Anchoring ship safety early warning dynamic sensing method and system

Abstract

The invention discloses a safety early warning dynamic sensing method and system for an anchored ship, is used for guaranteeing the safety of the anchored ship in a complex coastal anchored ground with a limited water area, and relates to the technical field of sailing and maritime safety guarantee. Modeling is carried out by accurately calculating potential complex related variables inside and outside an anchored ship such as the length of an anchor chain, the water depth of an anchoring ground, the ship size, the positioning precision, the starting performance of a main engine and the influence of a limited water channel on the maneuvering characteristics of the ship, multiple static and dynamic factors of the ship are fully considered, and the accuracy of a risk sensing model is improved. And the dynamic sensing model dynamically changes along with different ship parameters and submarine topographies. An empirical result shows that effective safety early warning information can be provided for sailing and anchoring ships in the water transportation means when the ships are about to enter or pass through the restricted coastal anchoring ground, safe navigation and decision making of the ships are facilitated, and the sailing and anchoring safety of the ships is improved.

Description

Technical Field

[0001] The present invention relates to the field of navigation and maritime technology, and in particular to a method and system for dynamic sensing of safety early warning of an anchored ship. Background Art

[0002] In order to avoid potential collision risks and accidents in restricted navigation waters, ships at sea should maintain a sufficient safety distance. Especially for anchored ships, due to their large starting inertia, large anchored ships may need longer preparation time to start the engine until they reach the speed required to overcome their own inertia; during the period when the main engine of the anchored ship starts and overcomes its own inertia, the anchored ship's own engine has not yet provided forward power, so it is regarded as an unpowered floating object on the water. However, in anchored waters with very complex water depth and terrain, anchored ships are often seriously disturbed by the external environment, resulting in the potential danger of colliding with other anchored ships. Therefore, it is very important to provide a safe perception and warning range for anchored ships and dynamically perceive the potential risks of the surrounding environment. The motion trajectory of anchored ships based on the turning radius can be used as a warning reference for the perception of potential collision risks, and can further help ship drivers perceive potential collision risks. The safe turning waters of anchored ships are warning areas to keep anchored ships safe; all ships at sea should stay away from this area, or avoid entering this area, which is an important buffer zone to ensure the safety of anchored ships.

[0003] Maritime traffic safety may be affected by the size of ocean-going vessels, waterway environment, ship maneuverability, and efficient communication and cooperation between different ships. With the rapid development of the manufacturing industry, the size and volume of ships are also developing towards large-scale, resulting in a sharp increase in the density of traffic flow in specific waters and waterways, and the availability of marine waterway resources is limited. In addition, the construction and expansion of coastal port anchorages are also difficult to adapt to the rapid development of the shipbuilding industry. Busy maritime traffic means that the original oceans and inland waterways have become crowded and restricted, which may lead to more potential maritime risks and accidents. A large number of ocean-going ships also means that ports and anchorages are more crowded. Those ships that cannot approach berths must sail to coastal anchorages to wait for port arrangements and berthing time. Especially in recent years, with the substantial increase in the density of water traffic flow, the daily flow of ships entering and leaving these restricted coastal ports and anchorages has produced a busy and complex water traffic flow distribution pattern. On the other hand, due to the influence of factors such as the professional skills and working status of the ship driver himself, coupled with the complexity of the ship's anchoring operation, the potential safety risks of anchored ships have further increased. Relevant studies at home and abroad have shown that most ship collision risks and accidents occur in restricted waters of coastal port channels. In addition, many ships drift or anchor at will in busy seaports from time to time. This arbitrary anchoring operation, coupled with the high density of ships underway and at anchor, may result in limited operating space between ships and make it more difficult to calculate the safe maneuvering of ships leaving the anchorage or preparing to anchor. These uncertain factors will lead to collision accidents of ships. Therefore, it is urgent to establish a risk warning method to ensure the safety of anchored ships. Summary of the invention

[0004] In order to accurately perceive and identify collision risks and reduce marine accidents in restricted anchorage waters, the present invention proposes a dynamic perception method and system for safety early warning of anchored ships. Considering the length of anchor chain, water depth of anchorage, ship type, ship positioning accuracy, ship main engine startup performance and the influence of restricted waters on ship maneuverability, the method models the internal and external potential complex related variables of anchored ships by accurately calculating the length of anchor chain, water depth of anchorage, ship size, positioning accuracy, main engine startup performance and the influence of restricted waterways on ship maneuverability. This dynamic perception model changes with different ship parameters and seabed topography. The effectiveness and practicality of the dynamic safety perception model created are proved by using the dynamic and static data of real anchored ships extracted from the ship-borne automatic identification system. The empirical results show that the present invention can provide safety early warning information for all types of sailing and anchored ships in water transportation vehicles when they are about to enter or pass through restricted coastal anchorages. The present invention contributes to safe navigation and decision-making of ships.

[0005] To this end, the present invention provides the following technical solutions:

[0006] The present invention provides a method for dynamic perception of safety early warning of an anchored ship, comprising the following steps:

[0007] Obtain AIS static and dynamic data information of ports including anchored ships;

[0008] According to the navigation status of the ship recorded by AIS, the information of anchored ships in specific port waters is screened, and the ship model and size information of the anchored ships is obtained; according to the nautical chart information of the port waters, the data information of the topography and external environmental conditions of the anchored waters of the port is screened;

[0009] Calculate the anchor chain length, anchor ship positioning error, anchor position positioning error, anchorage depth, ship size, main engine starting performance and the impact of restricted waterways on ship maneuverability based on the ship model, size information, anchored ship anchoring waters terrain and external environmental conditions data;

[0010] Based on the influence of anchor chain length, anchored ship positioning error, anchor position positioning error, anchorage water depth, ship size, main engine starting performance and restricted waterway on ship maneuverability, the safe perception turning radius of anchored ship is obtained;

[0011] Dynamic safety warning of anchored ships is carried out based on the safety perception turning radius of anchored ships.

[0012] Further, the anchor chain length is calculated, including:

[0013] Establish an accurate calculation model for the anchor chain length of a single-anchor ship; divide the anchor chain length of the anchored ship into a suspended anchor chain part suspended in the water and a flat anchor chain part on the seabed that provides additional grip; calculate the horizontal projection anchor chain length of the suspended anchor chain part. The anchor chain length of a single-anchor ship is equal to the horizontal projection of the suspended chain plus the length of the flat anchor chain on the seabed;

[0014] The calculation formula of the suspension chain length is as follows:

[0015]

[0016] The formula for calculating the length of the tile chain is as follows:

[0017]

[0018] The total length L of the chain is calculated as follows:

[0019]

[0020] Among them, T o represents the horizontal external force acting on the hull, w c Indicates the weight of the anchor chain per unit length in water; L c represents the length of the catenary part, and H represents the length from the anchor hole to the seabed; where Lh Indicates the length of the flat anchor chain, w a represents the weight of the anchor chain per unit length in the air, η a and η c They represent the holding coefficient of the anchor and the holding coefficient of the anchor chain respectively.

[0021] Furthermore, the positioning error of the anchored ship is the positioning error of the ship-borne GPS equipment.

[0022] Furthermore, the impact of main engine starting performance on ship maneuverability includes:

[0023] The calculation formula for the time required for the main engine to start and the distance from the main engine starting to the ship obtaining sufficient power is as follows:

[0024]

[0025]

[0026] Among them, T s Indicates the host startup time, S s Main engine starting inertia distance, Δ is the ship displacement tonnage, V o is the ground speed, R o R is the speed required to offset the external resistance of the hull. o is an empirical constant of 9.8 kn.

[0027] Furthermore, the impact of restricted waterways on ship maneuverability includes:

[0028] The impact of restricted waters on the maneuverability of anchored vessels is five times the draft of the vessel;

[0029] The calculation formula for ship displacement tonnage Δ is as follows:

[0030] Δ=c b LbD m ;

[0031] Among them, c b represents the coefficient, obtained from the structural parameters of the ship, L is the total length, B is the width, d m Indicates the draft of the middle part of the ship.

[0032] Furthermore, it also includes: comparing the safety perception turning radius of the anchored ship obtained by constructing the model with the turning radius actually measured by ArcGIS and AIS system to verify the effectiveness of the model.

[0033] Furthermore, the calculation formula of the safe perception turning radius R of the anchored ship is as follows:

[0034] R=R a +L0+2r+ΔR;

[0035] ΔR=S s +5d m ;

[0036] Among them, R a is the horizontal projection length of the anchor chain, L o is the total length of the anchor chain, r represents the positioning error of the equipment, ΔR represents the impact distance of the starting performance and restricted waters on the sensing radius, S s The inertia distance of the host startup, d m Indicates the draft of the middle part of the ship.

[0037] The present invention also provides a dynamic safety warning system for an anchored ship, comprising:

[0038] Data acquisition module, which obtains AIS static and dynamic data information of ports including anchored ships;

[0039] The data processing module records the navigation status of the ship according to the AIS, filters the information of the anchored ship in the specific port waters, and obtains the ship model and size information of the anchored ship; according to the nautical chart information of the port waters, filters the data information of the topography and external environmental conditions of the anchored waters of the port; calculates the anchor chain length, the positioning error of the anchored ship, the positioning error of the anchor position, the water depth of the anchorage, the ship size, the main engine starting performance and the influence of the restricted waterway on the ship's maneuverability based on the ship model and size information of the anchored ship, the topography and external environmental conditions of the anchored waters;

[0040] The model building module is based on the influence of anchor chain length, anchored ship positioning error, anchor position positioning error, anchorage water depth, ship size, main engine starting performance and restricted waterway on ship maneuverability to obtain the safe perception turning radius of the anchored ship;

[0041] The safety warning module provides dynamic safety warning for the anchored ship based on the safety perception turning radius of the anchored ship.

[0042] Furthermore, it also includes: a model verification module, which verifies the validity of the model by comparing the safety perception turning radius of the anchored ship obtained by the model construction module based on the turning radius actually measured by ArcGIS and the AIS system.

[0043] Advantages and positive effects of the present invention:

[0044] Existing research on the identification and early warning of potential risks of ships has mostly focused on ships at sea. However, for anchored ships, as a special type of unpowered ship, considering the complexity of the external environment of the anchoring waters and the effect of the ship's inertia, the potential collision risk is greater than that of ships at sea. Therefore, the present invention considers multiple factors such as ship size, the impact of the external natural environment, the error of the ship-borne positioning system, the start-up performance of the ship's main engine, and the influence of maneuvering in restricted waters, and proposes a new anchored ship safety warning perception area model method and system. The dynamic and static information of the anchored ship itself is fully taken into account, and the potential complex related variables inside and outside the anchored ship, such as the positioning error of the anchored ship, the positioning error of the anchor position, the water depth of the anchorage, the size of the ship, the start-up performance of the main engine, and the influence of restricted waterways on the maneuverability of the ship, are accumulated and calculated to build a safety warning perception area model for anchored ships.

[0045] In the forecast model of the present invention, the radius of the anchored ship safety warning perception area is calculated. When selecting the anchorage, terrain and seabed quality, factors such as water depth, shelter from the wind and leeward should be considered to ensure the safety of the anchored ship itself. Generally speaking, marine pilots need to determine the exact position of the ship during anchoring operations; however, due to human errors and electronic instrument errors and other influencing factors, positioning errors cannot be ignored when determining the exact ship position and anchor position. The ship-borne GPS global positioning system is used to provide accurate positioning when the ship is anchored, and accurately calculates the cumulative GPS positioning error and the safe turning radius of the anchored ship taking into account the ship's own size; when the anchored ship is in imminent danger of collision and needs to avoid immediately, the starting performance and maneuverability in restricted waters will have a significant impact on the pilot's operation. In order to establish a more realistic and accurate risk perception and early warning model, the dynamic early warning perception mooring model cumulatively calculates the starting performance of the ship's engine main engine and the potential impact of ship maneuvering in restricted waters; the model verification module verifies the effectiveness of the model by comparing the safe turning radius of the anchored ship calculated by the new dynamic anchored ship safety early warning perception model based on the turning radius measured by ArcGIS and AIS system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0047] Figure 1 The risk perception model area considering the captain in the embodiment of the present invention;

[0048] Figure 2 It is a risk perception model area considering the shipborne GPS positioning error in the embodiment of the present invention;

[0049] Figure 3 It is a risk perception model area that comprehensively considers the impact of dynamic and static factors of the ship in the embodiment of the present invention;

[0050] Figure 4 is the motion trajectory of a ship anchored at a specific anchorage in an embodiment of the present invention;

[0051] Figure 5 is the turning radius of the dynamic perception model for safety early warning of anchored ships in an embodiment of the present invention;

[0052] Figure 6 The calculated risk perception radius in the embodiment of the present invention is compared with the measured radius. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0055] Real-time shipborne automatic identification equipment AIS data records can provide measured dynamic and static information for water transportation vehicles and platform equipment, such as ship route estimation, marine traffic distribution anomaly detection, ship collision risk prediction and path safety planning. By identifying and perceiving the accident risks in anchorage waters, ship operators and maritime supervision organizations can better grasp the real-time traffic flow status when monitoring real-time water traffic in anchorages, thereby improving the safety of ships in coastal waterways. Therefore, in order to accurately perceive and identify collision risks and reduce marine accidents in restricted anchorage waters, considering the length of anchor chain, anchorage water depth, ship type, ship positioning accuracy, ship main engine startup performance and the impact of restricted waters on ship maneuverability, this paper proposes a new risk perception and warning method based on AIS trajectory records-safety warning dynamic perception model. Taking a specific port anchorage as a research case, the real anchored ship data extracted from the AIS record is selected to verify the effectiveness and practicality of the proposed perception model.

[0056] like Figure 1-6 As shown, a method for dynamic perception of safety warning of an anchored ship in an embodiment of the present invention includes the following steps:

[0057] S1. Calculate the mooring turning radius of the anchored ship, and calculate the cumulative sum of the horizontal projection length of the hanging chain and the length of the flat chain according to the length of the anchor chain of the anchored ship;

[0058] Based on the external ocean meteorological conditions, anchor penetration usually requires releasing a sufficient length of anchor chain to ensure that the ship obtains sufficient seabed grip after dropping anchor; at the same time, the anchored ship is affected by the external wind and wave currents and will perform a gyratory motion with a certain gyratory circle radius with the anchoring coordinates as the center.

[0059] In the specific implementation, S1 specifically includes:

[0060] S11. According to the action of the anchor chain thrown by the anchored vessel, the anchor chain is generally divided into a hanging chain part and a flat chain part;

[0061] S12. Calculate the horizontal projection length of the hanging chain part;

[0062] S13. To ensure that the anchor chain of the moored ship is of sufficient length and sufficient anchor holding force is obtained, calculate the total length of the anchor chain.

[0063] The calculation formula of the suspension chain length is as follows:

[0064]

[0065] Where T o represents the horizontal external force acting on the hull, w c Indicates the weight of the anchor chain per unit length in water. L c It represents the length of the catenary part, and H represents the length from the anchor hole to the seabed.

[0066] The formula for calculating the length of the tile chain is as follows:

[0067]

[0068] L h Indicates the length of the flat anchor chain, w a represents the weight of the anchor chain per unit length in the air, η a and η c They represent the holding coefficient of the anchor and the holding coefficient of the anchor chain respectively.

[0069] The total length L of the chain is calculated as follows:

[0070]

[0071] According to the empirical formula of the anchor chain length:

[0072] L=3H0+90wind velocity≈20m / s(BF8) (4)

[0073] L=4H0+145wind velocity≈20m / s(BF11) (5)

[0074] Among them, H o It indicates the water depth at anchorage, and BF is the Beaufort wind scale.

[0075] S2. Calculate the positioning error of the shipborne GPS equipment, and calculate the safe turning radius of the anchored ship taking into account the cumulative positioning error and the anchor chain length of the single anchor anchoring ship;

[0076] The maritime navigator needs to determine the exact position of the ship during the anchoring operation; due to human errors, electronic instrument errors and other influencing factors, when determining the exact ship position and anchor position, the ship-borne GPS global positioning system is used to provide accurate positioning when the ship is anchored, accurately calculate the cumulative GPS positioning error and the safe turning radius of the anchored ship taking into account the ship's own size; the positioning accuracy of marine GPS and DGPS can be accurate to about 0 to 10 meters. On the basis of fully considering the influence of various factors such as instrument and human intervention errors, the present invention proposes to select a dynamic perception warning model of 10 meters as the radius of the circle for positioning error estimation; that is, the value of r is 10m. In addition, in order to fully ensure the safety of anchored ships, the model takes into account both anchor positioning and ship positioning errors.

[0077] S3. According to different ship main engine types, determine and calculate the contribution of the main engine startup performance considering the ship size to the safe perceived turning radius of the anchored ship; determine and calculate the contribution of the factors of maneuvering restricted anchoring waters to the safe perceived turning radius of the anchored ship;

[0078] The calculation of the safe turning radius of an anchored ship takes into account the starting performance of the main engine of the anchored ship and the factors of maneuvering in restricted anchoring waters. When the anchored ship is in imminent danger of collision and needs to avoid it immediately, the starting performance and maneuverability in restricted waters will have a significant impact on the pilot's operation; the dynamic warning perception anchoring model accumulates the starting performance of the ship's main engine and the potential ship maneuvering impact in restricted waters;

[0079] The calculation formulas for the time required for the main engine to start and the distance from the main engine starting to the ship obtaining sufficient power are as follows:

[0080]

[0081] Among them, T s Indicates the host startup time, S s Main engine starting inertia distance, Δ is the ship displacement tonnage, V o is the ground speed, R o R is the speed required to offset the external resistance of the hull. o is an empirical constant of 9.8 kn.

[0082] The calculation formula for ship displacement tonnage Δ is as follows:

[0083] Δ=c b LbD m (8)

[0084] or

[0085] Δ=DWη dw (9)

[0086] Among them, C b represents the coefficient, which can be obtained from the structural parameters of the ship, L is the total length, B is the width, d m Indicates the draft depth of the middle part of the ship. DW is the designed deadweight tonnage, η dw is the design deadweight tonnage factor.

[0087] Table 1 Reference values ​​of design deadweight tonnage coefficient

[0088]

[0089] Restricted waterways refer to restricted waterways such as rivers, canals, coastal ports and anchorages, where the maneuverability of ships is severely affected and restricted. These restricted areas further complicate the maneuverability and self-control performance of complex and heavy maritime traffic flows. According to statistical research, considering the difference between the motion state of anchored ships and ships under sail, the impact of restricted waters on the maneuverability of anchored ships may be about 5 times the draft of the ship. Verification based on AIS measured records shows that this estimate is feasible.

[0090] Taking into account the length of the ship's anchor chain, GPS positioning error, the ship's main engine startup performance and the factors affecting the ship's maneuverability in restricted waters, the calculation formula for the radius R of the new anchored ship's safety perception warning area is as follows:

[0091] R=R a +L0+2r+ΔR (10)

[0092] ΔR=S s +5d m (11)

[0093] Among them, R a is the horizontal projection length of the anchor chain, L o is the total length of the anchor chain, r represents the positioning error of the equipment, ΔR represents the impact distance of the starting performance and restricted waters on the sensing radius, S s The inertia distance of the host startup, d m Indicates the draft of the middle part of the ship.

[0094] S4. The actual ship automatic identification system AIS is used to record the dynamic and static data of real anchored ships to verify the effectiveness of the created anchored ship safety awareness and warning model.

[0095] In the specific implementation, ArcGIS software is used to obtain massive AIS static and dynamic data information of specific ports, including anchored ships.

[0096] In specific implementation, S4 includes:

[0097] S41. ArcGIS is used to extract the dynamic spatiotemporal distribution data of ships in specific port waters, and further screen out the data information for selecting anchored ships.

[0098] S42. Dynamic information of ships in the extracted AIS data: real-time position (longitude and latitude), ground course (COG), ground speed (SOG), MMSI (Maritime Mobile Service Identity), rate of turn (ROT), heading, voyage identification number, etc. Further obtain static information of voyages and ships, such as ship width, length, draft, ship type and voyage destination. Thousands of AIS records were extracted for mining and analysis of anchored ships, including about hundreds of anchored ship record information. Data quality screening was performed, and only valid and complete AIS records were retained for further model verification experiments based on ArcGIS software. Ship records that were sailing or moored, special missions that may not comply with navigation rules, such as tugboats, refueling ships and police patrols, and ships without MMSI numbers, such as yachts and fishing boats, were not included. In addition, only by adopting a complete swing area / circling area can the risk perception warning model be accurately and comprehensively verified. Therefore, a total of 33 ships with complete motion trajectories were screened out in the experiment.

[0099] S43. Select and visualize the nautical chart information of the port waters, and mark the anchoring water area of ​​the port waters in detail.

[0100] S44, according to the established radius model of the anchored ship safety warning turning waters, combined with the extracted static and dynamic real data information of the anchored ship, the turning radius of the warning model of the anchored ship is calculated.

[0101] S45. Compare the safe turning radius of the anchored ship calculated by the new dynamic anchored ship safety warning perception model with the turning radius measured by ArcGIS and AIS system to verify the effectiveness of the model.

[0102] In the above embodiments, the present invention establishes a safety perception warning method and system for anchored ships. When selecting anchorages, terrain and seabed quality, anchored ships should fully consider factors such as water depth, shelter from wind, and leeward to ensure the safety of the anchored ship itself. Usually, marine pilots need to determine the exact position of the ship during anchoring operations; however, due to human errors and electronic instrument errors and other influencing factors, positioning errors cannot be ignored when determining the exact position of the ship and anchor position. The shipborne GPS global positioning system is used to provide accurate positioning when the ship is anchored. The present invention accurately calculates the cumulative GPS positioning error and the accumulation of the safe turning radius of the anchored ship taking into account the ship's own size; in addition, when the anchored ship is in imminent danger of collision and needs to avoid immediately, the starting performance and maneuverability in restricted waters will have a significant impact on the pilot's operation. In order to establish a more realistic and accurate risk perception and early warning model, the present invention uses a dynamic early warning perception anchoring model that accumulates the starting performance of the ship's engine main engine and the potential ship maneuvering impact in restricted waters; existing research on ship potential risk identification and early warning focuses on ships at sea, but for anchored ships as a special type of unpowered ship, considering the complexity of the external environment of its anchoring waters and the effect of ship inertia, the potential collision risk is greater than that of ships at sea. Therefore, the present invention considers multiple factors such as ship size, external natural environment impact, error of ship-borne positioning system, ship main engine starting performance, and restricted waters maneuvering impact, and proposes a new anchored ship safety early warning perception area model method and system. The dynamic and static information of the anchored ship itself is fully taken into account, and the internal and external potential complex related variables of the anchored ship such as positioning error of the anchored ship, anchor position positioning error, anchorage water depth, ship size, positioning accuracy, main engine starting performance, and the impact of restricted waterways on the ship's maneuverability are accumulated and calculated to establish a model. The turning radius measured by ArcGIS and AIS system was compared with the safe turning radius of anchored ships calculated by the new dynamic anchored ship safety warning perception model to verify the effectiveness of the model.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic safety early warning method for an anchored ship, characterized in that: The following steps are involved: Obtain AIS static and dynamic data information of ports including anchored ships; According to the navigation status of the ship recorded by AIS, the information of anchored ships in specific port waters is screened, and the ship model and size information of the anchored ships is obtained; according to the nautical chart information of the port waters, the data information of the topography and external environmental conditions of the anchored waters of the port is screened; Calculate the anchor chain length, anchor ship positioning error, anchor position positioning error, anchorage depth, ship size, main engine starting performance and the impact of restricted waterways on ship maneuverability based on the ship model, size information, anchored ship anchoring waters terrain and external environmental conditions data; Based on the influence of anchor chain length, anchored ship positioning error, anchor position positioning error, anchorage water depth, ship size, main engine starting performance and restricted waterway on ship maneuverability, the safe perception turning radius of anchored ship is obtained; Dynamic safety warning of anchored ships is carried out based on the safety perception turning radius of anchored ships.

2. A dynamic safety early warning method for an anchored ship according to claim 1, characterized in that: Calculate the anchor chain length, including: Establish an accurate calculation model for the anchor chain length of a single-anchor ship; divide the anchor chain length of the anchored ship into a suspended anchor chain part suspended in the water and a flat anchor chain part on the seabed that provides additional grip; calculate the horizontal projection anchor chain length of the suspended anchor chain part. The anchor chain length of a single-anchor ship is equal to the horizontal projection of the suspended chain plus the length of the flat anchor chain on the seabed; The calculation formula of the suspension chain length is as follows: The formula for calculating the length of the tile chain is as follows: The total length L of the chain is calculated as follows: Among them, T o represents the horizontal external force acting on the hull, w c Indicates the weight of the anchor chain per unit length in water; L c represents the length of the catenary part, and H represents the length from the anchor hole to the seabed; where L h Indicates the length of the flat anchor chain, w a represents the weight of the anchor chain per unit length in the air, η a and η c They represent the holding coefficient of the anchor and the holding coefficient of the anchor chain respectively.

3. A dynamic safety early warning method for an anchored ship according to claim 1, characterized in that: The positioning error of an anchored ship is the positioning error of the ship-borne GPS equipment.

4. A dynamic safety early warning method for an anchored ship according to claim 1, characterized in that: The impact of main engine starting performance on ship maneuverability includes: The calculation formula for the time required for the main engine to start and the distance from the main engine starting to the ship obtaining sufficient power is as follows: Among them, T s Indicates the host startup time, S s Main engine starting inertia distance, Δ is the ship displacement tonnage, V o is the ground speed, R o R is the speed required to offset the external resistance of the hull. o is an empirical constant of 9.8 kn.

5. A dynamic safety early warning method for an anchored ship according to claim 1, characterized in that: The impact of restricted waterways on ship maneuverability, including: The impact of restricted waters on the maneuverability of anchored vessels is five times the draft of the vessel; The calculation formula of ship displacement tonnage Δ is as follows: Δ=c b LBd m ; Among them, c b represents the coefficient, obtained from the structural parameters of the ship, L is the total length, B is the width, d m Indicates the draft of the middle part of the ship.

6. A dynamic safety early warning method for an anchored ship according to claim 1, characterized in that: Also includes: The turning radius measured by ArcGIS and AIS system is compared with the safety perception turning radius of anchored ships constructed by the model to verify the effectiveness of the model.

7. A dynamic safety early warning method for an anchored ship according to claim 1, characterized in that: The calculation formula of the safe perceived turning radius R of an anchored ship is as follows: R=R a +L0+2r+ΔR; ΔR=S s +5d m ; Among them, R a is the horizontal projection length of the anchor chain, L o is the total length of the anchor chain, r represents the positioning error of the equipment, ΔR represents the impact distance of the starting performance and restricted waters on the sensing radius, S s The inertia distance of the host startup, d m Indicates the draft of the middle part of the ship.

8. A dynamic safety warning system for an anchored ship, characterized in that: include: Data acquisition module, which obtains AIS static and dynamic data information of ports including anchored ships; The data processing module records the navigation status of the ship according to the AIS, filters the information of the anchored ship in the specific port waters, and obtains the ship model and size information of the anchored ship; according to the nautical chart information of the port waters, filters the data information of the topography and external environmental conditions of the anchored waters of the port; calculates the anchor chain length, the positioning error of the anchored ship, the positioning error of the anchor position, the water depth of the anchorage, the ship size, the main engine starting performance and the influence of the restricted waterway on the ship's maneuverability based on the ship model and size information of the anchored ship, the topography and external environmental conditions of the anchored waters; The model building module is based on the influence of anchor chain length, anchored ship positioning error, anchor position positioning error, anchorage water depth, ship size, main engine starting performance and restricted waterway on ship maneuverability to obtain the safe perception turning radius of the anchored ship; The safety warning module provides dynamic safety warning for the anchored ship based on the safety perception turning radius of the anchored ship.

9. A dynamic safety warning system for an anchored vessel according to claim 8, characterized in that: It also includes: a model verification module, which verifies the validity of the model by comparing the safety perception turning radius of the anchored ship obtained by the model construction module based on the turning radius measured by ArcGIS and the AIS system.

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