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

Abstract

To provide a marine vessel monitoring system capable of improving accuracy of collision risk evaluation.SOLUTION: A marine vessel monitoring system is provided comprising: a first data generation unit configured to generate first marine vessel data representing the position and speed of a first marine vessel; a second data generation unit configured to generate second marine vessel data representing the position and speed of a second marine vessel; a risk value computation unit configured to compute a risk value representing the risk of collision between the first marine vessel and the second marine vessel on the basis of the first marine vessel data and the second marine vessel data; a safety level determination unit configured to determine a safety level of the position of the second marine vessel from a distribution of the safety level determined with respect to the first marine vessel; a risk value adjustment unit configured to adjust the risk value according to the safety level; and an alarm unit configured to issue an alert when the adjusted risk value is greater than or equal to a threshold.SELECTED DRAWING: Figure 3

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] [Non-Patent Document 1] Imazu, Junji Fukuto, Masayoshi Numano, “Obstruction Zones by Other Vessels and Their Indications”, Journal of the Japan Institute of Navigation, Vol. 107, 2002, p. 191-197 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional methods, depending on the conditions, the risk of collision between ships may be assessed as high even if the risk is actually low.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its main objective 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 assessment. [Means for solving the problem]

[0006] In order to solve the above problems, a ship monitoring system of one embodiment 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 value calculation unit that calculates a risk value representing the risk of collision between the first ship and the second ship based on the first ship data and the second ship data, a safety determination unit that determines the safety of the position of the second ship from a distribution of safety levels determined based on the first ship, a risk value adjustment unit that adjusts the risk value according to the safety level, and an alarm unit that issues an alarm if the adjusted risk value is greater than or equal to a threshold value.

[0007] In another aspect of the ship monitoring method of the present invention, a first data generation unit generates first ship data representing a position and speed of a first ship, and a second data generation unit generates second ship data representing a position and speed of a second ship, calculates a risk value representing the risk of collision between the first ship and the second ship based on the first ship data and the second ship data, determines a safety level of the position of the second ship from a distribution of safety levels determined based on the first ship, adjusts the risk value in accordance with the safety level, and issues an alarm if the adjusted risk value is greater than or equal to a threshold value.

[0008] In addition, another aspect of the information processing device of the present invention includes a risk value calculation unit that calculates a risk value representing the risk of collision between the first ship and the second ship based on 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, a safety determination unit that determines the safety of the position of the second ship from a distribution of safety levels determined based on the first ship, a risk value adjustment unit that adjusts the risk value according to the safety level, and an alert determination unit that outputs an alert command to an alarm unit when the adjusted risk value is greater than or equal to a threshold value.

[0009] In addition, another aspect of the program of the present invention causes a computer to calculate a risk value representing the risk of collision between the first ship and the second ship based on 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, determine the safety level of the position of the second ship from a distribution of safety levels determined based on the first ship, adjust the risk value according to the safety level, and output an alert command to an alarm unit if the adjusted risk value is greater than or equal to a threshold value. Effect of the Invention

[0010] According to the present invention, it is possible to improve the accuracy of the assessment of the collision risk. [Brief description 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. [Diagram 2] FIG. 4 is a diagram showing an example of a other ship management database. [Diagram 3] FIG. 1 is a diagram illustrating an example of a configuration of an information processing device according to an embodiment. [Figure 4] FIG. 1 is a diagram for explaining TCPA / DCPA. [Diagram 5] FIG. 1 is a diagram for explaining an SJ value. [Figure 6] 5 is a diagram showing an example of a procedure of a vessel monitoring method according to an embodiment; [Figure 7] FIG. 13 is a diagram showing an example of safety distribution by bow passing. [Figure 8] FIG. 13 is a diagram showing an example of a safety degree distribution by cross passing; [Figure 9] FIG. 13 is a diagram illustrating an example of the configuration of a risk value adjustment unit. [Figure 10] FIG. 13 is a diagram for explaining a safety distribution. [Figure 11] 11 is a diagram showing another example of a procedure of the ship monitoring method according to the embodiment. FIG. [Figure 12] FIG. 13 is a diagram for explaining a matchmaking relationship. [Figure 13]FIG. 13 is a diagram for explaining a matchmaking relationship. [Figure 14] FIG. 13 is a diagram illustrating a modified example of the risk value calculation unit. [Figure 15] FIG. 1 is a diagram for explaining OZT. [Figure 16] FIG. 1 is a diagram for explaining OZT. [Figure 17] FIG. 1 is a diagram for explaining BCR / BCT. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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

[0014] The ship on which the ship monitoring system 100 is installed is an example of a first ship, and will be referred to as "own ship" in the following description. Ships present around the own ship are examples of second ships, and will be referred to as "other ships" in the following description.

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

[0016] The ship 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, a RAM, a ROM, a non-volatile memory, an input / output interface, etc. The CPU of the information processing device 1 executes information processing according to a program loaded from the ROM or the non-volatile 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, without being limited to a touch sensor.

[0020] The radar 3 emits radio waves around the ship and receives the reflected waves, and generates 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 indicates 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. It is not limited to AIS, and VDES (VHF Data Exchange System) may be used. The AIS data includes the positions and speeds of other ships.

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

[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. The warning by display may be issued by the display unit 2. That is, 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] Further, 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 the change in the ship's position over time.

[0028] Alternatively, the ship's speed may be detected based on the ship's direction detected by the gyrocompass 6 and the ship's speed 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 the other ship data. The AIS data generated by the AIS 4 also corresponds to the 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. In the other ship management database, other ship data generated by the radar 3 or the AIS 4 is registered.

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

[0032] 3 is a block diagram showing an example of the configuration of an information processing device 1 according to an embodiment. The information processing device 1 includes a risk value calculation unit 11, a safety level determination unit 12, a risk value adjustment unit 13, and an alarm determination unit 14. These functional units are realized by the CPU of the information processing device 1 executing information processing according to a program.

[0033] The risk value calculation unit 11 calculates a risk value representing the risk of collision between the own ship and another ship based on the own ship data and the other ship data. A known method is used to calculate the risk value. For example, the risk value calculation unit 11 calculates the risk value based on TCPA and DCPA. The risk value calculation unit 11 may also calculate the risk value based on the SJ value.

[0034] FIG. 4 is a diagram for explaining TCPA (Time to Closest Point of Approach) / DCPA (Distance to Closest Point of Approach). A collision warning by TCPA / DCPA is a method of issuing a warning when both TCPA and DCPA are below a threshold.

[0035] With this method, as shown in the figure, the TCPA / DCPA values ​​are the same when another ship approaches in front of the ship and when it approaches from behind the ship, which means that even though the former is actually a greater risk than the latter, the method treats the two risks as being equally dangerous.

[0036] Fig. 5 is a diagram for explaining the SJ (Subject Judgement) value. The SJ value is a value that expresses the subjective collision risk felt by the ship navigator, obtained from test subject data obtained from a ship maneuvering simulator, using a regression equation of the distance to other ships and the rate of change of relative heading.

[0037] In other words, this method tends to calculate a high risk value for other ships that are close and continue to be visible in the same direction. However, as shown in the figure, there is a problem in that the risk value is calculated to be high even for other ships that there is no risk of collision after passing each other.

[0038] Therefore, in this embodiment, the risk value calculated by the risk value calculation unit 11 is adjusted by the safety determination unit 12 and the risk value adjustment unit 13 to improve the accuracy of the risk assessment. A specific method for adjusting the risk value will be described below.

[0039] 6 is a flow diagram showing an example of the procedure of the vessel monitoring method according to this embodiment, which is implemented in the vessel monitoring system 100. The information processing device 1 executes the information processing shown in the diagram according to a program.

[0040] First, the information processing device 1 calculates a risk value indicating the risk of collision between the own ship and another ship by a method such as TCPA / DCPA or SJ value as described above (S11: processing as the risk value calculation unit 11).

[0041] Next, the information processing device 1 determines the safety level of the other ship's position from a safety level distribution determined based on the own ship data and the other ship data. Specifically, the information processing device 1 determines the safety level A based on bow passing and the safety level B based on beam passing (S12, S13: processing as the safety level determination unit 12).

[0042] 7 is a diagram showing an example of safety level distribution by bow passing. In S12, the information processing device 1 sets a safety line parallel to the bow line of the own ship, in the opposite direction to the other ships (i.e., toward the traveling direction or bow direction of the other ships) and a predetermined distance away from the bow line.

[0043] For example, if another ship is located to the right of the bow line and sailing to the left, a safety line is set to the left of the bow line, for example, at a distance five times the ship's width.In this case, the area to the right of the bow line is (a) the danger area, the area between the bow line and the safety line is (b) the caution area, and the area to the left of the safety line is (c) the safety area.

[0044] (a) The safety level of the danger area is set to 0. (b) The safety level of the caution area is set to a value between 0 and 1 and is higher than the safety level of the danger area (a). (c) The safety level of the safety area is set to 1 and is higher than the safety level of the caution area (b).

[0045] (b) The safety level of the caution area may be set to gradually increase as it approaches the safety line, i.e., away from the bow line.

[0046] Then, the information processing device 1 determines in which area the other ship is located: (a) danger area, (b) caution area, or (c) safety area, and applies the safety level corresponding to the relevant area as safety level A for bow passing.

[0047] 8 is a diagram showing an example of safety level distribution by beam passing. In S13, the information processing device 1 sets a safety line parallel to the beam line of the own ship at a predetermined distance away from the beam line of the own ship in the rearward direction (i.e., toward the forward direction or bow direction of the other ship) of the own ship.

[0048] For example, if another ship is located ahead of the ship's beam line and sailing astern, a safety line is set behind the beam line, for example, at a distance five times the ship's overall width.In this case, the area ahead of the beam line is the (a) danger area, the area between the beam line and the safety line is the (b) caution area, and the area behind the safety line is the (c) safety area.

[0049] As above, the safety level of the (a) danger area is set to 0. The safety level of the (b) caution area is set to a value between 0 and 1 and is set higher than the safety level of the (a) danger area. The safety level of the (c) safety area is set to 1 and is set higher than the safety level of the (b) caution area.

[0050] (b) The safety level of the caution area may be set to gradually increase as it approaches the safety line, i.e., away from the bow line.

[0051] Then, the information processing device 1 determines in which area the other ship is located: (a) danger area, (b) caution area, or (c) safety area, and applies the safety degree corresponding to the relevant area as safety degree B for straight passing.

[0052] Returning to the description of Fig. 6, the information processing device 1 then determines the security level based on the security levels A and B determined in the above S12 and S13 (S14: processing as the security level determination unit 12).

[0053] For example, the safety level may be determined by taking the maximum value max(safety level A, safety level B) of safety level A and safety level B. Also, the safety level may be determined by calculating 1-(1-safety level A)(1-safety level B). 1-safety level A represents the negation of safety level A.

[0054] Next, the information processing device 1 adjusts the risk value calculated in the above S11 in accordance with the safety level determined in the above S14 (S15: processing as the risk value adjustment unit 13).

[0055] Specifically, as shown in Fig. 9, the risk value adjustment unit 13 includes a coefficient conversion unit 131 and an AND operation unit 132. The coefficient conversion unit 131 outputs a value obtained by subtracting the safety level (a value between 0 and 1) from 1. The AND operation unit 132 adjusts the risk value by multiplying the risk value by the value obtained by subtracting the safety level from 1. That is, the AND operation unit 132 performs an AND operation on the value of 1 - the safety level and the risk value. Without being limited thereto, the AND operation unit 132 may take the minimum value of the value of 1 - the safety level and the risk value.

[0056] Next, the information processing device 1 determines whether the risk value adjusted in S15 above is equal to or greater than a threshold, and if the adjusted risk value is equal to or greater than the threshold, outputs an alert command to the alarm unit 8 (S16, S17: processing as the alarm command determination unit 14). Upon receiving the alert command, the alarm unit 8 issues an alert.

[0057] The issuance of an alarm is realized, for example, by highlighting the other ship's symbol by changing its color, blinking it, or adding a frame indicating that it is the subject of an alarm on the display unit 2 that also serves as the alarm unit 8. In this case, the alarm command is a display command for highlighting the other ship's symbol.

[0058] According to the embodiment described above, it is possible to prevent a situation in which an alarm is issued even when the risk of a collision between the ship and another ship is actually low, and thus it is possible to prevent a situation in which false alarms occur frequently in congested sea areas.

[0059] [First Modification] 10, when the other ship is proceeding, even though the distance between the ship and the other ship is still close, in the above embodiment, the other ship has exceeded the safety line in the bow direction, and the safety level is maximized. Therefore, in this modified example, the meeting relationship between the ship and the other ship is judged and the safety level is determined taking the meeting relationship into consideration, as described below.

[0060] 11 is a flow chart showing an example of the procedure of the ship monitoring method according to this modification. The same steps as those in the above embodiment are denoted by the same reference numbers, and detailed explanations thereof may be omitted.

[0061] When the information processing device 1 determines the safety levels A and B (S12, S13), it determines the matching relationship between the own ship and the other ship based on the own ship data and the other ship data (S21).

[0062] As shown in Figure 12, the encounter relationship includes, for example, overtaking, crossing to the right, crossing to the left, meeting (going in the opposite direction), and running side by side. The direction and magnitude of the relative velocity vector between the ship's velocity vector and the other ship's velocity vector determine which encounter relationship the ship belongs to. The figure shows an example where a ship is determined to be crossing to the right.

[0063] The information processing device 1 determines a security level from the security level distribution according to the determined matched relationship (S22), and adjusts a risk value according to the security level (S15).

[0064] Specifically, when the match relationship is crossing (right crossing or left crossing), the information processing device 1 determines the safety degree A based on the safety degree distribution by bow passing (see FIG. 7) as the safety degree. Without being limited to this, the safety degree A may be applied preferentially, for example, by increasing the weight of the safety degree A.

[0065] On the other hand, when the meeting relationship is a passing encounter, the information processing device 1 determines the safety degree B based on the safety degree distribution (see FIG. 8) by passing directly across as the safety degree. Without being limited to this, the safety degree B may be applied preferentially by increasing the weight of the safety degree B, for example.

[0066] When the matchmaking relationship is other than crossing or meeting, the information processing device 1 determines the safety degree in the same manner as in S14 of the above embodiment.

[0067] In addition, within the boundary range of the match relationship, it is preferable to gradually change the degree of safety in accordance with changes in the course difference (the direction of the relative speed vector with respect to the ship's own heading).

[0068] For example, as shown in Fig. 13, a heading difference of 160 degrees or less is considered to be a crossing, a heading difference of 170 degrees or more is considered to be a passing, and the range in between is considered to be a boundary range. The suitability of a crossing gradually decreases from 1 to 0 as the heading difference increases from 160 degrees to 170 degrees in the boundary range. The suitability of a passing gradually increases from 0 to 1 as the heading difference increases from 160 degrees to 170 degrees in the boundary range.

[0069] By determining the degree of safety based on this degree of compatibility, it is possible to gradually change the degree of safety within the boundary range of the matching relationship, thereby making it possible to suppress the degree of safety from over-reacting to noise in ship speed or position (so-called chattering).

[0070] Specifically, when the course difference is within the boundary range, the safety degree A based on the safety degree distribution by bow passing (see Figure 7) is multiplied by the suitability of crossing to correct the safety degree A. Also, when the course difference is within the boundary range, the safety degree B based on the safety degree distribution by beam passing (see Figure 8) is multiplied by the suitability of passing to correct the safety degree B.

[0071] For example, if the compatibility degree of crossing is 0.7 and the compatibility degree of meeting is 0.3, the safety degree is determined to be the sum of the value obtained by multiplying the safety degree A by 0.7 and the value obtained by multiplying the safety degree B by 0.3. The safety degree may be calculated in the same manner as described in paragraphs 0053 to 0055 above.

[0072] [Second modified example] In the above embodiment, the risk value was calculated by a method using TCPA / DCPA or SJ value, etc., but this is not limited to this. The risk value may be calculated based on OZT, BCR, and BCT, as in the modified example described below.

[0073] 14 is a diagram showing a modified example of the risk value calculation unit 11. The risk value calculation unit 11 includes an OZT calculation unit 111, a BCR / BCT calculation unit 112, and a synthesis unit 113.

[0074] Fig. 15 is a diagram for explaining OZT (Obstacle Zone by Target). OZT is a zone where the navigation of the ship is obstructed by other ships, and is displayed on the planned course of the other ship. When the extension line of the ship's speed vector intersects with the OZT and the arrival time to the OZT is less than a threshold, it is evaluated that there is a high risk of collision with the other ship.

[0075] Incidentally, as shown in Figure 16, even if the extension of the ship's speed vector does not intersect with the OZT and the risk of collision with another ship is assessed to be low, it is preferable to issue an alarm to alert the ship if another ship crosses in front of the ship at a close distance within a short period of time.

[0076] Therefore, in this modification, the risk assessment by the OZT calculation unit 111 and the risk assessment by the BCR / BCT calculation unit 112 are combined by the synthesis unit 113.

[0077] FIG. 17 is a diagram for explaining BCR (Bow Crossing Range) and BCT (Bow Crossing Time). BCT is the predicted time until another ship crosses the bow line of the own ship. BCR is the predicted distance from the own ship to the other ship when the other ship crosses the bow line of the own ship.

[0078] BCR and BCT are indicators suitable for evaluating "when another ship crosses in front of your ship in a short time." Note that BCR has a positive and negative sign in reverse ahead of your ship, so unlike the TCPA / DCPA mentioned above, it can evaluate the risk ahead of your ship.

[0079] For example, the OZT calculation unit 111 outputs (A) the direction of occurrence of the OZT and (B) the arrival time to the OZT as an index representing the collision risk of the ship colliding with another ship. In addition, (C) the collision probability at the OZT may be output.

[0080] On the other hand, the BCR / BCT calculation unit 112 outputs (iv) BCR and (v) BCT as indices representing the crossing risk of another ship crossing ahead of the ship.

[0081] The synthesis unit 113 calculates an overall risk value that takes into account both the collision risk and the crossing risk based on the above (A) to (E). For example, fuzzy inference is used to calculate such an overall risk value. The risk value is expressed as a value between 0 and 1, for example.

[0082] Here, the parameters of the synthesis unit 113 are adjusted so that the contribution of OZT to the risk value is higher than the contributions of BCR and BCT. For example, when the OZT occurrence direction is close to the ship's course or the arrival time to OZT is short, a high-level risk value is output, and when the BCR is close or the BCT is short, a medium-level risk value is output.

[0083] According to this modified example, not only is an alarm issued when there is a high risk of collision between one's ship and another ship, but an alarm can also be issued to call attention to another ship if it passes close in front of the ship within a short period of time.

[0084] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made by those skilled in the art. [Explanation of symbols]

[0085] 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 Safety degree judgment unit, 13 Risk value adjustment unit, 100 Ship monitoring system, 131 Coefficient conversion unit, 132 and calculation unit, 14 Alert judgment unit, 111 OZT calculation unit, 112 BCR / BCT calculation unit, 113 Synthesis unit

Claims

1. a first data generation unit that generates first vessel data representing a position and a velocity of the first vessel; a second data generation unit that generates second vessel data representing a position and a velocity of the second vessel; a risk value calculation unit that calculates a risk value representing a risk of a collision between the first vessel and the second vessel based on the first vessel data and the second vessel data; a safety level determination unit that determines a safety level of the position of the second vessel from a distribution of safety levels determined based on the first vessel; a risk value adjustment unit that adjusts the risk value according to the degree of safety; an alarm unit that issues an alarm when the adjusted risk value is equal to or greater than a threshold; Equipped with the safety determination unit defines a first direction as a direction in which the second vessel is located relative to a bow line of the first vessel, and a second direction as an opposite direction to the first direction, sets a safety line that is located in the second direction relative to the bow line and extends in the same direction as the bow line, and sets a safety level of an area located in the second direction relative to the safety line higher than a safety level of an area located in the first direction. Ship monitoring system.

2. the safety determination unit defines a direction in which the second vessel is located relative to a bow line of the first vessel as a first direction, and defines an opposite direction as a second direction, among the lateral directions of the first vessel, and sets a safety level of an area located in the second direction relative to the bow line higher than a safety level of an area located in the first direction. The vessel monitoring system according to claim 1 .

3. The safety determination unit increases a safety level in a region between the bow line and the safety line as the vessel advances in the second direction. The vessel monitoring system of claim 1 .

4. the safety determination unit sets a safety level of an area located aft of the beam line of the first vessel to be higher than a safety level of an area located forward of the beam line of the first vessel, The vessel monitoring system of claim 1 .

5. A first data generation unit that generates first ship data representing a position and a velocity of a first ship; a second data generation unit that generates second vessel data representing a position and a velocity of the second vessel; a risk value calculation unit that calculates a risk value representing a risk of a collision between the first vessel and the second vessel based on the first vessel data and the second vessel data; a safety level determination unit that determines a safety level of the position of the second vessel from a distribution of safety levels determined based on the first vessel; a risk value adjustment unit that adjusts the risk value according to the degree of safety; an alarm unit that issues an alarm when the adjusted risk value is equal to or greater than a threshold; Equipped with the safety level determination unit sets a safety line located aft of the first vessel and extending in the same direction as the beam line of the first vessel, and sets a safety level of an area located aft of the safety line to be higher than a safety level of an area located forward of the safety line. Ship monitoring system.

6. the safety level determination unit increases the safety level in a region between the lateral line and the safety line toward the rear, A vessel monitoring system according to claim 5.

7. the safety determination unit determines a safety of the position of the second vessel according to a matching relationship between the first vessel and the second vessel.

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

8. the safety level determination unit gradually changes the safety level in accordance with a change in the relative direction between the first vessel and the second vessel within a boundary range of the match relationship. A vessel monitoring system according to claim 7.

9. The risk value calculation unit calculates the risk value based on a time to closest point of approach (TCPA) and a distance to closest point of approach (DCPA).

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

10. The risk value calculation unit calculates the risk value based on a Subject Judgment (SJ) value.

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

11. The risk value calculation unit calculates the risk value based on an OZT (Obstacle Zone by Target), a BCR (Bow Crossing Range), and a BCT (Bow Crossing Time). A vessel monitoring system according to any one of claims 1 to 10.

12. A first data generation unit that generates first ship data representing a position and a velocity of a first ship; a second data generation unit that generates second vessel data representing a position and a velocity of the second vessel; a risk value calculation unit that calculates a risk value representing a risk of a collision between the first vessel and the second vessel based on the first vessel data and the second vessel data; a safety level determination unit that determines a safety level of the position of the second vessel from a distribution of safety levels determined based on the first vessel; a risk value adjustment unit that adjusts the risk value according to the degree of safety; an alarm unit that issues an alarm when the adjusted risk value is equal to or greater than a threshold; Equipped with The risk value calculation unit calculates the risk value based on an OZT (Obstacle Zone by Target), a BCR (Bow Crossing Range), and a BCT (Bow Crossing Time). The risk value calculation unit sets the contribution of OZT to the risk value higher than the contributions of BCR and BCT. Ship monitoring system.

13. The first data generation unit is installed on the first ship and includes a GNSS receiver that detects the position of the first ship based on radio waves received from a Global Navigation Satellite System (GNSS). A vessel monitoring system according to any one of claims 1 to 12.

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

15. A first data generation unit generates first ship data representing a position and a velocity of the first ship; A second data generation unit generates second ship data representing a position and a velocity of the second ship; Calculating a risk value representing a risk of a collision between the first vessel and the second vessel based on the first vessel data and the second vessel data; determining a safety level of the position of the second vessel from a distribution of safety levels determined based on the first vessel; Adjusting the risk value according to the degree of safety; If the adjusted risk value is equal to or greater than a threshold, an alarm is issued. A vessel monitoring method, comprising: The determination of the safety level is performed by defining a direction in which the second vessel is located relative to a bow line of the first vessel as a first direction, and defining the opposite direction as a second direction, and setting a safety line that is located in the second direction relative to the bow line and extends in the same direction as the bow line, and setting a safety level of an area located in the second direction relative to the safety line higher than a safety level of an area located in the first direction. Ship monitoring methods.

16. a risk value calculation unit that calculates a risk value that represents a risk of a collision between the first vessel and the second vessel based on first vessel data that represents a position and a speed of a first vessel and second vessel data that represents a position and a speed of a second vessel; a safety level determination unit that determines a safety level of the position of the second vessel from a distribution of safety levels determined based on the first vessel; a risk value adjustment unit that adjusts the risk value according to the degree of safety; an alarm determination unit that outputs an alarm command to an alarm unit when the adjusted risk value is equal to or greater than a threshold; Equipped with the safety determination unit defines a first direction as a direction in which the second vessel is located relative to a bow line of the first vessel, and a second direction as an opposite direction to the first direction, sets a safety line that is located in the second direction relative to the bow line and extends in the same direction as the bow line, and sets a safety level of an area located in the second direction relative to the safety line higher than a safety level of an area located in the first direction. Information processing device.

17. calculating a risk value representing a risk of a collision between the first vessel and the second vessel based on first vessel data representing a position and a speed of a first vessel and second vessel data representing a position and a speed of a second vessel; determining a safety level of the position of the second vessel from a distribution of safety levels determined based on the first vessel; Adjusting the risk value according to the degree of safety; and outputting an alarm command to an alarm unit when the adjusted risk value is equal to or greater than a threshold value; Run the following on your computer: The determination of the safety level is performed by defining a direction in which the second vessel is located relative to a bow line of the first vessel as a first direction, and defining the opposite direction as a second direction, and setting a safety line that is located in the second direction relative to the bow line and extends in the same direction as the bow line, and setting a safety level of an area located in the second direction relative to the safety line higher than a safety level of an area located in the first direction. program.

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