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

Abstract

[Problem] To provide a ship monitoring system in which an improvement in the accuracy of predicting a collision risk can be attained. [Solution] This ship monitoring system comprises: a turning information input unit into which is input the bearing and turn rate of a first ship at the current point in time; a position / ship speed information input unit into which is input the position and ship speed of the first ship at the current point in time; a second ship predicted route information input unit into which is input the position and ship speed of a second ship at the current point in time as well as the predicted route thereof after the current point in time; an assessment point setting unit which sets an assessment point along the predicted route on the basis of the position, ship speed, and predicted route of the second ship and which outputs the position of the assessment point and a second ship sailing time, which is the time required for the second ship to sail to the assessment point from the current point in time; a route setting unit which maintains the ship speed of the first ship at the current point in time starting from the bearing of the first ship and the position of the first ship, sets a route to sail toward the assessment point by turning at the turn rate to modify the course of the first ship toward the assessment point, and outputs the route and a first ship sailing time for reaching the assessment point; and a risk value calculation unit which calculates a collision risk value at the assessment point on the basis of the predicted route and second ship sailing time of the second ship, as well as the route and first ship sailing time of the first ship.

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] [Non-patent literature]

[0003] [Non-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 the conventional method of displaying OZT, the predicted position of the ship is calculated under the assumption that the ship will instantly change course from its current position and continue straight ahead. However, in reality, the ship gradually changes course while turning, which can lead to errors in the predicted position of the ship, and a discrepancy between the area where the OZT is displayed and the area where there is an actual risk of collision.

[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 collision risk prediction. [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 turning information input unit to which the current heading and turning rate of a first ship are input, a position and speed information input unit to which the current position and speed of the first ship are input, a second ship predicted route information input unit to which the current position, speed and predicted route of a second ship are input, and a second ship prediction route information input unit to which the current position, speed and predicted route of the ... The system comprises a decision point setting unit that outputs a vessel navigation time, a route setting unit that sets a route for the first vessel to navigate toward the decision point by maintaining the current vessel speed, turning at the turning rate, and changing course toward the decision point, starting from the heading and position of the first vessel, and outputs the route and the first vessel navigation time to reach the decision point, and a risk value calculation unit that calculates a collision risk value at the decision point based on the predicted route and second vessel navigation time of the second vessel, and the route and first vessel navigation time of the first vessel.

[0007] Another aspect of the ship monitoring method of the present invention includes inputting the current direction and rate of turn of one ship, inputting the current position and speed of the first ship, inputting the current position, speed and predicted route of the second ship from the current time, setting a judgment point on the predicted route based on the position, speed and predicted route of the second ship, outputting the position of the judgment point and a second vessel travel time required for the second ship to travel from the current time to the judgment unit, setting a route for the first ship to travel to the judgment point by maintaining the current vessel speed, turning at the rate of turn and changing course toward the judgment point, starting from the direction and position of the first ship, and outputting the route and the first vessel travel time to reach the judgment point, and calculating a collision risk value at the judgment point based on the predicted route and second vessel travel time of the second ship, and the route and first vessel travel time of the first ship.

[0008] Another aspect of the information processing device of the present invention includes a turning information input unit to which the current direction and turning rate of a first vessel are input, a position and vessel speed information input unit to which the current position and vessel speed of the first vessel are input, a second vessel predicted course information input unit to which the current position, vessel speed and predicted course of a second vessel from the current time are input, and a second vessel predicted course information input unit to which a judgment point is set on the predicted course based on the position, vessel speed and predicted course of the second vessel, and a second vessel navigation time required for the second vessel to navigate from the current time to the judgment unit. a route setting unit that sets a route for the first vessel to navigate toward the judgment point by maintaining the current vessel speed, turning at the turning rate, and changing course toward the judgment point, starting from the heading and position of the first vessel, and outputs the route and the first vessel navigation time to arrive at the judgment point; and a risk value calculation unit that calculates a collision risk value at the judgment point based on the predicted route and second vessel navigation time of the second vessel, and the route and first vessel navigation time of the first vessel.

[0009] In addition, another aspect of the program of the present invention includes a turning information input unit to which the current direction and turning rate of a first vessel are input, a position and speed information input unit to which the current position and speed of the first vessel are input, a second vessel predicted course information input unit to which the current position, speed and predicted course of a second vessel are input, and a judgment unit to set a judgment point on the predicted course based on the position, speed and predicted course of the second vessel and output the position of the judgment point and a second vessel navigation time required for the second vessel to navigate from the current time to the judgment unit. The computer functions as a point setting unit, a route setting unit that sets a route for the first vessel to navigate toward the judgment point by maintaining the current vessel speed based on the heading and position of the first vessel, turning at the turning rate and changing course toward the judgment point, and outputs the route and the first vessel navigation time to arrive at the judgment point, and a risk value calculation unit that calculates a collision risk value at the judgment point based on the predicted route and second vessel navigation time of the second vessel, and the route and first vessel navigation time of the first vessel. [Effects of the Invention]

[0010] According to the present invention, it is possible to improve the accuracy of predicting the risk of collision. [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 3A] FIG. 1 is a diagram showing a calculation example of a conventional OZT. [Figure 3B] FIG. 1 is a diagram showing a calculation 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 illustrating an example of the contents of an ROT threshold table. [Figure 6] 1 is a diagram showing an example of a procedure of a vessel monitoring method according to an embodiment; [Figure 7] FIG. 10 is a diagram for explaining a calculation example of OZT. [Figure 8] FIG. 10 is a diagram for explaining a calculation example of OZT. [Figure 9] FIG. 10 is a diagram showing an example of the procedure of a ship monitoring method according to a modified example. [Figure 10] FIG. 10 is a diagram for explaining a calculation example 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] 3A and 3B are diagrams showing an example of a conventional OZT calculation. 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 conventional OZT calculations, collision risk is calculated under the assumption that the ship will instantly change course and proceed straight toward a decision point on the other ship's predicted course, as shown in Figure 3A. However, as shown in Figure 3B, in reality, the ship will turn toward the decision point, which can result in a discrepancy between the area where OZT is displayed and the area where there is an actual risk of collision.

[0034] For example, at the decision point where OZT is displayed, which is the farthest from the ship's bow line, it is determined that there is a risk of collision under the assumption that the ship will instantly change course and proceed straight ahead, but by the time the ship actually turns and reaches the decision point, the other ship will have passed the decision point and no collision will occur. In this way, OZT may be displayed at a decision point where a collision will not actually occur.

[0035] Therefore, in this embodiment, as will be described below, risk calculations are performed taking into account the turning of the ship itself, thereby improving the accuracy of collision risk predictions.

[0036] 4 is a diagram showing an example of the configuration of an information processing device 1 according to an embodiment, which realizes a ship monitoring method according to the embodiment. The information processing device 1 includes a turning information input unit 11, a position and ship speed information input unit 12, a predicted other ship route information input unit 13, a decision point setting unit 14, a route setting unit 15, a risk value calculation unit 16, and a display control unit 17. These functional units are realized by the CPU of the information processing device 1 executing information processing in accordance with a program.

[0037] Based on the own ship data and the other ship data, the information processing device 1 calculates a risk value representing the risk of collision between the own ship and the other ship at each judgment point on the other ship's predicted course, assuming that the own ship turns from its current position and current direction and heads toward each judgment point on the other ship's predicted course (see Figure 7).

[0038] Based on the ship's data, the current heading and turning rate of the ship are input to the turning information input unit 11. Hereinafter, the turning rate will also be referred to as "ROT" (Rate of Turn).

[0039] Specifically, an ROT threshold is input to the turning information input unit 11. The ROT threshold is the upper limit of the ROT allowed for the ship, and is an example of a predetermined ROT. The ROT threshold is set, for example, by input from the user. The turning information input unit 11 uses an ROT equal to or less than the ROT threshold.

[0040] Alternatively, an ROT threshold table may be prepared in which the overall length of the ship and the ROT threshold are associated with each other, as shown in Fig. 5, and the turning information input unit 11 may acquire the ROT threshold corresponding to the overall length of the ship. Instead of the overall length of the ship, other parameters representing the size of the ship, such as the volume, weight, or type of ship, may be used.

[0041] The position and speed information input unit 12 receives the current position and speed of the ship based on the ship data.

[0042] Based on other ship data, the current position, speed, and predicted course of the other ship from the current point onward are input to the other ship predicted course information input unit 13. The predicted course of the other ship is calculated under the assumption that the other ship will navigate maintaining the speed and heading from its current position.

[0043] The decision point setting unit 14 sets decision points on the predicted route based on the position, speed, and predicted route of other ships, and outputs the position of the decision point and the other ship travel time required for the other ship to travel from the current time to the decision point. Specifically, the decision point setting unit 14 sets multiple decision points on the predicted route.

[0044] The route setting unit 15 sets a route for the ship to navigate toward a judgment point by maintaining the current ship speed from the ship's heading and position as a starting point, turning at a turning rate, and changing course toward the judgment point, and outputs the route and the ship's travel time to reach the judgment point. Specifically, the route setting unit 15 outputs multiple routes for navigating toward each of the multiple judgment points, and multiple ship's travel times to reach each of the multiple judgment points.

[0045] The risk value calculation unit 16 calculates a collision risk value at a judgment point based on the predicted route and travel time of the other ship, and the route and travel time of the own ship. Specifically, the risk value calculation unit 16 calculates a collision risk value at each of a plurality of judgment points.

[0046] The display control unit 17 displays the OZT at the judgment point where the risk value calculated by the risk value calculation unit 16 is equal to or greater than the threshold value (see Figure 7). Specifically, the display control unit 17 indicates the positions of the ship and other ships in the image displayed on the display unit 2, and places the OZT on the predicted course of the other ships.

[0047] Fig. 6 is a diagram showing an example of the procedure of a ship monitoring method according to an embodiment. The information processing device 1 executes the process shown in the diagram in accordance with a program. Fig. 7 is a diagram showing an example of calculation and display of OZT.

[0048] First, the information processing device 1 acquires the own ship data and other ship data (S11), and acquires the ROT threshold value (S12).

[0049] Next, the information processing device 1 sets decision points on the predicted course of the other ship based on the other ship data (S13: processing as the decision point setting unit 14). Multiple decision points are set at equal intervals on the predicted course of the other ship. The multiple decision points represent the predicted position of the other ship at each point in time every predetermined time period.

[0050] Specifically, the calculation of the other ship's predicted course and the setting of the decision points are performed under the assumption that the other ship will maintain its current speed. In other words, the other ship is assumed to continue sailing with a constant magnitude and direction of its speed vector from its position at the reference time. Therefore, the other ship's predicted course is a straight line extending the ship's speed vector and passing through the other ship's position at the reference time, and multiple decision points are set on that line.

[0051] However, it is also possible to assume that at least one of the speed and direction of the other ship changes over time. In other words, the speed of the other ship does not have to be constant as long as the predicted position of the other ship after a predetermined time has elapsed can be calculated. For example, the speed of the other ship may gradually increase or decrease over time. Furthermore, if route data for the other ship's planned route can be obtained, multiple decision points may be set on the other ship's planned route based on the route data.

[0052] Next, the information processing device 1 calculates a risk value based on the own ship data when the own ship turns and heads toward one of the judgment points (S14: processing as the route setting unit 15 and risk value calculation unit 16). The risk value is expressed, for example, as the probability that the own ship and the other ship will be present at the judgment point at the same time. Alternatively, the risk value may be expressed as the distance between the predicted position of the own ship and the predicted position of the other ship at the same time.

[0053] As shown in Fig. 7, the information processing device 1 calculates the risk value under the assumption that the ship will maintain its speed from its current position to the decision point and turn at a constant ROT that does not exceed the ROT threshold. The ROT increases as the distance between the ship's heading and the decision point increases.

[0054] In other words, the ship reaches the decision point by changing the direction of the ship speed vector by a certain degree from its own position at the reference time while keeping the magnitude of the ship speed vector constant.

[0055] In this example, the ship's route is represented by an arc extending from the ship's current position toward the bow and reaching the decision point, which makes the ship's route longer than the straight line connecting the ship's current position and the decision point.

[0056] Alternatively, as shown in Fig. 8, the information processing device 1 may calculate the risk value under the assumption that the ship will turn from its current position at the ROT threshold and then proceed straight to reach the decision point. In this example, the ship's route is represented by a pair of a circular arc RP and a straight line LP. Note that the turn may be performed at an ROT equal to or less than the ROT threshold.

[0057] In this embodiment, the speed of the ship is assumed to be constant, but this is not limiting and the ship's speed may be assumed to change over time. For example, the ship's speed may gradually increase or decrease over time.

[0058] Next, if the calculated risk value is equal to or greater than the threshold (S15: YES), the information processing device 1 determines the judgment point as an OZT display point (S16). On the other hand, if the calculated risk value is less than the threshold (S15: NO), the information processing device 1 does not determine the judgment point as an OZT display point.

[0059] The information processing device 1 repeats the processes of S14 to S16 above until risk values ​​have been calculated for all decision points (S17: NO), and when risk values ​​have been calculated for all decision points (S17: YES), it outputs the position of the OZT display point and ends the process.

[0060] If there are multiple other ships, the information processing device 1 executes the above-described processes of S13 to S17 for each of the multiple other ships.

[0061] The information processing device 1 displays the OZT at the determined OZT display point (processing as the display control unit 17). A predetermined safe separation distance is used as the radius of the OZT. As shown in Figure 7, in a range where two or more OZT display points are consecutive, the OZT may have a shape extending in the same direction as the predicted course of the other ship, for example, a rounded rectangle with semicircular ends.

[0062] According to the embodiment described above, the collision risk value is calculated assuming that the ship will turn from its current position and current direction and head toward each of multiple decision points on the other ship's predicted course, which improves prediction accuracy and reduces the discrepancy between the area where the OZT is displayed and the area where there is an actual collision risk.

[0063] Fig. 9 is a diagram showing an example of the procedure of a ship monitoring method according to a modified example. Fig. 10 is a diagram for explaining an example of calculating OZT. Configurations or procedures that overlap with those in the above embodiment are given the same numbers, and detailed explanations may be omitted.

[0064] When the information processing device 1 sets decision points on the predicted course of the other ship (S13), it extracts decision points that are within a range that the ship can reach by turning at or below the ROT threshold from the decision points set on the predicted course of the other ship (S23).The information processing device 1 then calculates a risk value for each of the extracted decision points and determines the OZT display point (S14 to S16 and S27).

[0065] On the other hand, the information processing device 1 does not calculate risk values ​​for judgment points set on the predicted course of other ships that are outside the range that the ship can reach by turning below the ROT threshold (judgment points marked with an X in Figure 10).

[0066] That is, as shown in FIG. 10, a risk value is calculated for decision points that are inside a pair of arcs on the left and right that represent the ROT threshold, and a risk value is not calculated for decision points that are outside the pair of arcs on the left and right that represent the ROT threshold.

[0067] This narrows down the decision points for which risk values ​​are calculated to those within the range that the ship can reach by turning at or below the ROT threshold, thereby improving calculation speed and reducing calculation load.

[0068] 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.

[0069] In the above embodiment, the risk value was calculated assuming that the ship will maintain its speed and turn at a predetermined ROT, but this is not limiting. For example, the ship's position may be predicted using parameters that represent the ship's turning performance based on a KT model that takes into account the ship's hull characteristics. This makes it possible to calculate the risk value taking into account the reduction in the ship's speed when turning.

[0070] [Note] The ship monitoring system may include 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 value calculation unit that calculates, based on the first ship data and the second ship data, a risk value that represents the risk of collision between the first ship and the second ship at each of a plurality of judgment points on the second ship's predicted course when it is assumed that the first ship will turn from its current position and direction and head toward each of the plurality of judgment points; and a display unit that displays OZT (Obstacle Zone by Target) at judgment points among the plurality of judgment points where the risk value is above a threshold.

[0071] The risk value calculation unit may calculate the risk value under the assumption that the first vessel will turn at a predetermined ROT (Rate of Turn) or less. The risk value calculation unit may calculate the risk value under the assumption that the first vessel will turn at a constant ROT from its current position to the judgment point. The risk value calculation unit may calculate the risk value under the assumption that the first vessel will turn at the predetermined ROT from its current position and then travel straight to reach the judgment point.

[0072] The risk value calculation unit may use a ROT corresponding to the size of the first vessel as the predetermined ROT. The risk value calculation unit may predict the position of the first vessel using a parameter representing the turning performance of the first vessel.

[0073] Furthermore, the risk value calculation unit may calculate the risk value for each decision point on the predicted course of the second vessel that is within a range that the first vessel can reach by turning at or below the predetermined ROT. The risk value calculation unit may not calculate the risk value for each decision point on the predicted course of the second vessel that is outside a range that the first vessel can reach by turning at or below the predetermined ROT. [Explanation of symbols]

[0074] 1 Information processing device, 2 Display unit, 3 Radar, 4 AIS, 5 GNSS receiver, 6 Gyrocompass, 7 ECDIS, 8 Alarm unit, 11 Risk value calculation unit, 12 Display control unit, 13 Parameter storage unit, 100 Ship monitoring system

Claims

1. a turning information input unit into which the current direction and turning rate of the first vessel are input; a position and vessel speed information input unit for inputting the current position and vessel speed of the first vessel; a second vessel predicted course information input unit into which the current position, vessel speed, and predicted course from the current time onward of the second vessel are input; a decision point setting unit that sets a decision point on the predicted route based on the position, speed, and predicted route of the second vessel, and outputs the position of the decision point and the second vessel travel time required for the second vessel to travel from the current time to the decision point; a route setting unit that sets a route along which the first vessel will navigate toward the judgment point by maintaining the current vessel speed and turning at the turning rate, starting from the heading and position of the first vessel, and changing course toward the judgment point, and outputs the route and the first vessel navigation time required to reach the judgment point; a risk value calculation unit that calculates a collision risk value at the judgment point based on the predicted route and second vessel travel time of the second vessel, and the route and first vessel travel time of the first vessel; A vessel monitoring system comprising:

2. the decision point setting unit sets a plurality of decision points on the predicted course, the route setting unit outputs a plurality of routes for traveling toward the plurality of judgment points, respectively, and a plurality of first vessel traveling times for arriving at the plurality of judgment points, respectively; the risk value calculation unit calculates a collision risk value at each of the plurality of judgment points; The vessel monitoring system of claim 1 .

3. The turning information input unit receives a turning rate equal to or less than a predetermined turning rate.

3. A vessel monitoring system according to claim 1 or 2.

4. the route setting unit sets the route under the assumption that the first vessel will turn at a constant turning rate from its current position to the determination point. The vessel monitoring system according to claim 3 .

5. the risk value calculation unit sets the route under the assumption that the first vessel will turn from its current position at a predetermined turning rate and then travel straight to reach the judgment point. The vessel monitoring system according to claim 3 .

6. the turning information input unit sets the route using a turning rate corresponding to the size of the first vessel.

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

7. the risk value calculation unit calculates the risk value for each judgment point within a range that the first vessel can reach by turning at or below the predetermined turning rate, on the predicted course of the second vessel; The vessel monitoring system according to claim 3 .

8. the risk value calculation unit does not calculate the risk value for each judgment point on the predicted course of the second vessel that is outside a range that the first vessel can reach by turning at or below the predetermined turning rate, 8. A vessel monitoring system according to claim 7.

9. Enter the current heading and rate of turn of the first vessel, inputting the current position and speed of the first vessel; Input the current position, speed and predicted course of the second vessel from the current point in time; setting a judgment point on the predicted route based on the position, speed and predicted route of the second vessel, and outputting the position of the judgment point and a second vessel travel time required for the second vessel to travel from the current time to the judgment point; a route for the first vessel to travel toward the judgment point by maintaining the vessel speed at the current time point, turning at the turning rate, and changing course toward the judgment point, starting from the heading and position of the first vessel; and outputting the first vessel travel time to reach the judgment point and the route; calculating a collision risk value at the judgment point based on the predicted route and second vessel travel time of the second vessel, and the route and first vessel travel time of the first vessel; Ship monitoring method.

10. a turning information input unit into which the current direction and turning rate of the first vessel are input; a position and vessel speed information input unit for inputting the current position and vessel speed of the first vessel; a second vessel predicted course information input unit into which the current position, vessel speed, and predicted course from the current time onward of the second vessel are input; a decision point setting unit that sets a decision point on the predicted route based on the position, speed, and predicted route of the second vessel, and outputs the position of the decision point and the second vessel travel time required for the second vessel to travel from the current time to the decision point; a route setting unit that sets a route along which the first vessel will navigate toward the judgment point by maintaining the current vessel speed and turning at the turning rate, starting from the heading and position of the first vessel, and changing course toward the judgment point, and outputs the route and the first vessel navigation time required to reach the judgment point; a risk value calculation unit that calculates a collision risk value at the judgment point based on the predicted route and second vessel travel time of the second vessel, and the route and first vessel travel time of the first vessel; An information processing device comprising:

11. a turning information input unit for inputting the current direction and turning rate of the first vessel; a position and vessel speed information input unit for inputting the current position and vessel speed of the first vessel; a second vessel predicted course information input unit into which the current position, vessel speed, and predicted course from the current time onward of the second vessel are input; a decision point setting unit that sets a decision point on the predicted route based on the position, speed, and predicted route of the second vessel, and outputs the position of the decision point and the second vessel travel time required for the second vessel to travel from the current time to the decision point; a route setting unit that sets a route along which the first vessel will navigate toward the judgment point by maintaining the current vessel speed and turning at the turning rate, starting from the heading and position of the first vessel, and changing course toward the judgment point, and outputs the route and the first vessel navigation time required to reach the judgment point; and a risk value calculation unit that calculates a collision risk value at the judgment point based on the predicted route and second vessel travel time of the second vessel, and the route and first vessel travel time of the first vessel; A program that allows a computer to function as a

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