresponding to the warning level. For example, in visual alarms, different colors can be used to represent different warning levels (e.g., red represents the highest level of risk), and in auditory alarms, different tones and frequencies can be used to distinguish different warning levels. In other alternative implementations, electronic warning signals can also be encoded directly using the native instruction set of the specific device, for example, directly generating control commands that conform to the protocol of a specific model of audible and visual alarm. Alternatively, warning information can be pushed using a common audio / video streaming protocol (such as RTSP), with visual or auditory alarm devices receiving the warning information by subscribing to a specific streaming address.

[0096] Through the above solution, this embodiment can provide a flexible and scalable electronic early warning signal, which can be parsed and executed by various types of alarm devices, thereby realizing diversified alarm methods and effectively improving the transmission efficiency and coverage of early warning information.

[0097] In one specific implementation, the visual alarm device is configured as an Electronic Chart Display and Information System (ECDIS). First, the electronic warning signal generated by the warning generation module is formatted into a message format conforming to the IEC 61162-1 / 0183 standard, which defines the data exchange protocol between ship navigation devices. Specifically, a statement beginning with "!AIVDM" or a custom statement start character can be used to encapsulate yaw event information, including the ship's MMSI, position, heading, deviation angle, and the threshold for triggering the warning, in the message's data fields. Then, this message is sent to the ECDIS via TCP / IP or serial communication. Next, upon receiving the message, the ECDIS parses it and extracts the yaw event data. Subsequently, the electronic chart display terminal locates the corresponding ship target on the chart interface based on the ship's MMSI and drives the display module to display the ship's icon in a red highlight flashing mode. The flashing frequency is set to 2Hz for example, and the highlight color can be (255, 0, 0) in the RGB color model.

[0098] In some other alternative implementations, the color of the flashing highlight can be adjusted according to the degree of deviation; for example, it can be displayed as yellow when the deviation angle is close to a threshold and as red when the deviation angle is far beyond the threshold. Furthermore, different flashing frequencies can be used to represent different warning levels.

[0099] Through the above solution, this embodiment can utilize standard communication protocols and existing electronic chart display terminals to provide navigation personnel with deviation warning information in an intuitive and eye-catching manner, making it easier for operators to quickly identify risks, take timely corrective measures, and avoid accidents.

[0100] like Figure 7 As shown in the figure, this embodiment of the invention provides a ship yaw warning and identification system for entering and leaving ports. The system includes: a data acquisition module M100, a track determination module M200, a yaw calculation module M300, and a warning generation module M400.

[0101] The data acquisition module M100 is configured to acquire channel centerline data consisting of multiple consecutive straight line segments and yaw angle thresholds. This module has network communication capabilities, enabling it to receive real-time Automatic Identification System (AIS) data from shore-based AIS base stations via wired or wireless means, such as the TCP / IP protocol. The AIS data includes dynamic information about the vessel, such as its MMSI (Maintainer Name System Identifier), timestamp, longitude, and latitude coordinates. The channel centerline data and yaw angle thresholds are stored in a database, such as the relational database PostgreSQL or the spatial database PostGIS. The data acquisition module M100 can read this data from the database using SQL queries. In some alternative implementations, the channel centerline data and yaw angle thresholds can also be stored in an XML or JSON format configuration file, which is then parsed and read by the data acquisition module M100.

[0102] The track determination module M200 is connected to the data acquisition module M100 and is configured to determine the trajectory and heading of a target vessel based on Automatic Identification System (AIS) data. The track determination module M200 receives raw AIS data from the data acquisition module M100 and extracts the vessel's position information from it. The track determination module M200 has built-in data preprocessing logic for preliminary verification of the received AIS data, such as checking the data's completeness and reasonableness. Then, based on the vessel's position information at two consecutive moments, the vessel's trajectory and heading are calculated. In one implementation, the trajectory and heading can be represented as a two-dimensional vector, with the direction pointing towards the vessel's sailing direction.

[0103] The yaw calculation module M300 is connected to the data acquisition module M100 and the track determination module M200. It is configured to determine a reference channel segment corresponding to the current physical position coordinates of the target vessel among multiple consecutive straight line segments, and to calculate the angle between the track direction and the reference channel segment. The yaw calculation module M300 first acquires channel centerline data from the data acquisition module M100. This data consists of multiple straight line segments, each representing a portion of the channel. Then, the yaw calculation module M300 receives the vessel's current position coordinates from the track determination module M200. The yaw calculation module M300 uses a geometric algorithm, such as a point-to-line distance calculation method, to determine the reference channel segment corresponding to the vessel's current position. After determining the reference channel segment, the yaw calculation module M300 calculates the angle between the vessel's track direction and the reference channel segment. In one implementation, this angle can be calculated using a vector angle formula.

[0104] The warning generation module M400 is connected to the yaw calculation module M300 and is configured to compare the included angle with a yaw angle threshold, and generate an electronic warning signal when the included angle is greater than the threshold. The warning generation module M400 receives the included angle value from the yaw calculation module M300 and obtains the yaw angle threshold related to the current channel segment from the data acquisition module M100. The warning generation module M400 compares the two; if the included angle is greater than the threshold, it considers the vessel to have a yaw risk and generates an electronic warning signal. This electronic warning signal may include information such as the vessel identification code, current position, navigation direction, yaw angle, and timestamp. This warning signal can be sent to the Vessel Traffic Service (VTS) or other relevant departments via a network. In some other optional implementations, the electronic warning signal can also be sent to a local alarm device via a serial port.

[0105] The aforementioned modules work together to provide real-time early warning of vessel yaw risk. The data acquisition module M100 acquires raw data and channel information; the track determination module M200 calculates the vessel's track direction; the yaw calculation module M300 determines the baseline channel segment and calculates the deviation angle; and the early warning generation module M400 assesses yaw risk and generates an early warning signal. This modular design allows the system to efficiently and accurately identify vessel yaw behavior and issue timely warnings, thereby reducing the risk of accidents and solving problems such as delayed warnings, complex algorithms, and poor adaptability in existing technologies.

[0106] Through the above scheme, this embodiment can achieve the following beneficial effects: it adopts a modular design, with each module having a clear function, making it easy to maintain and expand; it can receive and process data from the Automatic Identification System (AIS) in real time, and promptly detect yaw risks; it can set different yaw angle thresholds according to the characteristics of the waterway, improving the accuracy of early warnings; and it can generate electronic early warning signals to promptly notify relevant departments and reduce accident risks.

[0107] In one specific implementation, the track determination module M200 includes a data buffer unit, a preprocessing unit, and a smoothing and filtering unit. The data buffer unit receives and stores raw AIS data, including timestamps and position coordinates, from the data acquisition module M100 using a circular queue data structure. The length of the circular queue can be configured, for example, set to 60 elements to correspond to a 30-second time window, assuming the AIS data update frequency is twice per second. The preprocessing unit periodically reads the latest data from the circular queue. These position coordinates form a position coordinate sequence, where For example, a preset positive integer. The smoothing filtering unit applies a Kalman filter algorithm to the position coordinate sequence. Specifically, the Kalman filter algorithm uses a state-space model that includes process noise and measurement noise to estimate the ship's true position and speed; wherein, the process noise describes random disturbances caused by factors such as wind, waves, and ocean currents during the ship's motion, and the measurement noise describes the positioning error of the AIS equipment itself and interference during signal transmission. Based on the statistical characteristics of the process noise and the measurement noise, the smoothing filtering unit recursively estimates the position coordinate sequence and outputs an optimized current position coordinate. ,in This represents the optimized current position coordinates. and These are the latitude and longitude of the optimized current position coordinates, respectively. Simultaneously, the smoothing filter unit also outputs the optimized position coordinates from the previous moment. ,in This represents the optimized position coordinates of the previous moment. and The optimized coordinates of the previous time step are the latitude and longitude, respectively. The optimized current position coordinates and the optimized coordinates of the previous time step are used to calculate the course. In some other optional embodiments, the smoothed filtering unit can use a weighted moving average algorithm instead of the Kalman filter algorithm. The weighted moving average algorithm assigns different weights to each position coordinate within the time window, wherein the position coordinates closer to the current time have a larger weight, and the smoothed position coordinates are obtained by weighted averaging.

[0108] Through the above scheme, this embodiment can effectively filter out random noise and positioning jumps in the data of the automatic identification system, improve the accuracy and stability of the position coordinates, and thus provide a more reliable data basis for subsequent yaw judgment.

[0109] In one specific implementation, the data acquisition module M100 is configured to read channel centerline data from a pre-configured database or file. This data is stored in tabular form, with each row representing a straight segment and containing fields: segment ID, starting point latitude and longitude, ending point latitude and longitude, and an independent yaw angle threshold. For example, the segment ID is "S1", the starting point latitude and longitude is (121.500, 31.200), the ending point latitude and longitude is (121.505, 31.205), and the independent yaw angle threshold is 20 degrees. After receiving the included angle output by the yaw calculation module M300, the warning generation module M400 first extracts the ID of the reference channel segment, and then uses this ID as an index to look up the corresponding yaw angle threshold in the channel centerline data table loaded by the data acquisition module M100. For example, if the reference channel segment ID is "S1", then the yaw angle threshold extracted by the warning generation module M400 is 20 degrees. Subsequently, the warning generation module M400 compares this included angle with the extracted yaw angle threshold to determine whether to generate an electronic warning signal. In some alternative implementations, the channel centerline data can be stored in a NoSQL database, such as MongoDB. The data acquisition module M100 uses the MongoDB query interface, employing the baseline channel segment ID as the query condition, to obtain the corresponding yaw angle threshold. In another implementation, the yaw angle threshold is not directly stored in the channel centerline data table, but rather associated with a separate configuration table. The data acquisition module M100 needs to perform two queries to obtain the final yaw angle threshold. For example, the channel centerline data table only stores the channel segment ID and configuration ID; the corresponding yaw angle threshold is queried from the configuration table using the configuration ID.

[0110] Through the above scheme, this embodiment can configure an independent yaw angle threshold for each straight segment of the waterway, so that the early warning strategy can be adjusted according to the actual situation of different sections of the waterway, thereby improving the accuracy and effectiveness of the early warning.

[0111] In one specific implementation, the yaw calculation module M300 includes a channel association submodule. The channel association submodule is configured to: first, receive coordinates representing the ship's current physical position from the track determination module M200. ,in, This represents the optimized current physical position coordinates of the vessel. and These are the latitude and longitude coordinates of the current physical location, respectively. The waterway association submodule accesses the data acquisition module M100 to obtain a series of straight line segments. The data constitutes the centerline of the waterway. The waterway association submodule traverses each straight segment. And calculate the coordinates In the area containing the straight line segment The perpendicular projection point on an infinite straight line Then, the waterway association submodule determines the vertical projection point. Is it located on the line segment? The two endpoints and Between, among and The line segments are respectively The coordinates of the start and end endpoints. One way to determine this is to verify the coordinates of the endpoints. Pointing to the projection point The vector from the endpoint Pointing to the other end The dot product between vectors is non-negative, and the magnitude of the dot product is less than or equal to the line segment. The square of the length. If a unique straight line segment exists. If this condition is met, then the straight line segment It has been identified as the baseline waterway segment. In some other alternative implementations, the waterway association submodule may skip the above-mentioned projection point position determination and directly calculate the coordinates. To each straight segment shortest distance And select the shortest distance. The shortest straight segment is used as the reference channel segment. Through the above scheme, this embodiment can geometrically position the vessel on a specific segment of the channel centerline, laying the foundation for subsequent calculations of course deviation. Its beneficial effect is that it can quickly and accurately find the channel segment most relevant to the vessel's position, providing an accurate reference benchmark for subsequent yaw warnings.

[0112] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for early warning and identification of ship deviation when entering or leaving port, characterized in that, include: Acquire channel centerline data and yaw angle thresholds, which consist of multiple consecutive straight line segments; The system receives real-time data from the target vessel, including its current physical location coordinates, and determines the target vessel's course based on the data. Among the plurality of consecutive straight line segments, a reference waterway segment corresponding to the current physical position coordinates of the target vessel is determined; Calculate the angle between the flight path and the reference channel segment; Furthermore, when the included angle is greater than the yaw angle threshold, an electronic warning signal is generated.

2. The method according to claim 1, characterized in that, The step of determining the reference waterway segment includes: Calculate the vertical projection point of the current physical position coordinates of the target vessel onto the channel centerline represented by the channel centerline data, and determine the straight line segment where the vertical projection point is located as the reference channel segment.

3. The method according to claim 1, characterized in that, The step of determining the reference waterway segment includes: Calculate the distance from the current physical position coordinates of the target vessel to each of the multiple consecutive straight line segments, and determine the straight line segment with the smallest distance as the reference waterway segment.

4. The method according to claim 1, characterized in that, The step of determining the course includes: The current physical position coordinates and the previous physical position coordinates of the target vessel are obtained, and the course is determined based on the current physical position coordinates and the previous physical position coordinates.

5. The method according to claim 4, characterized in that, Prior to the step of determining the course, the method further includes: Receive an automatic identification system data sequence containing multiple consecutive physical location coordinates of the target vessel within a time window; Furthermore, the data sequence of the automatic identification system is subjected to smoothing filtering to obtain optimized multiple physical location coordinates; The flight path is determined based on two coordinates from the optimized multiple physical location coordinates.

6. The method according to claim 5, characterized in that, The smoothing filtering process employs either the Kalman filter algorithm or the weighted moving average algorithm.

7. The method according to claim 1, characterized in that, In the channel centerline data, each straight line segment is associated with an independent yaw angle threshold. The method further includes: after calculating the included angle, extracting the independent yaw angle threshold associated with the reference channel segment; Specifically, the step of comparing the included angle with the yaw angle threshold involves comparing the included angle with the extracted independent yaw angle threshold.

8. The method according to claim 1, characterized in that, The generated electronic warning signal is configured as a control signal to drive the operation of visual or auditory alarm devices.

9. The method according to claim 8, characterized in that, The visual alarm device is an electronic chart display terminal, and the control signal is used to drive the electronic chart display terminal to highlight or flash the icon of the target vessel.

10. A ship entry / exit port deviation early warning and identification system, characterized in that, include: The data acquisition module is configured to acquire channel centerline data consisting of multiple consecutive straight line segments and yaw angle thresholds, and to receive automatic identification system data containing the current physical position coordinates of the target vessel in real time. The track determination module, connected to the data acquisition module, is configured to determine the track direction of the target vessel based on the data from the automatic identification system. The yaw calculation module, connected to the data acquisition module and the track determination module, is configured to: determine, among the plurality of consecutive straight line segments, a reference channel segment corresponding to the current physical position coordinates of the target vessel; And, calculate the angle between the track direction and the reference channel segment; The warning generation module, connected to the yaw calculation module, is configured to: compare the included angle with the yaw angle threshold, and generate an electronic warning signal when the included angle is greater than the yaw angle threshold.

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