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

Abstract

The present application provides a ship monitoring system that easily determines whether a ship passes in front of or behind another ship. The ship monitoring system includes a first estimation unit that estimates, based on a first calculation formula, a predicted position of a first ship in each direction after a first time, assuming that the first ship changes a course in an arbitrary direction at a current position and travels, from first ship data indicating a position and a speed of the first ship; a second estimation unit that estimates, based on a second calculation formula, a predicted course of a second ship and a predicted position of the second ship after a second time included in the predicted course, from second ship data indicating a position and a speed of the second ship; and a passing determination unit that determines, as a range in which the first ship passes in one of front and rear of the second ship, a side closer to a current position of the second ship than a coincidence point at which the predicted position of the first ship and the predicted position of the second ship coincide when the first time and the second time are equal, and determines, as a range in which the first ship passes in the other of front and rear of the second ship, a side farther from the current position of the second ship than the coincidence point.

Description

Technical Field

[0001] This invention relates to ship surveillance systems, ship surveillance methods, information processing devices, and programs. Background Technology

[0002] In the past, there have been various methods for assessing the risk of collisions between ships. For example, Non-Patent Document 1 discloses a method for displaying OZT (Obstacle Zone by Target).

[0003] Existing technical documents

[0004] Patent documents

[0005] Non-patent literature 1: Hayato Imatsu, Junji Fukuto, and Masayoshi Numano, “On the Obstruction Zone Caused by the Other Vessel and Its Display”, Proceedings of the Japan Navigation Society, 2002, Vol. 107, pp. 191-197. Summary of the Invention

[0006] The problem the invention aims to solve

[0007] However, in the method of displaying OZT, the range in the predicted course of another vessel that does not display OZT represents the range within which the vessel can navigate. However, for such a range, it is difficult at first glance to determine whether the vessel is passing in front of or behind another vessel.

[0008] The present invention was made in view of the above-mentioned problems, and its main objective is to provide a ship monitoring system, ship monitoring method, information processing device and program that makes it easy to determine whether a ship is passing in front of or behind another ship.

[0009] means for solving problems

[0010] To address the aforementioned issues, one aspect of the ship monitoring system of the present invention comprises: a first estimation unit that, based on a first calculation formula, estimates the predicted positions of the first ship in each direction after a first time, assuming the first ship changes course in any direction and sails from its current position, according to first ship data representing the position and speed of a first ship; a second estimation unit that, based on a second calculation formula, estimates the predicted course of the second ship and the predicted position of the second ship after a second time, including the predicted course, according to second ship data representing the position and speed of a second ship; and a determination unit that determines the range in the predicted course of the second ship that is closer to the current position of the second ship than the predicted position of the first ship when the first time and the second time are equal, as the range in front of or behind the second ship, and determines the range in the predicted course that is further away from the current position of the second ship, as the range in front of or behind the second ship.

[0011] Furthermore, another aspect of the ship monitoring system of the present invention includes: 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 first estimation unit that, based on the first ship data, creates a first calculation formula representing the predicted position of the first ship in each direction after a first time, assuming the first ship changes course in any direction from its current position and sails; a second estimation unit that, based on the second ship data, creates a second calculation formula representing the predicted position of the second ship after a second time; and a determination unit that, based on a solution of a simultaneous equation including the first and second calculation formulas under the condition that the second time is greater than the first time or the second time is less than the first time, determines the range in the predicted course of the second ship represented by the second calculation formula where the first ship passes in front of the second ship and the range where the first ship passes behind the second ship.

[0012] Furthermore, another aspect of the ship monitoring method of the present invention, based on a first calculation formula, estimates the predicted position of the first ship in each direction after a first time, assuming the first ship changes course in any direction and sails from its current position, based on first ship data representing the position and speed of the first ship. Based on a second calculation formula, estimates the predicted course of the second ship and the predicted position of the second ship after a second time, including the predicted course, based on second ship data representing the position and speed of the second ship. The side of the predicted course of the second ship that is closer to the current position of the second ship than the predicted position of the first ship when the first time and the second time are equal is determined to be the range in which the first ship passes in front of or behind the second ship. The side that is farther away from the current position of the second ship than the predicted position of the second ship is determined to be the range in which the first ship passes in front of or behind the second ship.

[0013] Furthermore, another aspect of the information processing apparatus of the present invention includes: a first estimation unit that, based on a first calculation formula, estimates the predicted positions of the first vessel after a first time in each direction, assuming the first vessel changes course in any direction and sails from its current position, according to first vessel data representing the position and speed of the first vessel; a second estimation unit that, based on a second calculation formula, estimates the predicted course of the second vessel and the predicted position of the second vessel after a second time, including the predicted course, according to second vessel data representing the position and speed of the second vessel; and a determination unit that determines the range in the predicted course of the second vessel that is closer to the current position of the second vessel than the predicted position of the first vessel when the first time and the second time are equal, as the range in front of or behind the second vessel, and determines the range in the predicted course that is further away from the current position of the second vessel than the predicted position of the first vessel, as the range in front of or behind the second vessel.

[0014] Furthermore, another aspect of the present invention causes a computer to perform the following steps: based on a first calculation formula, estimating the predicted position of the first vessel after a first time in each direction, assuming the first vessel changes course and sails in any direction from its current position, based on first vessel data representing the position and speed of the first vessel; based on a second calculation formula, estimating the predicted course of the second vessel and the predicted position of the second vessel after a second time, including the predicted course, based on second vessel data representing the position and speed of the second vessel; and determining the range in the predicted course of the second vessel that is closer to the current position of the second vessel than the predicted position of the first vessel when the first time and the second time are equal, which is the range in the first vessel passing in front of or behind the second vessel; and determining the range in the predicted course of the second vessel that is further away from the current position of the second vessel than the predicted position of the first vessel passing in front of or behind the second vessel, which is the range in the first vessel passing in front of or behind the second vessel.

[0015] The effects of the invention

[0016] According to the present invention, it is easy to determine whether a vessel is passing in front of or behind another vessel. Attached Figure Description

[0017] Figure 1 This is a diagram illustrating an example of the configuration of a ship surveillance system according to an implementation method.

[0018] Figure 2 This is a diagram illustrating an example of a database for managing other ships.

[0019] Figure 3 This is a diagram showing an example (previous example) of OZT.

[0020] Figure 4 This is a diagram illustrating an example of the configuration of an information processing apparatus according to an embodiment.

[0021] Figure 5 It is a diagram used to illustrate the calculation.

[0022] Figure 6 It is a diagram used to illustrate the calculation.

[0023] Figure 7 This is a diagram representing a display example.

[0024] Figure 8 This is a diagram representing other display examples. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] Figure 1This is a block diagram illustrating an example configuration of a ship surveillance system 100 according to an embodiment. The ship surveillance system 100 is a system mounted on a ship and used to monitor ships present in the surrounding area.

[0027] The vessel equipped with the vessel surveillance system 100 is an example of a first vessel, referred to as "this vessel" in the following description. Additionally, the vessel existing around this vessel is an example of a second vessel, referred to as "other vessel" in the following description.

[0028] Additionally, in the following explanation, "speed" is a vector representing rate and bearing (the so-called ship speed vector), and "rate" is a scalar.

[0029] The ship surveillance system 100 includes an information processing unit 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 can be connected to a network N, such as a LAN, and can communicate with each other via the network.

[0030] Information processing device 1 is a computer including a CPU, RAM, ROM, non-volatile memory, and input / output interfaces. The CPU of information processing device 1 executes information processing according to a program loaded from ROM or non-volatile memory into RAM.

[0031] The program can be provided, for example, via information storage media such as optical discs or memory cards, or via communication networks such as the Internet or LAN.

[0032] Display unit 2 is, for example, a display device with a touch sensor. The touch sensor detects the position of a finger or other pointer within the screen. It is not limited to a touch sensor; the pointer position can also be input via a trackball or similar device.

[0033] Radar 3 emits radio waves around the ship and receives the reflected waves, generating echo data based on the received signals. Additionally, Radar 3 identifies objects based on the echo data and generates target tracking data (TT data) representing the position and velocity of the target.

[0034] The AIS (Automatic Identification System) receives AIS data from other vessels or land-based control systems in the vicinity of the vessel. It is not limited to AIS; VDES (VHF Data Exchange System) can also be used. AIS data includes the position and speed of other vessels, etc.

[0035] GNSS receiver 5 detects the ship's position based on radio waves received from GNSS (Global Navigation Satellite System). Gyrocompass 6 detects the ship's bearing. It is not limited to a gyrocompass; a GPS compass or magnetic compass can also be used.

[0036] The CDIS (Electronic Chart Display and Information System) 7 obtains the vessel's position from the GNSS receiver 5 and displays it on the electronic chart. Additionally, the ECDIS 7 also displays the vessel's planned route on the electronic chart. It is not limited to ECDIS; a GNSS plotter can also be used.

[0037] Alarm unit 8 issues an alarm when there is a risk of collision between the vessel and another vessel. Alarm unit 8 can be a display-based alarm, or an audible or visual alarm. Display-based alarms can be issued from display unit 2. That is, display unit 2 can also function as alarm unit 8.

[0038] In this embodiment, the information processing device 1 is a standalone device, but it is not limited to this and can also be integrated with other devices such as ECDIS7. That is, the functional parts of the information processing device 1 can also be implemented by other devices such as ECDIS7.

[0039] In addition, the display unit 2 is also a separate device, but it is not limited to this. The display units of other devices such as ECDIS7 can also be used as the display unit 2 to display images generated by the information processing device 1.

[0040] In this embodiment, the group consisting of GNSS receiver 5 and ECDIS 7 is an example of a first data generation unit, which generates ship data representing the ship's position and speed. Specifically, GNSS receiver 5 detects the ship's position, and ECDIS 7 detects the ship's speed based on the time-varying changes in the ship's position.

[0041] Not limited to this, the ship's speed can also be detected based on the ship's bearing detected by the gyrocompass 6 and the ship's speed detected by the speedometer (not shown).

[0042] Additionally, radar 3 or AIS 4 is an example of a second data generation unit that generates data indicating the position and speed of other vessels. Specifically, the TT data generated by radar 3 is equivalent to other vessel data. Similarly, the AIS data generated by AIS 4 is also equivalent to other vessel data.

[0043] Figure 2This diagram illustrates an example of a foreign vessel management database built in the memory of information processing device 1. The foreign vessel management database contains foreign vessel data generated by radar 3 or AIS 4.

[0044] The database for managing other vessels includes fields such as "other vessel identification," "position," "speed," and "bearing." Furthermore, the positions and bearings of other vessels detected by radar 3 are converted to the same coordinate system as GNSS.

[0045] Figure 3 This is a diagram showing an example (previous example) of OZT. OZT is the area where the vessel's navigation is obstructed by another vessel, shown on the other vessel's predicted course.

[0046] However, the range GP in the predicted course of another vessel, which does not show OZT, is the range that this vessel can navigate. At first glance, it is difficult to determine whether this vessel is ahead of or behind another vessel.

[0047] Therefore, in this embodiment, as described below, it is determined whether the vessel is passing in front of or behind another vessel and displayed accordingly.

[0048] Figure 4 This is a block diagram illustrating an example configuration of the information processing apparatus 1 according to an embodiment. The information processing apparatus 1 includes a first estimation unit 11, a second estimation unit 12, a pass determination unit 13, and a display control unit 14. These functional units are implemented by the CPU of the information processing apparatus 1 executing information processing according to a program.

[0049] The steps of the ship monitoring method in the embodiment are implemented by a first estimation unit 11, a second estimation unit 12, a decision unit 13, and a display control unit 14.

[0050] Figure 5 This diagram illustrates the calculations based on the first estimation unit 11, the second estimation unit 12, and the determination unit 13.

[0051] The first estimation unit 11, based on the first calculation formula (hereinafter also referred to as the first formula), estimates, according to the ship's data, the first time t in each direction when the ship changes course and sails in any direction from its current position. O After (t=t) O The predicted position of the ship. Specifically, the first estimation unit 11 creates a representation indicating the position after the first time t as described below. O After (t=t) O The first formula for the predicted position of this ship. The predicted position of this ship is represented by coordinates (x, y) in the xy plane. The initial position of this ship at t=0 is the origin of the xy plane. Assume that this ship is maintaining a speed v OWhen the ship can instantly rotate in all directions under the given state, its predicted position is as shown in the first equation below, using a radius v centered on the origin. O t O The formula for a circle is given.

[0052] First Form

[0053] The second estimation unit 12, based on the second calculation formula (hereinafter also referred to as the second formula), estimates the predicted course of the other vessel and the elapsed second time t included in the predicted course, according to the data of the other vessel. T After (t=t) T The predicted position of the other ship. Specifically, the second estimation unit 12 creates a representation after the second time t as follows. T After (t=t) T The second equation is used to predict the position of the other ship. The predicted position of the other ship is represented by coordinates (x, y) in the xy-plane. The initial position of the other ship at t=0 is (x0, y0). Assuming the other ship is traveling straight while maintaining its velocity, its predicted position is expressed as a linear function as shown in the second equation below. Tx The x-component of the speed of the other ship. Ty The y-component is the speed of his ship.

[0054] Second Form

[0055] The determination unit 13 determines the "range of passage ahead of another vessel" when the vessel passes ahead of another vessel and the "range of passage behind another vessel" when the vessel passes behind another vessel, based on the first and second formulas described above.

[0056] The determination unit 13 will determine the predicted course of the other ship, expressed by the second formula, compared to the first time t. O With the second time t T When they are equal (t) O =t T If the predicted position of the ship is consistent with the predicted position of the other ship at the points P1 and P2 (i.e., the intersection points P1 and P2 of the circle in the first equation and the straight line in the second equation), and the side that is closer to the current position (initial position x0, y0) of the other ship is determined to be the range that the ship passes in front of or behind the other ship, the side that is further away from the current position of the other ship will be determined to be the range that the ship passes in front of or behind the other ship.

[0057] Specifically, the determination unit 13 determines the side that is closer to the current position of the other ship than the first point of agreement P1 from the current position of the other ship as the "passing range behind the other ship", and determines the side that is farther away from the current position of the other ship than the point of agreement P1 as the "passing range in front of the other ship".

[0058] In addition, the determination unit 13 determines the side that is closer to the current position of the other ship than the second point of agreement P2 from the current position of the other ship as the "passing range in front of the other ship", and determines the side that is farther away from the current position of the other ship than the point of agreement P2 as the "passing range behind the other ship".

[0059] Furthermore, the determination unit 13 determines the defined area including the points of agreement P1 and P2 as a risk area where there is a risk of collision between the vessel and another vessel. The risk area may be, for example, an OZT (Obstacle Zone by Target). However, it is not limited to this; the risk area may also be a PAD (Predicted Area of ​​Danger), etc.

[0060] For OZT calculation, a risk value representing the risk of collision between the vessel and another vessel is calculated, assuming that the vessel changes course in any direction from its current position while maintaining speed, and that the other vessel is also maintaining speed from its current position. This assumption is common to the first and second equations described above; therefore, the calculation of OZT can be partially shared with the calculations of the forward and aft passage ranges described above.

[0061] As described below, the determination unit 13 determines the time based on the second time t. T Compared to the first time t O Large conditions or second time t T Compared to the first time t O Under small conditions, the solution of the simultaneous equations including the first and second equations is used to determine the "range of passage in front of other ships" and the "range of passage behind other ships".

[0062] Using arbitrarily set real numbers a, b, and c (a < b < c), the first time t O With the second time t T The relationship is defined as shown in the third and fourth equations below. Here, b is preferably 0, but it can also be a value close to 0.

[0063] Third Form Fourth Form The "range of passage behind other ships" is determined based on the solution of the combined equations of the first, second, and third equations mentioned above.

[0064] If for t T Solving the first and second equations, we obtain the following equation (1).

[0065] (1)

[0066] Based on equation (1) and equation (3), we obtain equations (2) and (3) below.

[0067] ≥0 (2) <0 (3) Equations (2), (3), and t T The common part ≥0 multiplied by The obtained range is the "range of passage behind other ships" where the ship passes behind the other ship. Let t be the range. T ≥0 is used to exclude the past.

[0068] On the other hand, the "range in front of other ships" is determined based on the solution of the combined equations of the first, second and fourth equations mentioned above.

[0069] If for t T Solving the first and second equations yields the above equation (1).

[0070] Based on equation (1) and equation (4), we obtain equation (4) and equation (5).

[0071] ≥0 (4) <0 (5) Multiply the common part of equations (4), (5), and tT≥0 by The obtained range is the "range in front of other ships" where this ship passes in front of other ships. Let t be the range in front of other ships. T ≥0 is used to exclude the past.

[0072] Figure 6 This is a diagram showing the calculation results of the forward passage range and the rear passage range of other vessels based on the passage determination unit 13. As shown in the diagram, the forward passage range of other vessels is formed inside the circle representing the predicted position of the vessel, and the rear passage range of other vessels is formed outside the circle.

[0073] Specifically, a passageway behind the other ship is formed on the side closer to the other ship's current position than the first point of agreement P1 from the other ship's current position, and a passageway in front of the other ship is formed on the side farther from the other ship's current position than the point of agreement P1.

[0074] Additionally, a passageway in front of the other vessel is formed on the side closer to the other vessel's current position than the second point of agreement P2 from the other vessel's current position, and a passageway behind the other vessel is formed on the side farther from the other vessel's current position than the point of agreement P2.

[0075] Here, in the third equation above, c is set as the upper limit, so the range Gc in which other ships arrive at |c| earlier than our ship (i.e., the area with a sufficiently large time difference of arrival) is excluded from the range behind other ships. It should be noted that when c is set to ∞, the entire range outside the circle in the predicted course of other ships in the first equation is the range behind other ships.

[0076] Furthermore, in the fourth equation above, 'a' is set as a lower limit, thus excluding the area Ga where the ship arrives at |a| earlier than other ships (i.e., the area with a sufficiently large time difference of arrival) from the range in front of other ships. It should be noted that when 'a' is set to -∞, the entire range outside the circle in the predicted course of other ships in the first equation is the range in front of other ships.

[0077] According to the calculation method of this embodiment, since it is not necessary to calculate for each decision point as in calculating OZT, the theoretical resolution of "the range in front of other ships" and "the range behind other ships" can be set to infinitesimal, and the amount of calculation can be suppressed.

[0078] The display control unit 14 generates a display image based on the "passage range in front of other ships" and "passage range behind other ships" determined by the passage determination unit 13, and outputs it to the display unit 2.

[0079] Figure 6 This diagram illustrates an example of the display image shown in display unit 2. In the display image, OZT (or equivalent units of measurement) indicating a risk of collision with another vessel exceeding a threshold is displayed along the predicted course of that vessel. Furthermore, the "range ahead of the other vessel" and the "range behind the other vessel" are displayed along the predicted course of that vessel. The predicted course of the other vessel is shown using auxiliary lines, such as dashed lines.

[0080] The display method, such as changing the color or texture, can be used to identify and display the area in front of and behind other ships, making it easy to identify at a glance. Furthermore, strings can be appended to the "area in front of and behind other ships" for easier identification.

[0081] The passageways ahead of and behind other vessels have a prescribed width and are formed as a band extending along the predicted course of the other vessel. The width of the passageways ahead of and behind other vessels is narrower than the width of the OZT.

[0082] At least one of the forward and aft passage ranges of another vessel is displayed overlapping with the OZT. For example, the forward and aft passage ranges of another vessel can be configured on the OZT or under a semi-transparently formed OZT. It should be noted that, as Figure 8 As shown, OZT can also be omitted.

[0083] According to the implementation method described above, the "passage range in front of other vessels" and the "passage range behind other vessels" are displayed, so it is easy to determine at a glance whether the vessel is in front of or behind other vessels.

[0084] The above describes the embodiments of the present invention. The present invention is not limited to the embodiments described above, and those skilled in the art can make various modifications.

[0085] Explanation of reference numerals in the attached figures

[0086] 1 Information processing unit; 2 Display unit; 3 Radar; 4 AIS; 5 GNSS receiver; 6 Gyrocompass; 7 ECDIS; 8 Alarm unit; 11 First estimation unit; 12 Second estimation unit; 13 Passage determination unit; 14 Display and control unit; 100 Ship surveillance system

Claims

1. A ship surveillance system, wherein, have: The first estimation unit, based on the first calculation formula, estimates the predicted positions of the first vessel in each direction after a first time, assuming that the first vessel changes course and sails in any direction from its current position, according to the first vessel data representing the position and speed of the first vessel. The second estimation unit, based on the second calculation formula, estimates the predicted course of the second vessel and the predicted position of the second vessel after a second time, based on the second vessel data representing the position and speed of the second vessel. as well as The determination unit determines the range in which the first ship passes in front of or behind the second ship if the predicted position of the first ship is closer to the current position of the second ship than the predicted position of the second ship when the first time and the second time are equal. The determination unit determines the range in which the first ship passes in front of or behind the second ship if the predicted position of the second ship is closer to the current position of the second ship than the predicted position of the first ship.

2. The ship surveillance system as described in claim 1, wherein, The passage determination unit will determine the range in which the first vessel passes behind the second vessel if the first point of agreement is closer to the current position of the second vessel than the first point of agreement from the current position of the second vessel, and will determine the range in which the first vessel passes in front of the second vessel if the first point of agreement is farther away from the current position of the second vessel.

3. The ship surveillance system as described in claim 1 or 2, wherein, The passage determination unit will determine the range in front of the second vessel as the range that the first vessel passes in front of the second vessel if the first vessel passes in front of the second vessel if the first vessel passes in front of the second vessel if the first vessel passes in behind the second vessel if the first vessel passes in behind the second vessel if the first vessel passes in behind the second vessel if the first vessel passes in behind the second vessel if the first vessel passes in behind the second vessel if the first vessel passes in behind the second vessel if the first vessel passes in behind the second vessel if the second ....

4. The ship surveillance system as described in claim 1 or 2, wherein, The determination unit determines the specified range including the point of agreement as a risk area where there is a risk of collision between the first vessel and the second vessel.

5. The ship surveillance system as described in claim 1 or 2, wherein, The passage determination unit determines the range in front of the first vessel and the range behind the second vessel based on the solution of the simultaneous equation including the first calculation formula and the second calculation formula under the condition that the second time is greater than the first time or the second time is less than the first time.

6. The ship surveillance system as described in claim 1 or 2, wherein, Let the first time be t O Let the speed of the first ship be v. O When the position of the first ship in the xy plane is set to (x, y) and the initial position of the first ship is set to the origin of the xy plane, the first calculation formula is expressed as follows: First move.

7. The ship surveillance system as described in claim 1 or 2, wherein, Let the second time be t T Let the x-component of the second ship's velocity be v. Tx Let the y-component of the second ship's velocity be v. Ty When the position of the second ship on the xy plane is set to (x, y) and the initial position of the second ship is set to (x0, y0), the second calculation formula is expressed as follows: Second move.

8. The ship surveillance system as described in claim 1 or 2, wherein, It also includes a display unit that displays, on the predicted course of the second vessel, the range in front of the first vessel and the range behind the second vessel.

9. A ship surveillance system, wherein, have: The first data generation unit generates first ship data representing the position and speed of the first ship. The second data generation unit generates second ship data representing the position and speed of the second ship. The first estimation unit creates a first calculation formula based on the first ship data. The first calculation formula represents the predicted position of the first ship in each direction after a first time, assuming that the first ship changes course and sails in any direction from its current position. The second estimation unit creates a second calculation formula based on the second ship data, the second calculation formula representing the predicted position of the second ship after a second time period; as well as The determination unit, based on the solution of the simultaneous equation including the first calculation formula and the second calculation formula under the condition that the second time is greater than the first time or the second time is less than the first time, determines the range in the predicted course of the second vessel represented by the second calculation formula, the range in front of the first vessel and the range in behind the first vessel.

10. A method for ship surveillance, wherein, Based on the first calculation formula, and using the first ship data representing the position and speed of the first ship, the predicted positions of the first ship in each direction after a first time interval are estimated, assuming the first ship changes course and sails in any direction from its current position. Based on the second calculation formula, the predicted course of the second vessel and the predicted position of the second vessel after a second time interval are estimated according to the second vessel data representing the position and speed of the second vessel. The side of the predicted course of the second vessel that is closer to the current position of the second vessel than the predicted position of the first vessel when the first time and the second time are equal is determined to be the range in which the first vessel passes in front of or behind the second vessel. The side that is farther away from the current position of the second vessel than the predicted position is determined to be the range in which the first vessel passes in front of or behind the second vessel.

11. An information processing apparatus, wherein, have: The first estimation unit, based on the first calculation formula, estimates the predicted position of the first vessel in each direction after a first time, assuming that the first vessel changes course in any direction and sails at its current position, according to the first vessel data representing the position and speed of the first vessel. The second estimation unit, based on the second calculation formula, estimates the predicted course of the second vessel and the predicted position of the second vessel after a second time, including the predicted course, based on the second vessel data representing the position and speed of the second vessel. as well as The determination unit determines the range in which the first ship passes in front of or behind the second ship if the predicted position of the first ship is closer to the current position of the second ship than the predicted position of the second ship when the first time and the second time are equal. The determination unit determines the range in which the first ship passes in front of or behind the second ship if the predicted position of the second ship is closer to the current position of the second ship than the predicted position of the first ship.

12. A computer program product comprising a computer program, wherein, This computer program causes the computer to perform: Based on the first calculation formula, and according to the first ship data representing the position and speed of the first ship, the predicted positions of the first ship in each direction after the first time are estimated, assuming that the first ship changes course and sails in any direction from its current position. Based on the second calculation formula, the predicted course of the second vessel and the predicted position of the second vessel after a second time are estimated based on the second vessel data representing the position and speed of the second vessel. as well as The side of the predicted course of the second vessel that is closer to the current position of the second vessel than the predicted position of the first vessel when the first time and the second time are equal is determined to be the range in which the first vessel passes in front of or behind the second vessel. The side that is farther away from the current position of the second vessel than the predicted position is determined to be the range in which the first vessel passes in front of or behind the second vessel.

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