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

Abstract

[Problem] To provide a ship monitoring system which can attain an improvement in the accuracy of predicting a risk of collisions or proximity. [Solution] The present invention provides a ship monitoring system comprising: a first data generation unit that generates first ship data expressing the position and velocity of a first ship; a second data generation unit that generates second ship data expressing the position and velocity of a second ship; a risk area specification unit that specifies a risk area where there is an overlap between a vessel zone occupied by the first ship or a warning zone set around the first ship and a vessel zone occupied by the second ship or a warning zone set around the second ship within a predicted course of the second ship on the basis of the position of the first ship and the position of the second ship at respective time points predicted from the first ship data and the second ship data under the assumption that the first ship will change course to any direction and will cut across the predicted course of the second ship; and a display unit that displays an OZT in 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 evaluating the risk of collision between ships. For example, Non-Patent Document 1 discloses a method for displaying OZT (Obstacle Zone by Target). [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] However, conventional methods for displaying OZT treat ships as points and calculate risk without taking into account the size of the ship. As a result, situations such as ships coming too close to each other can occur near the boundaries of the range in which the OZT is displayed.

[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 improve the accuracy of predicting the risk of collision or approach. [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 in the predicted course of the second ship where a warning area set around the ship area occupied by the first ship or around the first ship overlaps with a warning area set around the ship area occupied by the second ship or around the second ship, 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 an OZT in 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 predicted from the first ship data and the second ship data at each point in time when it is assumed that the first ship will change course in an arbitrary direction and cross the predicted course of the second ship, a risk range is identified within the predicted course of the second ship where a warning area set around the ship area occupied by the first ship or around the first ship overlaps with a warning area set around the ship area occupied by the second ship or around the second ship, and an OZT is displayed in the risk range on a display unit.

[0008] In addition, another aspect of an information processing device of the present invention includes a risk area identification unit that identifies a risk area in the predicted course of the second ship where a warning area set around the ship area occupied by the first ship or a warning area set around the first ship overlaps with a warning area set around the ship area occupied by the second ship or a warning area set around the second ship, based on the position of the first ship and the position of the second ship at each point in time predicted from first ship data representing the position and speed of the first ship and second ship data representing the position and speed of the second ship, when assuming that the first ship will change course in an arbitrary direction and cross the predicted course of the second ship, and a display control unit that displays an OZT in the risk area on a display unit.

[0009] In addition, another aspect of the program of the present invention causes a computer to identify a risk area in the predicted course of the second vessel where a warning area set around the ship area occupied by the first vessel or a warning area set around the first vessel overlaps with a warning area set around the ship area occupied by the second vessel, 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, assuming that the first vessel will change course in an arbitrary direction and cross the predicted course of the second vessel, and display an OZT (Obstacle Zone by Target) in the risk area on a display unit. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the accuracy of predicting the risk of collision or approach. [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. 1 is a diagram illustrating an example of the configuration of an information processing device according to an embodiment. [Figure 4]FIG. 10 is a diagram for explaining size data. [Figure 5] FIG. 10 is a diagram for explaining size data. [Figure 6] FIG. 10 is a diagram illustrating an example of a procedure of a process executed by a risk range identification unit. [Figure 7A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 7B] FIG. 10 is a diagram showing a display example of an OZT. [Figure 8] FIG. 10 is a diagram showing an example of calculation of 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 12A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 12B] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 12C] FIG. 10 is a diagram showing a display example of an OZT. [Figure 13A] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 13B] FIG. 10 is a diagram showing an example of calculation of OZT. [Figure 13C] FIG. 10 is a diagram showing a display example of an OZT. [Figure 14] FIG. 10 is a diagram for explaining size data. [Figure 15] FIG. 10 is a diagram showing an example of calculation of 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] 3 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.

[0033] 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.

[0034] The risk area identification unit 11 identifies a risk area L where the alert area P set around the ship area occupied by the own ship or around the own ship overlaps with the alert area P set around the ship area occupied by the other ship or around the other ship, based on the position of the own ship and the position of the other ship at each point in time predicted from the own ship data and the other ship data when it is assumed that the own ship will change course in an arbitrary direction and cross the predicted course of the other ship (see Figure 7A).

[0035] The display control unit 12 causes the display unit 2 to display an OZT (Obstacle Zone by Target) including the risk range L identified by the risk range identifying unit 11 (see FIG. 7B).

[0036] 4 and 5 are diagrams for explaining the size data of the ship itself stored by 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.

[0037] 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).

[0038] A collision is considered to occur when another ship is present within the ship area S of the own ship. As shown in Figure 5, within the ship area S of the own ship, the risk value is set to the maximum of 1.

[0039] 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.

[0040] Note that the warning area P does not have to be set behind the ship. In other words, the length PL2 may be 0. Also, the warning area P does not have to be set ahead of the ship. In other words, the length PL1 may be 0.

[0041] 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.

[0042] In this embodiment, as shown in Figure 5(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 5(b), the risk value in the alert area P may be set to gradually decrease the further away from the ship.

[0043] In this embodiment, the ship's own ship area S and warning area P are represented by lines in the fore-and-aft direction, but this is not limited to this, and the ship's own ship area S and warning area P may also be represented by a rectangular area by adding the widthwise length.

[0044] 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.

[0045] Fig. 6 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 diagram in accordance with a program, thereby functioning as the risk range identification unit 11. Figs. 7A and 7B are diagrams showing an example of calculation and display of OZT.

[0046] 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).

[0047] 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.

[0048] The predicted position of the ship at each time point is represented by multiple concentric circles calculated for each of multiple discrete time points. Alternatively, the predicted position of the ship at each time point may be represented by a circular equation that includes the elapsed time from a reference time point (details will be described later).

[0049] 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.

[0050] 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).

[0051] 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.

[0052] 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).

[0053] 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).

[0054] 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).

[0055] 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.

[0056] 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).

[0057] In the example of Figure 7A, the risk area identification unit 11 sets the ship area S and warning area P of the own ship using the size data of the own ship (see Figures 4 and 5), sets the ship area BS of the other ship, and determines whether the ship area BS of the other ship is included within the ship area S or warning area P of the own ship.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] As shown in Figure 7A, when setting the ship area BS or warning area BP of another ship, the separation distance between the point representing the predicted position of the own ship and the front or rear end of the ship area BS of the other ship may be calculated. As shown in Figure 8, when setting the ship area BS and warning area BP of another ship, the separation distance between the point representing the predicted position of the own ship and the front or rear end of the warning area BP of the other ship may be calculated.

[0062] The risk range identification unit 11 sets the risk value to the maximum of 1 if the ship area BS 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 5(a)).The threshold is set between 0 and 1, and if the ship area BS of another ship is included within the ship area S or warning area P of the own ship, the risk value will be above the threshold.

[0063] Alternatively, the risk value in the alert area P may be set to gradually decrease the further away from the own ship (see Figure 5(b)). In this case, when the other ship's ship area BS 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.

[0064] 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 come into contact is calculated.

[0065] As shown in Figure 8, 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.

[0066] 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 tyis V t is the y component of

[0067]

number

[0068] 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.

[0069]

number

[0070] 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.

[0071] Here, we have explained how to calculate the position where the forward end of the ship's own ship area and the aft end of the other ship's ship area abut, but calculations can also be made in a similar manner 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 surveillance area BP, as shown in Figure 11.

[0072] Returning to the explanation of Figure 6, 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). The fore-and-aft direction of the risk range L corresponds to the fore-and-aft direction of the other ship.

[0073] As described above, in this embodiment, the risk value is greater than or equal to the threshold when the ship area BS of another ship is included within the ship area S or alert area P of the own ship, so as shown in Figure 7A, the aft end LR of the risk area L is the position where the forward end of the alert area P of the own ship 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 alert area P of the own ship abuts the forward end of the ship area BS of the other ship.

[0074] The risk area identification unit 11 outputs the identified risk area L as the range of OZT to the display control unit 12, and ends the processing. If there are multiple other ships, the processing of S13 to S18 is executed for each of the multiple other ships.

[0075] In the example of Figure 7B, the display control unit 12 displays an OZT in the risk area L identified by the risk area identification unit 11. The OZT has a shape extending in the same direction as the predicted course of the other ship, for example, a rounded rectangle with semicircular ends. However, the OZT is not limited to this, and may be an ellipse or the like.

[0076] The edge of the OZT between the forward end LF and the aft end LR of the risk range L is a straight line extending along the predicted course of the other ship. The distance between this line and the predicted course of the other ship, as well as the radius of the semicircles at both ends, use a predetermined safe separation distance.

[0077] The facing relationship between the own ship and the other ship is not limited to the example in Figure 7A, and for example, as shown in Figure 9, at both the forward end LF and the aft end LR of the risk area L, the forward end of the own ship's surveillance area P may abut the aft end of the other ship's ship area BS. Also, as shown in Figure 10, when two risk areas L occur, in the risk area L farthest from the other ship, the aft end LR of the risk area L may be a position where the aft end of the own ship's surveillance area P abuts the forward end of the other ship's ship area BS, and the forward end LF of the risk area L may be a position where the forward end of the own ship's surveillance area P abuts the aft end of the other ship's ship area BS.

[0078] Not limited to the above example, the risk area identification unit 11 may also determine whether the ship's ship area S or surveillance area P overlaps with the 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.

[0079] Furthermore, the risk area identification unit 11 may determine whether the ship area S of the own ship overlaps with the ship area BS or the warning area BP of another ship, without setting a warning area P of the own ship.

[0080] According to the embodiment described above, a risk range L is identified where the ship's own ship's ship area S or warning area P overlaps with the other ship's ship area BS or warning area BP, thereby making it possible to improve the accuracy of predicting the risk of collision or approach between the ship and the other ship.

[0081] [First Modification] The following describes the first modified example. Configurations that overlap with those in the above embodiment are given the same reference numerals, and detailed descriptions thereof may be omitted.

[0082] 12A to 12C are diagrams showing examples of calculation and display of OZT according to Modification 1. The risk area identification unit 11 identifies, as risk areas, a collision area L1 (see FIG. 12A) 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. 12B) where the warning area P of the own ship overlaps with the warning area BP of the other ship.

[0083] 12A, 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.

[0084] As shown in Figure 12B, 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.

[0085] The display control unit 12 displays on the screen of the display unit 2 OZT1 relating to the collision range L1 and OZT2 relating to the approach range L2.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] [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.

[0090] 13A to 13C are diagrams showing examples of calculation and display of OZT according to the second modified example. The risk area identification unit 11 identifies as risk areas a first risk area L3 (see FIG. 13A) where the ship area S of the own ship overlaps with the ship area BS or the alert area BP of the other ship, and a second risk area L4 (see FIG. 13C) where the ship area S or the alert area P of the own ship overlaps with the ship area BS of the other ship.

[0091] As shown in Figure 13A, the aft end L3R of the first risk area L3 is the position where the forward end of the ship's ship area S abuts the aft end of the other ship's warning area BP. The forward end L3F of the first risk area L3 is the position where the aft end of the ship's ship area S abuts the forward end of the other ship's warning area BP.

[0092] As shown in Figure 13B, the aft end L4R of the second risk area L4 is the position where the forward end of the ship's warning area P abuts the aft end of the other ship's ship area BS. The forward end L4F of the second risk area L4 is the position where the aft end of the ship's warning area P abuts the forward end of the other ship's ship area BS.

[0093] The display control unit 12 displays OZT3 relating to the first risk range L3 and OZT4 relating to the second risk range L4 on the screen of the display unit 2. OZT3 relating to the first risk range L3 and OZT4 relating to the second risk range L4 partially overlap.

[0094] The display control unit 12 differentiates the display aspects, such as shading, color, or texture, of the overlapping portion OL of OZT3, 4 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 OZT3, 4 semi-transparently and displaying them overlapping, the overlapping portion OL is displayed darker than the other portions.

[0095] This results in a display similar to that of the first modified example, making it easier for the user to grasp the degree of risk of collision or approach.

[0096] [Third Modification] The third modified example will be described below. Configurations that overlap with those in the above embodiment will be given the same reference numerals and detailed descriptions thereof may be omitted.

[0097] 14 is a diagram for explaining size data according to Modification 3. The size data includes not only the longitudinal lengths L1, L2 of the ship's ship area S and the longitudinal lengths PL1, PL2 of the surveillance area P, but also the widthwise lengths L3, L4 of the ship's ship area S and the widthwise lengths PL3, PL4 of the surveillance area P.

[0098] Therefore, the ship area S of the ship is represented as a rectangular area. The length L3 is the length from the reference position RP of the ship to the left end of the ship, and the length L4 is the length from the reference position RP of the ship to the right end of the ship.

[0099] The ship's surveillance area P is also represented as a rectangular area. Length PL3 is the length from the ship's left edge to the left edge of the surveillance area P, and length PL4 is the length from the ship's right edge to the right edge of the surveillance area P.

[0100] For other ships, similar to the own ship, widthwise lengths may be set for the ship area BS and the warning area BP of the other ship. The widthwise length of the other ship may be a predetermined length according to the type of ship included in the AIS, for example, or may be estimated from the echo data of the radar 3.

[0101] As shown in Figure 15, in this modified example, the risk area identification unit 11 determines whether the rectangular ship area S or warning area P of the own ship overlaps with the rectangular ship area BS of another ship, and identifies the risk area L.

[0102] When the other ship is about to cross in front of the own ship, there is a point where the left front edge of the own ship's warning area P meets the right rear edge of the other ship's ship area. The intersection of the own ship's course direction and the other ship's predicted course at this time is the rear end LR of the risk area L.

[0103] Furthermore, near the point where the ship is in a meeting relationship with the other ship, there is a point where the left rear end of the ship's warning area P meets the left front end of the other ship's ship area. The intersection of the ship's course direction and the other ship's predicted course at this time is the front end LF of the risk area L.

[0104] Without being limited to this, the risk area identification unit 11 may set the own ship's ship area S and the other ship's ship area BS, and determine whether the rectangular own ship's ship area S overlaps with the rectangular other ship's ship area BS. The risk area identification unit 11 may also set the own ship's ship area S and the other ship's ship area BS and warning area BP, and determine whether the rectangular own ship's ship area S overlaps with the rectangular other ship's ship area BS or warning area BP.

[0105] In addition, the risk area identification unit 11 may set the ship area S and alert area P of the own ship and the ship area BS and alert area BP of another ship, and determine whether the rectangular ship area S or alert area P of the own ship overlaps with the rectangular ship area BS or alert area BP of the other ship.

[0106] This allows the risk range L to be determined taking into consideration the width of the ship area or alert area, making it possible to improve the accuracy of predicting the risk of collision or approach between one's own ship and another ship.

[0107] 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]

[0108] 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 ship data representing the position and velocity of a first ship; a second data generation unit that generates second vessel data representing the position and velocity of the second vessel; a risk area identification unit that identifies a risk area within the predicted course of the second vessel where a warning area set around the first vessel or a ship area occupied by the first vessel overlaps with a warning area set around the second vessel, 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 an OZT (Obstacle Zone by Target) in the risk range; Equipped with the rear end of the risk range is a position where the front end of the ship area occupied by the first ship or the front end of the alert area set around the first ship abuts the rear end of the ship area occupied by the second ship or the rear end of the alert area set around the second ship; Ship monitoring system.

2. A first data generation unit that generates first ship data representing the position and velocity of a first ship; a second data generation unit that generates second vessel data representing the position and velocity of the second vessel; a risk area identification unit that identifies a risk area within the predicted course of the second vessel where a warning area set around the first vessel or a ship area occupied by the first vessel overlaps with a warning area set around the second vessel, 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 an OZT (Obstacle Zone by Target) in the risk range; Equipped with the forward end of the risk range is a position where the aft end of the ship area occupied by the first ship or the aft end of the alert area set around the first ship abuts the forward end of the ship area occupied by the second ship or the forward end of the alert area set around the second ship; Ship monitoring system.

3. A first data generation unit that generates first ship data representing the position and velocity of a first ship; a second data generation unit that generates second vessel data representing the position and velocity of the second vessel; a risk area identification unit that identifies a risk area within the predicted course of the second vessel where a warning area set around the first vessel or a ship area occupied by the first vessel overlaps with a warning area set around the second vessel, 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 an OZT (Obstacle Zone by Target) in the risk range; Equipped with the rear end of the risk range is a position where the rear end of the ship area occupied by the first ship or the rear end of the alert area set around the first ship abuts the front end of the ship area occupied by the second ship or the front end of the alert area set around the second ship; Ship monitoring system.

4. A first data generation unit that generates first ship data representing the position and velocity of a first ship; a second data generation unit that generates second vessel data representing the position and velocity of the second vessel; a risk area identification unit that identifies a risk area within the predicted course of the second vessel where a warning area set around the first vessel or a ship area occupied by the first vessel overlaps with a warning area set around the second vessel, 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 an OZT (Obstacle Zone by Target) in the risk range; Equipped with the forward end of the risk range is a position where the forward end of the ship area occupied by the first ship or the forward end of the alert area set around the first ship abuts the aft end of the ship area occupied by the second ship or the aft end of the alert area set around the second ship; Ship monitoring system.

5. The risk area identification unit identifies the risk area based on a calculation formula for calculating the time when the front or rear end of the ship area occupied by the first ship or the front or rear end of the alert area set around the first ship coincides with the front or rear end of the ship area occupied by the second ship or the front or rear end of the alert area set around the second ship in each direction when it is assumed that the first ship will change course in any direction from its current position and continue sailing.

5. A vessel monitoring system according to claim 1.

6. 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 a display mode of the OZT displayed in the collision range and a display mode of the OZT displayed in the approach range to differ from each other.

6. A vessel monitoring system according to any one of claims 1 to 5.

7. the risk area identification unit identifies as the risk areas a first risk area in which the ship area occupied by the first ship overlaps with the ship area occupied by the second ship or a warning area set around the second ship, and a second risk area in which the ship area occupied by the first ship or a warning area set around the first ship overlaps with the ship area occupied by the second ship; The display unit causes a display mode of an overlapping portion of the OZT displayed in the first risk range and a display mode of a non-overlapping portion of the OZT displayed in the second risk range to differ from each other.

6. A vessel monitoring system according to any one of claims 1 to 5.

8. At least one of the ship area occupied by the first ship, the alert area set around the first ship, the ship area occupied by the second ship, and the alert area set around the second ship has a predetermined width.

8. A vessel monitoring system according to any one of claims 1 to 7.

9. 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; 9. A vessel monitoring system according to any one of claims 1 to 8.

10. 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; 10. A vessel monitoring system according to any one of claims 1 to 9.

11. 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 in the predicted course of the second vessel where a warning area set around the first vessel or the ship area occupied by the first vessel overlaps with a warning area set around the second vessel, based on the positions of the first vessel and the second vessel at each time 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; On the display unit, an OZT (Obstacle Zone by Target) is displayed in the risk range. A vessel monitoring method, comprising: the rear end of the risk range is a position where the front end of the ship area occupied by the first ship or the front end of the alert area set around the first ship abuts the rear end of the ship area occupied by the second ship or the rear end of the alert area set around the second ship; Ship monitoring method.

12. a risk area identification unit that identifies a risk area within the predicted course of the second vessel where a ship area occupied by the first vessel or a warning area set around the first vessel overlaps with a ship area occupied by the second vessel or a warning area set around the second vessel, 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 an OZT (Obstacle Zone by Target) in the risk area on the display unit; Equipped with the rear end of the risk range is a position where the front end of the ship area occupied by the first ship or the front end of the alert area set around the first ship abuts the rear end of the ship area occupied by the second ship or the rear end of the alert area set around the second ship; Information processing device.

13. Identifying a risk range in the predicted course of the second vessel where a warning area set around the first vessel or a ship area occupied by the first vessel overlaps with a warning area set around the second vessel, 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 an OZT (Obstacle Zone by Target) in the risk range on a display unit; on the computer, the rear end of the risk range is a position where the front end of the ship area occupied by the first ship or the front end of the alert area set around the first ship abuts the rear end of the ship area occupied by the second ship or the rear end of the alert area set around the second ship; program.

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