A ship collision avoidance situation identification method

Abstract

The application discloses a ship collision avoidance situation identification method, comprising the following steps: 1) eliminating the influence of false alarm and missing alarm of other ship information; judging whether the ID of the i-th dynamic other ship is in the ship ID in the meeting situation sequence information stored in the global variable; judging whether the i-th dynamic other ship meets the passing clearance condition; calling a meeting situation identification model based on a relative side angle to re-identify the meeting situation of the i-th dynamic other ship and putting the other ship ID and heading information into the corresponding meeting sequence according to the meeting situation; judging whether it is necessary to re-plan a local collision avoidance path by a collision avoidance decision unit; thus, one round of collision avoidance situation identification is completed; and the whole local collision avoidance task is completed. The application proposes a meeting situation identification model based on a relative side angle, and the identification result is more accurate and reliable.

Description

Technical Field

[0001] This invention relates to intelligent navigation technology for ships, and more particularly to a method for recognizing a ship's collision avoidance situation. Background Technology

[0002] Local path planning technology is a core technology supporting the safe and autonomous navigation of unmanned surface vessels (USVs). The prerequisite for local path planning is a precise understanding of the overall collision avoidance situation. However, current collision avoidance systems suffer from the following problems:

[0003] Existing encounter situation identification models suffer from problems such as unreasonable and unreliable identification results and lack of coordination in collision avoidance. These models can be broadly categorized into three types: the first type is based on the bearing of the approaching vessel; the second type is based on the difference in course between the two vessels; and the third type is a comprehensive judgment model. The first type of method determines the encounter situation using only the bearing of the other vessel, employing the vague concept of "approaching vessel" to express the approaching intentions of the two vessels. This method lacks sufficient quantification of the encounter situation. The second type of method uses the difference in course between the two vessels as the basis for identification, but ignores the position of the other vessel. The third type of method comprehensively considers the bearing of the approaching vessel and the course relationship between the two vessels; some literature may further consider using TCPA>0 to quantify the concept of "approaching vessel." However, this type of method is essentially still centered on the vessel itself, and the status of the vessel and the other vessel is no longer equal in encounter situation identification, which may lead to a lack of coordination in collision avoidance between the two vessels. Furthermore, TCPA is an instantaneous value, and small and medium-sized ships are easily affected by instantaneous disturbances from wind, waves, and currents, making the identification results unreliable.

[0004] Existing methods for identifying collision avoidance situations are often one-off or time-varying. The former means that once the collision avoidance situation is identified, it remains unchanged, ignoring the possibility of other vessels significantly changing their speed or course. This makes it unsuitable for time-varying and complex encounter situations, and such methods often fail to clearly define the conditions for clearing the way. The latter contradicts Article 13, Paragraph 4 of the Maritime Code, which states that "in an overtaking situation, before clearing the way, the giving vessel cannot treat the vessel traveling in the straight as an intersecting vessel due to a change in the bearings of both vessels caused by evasive action." Furthermore, existing methods rely solely on the state of other vessels (bearing, speed, course, etc.) at a single moment, often neglecting historical data. For example, without remembering the previous course of other vessels, it is impossible to know whether they have taken significant maneuvers.

[0005] Most existing collision avoidance situation identification methods are based on the assumption that the results of sensing and identifying the status of other vessels are stable and deterministic, and rarely consider the uncertainties of the navigation environment, sensing and identification equipment and sensing and identification algorithms. However, under real sea conditions, sensing and identification often results in false alarms and missed alarms. It is necessary to eliminate the influence of false alarms and missed alarms on other vessel information, otherwise it will affect the unmanned surface vessel's judgment and grasp of the collision avoidance situation.

[0006] In view of this, the inventors, in order to address the numerous defects caused by the imperfections in the aforementioned issues, have deeply conceived and actively researched improvement solutions to develop and design this invention. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for identifying ship collision avoidance situations, addressing the deficiencies in the prior art.

[0008] The technical solution adopted by this invention to solve its technical problem is: a method for identifying a ship's collision avoidance posture, comprising the following steps:

[0009] Step 1) Eliminate the impact of false alarms and missed alarms from other vessels;

[0010] The system continuously compares the real-time received information about other vessels with the vessel IDs in the situation sequence information stored in global variables. The encounter situation sequence includes encounter sequence, crossing sequence, crossing sequence, overtaking sequence, or overtaking sequence. The real-time received information about other vessels includes their IDs, speeds, headings, and dimensions.

[0011] Delete information about other ships that exists in global variables but is not in the real-time received information;

[0012] Step 2) Initialize the dynamic other ship counting flag i = 1;

[0013] Step 3) Initialize the identification identifier K = 0;

[0014] Step 4) Determine whether the ID of the i-th dynamic other ship is in the ship IDs stored in the global variable encounter situation sequence information. If yes, proceed to step 5); otherwise, proceed to step 7.

[0015] Step 5) Determine whether the i-th dynamic other vessel meets the clearance condition. If it does, proceed to step 6); otherwise, proceed to step 8.

[0016] Step 6) Delete the ID, course, latitude and longitude and other relevant information of the other ship in the corresponding encounter situation sequence, and proceed to step 7);

[0017] Step 7): Identify identifier K=1 and proceed to step 10);

[0018] Step 8): Determine whether the change in the direction of the i-th dynamic other vessel from the recommended direction of action by the maritime rules exceeds a certain angle. If yes, return to step 6); otherwise, proceed to step 9.

[0019] Step 9): Identify identifier K=0 and proceed to step 10);

[0020] Step 10): Determine if the identification identifier K is equal to 1. If yes, proceed to step 11); otherwise, proceed to step 12.

[0021] Step 11): Call the encounter situation identification model based on relative hull angle to re-identify the encounter situation of the i-th dynamic other vessel and put the other vessel ID, heading and other information into the corresponding encounter sequence according to the encounter situation;

[0022] Step 12): Determine if the value of i is greater than or equal to the total number of dynamic other ships. If it is, it means that all dynamic other ships have been traversed and proceed to step 13); otherwise, i = i + 1 and return to step 3) to continue identifying the next dynamic other ship.

[0023] Step 13): Return the number of other vessels in each current encounter sequence to the collision avoidance decision unit, which then determines whether it is necessary to replan the local collision avoidance path; at this point, one round of collision avoidance situation identification is completed;

[0024] Step 14): Determine whether the entire local collision avoidance task has been completed. If it has been completed, then end the process; if it has not been completed, return to Step 1) to begin the next round of collision avoidance situation identification.

[0025] According to the above scheme, in step 1), the encounter sequence, crossing sequence, crossing sequence, overtaking sequence or overtaking sequence is stored by a global dynamic array variable, which saves the ID, speed, heading, latitude and longitude and size information of the corresponding other ships.

[0026] According to the above scheme, the angle in step 8) is selected as needed, and the selected value is greater than 30°.

[0027] According to the above scheme, the specific method for judgment in step 8) is as follows: retrieve the historical course of the dynamic other ship when it was judged to be the encounter situation based on the other ship ID stored in the corresponding encounter situation sequence, and compare it with the course of the other ship at the current moment.

[0028] According to the above scheme, the conditions for passing through the clearing zone in step 5) are as follows:

[0029] Let the angle of this ship relative to the other ship be B1, and the angle of the other ship relative to this ship be B. The range of the angle is (-180°, 180°], with the left being negative and the right being positive.

[0030] If the other ship ID exists in the encounter sequence, the condition for clearing the encounter situation is: B1 < -90° or B < -150°.

[0031] If the other vessel is a straight-going vessel and its ID exists in the cross-straight-going sequence, then the condition for clearing the crossing situation is: B1 < -150° or B < -150°.

[0032] If the other vessel is a straight-ahead vessel and its ID exists in the overtaking straight-ahead sequence, then the overtaking situation must be cleared if B1 < 80° or B < 150°.

[0033] If the other vessel is the one giving way, and its ID exists in the overtaking and giving way sequence, then the overtaking situation is cleared under the following conditions: B < 80° or B1 < 150°.

[0034] If the other vessel is the one giving way, and its ID exists in the cross-give sequence, then the conditions for clearing the cross-give sequence are: B < -150° or B1 < -150°, or when the other vessel's speed is faster than this vessel and B1 > 90°, or when this vessel's speed is faster and B1 < 0°.

[0035] According to the above scheme, the encounter situation identification model based on relative hull angle in step 11) is as follows:

[0036] Identify it as a situation of mutual confrontation:

[0037] A confrontation situation can only be identified when both the absolute value of the angle B1 of the ship relative to the other ship, B1|, and the absolute value of the angle B of the other ship relative to the ship, B|B, are less than the critical angle of confrontation; the critical angle of confrontation is taken as 7°.

[0038] Identified as a cross-encounter situation:

[0039] When the bow extensions of two ships intersect at a point that satisfies the following conditions;

[0040] Let X be the distance between the intersection point and the ship. oi The distance between the intersection point and his ship is X. Ti Let the speed of the ship be V. o His ship's speed is V Ti Let the time it takes for the ship to reach the intersection be t. oi =X oi / V o The time it takes for his ship to reach the intersection is t. Ti =X Ti / V Ti Then the intersection point condition must be X. oi ∈[(t Ti -120)×V o

[22224] (unit: m);

[0041] That is, if X i If the distance between the intersection point and the vessel is greater than 22224, meaning the distance is 12 nautical miles (twice the masthead light visibility distance stipulated in Rule 22 of the Maritime Code), then the two vessels are considered to be sailing nearly parallel in the same direction, and there is no risk of collision for a considerable period of time. If X i <(t) Ti -120)×V o This means that our ship arrived at the intersection point 2 minutes earlier than the other ship. (If our ship is traveling at 4 m / s, the other ship would have arrived at the intersection point 480 m after our ship had passed it. Currently, even the largest ship is less than 400 m away.) Therefore, there is no risk of collision if the two ships maintain their original course.

[0042] In addition, the hull angle relationship must also be satisfied, that is, the absolute value of the hull angle of the other ship relative to the ship B∈[7]. ° [112.5°] and X oi ∈[(t Ti -120)×V o Only when

[22224] can it be identified as a cross-flow situation.

[0043] When the absolute value of the angle of another ship relative to its own ship is B∈[-7°,-112.5°] and X oi ∈[(t Ti -120)×V o Only when

[22224] can it be identified as a situation where the road is crossing and yielding.

[0044] Identifying an overtaking situation: The critical angle for overtaking is "22.5° aft of beam" as specified in Article 13, Subsection 2 of the Maritime Code. In order to ensure that the two vessels have a clear tendency to approach each other, the other critical angle is taken as 67.5°.

[0045] A situation can only be identified as an overtaking and yielding situation when |B|>112.5° and |B1|<67.5° and the speed of the vessel is greater than that of the other vessel.

[0046] A situation of overtaking and straight-line navigation can only be identified when |B1|>112.5° and |B|<67.5° and the speed of the vessel is less than that of the other vessel.

[0047] The beneficial effects of this invention are:

[0048] This invention proposes an encounter situation identification model based on relative hull angle, which yields more accurate and reliable identification results. Attached Figure Description

[0049] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0050] Figure 1 This is a flowchart of a method according to an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] like Figure 1 As shown, a method for identifying a ship's collision avoidance posture includes the following steps:

[0053] Step 1) Eliminate the impact of false alarms and missed alarms from other vessels;

[0054] The system continuously compares the real-time received information about other vessels with the vessel IDs in the situation sequence information stored in global variables. The encounter situation sequence includes encounter sequence, crossing sequence, crossing sequence, overtaking sequence, or overtaking sequence. The real-time received information about other vessels includes their IDs, speeds, headings, and dimensions.

[0055] Delete information about other ships that exists in global variables but is not in the real-time received information;

[0056] Step 2) Initialize the dynamic other ship counting flag i = 1;

[0057] Step 3) Initialize the identification identifier K = 0;

[0058] Step 4) Determine whether the ID of the i-th dynamic other ship is in the ship IDs stored in the global variable encounter situation sequence information. If yes, proceed to step 5); otherwise, proceed to step 7.

[0059] Step 5) Determine whether the i-th dynamic other vessel meets the clearance condition. If it does, proceed to step 6); otherwise, proceed to step 8.

[0060] The conditions for clearing the way are as follows:

[0061] Let the angle of this ship relative to the other ship be B1, and the angle of the other ship relative to this ship be B. The range of the angle is (-180°, 180°], with the left being negative and the right being positive.

[0062] If the other ship ID exists in the encounter sequence, the condition for clearing the encounter situation is: B1 < -90° or B < -150°.

[0063] If the other vessel is a straight-going vessel and its ID exists in the cross-straight-going sequence, then the condition for clearing the crossing situation is: B1 < -150° or B < -150°.

[0064] If the other vessel is a straight-ahead vessel and its ID exists in the overtaking straight-ahead sequence, then the overtaking situation must be cleared if B1 < 80° or B < 150°.

[0065] If the other vessel is the one giving way, and its ID exists in the overtaking and giving way sequence, then the overtaking situation is cleared under the following conditions: B < 80° or B1 < 150°.

[0066] If the other vessel is the one giving way, and its ID exists in the cross-give sequence, then the conditions for clearing the cross-give sequence are: B < -150° or B1 < -150°, or when the other vessel's speed is faster than this vessel and B1 > 90°, or when this vessel's speed is faster and B1 < 0°.

[0067] Step 6) Delete the ID, course, latitude and longitude and other relevant information of the other ship in the corresponding encounter situation sequence, and proceed to step 7);

[0068] Step 7): Identify identifier K=1 and proceed to step 10);

[0069] Step 8): Determine whether the change in the direction of the i-th dynamic other vessel from the recommended direction of action by the maritime rules exceeds a certain angle. If yes, return to step 6); otherwise, proceed to step 9.

[0070] The "certain angle" can be selected as needed, but it is generally recommended that the value be greater than 30°, which indicates that there is a significant change in the course of other vessels, making it easy for other vessels to detect visually or with radar.

[0071] For details on the "recommended direction of action according to the Maritime Code", please refer to Articles 13, 14, 15, 16, and 17 of the Maritime Code. For example, Article 14, paragraph 1 of the Maritime Code stipulates that "when two motor vessels meet on opposite or nearly opposite courses and there is a risk of collision, each shall turn to starboard so as to pass the other on its port side." In this case, the recommended direction of action according to the Maritime Code is "turn to starboard".

[0072] The specific method for judgment in step 8) is as follows: retrieve the historical course of the other ship when the dynamic situation was judged to be the encounter situation stored in the corresponding encounter situation sequence, and compare it with the course of the other ship at the current moment.

[0073] Step 9): Identify identifier K=0 and proceed to step 10);

[0074] Step 10): Determine if the identification identifier K is equal to 1. If yes, proceed to step 11); otherwise, proceed to step 12.

[0075] Step 11): Call the encounter situation identification model based on relative hull angle to re-identify the encounter situation of the i-th dynamic other vessel and put the other vessel ID, heading and other information into the corresponding encounter sequence according to the encounter situation;

[0076] The specific encounter situation identification model based on relative hull angle in step 11) is as follows:

[0077] Encounter situation: The critical angle of hull for encounter is taken as 7°. An encounter situation can be identified only when the absolute value of the angle B1 of the ship relative to the other ship, |B1|, and the absolute value of the angle B of the other ship relative to the ship, |B|, are both less than 7°.

[0078] Crossing encounter scenario: The bow extensions of the two ships must intersect at a point that satisfies certain conditions. Let X be the distance between the intersection point and the ship itself. oi The distance between the intersection point and his ship is X. Ti Let the speed of the ship be V. o His ship's speed is V Ti Let the time it takes for the ship to reach the intersection be t. oi =X oi / Vo The time it takes for his ship to reach the intersection is t. Ti =X Ti / V Ti Then the intersection point condition must be X. i ∈[(t Ti -120)×V o ,22224] (unit m), that is, if X i If X > 22224, it is assumed that the two ships are sailing almost parallel in the same direction and there is no risk of collision for a long time to come. i <(t) Ti -120)×V o This means that our vessel arrives at the intersection point 2 minutes earlier than the other vessel, and there is no risk of collision if both vessels maintain their original course. Furthermore, the following conditions must also be met: the angle of hull relative to our vessel must be B∈[7°, 112.5°] and X... i ∈[(t Ti -120)×V o Only when

[22224] can it be identified as an intersection (the other ship is a straight-ahead vessel) situation. When the angle B” of the other ship 2 relative to this ship is ∈ [7°, 112.5°], and the intersection point P2 of the bow extension of the other ship 2 and this ship also satisfies the condition, then the other ship 2 and this ship form an intersection situation (the other ship is a straight-ahead vessel). When the absolute value of the angle B” of the other ship relative to this ship is ∈ [-7°, -112.5°] and X i ∈[(t Ti -120)×V o Only when the angle B' of other vessel 1 relative to this vessel is [-7°, -112.5°] can it be identified as an intersection (other vessel is the give-way vessel). When the angle B' of other vessel 1 relative to this vessel is [-7°, -112.5°], and the intersection point P1 of the bow extension of other vessel 1 and this vessel also satisfies the condition, then other vessel 2 and this vessel form an intersection (other vessel is the give-way vessel) situation.

[0079] Overtaking Situation: The critical angle for overtaking is determined by referring to "22.5° aft of beam" as specified in Rule 13, Subsection 2 of the Maritime Code. To ensure a clear approaching tendency between the two vessels, another critical angle is set at 67.5°. An overtaking situation (with the other vessel giving way) can only be identified if |B| > 112.5° and |B1| < 67.5°, and the vessel's speed is greater than the other vessel's speed. An overtaking situation (with the other vessel proceeding in a straight line) can only be identified if |B1| > 112.5° and |B| < 67.5°, and the vessel's speed is less than the other vessel's speed.

[0080] Ordinary encounter situation: Except for the situation of meeting head-on, overtaking, and cross encounter, no special treatment is given to avoid collisions with other ships of this type.

[0081] Step 12): Determine if the value of i is greater than or equal to the total number of dynamic other ships. If it is, it means that all dynamic other ships have been traversed and proceed to step 13); otherwise, i = i + 1 and return to step 3) to continue identifying the next dynamic other ship.

[0082] Step 13): Return the number of other vessels in each current encounter sequence to the collision avoidance decision unit, which then determines whether it is necessary to replan the local collision avoidance path; at this point, one round of collision avoidance situation identification is completed;

[0083] Step 14): Determine whether the entire local collision avoidance task has been completed. If it has been completed, then end the process; if it has not been completed, return to Step 1) to begin the next round of collision avoidance situation identification.

[0084] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for identifying a ship's collision avoidance posture, characterized in that, Includes the following steps: Step 1) Eliminate the impact of false alarms and missed alarms from other vessels; The system compares the real-time received information about other vessels with the vessel IDs in the situation sequence information stored in the global variables. The situation sequences stored in the global variables include encounter sequences, crossing and yielding sequences, crossing and straight-ahead sequences, overtaking and straight-ahead sequences, or overtaking and yielding sequences. The real-time received information about other vessels includes the vessel ID, speed, heading, and size. Delete information about other ships that exists in global variables but is not in the real-time received information; Step 2) Initialize the dynamic other ship counter flag i=1; Step 3) Initialize the identification identifier K=0; Step 4) Determine if the ID of the i-th dynamic other ship is in the ship IDs stored in the global variable encounter situation sequence information. If yes, proceed to step 5); otherwise, proceed to step 7). Step 5) Determine if the i-th dynamic other vessel meets the clearance condition. If it does, proceed to step 6; otherwise, proceed to step 8. Step 6) Delete the relevant information, including the ID, course, latitude and longitude of the other ship, from the corresponding encounter sequence, and proceed to Step 7). Step 7) Identify identifier K=1 and proceed to step 10). Step 8) Determine whether the change in the opposite direction of the i-th dynamic other vessel's course to the recommended course of action by the maritime rules exceeds the set angle; if so, return to step 6). Otherwise proceed to step 9). Step 9) Identify identifier K=0 and proceed to step 10). Step 10) Determine if the identification identifier K is equal to 1. If yes, proceed to step 11). Otherwise proceed to step 12). Step 11) Call the encounter situation identification model based on relative hull angle to re-identify the encounter situation of the i-th dynamic other vessel and put the other vessel ID and heading information into the corresponding encounter sequence according to the encounter situation; Step 12) Determine if the value of i is greater than or equal to the total number of dynamic other ships. If it is, it means that all dynamic other ships have been traversed and proceed to step 13); otherwise, increment the value of i by 1 and return to step 3) to continue identifying the next dynamic other ship. Step 13) Return the number of other vessels in each current encounter sequence to the collision avoidance decision unit, which then determines whether it is necessary to replan the local collision avoidance path; at this point, one round of collision avoidance situation identification is completed; Step 14) Determine whether the entire local collision avoidance task has been completed. If it has been completed, then end the process; if it has not been completed, return to Step 1) to start the next round of collision avoidance situation identification.

2. The ship collision situation recognition method according to claim 1, characterized in that, In step 1), the encounter sequence, crossing sequence, crossing sequence, overtaking sequence, or overtaking sequence is stored in a global dynamic array variable, which stores the ID, speed, heading, latitude and longitude, and size information of the corresponding other vessel.

3. The ship collision situation recognition method according to claim 1, characterized in that, The set angle value in step 8) is greater than 30°.

4. The ship collision situation recognition method according to claim 1, characterized in that, The specific method for judgment in step 8) is as follows: retrieve the historical course of the dynamic other ship when it was judged to be in the encounter situation based on the other ship ID in the corresponding encounter situation sequence, and compare it with the course of the other ship at the current moment.

5. The ship collision situation recognition method according to claim 1, characterized in that, The conditions for passing through the clearing zone in step 5) are as follows: Let the angle of this ship relative to the other ship be B1, and the angle of the other ship relative to this ship be B. The range of the angle is (-180°, 180°). If his ship ID exists in the encounter sequence, the passing clearance condition for the encounter situation is: or ; If the other vessel is a direct-flow vessel and its ID exists in the cross-direct-flow sequence, then the condition for clearing the vessel in the cross-situation is: or ; If the other ship is a SOG ship, the other ship ID exists in the overtaking SOG sequence, the overtaking situation passes the clear condition if: or ; If the other vessel is the one giving way, and its ID exists in the overtaking and giving way sequence, then the condition for clearing the overtaking situation is: or ; If the other vessel is the one giving way, and its ID exists in the intersection giving way sequence, then the condition for clearing the intersection situation is: or Or when another ship is faster than ours and Or the ship is relatively fast and .

6. The ship collision avoidance posture identification method according to claim 1, characterized in that, The encounter situation identification model based on relative hull angle in step 11) is as follows: Identify it as a situation of mutual confrontation: When the absolute value of the angle B1 of this vessel relative to another vessel The absolute value of the angle B of the ship relative to other ships. When both angles are less than the critical angle for a confrontation, the situation is identified as a confrontation. Identified as a cross-encounter situation: When the bow extensions of two ships intersect at a point that satisfies the following conditions; Let the distance between the intersection point and the ship be... The distance between the intersection and other ships is Assume the ship's speed is... The speed of his ship was Let the time when the ship arrives at the intersection be... The time his ship arrived at the intersection was Then the intersection condition must be: ; The side angle relationship also needs to be met, that is, when the absolute value of the side angle of the other ship relative to the own ship and is identified as a crossing straight-ahead situation; When the absolute value of the angle between his ship and the side of the own ship is less than 90 degrees and , the intersection situation is identified. Identify it as a situation of overtaking: When and and the ship's speed is greater than the other ship's speed, the overtaking yielding situation is identified. When And And the ship's speed is less than the other ship's speed, the overtaking situation is identified.

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