Target ship interception method based on speed obstacles

Abstract

The invention discloses a target ship interception method based on speed obstacles, which can comprehensively meet law enforcement tracking requirements of official ships in a complex environment, and is particularly suitable for high-risk areas such as narrow channels and port waters. By predicting the possible position of the tracking target in the future, the problem that time calculation of the prediction tracking target has deviation is solved; meanwhile, the relative motion relation between the ship and an obstacle is quantitatively analyzed by establishing a speed obstacle model, and the collision possibility is reduced; in addition, the collision avoidance weights of different obstacles can be determined according to the danger levels of the different obstacles. Through the synergistic effect of the method, the advancing direction of the intercepted target can be optimally predicted, various obstacles can be effectively avoided, an optimal collision avoidance interception path considering safety and economy is generated in real time, meanwhile, the collision avoidance strategy can be dynamically adjusted by identifying and classifying the navigation risk levels of the obstacles, and the collision avoidance efficiency is improved. The occurrence rate of collision accidents on the sea is greatly reduced, and it is ensured that the target ship can be intercepted rapidly and safely.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of ship navigation, and particularly relates to a target ship interception method based on speed obstacles. BACKGROUND

[0002] As the core equipment of the national maritime administrative law enforcement force, official vessels are the key law enforcement platforms for government functional departments to perform maritime official duties. These modernized law enforcement vessels, which shoulder the national mission, bear major responsibilities such as maintaining national maritime rights and interests, ensuring maritime safety order, and cracking down on illegal and criminal activities, and especially play an irreplaceable role in key law enforcement fields such as maritime patrol supervision, smuggling suppression, and emergency rescue. In such high-demand law enforcement scenarios, official vessels must have excellent capabilities for efficient tracking, accurate interception, and effective control of suspicious target vessels.

[0003] However, when generating tracking and interception routes through the current prior art, there are still certain limitations in dealing with multiple targets and high-dynamic scenarios, making it difficult to meet the needs of efficient tracking and interception for official vessels to protect national maritime rights and interests, ensure maritime safety order, and crack down on illegal and criminal activities. SUMMARY

[0004] To solve the above-mentioned problems in the prior art, the purpose of the present application is to provide a target ship interception method based on speed obstacles, which can meet the target tracking needs of official vessels in various scenarios, especially in complex scenarios such as narrow channels and port waters, by predicting the future possible position of the tracking target vessel and optimizing the predicted forward direction of the interception target, thereby effectively improving the time calculation accuracy of the tracking path and solving the problems of prediction lag, inaccurate time calculation of the predicted tracking target, and untimely response in traditional methods. At the same time, by constructing a speed obstacle model, the relative motion relationship between the vessel and obstacles is quantitatively analyzed, and by calculating the collision risk cone of different obstacles in real time, an optimal collision avoidance interception path that takes into account safety and economy is generated, thereby effectively reducing the risk probability of collision between the vessel and other dynamic or static obstacles. In addition, according to the different navigation danger levels of different obstacles, the size of the speed obstacle area and the size of the speed of different obstacles are compared to determine the collision avoidance weight of different obstacles, and by dynamically assigning collision avoidance priorities, a more intelligent obstacle avoidance strategy is achieved, which can significantly reduce the rate of maritime collision accidents and safely and quickly intercept target vessels.

[0005] To achieve the above-mentioned purposes and other related purposes, the present application adopts the following technical solutions:

[0006] The present application provides a target ship interception method based on speed obstacles, comprising the following steps,

[0007] S1, respectively, obtain the target ship current position p T , current speed v T and the current position p o of the ship; at the same time, determine the maximum speed of the ship and the safety radius R O of the ship; wherein the safety radius R O of the ship is the radius of the maximum circumscribed circle of the ship;

[0008] S2, based on the method of multiple iterations, iteratively update the new position of the target ship when meeting the ship until the final position p'kT satisfies the relative distance between the position p'k-1T of the previous iteration is not greater than the set error threshold ε;

[0009] S3, based on the ship reaching the final position p' kT of the target ship, there are multiple dynamic obstacles, and the speed obstacle method is used to construct a speed obstacle model to plan the optimal collision avoidance interception path of the ship to the target ship:

[0010] First, assuming there are i dynamic obstacles, the speed obstacle area VO i of each dynamic obstacle is constructed one by one;

[0011] Then, according to the situation of multiple dynamic obstacles, a weighted obstacle avoidance strategy is adopted: based on considering the different obstacle avoidance weights of each dynamic obstacle, in the speed v not falling within the speed obstacle space VO range, the optimal speed v that can satisfy the ship while avoiding obstacles and as close to the target ship as possible is selected as the ship speed v O ;

[0012] S4, periodically run steps S1 to S3, and the running period is ΔT;

[0013] If the relative distance between the current position p T of the target ship obtained in step S1 and the current position p o of the ship is not greater than the preset interception threshold θ, it is determined that the interception has reached the purpose, and the interception is ended;

[0014] Otherwise, continue to execute steps S2 and S3 to re-plan the optimal collision avoidance interception path of the ship from the current position p o to the current position p T of the target ship.

[0015] As a preferred technical solution, the step S2 includes the following specific steps:

[0016] S2-1, based on the maximum speed of the ship estimate the ship from the current position p o of the ship to the current position pT The required direct time t arrive ;

[0017] S2-2, based on the direct time t arrive , calculate the new position p' of the target ship when meeting with the ship T ;

[0018] S2-3, iteratively update the new position of the target ship until the iteration k times, and the obtained p' kT satisfies ||p' kT -p' k-1T ||≤ε, at this time, the obtained p' kT is the final position of the target ship.

[0019] As a further preferred technical solution, in the step S2-2, if there is no static obstacle in the target ship's sailing direction, the step of calculating the new position p' T of the target ship when meeting with the ship includes:

[0020] Assuming the speed of the target ship is v T ;

[0021] Then after the time t arrive , the new position p' T of the target ship is:

[0022] p' T =p T +v T ·t arrive .

[0023] As a further preferred technical solution, in the step S2-2, if there is a static obstacle in the target ship's sailing direction, the step of calculating the new position p' T of the target ship when meeting with the ship includes:

[0024] According to the point where the static obstacle is located, the positions of each turning point are determined to be p r1 , p r2 , p r3 , p r4 , p r5 ……p rlast ;

[0025] Assuming the speed of the target ship is

[0026] Then the time required by the target ship for each sailing is calculated as follows:

[0027]

[0028] The remaining time t of the target ship after turning at the last turning pointlast for:

[0029] t last =t arrive -t r1 -t r2 -t r3 -...-t rlast

[0030] Thus, the time t is obtained. arrive Afterwards, the target ship's new position p' T for:

[0031] p' T =p rlast +v T ·t last .

[0032] Furthermore, the random turning angles of the target ship at each turning point are δ1, δ2, δ3, δ4..., and the range of the random turning angle δ is the angle at which the target ship can continue to sail, and the random turning angle δ≤30°.

[0033] As a preferred technical solution, in step S3, the velocity obstacle region VO of each dynamic obstacle is constructed one by one. i This includes the following specific steps:

[0034] S3-1, Define the relative velocity v between the i-th dynamic obstacle and the ship. Oi :v Oi =v O -v i , where v O Represents the speed of the own ship, v i Represents the velocity of the i-th dynamic obstacle;

[0035] S3-2, Construct the velocity obstacle region VO of the i-th dynamic obstacle. i :

[0036] Assume the safe radius of the i-th dynamic obstacle is R. i R i Let be the radius of the largest circumcircle of the i-th dynamic obstacle, then used to calculate the velocity obstacle region VO. i The safety radius is R' i :

[0037] R' i =R i +R O

[0038] Then in the future time t arrive Inside, all possible ship speeds v that could lead to a collision O satisfy:

[0039] ||p' T -(p O +v O ·t arrive )|| <R' i

[0040] Converting the above formula into a velocity space, we get all possible ship velocities v that could lead to a collision. O satisfy:

[0041] ||p' T -p O -v O ·t arrive || <R' i

[0042] All ship speeds v calculated using the above formulas O The velocity obstacle region VO that constitutes the i-th dynamic obstacle i .

[0043] As a preferred technical solution, in step S3, a weighted obstacle avoidance strategy is adopted when there are multiple dynamic obstacles, including the following specific steps:

[0044] S3-3. Calculate the obstacle avoidance strategy under multiple dynamic obstacles and obtain the ship's speed v. O :

[0045]

[0046] in:

[0047] VO stands for velocity obstacle space, which is the velocity obstacle area of ​​all dynamic obstacles. i A set;

[0048] v g The ideal speed for intercepting the target ship; v g Size and maximum speed of the ship The same size, v g The direction is the direction of this ship relative to p'kT;

[0049] λ i The obstacle avoidance weights for each dynamic obstacle;

[0050] VO i Let be the speed obstacle region of the i-th dynamic obstacle.

[0051] Furthermore, in step S3-3, the obstacle avoidance weight λ of each dynamic obstacle... i Defined in the following manner:

[0052] First, calculate the spatial VO of each individual dynamic obstacle. i and speed v i The percentage of all dynamic obstacles in the total;

[0053] Then, by using the VO of each of the above dynamic obstacles i Space ratio and v i The obstacle avoidance weight λ for each dynamic obstacle is obtained by summing the corresponding speed ratios one by one and taking the average. i .

[0054] As a further preferred technical solution, in step S3-3, the velocity obstacle space VO is discretized and quantized to traverse and quantize all the evaluation values ​​of the velocities, and the minimum value among the evaluation values ​​is selected as the final velocity.

[0055] Furthermore, the discrete quantization process employs a fan-shaped grid for spatial discretization.

[0056] As described above, the present invention has the following beneficial effects:

[0057] (1) The present invention provides a target vessel interception method based on speed barriers. In the process of tracking and intercepting a target vessel, the target vessel may change speed and direction, especially when navigating in narrow waterways. The target vessel is affected by static targets such as waterways and shorelines, as well as other dynamic vessels, and its speed and direction may change. The present invention anticipates this change and makes a certain probability prediction of the possible speed and direction changes of the target vessel. Through iterative methods, it achieves accurate approximation of the target vessel's position, effectively improving the time calculation accuracy of the tracking path of the vessel. By using this iterative method to make more accurate estimates of the interception position and interception time of the target vessel, it can effectively solve the problems of prediction lag and untimely response in traditional methods and improve tracking accuracy. At the same time, by constructing a speed barrier model, the relative motion relationship between the vessel and surrounding obstacles can be quantitatively analyzed, thereby reducing the probability of collision with dynamic or static obstacles and enhancing collision avoidance capability.

[0058] (2) The target vessel interception method based on speed obstacle of the present invention has the ability to autonomously avoid obstacles in dynamic environments. It can achieve real-time and safe obstacle avoidance in complex sea conditions and dense navigation areas, ensuring the safety and reliability of law enforcement process. By predicting the speed change and direction change of the target vessel, it can make a certain probability prediction of possible changes. Through iterative method, it can make a more accurate estimate of the interception position and interception time of the target vessel. The computational complexity is low, which can reduce the burden of the computing system and is easy to implement in engineering. Based on multi-source information fusion and real-time situational awareness, through the deep integration of artificial intelligence and autonomous decision-making technology, it can intelligently generate the optimal interception route for the target vessel. It can meet the target tracking needs of law enforcement vessels. In various scenarios, especially in complex scenarios such as narrow channels and port waters, it can optimize the prediction of the direction of interception of the target. It provides key technical support for improving the intelligence level of my country's maritime law enforcement equipment. It has important strategic significance for strengthening the modernization of marine governance capabilities and can significantly improve the efficiency and success rate of law enforcement actions.

[0059] (3) The target ship interception method based on speed obstacles of the present invention has online processing capability and can be processed in real time during the navigation of the ship. It can not only provide the latest predicted path based on the real-time position of the ship and the target ship through dynamic real-time calculation, but also perform real-time analysis of the danger level of dynamic obstacles (such as obstacle ships) existing in the interception process of the target ship. It can select collision avoidance weights according to the different navigation danger levels of different dynamic obstacles. That is, it can assign different weights to dynamic obstacles with different speed obstacle space sizes and speeds, thereby dynamically assigning collision avoidance priorities through dynamic weighting, realizing a more intelligent obstacle avoidance strategy. It is beneficial for the ship to stay away from obstacle ships with higher danger levels and to effectively avoid collisions with other obstacles. It can calculate the collision risk cone of different obstacles in real time and generate the optimal collision avoidance interception path that takes into account both safety and economy, giving users a realistic navigation perception, improving navigation safety, and is easy to implement in engineering.

[0060] In summary, this invention achieves efficient interception of target vessels through the following methods: Firstly, it addresses the problem of inaccurate target tracking time calculation by predicting the possible future location of the target. Secondly, it reduces the possibility of collisions with other obstacles by quantitatively analyzing the relative motion between the vessel and obstacles using a speed obstacle model. Thirdly, it determines the collision avoidance weights of different obstacles by comparing the size of their speed obstacle spaces and their speeds, based on the degree of danger of each obstacle. Therefore, through the synergistic operation of these methods, this invention significantly reduces the maritime collision rate while safely and quickly intercepting target vessels. It comprehensively adapts to the law enforcement tracking needs of government vessels in complex environments, and is particularly suitable for high-risk areas such as narrow waterways and port waters. It not only optimizes the predicted direction of the intercepted target but also effectively avoids various types of obstacles. By calculating the collision risk cone of each obstacle in real time, it generates an optimal collision avoidance interception path that balances safety and economy. Furthermore, by identifying and classifying the navigation risk level of obstacles, it dynamically adjusts the collision avoidance strategy, significantly reducing the maritime collision rate while ensuring the target vessel can be intercepted quickly and safely. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of a sector grid in the feasible velocity space of this invention.

[0062] Figure 2 This is a flowchart illustrating a target ship interception method based on speed barriers according to the present invention.

[0063] Figure 3 This is an actual effect diagram of the target ship interception method based on speed obstacle of the present invention. Detailed Implementation

[0064] To better understand the purpose, structure, and function of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0065] In the description of this invention, it should be noted that the positional relationships indicated by terms such as "longitudinal" and "lateral" in this specification are based on the positional relationships shown in the accompanying drawings, and are only for the purpose of facilitating the description of the embodiments of this invention and simplifying the description, so as to more clearly understand its operating principles and workflow. Therefore, they should not be construed as limitations on this invention.

[0066] Example

[0067] like Figure 2 As shown, this embodiment provides a target ship interception method based on speed barriers, including the following steps:

[0068] S1. Obtain the target ship's current position and speed based on the ship's perception system; obtain the ship's current position based on the ship's navigation system; and determine the ship's maximum speed and safe radius based on the ship's design parameters.

[0069] S1-1, Receive the function activation command based on the target ship.

[0070] S1-2. Obtain the current position of the target ship as p through the ship sensing system. T And obtain the target ship's current speed as v. T .

[0071] The ship perception system is used to detect and track the position and speed of the target ship in real time, including but not limited to radar equipment, optoelectronic equipment or automatic identification system (AIS);

[0072] S1-3, Obtain the ship's current position as p through the ship navigation system. o Meanwhile, based on the ship's design parameters, the maximum speed of this ship is... The safety radius is R O Among them, the maximum speed of this ship This is the maximum speed in the ship's design parameters, and the ship's safe radius R. O It is the radius of the largest circumcircle under the design parameters of this ship, that is, the safe radius R of this ship. O The circumscribed circle of the vessel is determined by its maximum outer circle size, which completely covers the outline of the vessel's hull.

[0073] The ship navigation system is used to provide the ship with precise positioning and navigation information, including but not limited to the BeiDou Navigation Satellite System or the Global Positioning System (GPS). In this embodiment, the BeiDou Navigation Satellite System is used as the ship's navigation equipment.

[0074] The positions and speeds of both the ship and the target ship can be decomposed into quantities in two directions:

[0075] p o = (x0, y0),

[0076] p T =(x t ,y t ), v T =(v tx ,v ty )

[0077] In other words, the current position of this ship is defined as two-dimensional coordinate p. o= (x0, y0), where x0 and y0 represent the abscissa and ordinate of the ship in the preset reference coordinate system, respectively; the maximum speed of the ship is defined as a two-dimensional vector. Where v 0x and v 0y These represent the components of the ship's maximum speed in the preset reference coordinate system along the horizontal and vertical axes, respectively; the target ship's current position is defined as the two-dimensional coordinate p. T =(x t ,y t ), where x t and y t These represent the x and y coordinates of the target ship in the preset reference coordinate system, respectively; the target ship's current speed is defined as a two-dimensional vector v. T =(v tx ,v ty ), where v tx and v ty These represent the components of the target ship's current speed in the horizontal and vertical directions within the preset reference coordinate system, respectively.

[0078] S2. Considering that during the process of intercepting the target ship, i.e., before the target ship meets the target ship at the same point in time, there may be situations where the target ship changes course when encountering obstacles, this method calculates the time required for the ship to reach the target ship's current position through multiple iterations, including the following specific steps:

[0079] S2-1, Based on the ship's maximum speed Calculate the distance from the ship's current position p. o Reach the target ship's current position p T Required direct time t arrive :

[0080] First, calculate the relative distance d between our ship and the target ship:

[0081] d=||p T -p O ||

[0082] Then, assuming the ship travels at its maximum speed If the ship is sailing towards the target ship, its maximum speed can be estimated. The direct travel time t required to reach the target ship's current position. arrive for:

[0083]

[0084] S2-2, Based on direct arrival time t arrive Calculate the new position p' of the target ship when it encounters the current ship. T .

[0085] ① Under ideal conditions where there are no static obstacles in the direction of the target ship's navigation, the new position when the target ship meets the ship is calculated as follows:

[0086] Assume the target ship's speed is That is, the component of the target ship's current speed in the horizontal direction in the preset reference coordinate system is set as... And set the component of the target ship's current speed in the vertical direction in the preset reference coordinate system as...

[0087] So, after time t arrive Afterwards, the target ship's new position p' T for:

[0088] p' T =p T +v T ·t arrive

[0089] ② When there are static obstacles in the direction of the target ship's navigation, it should be further explained that when the target ship is traveling in a straight line, it may collide with static obstacles such as land. However, it is difficult for this ship to predict which direction the target ship will turn in the future. Therefore, it is assumed that when the target ship encounters a static obstacle, it will choose a random turning angle δ to rotate. The range of this random turning angle δ is the angle at which the target ship can continue to sail, rather than the angle at which it cannot continue to sail. In principle, the random turning angle δ of the target ship is ≤30°.

[0090] In other words, in practical work, when there is a static obstacle in the target ship's direction of navigation, the target ship may have multiple turning points, each of which is also the location of the static obstacle. The location of the static obstacle can be obtained through the ship's sensing system, and the position of each turning point can be determined based on the location of the static obstacle. r1 p r2 p r3 p r4 p r5 ...p rlast The turning angles of the target ship at each turning point are δ1, δ2, δ3, δ4...

[0091] Therefore, when the target ship may have multiple turning points, the new position p' when the target ship meets the ship is... T The calculation is as follows:

[0092] Assume the target ship's speed is And corresponding to the position p of each turning point r1 p r2 p r3 p r4 pr5 ...p rlast The time required for each leg of the journey by the target ship is t. r1 t r2 t r3 t r4 t r5 ...t rlast ;

[0093] The time required for each segment of the target ship's voyage is calculated as follows:

[0094]

[0095] The remaining time t after the target ship turns at the last turning point last for:

[0096] t last =t arrive -t r1 -t r2 -t r3 -...-t rlast

[0097] Therefore, considering that the target ship has multiple turning points, after time t arrive Afterwards, the target ship's new position p' T for:

[0098] p' T =p rlast +v T ·t last

[0099] S2-3, Iteratively update the target ship's new position until the final position p' of the target ship is obtained. kT This includes the following steps: obtaining the position p' of the target ship. T Then, the target ship's position is updated using multiple iterations until the target ship's final position p' is reached. kT Satisfy ||p' kT -p' k-1T ||≤ε, to achieve a precise approximation of the target ship's position, where k is the iteration number and p' kT Let p' be the new position of the target ship after the k-th iteration. k-1T Let ε be the new position of the target ship after the (k-1)th iteration, and let ε be the preset proximity threshold, which is usually chosen as 0.01 nautical miles.

[0100] Taking the first iteration as an example, after obtaining the position p' of the target ship... T Then, by repeating steps S2-1 to S2-2, the new position p' of the target ship after the first iteration can be obtained. 1T The specific steps are as follows:

[0101] First, calculate the relative distance between our ship and the target ship:

[0102] d1=||p T -p O ||

[0103] Then, assuming the ship travels at its maximum speed Sailing towards the target ship;

[0104] The estimated time required for this ship to reach the target ship's current position is:

[0105]

[0106] Similarly, considering that the target ship has multiple turning points, the remaining time after the target ship turns at the last turning point is:

[0107] t 1last =t 1arrive -t 1r1 -t 1r2 -t 1r3 -...-t 1rlast

[0108] So after time t 1arrive The target ship's new location is as follows:

[0109] p' 1T =p 1rlast +v T ·t 1last

[0110] Subsequently, after obtaining the new location p' of the target ship 1T Then, by repeating steps S2-1 to S2-2, the new position p' of the target ship after the second iteration can be obtained. 2T This process is repeated iteratively until p' is obtained. kT Satisfy ||p' kT -p' k-1T The error threshold ε is generally set to 0.01 nautical miles. The p'kT obtained at this point is the final position of the target ship.

[0111] This invention achieves precise approximation of the target ship's position through an iterative approach, effectively improving the time calculation accuracy of the ship's tracking path, solving the problems of prediction lag and untimely response in traditional methods, and enhancing the accuracy of target prediction.

[0112] S3, Based on the final position p' of the target vessel. kTGiven the presence of multiple dynamic obstacles, the optimal collision avoidance path is calculated using the velocity obstacle method to reach the target ship's final position p'kT, generating a path as follows: Figure 3 The navigation path diagram shown: First, the velocity obstacle region (VO) for each dynamic obstacle is constructed one by one. i Among them, the speed barrier zone VO i This represents the speed at which the ship might collide with the i-th dynamic obstacle; then, based on the situation of multiple dynamic obstacles, a weighted obstacle avoidance strategy is adopted. Specifically, this includes the following steps:

[0113] First, assuming there are i dynamic obstacles, construct the velocity obstacle region VO of the i-th dynamic obstacle. i The specific steps include:

[0114] S3-1, Define the relative velocity v between the i-th dynamic obstacle and the ship. Oi The speed of this ship is v O The velocity of the i-th dynamic obstacle is v i Then the relative velocity is defined as: v Oi =v O -v i

[0115] By defining relative velocity v Oi This allows us to determine the direction and speed of the ship's motion relative to the i-th dynamic obstacle; the relative speed v Oi The direction and magnitude of the obstacle directly affect the relative position change between the ship and the i-th dynamic obstacle; if the relative velocity v Oi If the obstacle points to the vessel's current or future position, then there is a risk of collision between the vessel and the moving obstacle. Therefore, the vessel needs to avoid the collision zone caused by the relative speed of each moving obstacle.

[0116] S3-2, Construct the velocity obstacle region VO of the i-th dynamic obstacle. i :

[0117] Assume the safe radius of the i-th dynamic obstacle is R. i That is, the radius of the largest circumcircle of the i-th dynamic obstacle is used to calculate the safe radius of the speed obstacle region as R'. i ;

[0118] R' i =R i +R O

[0119] Among them, R O This refers to the aforementioned safe radius of the vessel.

[0120] Then in the future time t arriveInside, all possible ship speeds v that could lead to a collision O satisfy:

[0121] ||p' T -(p O +v O ·t arrive )|| <R' i

[0122] Converting the above formula into a velocity space, we get all possible ship velocities v that could lead to a collision. O satisfy:

[0123] ||p' T -p O -v O ·t arrive || <R' i

[0124] This formula can be used to determine the future time t. arrive Within, own ship’s speed v O Position p' of the target ship T The relationship between these factors is used to ensure that the ship does not collide with the i-th dynamic obstacle. In other words, all the ship's velocities v calculated using the above formula are... O Satisfying at time t arrive At that time, the possible position of the target ship is p' T With this ship from its current position p O Depart at speed v O Sailing t arrive The distance between the positions after the time is less than the safe radius R' of the obstacle. i Therefore, all the ship's speeds v calculated using the above formula are... O The velocity obstacle region VO that constitutes the i-th dynamic obstacle i At this time, the ship uses VO which is not in the speed barrier zone. i By maintaining a speed of v, the ship can avoid the i-th dynamic obstacle. In other words, to avoid the i-th dynamic obstacle, the ship's actual speed v during navigation is vi. Speed ​​Obstacle Zone (VO) i .

[0125] Then, for situations involving multiple dynamic obstacles, a weighted obstacle avoidance strategy is adopted, including the following specific steps:

[0126] S3-3. Calculate the obstacle avoidance strategy under multiple dynamic obstacles and obtain the ship's speed v. O for:

[0127]

[0128] in:

[0129] VO stands for velocity obstacle space, which is the velocity obstacle area of ​​all dynamic obstacles. i A set;

[0130] v g The ideal speed for intercepting the target ship; v g The size equals This is the ship's maximum speed; v g The direction is that of this ship relative to p' kT The direction, p' kT This is the final position of the target ship when it encounters this ship, after multiple iterations of calculation in step S2.

[0131] λ i The obstacle avoidance weights for each dynamic obstacle;

[0132] VO i Let be the speed obstacle region of the i-th dynamic obstacle.

[0133] This formula allows us to find, outside the given velocity obstacle space VO, the ship's velocity v among all possible velocities v that minimizes the objective function within the parentheses. O Specifically, the objective function within the parentheses consists of two parts: one is ||vv g || represents the velocity v and the ideal velocity v of the intercepting target ship. g The difference between them is minimized by reducing ||vv g The speed v can be adjusted to be as close as possible to the ideal speed v for intercepting the target ship. g Furthermore, the closer the speed v is to the ideal speed v of the target ship being intercepted... g The faster the pursuit and interception, the higher the interception efficiency; secondly... This represents the velocity v and the velocity obstacle region VO of each dynamic obstacle. i The weighted sum of the reciprocals of the distances between the obstacles emphasizes the importance of obstacle avoidance, thus assigning greater weight to smaller distances. In other words, by summing the reciprocals of the weighted distances of all dynamic obstacles, a comprehensive metric is obtained to assess the safety of speed v. The smaller this metric, the safer the ship's speed v is, meaning the greater the distance from the speed obstacle zones of all dynamic obstacles. In summary, this formula can, based on the different obstacle avoidance weights of each dynamic obstacle, select the optimal speed v from speeds v that do not fall within the speed obstacle space VO, which allows the ship to avoid obstacles while approaching the target ship as closely as possible. O .

[0134] Among them, the obstacle avoidance weight λ for each dynamic obstaclei In other general studies, the choice of obstacle avoidance weight λ for each dynamic obstacle is usually made for ease of calculation. i Choosing the same value is not feasible in actual navigation environments. This is because dynamic obstacles vary in size and speed, resulting in different threats posed by obstacles of different sizes and speeds. Clearly, the larger and faster the dynamic obstacle, the shorter the obstacle avoidance distance and emergency response time. In other words, larger and faster dynamic obstacles pose a greater threat, which manifests in the speed obstacle space (VO) as a larger area for the dynamic obstacle.

[0135] Therefore, the present invention defines different weights for dynamic obstacles of different sizes and speeds in the following manner:

[0136] First, calculate the spatial VO of each individual dynamic obstacle. i and speed v i The proportion of each dynamic obstacle in the total sum, i.e., the VO of each dynamic obstacle is calculated. i The space occupied by all dynamic obstacles VO i The ratio of the sum of spaces, and at the same time, the velocity v of each dynamic obstacle is calculated. i The ratio of the velocity of all dynamic obstacles to the sum of their velocities.

[0137] Then, by using the VO of each of the above dynamic obstacles i Space ratio and v i The obstacle avoidance weight λ for each dynamic obstacle is obtained by summing the corresponding speed ratios one by one and taking the average. i That is, the obstacle avoidance weight λ for each dynamic obstacle. i It is one-half of the sum of the two ratios, and the specific formula is as follows:

[0138]

[0139] The obstacle avoidance weight λ obtained through this formula is used. i The system can assign different obstacle avoidance priorities to different dynamic obstacles during navigation. Among them, dynamic obstacles with higher weights have higher priority in the obstacle avoidance strategy, and the ship will prioritize avoiding these dynamic obstacles when planning its route.

[0140] Furthermore, to facilitate quantitative analysis, this invention performs discretization and quantization on the velocity obstacle space VO of the dynamic obstacle, thereby traversing and quantizing all velocity evaluation values, and selecting the minimum value among the evaluation values ​​as the final velocity. In this embodiment, taking an obstacle ship as an example of a dynamic obstacle, the specific steps include: First, the velocity obstacle space VO of the dynamic obstacle is discretized and quantized. Specifically, a fan-shaped grid method is used for spatial discretization, which will not be elaborated here. Figure 1 As shown, the principle of the sector grid is as follows: the grid is constructed using a sector grid formed by equal-angle rays emanating from the ship's center and straight lines with equal radial step lengths. Changes in circumferential angles represent changes in heading, and changes in radial step lengths represent changes in speed. Subsequently, all quantized speeds in the feasible speed space VO are traversed, evaluation values ​​are calculated, and the minimum value among the evaluation values ​​is selected as the final speed.

[0141] This invention constructs a speed obstacle model to quantitatively analyze the relative motion relationship between the vessel and surrounding obstacles, thereby reducing the probability of collisions with dynamic or static obstacles and enhancing collision avoidance capabilities. Furthermore, based on the hazard level of dynamic obstacles, this invention dynamically assigns collision avoidance weights to dynamic obstacles with different obstacle space sizes and speed magnitudes through dynamic weighting, achieving a more intelligent obstacle avoidance strategy.

[0142] S4. Periodically run steps S1 to S3, with an operating period of ΔT. In this embodiment, the operating period ΔT is set to be executed once every 1 to 2 seconds. Through dynamic real-time calculation, the latest predicted path can be given in real time based on the positions of the ship and the target ship.

[0143] When the operating cycle reaches ΔT, the current position p of the target ship is obtained again. T And the ship's current position p o If the current position p of the target ship is obtained T And the ship's current position p o Very close, that is, when ||p T -p o ||≤θ, where θ is the preset interception threshold and is generally set to 0.1 nautical miles. At this point, the interception is considered to have achieved its purpose and the interception ends. In addition, if there is an emergency that requires the interception to be terminated, it can also be operated directly. The system will accept the function stop command based on the target ship and the interception will end.

[0144] If the current position p of the target ship is obtained T And the ship's current position p o Not similar, that is, when ||p T -p oIf ||>θ, the interception is determined to be incomplete, and steps S1 to S3 are executed. The ship's current position p is then recalculated through steps S1 to S3. o Reach the target ship's current position p T The optimal collision avoidance and interception path.

[0145] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art can make various changes or equivalent substitutions to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this invention.

Claims

1. A method for intercepting target ships based on speed barriers, characterized in that, Includes the following steps, S1. Obtain the current position p of the target ship. T Current speed v T And the ship's current position p o At the same time, determine the ship's maximum speed. and the ship's safe radius R O Among them, the safe radius R of this ship O This is the radius of the ship's largest circumscribed circle; S2. Based on a multi-iteration method, iteratively update the new position of the target ship when it encounters the current ship, until the final position p'k is obtained. T The position p'k- of the previous iteration is satisfied. 1T The relative distance between them is not greater than the set error threshold ε; S3, Based on the final position p' of the target vessel. kT In the case of multiple dynamic obstacles ahead, a speed obstacle model is constructed using the speed obstacle method to plan the optimal collision avoidance and interception path from the current vessel to the target vessel: First, assuming there are i dynamic obstacles, construct the velocity obstacle region VO for each dynamic obstacle one by one. i ; Then, based on the situation of multiple dynamic obstacles, a weighted obstacle avoidance strategy is adopted: considering the different obstacle avoidance weights of each dynamic obstacle, among the speeds v that do not fall within the speed obstacle space VO, the optimal speed v that can satisfy the ship's ability to avoid obstacles while getting as close as possible to the target ship is selected as the ship's speed v. O ; S4. Periodically run steps S1 to S3, with a running period of ΔT; If the current position p of the target ship is obtained T And the ship's current position p o If the relative distance between them is not greater than the preset interception threshold θ, the interception is determined to have achieved its purpose and the interception ends. Otherwise, continue execution and re-plan the ship's current position p. o Reach the target ship's current position p T The optimal collision avoidance and interception path.

2. The target ship interception method based on speed barrier according to claim 1, characterized in that, Step S2 includes the following specific steps: S2-1, Based on the ship's maximum speed Estimate the distance from the ship's current position p o Reach the target ship's current position p T Required direct time t arrive ; S2-2, Based on direct arrival time t arrive Calculate the new position p' of the target ship when it encounters the current ship. T ; S2-3, Iterate and update the new position of the target ship until k iterations, at which point p' is obtained. kT Satisfy ||p' kT -p' k-1T When ||≤ε, the p' obtained is... kT This is the final location of the target ship.

3. The target ship interception method based on speed barrier according to claim 2, characterized in that, In step S2-2, if there are no static obstacles in the direction of the target ship's navigation, then the new position p' of the target ship when it encounters the ship is calculated. T The steps include: Assume the target ship's speed is v T ; Then after time t arrive Afterwards, the target ship's new position p' T for: p' T =p T +v T ·t arrive 。 4. The target ship interception method based on speed barrier according to claim 2, characterized in that, In step S2-2, if there is a static obstacle in the direction of the target ship's navigation, then the new position p' of the target ship when it encounters the current ship is calculated. T The steps include: Based on the location of the static obstacle, the positions of each turning point are determined as p. r1 p r2 p r3 p r4 p r5 ...p rlast ; Assume the target ship's speed is The time required for each segment of the target ship's voyage is calculated as follows: The remaining time t after the target ship turns at the last turning point last for: t last =t arrive -t r1 -t r2 -t r3 -...-t rlast Thus, the time t is obtained. arrive Afterwards, the target ship's new position p' T for: p' T =p rlast +v T ·t last 。 5. The target ship interception method based on speed barrier according to claim 4, characterized in that, The random turning angles of the target ship at each turning point are δ1, δ2, δ3, δ4..., and the range of the random turning angle δ is the angle at which the target ship can continue to sail, and the random turning angle δ≤30°.

6. The target ship interception method based on speed barrier according to claim 1, characterized in that, In step S3, the velocity obstacle region VO of each dynamic obstacle is constructed one by one. i This includes the following specific steps: S3-1, Define the relative velocity v between the i-th dynamic obstacle and the ship. Oi :v Oi =v O -v i , where v O Represents the speed of the own ship, v i Represents the velocity of the i-th dynamic obstacle; S3-2, Construct the velocity obstacle region VO of the i-th dynamic obstacle. i : Assume the safe radius of the i-th dynamic obstacle is R. i R i Let be the radius of the largest circumcircle of the i-th dynamic obstacle, then used to calculate the velocity obstacle region VO. i The safety radius is R' i : R' i =R i +R O Then in the future time t arrive Inside, all possible ship speeds v that could lead to a collision O satisfy: ||p' T -(p O +v O ·t arrive )||<R' i Converting the above formula into a velocity space, we get all possible ship velocities v that could lead to a collision. O satisfy: ||p' T -p O -v O ·t arrive ||<R' i All ship speeds v calculated using the above formulas O The velocity obstacle region VO that constitutes the i-th dynamic obstacle i .

7. The target ship interception method based on speed barrier according to claim 1, characterized in that, In step S3, a weighted obstacle avoidance strategy is adopted when there are multiple dynamic obstacles, including the following specific steps: S3-3. Calculate the obstacle avoidance strategy under multiple dynamic obstacles and obtain the ship's speed v. O : in: VO stands for velocity obstacle space, which is the velocity obstacle area of ​​all dynamic obstacles. i A set; v g The ideal speed for intercepting the target ship; v g Size and maximum speed of the ship The same size, v g The direction is that of this ship relative to p' kT The direction; λ i The obstacle avoidance weights for each dynamic obstacle; VO i Let be the speed obstacle region of the i-th dynamic obstacle.

8. The target ship interception method based on speed barrier according to claim 7, characterized in that, In step S3-3, the obstacle avoidance weight λ of each dynamic obstacle i Defined in the following manner: First, calculate the spatial VO of each individual dynamic obstacle. i and velocity v i The percentage of all dynamic obstacles in the total; Then, by using the VO of each of the above dynamic obstacles i Space ratio and v i The obstacle avoidance weight λ for each dynamic obstacle is obtained by summing the corresponding speed ratios one by one and taking the average. i .

9. A method for intercepting a target ship based on a speed barrier according to any one of claims 7 or 8, characterized in that, In step S3-3, the velocity obstacle space VO is discretized and quantized to iterate through and quantize all the velocity evaluation values, and the minimum value among the evaluation values ​​is selected as the final velocity.

10. A method for intercepting a target ship based on a speed barrier according to claim 9, characterized in that, The discrete quantization process employs a fan-shaped grid for spatial discretization.

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