Ship steering assistance device and ship steering assistance method

Abstract

To provide a maneuvering support device capable of displaying a collision danger zone matching maneuvering sensation of a vessel operator with a light calculation load.SOLUTION: A maneuvering support device 1 includes a risk calculation unit 33 and a display data generation unit 41. The risk calculation unit 33 calculates a collision risk value for determining whether or not to display a collision danger zone which is a zone with high possibility of a collision occurring between an own vessel and another vessel in the future based on a separation distance between positions of the other vessel predicted for a plurality of times in the future and the positions of the own vessel predicted corresponding to them, taking into consideration a physical size of at least one of the own vessel or the other vessel. A display data generation unit 41 generates display data for displaying the collision danger zone in the predicted positions for the other vessel based on a determination using the collision risk value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ship steering assist device. [Background technology]

[0002] Conventionally, there has been known a ship-steering support device that can calculate a zone where a collision between one ship and another ship will occur in the future by using navigation information of the ship and other ships. Non-Patent Document 1 discloses a method for calculating the zone using this type of ship-steering support device.

[0003] Non-Patent Document 1 discloses a method for calculating the OZT (Obstacle Zone by Target), which is the space within one ship's activity space that is obstructed by the presence and movement of another ship. The OZT calculation method in Non-Patent Document 1 is as follows: That is, by taking into account the speed errors that occur in one ship and another ship, and defining an arrival time probability distribution that probabilistically indicates the time it takes for one ship and another ship to arrive at an arbitrary point, the probability of the simultaneous presence of one ship and another ship at an arbitrary point is calculated. Locations where this probability of simultaneous presence is higher than a predetermined probability value are considered to be OZTs where there is a possibility of collision. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Imazu, Junma, Fukuto, Junji, and Numano, Masayoshi: Obstruction Zones and Their Marking by Other Ships, Transactions of the Japan Institute of Navigation, Vol. 107, pp. 191-197, September 2002. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method in Non-Patent Document 1 calculates the OZT by regarding the own ship and other ships as points, and does not take into account the actual size of the own ship and other ships. As a result, even if the ship operator steers the ship so as to avoid the OZT on the display, there is a risk that the own ship and other ships may come too close or collide with each other because the own ship and other ships actually have physical sizes.

[0006] Furthermore, the method of obtaining OZT by calculating the probability of simultaneous presence of one ship and another, as in Non-Patent Document 1, requires an extremely large amount of calculation. Therefore, with the method in Non-Patent Document 1, it is difficult to increase the number of OZT calculation points from the perspective of calculation load, making it difficult to improve the spatial resolution of the OZT display.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a ship-steering assistance device that can generate display data that accurately indicates the risk of collision, and that reduces the calculation load for generating the display data.

[0008] The problem to be solved by the present invention is as described above. Next, the means for solving this problem and the effects thereof will be explained.

[0009] According to an aspect of the present invention, there is provided a ship maneuvering assistance device having the following configuration. That is, this ship maneuvering assistance device comprises an other ship data acquisition unit, an other ship future position prediction unit, an own ship data acquisition unit, an own ship future position prediction unit, a risk calculation unit, and a display data generation unit. The other ship data acquisition unit acquires information regarding the position and speed of other ships. The other ship future position prediction unit predicts the position of the other ship at multiple future times if the other ship continues to navigate on the same course and at the same speed, based on the position and speed of the other ship acquired by the other ship data acquisition unit. The own ship data acquisition unit acquires information regarding the position and speed of the own ship. The own ship future position prediction unit predicts the position of the own ship corresponding to the position of the other ship predicted by the other ship future position prediction unit, based on the position and speed of the own ship acquired by the own ship data acquisition unit, if the own ship continues to navigate on an arbitrarily determined course and at the same speed at that position. The risk calculation unit calculates a collision risk value based on the separation distance between the predicted position of the other ship at each of the times and the corresponding predicted position of the ship itself to determine whether to display a collision danger zone, which is a zone where a collision between the ship itself and the other ship is likely to occur in the future. The corresponding predicted position of the ship itself is the ship's position that is closest to the other ship's position at that time among multiple predicted positions of the ship itself at that time. The display data generation unit generates display data for displaying the collision danger zone at the predicted position of the other ship based on a determination using the collision risk value.

[0010] This makes it possible to generate display data that uses the separation distance between the own ship and other ships to display zones where a collision between the own ship and other ships will occur in the future. Therefore, it is possible to display zones that are highly relevant and match the actual maneuvering sense of the ship operator. Furthermore, rather than calculating the probability of simultaneous presence of the own ship and other ships, which takes into account the occurrence of speed errors, it is possible to calculate the collision risk value based on the separation distance between the own ship and other ships. Furthermore, the separation distance can be calculated using concentric circles centered on the own ship at the current time and the position of the other ships. Therefore, the calculation load can be reduced.

[0011] In the above-mentioned ship maneuvering assistance device, it is preferable that the separation distance is calculated as the distance between the position of the other ship predicted at each of the times and the corresponding predicted position of the ship itself.

[0012] This allows a rational assessment of the risk of collision.

[0013] In the ship maneuvering assistance device, it is preferable that the risk calculation unit calculates the collision risk value taking into account the physical size of at least one of the ship and the other ship.

[0014] This can further improve the appropriateness of the display of the zones.

[0015] The ship maneuvering assistance device preferably has the following configuration: That is, the risk calculation unit is capable of calculating, based on the separation distance, an alert risk value for determining whether to display an alert zone, which is a zone where another ship is likely to enter the alert zone in the future, taking into account the physical size of the ship and the size of the alert zone that can be set in front of and / or behind the ship. The display data generation unit is capable of generating display data for displaying the alert zone at the predicted position of the other ship in a manner that is distinguishable from the collision danger zone, based on a determination using the alert risk value.

[0016] This allows the navigation system to display, when a navigation operator or the like sets a warning area in front of and / or behind the navigation system's own ship as an area where it is undesirable for other ships to enter, warning zones where other ships are likely to enter the warning area in the future, along with collision danger zones. This provides better support to the navigation system operator. In addition, because the warning zones and collision danger zones are displayed separately, it is easy for the navigation system operator to understand.

[0017] In the ship maneuvering assist device, it is preferable that the display data generation unit generates display data for displaying the warning zone when the warning risk value is equal to or greater than a predetermined threshold value.

[0018] This allows a warning zone to be displayed for areas where there is a predetermined level or more of a possibility that other ships will invade the warning area in the future.

[0019] In the above-described ship-steering assist device, it is preferable that the collision danger zone and the warning zone displayed based on the display data are different from each other in at least color.

[0020] This allows the operator to easily distinguish and understand the warning zones and collision danger zones that are displayed in different colors.

[0021] In the ship maneuvering assist device, it is preferable that the size of the alert area varies depending on the ship speed.

[0022] This allows the display of a warning zone that flexibly matches the operator's sense of the vessel, which changes depending on the vessel's speed. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a block diagram showing the electrical configuration of the ship steering assist device according to the first embodiment. [Figure 2] FIG. 10 is a diagram showing an example of calculation of a separation distance. [Figure 3] FIG. 10 is a diagram showing an example of a risk function for converting a separation distance into a risk value. [Figure 4] 3 is a diagram showing an example of displaying collision danger zones and warning zones in the situation of FIG. 2; [Figure 5] 10A and 10B are diagrams showing the display of collision danger zones and warning zones according to this embodiment in comparison with the display of a conventional OZT. [Figure 6] FIG. 6 is a block diagram showing the electrical configuration of a ship maneuvering assist device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Next, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the electrical configuration of a ship maneuvering assist device 1.

[0025] First, a description will be given of a first embodiment. A ship maneuvering assist device 1 of the first embodiment shown in Fig. 1 is provided on a ship that moves on water.

[0026] A display device 5 is connected to the ship maneuvering assistance device 1. The display device 5 is configured as, for example, a liquid crystal display, and displays information to assist ship maneuvering. The ship maneuvering assistance device 1 generates display data for displaying collision danger zones and warning zones on the display device 5, and outputs the data to the display device 5.

[0027] A collision danger zone is a zone where there is a high possibility of a collision between one's ship and another ship in the future. A warning zone is a zone where there is a low possibility of a collision, but there is a high possibility that another ship will intrude into a private area set in relation to one's ship in the future. These zones are areas on the other ship's planned course where another ship will interfere with the one's ship's course change (OZT), and are calculated using a method different from that of Non-Patent Document 1 mentioned above. Details of the collision danger zone and warning zone will be described later.

[0028] The ship maneuvering assistance device 1 comprises an other ship data processing unit 11, an own ship data processing unit 21, a set length storage unit 26, a calculation processing unit 31, and a display data generation unit 41.

[0029] More specifically, the ship maneuvering assistance device 1 is configured as a known computer and includes a CPU, ROM, RAM, etc. The ROM stores a program for generating display data for the collision danger zones and warning zones. Cooperation between the hardware and software allows the ship maneuvering assistance device 1 to operate as an other ship data processing unit 11, own ship data processing unit 21, set length storage unit 26, calculation processing unit 31, display data generation unit 41, etc.

[0030] The other ship data processing unit 11 acquires data necessary for displaying collision danger zones and warning zones regarding other ships present around the ship. The other ship data processing unit 11 includes an other ship data acquisition unit 12 and an other ship future position prediction unit 13.

[0031] The other ship data acquisition unit 12 acquires the other ship position Pr0, which is the current position of the other ship 3, and the other ship speed vector Vt, which is the ship speed vector of the other ship 3, as shown in the relationship between the own ship 2 and the other ship 3 in Figure 2.

[0032] More specifically, the ship maneuvering assistance device 1 in Fig. 1 is connected to a radar device (not shown) that detects the surroundings of the ship 2 and generates a radar image. This radar device has a target tracking (TT) function, which is a technology for detecting and tracking the movement of a detected target (another ship 3). The TT function is well known, so to briefly explain it, the TT function calculates the position and velocity vector of a target (another ship 3) that exists around the ship, based on the progress of past radar images.

[0033] The radar device outputs the position and velocity of the representative point as the position and velocity of the other ship 3. The position of the representative point is, for example, the position of the centroid of the echo image of the other ship 3 that appears on the radar image.

[0034] The radar device acquires the position and speed of other ships 3 relative to the own ship 2, but the position and speed vector of other ships 3 input to the other ship data acquisition unit 12 are converted in advance to be ground-based based on the position and heading of the own ship 2 obtained by appropriate means (for example, a known GNSS positioning device and heading sensor). The other ship data acquisition unit 12 outputs the acquired other ship position Pr0 and other ship speed vector Vt to the other ship future position prediction unit 13 for each detected target.

[0035] The other ship future position prediction unit 13 predicts the future position of the other ship 3. The obtained predicted position of the other ship 3 serves as a positional reference for determining whether or not a collision danger zone and a warning zone should be displayed at that position. In the following description, this position may be referred to as a judgment point.

[0036] This is explained in detail below. As shown in Figure 2, the other ship future position prediction unit 13 determines multiple future times T1, T2, ... at appropriate time intervals ΔT, starting from a reference time T0 (specifically, the current time), which is the time when the position and speed of the other ship 3 are obtained. The other ship future position prediction unit 13 then predicts the other ship positions Pr1, Pr2, ... at the above-mentioned future times T1, T2, ... based on the position and ship speed of the other ship 3 at the reference time T0 (other ship position Pr0 and other ship speed vector Vt). The other ship positions Pr1, Pr2, ... determined by the prediction become the decision points D1, D2, ....

[0037] When calculating other ship positions Pr1, Pr2,... (decision points D1, D2,...), the other ship future position prediction unit 13 assumes that the other ship 3 moves from the other ship position Pr0 while keeping constant the magnitude and direction of the other ship speed vector Vt acquired at the reference time T0. In other words, the other ship 3 is assumed to continue sailing on the same course and at the same speed as at the reference time T0. Therefore, the other ship positions Pr1, Pr2,... can be easily calculated.

[0038] As shown in Figure 2, the other ship positions Pr1, Pr2, ... are determined to be spaced at appropriate intervals on the course C, which is a straight line extending the other ship's speed vector Vt from the other ship position Pr0. In the example of Figure 2, the other ship positions Pr1, Pr2, ... are spaced at equal intervals, but this is just one example and details will be described later. The other ship future position prediction unit 13 outputs data indicating the positions of the acquired other ship positions Pr1, Pr2, ... (decision points D1, D2, ...) to the calculation processing unit 31 and the display data generation unit 41.

[0039] The own ship data processing unit 21 acquires data necessary for displaying collision danger zones and warning zones regarding the own ship 2. The own ship data processing unit 21 includes an own ship data acquisition unit 22 and an own ship future position prediction unit 23.

[0040] The own ship data acquisition unit 22 receives data relating to the own ship position P0, which is the position of the own ship, and the own ship speed vector V.

[0041] The own ship position P0 is the current position of the own ship 2. A GNSS positioning device (not shown) is connected to the ship maneuvering assistance device 1, and the own ship data acquisition unit 22 can acquire the own ship position P0, which is the position of the own ship 2, based on the positioning results input from the GNSS positioning device.

[0042] The own ship speed vector V is the current speed of the own ship 2. The own ship data acquisition unit 22 can acquire the own ship speed vector V, which is the speed of the own ship 2, by calculating the change in position obtained from the GNSS positioning device.

[0043] The ship's position P0 and ship's speed vector V refer to the position and speed of a representative point of the ship 2, specifically, the location where the GNSS antenna (not shown) is attached. The ship's data acquisition unit 22 outputs the acquired ship's position P0 and ship's speed vector V to the ship's future position prediction unit 23.

[0044] The own ship future position prediction unit 23 predicts the future position of the own ship at multiple times T1, T2, ... described above in the other ship future position prediction unit 13. Each predicted own ship position P1, P2, ... corresponds to the other ship positions Pr1, Pr2, ... predicted by the other ship future position prediction unit 13 at each time T1, T2, ...

[0045] When calculating the ship's position P1, P2,..., the ship's future position prediction unit 23 assumes that the magnitude of the ship's speed vector V acquired at the reference time T0 is constant, but that the direction of the ship's speed vector V changes to an arbitrary direction at the reference time T0, and that the ship 2 continues to navigate from the ship's position P0 in a constant direction thereafter. In other words, the ship 2 arbitrarily determines a course at the ship's position P0, but is then considered to continue navigating on that course and at the same speed. Therefore, the estimated ship's positions P1, P2,... are all located on concentric circles centered on the ship's position P0 at the reference time T0.

[0046] In Figure 2, some of the many estimated positions of own ship's position P1, P2,... are indicated by small circles. The radius of the circle in which the predicted own ship's position P1, P2,... is arranged (hereinafter referred to as own ship's position candidate circle E1, E2,...) is equal to the product of the time from the reference time T0 to each time T1, T2,... and the magnitude of the own ship's speed vector V.

[0047] 1 calculates the ship's future position candidate circles E1, E2, ... at each time T1, T2, .... The ship's future position prediction unit 23 outputs data relating to the ship's position candidate circles E1, E2, ... to the calculation processing unit 31 as predicted ship's positions P1, P2, ....

[0048] The set length storage unit 26 stores the own ship length L and the private length PL.

[0049] As shown in Figure 3(a), the ship length L is the total length of the ship 2 in the fore-and-aft direction. The ship length L indicates the physical size of the ship 2 in the fore-and-aft direction. In this embodiment, if another ship 3 is present within the range of the ship length L, a collision between the ship 2 and the other ship 3 is considered to occur. The ship position P0 acquired by the ship data acquisition unit 22 and the ship positions P1, P2,... predicted by the ship future position prediction unit 23 refer to the mounting position of the GNSS antenna on the hull, and this position (the representative point mentioned above, hereinafter referred to as the ship reference position) is usually located midway along the ship length L. Therefore, the parameter for the ship length L is a combination of the length L1 from the ship reference position to the bow and the length L2 from the ship reference position to the stern. The two lengths L1 and L2 are set appropriately in advance in the ship maneuvering assistance device 1.

[0050] The private length PL refers to the fore-and-aft length of the private area (warning area) where the ship operator feels that the intrusion of the other ship 3 is psychologically undesirable, even though it is not included in the ship's length L described above and therefore no physical contact will occur between the ship operator's ship 2 and the other ship 3. The private area can be likened to the personal area in which, when considering the distance between people, one feels wary if another person comes any closer in front of or behind oneself. The private length PL is set by the ship operator at any length on at least either the front or rear of the ship's length L. For example, the ship operator can set the private length PL to a length of 0.5 nautical miles on the front side of the ship's length L.

[0051] The set length storage unit 26 shown in FIG. 1 outputs the stored own ship length L and private length PL to the calculation processing unit 31.

[0052] Next, we will explain the calculation processing unit 31. The calculation processing unit 31 uses data output from the other ship data processing unit 11 and the own ship data processing unit 21 to determine by calculation whether or not to display a collision danger zone or a warning zone at each of the aforementioned decision points D1, D2, ...

[0053] The calculation processing unit 31 includes a separation distance calculation unit 32, a risk calculation unit 33, and a zone display determination unit .

[0054] The separation distance calculation unit 32 calculates separation distances R1, R2,..., which are the distances between the other ship positions Pr1, Pr2,..., that are predicted to be reached at each future time T1, T2,..., and the corresponding own ship positions P1, P2,...,.

[0055] Since separation distances R1, R2, ... are used to evaluate the risk of collision, it is reasonable to consider the case in which the own ship 2 and the other ship 3 come closest to each other among the various predicted cases. Therefore, when calculating separation distance R1 at time T1, for example, separation distance calculation unit 32 selects the position closest to the other ship position Pr1 at time T1 from among the many own ship positions P1 predicted at that time T1.

[0056] In Figure 2, the own ship position P1 selected from the many predicted own ship positions P1 for calculating the separation distance R1 is indicated by a black circle. The separation distance R1 is calculated as the distance between the own ship position P1 indicated by a black circle and the other ship position Pr1.

[0057] Taking time T1 as an example, separation distance R1 means the minimum distance between a point on the own ship's position candidate circle E1 and the other ship's position Pr1. Separation distance R1 at time T1 can be easily calculated by finding the distance between the other ship's position Pr1 at that time T1 and the own ship's position P0 (the center of the own ship's position candidate circle E1) at reference time T0, and then subtracting the radius of the own ship's position candidate circle E1 from this distance. The same applies to separation distances R2,... at other times T2,...

[0058] In this way, the separation distance calculation unit 32 assumes that the ship speeds of the own ship 2 and the other ship 3 are constant and calculates the separation distance Rn, which is the distance between the predicted future position of the own ship 2 and the future position of the other ship 3. Therefore, the separation distance Rn can be obtained by a simple geometric calculation.

[0059] Since the separation distance Rn is calculated using the above method, the value can be positive or negative. If the separation distance Rn is positive, it means that the ship's position Pn is closer to the ship's position P0 at the reference time T0 than the other ship's position Prn. If the separation distance Rn is negative, it means that the ship's position Pn is farther from the ship's position P0 at the reference time T0 than the other ship's position Prn. In the example of Figure 2, separation distances R1, R2, R3, and R4 are positive, and separation distance R5 is negative.

[0060] When the separation distance Rn is positive, it indicates that when the first ship 2 and the second ship 3 are closest to each other, the second ship 3 is located to the bow of the first ship 2. When the separation distance Rn is negative, it indicates that when the first ship 2 and the second ship 3 are closest to each other, the second ship 3 is located to the stern of the first ship 2.

[0061] In this embodiment, when the distance calculation unit 32 calculates the separation distance Rn, both the own ship 2 and the other ship 3 are treated as points, and their physical sizes are not considered. The separation distance Rn is expressed as the distance between the own ship reference position, which is the representative point of the own ship 2, and the representative point of the other ship 3.

[0062] The risk calculation unit 33 in FIG. 1 calculates a risk value (collision risk value, warning risk value) RPn, which is a parameter for determining whether to display the collision risk zone and the warning zone. Specifically, the risk calculation unit 33 uses a predetermined risk function FR to convert each separation distance Rn calculated by the separation distance calculation unit 32 into a risk value RPn. The risk value RPn is a value between 0 and 1. A value of 0 indicates that there is no possibility of collision between the own ship 2 and the other ship 3, and a value of 1 indicates that the own ship 2 and the other ship 3 will collide.

[0063] The risk function FR used by the risk calculation unit 33 for the calculation is determined by referring to the stored content of the set length storage unit 26. FIG. 3(b) shows the risk function FR used in this embodiment as a graph with the own ship reference position in FIG. 3(a) as the origin, the separation distance R on the horizontal axis, and the risk value RP on the vertical axis.

[0064] As shown in FIG. 3(b), when the separation distance R is in the range corresponding to the own ship length L (-L2 ≤ R ≤ L1), the value of the risk function FR is 1. Also, when the separation distance R is in the range corresponding to the private length PL (L1 < R < L1 + PL), the value of the risk function FR is greater than 0 and less than 1, and this value monotonically decreases as the separation distance R increases. When the separation distance R is not in the range corresponding to either the own ship length L or the private length PL (R < -L2 or R ≥ L1 + PL), the value of the risk function FR is 0.

[0065] Thus, in this embodiment, the risk calculation unit 33 calculates the risk value RP using the risk function FR whose value becomes 1 in the range where the separation distance R corresponds to the own ship length L. Therefore, it is possible to evaluate the possibility of collision in consideration of the physical length of the own ship.

[0066] The risk calculation unit 33 outputs the risk values ​​RP1, RP2, . . . obtained by substituting the separation distances R1, R2, .

[0067] The zone display determination unit 34 determines whether to display a collision danger zone, a warning zone, or neither at each determination point D1, D2, ..., according to the risk values ​​RP1, RP2, ... output from the risk calculation unit 33.

[0068] Specifically, the zone display determination unit 34 determines that it is necessary to display a collision danger zone when the risk value RPn output from the risk calculation unit 33 is 1. The zone display determination unit 34 determines that it is necessary to display a warning zone when the risk value RP output from the risk calculation unit 33 is smaller than 1 but larger than 0. The zone display determination unit 34 determines that it is unnecessary to display either the collision danger zone or the warning zone when the risk value RP is 0.

[0069] As described above, the calculation processing unit 31 of this embodiment does not calculate the probability distribution by taking speed error into account, as is done in conventional OZTs. In other words, the calculation processing unit 31 assumes that there is no error in the own ship's speed vector V and the other ship's speed vector Vt, and simply determines whether or not to display a collision danger zone and a warning zone based on whether the positional relationship between the reference position of the own ship 2 indicated by the separation distance Rn and the representative point of the other ship 3 is within the range of the own ship's length L or the range of the private length PL. This significantly reduces the amount of calculation required for the determination.

[0070] Next, we will explain the display data generation unit 41. Fig. 4 is a diagram showing a display example of the collision danger zone 91 and the warning zone 92 in the situation of Fig. 2. Fig. 5 is a diagram showing the display of the collision danger zone 91 and the warning zone 92 according to this embodiment in comparison with the display of a conventional OZT.

[0071] The display data generating unit 41 generates display data for displaying information for assisting the vessel operator on the display device 5, and outputs the data to the display device 5 via an appropriate interface.

[0072] Fig. 4 shows an example of a display screen on the display device 5. As shown in Fig. 4, the display data generation unit 41 generates display data that graphically shows the position and speed of the ship 2 and the position and speed of the other ship 3. The display data generation unit 41 further displays a collision danger zone 91 or a warning zone 92 at each of the judgment points D1, D2, ... according to the judgment result of the zone display judgment unit 34.

[0073] Figure 4 shows an example of the display on the display device 5 in the situation of Figure 2, where the risk value RP4 corresponding to the separation distance R4 is 1, the risk value corresponding to the separation distance R3 is 0.3, and the risk values ​​corresponding to the other separation distances R1, R2, and R5 are all 0.

[0074] As shown in Fig. 4, a graphic representing a collision danger zone 91 is displayed at decision point D4, and a graphic representing a warning zone 92 is displayed at decision point D3. No graphic is displayed at the other decision points D1, D2, and D5. Note that decision points D1, D2, ... are points used as reference points for calculation, so although they are drawn in Fig. 4 for the sake of explanation, they are not actually displayed on the screen.

[0075] The collision danger zone 91 and the warning zone 92 are displayed as circular figures with the judgment point Dn at their centers. The size of the circle is determined appropriately so as not to be too small. For example, the size of the circle can be determined so that its diameter is equal to the ship's length L.

[0076] For example, when a circular graphic of the collision danger zone 91 is displayed at each of two adjacent decision points Dn, it is undesirable for a gap to appear between the circles. For this reason, the time interval ΔT when the other ship future position prediction unit 13 determines the decision point Dn is determined so that the distance between adjacent decision points Dn is sufficiently short, taking into account the size of the circle and the magnitude of the other ship's ship speed vector Vt. This ensures regional continuity in the display of the collision danger zone 91 or the warning zone 92.

[0077] The own ship's position P0, own ship's speed vector V, other ship's position Pr0, and other ship's speed vector Vt input to the ship maneuvering assistance device 1 all change from moment to moment, and the display of the collision danger zone 91 and warning zone 92 needs to be updated in real time accordingly. In addition, there may be more than one other ship 3 around the own ship 2, and in this case, processing to display the collision danger zone 91 and warning zone 92 must be performed for each other ship 3. Therefore, it is important to reduce the calculation load required for processing.

[0078] Theoretically, the other ship future position prediction unit 13 can generate an infinite number of judgment points Dn, but as the number of judgment points Dn increases, the calculation load becomes heavy. Therefore, in this embodiment, a predetermined judgment limit distance is set, and the position of the judgment point Dn output by the other ship future position prediction unit 13 is limited to within the judgment limit distance from the other ship position Pr0. This makes it possible to prevent the calculation load from becoming excessive.

[0079] However, in this embodiment, the amount of calculation required to determine whether or not to display the collision danger zone 91 and the warning zone 92 at each judgment point Dn is reduced compared to the conventional method, as described above. Therefore, even if a large number of judgment points Dn are generated by shortening the distance between adjacent judgment points Dn or lengthening the judgment limit distance, processing can be performed in real time without any problems. This makes it possible to increase the resolution at which the collision danger zones 91 and the warning zones 92 are displayed, or to display the collision danger zones 91 and the warning zones 92 based on predictions made further into the future.

[0080] The display data generated by the display data generation unit 41 can be configured to display different colors on the display device 5 for the collision danger zone 91 and the warning zone 92. In Fig. 4, for convenience of illustration, the different display colors for the collision danger zone 91 and the warning zone 92 are shown by solid and dashed lines. This allows the ship operator to clearly distinguish and grasp the area where a collision with another ship 3 is likely to occur and the area where a collision will not occur but where the other ship 3 is likely to enter the private length PL described above, thereby making it easier to understand the situation.

[0081] The manner in which the collision danger zone 91 and the warning zone 92 are displayed differently on the display device is not limited to changing colors. For example, the collision danger zone 91 and the warning zone 92 may be displayed with or without a fill, or with different transparency or patterns for the filled-in areas. As shown in FIG. 4, the contour lines of the zone shapes may be different, such as solid lines and dashed lines. Furthermore, the zone shapes may be configured to allow the vessel operator to distinguish between the collision danger zone 91 and the warning zone 92 by adding letters, symbols, small marks, or the like to the zone shapes.

[0082] The warning zone 92 corresponds to a risk value RP greater than 0 and less than 1, but the display data generation unit 41 may generate display data for the warning zone 92 that changes the display mode depending on the magnitude of the risk value RP. For example, it is possible to gradually increase the transparency of the outline or fill in the interior of the displayed warning zone 92 as the risk value RP decreases. Alternatively, the collision danger zone 91 may be displayed in red, and the warning zone 92 may be displayed in a color that gradually changes from red to yellow as the risk value RP decreases.

[0083] The warning zone may be displayed only when the risk value RP is greater than a predetermined threshold set by the vessel operator, instead of being displayed uniformly when the risk value RP is greater than 0 and less than 1. This allows for display according to the vessel operator's preferences.

[0084] The collision danger zone 91 and the warning zone 92 can also be displayed in exactly the same manner.

[0085] As described above, in this embodiment, the risk function FR evaluates the risk of collision taking into account the ship's length L. That is, the ship 2 is not treated as a point, but as a long, thin line extending in the fore-and-aft direction by the ship's length L. Therefore, even in the case of a large ship with a considerably long ship length L, for example, it is possible to display areas with a high risk of collision in an appropriate position taking into account the actual size of the ship.

[0086] Figure 5 shows a comparison of the display of the collision danger zone 91 of this embodiment and the conventional OZT under the same circumstances. As shown in Figure 5(a), the collision danger zone 91 of this embodiment takes into account the own ship's length L, and thereby expands the zone area closer to the other ship 3 than the conventional OZT shown in Figure 5(b) (expanded portion 91e). This display indicates that, taking into account the actual own ship's length L, in order to avoid a collision with the other ship 3, the own ship 2 should not be maneuvered into not only the area that overlaps with the conventional OZT, but also into the expanded portion 91e that extends from it.

[0087] In the display example of this embodiment shown in Figure 5(a), a warning zone 92 resulting from setting the private length PL forward of the own ship 2 is displayed closer to the other ship 3 than the collision danger zone 91. This display indicates that if the ship is steered into the warning zone 92, there is a high possibility that the other ship 3 will enter the area corresponding to the private length PL forward of the own ship 2.

[0088] In the display example of this embodiment shown in Figure 5(a), the collision danger zone 91 is not displayed at location N1, which corresponds to the circle at the left end of the conventional OZT shown in Figure 5(b). This is because, in this embodiment, the length L2 of the portion of own ship's length L that is aft of the own ship's reference position is significantly shorter, and this is appropriately taken into consideration by the risk calculation unit 33. The example of Figure 5(a) shows a case where a private length PL is not set aft of own ship 2, but if the aft private length PL is set appropriately, the warning zone 92 will be displayed at the above-mentioned location N1.

[0089] In the above explanation, the collision risk is evaluated assuming that the position of the radar antenna equipped in the radar device is the same as the position of the GNSS antenna of the GNSS positioning device (in other words, the ship's own reference position). However, if the distance between the radar antenna mounting position and the GNSS antenna mounting position cannot be ignored, it is preferable to recalculate the ship's position acquired by the other ship data acquisition unit 12 so that the GNSS antenna position is used as the reference, as this enables more accurate collision calculations. On the other hand, the ship's own reference position may be set to coincide with the radar antenna position rather than the GNSS antenna position. In this case, the ship's own position, etc. acquired by the other ship data processing unit 11 will be recalculated so that the radar antenna position is used as the reference.

[0090] As described above, the ship maneuvering assistance device 1 of this embodiment comprises an other ship data acquisition unit 12, another ship's future position prediction unit 13, own ship data acquisition unit 22, own ship's future position prediction unit 23, risk calculation unit 33, and display data generation unit 41. The other ship data acquisition unit 12 acquires information relating to the position and speed of the other ship 3 (other ship's position Pr0 and other ship's speed vector Vt). The other ship's future position prediction unit 13 predicts other ship's positions Pr1, Pr2, ... at multiple future times T1, T2, ... based on the other ship's position Pr0 and other ship's speed vector Vt acquired by the other ship data acquisition unit 12, if the other ship 3 continues to navigate on the same course and at the same speed. The own ship data acquisition unit 22 acquires information relating to the position and speed of the own ship 2 (own ship's position P0 and own ship's speed vector V). The own ship future position prediction unit 23 predicts the own ship's position P1, P2,... corresponding to the other ship positions Pr1, Pr2,... predicted by the other ship future position prediction unit 13 if the own ship 2 continues to navigate on an arbitrarily determined course and at the same speed at the own ship's position P0, based on the own ship position P0 and own ship speed vector V acquired by the own ship data acquisition unit 22. The risk calculation unit 33 calculates a risk value RP for determining whether to display a collision danger zone 91, which is a zone where there is a high possibility of a future collision between the own ship 2 and another ship 3, based on the separation distances R1, R2,... between the other ship positions Pr1, Pr2,... predicted at each time T1, T2,... and the corresponding predicted own ship positions P1, P2,.... The display data generation unit 41 generates display data for displaying the collision danger zone 91 at the predicted other ship positions Pr1, Pr2,... based on the determination using the risk value RP.

[0091] As a result, the size of the own ship 2 and the separation distances R1, R2, ... between the own ship 2 and the other ship 3 can be used to display on the display device 5 a collision danger zone 91, which is a zone where a collision between the own ship 2 and the other ship 3 may occur in the future. In other words, because the size of the own ship 2 is taken into consideration, it is possible to display a collision danger zone 91 that is more appropriate and matches the actual steering feel of the navigator. Furthermore, rather than calculating the probability of the own ship and the other ship being simultaneously present by taking into account the occurrence of speed errors as in the past, the display decision for the collision danger zone 91 is made based on the separation distances R1, R2, ... between the own ship 2 and the other ship 3, which significantly reduces the calculation load.

[0092] Next, a second embodiment will be described. Fig. 6 is a block diagram showing the electrical configuration of a ship maneuvering assistance device 1x of the second embodiment. In the description of the second embodiment, the same or similar members as those in the first embodiment described above are denoted by the same reference numerals in the drawings, and their description may be omitted.

[0093] 6, the other ship data acquisition unit 12 acquires information on the position and speed of other ships 3 from an AIS device rather than a radar device. The AIS device is an automatic identification system for ships that exchanges navigation information between multiple ships, and can acquire data such as the position, ground speed, name, length and width of the other ship 3, and the position of the positioning antenna.

[0094] The other ship data acquisition unit 12 acquires information not only on the position and speed of the other ship 3, but also on the length of the other ship 3 and the fore-aft position of the positioning antenna. Based on the information on the length of the other ship 3 and the position of the positioning antenna, the other ship data acquisition unit 12 outputs to the risk calculation unit 33 the length from the position of the positioning antenna of the other ship 3 to the bow and the length from the positioning antenna to the stern.

[0095] The risk calculation unit 33 calculates the risk value RP using the own ship's length L and private length PL obtained from the set length memory unit 26, and the lengths of other ships obtained from the other ship data acquisition unit 12. The risk function FR used in this embodiment can be obtained by modifying the graph in Figure 3(b) so that the region of the separation distance R where the risk value RP is 1 is appropriately expanded in the fore-and-aft direction of the own ship 2, taking into account the length of the other ship 3.

[0096] In this embodiment, the possibility of collision is evaluated by treating not only the own ship 2 but also the other ship 3 not as points but as elongated lines extending in the fore-and-aft direction by the same length. Therefore, the display of the collision danger zone 91 and the warning zone 92 can be made more consistent with the actual steering feel of the ship operator.

[0097] The information about the other ship 3 obtained by the AIS may not include information about the size of the other ship 3. In this case, the risk calculation unit 33 can calculate the risk value RP by uniformly assuming that the length of the other ship 3 is equal to the length appropriately set in advance by the ship operator.

[0098] The preferred embodiment of the present invention has been described above, but the above configuration can be modified, for example, as follows.

[0099] The other ship positions Pr1, Pr2,... (decision points D1, D2,...) determined by the other ship future position prediction unit 13 on the course C of the other ship position Pr0 do not have to be arranged at equal intervals as shown in Figure 2, but can also be arranged at unequal intervals. For example, multiple virtual lines radiating out from the position of the own ship 2 at equal angular intervals can be considered, and the other ship positions Pr1, Pr2,... can be determined at the positions where each virtual line intersects with the course C. In this case, multiple virtual lines can be arranged so that the angular interval between virtual lines close to the current course of the own ship 2 (for example, virtual lines within 10° left or right of the course of the own ship 2) is smaller than the angular interval between virtual lines that are not. In this case, since the decision points D1, D2,... can be densely determined in areas that are likely to interfere with the current course of the own ship 2, the spatial resolution for displaying collision danger zones and warning zones near the planned course of the own ship 2 can be improved.

[0100] As described above, the other ship positions Pr1, Pr2,... correspond to multiple future times T1, T2,... Therefore, depending on how the other ship positions Pr1, Pr2,... are determined, the size of the corresponding own ship position candidate circles E1, E2,... will also change.

[0101] The own ship reference position is not limited to the position described in the above embodiment, but can be set to any point on the own ship 2. For example, the own ship reference position can be set to the position that serves as the axis when the own ship 2 is turning (the position of the pivot point in the hull movement).

[0102] In actual ship operation, when sailing at high speed, attention should be paid to other ships 3 further ahead than when sailing at low speed. Taking this into consideration, the private length PL, which is set particularly at the front of the own ship 2, may be configured to change automatically depending on the magnitude of the own ship's ship speed vector V.

[0103] In the second embodiment, the other ship data processing unit 11 can also be configured to obtain the length of the other ship 3 obtained from the shape of the echo image tracked by the TT function in the radar device described in the first embodiment, rather than using an AIS.

[0104] The display of the collision danger zone 91 can be determined by taking into account not only the length but also the width of the own ship 2. The display of the warning zone 92 can be determined by taking into account not only the length but also the width of the private area. Similarly, the display of the other ship 3 can be determined by taking into account not only the length but also the width.

[0105] The risk value (collision risk value) for determining whether to display the collision danger zone 91 and the risk value (warning risk value) for determining whether to display the warning zone 92 may be calculated using separate functions rather than a common risk function FR.

[0106] The collision danger zone 91 and the warning zone 92 can be displayed in any manner. For example, instead of a circle centered on the determination point Dn, they may be displayed as lines connecting the determination points Dn. The thickness of the lines can be set appropriately.

[0107] In the risk function FR, the risk value RP in the private length PL may decrease, for example, in a curved manner instead of decreasing linearly as shown in FIG. 3(b).

[0108] In the first embodiment, the risk calculation unit 33 of the calculation processing unit 31 calculates the risk value RP taking into account the physical size of the ship 2. Alternatively, the physical size of the ship 2 may be taken into account when the separation distance calculation unit 32 calculates the separation distance Rn. For example, the separation distance calculation unit 32 may take into account the length L1 from the ship's reference position to the bow and calculate the minimum distance between the predicted position of the representative point of the other ship 3 and the predicted future position of the tip of the ship's bow as the separation distance Rn.

[0109] The ship maneuvering assist device 1 may be integrally provided with the display device 5. [Explanation of symbols]

[0110] 1. Navigation support device 11 Other ship data processing section 32 Separation distance calculation section 33 Risk Calculation Department 41 Display data generation unit

Claims

1. an other ship data acquisition unit that acquires information about the position and speed of other ships; a future ship position prediction unit that predicts the position of the other ship at multiple future times if the other ship continues to sail on the same course and at the same speed, based on the position and speed of the other ship acquired by the other ship data acquisition unit; an own ship data acquisition unit that acquires information about the position and speed of the own ship; a ship's future position prediction unit that predicts the ship's position corresponding to the other ship's position predicted by the other ship's future position prediction unit, based on the ship's position and speed acquired by the ship's data acquisition unit, if the ship continues to navigate at the same speed and on a course arbitrarily determined at that position; a risk calculation unit that calculates a collision risk value to determine whether to display a collision danger zone, which is a zone where a collision between the ship and the other ship is likely to occur in the future, based on the distance between the position of the other ship predicted at each of the times and the position of the ship that is closest to the position of the other ship at that time among multiple predicted positions of the ship at that time; and a display data generation unit that generates display data for displaying the collision danger zone at the predicted position of the other ship based on a judgment using the collision risk value; and Equipped with The separation distance is calculated as the distance between the position of the other ship predicted at each of the times and the position of a concentric circle whose center is the position of the ship at the current time and whose radius corresponds to each of the times and contains multiple predicted positions of the ship. A ship steering assistance device characterized by:

2. The ship steering assist device according to claim 1, A ship maneuvering assistance device characterized in that the risk calculation unit calculates the collision risk value taking into account the physical size of at least one of the ship itself and the other ship.

3. The ship steering assist device according to claim 1 or 2, the risk calculation unit is capable of calculating an alert risk value based on the separation distance, taking into account the physical size of the ship and the size of the alert area that can be set in front of and / or behind the ship, for determining whether to display an alert zone, which is a zone where other ships are likely to invade the alert area in the future; The display data generation unit is capable of generating display data for displaying the warning zone at the predicted position of the other ship in a manner that makes it distinguishable from the collision danger zone based on a judgment using the warning risk value.

4. The ship steering assist device according to claim 3, The display data generating unit generates display data for displaying the warning zone when the warning risk value is equal to or greater than a predetermined threshold.

5. The ship steering assist device according to claim 3 or 4, The collision danger zone and the warning zone displayed based on the display data are at least different in color from each other.

6. The ship maneuvering assist device according to any one of claims 3 to 5, A ship maneuvering support device characterized in that the size of the warning area changes depending on the ship's speed.

7. Obtain information about the position and speed of other ships, Based on the acquired position and speed of the other vessel, the system predicts the position of the other vessel at multiple future times if the other vessel continues to sail on the same course and at the same speed; Obtain information about your ship's position and speed, Based on the acquired position and speed of the own ship, predict the position of the own ship that corresponds to the predicted position of the other ship if the own ship continues to navigate on a course arbitrarily determined at that position and at the same speed; calculate a collision risk value for determining whether to display a collision danger zone, which is a zone where a collision between the ship and the other ship is likely to occur in the future, based on the distance between the predicted position of the other ship at each of the times and the position of the ship that is closest to the position of the other ship at that time among multiple predicted positions of the ship at that time; generating display data for displaying the collision danger zone at the predicted position of the other ship based on a judgment using the collision risk value; In the ship maneuvering assistance method, The separation distance is calculated as the distance between the position of the other ship predicted at each of the times and the position of a concentric circle whose center is the position of the ship at the current time and whose radius corresponds to each of the times and contains multiple predicted positions of the ship. Ship steering assistance methods.

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