A collision risk calculation method based on relative distance

Abstract

The present invention relates to the field of ship obstacle avoidance technology and provides a method for calculating collision risk based on relative distance, comprising: setting a safe encounter distance and a dynamic range distance based on the ship's size, maneuverability, and navigation speed information; obtaining target information of targets perceived around the ship, and calculating the target's closest encounter distance, closest encounter time, and the relative distance between the ship and the target based on the target information; judging whether there is a collision risk between the ship and the target based on the closest encounter distance, the safe encounter distance, and the closest encounter time; calculating the target collision risk based on the relative distance between the ship and the target, the dynamic range distance, and the safe encounter distance; and judging whether to initiate avoidance based on the target collision risk and a risk threshold. The method of the present invention is simple and easy to implement, and can intuitively judge the degree of collision risk and initiate avoidance action in a timely manner based on the magnitude of the collision risk, thereby improving the safety of ship navigation.

Description

Technical Field

[0001] The present invention relates to the technical field of ship obstacle avoidance, and in particular to a collision risk calculation method based on relative distance. Background Art

[0002] According to navigation practice, the closest approach distance ( ) and the time of last encounter ( ) two quantities, and for 、 Scholars from various countries have done a lot of research on the relationship between vehicle speed and collision risk. Determine the degree of collision risk. and Weighted judgment of ship collision risk, and research on and On the basis of the two main factors, three factors are added: the distance between the two ships, the relative position, and the speed ratio of the ships. The safe navigation of ships involves the influence of many factors, such as human factors, environmental factors, and ship factors. These factors have a complex and compound effect on ship collision accidents, and the existing methods are 、 The method of calculating the risk of ship collision based on five factors, namely, distance, relative bearing and ship speed ratio, still has shortcomings.

[0003] Collision risk is a very important concept in both the field of ship collision avoidance and the field of marine traffic engineering. Judging whether there is a collision risk is an important basis for decision-making on collision avoidance actions. In related research, most experts and scholars generally use the collision risk degree ( ) is used to measure the presence and magnitude of collision risk, and its value range is [0,1]. This means there is no risk of collision between the two ships. It means that no matter what collision avoidance measures are taken between the two ships, a collision will occur. However, due to the ambiguity and uncertainty of the ship collision risk, there is no recognized measurement method in domestic and foreign research. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a collision risk calculation method based on relative distance, which realizes the use of dynamic range distance. Safe meeting distance 、The closest encounter distance 、Recently meet time and the danger threshold for avoidance activation , construct collision risk in segments The calculation function reflects the change in danger level at different stages. It can intuitively reflect the threat level of surrounding targets and can be used as a criterion for initiating avoidance.

[0005] The present invention provides a method for calculating collision risk based on relative distance, comprising:

[0006] S1: Set the safe encounter distance and moving distance according to the ship's size, maneuverability and sailing speed information;

[0007] S2: Obtain target information of the target perceived around the ship, and calculate the closest encounter distance, closest encounter time and relative distance between the ship and the target based on the target information;

[0008] S3: Determine whether there is a collision risk between the ship and the target based on the closest approach distance, safe approach distance, and closest approach time, and obtain the collision risk category between the ship and the target;

[0009] S4: Calculate the target collision risk based on the collision risk category, relative distance between the ship and the target, moving range, and safe encounter distance;

[0010] S5: Determine whether to initiate avoidance based on the target collision risk and the risk threshold.

[0011] According to the method for calculating collision risk based on relative distance provided by the present invention, the method further includes that in the step S3, if the closest encounter distance is less than the safe encounter distance and the closest encounter time is greater than 0, there is a collision risk between the ship and the target.

[0012] According to a method for calculating collision risk based on relative distance provided by the present invention, the method further includes: in the step S3, if the closest encounter distance is not less than the safe encounter distance, there is no collision risk between the ship and the target; if the closest encounter distance is less than the safe encounter distance and the closest encounter time is not greater than 0, there is no collision risk between the ship and the target.

[0013] According to the present invention, a method for calculating collision risk based on relative distance further includes the following steps: in step S4, if the target does not enter the distance for taking avoidance action,

[0014] If the relative distance between the ship and the target is greater than 2 times the moving distance, the collision risk of the ship is the first collision risk, which is 0;

[0015] If the relative distance between the ship and the target is greater than the moving distance and less than 2 times the moving distance, the collision risk of the ship is the second collision risk. The calculation expression of the second collision risk is:

[0016]

[0017] in, is the second collision risk, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance.

[0018] According to the present invention, a method for calculating collision risk based on relative distance further includes the following steps: in step S4, the target has entered the distance for taking avoidance action;

[0019] If the relative distance between the ship and the target is greater than 2 times the safe encounter distance and less than the moving distance, the collision risk of the ship is the third collision risk. The calculation expression of the third collision risk is:

[0020]

[0021] in, is the third collision risk, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance;

[0022] If the relative distance between the ship and the target is less than or equal to 2 times the safe encounter distance and greater than the safe encounter distance, the collision risk of the ship is the fourth collision risk. The calculation expression of the fourth collision risk is:

[0023]

[0024] in, It is the fourth collision risk level.

[0025] According to the method for calculating collision risk based on relative distance provided by the present invention, the method further includes: in step S4, if the relative distance between the ship and the target is less than the safe encounter distance, the collision risk of the ship is the fifth collision risk, and the calculation expression of the fifth collision risk is:

[0026]

[0027] in, is the fifth collision risk level, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance.

[0028] According to a method for calculating collision risk based on relative distance provided by the present invention, the following also includes that when there is no collision risk between the ship and the target, the collision risk of the ship is a sixth collision risk, and the calculation expression of the sixth collision risk is:

[0029]

[0030] in, is the sixth collision risk level, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance, The most recent meeting time.

[0031] According to a relative distance-based collision risk calculation method provided by the present invention, the target also includes a static target and a dynamic target.

[0032] According to a relative distance-based collision risk calculation method provided by the present invention, the target information also includes target position, ground speed, ground heading, relative distance, and relative orientation.

[0033] According to a method for calculating collision risk based on relative distance provided by the present invention, the calculation expression of the closest encounter distance is:

[0034]

[0035] in, For the closest encounter distance, is the relative distance between the ship and the target, is the relative angle between the ship and the target;

[0036] The calculation expression of the closest encounter time is:

[0037]

[0038] in, For the most recent meeting time, is the relative speed between the ship and the target.

[0039] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0040] The present invention provides a collision risk calculation method based on relative distance, using the dynamic range distance Safe meeting distance 、The closest encounter distance 、Recently meet time and the danger threshold for avoidance activation , construct collision risk in segments The calculation function reflects the change in danger level at different stages. It can intuitively reflect the threat level of surrounding targets and can be used as a criterion for initiating avoidance.

[0041] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is a flow chart of a method for calculating collision risk based on relative distance provided by the present invention. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described clearly and completely below. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0045] In the description of the embodiments of the present invention, it should be noted that the terms “first”, “second” and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0046] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0047] The following combination Figure 1 A collision risk calculation method based on relative distance according to the present invention is described.

[0048] A flowchart of a method for calculating collision risk based on relative distance according to an embodiment of the present invention is shown in FIG. Figure 1 As shown, including:

[0049] S1: Set the safe encounter distance and moving distance according to the ship's size, maneuverability and sailing speed information;

[0050] S2: Obtain target information of the target perceived around the ship, and calculate the closest encounter distance, closest encounter time and relative distance between the ship and the target based on the target information;

[0051] S3: Determine whether there is a collision risk between the ship and the target based on the closest approach distance, safe approach distance, and closest approach time, and obtain the collision risk category between the ship and the target;

[0052] S4: Calculate the target collision risk based on the collision risk category, relative distance between the ship and the target, moving range, and safe encounter distance;

[0053] S5: Determine whether to initiate avoidance based on the target collision risk and the risk threshold.

[0054] According to the present invention, a collision risk calculation method based on relative distance is provided, which sets a safe encounter distance based on ship size, maneuverability, and navigation speed. and the distance to take evasive action ; The purpose of this step is to set the safe encounter distance and moving distance of ships.

[0055] In a specific embodiment of the present invention, assuming that the ship is at the initial position (0, 0) and sailing in the direction of 0°, with a speed of 10 kn, the safe encounter distance is set based on the ship size, maneuverability, and sailing speed. 300m, dynamic range It is 1800m.

[0056] Furthermore, according to a collision risk calculation method based on relative distance provided by the present invention, target information of the target perceived around the ship is obtained, and the closest encounter distance of the target is calculated based on the target information. 、Recently meet time and the relative distance between the ship and the target .

[0057] Furthermore, the target information includes target position, speed over the ground, course over the ground, relative distance, and relative orientation; the obstacle is a static target or a dynamic target.

[0058] Furthermore, according to a collision risk calculation method based on relative distance provided by the present invention, the calculation expression of the closest encounter distance is:

[0059]

[0060] in, For the closest encounter distance, is the relative distance between the ship and the target, is the relative angle between the ship and the target;

[0061] The calculation expression of the closest encounter time is:

[0062]

[0063] in, For the most recent meeting time, is the relative speed between the ship and the target.

[0064] The purpose of this step is to obtain the closest encounter distance of each obstacle target and the most recent meeting time and the relative distance between the ship and the target .

[0065] In a specific embodiment of the present invention, there are two obstacles in front of the ship, a dynamic target and a static target. The dynamic target is at a relative distance of 1710m at a 3° direction from the ship and is sailing at a speed of 12kn in a direction of 185°. The static target is at a relative distance of 1150m at a 355° direction from the ship.

[0066] According to the target position, ground speed, ground course, relative distance and relative direction of the target, the dynamic target is obtained. 9m, dynamic target 156s, static target 100m, static target 230s.

[0067] Furthermore, according to a relative distance-based collision risk calculation method provided by the present invention, whether there is a collision risk is determined based on the closest encounter distance, the safe encounter distance, and the closest encounter time;

[0068] If the closest encounter distance is less than the safe encounter distance and the closest encounter time is greater than 0, the ship and the target are moving towards each other, the relative distance between the ship and the target is gradually shortening, and there is a risk of collision between the ship and the target;

[0069] If the closest encounter distance is not less than the safe encounter distance, the distance between the ship and the target is too far and there is no risk of collision between the ship and the target;

[0070] If the closest encounter distance is less than the safe encounter distance and the closest encounter time is not greater than 0, the ship and the target are moving in opposite directions, the relative distance between the ship and the target gradually increases, and there is no risk of collision between the ship and the target.

[0071] The purpose of this step is to identify the conditions under which a collision risk occurs between the ship and the target and the type of collision risk.

[0072] In a specific embodiment of the present invention, the safe encounter distance 300m, dynamic target is 9m, and the dynamic target It is 156s, so there is a risk of collision with dynamic targets;

[0073] Safe meeting distance 300m, static target is 100m, and the static target The time taken is 230s, so there is a risk of collision with static targets.

[0074] Furthermore, according to a relative distance-based collision risk calculation method provided by the present invention, the target collision risk is calculated based on the relative distance between the ship and the target, the moving range distance, and the safe encounter distance;

[0075] When the vessel and the target are moving towards each other and the target is not within the range for taking evasive action:

[0076] The relative distance between the ship and the target is greater than 2 times the dynamic range. The distance is too far and there is no collision risk. The first collision risk is 0, and there is no need to pay attention to this target.

[0077] When the relative distance between the ship and the target is greater than the dynamic range but less than 2 times the dynamic range, the target and the ship are approaching each other and there is a risk of collision. Attention should be paid to the ship. The collision risk of the ship is the second collision risk, and the calculation expression of the second collision risk is:

[0078] The calculation expression of the second collision risk is:

[0079]

[0080] in, is the second collision risk, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance.

[0081] The purpose of this step is to clarify the method of calculating the danger level at different stages of the relative distance between the ship and the target when the target has not entered the distance for taking evasive action.

[0082] Furthermore, if the relative distance between the ship and the target is greater than 2 times the safe encounter distance and less than the dynamic range, the target has entered the distance range for taking avoidance action, and avoidance action needs to be initiated to ensure the navigation safety of the ship. At this time, the collision risk of the ship is the third collision risk, and the calculation expression of the third collision risk is:

[0083]

[0084] in, is the third collision risk, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance.

[0085] When the relative distance between the ship and the target is less than or equal to 2 times the safe encounter distance and greater than the safe encounter distance, the ship and the target are close, the situation is urgent, and the probability of collision is high. At this time, the collision risk of the ship is the fourth collision risk. The calculation expression of the fourth collision risk is:

[0086]

[0087] in, It is the fourth collision risk level.

[0088] The purpose of this step is to clarify the method of calculating the danger level of the relative distance between the ship and the target at different stages when the target enters the distance for taking avoidance action and is still greater than the safe encounter distance.

[0089] Furthermore, if the relative distance between the ship and the target is less than the safe encounter distance, the ship and the target are too close, resulting in limited avoidance space if there is a collision risk, and the collision probability increases. At this time, the collision risk of the ship is the fifth collision risk, and the calculation expression of the fifth collision risk is:

[0090]

[0091] in, is the fifth collision risk level, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance.

[0092] The purpose of this step is to reduce the risk of collision when the relative distance between the ship and the target is less than the safe encounter distance.

[0093] Furthermore, if the closest encounter distance is not less than the safe encounter distance, the distance between the ship and the target is too far and there is no risk of collision between the ship and the target.

[0094] If the closest encounter distance is less than the safe encounter distance and the closest encounter time is not greater than 0, the ship and the target are moving in opposite directions, the relative distance between the ship and the target gradually increases, and there is no collision risk between the ship and the target. At this time, the collision risk of the ship is the sixth collision risk. The calculation expression of the sixth collision risk is:

[0095]

[0096] in, is the sixth collision risk level, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance, The most recent meeting time.

[0097] The purpose of this step is to make it clear that when there is no collision risk with the target, the risk level gradually decreases with increasing distance.

[0098] Danger threshold ≤0.3, preferably, the risk threshold is 0.2.

[0099] In a specific embodiment of the present invention, the safe encounter distance 300m, dynamic range The danger threshold is 1800m. is 0.2;

[0100] Dynamic Target is 9m, 156s, =1710m. Since the relative distance between the ship and the target is greater than 2 times the safe encounter distance and less than the dynamic distance, the third collision risk calculation formula is used to obtain the collision risk of the dynamic target. is 0.25;

[0101] Static target is 100m, 230s, =1150m. Since the relative distance between the ship and the target is greater than 2 times the safe encounter distance and less than the dynamic distance, the third collision risk calculation formula is used to obtain the collision risk of the static target. is 0.49;

[0102] Therefore, the static target 2 that is close to the target poses a greater threat to the current navigation status.

[0103] Furthermore, according to a relative distance-based collision risk calculation method provided by the present invention, whether to initiate avoidance is determined based on the target collision risk and a risk threshold.

[0104] If the collision risk of any target is greater than the risk threshold , then avoidance is initiated; if the collision risk of any target is not greater than the risk threshold Then continue to observe.

[0105] Exceeding the threshold also indicates that the distance for taking evasive action has been reached, so evasive action needs to be initiated.

[0106] The purpose of this step is to clarify how to use the collision risk and risk threshold Determine whether to initiate avoidance.

[0107] In a specific embodiment of the present invention, according to the risk threshold The collision risk of dynamic targets is 0.2. 0.25, the collision risk of static targets is 0.49, so the collision risk of the static target is greater than the risk threshold , the collision risk of the dynamic target is greater than the risk threshold , so immediate evasive action is required.

[0108] Through the above steps, the safe encounter distance and dynamic range distance are set according to the ship size, maneuverability and navigation speed information; when the ship is sailing along the planned route, the target information perceived around the ship is obtained in real time, and the closest encounter distance and closest encounter time of each target are calculated; based on the closest encounter distance, safe encounter distance and closest encounter time, it is judged whether there is a collision risk between the ship and the target; the target collision risk is calculated based on the relative distance between the ship and the target, the dynamic range distance and the safe encounter distance; and whether to initiate avoidance is judged based on the target collision risk and the risk threshold. In the solution of the present invention, in order to solve the problem that collision risk is difficult to measure, a collision risk calculation method based on relative distance is proposed, using the dynamic range distance Safe meeting distance 、The closest encounter distance 、Recently meet time and the danger threshold for avoidance activation The collision risk calculation function is constructed in sections to reflect the changes in risk at different stages. The method of the present invention is simple and easy to implement, and can more intuitively reflect the threat level of surrounding targets, and can be used as a criterion for initiating avoidance.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for calculating collision risk based on relative distance, characterized in that: include: S1: Set the safe encounter distance and moving distance according to the ship's size, maneuverability and sailing speed information; S2: Obtain target information of the target perceived around the ship, and calculate the closest encounter distance, closest encounter time and relative distance between the ship and the target based on the target information; S3: Determine whether there is a collision risk between the ship and the target based on the closest approach distance, safe approach distance, and closest approach time, and obtain the collision risk category between the ship and the target; The closest encounter distance is less than the safe encounter distance, and the closest encounter time is greater than 0, indicating a collision risk between the ship and the target. S4: Calculate the target collision risk based on the collision risk category, relative distance between the ship and the target, moving range, and safe encounter distance; The target is not within the range for taking evasive action, If the relative distance between the ship and the target is greater than 2 times the moving distance, the collision risk of the ship is the first collision risk, which is 0; If the relative distance between the ship and the target is greater than the moving distance and less than 2 times the moving distance, the collision risk of the ship is the second collision risk. The calculation expression of the second collision risk is: in, is the second collision risk, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance; S5: Determine whether to initiate avoidance based on the target collision risk and the risk threshold.

2. The method for calculating collision risk based on relative distance according to claim 1, characterized in that: In step S3, if the closest encounter distance is not less than the safe encounter distance, there is no risk of collision between the ship and the target; if the closest encounter distance is less than the safe encounter distance and the closest encounter time is not greater than 0, there is no risk of collision between the ship and the target.

3. The method for calculating collision risk based on relative distance according to claim 1, characterized in that: In step S4, the target has entered the distance for taking evasive action. If the relative distance between the ship and the target is greater than 2 times the safe encounter distance and less than the moving distance, the collision risk of the ship is the third collision risk. The calculation expression of the third collision risk is: in, is the third collision risk, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance; If the relative distance between the ship and the target is less than or equal to 2 times the safe encounter distance and greater than the safe encounter distance, the collision risk of the ship is the fourth collision risk. The calculation expression of the fourth collision risk is: in, It is the fourth collision risk level.

4. The method for calculating collision risk based on relative distance according to claim 1, characterized in that: In step S4, the relative distance between the ship and the target is less than the safe encounter distance, and the collision risk of the ship is the fifth collision risk. The calculation expression of the fifth collision risk is: in, is the fifth collision risk level, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance.

5. The method for calculating collision risk based on relative distance according to claim 2, characterized in that: There is no collision risk between the ship and the target. The collision risk of the ship is the sixth collision risk. The calculation expression of the sixth collision risk is: in, is the sixth collision risk level, For the closest encounter distance, For safety, we will meet at a distance. is the risk threshold, is the relative distance between the ship and the target, is the moving distance, The most recent meeting time.

6. The method for calculating collision risk based on relative distance according to claim 1, characterized in that: The targets include static targets and dynamic targets.

7. The method for calculating collision risk based on relative distance according to claim 1, characterized in that: The target information includes target position, ground speed, ground heading, relative distance, and relative direction.

8. The method for calculating collision risk based on relative distance according to claim 1, characterized in that: The calculation expression of the closest encounter distance is: in, For the closest encounter distance, is the relative distance between the ship and the target, is the relative angle between the ship and the target; The calculation expression of the closest encounter time is: in, For the most recent meeting time, is the relative speed between the ship and the target.

Images