Ship monitoring system, ship monitoring method, information processing device, and program

Abstract

[Problem] To provide a vessel monitoring system with which it is possible to visualize the risk of a collision or a close approach along a width direction that is orthogonal to a course direction of another vessel. [Solution] This vessel monitoring system comprises: a first data generation unit that generates first vessel data representing the position and the speed of a first vessel; a second data generation unit that generates second vessel data representing the position and the speed of a second vessel; a risk area specification unit which, on the basis of the estimated position of the first vessel and the estimated position of the second vessel, which are estimated from the first vessel data and the second vessel data, at various points in time when the first vessel changes course in an arbitrary direction and will presumably cut across a predicted course of the second vessel, specifies a risk area, within predicted courses for the second vessel, in which a risk value representing the risk of the first vessel and the second vessel colliding is at or above a threshold value; and a display unit that displays a polygonal Obstacle Zone by Target (OZT) having, as vertexes, at least the back end and the front end of the risk area and a point representing the first vessel in a position corresponding to the back end of the risk area.

Description

[Technical Field]

[0001] The present invention relates to a ship monitoring system, a ship monitoring method, an information processing device, and a program. [Background technology]

[0002] Conventionally, there are various methods for assessing the risk of collision between ships. For example, Non-Patent Document 1 discloses a method for displaying an OZT (Obstacle Zone by Target). In this method, a circular OZT with a radius equal to a predetermined safe separation distance is displayed on the predicted course of the other ship. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Imazu, Junji Fukuto, Masayoshi Numano, "About the Obstruction Zone and its Display by Other Vessels", Journal of the Japan Institute of Navigation, 2002, Vol. 107, pp. 191-197 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional methods for displaying OZTs, multiple circular OZTs are displayed in a row along the predicted course of other ships, but because they only have a certain width in the width direction perpendicular to the predicted course, it is difficult for users to grasp the risk of collision or approach in the width direction.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its main purpose is to provide a ship monitoring system, a ship monitoring method, an information processing device, and a program that can visualize the risk of collision or approach in the width direction perpendicular to the course direction of another ship. [Means for solving the problem]

[0006] In order to solve the above problem, one embodiment of the ship monitoring system of the present invention comprises a first data generation unit that generates first ship data representing the position and speed of a first ship; a second data generation unit that generates second ship data representing the position and speed of a second ship; a risk range identification unit that identifies a risk range within the predicted course of the second ship where a risk value representing the risk of collision between the first ship and the second ship is greater than or equal to a threshold value based on the position of the first ship and the position of the second ship at each point in time predicted from the first ship data and the second ship data when assuming that the first ship changes course in an arbitrary direction and crosses the predicted course of the second ship; and a display unit that displays a polygonal OZT whose vertices are at least the rear and front ends of the risk range and a representative point of the first ship located at a position corresponding to the rear end of the risk range.

[0007] In another aspect of the ship monitoring method of the present invention, a first data generation unit generates first ship data representing the position and speed of a first ship, and a second data generation unit generates second ship data representing the position and speed of a second ship.Based on the positions of the first ship and the second ship at each point in time predicted from the first ship data and the second ship data when assuming that the first ship changes course in an arbitrary direction and crosses the predicted course of the second ship, a risk range is identified within the predicted course of the second ship in which a risk value representing the risk of collision between the first ship and the second ship is greater than or equal to a threshold, and a polygonal OZT having at least vertices at the rear and front ends of the risk range and a representative point of the first ship located at a position corresponding to the rear end of the risk range is displayed on a display unit.

[0008] In addition, another aspect of an information processing device of the present invention includes a risk range identification unit that identifies a risk range within the predicted course of the second vessel in which a risk value representing the risk of collision between the first vessel and the second vessel is greater than or equal to a threshold value, based on the position of the first vessel and the position of the second vessel at each point in time predicted from first vessel data representing the position and speed of the first vessel and second vessel data representing the position and speed of the second vessel, assuming that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel; and a display control unit that displays on a display unit a polygonal OZT having at least the aft and front ends of the risk range and a representative point of the first vessel located at a position corresponding to the aft end of the risk range.

[0009] In addition, another aspect of the program of the present invention causes a computer to identify a risk range within the predicted course of the second vessel in which a risk value representing the risk of collision between the first vessel and the second vessel is equal to or greater than a threshold, based on the positions of the first vessel and the second vessel at each point in time predicted from first vessel data representing the position and speed of the first vessel and second vessel data representing the position and speed of the second vessel, when it is assumed that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel; and display on a display unit a polygonal OZT having at least the aft and front ends of the risk range and a representative point of the first vessel located at a position corresponding to the aft end of the risk range as vertices. [Effects of the Invention]

[0010] According to the present invention, it is possible to visualize the risk of collision or approach in the width direction perpendicular to the course direction of another ship. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an example of the configuration of a vessel monitoring system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a other ship management database. [Figure 3] FIG. 10 is a diagram showing a display example of a conventional OZT. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of an information processing device according to an embodiment. [Figure 5] FIG. 10 is a diagram for explaining size data. [Figure 6] FIG. 10 is a diagram for explaining size data. [Figure 7] FIG. 10 is a diagram illustrating an example of a procedure of a process executed by a risk range identification unit. [Figure 8A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 8B] FIG. 10 is a diagram showing a display example of an OZT. [Figure 9] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 10] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 11] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 12] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 13] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 14] FIG. 10 is a diagram showing a display example of an OZT. [Figure 15A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 15B] FIG. 10 is a diagram showing a display example of an OZT. [Figure 15C] FIG. 10 is a diagram showing a display example of an OZT. [Figure 16A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 16B] FIG. 10 is a diagram showing a display example of an OZT. [Figure 16C] FIG. 10 is a diagram showing a display example of an OZT. [Figure 17] FIG. 10 is a diagram showing a display example of an OZT. [Figure 18A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 18B] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 18C] FIG. 10 is a diagram showing a display example of an OZT. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] Fig. 1 is a block diagram showing an example of the configuration of a ship monitoring system 100 according to an embodiment. A ship monitoring method according to an embodiment is realized in the ship monitoring system 100. The ship monitoring system 100 is a system that is installed on a ship and monitors ships present in the vicinity.

[0014] The vessel equipped with the vessel monitoring system 100 is an example of a first vessel, and will be referred to as the "own vessel" in the following description. The vessels present around the own vessel are examples of second vessels, and will be referred to as the "other vessels" in the following description.

[0015] In the following description, "speed" is a vector quantity representing speed and direction (so-called ship speed vector), and "velocity" is a scalar quantity.

[0016] The vessel monitoring system 100 includes an information processing device 1, a display unit 2, a radar 3, an AIS 4, a GNSS receiver 5, a gyrocompass 6, an ECDIS 7, and an alarm unit 8. These devices are connected to a network N such as a LAN, and are capable of network communication with each other.

[0017] The information processing device 1 is a computer including a CPU, RAM, ROM, nonvolatile memory, an input / output interface, etc. The CPU of the information processing device 1 executes information processing in accordance with a program loaded from the ROM or nonvolatile memory to the RAM.

[0018] The program may be supplied via an information storage medium such as an optical disk or a memory card, or may be supplied via a communication network such as the Internet or a LAN.

[0019] The display unit 2 is, for example, a display device with a touch sensor. The touch sensor detects a position on the screen pointed to by a finger or the like. The pointed position may be input by a trackball or the like, instead of the touch sensor.

[0020] The radar 3 emits radio waves around the ship and receives the reflected waves, generating echo data based on the received signals. The radar 3 also identifies targets from the echo data and generates target tracking data (TT data) that indicate the position and speed of the targets.

[0021] The AIS (Automatic Identification System) 4 receives AIS data from other ships around the ship or from land-based control. Instead of AIS, a VDES (VHF Data Exchange System) may also be used. The AIS data includes the position and speed of other ships.

[0022] The GNSS receiver 5 detects the ship's position based on radio waves received from the GNSS (Global Navigation Satellite System). The gyrocompass 6 detects the ship's heading. A GPS compass or a magnetic compass may be used instead of a gyrocompass.

[0023] An ECDIS (Electronic Chart Display and Information System) 7 acquires the ship's position from the GNSS receiver 5 and displays the ship's position on an electronic chart. The ECDIS 7 also displays the ship's planned route on the electronic chart. A GNSS plotter may be used instead of an ECDIS.

[0024] The warning unit 8 issues a warning when there is a risk of collision between the ship and another ship. The warning unit 8 may issue a warning by display, sound, or light, for example. A warning by display may be issued by the display unit 2. In other words, the display unit 2 may also function as the warning unit 8.

[0025] In this embodiment, the information processing device 1 is an independent device, but is not limited to this and may be integrated with another device such as the ECDIS 7. In other words, the functional units of the information processing device 1 may be realized by another device such as the ECDIS 7.

[0026] Furthermore, the display unit 2 is also an independent device, but is not limited to this. A display unit of another device such as the ECDIS 7 may be used as the display unit 2 that displays the image generated by the information processing device 1.

[0027] In this embodiment, the combination of the GNSS receiver 5 and the ECDIS 7 is an example of a first data generator, which generates ship data indicating the ship's position and speed. Specifically, the GNSS receiver 5 detects the ship's position, and the ECDIS 7 detects the ship's speed from changes in the ship's position over time.

[0028] However, the speed of the ship may be detected based on the direction of the ship detected by the gyrocompass 6 and the speed of the ship detected by a ship's speedometer (not shown).

[0029] The radar 3 or the AIS 4 is an example of a second data generator, and generates other ship data indicating the position and speed of other ships. Specifically, the TT data generated by the radar 3 corresponds to other ship data. The AIS data generated by the AIS 4 also corresponds to other ship data.

[0030] 2 is a diagram showing an example of the other ship management database constructed in the memory of the information processing device 1. Other ship data generated by the radar 3 or the AIS 4 is registered in the other ship management database.

[0031] The other ship management database includes fields such as "other ship identifier," "position," "speed," and "direction." The positions and directions of other ships detected by radar 3 are converted into the same coordinate system as GNSS.

[0032] Figure 3 shows an example of a conventional OZT display. An OZT (Obstacle Zone by Target) is a zone in which the navigation of a ship may be obstructed by other ships, and is displayed on the predicted course of other ships.

[0033] In the conventional method of displaying OZT, multiple circular OZTs are displayed in a series within the range of the other ship's predicted course where the risk of collision is high, making it easy for users to grasp the risk of collision or approach along the course. However, in the width direction perpendicular to the course direction, the width of the OZT is constant, making it difficult for users to grasp the risk of collision or approach along the width direction.

[0034] The example in Figure 3 shows a situation in which a ship joins an area where many other ships are sailing. According to this, if the ship takes Route A, it appears that there is sufficient space, but in reality, other ships are approaching on both the starboard and port sides, causing the ship's operator to feel nervous. On the other hand, if the ship takes Route B, there are symbols of other ships along the way, so at first glance it appears that there is not enough space, but in reality, other ships are not approaching as easily as in the case of Route A, and the ship's operator feels less nervous.

[0035] Therefore, in this embodiment, as described below, the risk of collision or approach in the width direction perpendicular to the course direction of the other ship is visualized by displaying a polygonal OZT that takes into account the relative positions of the own ship and the other ship at the time of approach.

[0036] 4 is a diagram showing an example of the configuration of an information processing device 1 according to an embodiment, which realizes the ship monitoring method according to the embodiment. The information processing device 1 includes a risk area identification unit 11, a display control unit 12, and a size data storage unit 13.

[0037] The risk range identification unit 11 and the display control unit 12 are realized by the CPU of the information processing device 1 executing information processing according to a program. The size data holding unit 13 is constructed in the memory of the information processing device 1.

[0038] The risk range identification unit 11 identifies a risk range L within the predicted course of the other ship where the risk value of a collision between the own ship and the other ship is greater than or equal to a threshold value, based on the position of the own ship and the position of the other ship at each time predicted from the own ship data and the other ship data, assuming that the own ship changes course in an arbitrary direction and crosses the predicted course of the other ship (see Figure 8A).

[0039] The display control unit 12 displays on the display unit 2 a rectangular OZT whose vertices are the aft end LR and forward end LF of the risk range L identified by the risk range identification unit 11, the ship's representative point SF located at a position corresponding to the aft end LR, and the ship's representative point SR located at a position corresponding to the forward end LF (see Figure 8B).

[0040] 5 and 6 are diagrams for explaining the size data of the ship itself stored in the size data storage unit 13. The size data includes the lengths L1, L2 of the ship area S occupied by the ship itself and the lengths PL1, PL2 of the warning area P set around the ship itself.

[0041] The ship area S occupied by the ship is an area that represents the physical size of the ship. In this embodiment, the ship area S of the ship is represented by a line segment from the front end to the rear end of the ship. Length L1 is the length from the ship's reference position RP to the front end of the ship, and length L2 is the length from the ship's reference position RP to the rear end of the ship. The ship's reference position RP corresponds to the antenna position of the GNSS receiver 5 (see Figure 1).

[0042] A collision is considered to occur when another ship is present within the ship area S of the own ship. As shown in Figure 6, within the ship area S of the own ship, the risk value is set to the maximum of 1.

[0043] The surveillance area P set around the ship is set in front of and behind the ship. In this embodiment, the surveillance area P of the ship is represented by a line segment extending forward from the front end of the ship and a line segment extending rearward from the rear end of the ship. Length PL1 is the length from the front end of the ship to the front end of the surveillance area P, and length PL2 is the length from the rear end of the ship to the rear end of the surveillance area P.

[0044] It is noted that the warning area P does not have to be set behind the ship. That is, the length PL2 may be 0. It is also noted that the warning area P does not have to be set ahead of the ship. That is, the length PL1 may be 0.

[0045] The alert area P is set according to the area where the ship operator feels that the intrusion of other ships is psychologically undesirable, even though physical contact with other ships does not occur. The alert area P can be likened to a personal space where people feel uncomfortable when others get close.

[0046] In this embodiment, as shown in Figure 6(a), the risk value in the alert area P is set to the maximum of 1, just like in the ship area S. However, as shown in Figure 6(b), the risk value in the alert area P may be set to gradually decrease the further away from the ship.

[0047] In this embodiment, the ship's own ship area S and the surveillance area P are represented by lines in the fore-and-aft direction, but this is not limited to this. The widthwise length can also be added, and the ship's own ship area S and surveillance area P can be represented as a rectangular area, or as a line cross type in which a fore-and-aft line segment intersects with a widthwise line segment, or as a bumper shape such as an ellipse, oval, or egg shape.

[0048] For other ships, as with the own ship, a ship area occupied by the other ship and a warning area set around the other ship are set. The fore-and-aft length of the other ship may be, for example, the ship length contained in the AIS data, or a predetermined length according to the ship type contained in the AIS data. Alternatively, the fore-and-aft length of the other ship may be estimated, for example, from echo data from the radar 3. The reference position of the other ship is set to a predetermined position, such as the center of the ship area of the other ship.

[0049] Fig. 7 is a diagram showing an example of a specific processing procedure executed by the risk range identification unit 11. The information processing device 1 executes the processing shown in the figure in accordance with a program, thereby functioning as the risk range identification unit 11. Fig. 8A and Fig. 8B are diagrams showing an example of calculation and display of OZT.

[0050] First, the risk area identification unit 11 acquires own ship data (S11), and calculates the predicted position of the own ship at each time point based on the acquired own ship data (S12).

[0051] Specifically, the ship's predicted position is calculated under the assumption that the ship will maintain its speed and change course in any direction from its current position. In other words, the magnitude of the ship's speed vector is constant, while the direction of the ship's speed vector is assumed to change course in any direction at a reference point in time, and then continue sailing in a constant direction from the ship's position at the reference point in time. Therefore, the ship's predicted position at each point in time exists on concentric circles centered on the ship's position at the reference point in time. The radius of the circle is expressed as the product of the elapsed time from the reference point in time and the magnitude of the ship's speed vector.

[0052] The predicted position of the ship at each time point is represented by a plurality of discrete concentric circles calculated for each of the plurality of discrete time points. Alternatively, the predicted position of the ship at each time point may be represented by a circular formula including the elapsed time from a reference time point (details will be described later).

[0053] In this embodiment, the predicted position of the ship is calculated under the assumption that the ship's speed is constant. However, this is not limiting and the ship's speed may be treated as a variable that changes over time. In other words, the ship's speed does not need to be constant as long as the predicted position of the ship is calculated based on the elapsed time from a reference point in time. For example, the ship's speed may gradually increase or decrease over time.

[0054] Next, the risk area identification unit 11 acquires other ship data (S13), and calculates the predicted positions of other ships at each time point based on the acquired other ship data (S14).

[0055] Specifically, the predicted position of the other ship is calculated under the assumption that the other ship will maintain its current speed. In other words, it is assumed that the magnitude and direction of the other ship's speed vector are constant and that the other ship will continue to move from its position at the reference point in time. Therefore, the predicted position of the other ship at each point in time exists on a straight line extending the other ship's speed vector and passing through the other ship's position at the reference point in time.

[0056] The predicted position of the other ship at each time point is represented by a plurality of discrete points arranged on a line, calculated for each of a plurality of discrete times. Alternatively, the predicted position of the other ship at each time point may be represented by a linear function passing through the position of the other ship at a reference time point (details will be described later).

[0057] In this embodiment, the predicted position of the other ship is calculated under the assumption that the speed of the other ship is constant. However, this is not limited to this, and at least one of the speed and direction of the other ship may be treated as a variable that changes with time. In other words, as long as the predicted position of the other ship is calculated according to the elapsed time from a reference point in time, the speed of the other ship does not have to be constant. For example, the speed of the other ship may gradually increase or decrease over time. Furthermore, the other ship may change course in a predetermined direction or turn at a predetermined ROT (Rate of Turn).

[0058] Next, the risk area identification unit 11 calculates the separation distance between the predicted position of the ship and the predicted positions of the other ships at each time point (S15). The separation distance is expressed as the distance between a point representing the predicted position of the ship and a point representing the predicted position of the other ships.

[0059] As described above, the predicted position of the ship at a certain point in time is represented by a circle, so the risk range identification unit 11 selects the position closest to the predicted position of the other ship at the same time from the circle representing the ship's predicted position at a certain point in time and calculates the separation distance.

[0060] Next, the risk range identification unit 11 acquires size data from the size data storage unit 13 (S16), and calculates a risk value representing the risk of collision between the ship and the other ship based on the separation distance and the size data (S17).

[0061] In the example of Figure 8A, the risk area identification unit 11 sets the ship's ship area S and warning area P using the ship's size data (see Figures 5 and 6), and determines whether the ship's ship area S or warning area P contains a point representing the predicted position of another ship.

[0062] For example, when the predicted position of the ship is ahead of the predicted course of the other ship, if the separation distance is equal to or less than the distance L1 from the ship's reference position RP to the front end of the ship area S, it is determined that the predicted position of the other ship is included in the ship's ship area S. Also, if the separation distance is greater than distance L1 and equal to or less than the distance L1 + PL1 from the ship's reference position RP to the front end of the warning area P, it is determined that the predicted position of the other ship is included in the ship's warning area P.

[0063] On the other hand, when the predicted position of the ship is behind the predicted course of the other ship, if the separation distance is equal to or less than the distance L2 from the ship's reference position RP to the aft end of the ship area S, it is determined that the predicted position of the other ship is included in the ship's ship area S. Also, if the separation distance is greater than distance L2 and equal to or less than the distance L2 + PL2 from the ship's reference position RP to the aft end of the warning area P, it is determined that the predicted position of the other ship is included in the ship's warning area P.

[0064] Whether the predicted position of the ship is ahead of or behind the predicted course of the other ship can be determined by the positive or negative sign of the separation distance.

[0065] In this embodiment, the distance between the point representing the predicted position of the own ship and the point representing the predicted position of the other ship was calculated, but when setting the ship area BS or warning area BP of the other ship as shown in Figures 10 and 11, the distance between the point representing the predicted position of the own ship and the front or rear end of the ship area BS or warning area BP of the other ship may also be calculated.

[0066] The risk range identification unit 11 sets the risk value to the maximum of 1 if a point representing the predicted position of another ship is included within the ship area S or warning area P of the own ship, and sets the risk value to the minimum of 0 if it is not included (see Figure 6(a)).The threshold is set between 0 and 1, and if a point representing the predicted position of another ship is included within the ship area S or warning area P of the own ship, the risk value will be greater than or equal to the threshold.

[0067] Alternatively, the risk value in the alert area P may be set to gradually decrease the further away from the own ship (see Figure 6(b)). In this case, if a point representing the predicted position of another ship is included within the own ship's alert area P and the other ship approaches the own ship's ship area S to a certain extent, the risk value will be above the threshold.

[0068] The calculation by the risk range identification unit 11 may be performed as follows. Here, an example will be described in which the position where the front end of the ship area of the own ship and the rear end of the ship area of the other ship meet is calculated.

[0069] As shown in Figure 9, the initial position of the ship at t = 0 (i.e., the current position of the ship) is set to the origin (0,0) of the xy plane. Also, the velocity vector of the ship is V o In addition, the length from the reference position of the ship to the front end is L of (Equivalent to L1 in Figure 4). Assuming that the ship can instantly change course 360 degrees from its current position and sail at a constant speed, the position of the front end of the ship's area after time t has elapsed is the radius V o t+L of It is expressed as the circumference of a circle.

[0070] On the other hand, the initial position of the other ship at t = 0 (i.e., the current position of the other ship) is (x, y) on the xy plane. Also, the velocity vector of the own ship is V t Also, the length from the reference position of the other ship to the rear end is L tb Assuming that the other ship continues sailing from its current position while maintaining both a constant course and speed, the position CP of the aft end of the ship area of the other ship after the passage of time t is expressed by the following formula 1. Here, V tx is V t is the x component of V ty is V t is the y component of

[0071]

number

[0072] Here, when the forward end of the ship area of the own ship and the aft end of the ship area of the other ship come into contact, it means that the forward end of the ship area of the own ship is within the radius V o t+L of Since the position CP of the aft end of the ship area of the other ship is located on the circumference of the circle, the following formula 2 holds.

[0073]

number

[0074] The time t at which the forward end of the ship area of the own ship and the aft end of the ship area of the other ship come into contact can be calculated by solving this equation 2. Furthermore, by substituting the calculated time t into the above equation 1, the position at which the forward end of the ship area of the own ship and the aft end of the ship area of the other ship come into contact can be calculated.

[0075] Here, we have explained how to calculate the position where the forward end of the ship's own ship's ship area and the aft end of the other ship's ship area abut, but similar calculations can also be made in other cases, such as when the forward end of the ship's own ship's surveillance area P abuts the aft end of the other ship's ship area BS as shown in Figure 10, or when the forward end of the ship's surveillance area P abuts the aft end of the other ship's surveillance area BP as shown in Figure 11.

[0076] Returning to the explanation of Figure 7, the risk range identification unit 11 identifies a risk range L in which the risk value calculated in S17 above is equal to or greater than a threshold (S18), and identifies the aft end LR and forward end LF of the risk range L, a representative point SF of the ship located at a position corresponding to the aft end LR, and a representative point SR of the ship located at a position corresponding to the forward end LF (S19). The fore-and-aft direction of the risk range L corresponds to the fore-and-aft direction of the other ship.

[0077] As described above, in this embodiment, the risk value is greater than or equal to the threshold value when a point representing the predicted position of another ship is included within the ship area S or alert area P of the ship itself, so as shown in Figure 8A, the rear end LR of the risk area L is the position where the front end of the alert area P of the ship itself abuts the point representing the position of the other ship. Also, the front end LF of the risk area L is the position where the rear end of the alert area P of the ship itself abuts the point representing the position of the other ship.

[0078] Furthermore, the representative point SF of the ship located at a position corresponding to the aft end LR of the risk range L is the forward end of the ship's ship area S. Specifically, the position of the ship corresponding to the aft end LR of the risk range L is the position of the ship when the forward end of the ship's warning area P is located at the aft end LR of the risk range L. The representative point SF of the ship is not limited to the forward end of the ship's ship area S, but may also be the reference position RP (see Figure 5), the aft end of the ship's ship area S, or the aft end of the ship's warning area P, etc.

[0079] Furthermore, the representative point SF of the ship located at a position corresponding to the forward end LF of the risk range L is the aft end of the ship's ship area S. Specifically, the position of the ship corresponding to the forward end LF of the risk range L is the position of the ship when the aft end of the ship's warning area P is located at the forward end LF of the risk range L. The representative point SF of the ship is not limited to the aft end of the ship's ship area S, but may also be the reference position RP (see Figure 5), the forward end of the ship's ship area S, or the forward end of the ship's warning area P, etc.

[0080] The risk area identification unit 11 outputs the positions of the aft end LR and front end LF of the risk area L, the representative point SF of the ship located at the position corresponding to the aft end LR, and the representative point SR of the ship located at the position corresponding to the front end LF as the vertices of the OZT to the display control unit 12, and ends the processing. Note that if there are multiple other ships, the processing of S13 to S19 is executed for each of the multiple other ships.

[0081] In the example of Figure 8B, the display control unit 12 displays a rectangular OZT on the screen of the display unit 2, with vertices at the aft end LR and front end LF of the risk range L identified by the risk range identification unit 11, the ship's representative point SF located at a position corresponding to the aft end LR, and the ship's representative point SR located at a position corresponding to the front end LF. The corners of the OZT may be rounded.

[0082] As a result, the OZT does not have a fixed width, but rather has a shape that protrudes towards the approaching ship at both the front and rear of the risk area L.

[0083] Specifically, by setting the representative point SF of the ship, which is located at a position corresponding to the aft end LR of the risk range L, as the vertex of the OZT, the OZT will extend toward the predicted position of the ship at the rear of the risk range L. On the other hand, by setting the representative point SF of the ship, which is located at a position corresponding to the forward end LF of the risk range L, as the vertex of the OZT, the OZT will extend toward the predicted position of the ship at the front of the risk range L.

[0084] By displaying an OZT of this shape, it is possible to visualize the risk of collision or approach in the width direction, which is perpendicular to the course of other ships.

[0085] In addition to the above example, the risk area identification unit 11 may determine whether the ship's ship area S or surveillance area P overlaps with the ship area BS of another ship, as shown in Figure 10. In this example, the aft end LR of the risk area L is the position where the forward end of the ship's surveillance area P abuts the aft end of the ship area BS of the other ship. The forward end LF of the risk area L is the position where the aft end of the ship's surveillance area P abuts the forward end of the ship area BS of the other ship.

[0086] The risk area identification unit 11 may also determine whether the ship's own ship's ship area S or surveillance area P overlaps with the ship's ship area BS or surveillance area BP of another ship, as shown in Figure 11. In this example, the rear end LR of the risk area L is the position where the front end of the ship's surveillance area P abuts the rear end of the other ship's surveillance area BP. The front end LF of the risk area L is the position where the rear end of the ship's surveillance area P abuts the front end of the other ship's surveillance area BP.

[0087] In addition, the risk area identification unit 11 may determine whether the ship area S of the own ship overlaps with a point representing the position of another ship, the ship area BS, or the warning area BP, without setting the ship's warning area P. In addition, the risk area identification unit 11 may determine whether the point representing the ship's position overlaps with a point representing the position of another ship, the ship area BS, or the warning area BP, without setting the ship area S and warning area P of the own ship.

[0088] The matching relationship between the own ship and the other ship is not limited to the above example, and for example, as shown in Figure 12, there may be cases where the forward end of the own ship's warning area P abuts the aft end of the other ship's ship area BS (or warning area BP) at both the forward end LF and the aft end LR of the risk area L. In this case, the representative point SF of the own ship located at a position corresponding to the forward end LF of the risk area L is the forward end of the own ship's ship area S, the reference position, the aft end of the own ship's ship area S, or the aft end of the own ship's warning area P, etc.

[0089] Also, as shown in Figure 13, when two risk areas L occur, in the risk area L farthest from other ships, the rear end LR of the risk area L may be a position where the rear end of the ship's own warning area P abuts the front end of the other ship's ship area BS (or warning area BP), and the front end LF of the risk area L may be a position where the front end of the ship's own warning area P abuts the rear end of the other ship's ship area BS (or warning area BP).

[0090] In this case, the representative point SF of the ship located at a position corresponding to the aft end LR of the risk range L is the aft end of the ship's ship area S, the reference position, the forward end of the ship's ship area S, or the forward end of the ship's warning area P. Also, the representative point SF of the ship located at a position corresponding to the forward end LF of the risk range L is the forward end of the ship's ship area S, the reference position, the aft end of the ship's ship area S, or the aft end of the ship's warning area P.

[0091] FIG. 14 shows a display example in which a rectangular OZT according to this embodiment is displayed in the same situation as the conventional example in FIG.

[0092] According to this, the rectangular OZT according to this embodiment visualizes the risk of collision or approach in the width direction perpendicular to the course direction of other ships, and as a result, when the ship takes route A, it can be seen that other ships will approach on both the port and starboard sides because there is an OZT near route A. On the other hand, when the ship takes route B, it can be seen that other ships will not approach because there is no OZT near route B, and it can be seen that other ships will not approach and the ship can navigate with ease.

[0093] In this way, by displaying a rectangular OZT that takes into account the relative positions of your ship and the other ship at the time of approach, the risk of collision or approach is visualized not only in the direction of the other ship's course, but also in the width direction perpendicular to that, making it possible to more accurately express the actual risk using OZT.

[0094] [First Modification] The first modified example will be described below. The same reference numerals are used to designate configurations that overlap with the above embodiment, and detailed descriptions thereof will be omitted. 15A and 15B are diagrams showing examples of calculation and display of OZT according to the first modified example.

[0095] As shown in Figure 15A, when the risk area identification unit 11 identifies the risk area L, it outputs the aft end LR and front end LF of the risk area L, as well as the representative point SF of the ship located at a position corresponding to the aft end LR, to the display control unit 12 as the position of the vertex of the OZT.

[0096] 15B, the display control unit 12 displays on the screen of the display unit 2 a triangular OZT with its vertices being the aft end LR and front end LF of the risk range L identified by the risk range identification unit 11, and a representative point SF of the ship located at a position corresponding to the aft end LR. The corners of the OZT may be rounded.

[0097] That is, in this modification, the representative point SR of the ship located at a position corresponding to the front end LF of the risk range L (see FIGS. 8A and 8B) is not included in the vertex of the OZT.

[0098] In the example shown, the aft end LR of the risk area L is the position where the forward end of the own ship's surveillance area P abuts the aft end of the other ship's surveillance area BS. The forward end LF of the risk area L is the position where the aft end of the own ship's vessel area S abuts the forward end of the other ship's surveillance area BP. The figure shows an example in which a surveillance area P is not set aft of the own ship or the other ship. The positions of the aft end LR and forward end LF of the risk area L are not limited to this and can be determined in various ways as described above.

[0099] Furthermore, the representative point SF of the ship, which is located at a position corresponding to the aft end LR of the risk range L, is the reference position RP of the ship (see Figure 5). However, the representative point SF of the ship is not limited to this, and may be the front end or the aft end of the ship area S of the ship.

[0100] As shown in Figure 15A, the forward end LF of the risk area L is located where the aft end of the own ship's ship area S abuts the forward end of the other ship's warning area BP, so that in front of the risk area L, the own ship is in a facing relationship, crossing ahead of the other ship. On the other hand, the aft end LR of the risk area L is located where the forward end of the own ship's warning area P abuts the aft end of the other ship's ship area BS, so that in the rear of the risk area L, the own ship is in a facing relationship, crossing behind the other ship.

[0101] As shown in Figure 15B, the OZT gradually narrows toward the forward end LF of the risk range L, and takes on a pointed shape toward the front of the risk range L, i.e., a shape that points forward of the risk range L. This allows the user, when looking at the OZT, to grasp not only the risk of collision but also the relationship between their ship and other ships before and after the OZT.

[0102] Specifically, when the vessel moves toward the pointed side of the OZT, i.e., the front side of the OZT, it can be understood that the vessel will be in a facing relationship crossing ahead of the other vessel. On the other hand, when the vessel moves toward the non-pointed side of the OZT (the side with an edge extending toward the vessel), i.e., the rear side of the OZT, it can be understood that the vessel will be in a facing relationship crossing behind the other vessel.

[0103] As shown in Fig. 15C, the display controller 12 may display an index MK in association with the front end LF of the risk range L. The index MK has a shape that points forward of the risk range L. Specifically, the index MK is, for example, mountain-shaped, and the direction is indicated by the orientation of the convex portion. However, the index MK may also be, for example, arrow-shaped or boomerang-shaped.

[0104] Furthermore, the indicator MK is displayed near the forward end LF of the risk range L, and is thereby associated with the forward end LF of the risk range L. Specifically, the indicator MK is positioned forward of the OZT on the other ship's predicted course and indicates the course direction. However, the indicator MK may be linked to the forward end LF of the risk range L, or may be connected via a lead line.

[0105] Displaying such an indicator MK makes it easier for the user to grasp the direction of travel of the other ship. Also, by displaying the indicator MK, the user can easily grasp that when the own ship moves ahead of the OZT, the own ship will be in a crossing relationship in front of the other ship.

[0106] 16A and 16B are diagrams showing examples of calculation and display of other OZT. As shown in Fig. 16A, when the other ship is traveling at a high speed, the front end of the own ship's warning area P may come into contact with the rear end of the other ship's ship area BS at both the front end LF and the rear end LR of the risk range L.

[0107] In this case, the risk range identification unit 11 outputs the rear end LR and front end LF of the risk range L, the representative point SF of the ship located at a position corresponding to the rear end LR, and the representative point SR of the ship located at a position corresponding to the front end LF to the display control unit 12 as the positions of the vertices of the OZT.

[0108] As shown in Figure 16B, the display control unit 12 displays on the screen of the display unit 2 a rectangular OZT whose vertices are the aft end LR and forward end LF of the risk range L, the ship's representative point SF located at a position corresponding to the aft end LR, and the ship's representative point SR located at a position corresponding to the forward end LF.

[0109] By displaying such a rectangular OZT, the user can understand that regardless of whether the user proceeds ahead or behind the OZT, the user's ship will be in a match-passing relationship with the other ship, crossing behind it.

[0110] 16C, the display control unit 12 may display an indicator MK in association with the front end LF of the risk range L. Displaying such an indicator MK makes it easier for the user to grasp the traveling direction of the other ship.

[0111] [Second Modification] The following describes the second modified example. Configurations that overlap with those in the above embodiment are given the same reference numerals, and detailed descriptions thereof may be omitted.

[0112] 17 is a diagram showing an example of the display of OZT according to the second modified example. The figure shows an example in which OZT1, which indicates the risk of collision between the own ship and another ship 1, and OZT2, which indicates the risk of collision between the own ship and another ship 2, partially overlap.

[0113] The display control unit 12 differentiates the display aspects, such as shading, color, or texture, of the overlapping portion OL of OZT1, 2 from the other portions. For example, the display control unit 12 displays the overlapping portion OL darker than the other portions. By creating each of OZT1, 2 semi-transparently and displaying them overlapping, the overlapping portion OL is displayed darker than the other portions.

[0114] This allows the overlapping area OL of the multiple OZTs 1 and 2, where the ship may collide with multiple other ships 1 and 2, to be displayed separately from other areas, making it easier for the user to understand the zones with a higher risk of collision.

[0115] 18A to 18C are diagrams showing examples of calculation and display of other OZT. The risk area identification unit 11 identifies, as risk areas, a collision area L1 (see FIG. 18A) where the ship area S of the own ship overlaps with the ship area BS of the other ship, and an approach area L2 (see FIG. 18B) where the warning area P of the own ship overlaps with the warning area BP of the other ship.

[0116] 18A, the aft end L1R of the collision area L1 is the position where the forward end of the ship area S of the own ship abuts against the aft end of the ship area BS of the other ship. The forward end L1F of the collision area L1 is the position where the aft end of the ship area S of the own ship abuts against the forward end of the ship area BS of the other ship.

[0117] Furthermore, the representative point S1F of the ship located at a position corresponding to the rear end L1R of the collision range L1 and the representative point S1R of the ship located at a position corresponding to the front end L1F of the collision range L1 are the reference position RP of the ship (see Figure 5).

[0118] As shown in Figure 18B, the rear end L2R of approach range L2 is the position where the front end of the ship's surveillance area P abuts the rear end of the other ship's surveillance area BP. The front end L2F of approach range L2 is the position where the rear end of the ship's surveillance area P abuts the front end of the other ship's surveillance area BP.

[0119] Furthermore, the representative point S2F of the ship, which is located at a position corresponding to the rear end L2R of the approach range L2, and the representative point S1R of the ship, which is located at a position corresponding to the front end L1F of the collision range L1, are the reference position RP of the ship (see Figure 5).

[0120] The display control unit 12 displays on the screen of the display unit 2 a rectangle OZT1 having vertices at points L1R, L1F, S1F, and S1R relating to the collision range L1, and a rectangle OZT2 having vertices at points L2R, L2F, S2F, and S2R relating to the approach range L2.

[0121] OZT1, which is related to the collision range L1, is a zone where there is a high possibility of a collision between the ship and another ship in the future. OZT2, which is related to the approach range L2, is a zone where there is a high possibility of a collision between the ship and another ship in the future, although the possibility of a collision is not as high as in OZT1. OZT1 is included in OZT2.

[0122] The display control unit 12 differentiates the display modes, such as shading, color, or texture, between OZT1 related to the collision range L1 and OZT2 related to the approach range L2. For example, the display control unit 12 displays OZT1 darker than OZT2. By creating each of OZT1 and OZT2 semi-transparently and displaying them overlapping each other, OZT1 is displayed darker than OZT2.

[0123] According to this, OZT1 relating to the collision range L1 and OZT2 relating to the approach range L2 are displayed in a distinguishable manner, making it easier for the user to grasp the degree of risk of collision or approach.

[0124] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made by those skilled in the art. [Explanation of symbols]

[0125] 1 Information processing device, 2 Display unit, 3 Radar, 4 AIS, 5 GNSS receiver, 6 Gyrocompass, 7 ECDIS, 8 Alarm unit, 11 Risk area identification unit, 12 Display control unit, 13 Size data storage unit, 100 Ship monitoring system

Claims

1. a first data generation unit that generates first vessel data representing the position and velocity of the first vessel; a second data generation unit that generates second vessel data representing the position and velocity of the second vessel; a risk range identification unit that identifies a risk range within the predicted course of the second vessel where a risk value representing a risk of collision between the first vessel and the second vessel is equal to or greater than a threshold, based on the positions of the first vessel and the second vessel at each time point predicted from the first vessel data and the second vessel data, when it is assumed that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel; a display unit that displays a polygonal OZT (Obstacle Zone by Target) having at least the aft and front ends of the risk zone and a representative point of the first vessel located at a position corresponding to the aft end of the risk zone as vertices; A vessel monitoring system comprising:

2. The OZT is a rectangle with vertices at the aft and forward ends of the risk range, a representative point of the first vessel located at a position corresponding to the aft end of the risk range, and a representative point of the first vessel located at a position corresponding to the forward end of the risk range. The vessel monitoring system of claim 1 .

3. the rear end of the risk range is a position where the front end of the surveillance area set around the first vessel abuts a point representing the position of the second vessel, the rear end of the vessel area occupied by the second vessel, or the rear end of the surveillance area set around the second vessel; 3. A vessel monitoring system according to claim 1 or 2.

4. the forward end of the risk range is a position where the rear end of the alert area set around the first vessel abuts a point representing the position of the second vessel, the forward end of the vessel area occupied by the second vessel, or the forward end of the alert area set around the second vessel; 4. A vessel monitoring system according to claim 1.

5. the rear end of the risk range is a position where the rear end of the alert area set around the first vessel abuts a point representing the position of the second vessel, a front end of the vessel area occupied by the second vessel, or a front end of the alert area set around the second vessel; 3. A vessel monitoring system according to claim 1 or 2.

6. the forward end of the risk range is a position where the forward end of the alert area set around the first vessel abuts a point representing the position of the second vessel, the aft end of the vessel area occupied by the second vessel, or the aft end of the alert area set around the second vessel; 6. A vessel monitoring system according to claim 1, 2, 3 or 5.

7. a representative point of the first vessel located at a position corresponding to the rear end of the risk range is the front end of the vessel area occupied by the first vessel, a point representing the position of the first vessel, the rear end of the vessel area occupied by the first vessel, or the rear end of a warning area set around the first vessel; 5. A vessel monitoring system according to claim 1.

8. a representative point of the first vessel located at a position corresponding to the forward end of the risk range is the aft end of the vessel area occupied by the first vessel, a point representing the position of the first vessel, the forward end of the vessel area occupied by the first vessel, or the forward end of a warning area set around the first vessel; 5. A vessel monitoring system according to claim 1.

9. The OZT is a triangle with vertices at the aft and forward ends of the risk range and a representative point of the first vessel located at a position corresponding to the aft end of the risk range. The vessel monitoring system of claim 1 .

10. When the first vessel is in a facing relationship with the second vessel crossing ahead of the risk range, the display unit displays the OZT as a triangle with vertices at the aft and front ends of the risk range and a representative point of the first vessel located at a position corresponding to the aft end of the risk range.

10. A vessel monitoring system according to claim 9.

11. When the second vessel is in a facing relationship crossing ahead of the first vessel forward of the forward end of the risk range, the display unit displays the OZT as a rectangle with vertices at the rear and front ends of the risk range, a representative point of the first vessel located at a position corresponding to the rear end of the risk range, and a representative point of the first vessel located at a position corresponding to the forward end of the risk range.

11. A vessel monitoring system according to claim 10.

12. The display unit displays an indicator associated with the front end of the risk range of the OZT.

12. A vessel monitoring system according to any one of claims 9 to 11.

13. the display unit differentiates a display mode of a portion where the plurality of OZTs overlap among the plurality of OZTs displayed for the plurality of second vessels from a display mode of a portion where the plurality of OZTs do not overlap.

13. A vessel monitoring system according to any one of claims 1 to 12.

14. the risk area identification unit identifies, as the risk area, a collision area in which the ship area occupied by the first ship overlaps with the ship area occupied by the second ship, and an approach area in which a warning area set around the first ship overlaps with the ship area occupied by the second ship or with a warning area set around the second ship; the display unit causes the collision range and the approach range to be displayed in different manners. A vessel monitoring system according to any one of claims 1 to 13.

15. the first data generation unit is mounted on the first vessel and includes a GNSS (Global Navigation Satellite System) receiver that detects the position of the first vessel based on radio waves received from a GNSS; A vessel monitoring system according to any one of claims 1 to 14.

16. the second data generation unit includes a radar mounted on the first vessel and configured to detect the position and speed of the second vessel from echo data generated by receiving reflected waves of radio waves emitted around the first vessel; 16. A vessel monitoring system according to any one of claims 1 to 15.

17. a first data generation unit generating first vessel data representing the position and velocity of the first vessel; a second data generation unit generating second vessel data representing the position and velocity of the second vessel; Identifying a risk range within the predicted course of the second vessel in which a risk value representing the risk of collision between the first vessel and the second vessel is equal to or greater than a threshold, based on the positions of the first vessel and the second vessel at each time point predicted from the first vessel data and the second vessel data, when it is assumed that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel; Displaying on a display unit a polygonal OZT (Obstacle Zone by Target) having at least the aft and front ends of the risk zone and a representative point of the first vessel located at a position corresponding to the aft end of the risk zone as vertices; Ship monitoring method.

18. a risk range identification unit that identifies a risk range within the predicted course of the second vessel in which a risk value representing a risk of collision between the first vessel and the second vessel is equal to or greater than a threshold, based on the positions of the first vessel and the second vessel at each time point predicted from first vessel data representing the position and speed of the first vessel and second vessel data representing the position and speed of the second vessel, when it is assumed that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel; a display control unit that displays, on a display unit, a polygonal OZT (Obstacle Zone by Target) having at least vertices that are the aft and front ends of the risk zone and a representative point of the first vessel located at a position corresponding to the aft end of the risk zone; An information processing device comprising:

19. Identifying a risk range within the predicted course of the second vessel in which a risk value representing the risk of collision between the first vessel and the second vessel is equal to or greater than a threshold, based on the positions of the first vessel and the second vessel at each time point predicted from first vessel data representing the position and speed of the first vessel and second vessel data representing the position and speed of the second vessel, when it is assumed that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel; and Displaying on a display unit a polygonal OZT (Obstacle Zone by Target) having at least the aft and front ends of the risk zone and a representative point of the first vessel located at a position corresponding to the aft end of the risk zone as vertices; A program that causes a computer to execute the following.

Images