Ship encounter space-time danger degree evaluation method and system considering influence of navigation environment

Abstract

The application relates to a ship encounter space-time danger degree evaluation method and system considering the influence of a navigation environment, and belongs to the technical field of ship safe driving. The application is aimed at solving the problem that the action time of collision avoidance in a complex sea environment cannot be accurately determined. A ship environment sensing module and a positioning module are used to obtain channel environment information of a ship navigation area and ship position, heading and speed information; the closest encounter distance of two ships, the encounter time of the ship from the current position to the closest intersection point of the two ships, the safe encounter distance of the two ships, the absolute safe encounter distance, the latest avoidance distance and the distance that can be avoided by taking measures are calculated; the collision danger degree in the space position and the collision danger degree of the two ships in the time dimension are further calculated; the space danger degree and the time danger degree are combined by using a synthesis operator to solve the space-time collision danger degree; and the danger degree of ship collision is evaluated according to the danger degree. The application is suitable for ship encounter space-time danger degree evaluation.

Description

Technical Field

[0001] The invention belongs to the technical field of safe ship driving. Background Art

[0002] Despite the continuous improvement of navigational instruments and equipment for safe navigation, and the advancement of collision avoidance technologies, including the International Maritime Organization's resolution mandating the installation of automatic identification systems (AIS) on ships, ship collisions remain a persistent problem. These devices allow ships to accurately obtain their own position, heading, and speed, and easily obtain information about other ships. However, due to the impact of terrain structure, the dynamic characteristics of ships, and inclement weather conditions that can affect maritime traffic, the timing of collision avoidance maneuvers during navigation still largely depends on the subjective judgment of the pilot, posing significant collision risks and potential safety hazards.

[0003] The paper "Calculation of Ship Composite Collision Risk Based on Fuzzy Theory" proposes a method for calculating the composite collision risk of ships. This algorithm is based on the concepts of ship domain and dynamic domain. On the basis of the ship collision geometry principle, it uses fuzzy rules and fuzzy comprehensive evaluation methods to judge the ship collision risk. However, this method does not consider the timing of the action that the ship should take when the risk changes.

[0004] The paper "Ship Collision Avoidance Integrated Decision-Making System" studies ship collision avoidance behavior and the thought process behind multi-ship, multi-criteria collision avoidance decisions. Applying maritime traffic engineering theory and fuzzy set theory, it establishes a multi-object, multi-criteria ship collision avoidance integrated decision-making model. However, this algorithm fails to consider the impact of navigable area size and weather changes on ship collision avoidance decisions.

[0005] The paper "Construction of a Ship Collision Risk Model" establishes a mathematical model for determining the risk of collision between ships based on the concept of "domain" and fuzzy principles. This model not only comprehensively considers the impact of multiple factors on collision risk but is also simple and easy to implement. However, this method also fails to consider the impact of collision risk on the timing of collision avoidance actions.

[0006] Some of the above literature does not consider the impact of the collision risk on the timing of collision avoidance maneuvers. Some also fail to consider the impact of weather factors and the size of the navigable area on collision risk. However, in actual navigation, ships often face more complex and dangerous collision avoidance scenarios. Various factors affect the collision risk of ships and interfere with the pilot's judgment on the timing of collision avoidance maneuvers. This results in an unclear timing for collision avoidance maneuvers. Summary of the Invention

[0007] The present invention aims to solve the problem that the timing of collision avoidance actions cannot be accurately determined in collision avoidance scenarios in complex marine environments. A method and system for assessing the temporal and spatial risk of ship encounters taking into account the influence of the navigation environment are provided.

[0008] The method for assessing the temporal and spatial risk of a ship encountering a vessel considering the influence of the navigation environment of the present invention comprises:

[0009] Step 1: Obtain the channel environment information of the ship's navigation area and the ship's own position, heading and speed information through the ship environment perception module and positioning module;

[0010] Step 2: Calculate the closest approach distance DCPA and the approach time TCPA from the current position of the ship to the closest point of intersection based on the channel environment information within the navigable area and the ship's own position, heading, and speed information;

[0011] Based on the channel environment information within the navigable area and the ship's own position, heading and speed information, the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1 and the avoidance distance D2 where measures can be taken are calculated.

[0012] Step 3: Using the distance and time calculated in step 2, calculate the collision risk level SCRI in spatial position and the collision risk level TCRI of the two ships in the time dimension;

[0013] Step 4: Use the synthesis operator to combine the spatial risk index SCRI and the temporal risk index TCRI to calculate the spatiotemporal collision risk index STCRI.

[0014] Step 5: Evaluate the risk of ship collision based on the spatial risk index (SCRI), temporal risk index (TCRI) and spatiotemporal collision risk index (STCRI).

[0015] Furthermore, in the present invention, in step one, the waterway environment information includes the position, course, speed, range of the navigable area and weather condition information of the navigable vessels around the ship.

[0016] The scope of the navigable area includes the width of the river, the width of the port, etc.

[0017] Furthermore, in the present invention, in step 2, the closest approach distance DCPA of the two ships is:

[0018]

[0019] Among them, V0 is the speed of the ship; V t For the speed of his ship; is the heading angle of own ship; is the heading angle of the other ship; θ is the azimuth of the other ship relative to the own ship; r is the relative distance between the other ship and the own ship.

[0020] Furthermore, in the present invention, in step 2, the encounter time TCPA of the ship from the current position to the closest intersection point of the two ships is:

[0021]

[0022] Furthermore, in the present invention, in step 2, the safe encounter distance d1 and the absolutely safe encounter distance d2 of the two ships are respectively:

[0023]

[0024] d2=K1·d1

[0025] Where W is the channel width; D is the ship width; E is the current visibility; L is the ship length; R is the distance between the two ships; V r It is the relative speed of the two ships in the encounter. K1 represents the distance expansion coefficient caused by the influence of harsh environment. It is determined by factors such as the instability of the ship status, the uncoordinated actions of the two ships and the error of the equipment. The value range is 3 to 5.

[0026] Furthermore, in the present invention, in step 2, the latest avoidance distance D1 and the avoidance distance D2 that can be avoided are:

[0027]

[0028] D2=K2·D1

[0029] Furthermore, in the present invention, in step 3, the collision risk level SCRI at the spatial position is:

[0030]

[0031] Furthermore, in the present invention, in step 3, the collision risk level TCRI of the two ships in the time dimension is:

[0032]

[0033] Furthermore, in the present invention, in step 4, the spatiotemporal collision risk STCRI is:

[0034]

[0035] Where, is a composite operator, and the specific composite rules are:

[0036] (1) If SCRI is 0, then STCRI is 0;

[0037] (2) If SCRI is not 0 and TCRI is 0, then STCRI is 0;

[0038] (3) If both SCRI and TCRI are not 0, then STCRI is the larger value of SCRI and TCRI.

[0039] Furthermore, in the present invention, in step 5, the method for evaluating the risk of ship collision is:

[0040] When SCRI = 0, there is no risk of collision between the two ships;

[0041] When SCRI>0 and STCRI=0, the risk of collision between the two ships begins to arise; the give-way vessel needs to take collision avoidance action according to the International Regulations for Preventing Collisions at Sea;

[0042] When STCRI>0, the collision risk is increasing. The give-way vessel still needs to take action to avoid collision, while the direct-traveling vessel is allowed to take collision avoidance action to avoid collision.

[0043] When STCRI=0 or the rate of change of TCRA is greater than 0, the collision avoidance risk gradually decreases.

[0044] A ship encounter spatiotemporal risk assessment system considering the impact of the navigation environment, including a data acquisition module, an encounter collision parameter calculation module, a collision risk calculation module, and a ship collision risk assessment module;

[0045] The data acquisition module is used to obtain the channel environment information of the ship's navigation area and the ship's own position, heading and speed information through the ship environment perception module and positioning module;

[0046] The encounter and collision parameter calculation module is used to calculate the closest encounter distance DCPA of the two ships and the encounter time TCPA from the current position of the ship to the closest intersection point of the two ships based on the channel environment information in the navigable area and the ship's own position, heading and speed information;

[0047] The collision parameter calculation module is also used to calculate the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1 and the avoidance distance D2 that can be avoided based on the channel environment information in the navigable area and the ship's own position, heading and speed information;

[0048] The collision risk calculation module is used to calculate the collision risk level SCRI in the spatial position and the collision risk level TCRI of the two ships in the time dimension using the distance and time calculated in steps 2 and 3;

[0049] The ship collision risk assessment module is used to assess the risk of ship collision based on the spatial risk index SCRI, temporal risk index TCRI and spatiotemporal collision risk index STCRI.

[0050] The method and system are used in actual navigation process, and a ship faces more complex and dangerous collision avoidance scenes, although the COLREGs rules stipulate basic ship collision avoidance requirements and specifications, but still do not make clear statements on when the collision risk occurs, and when the encountered ship takes collision avoidance and homing actions, the safe encounter distance, the latest collision avoidance distance and the synthesis operator are designed, more accurate space-time collision risk is calculated, and the action to be taken by the ship is judged according to the size and change law, the problems of inaccurate collision risk and unclear collision avoidance behavior in the collision avoidance process are solved, and the collision avoidance efficiency and navigation safety of the ship in the navigation process are improved. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a flowchart of the method of the present application;

[0052] Figure 2 is a principle diagram of the minimum encounter distance and the minimum encounter time of the ship;

[0053] Figure 3 is a schematic diagram of the safe encounter distance, the absolute safe encounter distance, the latest avoidance distance and the avoidable measure avoidance distance of the ship;

[0054] Figure 4 is a system diagram of the present application. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0056] Specific implementation one: refer to the drawings Figures 1 to 3 Specifically, the ship encounter space-time risk assessment method considering the influence of navigation environment in the embodiment includes:

[0057] Step one, through the ship environment perception module and the positioning module, the channel environment information of the ship navigation area and the ship's own position, heading and speed information are obtained;

[0058] Step two, according to the channel environment information in the navigable area and the ship's own position, heading and speed information, the closest approach distance DCPA of two ships and the encounter time TCPA of the ship from the current position to the closest approach point of two ships are calculated;

[0059] Based on the channel environment information within the navigable area and the ship's own position, heading and speed information, the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1 and the avoidance distance D2 where measures can be taken are calculated.

[0060] Step 3: Using the distance and time calculated in step 2, calculate the collision risk level SCRI in spatial position and the collision risk level TCRI of the two ships in the time dimension;

[0061] Step 4: Use the synthesis operator to combine the spatial risk index SCRI and the temporal risk index TCRI to calculate the spatiotemporal collision risk index STCRI.

[0062] Step 5: Evaluate the risk of ship collision based on the spatial risk index (SCRI), temporal risk index (TCRI) and spatiotemporal collision risk index (STCRI).

[0063] Furthermore, in the present invention, in step one, the waterway environment information includes the position, course, speed, range of the navigable area and weather condition information of the navigable vessels around the ship.

[0064] The scope of the navigable area includes the width of the river, the width of the port, etc.

[0065] Furthermore, in the present invention, in step 2, the closest approach distance DCPA of the two ships is:

[0066]

[0067] Among them, V0 is the speed of the ship; V t For the speed of his ship; is the heading angle of own ship; is the heading angle of the other ship; θ is the azimuth of the other ship relative to the own ship; r is the relative distance between the other ship and the own ship.

[0068] Furthermore, in the present invention, in step 2, the encounter time TCPA of the ship from the current position to the closest intersection point of the two ships is:

[0069]

[0070] Furthermore, in the present invention, in step 2, the safe encounter distance d1 and the absolutely safe encounter distance d2 of the two ships are respectively:

[0071]

[0072] d2=K1·d1

[0073] Where W is the channel width; D is the ship width; E is the current visibility; L is the ship length; R is the distance between the two ships; V rIt is the relative speed of the two ships in the encounter. K1 represents the distance expansion coefficient caused by the influence of harsh environment. It is determined by factors such as the instability of the ship status, the uncoordinated actions of the two ships and the error of the equipment. The value range is 3 to 5.

[0074] Furthermore, in the present invention, in step 2, the latest avoidance distance D1 and the avoidance distance D2 that can be avoided are:

[0075]

[0076] D2=K2·D1

[0077] Furthermore, in the present invention, in step 3, the collision risk level SCRI at the spatial position is:

[0078]

[0079] Furthermore, in the present invention, in step 3, the collision risk level TCRI of the two ships in the time dimension is:

[0080]

[0081] Furthermore, in the present invention, in step 4, the spatiotemporal collision risk STCRI is:

[0082]

[0083] Where, is a composite operator, and the specific composite rules are:

[0084] (1) If SCRI is 0, then STCRI is 0;

[0085] (2) If SCRI is not 0 and TCRI is 0, then STCRI is 0;

[0086] (3) If both SCRI and TCRI are not 0, then STCRI is the larger value of SCRI and TCRI.

[0087] Furthermore, in the present invention, in step 5, the method for evaluating the risk of ship collision is:

[0088] When SCRI = 0, there is no risk of collision between the two ships;

[0089] When SCRI>0 and STCRI=0, the risk of collision between the two ships begins to arise; the give-way vessel needs to take collision avoidance action according to the International Regulations for Preventing Collisions at Sea;

[0090] When STCRI>0, the collision risk is increasing. The give-way vessel still needs to take action to avoid collision, while the direct-traveling vessel is allowed to take collision avoidance action to avoid collision.

[0091] When STCRI=0 or the rate of change of TCRA is greater than 0, the collision avoidance risk gradually decreases.

[0092] A ship encounter spatiotemporal risk assessment system considering the influence of the navigation environment comprises a data acquisition module (1), an encounter collision parameter calculation module (2), a collision risk calculation module (3), and a ship collision risk assessment module (4);

[0093] The data acquisition module (1) is used to obtain the channel environment information of the ship's navigation area and the ship's own position, heading and speed information through the ship environment perception module and the positioning module;

[0094] The encounter and collision parameter calculation module (2) is used to calculate the closest encounter distance DCPA of the two ships and the encounter time TCPA from the current position of the ship to the closest intersection point of the two ships based on the channel environment information in the navigable area and the position, heading and speed information of the ship itself;

[0095] The collision parameter calculation module is also used to calculate the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1 and the avoidance distance D2 that can be avoided based on the channel environment information in the navigable area and the ship's own position, heading and speed information;

[0096] The collision risk calculation module (3) is used to calculate the collision risk level SCRI in the spatial position and the collision risk level TCRI of the two ships in the time dimension using the distance and time calculated in step 2 and step 3;

[0097] The ship collision risk assessment module (4) is used to assess the risk of ship collision based on the spatial risk index SCRI, the temporal risk index TCRI and the spatiotemporal collision risk index STCRI.

[0098] Specific real-time processes for risk avoidance include:

[0099] 1. Obtaining the waterway environment information of the ship's navigation area and its own position, heading, and speed information. The ship is equipped with marine environment perception modules such as a navigation radar system, a satellite positioning navigation system, an AIS ship automatic identification system, a laser radar, and a binocular vision system, which can obtain the waterway environment information around the ship and its own position, heading, and speed information in real time;

[0100] The above-mentioned channel environment information refers to the position, course, speed information of other navigable ships around the ship, the range information of the navigable area and weather conditions information.

[0101] 2. Calculate the closest approach distance DCPA and the closest approach time TCPA from the current position of the ship to the intersection point of the two ships.

[0102]

[0103]

[0104] Among them, V0 is the speed of the ship; V t For the speed of his ship; is the heading angle of own ship; is the heading angle of the other ship; θ is the azimuth of the other ship relative to the own ship; r is the relative distance between the other ship and the own ship.

[0105] 3. Calculate the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1, and the avoidance distance D2 where measures can be taken.

[0106]

[0107] d2=K1·d1

[0108]

[0109] D2=K2·D1

[0110] Where W is the channel width; D is the ship width; E is the current visibility; L is the ship length; R is the distance between the two ships; V r is the relative speed of the two encountering ships, and V is the own ship's speed. K1 and K2 represent the distance expansion coefficients caused by adverse environmental conditions. These coefficients are determined by factors such as ship instability, uncoordinated actions between the two ships, and equipment errors, and are generally set between 3 and 5.

[0111] 4. Calculate the collision risk level SCRI of the two ships in spatial position and the collision risk level TCRI of the two ships in time dimension.

[0112] SCRI represents the degree of danger of the two ships in space, and its mathematical expression is:

[0113]

[0114] Where d1 is the safe encounter distance of ships, and d2 is the absolutely safe encounter distance.

[0115] TCRI represents the degree of danger between two ships in the time dimension, and its mathematical expression is:

[0116]

[0117] Where V r is the relative speed of the other ship to our ship, D1 is the latest avoidance distance, and D2 is the distance at which avoidance measures can be taken.

[0118] 5. A synthetic operator is designed to combine the spatial risk SCRi and the temporal risk TCRi to calculate the spatio-temporal collision risk STCRi.

[0119] The spatio-temporal collision risk STCRi can be obtained by combining the SCRi and the TCRi, and the combination method is as follows:

[0120]

[0121] In the formula, is a synthetic operator, and the specific synthesis rule is as follows:

[0122] (1) If SCRi is 0, then STCRi is 0;

[0123] (2) If SCRi is not 0 and TCRi is 0, then STCRi is 0;

[0124] (3) If SCRi and TCRi are both not 0, then STCRi is the larger one of SCRi and TCRi.

[0125] 6. According to the calculated spatial risk SCRi, temporal risk TCRi and spatio-temporal collision risk STCRi, it is determined what action should be taken in the ship encounter situation.

[0126] When SCRi = 0, there is no collision risk between the two ships, and each ship is free to take action.

[0127] When SCRi > 0 and STCRi = 0, the collision risk begins to occur, and the giving-way ship should take action to avoid collision according to the COLREGs rules.

[0128] When STCRi > 0, the collision risk is large, and the giving-way ship should still take action to avoid collision, but the oncoming ship is allowed to take action to avoid collision.

[0129] When STCRi = 0 or the rate of change of TCRi is greater than 0, the collision risk gradually disappears, and the homing action can be performed.

[0130] A spatio-temporal risk judgment method for a ship encounter situation,

[0131] The system comprises:

[0132] (1) An information data processing module: transmitting the channel environment information of the ship navigation sea area, accepting the task information, and processing and optimizing various data, updating the channel environment information at regular intervals, providing the time-varying channel environment information and the current position, speed and heading information of the ship for the collision risk assessment module.

[0133] The above-mentioned channel environment information refers to the position, speed and course information of other navigable vessels around the ship and the range information of the navigable area.

[0134] (2) Collision risk assessment module: Based on the received mission instructions and the current status information of the own ship, the status information of other ships, and the weather and channel information, the closest approach distance DCPA and the closest approach time TCPA are calculated to generate the spatial risk index SCRI and the temporal risk index TCRI. The spatiotemporal collision risk index STCRI is obtained through the synthesis operator. Based on the information transmitted by the information data processing module, the SCRI, TCRI and STCRI are updated regularly, and the collision risk and whether the own ship should take collision avoidance actions are judged based on the relevant collision risk index.

[0135] The collision risk assessment module continuously provides the latest spatiotemporal collision risk and collision avoidance action reminders based on updated channel environment information and the real-time status of the own ship and other ships.

[0136] A ship encounter spatiotemporal risk assessment system considering the influence of the navigation environment includes a data acquisition module 1, an encounter collision parameter calculation module 2, a collision risk calculation module 3, and a ship collision risk assessment module 4;

[0137] The data acquisition module 1 is used to obtain the channel environment information of the ship's navigation area and the ship's own position, heading and speed information through the ship environment perception module and positioning module;

[0138] Environmental Perception Module: This module uses marine radar and the Automatic Identification System (AIS) to obtain information about surrounding vessels and navigable areas. The AIS automatically exchanges important information with other vessels, including position, speed, heading, name, and call sign. For smaller vessels that cannot accommodate larger environmental perception modules like marine radar, sensors such as lidar and binocular vision systems can be used in place of radar.

[0139] Positioning module: obtains the ship's position, speed and heading information through the Beidou integrated device and integrated navigation, transmits it to the information data processing module, and provides time-varying ship status information to the collision risk assessment module;

[0140] Navigable ships: receive evasive action instructions, execute control mechanisms, and navigate according to prescribed instructions.

[0141] The collision parameter calculation module 2 is used to calculate the closest encounter distance DCPA of the two ships and the encounter time TCPA from the current position of the ship to the closest intersection point of the two ships based on the channel environment information in the navigable area and the ship's own position, heading and speed information;

[0142] The encounter collision parameter calculation module is further configured to calculate a safe encounter distance d1, an absolute safe encounter distance d2, a latest avoidance distance D1 and an avoidable distance D2 according to the channel environment information in the navigable area and the position, heading and speed information of the ship itself;

[0143] The collision risk calculation module 3 is configured to calculate a spatial collision risk index SCRI and a time collision risk index TCRI according to the distance and time calculated in step two and step three;

[0144] The ship collision risk evaluation module 4 is configured to evaluate the risk of ship collision according to the spatial risk index SCRI, the time risk index TCRI and the space-time collision risk index STCRI.

[0145] The environment perception module of the present application acquires the channel environment information of the sea area where the ship sails, receives task information and processes and optimizes various data, and updates the channel environment information at regular intervals, thereby providing the collision risk evaluation module with time-varying channel environment information and the current position, speed and heading information of the ship.

[0146] Although the present application is described herein with reference to particular embodiments, it is to be understood that these examples are merely illustrative of principles and applications of the present application. It will thus be appreciated that numerous modifications can be made to the illustrative embodiments and that other arrangements can be devised without departing from the spirit and scope of the present application as defined by the appended claims. It will be understood that different embodiments can be combined in different ways than the combinations explicitly discussed herein. It will also be appreciated that features described with respect to one embodiment can be used in other embodiments.

Claims

1. A method for assessing the temporal and spatial risk of ship encounters considering the impact of the navigation environment, characterized in that: include: Step 1: Obtain the channel environment information of the ship's navigation area and the ship's own position, heading and speed information through the ship environment perception module and positioning module; Step 2: Calculate the closest approach distance DCPA and the approach time TCPA from the current position of the ship to the closest point of intersection based on the channel environment information within the navigable area and the ship's own position, heading, and speed information; Based on the channel environment information within the navigable area and the ship's own position, heading and speed information, the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1 and the avoidance distance D2 where measures can be taken are calculated. Step 3: Using the distance and time calculated in step 2, calculate the collision risk level SCRI in spatial position and the collision risk level TCRI of the two ships in the time dimension; Step 4: Use the synthesis operator to combine the spatial risk index SCRI and the temporal risk index TCRI to calculate the spatiotemporal collision risk index STCRI. Step 5: Assess the risk of ship collision based on the spatial risk index (SCRI), temporal risk index (TCRI), and spatiotemporal collision risk index (STCRI); In step 4, the space-time collision risk STCRI is: Where, is a composite operator, and the specific composite rules are: (1) If SCRI is 0, then STCRI is 0; (2) If SCRI is not 0 and TCRI is 0, then STCRI is 0; (3) If both SCRI and TCRI are not 0, then STCRI is the larger value of SCRI and TCRI; In step 5, the method for assessing the risk of ship collision is: When SCRI = 0, there is no risk of collision between the two ships; When SCRI>0 and STCRI=0, the risk of collision between the two ships begins to arise; the give-way vessel needs to take collision avoidance action according to the International Regulations for Preventing Collisions at Sea; When STCRI>0, the collision risk is increasing. The give-way vessel still needs to take action to avoid collision, while the direct-traveling vessel is allowed to take collision avoidance action to avoid collision. When STCRI=0 or the rate of change of TCRA is greater than 0, the collision avoidance risk gradually decreases.

2. The method for assessing the temporal and spatial risk of a ship encounter considering the influence of the navigation environment according to claim 1 is characterized in that: In step 2, the closest approach distance DCPA of the two ships is: Among them, V0 is the speed of the ship; V t For the speed of his ship; is the heading angle of own ship; is the heading angle of the other ship; θ is the azimuth of the other ship relative to the own ship; r is the relative distance between the other ship and the own ship.

3. The method for assessing the temporal and spatial risk of a ship encounter considering the influence of the navigation environment according to claim 2, characterized in that: In step 2, the encounter time TCPA of the ship from its current position to the closest intersection point of the two ships is:

4. The method for assessing the temporal and spatial risk of a ship encounter considering the influence of the navigation environment according to claim 3 is characterized in that: In step 2, the safe encounter distance d1 and the absolutely safe encounter distance d2 of the two ships are: d2=K1·d1 Where W is the channel width; D is the ship width; E is the current visibility; L is the ship length; R is the distance between the two ships; V r It is the relative speed of the two ships in the encounter, and K1 represents the distance expansion coefficient caused by the adverse environment.

5. The method for assessing the temporal and spatial risk of a ship encounter considering the influence of the navigation environment according to claim 4 is characterized in that: In step 2, the latest avoidance distance D1 and the avoidance distance D2 that can be avoided are: D2=K2·D1.

6. The method for assessing the temporal and spatial risk of a ship encounter considering the influence of the navigation environment according to claim 5, characterized in that: In step 3, the collision risk level SCRI in spatial position is:

7. The method for assessing the temporal and spatial risk of a ship encounter considering the influence of the navigation environment according to claim 6, characterized in that: In step 3, the collision risk level TCRI of the two ships in the time dimension is:

8. A system for assessing the temporal and spatial risk of ship encounters considering the impact of the navigation environment, implemented based on the method described in any one of claims 1 to 7, characterized in that: It includes a data acquisition module (1), a collision parameter calculation module (2), a collision risk calculation module (3), and a ship collision risk assessment module (4); The data acquisition module (1) is used to obtain the channel environment information of the ship's navigation area and the ship's own position, heading and speed information through the ship environment perception module and the positioning module; The encounter and collision parameter calculation module (2) is used to calculate the closest encounter distance DCPA of the two ships and the encounter time TCPA from the current position of the ship to the closest intersection point of the two ships based on the ship's own position, course and speed information in the channel environment information within the navigable area; The collision parameter calculation module is also used to calculate the safe encounter distance d1, the absolutely safe encounter distance d2, the latest avoidance distance D1 and the avoidance distance D2 that can be avoided based on the channel environment information in the navigable area and the ship's own position, heading and speed information; The collision risk calculation module (3) is used to calculate the collision risk level SCRI in the spatial position and the collision risk level TCRI of the two ships in the time dimension using the distance and time calculated in step 2 and step 3; The ship collision risk assessment module (4) is used to assess the risk of ship collision based on the spatial risk index SCRI, the temporal risk index TCRI and the spatiotemporal collision risk index STCRI.

Images