Bridge area navigation anti-collision early warning method and system

Abstract

The application discloses a bridge area navigation anti-collision early warning method and system, and relates to the technical field of ship navigation safety early warning. The method comprises the following steps: acquiring bridge area navigation data, ship dynamic data and bridge navigation constraint data; demarcating a bridge area early warning area according to a bridge hole, a bridge pier, a navigation mark and a recommended navigation route; predicting a ship position at multiple preset times according to a ship position, a ship speed and a ship heading; calculating a deviation change of the ship relative to the recommended navigation route or a bridge hole center line, and a remaining distance change between the ship and a bridge hole passing boundary; and determining a ship passing risk level. The application can demarcate different early warning areas according to actual bridge area navigation conditions, predict a future ship position in combination with a ship position, a ship speed and a ship heading, and determine a risk level according to a ship deviation change, a remaining passing distance change and AIS data update time, so that a corresponding early warning time window is selected and early warning information is output, and the timeliness and accuracy of bridge area navigation early warning are improved.

Description

Technical Field

[0001] This invention relates to the field of ship navigation safety early warning technology, specifically to a method and system for collision avoidance early warning in bridge areas. Background Technology

[0002] Navigation areas near bridges typically present challenges such as limited bridge span width, densely distributed bridge piers, fixed navigation marks, and the convergence of upstream and downstream waterways. When passing through bridge areas, vessels must follow recommended routes, navigable span positions, and on-site navigation mark guidance. If a vessel deviates from the recommended route, approaches the bridge pier collision avoidance zone, or inadvertently enters the navigation mark protection zone, it is likely to cause a collision with the bridge pier, a collision with the navigation mark, or obstruct the passage of other vessels.

[0003] Current bridge area vessel warning methods mostly rely on AIS data, radar data, or electronic fences for judgment. When a vessel's current position enters a preset area, the system outputs a reminder or alarm. This method can alert vessels entering dangerous areas, but it still has shortcomings in bridge area navigation scenarios: First, the warning area is mostly a fixed area, failing to consider the actual passage relationship between bridge openings, piers, navigation marks, and recommended routes; second, warning judgments are mostly based on whether the vessel's current position has entered a certain area, with insufficient judgment on the vessel's passage status in the near future; third, it does not adequately consider changes in the vessel's deviation from the recommended route or its approach to the bridge opening boundary, easily leading to warnings that are too early or too late; fourth, AIS data has an update interval, and if the judgment is not based on the AIS data update time, it may affect the accuracy of risk level determination. Summary of the Invention

[0004] This invention provides a method and system for collision avoidance warning in bridge areas. It can delineate different warning zones according to the actual navigation conditions in the bridge area, predict the future position of ships by combining the ship's position, speed, and course, and determine the risk level based on changes in ship deviation, changes in remaining passage distance, and AIS data update time. In this way, it can select the corresponding warning time window and output warning information, thereby improving the timeliness and accuracy of bridge area navigation warnings.

[0005] A method for collision avoidance early warning in bridge area navigation includes: acquiring bridge area navigation data, vessel dynamic data, and bridge navigation constraint data; delineating the bridge area early warning zone based on bridge spans, piers, navigation marks, and recommended routes; predicting the vessel's position after multiple preset time intervals based on the vessel's position, speed, and heading; calculating the vessel's deviation from the recommended route or bridge span centerline, as well as the change in the remaining distance between the vessel and the bridge span passage boundary; determining the vessel passage risk level based on the deviation change, the remaining distance change, and the AIS data update time; selecting the corresponding early warning time window according to the risk level and outputting the early warning information.

[0006] Furthermore, the bridge area warning zone includes at least one of the following: recommended route area, external alert area, navigation mark protection area, collision avoidance zone, and transition zone. Different bridge area warning zones correspond to different warning levels or warning rules.

[0007] Furthermore, the preset time includes at least two of 30 seconds, 60 seconds, 90 seconds, and 120 seconds, and the corresponding preset time is selected based on the distance between the vessel and the bridge opening, the vessel speed, or the warning area of ​​the bridge area.

[0008] Furthermore, the deviation is determined by the change in the lateral distance of the vessel at the current time and the predicted time relative to the recommended route or bridge centerline.

[0009] Furthermore, the remaining distance variation is determined by the minimum distance variation between the ship's outline and the bridge opening passage boundary or the collision avoidance zone boundary.

[0010] Furthermore, when the AIS data update time exceeds the preset time interval, the ship's current position is compensated based on the ship's most recent position, speed, and heading, and the ship's position is predicted based on the compensated position.

[0011] Furthermore, the corresponding warning time windows include: when the vessel is in the recommended route area and has not deviated from the recommended route, a passage confirmation time window is selected; when the vessel is in the external warning area and its speed is greater than the preset threshold, a route warning time window is selected; when the vessel shows a tendency to deviate from the recommended route, a track correction time window is selected; and when the predicted vessel position enters the collision avoidance zone or navigation mark protection zone, a collision avoidance warning time window is selected.

[0012] Furthermore, before issuing a warning, it is determined whether the same vessel has already issued a warning for the same bridge area within a preset time. If it has already issued a warning, it will not issue a warning again, or the frequency of repeated warnings will be reduced.

[0013] A bridge area navigation collision avoidance early warning system includes: a data acquisition module for acquiring bridge area navigation data, vessel dynamic data, and bridge navigation constraint data; an area division module for delineating bridge area early warning zones based on bridge spans, piers, navigation marks, and recommended routes; a vessel position prediction module for predicting vessel positions after multiple preset time intervals based on vessel position, speed, and heading; a risk assessment module for determining the deviation of vessels from the recommended route or bridge span centerline, the change in the remaining distance between vessels and the bridge span passage boundary, and determining the vessel passage risk level based on the deviation change, the remaining distance change, and the AIS data update time; and an early warning output module for selecting the corresponding early warning time window according to the risk level and outputting early warning information.

[0014] Furthermore, it also includes a vessel processing module, which is used to filter, lower the warning level, or raise the warning level of crossing vessels, law enforcement vessels, government vessels, engineering vessels, tugboats, extra-wide vessels, or passenger ships according to their type.

[0015] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0016] 1. By adopting the method of delineating bridge area warning zones based on bridge openings, piers, navigation marks, and recommended routes, the warning zones correspond to the actual navigation conditions of the bridge area. Instead of simply issuing warnings based on fixed ranges, this method can adapt to different navigation scenarios such as recommended route areas, navigation mark protection areas, and collision avoidance zones, thereby improving the pertinence of bridge area warning judgments.

[0017] 2. It can predict the ship's position after several preset times based on the ship's location, speed and course, and select the corresponding warning time window according to the risk level. It can judge the passage risk in advance before the ship enters the danger zone, reduce the problem of warning too late caused by judging only the current position, and avoid warning too early from affecting normal passage.

[0018] 3. By calculating the changes in the deviation of the vessel from the recommended route or the centerline of the bridge opening, as well as the changes in the remaining distance between the vessel and the bridge opening passage boundary, it is possible to determine whether the vessel is trending towards deviating from the recommended route, approaching the bridge opening boundary or the collision avoidance area, thereby improving the accuracy of the assessment of bridge area passage risks.

[0019] 4. By combining the AIS data update time to determine the vessel passage risk level, and by compensating the vessel's current position when the AIS data update time exceeds the preset time interval, the impact of untimely AIS data updates on vessel position prediction and early warning judgment can be reduced, thereby improving the reliability of early warning information.

[0020] 5. Before outputting early warning information, the present invention determines whether the same vessel has already output early warning information for the same bridge area within a preset time, which can reduce duplicate early warnings and reduce the interference of invalid alarms on on-site management and vessel passage.

[0021] 6. It can filter, lower or raise the warning level of crossing vessels, law enforcement vessels, official vessels, engineering vessels, towing vessels, extra-wide vessels or passenger vessels according to the type of vessel, so that the warning results are more in line with the needs of on-site management in the bridge area.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a flowchart of a bridge area navigation collision avoidance early warning method disclosed in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of a bridge area navigation collision avoidance early warning system disclosed in an embodiment of the present invention.

[0027] Figure label:

[0028] 10. Data Acquisition Module; 20. Area Division Module; 30. Ship Position Prediction Module; 40. Risk Assessment Module; 50. Early Warning Output Module; 60. Ship Processing Module; 70. Database; 80. Server. Detailed Implementation

[0029] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0030] This embodiment provides a collision avoidance early warning method for navigation in bridge areas, applicable to vessel traffic monitoring, route reminders, yaw warnings, and collision avoidance warnings within bridge navigation control areas. The method delineates the early warning area based on bridge spans, piers, navigation marks, and recommended routes; it predicts vessel positions after several preset time intervals using vessel position, speed, heading, and AIS data update time as input; then, based on changes in vessel deviation relative to the recommended route or bridge span centerline, and changes in the remaining distance between the vessel and the bridge span boundary, it determines the vessel traffic risk level and outputs early warning information according to the corresponding early warning time window selected based on the risk level.

[0031] This embodiment also provides a bridge area navigation collision avoidance early warning system, including a data acquisition module 10, an area division module 20, a vessel position prediction module 30, a risk assessment module 40, an early warning output module 50, and a vessel processing module 60 deployed on a server 80. The data acquisition module 10 is used to acquire bridge area navigation data, vessel dynamic data, and bridge navigation constraint data. The area division module 20 is used to delineate the bridge area early warning zone based on bridge openings, piers, navigation marks, and recommended routes. The vessel position prediction module 30 is used to predict the vessel's position after several preset time intervals based on the vessel's position, speed, and heading. The risk assessment module 40 is used to determine the vessel's deviation from the recommended route or bridge opening centerline, the change in the remaining distance between the vessel and the bridge opening passage boundary, and to determine the vessel passage risk level in conjunction with the AIS data update time. The early warning output module 50 is used to select the corresponding early warning time window according to the risk level and output early warning information. The ship processing module 60 is used to filter, lower the warning level, or raise the warning level of crossing ships, law enforcement ships, official ships, engineering ships, tugboats, ultra-wide ships, or passenger ships according to preset rules based on the ship type and its mission attributes. It should be noted that the shipborne terminal in each embodiment specifically refers to the multi-functional integrated system based on Beidou technology, i.e., the shipborne MIBT terminal, in the preferred embodiment. In this document, the two have the same, equivalent, or inclusive physical and logical meanings.

[0032] The following describes this solution in further detail with specific implementation methods. In this specific implementation, the Wuhan Yangtze River Bridge area is used as an example bridge area. For ease of description, the Wuhan Yangtze River Bridge is abbreviated as "Wu Bridge". Upstream refers to ships sailing upstream along the Yangtze River, while downstream refers to ships sailing downstream along the Yangtze River. Therefore, the Wu Bridge upstream navigation mark protection zone refers to the navigation mark protection zone in the Wuhan Yangtze River Bridge area corresponding to the upstream navigation direction, and the Wu Bridge downstream navigation mark protection zone refers to the navigation mark protection zone in the Wuhan Yangtze River Bridge area corresponding to the downstream navigation direction; the Wu Bridge upstream collision avoidance zone refers to the warning area related to collision avoidance of upstream ships before and after passing the Wuhan Yangtze River Bridge piers, and the Wu Bridge downstream collision avoidance zone refers to the warning area related to collision avoidance of downstream ships before and after passing the Wuhan Yangtze River Bridge piers. The above area names are only used to illustrate the bridge area division method in this implementation. When applied to other bridge areas, they can be named according to the corresponding bridge name, upstream direction, and downstream direction.

[0033] Example 1

[0034] This embodiment uses the Wuhan Yangtze River Bridge area as the navigation control scenario. This bridge area encompasses the waters between 3.7km and 1.7km of the middle reaches of the Yangtze River channel, with the Wuhan Yangtze River Bridge located at 2.5km of the middle reaches. According to the navigation restrictions, the restricted navigation zone for the Wuhan Yangtze River Bridge extends from 1.2km upstream to 0.8km downstream of the bridge. The Wuhan Yangtze River Bridge has nine spans, each 128m wide. Vessels travel upstream on the fourth span, between the fourth and fifth piers; vessels travel downstream on the sixth span, between the sixth and seventh piers.

[0035] Step S1: Obtain navigation data, vessel dynamic data, and bridge navigation constraint data for the bridge area.

[0036] The data acquisition module 10 establishes data connections with the maritime department's data platform, the waterway department's data platform, AIS equipment, shipborne MIBT terminals, Beidou terminals, and the regulatory platform to acquire bridge area navigation data, vessel dynamic data, and bridge navigation constraint data, respectively. Bridge area navigation data is released by the maritime department and includes electronic nautical chart data, navigation mark coordinate data, recommended route data, historical vessel track data, waterway boundary data, and bridge area regulatory rules data. Vessel dynamic data includes vessel MMSI, vessel position, speed, heading, track direction, and AIS data update time, collected by shipborne MIBT terminals, AIS receiving equipment, or Beidou terminals and transmitted back to server 80. Bridge navigation constraint data originates from bridge area navigation regulations released by the maritime department, bridge layer data provided by the waterway department, basic bridge information provided by bridge management units, and on-site navigation mark deployment data in the bridge area. This data includes bridge span locations, pier locations, navigation span numbers, span widths, restricted waterway boundaries, upstream and downstream traffic rules, navigation speed limits, and pier collision avoidance requirements.

[0037] After receiving and organizing the various types of data mentioned above, the data acquisition module 10 outputs them uniformly to the database 70. Specifically, the data acquisition module 10 first receives raw data from different data sources, and then merges the various types of data according to time information, spatial coordinates, ship identification, and data type. Subsequently, the raw data undergoes format conversion, field validation, coordinate unification, duplicate data removal, and missing data completion. The processed data is then organized into bridge area navigation data, ship dynamic data, and bridge navigation constraint data, respectively. Finally, the organized data is stored in the database 70. The database 70 classifies and stores the data and provides query access to the subsequent area division module 20, ship position prediction module 30, and risk assessment module 40.

[0038] Step S2: Delineate the bridge area warning zone based on the bridge openings, piers, navigation marks, and recommended routes.

[0039] In one implementation, the area division module 20 first reads the basic spatial data and constraint data for area division from the database 70. The basic spatial data includes at least bridge span location data, bridge pier location data, navigation mark coordinate data, recommended route coordinate data, and water area boundary coordinate data. The water area boundary data is formed by the water area boundary layer of the electronic waterway chart provided by the waterway department, the navigation restriction range data of the bridge area issued by the maritime department, and the bridge area management boundary data provided by the bridge management unit. For areas not covered or requiring correction in the above data, supplementary data is obtained through on-site measurement or surveying. The data acquisition module 10 performs coordinate unification, boundary closure check, and format conversion on the water area boundary data, and then stores it in the database 70. The area division module 20 reads the data to determine the outer boundary, transition zone boundary, and restricted water area boundary of the bridge area warning zone. The constraint data includes at least the restricted water area boundary, up and down traffic rules, navigation speed limit requirements, and bridge pier collision prevention requirements. The area division module 20 processes the bridge arch location data and pier location data read from the database 70 to determine the spatial relationship between the center point of each bridge arch and the pier; it processes the navigation mark coordinate data to determine the coordinate position of each buoy and their connecting relationships; it processes the recommended route coordinate data to extract the center line and boundary line of the recommended route; and it processes the water boundary coordinate data and restricted water boundary data to determine the navigation control range of the bridge area and the outer boundary of the area.

[0040] After completing the above data reading, the area division module 20 spatially divides the bridge area waters based on the bridge arch center point, pier coordinates, buoy coordinates, and recommended route boundaries. Specifically, the area division module 20 first uses the recommended route centerline as a reference and expands to the left and right sides by a preset width to form a recommended route area; then, the area between the outer edge of the recommended route area and the water boundary is used as an external warning area to alert vessels that deviate from the recommended route but have not yet entered the high-risk area; then, using the line connecting the buoys or the line connecting the buoys and the piers as the centerline, it extends to both sides by a preset distance to form a navigation mark protection area; then, the waters within a certain range around the piers are used as a collision avoidance zone to provide collision warnings to vessels approaching the piers; finally, the waters outside the above areas but still within the navigation control range of the bridge area are divided into a transition zone for background recording or low-level warnings to vessels.

[0041] The boundaries of the recommended navigation route area are directly determined by the boundary coordinates of the recommended navigation route in database 70, or calculated based on the centerline of the recommended navigation route and the preset navigation route width. The boundaries of the external warning area are jointly defined by the outer boundary of the recommended navigation route area and the water boundary. The boundaries of the buoy protection area are determined by the buoy coordinates and the lines connecting adjacent buoys. The boundaries of the collision avoidance area are jointly determined by the pier coordinates and their safe distance from the surrounding area. The boundaries of the transition area are jointly formed by the outer edges of the recommended navigation route area, the external warning area, the buoy protection area, and the collision avoidance area. Through the above methods, the area division module 20 can automatically divide the bridge area warning area based on the basic data read from database 70, and output the division results to database 70 for subsequent use by the vessel position prediction module 30 and the risk assessment module 40.

[0042] In this embodiment, the upstream and downstream boundaries are defined at 3.7km and 1.7km along the middle reaches of the Yangtze River channel. Using navigation marks and bridge piers as nodes, the area is divided into a recommended navigation route zone, an external warning zone, a navigation mark protection zone, a collision avoidance zone, and a transition zone. The recommended navigation route zone corresponds to a green area, the external warning zone to a white area, the transition zone to a yellow area, and the navigation mark protection zone and collision avoidance zone to red areas. The monitoring platform displays all electronic fences for the bridge area and distinguishes the warning areas of each bridge area with different colors.

[0043] The recommended navigation route area is determined based on the overlay of three days' historical trajectories from the bridge area. The recommended route extends 25 meters to the left and right of the bridge opening's center point, with a width of 50 meters. When an upstream vessel enters the bridge area with a speed of at least 4 km / h, it is identified as an upstream vessel based on its track direction, and an upstream recommended route is provided. When a downstream vessel enters the bridge area with a speed of at least 12 km / h, it is identified as a downstream vessel based on its track direction, and a downstream recommended route is provided. The recommended route can be highlighted on the ship's MIBT terminal electronic river chart or displayed by default on the monitoring platform.

[0044] The external warning zone is the area between the shoreline and the navigational aid protection zone, divided into the left bank external warning zone and the right bank external warning zone. Vessels in this zone include berthed vessels and vessels underway. When a vessel underway has a speed greater than 4 km / h and has not entered the recommended route area, a route warning is triggered, reminding the vessel to enter the recommended route as soon as possible and pass through the designated bridge openings.

[0045] The navigational aid protection zone extends 20 meters to both sides of the centerline, which is the line connecting the buoys or the line connecting the buoy and the bridge pier. This 20-meter width is used to allow for the width of vessels and the safe distance of navigational aids. The left bank upstream navigational aid protection zone includes the area before upstream vessels pass the bridge and the area after upstream vessels pass the bridge. The area before upstream vessels pass the bridge is 350 meters to 800 meters downstream of the bridge, with a channel length of 2.15 km to 1.7 km in the middle reaches, and the centerline is the line connecting the Wuqiao Shangshui #1 white buoy and the 4th pier. The area after upstream vessels pass the bridge is 0 meters to 1.2 km upstream of the bridge, with a channel length of 3.7 km to 2.5 km in the middle reaches, and the centerline is the line connecting the Wuqiao Shangshui #2 white buoy and the 4th pier. The intermediate channel navigation mark protection zone extends from 350m downstream of the bridge to 1.2km upstream, with a channel length of 3.7km to 2.15km in the middle reaches. The centerline passes the left and right navigation buoys of the Wuqiao Bridge, the Wuqiao launching buoy #2 (white), the Wuqiao launching buoy #1 (white), and the 5th and 6th piers. Since there is no navigation between the 5th and 6th piers, this area is included in the intermediate channel navigation mark protection zone. The right bank downstream navigation mark protection zone extends from 0m to 1.2km upstream of the bridge, with a channel length of 3.7km to 2.5km in the middle reaches. The centerline is the line connecting the Wuqiao launching buoy #3 (red), the Wuqiao launching buoy #2 (red), the Wuqiao launching buoy #1 (red), and the 7th pier.

[0046] The collision avoidance zones are designated to address the risk of vessels colliding with the 4th and 7th piers, and are divided into upstream and downstream collision avoidance zones. For upstream vessels, the collision avoidance zone before passing the bridge extends from 0m to 350m downstream of the bridge, with a channel length of 2.5km to 2.15km in the middle reaches of the waterway. The centerline is the line connecting the Wuqiao upstream buoy #1 (white buoy) and the 4th pier. For downstream vessels, the collision avoidance zone extends from 0m to 250m upstream of the bridge, with a channel length of 2.75km to 2.5km in the middle reaches of the waterway. The centerline is the line connecting the Wuqiao downstream buoy #1 (red buoy) and the 7th pier. A collision warning is triggered when a vessel is predicted to enter the collision avoidance zone.

[0047] The transition zone encompasses the bridge area excluding the recommended route area, external warning area, buoy protection zone, and collision avoidance zone. It is divided into an upstream transition zone and a downstream transition zone, with a channel length ranging from 3.7 km to 1.7 km in the middle reaches. When a vessel is predicted to enter the transition zone, the system records this information in the background. If the vessel continues to approach the buoy protection zone or collision avoidance zone, the warning level is raised based on the risk level.

[0048] Step S3: Predict the ship's position after several preset times based on the ship's position, speed, and course.

[0049] The vessel position prediction module 30 reads the vessel's current longitude, latitude, speed, and heading, and predicts the future vessel position according to at least two preset time intervals of 30 seconds, 60 seconds, 90 seconds, and 120 seconds. The preset time intervals are selected based on the vessel's distance from the bridge opening, its speed, or the bridge area warning zone it is located in. When the vessel is far from the bridge opening and within the recommended navigation route zone, 90 seconds and 120 seconds can be selected; when the vessel is close to the navigation mark protection zone or collision avoidance zone, 30 seconds and 60 seconds can be selected; when the vessel is within the external warning zone and its speed is low, 60 seconds and 90 seconds can be selected.

[0050] The future position of a ship can be calculated using the following formula, assuming the ship's current latitude is 1. The current longitude is The speed is The heading is The predicted time is Choose 30 seconds, 60 seconds, 90 seconds, or 120 seconds, with the Earth's radius being... Before calculation, first set the current latitude. The current longitude is ,course All measurements are converted to radians, with speed v in m / s and Earth radius R in m. The latitude and longitude increments of the ship at the predicted time are: , Then predict latitude Predicting longitude ,in, and All results are in radians, which can be converted back to degrees during output.

[0051] The above calculations can be performed using approximate latitude and longitude conversions or geodetic distance calculations. For short-distance bridge area predictions, the prediction range is typically less than 1 km, and the above calculations are sufficient to meet the early warning needs of bridge areas. The vessel position prediction module updates its prediction results every 5 to 30 seconds. If the shipborne MIBT terminal uses a high-frequency backhaul channel, the update interval can be 5 seconds; if AIS data is used directly, the update interval can be 30 seconds.

[0052] Step S4: Calculate the deviation of the vessel from the recommended route or the centerline of the bridge opening, as well as the change in the remaining distance between the vessel and the bridge opening passage boundary.

[0053] The deviation is determined by the change in the lateral distance of the vessel at the current time and the predicted time relative to the centerline of the recommended route or bridge opening. The recommended route or bridge opening centerline is stored as a line segment, and the vertical distances from the vessel's current position and predicted position to this centerline are denoted as follows: and .like Greater than This indicates that the vessel is trending away from the recommended route or the centerline of the bridge opening; if Less than or equal to This indicates that the vessel is approaching or remaining near the recommended route. The calculation method is as follows: ,in, This refers to deviations or changes.

[0054] The change in remaining distance is determined by the change in the minimum distance between the ship's outline and the bridge opening passage boundary or collision avoidance zone boundary. The ship's outline can be approximated as a rectangle based on its length and beam. The two sides of the beam direction serve as the basis for determining proximity to the bridge opening passage boundary. Specifically, a two-dimensional rectangular envelope is established based on the ship's current latitude and longitude, length, beam, and heading. The four vertices and four boundary segments of this rectangular envelope are extracted. The geometric vertical projection distances and endpoint distances from each vertex and segment to the bridge opening passage boundary or collision avoidance zone boundary segment are compared, and the minimum value selected is taken as the minimum distance between the ship's outline and the boundary. If the ship's beam data is unavailable, a default beam can be used. For example, the default beam for cargo ships is 8m to 16m, for passenger ships it is 6m to 12m, and for engineering vessels it is 10m to 20m. The remaining distance is the minimum distance from the bridge opening passage boundary or collision avoidance zone boundary to the ship's outline. The current remaining distance is denoted as... The predicted remaining distance is denoted as The calculation method is as follows: ,in, This shows the change in the remaining distance.

[0055] when Greater than 0 and A value less than 0 indicates that the vessel is deviating from the recommended route and approaching the bridge opening boundary or collision avoidance zone boundary, increasing the risk level. Less than or equal to 0 and When the value is greater than or equal to 0, it indicates that the ship is not showing a tendency to approach the danger boundary, and the risk level is reduced or remains the same.

[0056] Step S5: Determine the vessel passage risk level based on the changes in deviation, changes in remaining distance, and AIS data update time.

[0057] The risk assessment module 40 determines the vessel's passage risk level based on the bridge area warning zone where the vessel is located, changes in deviation, changes in remaining distance, and AIS data update time. Risk levels can be categorized into passage confirmation level, route alert level, track correction level, and collision warning level.

[0058] When the vessel is in the recommended route area, and Less than or equal to 0, When the value is greater than or equal to 0 and the AIS data update time does not exceed the preset time interval, it is determined to be a passage confirmation level. When the vessel is in the external warning zone, the speed is greater than 4 km / h, and the predicted position has not entered the collision avoidance zone or the navigation mark protection zone, it is determined to be a route warning level. When the predicted position of the vessel enters the navigation mark protection zone, or A value greater than 0 and the vessel approaching the navigation mark protection zone is defined as a track correction level. This level is further defined when the vessel's predicted position enters the collision avoidance zone, or... When the distance remains below 0 and the remaining distance is between 20m and 50m, it is determined to be a collision warning level. When a vessel is in the transition zone, the system will silently record the information by default without triggering an active alarm, or it will determine the vessel in the transition zone to the alert level and continuously monitor the vessel's tendency to move towards the collision zone or navigation mark protection zone.

[0059] When the AIS data update time exceeds a preset time interval, the ship's current position is compensated based on its most recent position, speed, and heading, and a position prediction is made based on the compensated position. The preset time interval can be between 10 and 45 seconds, preferably 30 seconds. The compensation time is the difference between the current time and the time of the most recent AIS data update, calculated as follows: ,in, To compensate for the increase in latitude and longitude, , The compensated ship's current position latitude and longitude coordinates, The latitude and longitude coordinates of the ship's position in the most recent AIS data are used for calculation. Before calculation, the ship's position in the most recent AIS data is first... latitude, longitude and heading All converted to radians, speed The unit is m / s, the unit of Earth's radius R is m, and the calculation method for latitude and longitude compensation increment is as follows: , ,in, for latitude value, This is the difference between the current time and the time of the most recent AIS data.

[0060] During bridge area testing, it was found that when the AIS update frequency is 30 seconds, if only judging whether the predicted route intersects with the area boundary, warnings may sometimes be missed because the predicted route does not intersect with the area edge line. Therefore, this embodiment uses the method of predicting the vessel's position entering the bridge area warning zone for judgment, and combines it with AIS data update time for position compensation. In this way, both missed warnings and judgment errors caused by AIS data intervals can be reduced.

[0061] Step S6: Select the corresponding warning time window according to the risk level and output the warning information.

[0062] The early warning output module 50 selects the corresponding early warning time window based on the risk level. When the vessel is in the recommended route area and has not deviated from the recommended route, a passage confirmation time window is selected; when the vessel is in the external warning area and its speed is greater than a preset threshold, the preset threshold can be set according to the actual navigation regulations and tidal characteristics of the bridge area, and its value range is usually from 2km / h to 8km / h, preferably 4km / h, a route warning time window is selected; when the vessel has a tendency to deviate from the recommended route, a track correction time window is selected; when the predicted vessel position enters the collision avoidance zone or navigation mark protection zone, a collision avoidance warning time window is selected.

[0063] The passage confirmation window can be 90 to 120 seconds, used to confirm whether the vessel is staying within the recommended route. The route reminder window can be 60 to 90 seconds, used to remind vessels in the external reminder zone to enter the recommended route as soon as possible. The track correction window can be 60 to 90 seconds, used to prompt vessels to adjust their course in a timely manner. The collision warning window can be 30 to 60 seconds, used to issue a higher level of warning when a vessel approaches a bridge pier, collision zone, or buoy protection zone. For vessels with high speeds or rapidly decreasing remaining distance, shorter time windows should be prioritized; for vessels with low speeds and far from the bridge opening passage boundary, longer time windows can be selected.

[0064] The warning information includes the vessel's MMSI, vessel name, vessel type, current latitude and longitude, predicted latitude and longitude, speed, course, name of the bridge warning area, risk level, warning time window, warning distance, and reason for the warning. Warning information can be output via voice broadcast and text pop-up windows through the ship's MIBT terminal, or it can be pushed to the monitoring platform, where it will be displayed in a pop-up window and recorded. Route reminders may suggest "Enter the recommended route as soon as possible and pass through the designated bridge openings"; track correction may suggest "Correct course and avoid entering the navigation mark protection zone"; collision warnings may suggest "The vessel is predicted to enter the collision zone; please adjust course or speed immediately."

[0065] Before outputting a warning message, the warning output module 50 determines whether the same vessel has already issued a warning message for the same bridge area warning zone within a preset time. If it has already issued a warning, it will not issue a repeat warning, or the frequency of repeated warnings will be reduced. The preset time can be from 30 seconds to 300 seconds, preferably 120 seconds. The repeat determination fields include the vessel's MMSI, the bridge area warning zone number, the risk level, and the warning time. If the same vessel has already issued a collision warning for the same collision zone within 120 seconds, and the risk level has not increased, it will not issue a warning again; if the current risk level is higher than the risk level at the time of the previous warning, a new warning message will be issued immediately.

[0066] The vessel processing module 60 processes vessels according to their type. For targets such as vessels crossing the waterway, ferries, patrol boats, law enforcement vessels, government vessels, and engineering vessels, the system can filter or lower the warning level based on their actual operational tasks. For higher-risk vessels such as towed vessels, extra-wide vessels, and passenger ships, the warning level can be increased or a shorter warning time window can be selected in advance. In tests conducted in the Wuhan Yangtze River Bridge waters, the alarm trigger warning zone 800m below the upper white buoy was adjusted and reduced to a 300m alarm trigger warning zone, and targets such as ferries, patrol boats, law enforcement vessels, and engineering vessels crossing the waterway were filtered. After the adjustment, the system's ability to distinguish between different vessel types and passage behaviors was improved, enabling it to separate normal passage from non-compliant bridge crossing behaviors.

[0067] In this embodiment, the monitoring platform records the alarm distance and vessel speed. Test records show that the distance between the vessel and the warning point when the alarm is triggered ranges from 98.5m to 563.2m, with an average distance of approximately 165m. Most alarms occur within the range of 100m to 200m. The vessel speed at which the alarm is triggered ranges from 0 knots to 10 knots (equivalent to 0 km / h to 18.52 km / h), with an average speed of approximately 5.4 knots (equivalent to 10 km / h). This distance range allows sufficient time and space for the crew to take evasive action.

[0068] Example 2

[0069] The difference between this embodiment and Embodiment 1 is that Embodiment 1 uses at least two preset times of 30 seconds, 60 seconds, 90 seconds and 120 seconds as the main warning time window, while this embodiment adjusts the preset time to at least two of 60 seconds, 90 seconds, 120 seconds and 150 seconds based on the bridge length, ship speed and test results.

[0070] During testing in the waters of the Wuhan Yangtze River Bridge, different early warning methods were used for two time periods. The first time period used line-of-sight collision prediction, triggering an early warning when the predicted position of a vessel intersects the area boundary. The second time period used area collision prediction, triggering an early warning when the predicted position of a vessel is within the warning area. Testing revealed that with an AIS update frequency of 30 seconds, relying solely on the intersection of the predicted line and the area boundary could result in the predicted line not intersecting with the area edge line, thus missing the early warning information. Therefore, this embodiment adjusts the early warning method to trigger the corresponding warning when the predicted position of a vessel is within the navigation mark protection zone or collision avoidance zone after 60, 90, 120, or 150 seconds.

[0071] The area division in this embodiment is the same as in Embodiment 1, still using bridge openings, piers, navigation marks, and recommended routes to delineate the recommended route area, external warning area, navigation mark protection area, collision avoidance area, and transition area. The difference is that the vessel position prediction module 30 adds a 150-second prediction point based on the water length and vessel speed, enabling vessels entering the bridge area from a distance to receive route warnings earlier; for vessels already approaching the left and right navigation buoys of the Wuqiao Bridge, the Wuqiao launching buoy #2, or the bridge opening passage boundary, the prediction time is shortened.

[0072] In one adjustment method, regarding the collision warning issue in the area after upstream vessels pass the bridge, specifically the portion of the upstream navigation mark protection zone on the left bank, the area division module 20 adjusts the length of the entire area. Since there is no collision risk when vessels continue normal navigation along the shore after passing the Wuqiao Shangshui #2 white buoy, the length of this area after upstream vessels pass the bridge is adjusted from 1150m to 700m. After the area length adjustment, the vessel position prediction module 30 still predicts vessel positions at 60 seconds, 90 seconds, 120 seconds, and 150 seconds, but the risk assessment module 40 only triggers a warning when the predicted vessel position enters the adjusted navigation mark protection zone.

[0073] In another adjustment, regarding the early warning issue in the intermediate navigation mark area of ​​the Wuqiao Bridge, the early warning output module 50 selects different early warning time windows based on the vessel's location. After a vessel enters the port and starboard navigation buoys of the Wuqiao Bridge, the prediction time is changed to 30 seconds later; after the vessel passes the Wuqiao Bridge launch buoy #2, the prediction time is changed to 60 seconds later. This approach avoids premature predictions of entering the intermediate navigation mark protection zone due to an excessively long 120-second prediction time when the vessel is normally adjusting its course to align with the navigation hole, thus reducing unnecessary early warnings.

[0074] This embodiment can also add external alert zone filtering rules. When a vessel crosses the upstream collision avoidance zone and the left bank upstream navigation mark protection zone, if the vessel is in the external alert zone and its predicted position enters the navigation mark protection zone or collision avoidance zone, but its track is for crossing, ferry operations, or official business, the vessel processing module 60 may not output a warning, or may reduce the warning level to be recorded in the background. This rule applies to vessel types such as crossing vessels, ferries, patrol boats, law enforcement vessels, and engineering vessels.

[0075] Compared to Embodiment 1, this embodiment makes the early warning judgment more suitable for the characteristics of traffic conditions in the bridge area by changing the preset time and area length. Embodiment 1 is more suitable for short-term early warnings near the bridge opening, while Embodiment 2 is more suitable for providing advance warnings to vessels in longer bridge areas or at greater distances. The two implementation methods can be used individually or in combination based on the bridge area length, speed distribution, and alarm results.

[0076] Example 3

[0077] This embodiment is an extended application scenario, applying the methods of Embodiments 1 and 2 to other restricted bridge areas. In this embodiment, the data acquisition module 10 acquires the bridge openings, piers, navigation marks, water boundaries, recommended routes, vessel dynamic data, and navigation rules of the target bridge area. Since different bridges have different opening widths, navigation opening locations, upstream and downstream restrictions, and navigation mark deployments, the area division module 20 delineates areas based on the coordinates of nearby buoys and piers for each bridge. Each bridge area can use the coordinates of nearby buoys and piers as nodes to delineate recommended route areas, external warning areas, navigation mark protection areas, collision avoidance areas, and transition areas.

[0078] For bridge areas with wide spans, a navigation channel width of 40m to 80m is recommended; for bridge areas with narrow spans and narrow pier spacing, a navigation channel width of 30m to 60m is recommended. Navigational aid protection zones can be defined by extending 15m to 30m on each side of the line connecting the buoys or the line connecting the buoys and the piers. Collision avoidance zones can be defined within a range of 0m to 500m upstream or downstream of the piers. External warning zones can be set between the shoreline and the navigational aid protection zone. Transition zones are navigable waters other than the areas mentioned above.

[0079] For bridge areas with high traffic density, the early warning output module 50 can shorten the repetitive early warning judgment time to 30 to 120 seconds; for bridge areas with low traffic density, it can be 120 to 300 seconds. For bridge areas with more than 250 vessels per day, the system can increase the judgment frequency of track correction level and collision avoidance warning level, allowing the vessel position prediction module 30 to refresh the prediction results every 5 to 10 seconds; for bridge areas with less than 100 vessels per day, the prediction results can be refreshed every 10 to 30 seconds.

[0080] During the extended testing of the Wuhan Yangtze River Bridge, from November 21 to December 3, 2025, a total of 3,150 vessels navigated the bridge waters, and 156 collision avoidance alarms were recorded. The alarm distance ranged from 98.5m to 563.2m, with an average distance of approximately 165m; the speed of the vessels triggering the alarms ranged from 0 knots to 10 knots, with an average speed of approximately 5.4 knots. This test data can serve as a reference for initial parameter settings in other bridge areas. For new bridge areas, this parameter range can be used initially, and then the recommended route width, collision avoidance zone length, buoy protection zone length, and warning time window can be adjusted based on actual alarm records.

[0081] The system layout in this embodiment can be centralized or distributed. In a centralized layout, the data acquisition module 10, area division module 20, ship position prediction module 30, risk assessment module 40, early warning output module 50, and ship processing module 60 are all located within the shore-based server 80 and displayed uniformly by the monitoring platform. In a distributed layout, a portion of the data acquisition module 10 is located within the shipborne MIBT terminal or Beidou terminal, a portion of the ship position prediction module 30 is located within the shore-based server 80, and the early warning output module 50 is located within both the shipborne terminal and the monitoring platform. Communication between the shipborne terminal and the shore-based server 80 occurs via a mobile communication network, AIS link, Beidou link, or dedicated wireless link.

[0082] Example 1 provides a complete method for a single bridge area; Example 2 provides a warning time window and area length adjustment method; Example 3 extends the same method to multiple bridge areas and adjusts parameters according to the bridge opening width, vessel flow density, and navigation mark deployment of different bridge areas. All three implementation methods delineate the bridge area warning zone using bridge openings, piers, navigation marks, and recommended routes, and determine the risk level based on the future vessel position, deviation changes, remaining distance changes, and AIS data update time.

[0083] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0084] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0085] Those skilled in the art will also understand that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps described above are generally described in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in alternative ways for each specific application; however, such implementation decisions should not be construed as departing from the scope of this disclosure.

[0086] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied in hardware, software modules executed by a processor, or a combination thereof. The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. The ASIC can reside in a user terminal. Alternatively, the processor and storage medium can exist as discrete components in the user terminal.

[0087] For software implementation, the techniques described in this application can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described in this application. This software code can be stored in memory units and executed by a processor. The memory units can be implemented within the processor or outside the processor; in the latter case, they are communicatively coupled to the processor via various means, as is well known in the art.

[0088] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A method for collision avoidance early warning in bridge area navigation, characterized in that, Includes the following steps: Acquire navigation data, vessel dynamic data, and bridge navigation constraint data for the bridge area; The bridge area warning zone is delineated based on the bridge openings, piers, navigation marks, and recommended routes; Predict the ship's position at several preset times based on the ship's location, speed, and course; Calculate the changes in the ship's deviation from the recommended route or bridge opening centerline, as well as the changes in the remaining distance between the ship and the bridge opening passage boundary; The vessel passage risk level is determined based on changes in deviation, changes in remaining distance, and AIS data update time. Select the corresponding warning time window according to the risk level and output the warning information.

2. The method as described in claim 1, characterized in that, The bridge area warning zone includes at least one of the following: recommended route area, external alert area, navigation mark protection area, collision avoidance zone, and transition zone. Different bridge area warning zones correspond to different warning levels or warning rules.

3. The method as described in claim 1, characterized in that, Multiple preset times include at least two of 30 seconds, 60 seconds, 90 seconds, and 120 seconds. The corresponding preset time can be selected based on the distance between the vessel and the bridge opening, the vessel speed, or the warning area of ​​the bridge area.

4. The method as described in claim 1, characterized in that, The deviation is determined by the change in the lateral distance of the vessel at the current time and the predicted time relative to the recommended route or bridge centerline.

5. The method as described in claim 1, characterized in that, The change in remaining distance is determined by the minimum change in distance between the ship's outline and the bridge opening passage boundary or the collision avoidance zone boundary.

6. The method as described in claim 1, characterized in that, When the AIS data update time exceeds the preset time interval, the ship's current position is compensated based on the ship's most recent position, speed and heading, and the ship's position is predicted based on the compensated position.

7. The method as described in claim 1, characterized in that, The corresponding warning time windows are as follows: when the vessel is in the recommended route area and has not deviated from the recommended route, select the passage confirmation time window; when the vessel is in the external warning area and its speed is greater than the preset threshold, select the route warning time window; when the vessel is showing a tendency to deviate from the recommended route, select the track correction time window; and when the predicted vessel position enters the collision avoidance zone or navigation mark protection zone, select the collision avoidance warning time window.

8. The method as described in claim 1, characterized in that, Before issuing a warning, determine whether the same vessel has already issued a warning for the same bridge area within a preset time. If it has, do not issue a warning again, or reduce the frequency of repeated warnings.

9. A bridge area navigation collision avoidance early warning system, employing the bridge area navigation collision avoidance early warning method as described in any one of claims 1 to 8, characterized in that, include: The data acquisition module is used to acquire navigation data in the bridge area, vessel dynamic data, and bridge navigation constraint data. The area division module is used to delineate bridge area warning zones based on bridge openings, piers, navigation marks, and recommended routes. The ship position prediction module is used to predict the ship's position after several preset time intervals based on the ship's position, speed, and course. The risk assessment module is used to determine the deviation of the vessel from the recommended route or bridge opening centerline, the change in the remaining distance between the vessel and the bridge opening passage boundary, and to determine the vessel passage risk level based on the deviation change, the remaining distance change, and the AIS data update time. The early warning output module is used to select the corresponding early warning time window according to the risk level and output early warning information.

10. The system as described in claim 9, characterized in that, It also includes a ship processing module, which is used to filter, lower the warning level or raise the warning level of crossing ships, law enforcement ships, government ships, engineering ships, towing ships, ultra-wide ships or passenger ships according to their type.

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