Ship encounter sector space-based risk degree space analysis method

Abstract

The invention relates to a ship encountering sector space risk degree space analysis method, which comprises the following steps of: establishing a ship encountering sector space model by taking a ship as a center and taking a detection distance R set by a ship-borne radar as a radius; according to the time gradient range, a sea area space, threatening the main ship, of the target ship is established, judgment is carried out according to the approaching coefficient when the two ship fields are tangent, namely the scaling multiple when the distance is closest, and the scaling multiple lt when the distance is closest; 1, continuing the following steps; determining an encounter fan-shaped space set GP after the target ship G is segmented and an encounter fan-shaped space set QP after the main ship Q is segmented; preliminarily judging the relative positions of the two ships according to the DCPA of the ship and the target ship; the minimum vector distance of the two ships is determined according to the relative heading of the two ships, and the space approaching degree of the combined sector GP is calculated. The method is an analysis method which can simplify a ship encounter space vector structure and accurately excavate and extract encounter space situations and space features of ships in different directions.

Description

Technical Field

[0001] The present invention belongs to the field of fully automated products and relates to a method for spatial analysis of the risk degree of a ship encounter fan-shaped space. Background Art

[0002] With the continuous progress of intelligent navigation technology and intelligent technology for navigation safety assurance, the intelligent ship navigation safety technology has become a key technology for the future ocean that has attracted global attention. Against this background, the safety issue of ship encounters during navigation has become increasingly prominent. Currently, one of the key technologies that urgently need to be broken through in the field of intelligent ships is the method for analyzing the risk of ship encounters. When a ship sails in various waters, it is inevitable to encounter various complex situations. Especially in busy waters, due to the large number of surrounding ships or navigation obstacles, the navigation space shows a complex and crisscrossed, high-density distribution. In such an environment, the spatial relationship of ship encounters becomes complex, chaotic, and variable, and the changing rules of the dynamic time and space domain of encounters and the unknown non-linear spatial characteristics are difficult to fully understand, thus making it difficult to accurately analyze the navigation risk. Therefore, improving the spatial analysis ability of ship navigation safety is of crucial significance for improving the intelligent navigation technology level of ships and even promoting the construction of the intelligent ship system. The improvement of this ability will help intelligent ships better cope with the complex and changing navigation environment, ensure navigation safety, and inject new vitality into the development of intelligent navigation technology.

[0003] Therefore, it is necessary to design a method for spatial analysis of the risk degree of a ship encounter fan-shaped space to solve the above problems. Summary of the Invention

[0004] To solve the above problems, the technical solution adopted by the present invention is: a method for spatial analysis of the risk degree of a ship encounter fan-shaped space, including the following steps:

[0005] S1: Taking the own ship as the center and the detection distance R set by the on-board radar as the radius, establish a ship encounter fan-shaped space model;

[0006] S2: Combining the calculation results of the ship approaching speed, encounter risk parameters, and relative spatial position distribution, establish the sea area space that poses a threat to the main ship by the target ship according to the time gradient range, that is, the ship encounter fan-shaped time and space domain;

[0007] S3: Calculate the encounter parameters of the ship encounter fan-shaped time and space domain: the DCPA between the own ship and the target ship and the TCPA between the own ship and the target ship;

[0008] S4: When TCPA < 0, the target ship has passed the closest encounter point of the two ships; return to calculate the TCPA between the next target ship and the own ship;

[0009] When TCPA ≥ 0, the target ship has not reached or has just reached the closest encounter point of the two ships, and calculate the approaching coefficient when the two ship domains are tangent.

[0010] S5: Determine according to the approaching coefficient when the two ship domains are tangent, that is, the scaling factor when the distance is the closest. When the scaling factor when the distance is the closest < 1, continue with the following steps;

[0011] S6: Determine the set of meeting sector spaces GP after the target ship G is divided, and the set of meeting sector spaces QP after the host ship Q is divided;

[0012] S7: Initially judge the relative positions of the two ships according to the DCPA between the own ship and the target ship;

[0013] S8: Determine the minimum vector distance between the two ships according to the relative headings of the two ships, and realize the spatial approaching degree of the calculated combined sector GP.

[0014] A method for spatial analysis of the danger degree of the meeting sector space of ships provided by the present invention has the following advantages:

[0015] The core of this method lies in constructing a dual-unit meeting sector dynamic space model with multiple time-spaces, multiple angles, and multiple postures. The analysis and calculation of the spatial geometric characteristics and spatio-temporal variation laws of potential meeting dangers in the multi-time-space sequence process provide an innovative new idea for improving the safety analysis ability of the unmanned ship intelligent navigation system.

[0016] Based on the ship navigation meeting state in the multi-time-space scenario, the method establishes a dual-unit meeting sector dynamic space model to realize the GIS vectorization conversion expression of the meeting space. Then, based on the constructed meeting sector spatio-temporal domain, taking the small sector as the unit, deeply analyze and extract the potential spatio-temporal danger characteristics and spatial approaching degree, and effectively extract the geometric spatio-temporal characteristics of potential meeting dangers in multiple time series.

[0017] This method is an analysis method that can simplify the vector structure of the ship meeting space, accurately mine and extract the meeting space situation and spatial characteristics of ships in different directions. With its high-level analysis ability based on spatio-temporal geometric position information, it is a high-order spatial analysis method. It is a high-order spatial analysis method that can solve problems such as reasoning about navigation space relationships, extracting meeting safety space characteristics, and mining adjacent characteristics of navigation situation space, and performs excellently especially in complex scenarios such as multiple obstacles and high density encountered in intelligent navigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the equal-sector and 48-sector division principle of the method of the present invention;

[0020] Figure 2 It is a vector diagram for calculating dangerous parameters based on the meeting sector of ships of the present invention;

[0021] Figure 3 It represents a vector diagram for calculating collision risk information based on the meeting sector space model of ships in the multi-target ship scenario;

[0022] Figure 4 It intuitively shows the calculation and analysis vector diagram of the approaching relationship in the ship meeting space; (a) Equal-sector schematic diagram, (b) Schematic diagram of the 48-sector division principle. Specific implementation manner

[0023] A method for spatial analysis of the risk degree of the meeting sector space of ships includes the following steps:

[0024] S1: Taking the own ship as the center and the detection distance R set by the on-board radar as the radius, establish a meeting sector space model of ships;

[0025] S2: Combining the calculation results of the ship approaching speed, meeting risk parameters, and relative spatial position distribution, establish the sea area space where the target ship poses a threat to the main ship according to the time gradient range, that is, the meeting sector space-time domain of ships; The approaching speed is the relative speed, the meeting risk parameters are the minimum meeting time and the minimum meeting distance, and the relative position distribution is the assumed spatial coordinates

[0026] S3: Calculate the meeting parameters of the meeting sector space-time domain of ships: the DCPA between the own ship and the target ship and the TCPA between the own ship and the target ship;

[0027] S4: When TCPA < 0, the target ship has passed the closest meeting point of the two ships; return to calculate the TCPA between the next target ship and the own ship;

[0028] When TCPA ≥ 0, the target ship has not reached or has just reached the closest meeting point of the two ships, and calculate the approaching coefficient when the two ship domains are tangent;

[0029] S5: According to the approaching coefficient when the two ship domains are tangent, that is, the scaling factor when the distance is the closest, make a judgment. When the scaling factor when the distance is the closest < 1, continue the following steps;

[0030] S6: Determine the set GP of the meeting sector space after the target ship G is divided, and the set QP of the meeting sector space after the main ship Q is divided;

[0031] S7: Initially judge the relative position of the two ships according to the DCPA between the own ship and the target ship;

[0032] S8: Determine the minimum vector distance between two ships according to their relative headings, and realize the spatial approximation degree of the calculated combined sector GP.

[0033] Establish a dynamic space model of the meeting sector with the center of the master ship as the origin. We use [0,1] to represent the boundary of the spatio-temporal domain of the meeting sector as the range of the collision risk perceived by the driver. Secondly, use the moment when the own ship intrudes into the meeting sector space model of the target ship and the moment when it leaves the meeting sector space model of the target ship to construct the time gradient range of the spatio-temporal domain of the meeting sector.

[0034] To calculate the dynamic and static parameters when two ships meet, this method assumes that the own ship S 0 has a ship speed of V 0 , a heading of θ 0 , and the position coordinates of the master ship are (X 0 , Y 0 ). The target ship S 1 has a ship speed of V 1 , a heading of θ 1 , and the position coordinates of the target ship are (X 1 , Y 1 ). The Euclidean distance between the two ships is D. Figure 1 Represents the calculation vector diagram of the meeting risk information based on the dynamic space model of the ship meeting sector. The components of the own ship's speed on the coordinate axes are: Similarly, the components of the target ship's speed on the coordinate axes are: The components of the relative speed of the target ship to the own ship on the coordinate axes are respectively: Then the magnitude of the relative speed is:

[0035] The Euclidean distance, relative angle and other parameters between the master ship and the target ship can be expressed as:

[0036]

[0037] Among them, in the formula, α 1 ——Complementary angle of the relative speed azimuth, The true azimuth of the target ship relative to the own ship is:

[0038]

[0039] The calculation methods of the DCPA and TCPA between the own ship and the target ship are expressed as:

[0040] DCPA = D·sin(ψ 1 -α 1 -π) TCPA = D·cos(ψ 1 -α 1 -π) / v R

[0041] When TCPA > 0, it indicates that the target ship has not reached the closest point of approach of the two ships; conversely, when TCPA < 0, the target ship has passed the closest point of approach of the two ships; when TCPA = 0, the target ship has just reached the closest point of approach of the two ships. When the target ship passes the bow of the own ship from the port side of the own ship, the DCPA value is negative, and when it passes the stern of the own ship, it is positive; while when the target ship passes the bow of the own ship from the starboard side of the own ship, its value is positive, and when it passes the stern of the own ship, it is negative.

[0042] This method comprehensively considers the course, navigation speed and size of the target ship. The introduction of the encounter uncertainty parameter U can improve the ability to identify the danger of moving targets. It is more vigilant about the oncoming ships in the crossing situation and more in line with the relevant regulations of the International Regulations for Preventing Collisions at Sea (COLREGS). Taking the own ship as the main body, a ship fan-shaped area is developed, and the space analysis of the ships near the own ship is carried out to predict the different route trajectories of different ships in different scenarios. Figure 2 It represents the vector diagram of the calculation of collision risk information based on the ship encounter fan-shaped space model in the multi-target ship scenario.

[0043] Furthermore, the process of obtaining the formula for the scaling factor of the ship encounter fan-shaped space model is as follows

[0044] First, assume that the course of the own ship is θ 0 , the size of the fan-shaped ship area is a, that is, the long radius, b is the short radius, the ship speed is V 0 , the ship position coordinates are (X 0 , Y 0 ), (X′ 01 , Y′ 01 ). Establish a rectangular coordinate system with the course of the own ship as the Y-axis direction. The ship position coordinates in the new coordinate system are (X′ 0 , Y′ 0 ); the course of the target ship is θ 1 , the ship speed is V 1 The ship position coordinates are (X 1 , Y 1 ), (X′ 11 , Y′ 11 ) are the initial ship position coordinates of the target ship, and the new ship position coordinates in the new coordinate system are (X′ 1 , Y′ 1 ). Assume the function U(i) of the distance between the own ship and the target ship changing with time;

[0045] The radii of the fan-shaped ship area centered on the own ship are a and b. The relationship between the two coordinate systems is as follows:

[0046]

[0047] The relative course of the two ships is:

[0048] θ = θ1 -θ 0

[0049] When the target ship is located on the boundary of the ship domain of the own ship, in other words, when the ship domain of the own ship is multiplied by the approaching coefficient U such that the target ship is exactly located on the boundary of the ship domain, it is expressed by the following formula:

[0050] (X′ 1 -X′ 0 ) 2 +(Y′ 1 -Y′ 0 ) 2 =(Ur) 2

[0051] The new ship position coordinates of the own ship in the new coordinate system are (X′ 0 , Y′ 0 ); the new ship position coordinates of the target ship in the new coordinate system are (X′ 1 , Y′ 1 );

[0052] Assume that when the own ship is the overtaken ship, R 1 =R 3 =4L, where R1 is the radius of the sector formed by the bow in the combined sector, R3 is the radius of the sector formed by the stern in the combined sector, and L is the ship length

[0053] When the own ship and the other ship form a head-on situation, R 1 =6.4L R 3 =1.6L;

[0054] Considering the two factors of the maximum safe water area radius of the ship and the saved meeting water area range, the long radius of the sector ship domain is 6.4L, and the short radius is 1.6L, then there is:

[0055]

[0056] By simplification, it is equivalent to:

[0057]

[0058] U represents the scaling factor of the meeting sector space. If U is less than 1, it means that there is danger in the meeting sector space at this time;

[0059] Converted to the initial coordinate expression:

[0060]

[0061] When the own ship and the target ship sail at their original headings and speeds, the coordinate change values of the two ships are respectively:

[0062]

[0063] Substituting the above equation into the expression of the coefficient U, we can obtain:

[0064] U(i) 2 = Ni 2 + Pi + Q

[0065] where i represents time, and N, P, and Q are proportionality coefficients of functions with respect to i respectively. According to the physical meanings of the various parameters of this ship in the coordinate system, we can obtain:

[0066] v 0x = v 0 sinθ 0

[0067] v 0y = v 0 cosθ 0

[0068] Similarly, we can obtain:

[0069] v 1x = v 1 sinθ 1

[0070] v 1y = v 1 cosθ 1

[0071] Let the direction component coefficient

[0072] k 1 = sinθ 0 , k 2 = cosθ 0

[0073] The relationship between the various coordinates can be simplified and expressed as:

[0074] x = X 11 - X 01

[0075] y = Y 11 - Y 01

[0076] We can obtain:

[0077]

[0078] Taking the derivative of the function of U and according to the derivative operation, we can obtain:

[0079]

[0080] Let the derivative of the above equation be zero, and by derivation, we can obtain:

[0081]

[0082] When the function U has a minimum value, U min represents a navigation state of the target ship relative to the own ship and is the minimum value of the scaling factor of the ship encounter sector space model.

[0083] The ship encounter sector space dynamic approach degree analysis method uses the space approach theory to establish a ship encounter sector dynamic approach relationship analysis model Q b , which is used to reason and calculate the space approach relationship of the combined sectors in the ship encounter space. Based on the ship encounter space approach theory, an analytical method suitable for representing the approach relationship of the combined sector ship domains is created. This model can accurately depict the approach relationship of ships in the encounter space. Using the space information platform, the main ship is taken as a point layer, and the irregular polygon composed of two sectors with different radii in the free space is taken as the approach object to be analyzed. Subsequently, the dynamic approach degree analysis model is used to calculate one by one the approach relationships between the encounter spaces formed by different target ships and the main ship. Figure 3 Ship encounter sector space dynamic approach relationship calculation and analysis vector diagram;

[0084] The minimum vector distance between two ships is determined according to their relative headings to realize the calculation of the space approach degree of the combined sector GP as follows:

[0085] Assuming the information of the target ship G and the main ship Q, GP = {gp 1 , gp 1 ′, gp 2 ″...} represents the set of encounter spaces after the target ship G is divided, and QP = {qp 1 , qp 1 ′, qp 2 ″...} represents the set of encounter spaces after the main ship Q is divided; QP and GP include the two-dimensional point set P = {p1, p2... pn, p1′, p2′... pn,...}, and these sets are composed of all two-dimensional point sets that make up the sectors of the encounter space; To calculate Figure 4 the space approach relationship between the main ship and the convex hull set of GP, the calculation method of the sector GP and the nearest point is first defined:

[0086]

[0087] The above formula NN GP (q) represents the subset of the nearest points between the main ship q and the convex hull set of GP, D(q, gp i ) represents the Euclidean distance between the main ship q and the convex hull set of GP, and gp i represents an element in the convex hull set of GP;

[0088] Calculate the shortest distance from a point to a point on the edge of a combined sector. Any point on each edge has its own shortest distance pointing to the center inside the combined sector, which is its corresponding shortest sector radius. Next, the specific spatial approach magnitude can be calculated. According to Figure 4 In [reference], there are the spatial polygons QP and GP of ship encounters. The spatial approach distance and spatial approach degree S GP (x) between the target point and the spatial polygon of ship encounters are calculated as follows

[0089] S GP (x) = Min: [D(x, gp 1 ), D(x, gp 2 ),..., D(x, gp i )]

[0090] Q b = S(x) t2 - S(x) t1 / △t

[0091] In the above formula, S GP (x) represents the minimum distance from the target point X to the set of visible edges T, that is, the spatial approach distance; Q b represents the spatial approach degree of the combined sector GP, S(x) t1 represents the sector at the first moment, S(x) t2 represents the sector at the second moment, △t represents a time period; if Q b has a larger value, it indicates that the encounter space is more dangerous for point X.

[0092] The process of preliminarily judging the relative position of the two ships according to the DCPA between the own ship and the target ship is as follows:

[0093] If DCPA < 0, the target ship passes the bow or stern of the own ship from the left side of the own ship; if DCPA > 0, the target ship passes the bow or stern of the own ship from the right side of the own ship.

[0094] Furthermore, it also includes that when the relative course θ of the two ships ∈ [67.5°, 292.5°], then S GP (x) = r = 6.4L; if θ ∈ [0°, 67.5°) ∪ (292.5°, 360°], then S GP (x) = r = 4L.

[0095] Example 1: This example proposes a spatial analysis method based on the spatial risk degree of the ship encounter sector space. Figure 4The encounter space is divided into a series of equiangular fan-shaped regions, (a) equal sectors, (b) schematic diagram of the 48-sector division principle. Each fan-shaped region has a common center point, and the center point is connected to the spatial radiation lines at a constant mathematical distance. The position points on each radiation line are associated with the mathematical distance from the center point. When a ship is navigating in a crowded and dense water area (such as near-shore navigation, inland river navigation), the navigation water area contains obstacles and target ships, resulting in problems such as a high risk of encounter, high spatial ambiguity, and discrete and complex spatial relationships. Then, according to Figure 4 In the calculation with the fan-shaped region as the spatial unit, in the figure, taking the center of the main ship as the origin, three concentric circles are drawn with radii of 1 / 3r meters, 2 / 3r meters, and r meters respectively (R is the detection distance set by the shipborne radar). Taking 11.25 degrees west of north as the starting point, 16 sectors with equal included angles are drawn, and they are successively divided into 48 fan-shaped spaces. The angular bisector of each sector included angle is used as the direction indicated by the sector. The corresponding directions of each sector are as follows: The N1, N2, and N3 sectors represent due north, the NNE1, NNE2, and N3 sectors represent north-northeast (22.5 degrees east of north), the NE1, NE2, and NE3 sectors represent northeast (45 degrees east of north), the NEE1, NEE2, and NEE3 sectors represent east-northeast (67.5 degrees east of north); the E1, E2, and E3 sectors represent due east, the SEE1, SEE2, and SEE3 sectors represent southeast by east (22.5 degrees south of east), the SE1, SE2, and SE3 sectors represent southeast (45 degrees south of east), the SSE1, SSE2, and SSE3 sectors represent southeast by south (67.5 degrees south of east); the S1, S2, and S3 sectors represent due south, the SSW1, SSW2, and SSW3 sectors represent southwest by south (22.5 degrees west of south), the SW1, SW2, and SW3 sectors represent southwest (45 degrees west of south), the SWW1, SWW2, and SWW3 sectors represent southwest by west (67.5 degrees west of south); the W1, W2, and W3 sectors represent due west, the NWW1, NWW2, and NWW3 sectors represent northwest by west (22.5 degrees west of north), the NW1, NW2, and NW3 sectors represent northwest (45 degrees west of north), and the NNW1, NNW2, and NNW3 sectors represent northwest by north.

[0096] A spatial analysis method for the risk degree of ship encounter fan-shaped space includes the following steps:

[0097] S1: Initialize all ship navigation motion parameters V n , C n , the spatial position X n , Y n ;

[0098] S2: Initialize the number of ships N within a certain range, and set the relative coordinates X of the surrounding shipsn (t), Y n (t);

[0099] S3: When N = 1, execute;

[0100] S4: Obtain the relative course θ of the two ships, θ = θ 1 - θ 0 ;

[0101] S5: Obtain the distance between the two ships, and calculate the relative motion encounter parameters TCPA and DCPA of the ships;

[0102] S6: If TCPA < 0, the target ship has passed the closest point of approach of the two ships, then the operation ends and the analysis result is stored;

[0103] If TCPA ≥ 0, it means that the target ship has not reached or has just reached the closest point of approach of the two ships, then proceed to the next calculation;

[0104] S7: Obtain the approach coefficient U when the domains of the two ships are tangent;

[0105] S8: The function of the distance between the own ship and the target ship changing with time,

[0106] U(i) 2 = Ni 2 + Pi + Q

[0107] Scaling factor when the distance is the closest Greater than 1, not invaded; equal to 1, just invaded / invading ends; less than 1, already invaded

[0108] S9: Determine the set of encounter sector spaces GP = {gp 1 , gp 1 ′, gp 2 ″…} after the target ship G is divided, and the set of encounter sector spaces QP = {qp 1 , qp 1 ′, qp 2 ″…} after the host ship Q is divided;

[0109] S10: Initially judge the relative position of the two ships according to DCPA. If DCPA < 0, the target ship passes the bow or stern of the own ship from the port side of the own ship; if DCPA > 0, the target ship passes the bow or stern of the own ship from the starboard side of the own ship.

[0110] S11: Determine the minimum vector distance S GP (x) of the two ships according to the relative course of the two ships. If

[0111] θ ∈ [67.5°, 292.5°], then S GPS(x) = r = 6.4L; if θ ∈ [0°, 67.5°) ∪ (292.5°, 360°], then S GP S(x) = r = 4L;

[0112] S12: Calculate the spatial approximation degree Q of the combined sector GP b = S(x) t2 - S(x) t1 / Δt;

[0113] S13: Execute when N ≥ 2; perform loop calculations according to formulas (5)-(14); obtain the risk degree between other target ships and itself.

Claims

1. A spatial analysis method based on the danger level of a ship encountering a sector space, characterized by: The following steps are involved: S1: With the ship as the center and the detection distance R set by the shipborne radar as the radius, a fan-shaped space model of the ship encounter is established; S2: Based on the calculation results of the ship approach speed, the hazard parameters and the relative spatial position distribution, the sea area where the target ship poses a threat to the host ship is established according to the time gradient range, that is, the ship encounters the fan-shaped space-time domain; S3: Calculate the encounter parameters of the ship encounter sector space-time domain: DCPA between the own ship and the target ship and TCPA between the own ship and the target ship; S4: When TCPA<0, the target ship has passed the closest encounter point between the two ships; return to calculate the TCPA between the next target ship and the own ship; When TCPA ≥ 0, the target ship has not arrived or has just arrived at the closest encounter point between the two ships, and the approach coefficient when the two ship fields are tangent is calculated; S5: judging according to the approach coefficient when the two ship areas are tangent, that is, the zoom factor when the distance is closest, when the zoom factor when the distance is closest is less than 1, continuing with the following steps; S6: Determine the encounter sector space set GP after the target ship G is segmented, and the encounter sector space set QP after the host ship Q is segmented; S7: Preliminarily determine the relative positions of the two ships based on the DCPA of the own ship and the target ship; S8: Determine the minimum vector distance between the two ships according to their relative headings, and realize the spatial approach degree of the calculated combined fan-shaped GP.

2. According to claim 1, a spatial analysis method based on the danger level of a ship encountering a sector space is characterized by: The expression of the scaling factor U of the fan-shaped space model encountered by the ship is as follows: If U is less than 1, it means that there is danger in the fan-shaped space at this time; the ship position coordinates are (X0, Y0), and the new coordinate system new ship position coordinates are (X′1, Y′1); in: θ is the relative heading of the two ships: θ=θ1-θ0 Where: θ0 is the heading of own ship, θ1 is the heading of target ship.

3. According to claim 1, a method for analyzing the danger of a ship encountering a sector space, characterized in that: The minimum vector distance between the two ships is determined according to the relative headings of the two ships, and the degree of spatial proximity to the calculation of the combined fan-shaped GP is achieved as follows: Assuming the information of the target ship G and the main ship Q, GP = {gp1, gP1′, gP2″...} represents the encounter space set after the target ship G is segmented, and QP = {qp1, qp1′, qp2″...} represents the encounter space set after the main ship Q is segmented; QP and GP include two-dimensional point sets P = {p1, p2...pn, p1′, p2′...pn,...}, which are composed of all two-dimensional point sets that constitute the encounter space fan; in order to calculate the spatial proximity relationship between the main ship and the convex hull set of GP, the calculation method of the fan GP and the nearest neighbor point is first defined: The above formula NN GP (q) represents the subset of the nearest points between the main ship q and the convex hull set of GP, D(q, gP i ) represents the Euclidean distance between the main ship q and the convex hull set of GP, gP i Represents the elements in the GP convex hull set; The shortest distance from the calculated point to a point on the edge of the combined sector. Any point on each edge has its own shortest distance to the center of the combined sector, which is the corresponding shortest sector radius. According to the ship encounter space polygon QP and GP, the spatial proximity distance and spatial proximity degree S between the target point and the ship encounter space polygon GP (x) is calculated as follows S GP (x)=Min:[D(x,gp1),D(x,gp2),...,D(x,gp i )] Q b =S(x) t2 -S(x) t1 / Δt In the above formula, S Gp (x) represents the minimum distance from the target point X to the visible edge set T, that is, the spatial approach distance; Q b Indicates the spatial proximity of the combined sector GP, S(x) t1 represents the sector at the first moment, S(x) t2 represents the sector at the second moment, Δt represents a time period; if Q b The larger the value is, the greater the danger of this encounter space to point X.

4. According to claim 1, a method for analyzing the danger of a ship encountering a sector space, characterized in that: It also includes when the relative heading of the two ships θ∈[67.5°, 292.5°], then S Gp (x) = r = 6.4 L; If θ∈[0°,67.5°)∪(292.5°,360°], then S GP (x)=r=4L.

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