Sailing route plan system and sailing route plan method

Abstract

To provide a sailing route plan device and method for safely navigating a mobile body such as a ship by avoiding a collision with an obstacle such as a plurality of ships.SOLUTION: A sailing route plan system plans a sailing route to a destination of a mobile body to move on the water. The sailing route plan system comprises: a plan sailing route information acquisition section for acquiring plan sailing route information which indicates a plan sailing route of the mobile body; a mobile body information acquisition section for acquiring mobile body information including a position, movement direction, and speed of the mobile body; an obstacle information acquisition section for acquiring obstacle information including positions, movement directions, and speeds of one or a plurality of obstacles existing in the periphery of the mobile body; a collision risk value calculation section for calculating a collision risk value which indicates the risk of a collision of the mobile body with the obstacle based on the mobile body information and the obstacle information; and a collision avoidance route setting section for setting a collision avoidance route which is the route deviated from the plan sailing route and whose collision avoidance ending point direction is the pre-set ending point direction, when it is determined that the collision avoidance is required after determining whether the mobile body has to avoid the collision based on the collision risk value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates primarily to a marine navigation system for safely navigating a ship, and more specifically to a route planning system and a route planning method for safely navigating a ship while avoiding collisions with surrounding obstacles. [Background technology]

[0002] Generally, before starting a voyage, a mobile body such as a ship sets a planned route from a departure point or port location to a destination (destination port). In recent years, mobile bodies have been equipped with navigation systems and devices that monitor the mobile body moving on the planned route in order to safely navigate the set planned route. Conventional navigation systems, etc., use multiple sensor units to acquire mobile body information and obstacle information in order to track and identify the positions of obstacles and other ships, such as mobile bodies, near the ship on the planned route in order to avoid obstacles such as other ships.

[0003] However, while sailing on the planned route, situations may arise where the planned route must be changed due to human factors such as the above-mentioned obstacles or the appearance of another ship crossing the planned route.In addition, natural factors such as sudden changes in sea conditions, tides, and other disturbances may force a change in navigation route from the planned route.

[0004] For this reason, ship navigation personnel need assistance in avoiding collisions with obstacles and other ships, and in safely navigating a moving object such as a ship along a planned route. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US2020 / 0310434 Summary of the Invention [Problem to be solved by the invention]

[0006] The route planning system and route planning method of the present invention aim to provide a system and method that assists personnel navigating a mobile vessel in safely navigating the mobile vessel by avoiding collisions with obstacles and other vessels. [Means for solving the problem]

[0007] The route planning system and route planning method of the present invention have been made to solve the above-mentioned problems, and in order to plan a route to a destination for a moving body moving on water, the system includes a planned route information acquisition unit that acquires planned route information indicating the planned route of the moving body (own ship), a moving body information acquisition unit that acquires moving body information including the position, movement direction, and speed of the moving body, and an obstacle information acquisition unit that acquires obstacle information including the position, movement direction, and speed of one or more obstacles around the moving body.Furthermore, the system includes a collision risk value calculation unit that calculates a collision risk value indicating the risk of collision between the moving body and the obstacle based on the moving body information and the obstacle information, and an avoidance route setting unit that determines whether the moving body needs to avoid collision based on the collision risk value, and if it determines that avoidance is necessary, sets an avoidance route that deviates from the planned route and whose avoidance endpoint bearing is a predetermined endpoint bearing.

[0008] In the above-described route planning system of the present invention, the end point heading may be the heading that coincides with the moving direction of the moving body at the avoidance start position where the moving body starts to avoid collision from the planned route, or the end point heading may be the heading that coincides with the direction of the moving body at a selected position on the planned route where the moving body has not yet been sailed. In this case, the end point heading may be the direction on the planned route at the position on the planned route where the not yet sailed position is closest to the end point position. Alternatively, the end point heading may be the direction of the planned route at the position on the not yet sailed planned route on the circumference of a concentric circle centered on the avoidance start point, which is equal to the straight-line distance between the avoidance start point and the end point.

[0009] In addition, the end point direction can be a direction that corresponds to the direction from the avoidance start position where the mobile body starts to avoid the planned route toward the destination, or the end point direction can be a direction that corresponds to the direction toward a selected position on the planned route among the unnavigated routes of the mobile body. In other words, the avoidance route can be a route that deviates from the planned route, and even if the end point position is not on the planned route, the direction at the end point position can be a direction that is set in advance.

[0010] In the route planning system of the present invention, the avoidance route setting unit may include an avoidance route pattern generation unit that generates one or more potential avoidance route patterns between the avoidance start position and the avoidance end point, and an avoidance route selection unit that selects an avoidance route from one or more potential avoidance route patterns based on the collision risk value for each of the one or more potential avoidance route patterns calculated by the collision risk value calculation unit.The potential avoidance route pattern with the smallest collision risk value may be selected as the avoidance route from the above potential avoidance route patterns.

[0011] The route planning system of the present invention may further include an avoidance route distance calculation unit that calculates the avoidance distance between the avoidance start point and the avoidance end point when the mobile body navigates along one or more potential avoidance route patterns, and the avoidance route selection unit may select an avoidance route from one or more potential avoidance route patterns based on the collision risk value and the avoidance distance of the one or more potential avoidance route patterns.

[0012] The route planning system of the present invention may also be configured so that the avoidance route setting unit extracts a maximum collision risk obstacle corresponding to a maximum collision risk value from obstacles that would hinder the mobile body when navigating one or more potential avoidance route patterns, selects a potential avoidance route pattern in which the maximum collision risk value of the maximum collision risk obstacle is equal to or less than a predetermined collision risk threshold, and selects an avoidance route from the selected multiple potential avoidance route patterns based on the collision risk value and avoidance distance.

[0013] Furthermore, the route planning system of the present invention may include a congestion risk value calculation unit that calculates a congestion risk value indicating the degree of simultaneous approach to multiple obstacles based on a collision risk value between the moving body and each of the multiple obstacles, and the avoidance route setting unit may determine whether the moving body needs to avoid collision based on the congestion risk value in addition to the collision risk value, and may set the avoidance route if the avoidance necessity determination unit determines that avoidance is necessary. Here, the congestion risk value calculation unit may calculate the congestion risk value based on the logical sum of the collision risk values corresponding to each of the multiple obstacles.

[0014] In the route planning system of the present invention, the congestion risk value calculation unit may exclude the maximum collision risk value of the maximum collision risk obstacle corresponding to the maximum collision risk value from obstacles that would be an obstacle when the mobile body navigates one or more potential avoidance route patterns, and calculate the congestion risk value based on multiple collision risk values including the second largest collision risk value among the multiple collision risk values, because the risk of the obstacle with the maximum obstacle risk value can be evaluated based on the collision risk value.

[0015] Here, the avoidance route setting unit may include an avoidance route pattern generation unit that generates one or more potential avoidance route patterns between the avoidance start position and the avoidance end point, and an avoidance route selection unit that selects an avoidance route from the one or more potential avoidance route patterns based on the collision risk value and the congestion risk value of the one or more potential avoidance route patterns calculated by the collision risk value calculation unit.

[0016] Furthermore, the collision avoidance route setting unit may extract, from among obstacles that will hinder the mobile body when it navigates through one or more potential collision avoidance route patterns, a maximum collision risk obstacle corresponding to the maximum collision risk value, and select a potential collision avoidance route pattern in which the maximum collision risk value of the maximum collision risk obstacle is equal to or less than a predetermined collision risk threshold.Then, from the selected one or more potential collision avoidance route patterns, it may select one or more potential collision avoidance route patterns in which the collision risk value is equal to or less than the predetermined threshold, and select a potential collision avoidance route pattern from the selected one or more potential collision avoidance route patterns based on the collision risk value and congestion risk value.

[0017] In the above configuration, the route planning system of the present invention may further include an avoidance route distance calculation unit that calculates the avoidance distance between the avoidance start point and the avoidance end point when the mobile body navigates along one or more potential avoidance route patterns, and the avoidance route selection unit may select the avoidance route from the one or more potential avoidance route patterns based on the collision risk value, congestion risk value and avoidance distance of the one or more potential avoidance route patterns.

[0018] Here, if there is no avoidance route in which the collision risk value is equal to or less than the collision risk threshold and the congestion risk value is equal to or less than a predetermined congestion risk threshold, the avoidance route setting unit may change the restriction on the end direction and set a new avoidance route in which the collision risk value is equal to or less than the collision risk threshold and the congestion risk value is equal to or less than the congestion risk threshold.

[0019] The avoidance route setting unit may also select one or more potential avoidance route patterns for which the collision risk value is equal to or less than the collision risk threshold and the congestion risk value is equal to or less than the congestion risk threshold, and select the potential avoidance route pattern with the shortest avoidance distance as the avoidance route.

[0020] The route planning system of the present invention may be configured such that the mobile body information acquisition unit acquires mobile body information including the position, movement direction, and speed of the mobile body at a predetermined period, the obstacle information acquisition unit acquires obstacle information including the position, movement direction, and speed of one or more obstacles around the mobile body at a predetermined period, the collision risk value calculation unit calculates a collision risk value indicating the risk of collision between the mobile body and the obstacle based on the mobile body information and the obstacle information at a predetermined period, and the avoidance route setting unit determines whether the mobile body needs to take avoidance based on the collision risk value at a predetermined period, and if it determines that avoidance is necessary, sets an avoidance route.

[0021] The route planning method of the present invention is a route planning method for planning a route to a destination of a moving body moving on water, and includes the steps of: acquiring planned route information indicating the planned route of the moving body; acquiring moving body information including the position, moving direction, and speed of the moving body; and acquiring obstacle information including the position, moving direction, and speed of one or more obstacles around the moving body. Then, based on the moving body information and obstacle information, a collision risk value indicating the risk of collision between the moving body and the obstacle is calculated, and based on the collision risk value, it is determined whether the moving body needs to take avoidance action. If it is determined that avoidance action is necessary, an avoidance route is set that deviates from the planned route and the bearing of the avoidance end point is a predetermined end bearing.

[0022] Here, the end point direction may be set to a direction that matches the direction of movement of the mobile body at the avoidance start position where the mobile body starts avoidance from the planned route, or it may be set to a direction that matches the direction of the mobile body at a selected position on the planned route where the mobile body has not yet navigated, a direction that matches the direction from the avoidance start position where the mobile body starts avoidance from the planned route toward the destination, or a direction that matches the direction toward a selected position on the planned route where the mobile body has not yet navigated.

[0023] The route planning method of the present invention may further generate one or more potential avoidance route patterns between the avoidance start position and the avoidance end point, and select an avoidance route from one or more potential avoidance route patterns based on the collision risk value calculated for each of the one or more potential avoidance route patterns.

[0024] The route planning method of the present invention may further calculate the avoidance distance between the avoidance start point and the avoidance end point when the moving body navigates one or more potential avoidance route patterns, and select an avoidance route from the one or more potential avoidance route patterns based on the collision risk value and the avoidance distance of the one or more potential avoidance route patterns.

[0025] The route planning method of the present invention may further calculate a congestion risk value indicating the degree of simultaneous approach to multiple obstacles based on a collision risk value between the moving body and each of the multiple obstacles, determine whether the moving body needs to take avoidance based on the congestion risk value in addition to the collision risk value, and set an avoidance route if the avoidance necessity determination unit determines that avoidance is necessary. Furthermore, the avoidance distance between the avoidance start point and the avoidance end point when the mobile body navigates along one or more potential avoidance route patterns may be calculated, and an avoidance route may be selected from the one or more potential avoidance route patterns based on the collision risk value, congestion risk value, and avoidance distance of the one or more potential avoidance route patterns.

[0026] The computer program of the present invention includes the following executable instructions, which, when executed by a computer, cause the computer to acquire planned route information indicating a planned route for a moving body, acquire moving body information including the position, direction of movement, and speed of the moving body, and acquire obstacle information including the position, direction of movement, and speed of one or more obstacles around the moving body, calculate a collision risk value indicating the risk of collision between the moving body and the obstacle based on the moving body information and the obstacle information, determine whether the moving body needs to take avoidance based on the collision risk value, and, if it is determined that avoidance is necessary, set an avoidance route that deviates from the planned route and whose end point bearing is a predetermined end point bearing. [Effects of the Invention]

[0027] When multiple obstacles are detected on the planned route, the route planning system of the present invention compares the collision risk between the original planned route and an avoidance route that is set ahead of the current or predicted position of the moving body, and can choose whether to take avoidance action based on the results, allowing moving bodies such as the ship to navigate safely. [Brief explanation of the drawings]

[0028] Embodiments of the present invention are best understood by reference to the drawings. The following description is intended to be exemplary only and merely illustrates certain selected embodiments of devices, systems, and processes consistent with the subject matter claimed herein, where like parts are designated with like numerals throughout. [Figure 1] 1 is a block diagram showing the configuration of a route planning system for safely navigating a moving body (or own ship) according to an embodiment of the route planning system of the present invention. [Figure 2A] 1 illustrates an area surrounding a vehicle according to one embodiment of the route planning system of the present invention. [Figure 2B] 1 illustrates an area surrounding a vehicle according to one embodiment of the route planning system of the present invention. [Figure 3] FIG. 3 is a block diagram showing a collision avoidance route setting unit in one embodiment of the route planning system of the present invention. [Figure 4] 1 shows a plurality of potential avoidance route patterns generated for an own ship by one embodiment of the route planning system of the present invention. [Figure 5] 1 illustrates the determination of a collision risk value associated with a planned route according to one embodiment of the route planning system of the present invention. [Figure 6] 10 illustrates the determination of a collision risk value when an own ship approaches an obstacle according to an embodiment of the route planning system of the present invention. [Figure 7] This shows the relationship between the time to the closest point between the ship and an obstacle (another ship, etc.) and the collision risk value. [Figure 8A] 10 illustrates the determination of a collision risk value when an own ship approaches an obstacle according to another embodiment of the route planning system of the present invention. [Figure 8B] 10 illustrates the determination of a collision risk value when the own ship approaches an obstacle according to yet another embodiment of the route planning system of the present invention. [Figure 9] 10 shows a graph depicting the correlation between collision risk value and route length for each potential avoidance route pattern according to yet another embodiment of the route planning system of the present invention. [Figure 10] 10 illustrates a table depicting a plurality of potential avoidance routes and corresponding collision risk values, route lengths, and travel distances for each potential avoidance route, according to yet another embodiment of the route planning system of the present invention. [Figure 11] 10 shows calculation of a collision risk value based on the latest moving object information and the latest obstacle information according to yet another embodiment of the route planning system of the present invention. [Figure 12] 10 shows calculation of a collision risk value based on the latest moving object information and the latest obstacle information according to yet another embodiment of the route planning system of the present invention. [Figure 13] 1 illustrates determining the endpoint directions of multiple potential avoidance route patterns according to one embodiment of the route planning system of the present invention. [Figure 14] 1 shows how an avoidance route for the own ship is determined according to an embodiment of the route planning system of the present invention. [Figure 15] 10 illustrates the determination of a new avoidance route for the own ship according to one embodiment of the route planning system of the present invention. [Figure 16A] 10 illustrates determining the direction of the end point of an avoidance route according to yet another embodiment of the route planning system of the present invention. [Figure 16B] 10 illustrates determining the direction of the end point of an avoidance route according to yet another embodiment of the route planning system of the present invention. [Figure 16C] 10 illustrates determining the direction of the end point of an avoidance route according to yet another embodiment of the route planning system of the present invention. [Figure 17] 10 shows how an avoidance route is determined when the own ship approaches multiple obstacles according to another embodiment of the route planning system of the present invention. [Figure 18]FIG. 10 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. [Figure 19A] 10 shows an avoidance route set for the ship to avoid an obstacle according to another embodiment of the route planning system of the present invention. [Figure 19B] 10 shows an avoidance route set for the ship to avoid an obstacle according to another embodiment of the route planning system of the present invention. [Figure 20] This figure shows the change in distance between the ship and other ships when the ship is navigating a planned route in one embodiment of the route planning system of the present invention, and the change in distance between the ship and other ships when the ship is navigating an avoidance route. [Figure 21] FIG. 10 is a diagram showing the relationship between the maximum collision risk when the ship is navigating a planned route and the maximum collision risk when navigating an avoidance route in one embodiment of the route planning system of the present invention. [Figure 22] FIG. 10 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. [Figure 23] 10 is an example of a collision risk assessment unit and its associated components according to another embodiment of the route planning system of the present invention. [Figure 24] FIG. 10 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. [Figure 25] FIG. 10 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. [Figure 26] FIG. 10 is a diagram showing the relationship between the maximum collision risk when a ship navigates a planned route and the maximum collision risk when it navigates an avoidance route in another embodiment of the route planning system of the present invention, and shows that the maximum collision risk is within a second large range of a predetermined base. [Figure 27]FIG. 10 is a diagram showing the relationship between the maximum collision risk when a ship navigates a planned route and the maximum collision risk when it navigates an avoidance route in another embodiment of the route planning system of the present invention, and shows that the maximum collision risk is outside the second large range of the specified base. [Figure 28] FIG. 10 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. [Figure 29] FIG. 10 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. [Figure 30] FIG. 10 is a diagram showing the relationship between the congestion risk when navigating a planned route and the congestion risk when navigating an avoidance route in another embodiment of the route planning system of the present invention. [Figure 31A] 4 shows a flowchart illustrating a route planning method according to another embodiment of the route planning system of the present invention. [Figure 31B] 4 shows a flowchart illustrating a route planning method according to another embodiment of the route planning system of the present invention. [Figure 31C] 4 shows a flowchart illustrating a route planning method according to another embodiment of the route planning system of the present invention. [Figure 31D] 4 shows a flowchart illustrating a route planning method according to another embodiment of the route planning system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Embodiments of the route planning system of the present invention are described herein by way of example, and other exemplary embodiments or features may also be utilized, and changes may be made to other embodiments without departing from the spirit or scope of the subject matter presented herein.

[0030] The exemplary embodiments described herein are not limiting, and it will be readily understood that the features of the invention, as generally described herein and illustrated in the drawings, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are expressly contemplated herein.

[0031] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof.

[0032] Fig. 1 is a block diagram showing the configuration of a route planning system 1 for safely navigating a moving body 200 according to an embodiment of the route planning system of the present invention. Fig. 2A and Fig. 2B are diagrams showing the area around a ship 200 according to an embodiment of the route planning system of the present invention. Hereinafter, the ship 200 moving on water is assumed to be a ship, and therefore will be referred to as the ship 200 as appropriate.

[0033] The route planning system 1 can be installed on the ship 200 itself to navigate the ship 200 from the departure point to the destination. Once the voyage has begun, the route planning system 1 monitors whether the ship 200 is properly navigating along a planned route 202, which is the route the ship 200 should take between the departure point and the destination. The route planning system 1 may be installed on the ship 200 to navigate from the ship's origin position to the destination position, or may be installed in a data center installed on land via a satellite communication system or the like.

[0034] Once the ship 200 begins sailing along the planned route 202, which is the route the ship 200 should follow, the ship 200 must be monitored to ensure safe navigation while sailing between the departure point and the destination. The voyage planning system 1 is used to safely navigate the ship 200 by avoiding collisions with surrounding obstacles, such as other ships or other targets (hereinafter referred to as "obstacles," "other ships," or "targets," as appropriate) that pose obstacles to the ship 200's navigation, landforms such as land or shallow waters, and other targets.

[0035] A ship operator operating the ship 200, i.e., a user operating the ship, navigates the ship 200 along a planned route 202 with the support of the route planning system 1. In one embodiment of the route planning system of the present invention, as shown in Figures 2A and 2B, the planned route 202 is a route that the ship 200 should follow to navigate and safely reach its destination.

[0036] The route planning system 1 includes a route planning unit 2, a Global Navigation Satellite System (GNSS) 3, one or more sensor units 4, a processing circuit 5, a navigation control unit 6, and a display unit 7.

[0037] The route planning unit 2 is configured to store a plurality of routes for the navigation of the own ship 200. In this embodiment, a user can operate various peripheral devices operatively coupled to the route planning system 1 to perform various functions in accordance with the functions of the route planning system of the present invention. For example, the user can provide various types of instructions regarding the origin position and destination position for the navigation of the own ship 200 to the route planning system 1 by operating peripheral devices such as a keyboard and / or a mouse.

[0038] The route planning unit 2 can provide multiple routes for the ship 200 to navigate from the source location to the destination location based on information such as the source location of the ship 200 and the destination location obtained from the user. In this embodiment, each route from the multiple routes can be associated with route information including at least one of travel date and time, weather conditions, tidal conditions, etc. The route planning unit 2 accepts input from the user regarding the selection of a route as the planned route 202 from among multiple routes for the ship 200 to navigate from the departure point to the destination. In this embodiment, the user selects the planned route 202, but in other embodiments, the route planning unit 2 may automatically select an optimal route based on current weather conditions, navigation time, tidal conditions, etc.

[0039] The route planning system 1 safely navigates the ship 200 from the departure point to the destination along the planned route 202, using information associated with the ship 200 and one or more obstacles around the ship 200. The GNSS 3 acquires moving object information including the position, moving direction, and moving speed of the ship 200 based on information obtained from satellites.

[0040] The one or more sensor units 4 acquire obstacle information including the position, movement direction, and movement speed of an obstacle 204 that may impede the navigation of the ship 200. The sensor unit 4 may correspond to one or more conventional marine electronic devices, and specifically, various sensors are envisioned, such as a radar device, a light detection and ranging device (LIDAR), a acoustic navigation and ranging device (SONAR), an automatic identification system (AIS) receiver, an image sensor installed on the ship 200, etc. In this embodiment, the obstacle information includes one or more pieces of information detected by the radar device, LADAR, SONAR, and image sensor, information about other ships transmitted by an AIS receiver, and information acquired by detecting wireless communications at locations other than the ship 200.

[0041] In one embodiment, the obstacle information may further include information about other moving objects, including at least one of other ships, currents, weather, reefs, and stranded ships. The information about the other moving objects may be obtained in a manner similar to that in which the information about the obstacle 204 is obtained.

[0042] 1, the processing circuit 5 includes a planned route information acquisition unit 51, a moving object information acquisition unit 52, an obstacle information acquisition unit 53, a collision risk value calculation unit 54, a collision risk assessment unit 55, an avoidance route setting unit 56 (also called an avoidance route generation unit), and a direction setting unit 57. Note that each of the above units may be configured to perform all of their functions within a single processing circuit, or may be configured discretely.

[0043] 1 and 2A and 2B, the planned route information acquisition unit 51 is operatively coupled to the route planning unit 2 and can communicate with the route planning unit 2 to acquire a route selected by a user as a planned route 202. The planned route 202 indicates a planned route for the ship 200 on the water. Furthermore, the mobile object information acquisition unit 52 is operatively coupled to the GNSS 3 to receive mobile object information associated with the ship 200 and can communicate with the GNSS 3 at appropriate times. The mobile object information acquisition unit 52 is configured to store the acquired mobile object information.

[0044] The obstacle information acquisition unit 53 is configured to be operatively coupled to and able to communicate with one or more sensor units 4 for receiving obstacle information associated with the obstacle 204, and is further configured to store the obstacle information. In this embodiment, the moving object information acquisition unit 52 periodically acquires moving object information of the ship 200, and the obstacle information acquisition unit 53 periodically acquires obstacle information of the obstacle 204. Note that the information acquisition cycle and timing of the moving object information acquisition unit 52 and the information acquisition cycle of the obstacle information acquisition unit 53 may be the same, but do not necessarily have to match.

[0045] The collision risk value calculation unit 54 is operatively coupled to and communicates with the planned route information acquisition unit 51, the moving body information acquisition unit 52, and the obstacle information acquisition unit 53. The collision risk value calculation unit 54 acquires the route selected by the user as the planned route 202, the moving body information of the ship 200, and the obstacle information of the obstacle 204.

[0046] Furthermore, the collision risk value calculation unit 54 calculates a collision risk value related to the planned route 202 based on the moving body information and obstacle information. The collision risk value is calculated based on the positions, movement direction, and speed of the own ship 200 and the obstacle 204. The collision risk value indicates the degree of collision risk between the own ship 200 and the obstacle 204.

[0047] In this embodiment, the collision risk value indicates the degree of collision risk between the own ship 200 and an obstacle among multiple obstacles. In one example, if the obstacle 204 navigates along the assumed unnavigated route 206, while the own ship 200 continues to navigate along the assumed unnavigated planned route 202, the route 206 and the planned route 202 will interfere with each other at the points shown in Figures 2A and 2B. This means that the collision risk between the own ship 200 and the obstacle 204 is high, and therefore the collision risk value will also be high.

[0048] Furthermore, the collision risk assessment unit 55 is operatively coupled to the collision risk value calculation unit and is configured to communicate with and receive the collision risk value from the collision risk value calculation unit 54. In this embodiment, the collision risk assessment unit 55 is configured to determine the need for avoidance based on a comparison of the collision risk value with a threshold value.

[0049] The collision risk assessment unit 55 is configured to determine whether the ship 200 should continue navigating the planned route 202 or should avoid the planned route 202, based on the collision risk value if the ship 200 continues navigating the planned route 202. In other words, the collision risk can be determined by assessing the collision risk value.

[0050] If the collision risk is high, the ship 200 needs to avoid the planned route 202. In one example, when the collision risk assessment unit 55 determines, based on the collision risk value, that the ship 200 needs to avoid the planned route 202, the route planning system 1 issues a control signal to the navigation control unit 6 to cause the ship 200 to navigate along another route 208, i.e., an avoidance route, with the current position of the ship 200 as the avoidance start point 210, as shown in Figure 2 .

[0051] The avoidance route setting unit 56 is operatively coupled to the collision risk assessment unit 55 and can communicate with the collision risk assessment unit. The avoidance route setting unit 56 sets an avoidance route 212 in place of the planned route 202 ahead of the current position 210 as a reference point for the ship 200, i.e., using this as the starting point of the avoidance route.

[0052] In this embodiment, when the collision risk assessment unit 55 determines that collision avoidance is necessary, the avoidance route setting unit 56 determines an avoidance route 212 that is different from the planned route 202. The ship 200 is directed toward an end point heading that serves as a reference heading at the end point of the collision avoidance route. In this embodiment, the end point of the collision avoidance route does not necessarily have to be located on the planned route 202.

[0053] 2A and 2B, when an obstacle 204 is detected on the planned route 202 of the ship 200, the avoidance route setting unit 56 first calculates a collision risk value to measure the degree of collision risk due to the obstacle, and determines whether avoidance is necessary by comparing it with a collision risk threshold. If it is determined that avoidance is necessary, the avoidance route setting unit 56 sets the avoidance route 212 so that the collision risk value related to the avoidance route 212 is equal to or less than the threshold.

[0054] The collision risk threshold used to determine the risk of collision if the ship continues to navigate the planned route 202 and the collision risk threshold used when setting an avoidance route do not necessarily have to be the same. In other words, for example, the collision risk threshold used when setting an avoidance route may be set higher than that used to determine whether or not avoidance is necessary, but in this embodiment they are set to the same value.

[0055] In this embodiment, the generated avoidance route 212 is the current position of the ship 200 where the ship 200 starts avoiding collision, starting from the avoidance start point 210. However, the avoidance start point 210 is not necessarily limited to the current position of the ship 200, and may be an unnavigated position on the planned route 202. The user operating the ship 200 can navigate the ship 200 along the generated avoidance route 212 to avoid collision with the obstacle 204.

[0056] When the ship 200 is navigating the avoidance route 212, the collision risk value calculation unit 54 can regenerate the avoidance route 212 even if the collision risk value is equal to or less than a predetermined threshold. In one scenario, the movement of the obstacle 204 changes the surrounding situation, which changes the collision risk value, and the previously set avoidance route 212 may become a long route.

[0057] In this embodiment, the set avoidance route 212 is fed back to the collision risk value calculation unit 54, and the collision risk value calculation unit 54 calculates a collision risk value related to the avoidance route 212. Furthermore, the collision risk assessment unit 55 determines whether the collision risk value of the avoidance route 212 is equal to or less than a predetermined threshold, and decides whether the ship 200 can continue to navigate the avoidance route 212.

[0058] The avoidance route setting unit 56 may acquire avoidance route information generated outside the ship 200 via wireless communication such as satellite communication, or may acquire avoidance route information regarding the avoidance route set by the avoidance route setting unit 56.

[0059] The avoidance route pattern generation unit 562 in the avoidance route setting unit 56 generates one or more potential avoidance route patterns between the avoidance start point 210 and an end point located off the planned route 202, the end point of which has a predetermined end point orientation and is different from the planned route 202.

[0060] In this embodiment, the direction setting unit 57 is coupled to the avoidance route setting unit 56. The direction setting unit 57 receives the planned route 202 from the planned route information acquisition unit 51 and receives the moving body information from the moving body information unit 52. Furthermore, the direction setting unit 57 determines the direction (or "bearing") of the end point of each potential avoidance route pattern from among the multiple potential avoidance route patterns, based on the planned route and the moving body information.

[0061] In this embodiment, the direction setting unit 57 determines the position of the ship 200 at the start of collision avoidance based on the planned route 202. The direction setting unit 57 also acquires the direction of the ship 200 based on the moving body information. Furthermore, the direction setting unit 57 determines the direction of the end point of each potential collision avoidance route pattern from a plurality of potential collision avoidance route patterns based on the position and direction of the ship 200.

[0062] At the position where the ship 200 starts to deviate from the planned route 202 (referred to as the "avoidance start point"), the ship 200 is in the same direction as the planned route 202 or the direction in which the ship 200 is actually traveling. The direction at the end point of each potential avoidance route pattern from multiple potential avoidance route patterns (the direction of the avoidance end point, hereinafter referred to as the "end point direction") is parallel to the direction indicated by the planned route 202 at a selected position of an untraveled portion on the planned route 202. The end point direction may be set to match the direction from the avoidance start point toward the destination, or may be set to match the direction from the avoidance start point toward a selected location on the untraveled planned route 202, and can be selected as appropriate.

[0063] The collision avoidance route setting unit 56 is configured to acquire the end point direction corresponding to each potential collision avoidance route pattern from the direction setting unit 57. Furthermore, the collision avoidance setting unit 56 selects one potential collision avoidance route pattern (i.e., the collision avoidance route to be taken) that is optimal based on predetermined conditions from the multiple potential collision avoidance route patterns, based on the direction of the end point of each potential collision avoidance route pattern.

[0064] Continuing explanation will be made with reference to Figures 1 and 2A and 2B. The navigation control unit 6 is operatively coupled to the avoidance route generation unit and can communicate with it, and monitors and controls the navigation of the ship 200 based on a determination of whether the ship 200 should avoid the planned route 202 or continue to navigate the planned route 202. To control the navigation of the ship 200 (navigation), the navigation control unit 6 can control the position, movement direction, and speed of the ship 200. If it is determined that the ship 200 needs to avoid the planned route 202, the navigation control unit 6 controls the navigation (navigation) of the ship 200 based on this determination so that the ship 200 follows a route different from the current planned route 202, such as an avoidance route 208.

[0065] The display unit 7 is arranged on the ship 200, and includes a collision risk assessment unit 55 on the ship 200 as a vessel equipment unit for purposes described below, or is electrically connected to the collision risk assessment unit 55 on the ship 200, and displays a planned route 202 that the ship 200 should navigate. Furthermore, when the ship 200 needs to avoid the planned route 202, the display unit 7 displays an avoidance route 208 that the ship 200 should navigate to avoid a collision with an obstacle 204. This allows the ship operator to avoid a collision with the obstacle 204 and navigate the ship 200 safely.

[0066] The display unit 7 can be configured, for example, as a display screen that constitutes part of a navigation support device referenced by the ship operator, i.e., the user, who operates the ship 200. However, the display unit 7 is not limited to the above configuration, and may be, for example, a display screen of a portable computer carried by an assistant to the ship operator who monitors the surrounding conditions from the ship 200, a display screen for viewing by passengers in the passenger cabins of the ship 200, or a display unit of a head-mounted display such as wearable glasses worn by passengers.

[0067] In this embodiment, the moving body information acquisition unit 52 is configured to periodically acquire moving body information, and the obstacle information acquisition unit 53 is configured to periodically acquire obstacle information. Furthermore, the collision risk value calculation unit 54 is configured to periodically calculate a collision risk value. The collision risk assessment unit 55 is configured to periodically determine whether or not collision avoidance is necessary. Furthermore, the collision avoidance route setting unit is configured to periodically set a collision avoidance route when the collision risk assessment unit determines whether or not collision avoidance is necessary.

[0068] Fig. 3 is a block diagram showing an avoidance route generation unit according to an embodiment of the route planning system of the present invention. Fig. 4 shows a plurality of potential avoidance route patterns generated for the own ship according to an embodiment of the route planning system of the present invention.

[0069] In this embodiment, the collision avoidance route setting unit 56 includes a potential collision avoidance route pattern generation unit 562, a route pattern evaluation unit 564, and a collision avoidance route selection unit 566. The potential collision avoidance route pattern generation unit 562 is operatively coupled to the direction setting unit 57 and is capable of mutual communication with the direction setting unit 57. The potential collision avoidance route pattern generation unit 562 generates a plurality of potential collision avoidance route patterns 402, each with the position of the ship 200 as the collision avoidance start point 210.

[0070] As shown in Fig. 4, a plurality of avoidance route patterns 402 are candidate avoidance route patterns for the avoidance route 212 from the avoidance start point 210 to the destination of the ship 200, and are hereinafter referred to as potential avoidance route patterns. The potential avoidance route pattern generation unit 562 generates a plurality of potential avoidance route patterns 402 when there is a high risk of collision between the ship 200 and an obstacle 204. In the example shown here, a first plurality of points are generated in a fan shape around the avoidance start point 210, and a second plurality of points are generated in a fan shape from each of the first plurality of points. Although a fan shape is shown here as an example, other patterns may be used.

[0071] The plurality of potential avoidance route patterns 402 can be generated by sequentially connecting the first plurality of points and the second plurality of points. In this embodiment, the potential avoidance route pattern generation unit 562 is configured to generate a plurality of potential avoidance route patterns different from the planned route 202 between the avoidance start point 210 on the unnavigated planned route and an end point distant from the planned route 202.

[0072] The route pattern evaluation unit 564 is operatively coupled to the potential avoidance route pattern generation unit and is capable of mutual communication with the potential avoidance route pattern generation unit 562. The route pattern evaluation unit 564 determines a collision risk value for each potential avoidance route pattern of the plurality of potential avoidance route patterns 402.

[0073] The avoidance route selection unit 566 is operatively coupled to the route pattern evaluation unit 564 and is in communication with the route pattern evaluation unit. The avoidance route selection unit 566 is configured to select a potential avoidance route pattern from the plurality of potential avoidance route patterns 402 to be set as the avoidance route 212 based on the collision risk value determined for each potential avoidance route pattern of the plurality of potential avoidance route patterns. The potential avoidance route pattern is the avoidance route 212 that the own ship 200 should navigate, and in this embodiment, the avoidance route 212 is an optimal route for the own ship 200.

[0074] In this embodiment, the route pattern evaluation unit 564 is further configured to determine a route length of each potential avoidance route pattern from the plurality of potential avoidance route patterns 402, and determines the route length of each potential avoidance route pattern based on the collision risk value determined for each potential avoidance route pattern. Furthermore, the avoidance route selection unit 566 is configured to select a potential avoidance route pattern from the plurality of potential avoidance route patterns 402 based on the determined collision risk value and the route length of each potential avoidance route pattern of the plurality of potential avoidance route patterns 402.

[0075] When the collision risk value is small, the collision avoidance route selection unit 566 selects an optimal potential collision avoidance route pattern for the ship 200. The smaller the collision risk value, the longer the detour route. As a result, the collision avoidance route selection unit 566 selects the optimal potential collision avoidance route pattern as the collision avoidance route 212 based on the collision risk value and the route length of each potential collision avoidance route pattern. The collision avoidance route selection unit 566 may be configured to select an appropriate collision avoidance route when it is decided to switch from the planned route 202 to the collision avoidance route 212.

[0076] In this embodiment, if there is no avoidance route whose collision risk value and congestion risk value are below the threshold, the avoidance route setting unit 56 is configured to release the restriction on the end point direction of the avoidance route and set a new avoidance route whose collision risk value and congestion risk value are below the threshold. In this embodiment, it is assumed that there is no avoidance route among multiple avoidance route patterns whose collision risk value and congestion risk value are each below the threshold. In this embodiment, the avoidance route setting unit 56 sets a new avoidance route whose collision risk value and congestion risk value are below the threshold.

[0077] In this embodiment, the avoidance route setting unit 56 is configured to select an avoidance route from a plurality of potential avoidance route patterns 402 in which the travel distance of the ship 200 is the smallest among the plurality of potential avoidance route patterns, and in which the maximum collision risk value and congestion risk value are below thresholds.

[0078] 5 is a diagram showing how a collision risk value for a planned route 202 is determined in accordance with one embodiment of the route planning system of the present invention. The collision risk value calculation unit 54 determines the collision risk value for the planned route 202 based on moving body information and obstacle information. The collision risk value for the planned route 202 can be determined based on the positions, moving direction, and speed of the ship 200 and the obstacle 204.

[0079] The collision risk value calculation unit 54 is further configured to determine the closest approach distance DC between the ship 200 and the obstacle 204 and at least one of the closest approach distances Dx and Dy in a specific direction based on the moving body information and the obstacle information.

[0080] In this embodiment, the closest approach distance DC is the distance between the current position of the ship 200 and the closest point of approach 502. The vertical closest approach distance Dx is the distance between the current position of the ship 200 and the closest vertical point of approach 504, and the horizontal closest approach distance Dy is the distance between the current position of the ship 200 and the closest horizontal point of approach 506.

[0081] The collision risk value calculation unit 54 calculates the closest approach distances DC, Dx, and Dy when the ship 200 and the obstacle 204 approach each other based on the positional relationship between the ship 200 and the obstacle 204, the relative speed between the ship 200 and the obstacle 204, and the direction and speed of movement between the ship 200 and the obstacle 204.

[0082] The collision risk value calculation unit 54 calculates a collision risk value for the planned route 202 based on at least one of the closest approach distance DC between the ship 200 and the obstacle 204 and the closest approach distances Dx and Dy in a specific direction.

[0083] In this embodiment, if the closest distance DC is equal to or less than a predetermined distance, the collision risk assessment unit 55 determines that the collision risk is high, and the ship 200 needs to navigate the avoidance route 212 to avoid the obstacle 204. On the other hand, if the closest distance DC is equal to or greater than a predetermined distance, the collision risk assessment unit 55 determines that the collision risk is low, and the ship 200 may continue on the planned route 202.

[0084] In another embodiment, if the closest distance in the specific direction Dx or Dy is equal to or less than a predetermined distance, the collision risk assessment unit 55 determines that the collision risk is high, and therefore the ship 200 needs to navigate the avoidance route 212 to avoid the obstacle 204. On the other hand, if the closest distance in the specific direction Dx or Dy is equal to or greater than the predetermined distance, the collision risk assessment unit 55 determines that the collision risk is low, and the ship 200 may continue on the planned route 202.

[0085] In this embodiment, the collision risk value may be calculated by identifying the positional relationship between the ship 200 and the obstacle 204 based on at least one of the closest distance in the vertical direction Dx and the closest distance in the horizontal direction Dy. Because the obstacle 204 crosses in front of the ship 200, the collision risk between the ship 200 and the obstacle 204 increases.

[0086] In this embodiment, the collision risk value calculation unit 54 determines the time TC required for the ship 200 to cross the closest distance DC, and determines a collision risk value related to the planned route 202 based on the closest distance DC and the time TC required for the ship 200 to cross the closest distance DC. The time TC required for the ship 200 to cross the closest distance DC is calculated based on moving object information and obstacle information.

[0087] In a route where the collision risk value is calculated based on the closest distance DC between the own ship 200 and the obstacle 204, the collision risk value increases even if the time it takes for the own ship 200 to approach the obstacle 204 is very long. As a result, the own ship 200 must avoid the planned route 202 to avoid a possible collision with the obstacle 204 after sailing for a while. Therefore, in one embodiment, the collision risk value associated with the planned route 202 is determined taking into account the closest distance DC between the own ship 200 and the obstacle 204 and the time TC required for the own ship 200 to reach the closest point 302.

[0088] In one embodiment, the collision risk value associated with the planned route 202 is determined based on the following equation (1): Collision risk value = mAx(Dx,Dy)*TC (1)

[0089] FIG. 6 illustrates the determination of a collision risk value when own ship 200 approaches an obstacle 204 according to this embodiment of the route planning system of the present invention.

[0090] As the obstacle 204 enters an elliptical region 602 around the own ship 200, the collision risk value increases. In one example, the elliptical region 602 is determined based on the area within 1.5 nautical miles (NM) ahead, 0.2 NM behind, and 0.5 NM to the side of the own ship 200. As the distance between the own ship 200 and the obstacle 204 decreases, the collision risk value increases. Therefore, it can be said that the collision risk value is roughly inversely proportional to the distance between the own ship 200 and the obstacle 204.

[0091] Figure 6 further shows the relationship between the collision risk value and the vertical distance between the ship 200 and the obstacle 204, and the relationship between the collision risk value and the horizontal distance between the ship 200 and the obstacle 204. As an example, the collision risk values for the closest vertical and horizontal distances Dx and Dy are shown in Figure 6. Based on the closest distance DC between the ship 200 and the obstacle 204, the threshold value Dt is determined so that the collision risk value is high when the closest distance DC between the ship 200 and the obstacle 204 is equal to or less than the threshold value Dt.

[0092] 7 is a diagram showing the relationship between the time TC required for the ship 200 to pass the closest distance DC and the collision risk value. The shorter the time TC, the higher the collision risk value. In one example, when the time TC is equal to or shorter than a predetermined time, the collision risk value is determined to be high, i.e., the maximum value 1.

[0093] 8A shows the determination of a collision risk value when the own ship 200 approaches an obstacle 204 according to another embodiment of the route planning system of the present invention. An obstacle bumper area 802 of the obstacle 204 is determined based on the position, movement direction, and speed of the obstacle 204, i.e., the ship. The obstacle bumper area 802 of the obstacle 204 is located on the predicted future path 206 of the obstacle 204 based on the movement direction of the obstacle 204. The obstacle bumper area 802 of the obstacle 204 includes the obstacle 204 and the area surrounding the obstacle 204. The obstacle bumper area 802 of the obstacle 204 may be determined based on a safe passing distance 804, which is an allowable closest approach distance to prevent a collision.

[0094] The obstacle bumper area 802 corresponds to a no-approach area or a collision risk area, and allows simultaneous recognition of the direction and distance of a collision between the ship 200 and the obstacle 204. The closest point of approach between the ship 200 and the obstacle 204 in the vertical or lateral direction 806 or 808 (closest point of approach to the obstacle 204) is determined based on the moving object information and the obstacle information. If the closest point of approach between the ship 200 and the obstacle 204 in the vertical or lateral direction 806 or 808 is outside the obstacle bumper area 802, there is no risk of collision.

[0095] As shown in FIG. 8A, in this embodiment, neither the closest point of approach in the vertical direction 806 for the Rx distance nor the closest point of approach in the lateral direction 808 for the Ry distance from the obstacle 204 is inside the obstacle bumper area 802, so there is no risk of collision.

[0096] In this embodiment, the collision risk value calculation unit 54 calculates the time required for the ship 200 to enter the obstacle bumper area 802 based on the relative speed between the ship 200 and the obstacle 204. The collision risk value calculation unit 54 further calculates a collision risk value related to the planned route 202 based on the time required for the ship 200 to enter the obstacle bumper area 802.

[0097] 8B shows the determination of a collision risk value when the own ship 200 approaches an obstacle 204 according to yet another embodiment of the route planning system of the present invention. The moving object bumper region 810 of the own ship 200 is determined based on the position, movement direction, and speed of the own ship 200. The moving object bumper region 810 of the own ship 200 is located on the planned route 202 of the own ship 200 based on the movement direction of the own ship 200, and includes the own ship 200 and the area surrounding the own ship 200. Based on this moving object information and obstacle information, the closest point (relative to the own ship 200) between the own ship 200 and the obstacle 204 in the vertical direction 504 or lateral direction 506 is calculated. If the closest point between the own ship 200 and the obstacle 204 in the vertical direction 504 or lateral direction 506 is outside the moving object bumper region 810, there is no risk of collision.

[0098] 8B, in this embodiment, the closest point in the longitudinal direction 504 at the distance Rx from the own ship 200 is within the moving object bumper area 810, so there is a risk of collision. If the own ship 200 continues to navigate in the current movement direction along the planned route 202, there is a risk of entering the obstacle bumper area 802 of the obstacle 204 and colliding with it.

[0099] In this embodiment, the collision risk value calculation unit 54 determines the time required for the moving object bumper region 810 to enter the obstacle bumper region 802 based on the relative speed between the ship 200 and the obstacle 204. The collision risk value calculation unit 54 further determines a collision risk value associated with the planned route 202 based on the time required for the moving object bumper region 810 to enter the obstacle bumper region 802.

[0100] 9 shows a graph 900 illustrating the correlation between collision risk value and route length for each potential avoidance route pattern according to yet another embodiment of the route planning system of the present invention. The collision risk value is represented on the X-axis, and the route length (in nm) is represented on the Y-axis. Assuming that a collision risk value of 0.4 or less is required for safe navigation and avoidance of collisions, there are at least six potential avoidance route patterns generated by the potential avoidance route pattern generator 562.

[0101] In one example, potential avoidance route pattern D has the smallest collision risk value, but the route length of each potential avoidance route pattern D is long. Furthermore, potential avoidance route pattern F has a shorter route length compared to potential avoidance route pattern D, but the collision risk value is close to 0.4.

[0102] Furthermore, potential avoidance route pattern E has a smaller collision risk value than potential avoidance route pattern F, and the route length of each potential avoidance route pattern E is shorter than potential avoidance route pattern D. Therefore, in this embodiment, the avoidance route selection unit 566 may select potential avoidance route pattern E as the optimal potential avoidance route pattern.

[0103] In one situation, if there is no potential avoidance route pattern whose collision risk value is equal to or less than a predetermined threshold, none of the multiple potential avoidance route patterns is selected. In this case, the route planning system 1 can provide at least one of a signal indicating that no avoidance route pattern exists and / or an error message indicating that no avoidance route pattern exists.

[0104] 10 shows a table 1000 that lists multiple potential avoidance routes and the corresponding collision risk value, route length, and travel distance of each potential avoidance route. The avoidance route selection unit 566 selects an avoidance route pattern from multiple potential avoidance route patterns 402 based on the collision risk value, route length, and travel distance of each potential avoidance route. In one example, the avoidance route selection unit 566 can select potential avoidance route pattern E because it has the optimal collision risk value, path length, and travel distance compared to potential avoidance route patterns A, B, D, and F, as shown in table 1000.

[0105] 11 and 12 show calculation of a collision risk value based on the latest moving object information and the latest obstacle information according to one embodiment of the route planning system of the present invention. The surrounding area of the ship 200 changes as the ship 200 navigates. The moving object information acquisition unit 52 is configured to periodically receive moving object information at regular intervals during a first period 1102. Similarly, the obstacle information acquisition unit 53 is configured to periodically acquire obstacle information at regular intervals during a second period 1104. The avoidance route generation unit 56 is further configured to periodically generate an updated avoidance route based on the current position of the ship 200. The current position of the ship 200 is assumed to be a new avoidance starting point for the updated avoidance route.

[0106] In this embodiment, the avoidance route generation unit 56 is further configured to periodically generate the latest avoidance route based on the updated acquired mobile body information and the updated acquired obstacle information at regular intervals during a third period 1106, i.e., the third period 1106 is shorter than the second period 1104 and longer than the first period 1102, as shown in FIG. 11 .

[0107] The mobile object information acquisition terminal unit 52 acquires mobile object information during a first period 1102 that is shorter than a third period 1106. The collision risk at timing t2 is calculated based on the mobile object information acquired at timings t1 and t2 and the obstacle information acquired at timings surrounded by circles 1108 and 1110. Note that it is preferable to acquire the mobile object information and obstacle information periodically, because the more frequently the information is acquired, the more times a collision risk value can be determined based on the latest mobile object information and the latest obstacle information.

[0108] 12 , in yet another embodiment, the avoidance route generation unit 56 periodically generates the latest potential avoidance route pattern based on the updated acquired moving object information and the updated acquired obstacle information during a third period 1206 that is longer than the first period 1202 and the second period 1204. The collision risk at timing t2 is calculated based on the moving object information and obstacle information acquired at timing t2 that is surrounded by a circle 1208. In FIG. 12 , the obstacle information acquisition unit 53 may acquire obstacle information during the second period 1204 that is shorter than the third period 1206.

[0109] Ideally, it is desirable to obtain both moving object information and obstacle information at a high frequency and calculate the collision risk value based on the most recent information. For example, the collision risk value calculated at time t1 does not indicate a risk of collision, but the value calculated at time t2 indicates a high probability of collision. Therefore, an avoidance route is generated, and the ship 200 must navigate along the avoidance route. The collision risk value calculated at time t3 still indicates a risk of collision with the obstacle, but the avoidance route reduces the collision risk at time t4.

[0110] 13 is a diagram showing how the direction of the end point of a plurality of potential avoidance route patterns is determined according to one embodiment of the route planning system of the present invention. In this embodiment, the direction at the time (i.e., the first timing) to which the ship 200 should deviate in order to avoid a collision between the ship 200 and an obstacle 204 attempting to cross the planned route 202, i.e., the direction indicated by the dashed line, is determined. In addition, a plurality of potential avoidance route patterns 1302 are generated so that the direction of the end point of the avoidance route coincides with the direction indicated by the dotted line. In this embodiment, the direction of the end point of each potential avoidance route pattern from the plurality of potential avoidance route patterns 1302 is determined based on the planned route 202 and moving object information.

[0111] In this embodiment, the direction of the end point of each potential avoidance route pattern from the multiple potential avoidance route patterns 1302 is parallel to the direction of the ship 200 at the position where the ship 200 starts to deviate from the planned route 202. The direction at the end point of the avoidance route can be set appropriately depending on the situation, and may be parallel from the position where the ship 200 starts to avoid collision at a selected point on the unnavigated planned route toward the destination, or it may be parallel from the position where the ship 200 starts to avoid collision toward a selected point on the unnavigated planned route.

[0112] 14 shows the determination of an avoidance route for the own ship according to one embodiment of the route planning system of the present invention. In this embodiment, the potential avoidance route pattern generation unit 562 generates a plurality of potential avoidance route patterns 1402 different from the planned route 202 between an avoidance start point on an unnavigated planned route and an end point outside the planned route. Furthermore, the route pattern evaluation unit 564 evaluates a collision risk value of each potential avoidance route pattern from the plurality of potential avoidance route patterns 1402. Furthermore, the avoidance route selection unit 566 is configured to select a potential avoidance route pattern as an avoidance route 1404 from the plurality of potential avoidance route patterns based on the collision risk value. In this embodiment, the potential avoidance route pattern is selected as the avoidance route 1404 for the moving object.

[0113] As shown in Figure 14, the route indicated by the solid black line corresponds to the avoidance route 1404. The selected avoidance route 1404 is parallel to the planned route 202 (if it is a straight line). In this embodiment, the selected avoidance route 1404 is at a different position from the original planned route 202, but the ship 200 may navigate the avoidance route 1404 as a new route.

[0114] 15 shows the determination of a new avoidance route for the ship itself according to one embodiment of the route planning system of the present invention. In this embodiment, the route planning system 1 sets an avoidance route different from the planned route 202 to avoid a collision between the ship itself 200 and an obstacle 204. In this embodiment, a second obstacle, i.e., an obstacle 1502, is approaching the avoidance route used by the ship itself 200 for navigation. In order to avoid a collision between the obstacle 1502 and the ship itself 200, multiple new potential avoidance route patterns are generated.

[0115] Furthermore, the collision risk value calculation unit 55 calculates a collision risk value for each new potential collision avoidance route pattern. Based on the collision risk value, the collision avoidance route setting unit 56 selects a new potential collision avoidance route pattern from the plurality of new collision avoidance route patterns as a new collision avoidance route 1504. The new collision avoidance route 1504 is further used by the ship 200 for navigation. In this embodiment, the new collision avoidance route is generated in the same manner as the generation of the collision avoidance route already described in the above-mentioned drawings.

[0116] 16A to 16C generally show the determination of the direction of the end point of an avoidance route according to yet another embodiment of the route planning system of the present invention. In this embodiment, the direction setting unit 57 receives the direction of the planned route 202 and the direction of the own ship 200. In this embodiment, the direction setting unit 57 determines the direction of the end point of each potential avoidance route pattern from a plurality of potential avoidance route patterns 1602 based on the direction of the planned route 202 at the time when the own ship 200 is about to start avoidance, but the direction setting is not limited.

[0117] In this embodiment, the end point of the ship 200 may be determined, and a direction parallel to the planned route 202 may be determined as the direction to the end point of the avoidance route based on the position of the planned route 202. Alternatively, the position of the planned route 202 closest to the end point of the avoidance route may be determined, and the direction of the planned route 202 at this position may be determined as the direction to the end point of the avoidance route.

[0118] In yet another embodiment, the direction of the end point of the avoidance route may be determined to be parallel to the direction of the ship 200 at the position where the ship 200 starts to deviate from the planned route 202. In another embodiment, the direction of the end point of the avoidance route may be determined to be toward the destination from the position where the ship 200 starts to deviate from the planned route 202.

[0119] 16B and 16C, a plurality of potential avoidance route patterns are generated in directions toward a destination or a specific point on a planned route not yet traveled. The direction of the end point of the avoidance route 1604 is determined based on the directions toward the destination or the specific point on a planned route not yet traveled of the plurality of potential avoidance route patterns.

[0120] In another embodiment, the direction of the end point of the avoidance route 1604 may be determined from the position where the ship 200 starts avoidance toward the selected point on the planned route not yet traveled. In another embodiment, the direction of the end point of the avoidance route may be set to be parallel to the direction of the selected point on the planned route not yet traveled.

[0121] 17 illustrates the determination of an avoidance route when the ship approaches multiple obstacles according to another embodiment of the route planning system of the present invention. In this embodiment, multiple obstacles 1704, 1706, 1708, 1710, 1712, etc. are approaching the ship 200 on the planned route 202. In this embodiment, the congestion risk value and maximum collision risk value of each obstacle may be calculated, and the avoidance route may be set based on the collision risk value and maximum collision risk value.

[0122] When there are a large number of obstacles, it may be difficult to set an avoidance route that satisfies the above conditions. In this case, it is possible to avoid a collision between the obstacles and the ship 200 by determining the direction of the end point of the avoidance route so that both risks (i.e., the collision risk value and the maximum collision risk value) are below their respective thresholds. In this embodiment, the avoidance route 1714 can be determined as a new route for the ship 200 to travel. However, the direction of the end point of the avoidance route does not satisfy the conditions already described. The calculation of the maximum collision risk value will be described later.

[0123] 18 is a block diagram showing a route planning system 1 for safely navigating a ship 200 according to another embodiment of the route planning system of the present invention. The route planning system 1 comprises a route planning unit 2, a GNSS 3, one or more sensor units 4, a processing circuit 5, a navigation control unit 6, and a display unit 7. The route planning unit 2, the GNSS 3, and the sensor unit 4 function in the same manner as in the system shown in FIG.

[0124] The processing circuit 5 includes a route planning information acquisition unit 51, a moving body information acquisition unit 52, an obstacle information acquisition unit 53, a collision risk value calculation unit 54, a congestion risk value calculation unit 58, a collision risk assessment unit 55, an avoidance route generation unit 56, and a direction setting unit 57. The route planning information acquisition unit 51, the moving body information acquisition unit 52, the obstacle information acquisition unit 53, the collision risk value calculation unit 54, the collision risk assessment unit 55, the avoidance route generation unit 56, and the direction setting unit 57 function in the same way as the processing circuit shown in FIG.

[0125] 19A and 19B, when obstacles 1904 and 1906 are traveling along predicted future routes 1908 and 1910, respectively, and the ship 200 continues traveling along the planned route 202, the predicted future routes 1908 and 1910 and the ship 200's planned route 202 interfere with each other as shown in the figures, and there is a risk of collision between the ship 200 and both obstacles. In other words, in this embodiment, there is a high risk of multiple collisions associated with the planned route 202, and a high risk of collision between the ship 200 and the multiple obstacles 1904 and 1906.

[0126] 18 , the congestion risk value calculation unit 58 is operatively connected to the collision risk value calculation unit 55. The congestion risk value calculation unit 58 is configured to communicate with the collision risk value calculation unit 55 and receive a plurality of collision risk values associated with a plurality of obstacles 1904 and 1906 along the planned route 202. The congestion risk value calculation unit 58 then determines a congestion risk value associated with the planned route 202 along the current route direction based on the plurality of collision risk values. Here, the congestion risk value indicates the degree of simultaneous approach of a plurality of obstacles to the ship 200 based on the collision risk corresponding to each of the obstacles that pose a collision risk in the congested area.

[0127] As an example of calculating a collision risk value corresponding to a plurality of obstacles 1904, 1906, the congestion risk value calculation unit 58 calculates a congestion risk value corresponding to the planned route 202 based on the logical sum of a plurality of collision risks associated with a plurality of obstacles. In this embodiment, the congestion risk value calculation unit 58 calculates the congestion risk value of the planned route 202 based on the logical sum of a plurality of collision risk values excluding the maximum collision risk value among the plurality of collision risks. In this embodiment, the congestion risk value calculation unit 58 is further configured to calculate the congestion risk value based on the plurality of collision risk values excluding the maximum collision risk value, including a second largest collision risk value among the plurality of collision risk values.

[0128] Here, the term "logical sum" refers to a logical sum based on a logic in which one or both of two propositions in a logical operation are true and both are false. In other words, a logical sum based on the number of logic circuits and the number of binary digits is 1 when one or both of the two inputs is 1 and 0 when both are 0. For example, if there are four obstacles, Obs(1), Obs(2), Obs(3), and Obs(4), and the collision risks are 0.3, 0.5, 0.7, and 0.9, respectively, the maximum collision risk is Obs(4), which is 0.9. The logical sum of the remaining three, Obs(1) to Obs(3), is 0.7. Note that the method of calculating the congestion risk value using logical sum is not limited to the above. The collision risk value of each obstacle may be multiplied by a predetermined coefficient and then the logical sum may be calculated. Alternatively, a risk value corresponding to the distribution of collision risk values of each of multiple obstacles may be predetermined and used as the congestion risk value.

[0129] Figure 20 is a diagram showing the change in distance between the own ship and other ships when the own ship navigates a planned route and the change in distance between the own ship and other ships when the own ship navigates an avoidance route in one embodiment of the route planning system of the present invention. Figure 20 shows the change in distance between the own ship 1904 (solid line) and other ships 1906 (i.e., dashed line) when the own ship 200 navigates for a predetermined time from the avoidance start point where avoidance starts from the planned route 202, and further shows the change in distance between the own ship 1904 (i.e., dotted line) and other ships 1906 (i.e., dotted line) when the own ship 200 navigates for a predetermined time on an avoidance route outside the planned route from the avoidance start point.

[0130] In this embodiment, when the own ship 200 departs from the planned route 202, the other ship 1904 approaches the own ship 200, and the distance between the two ships decreases. At the position indicated by the black circle in Figure 20, the two ships are closest to each other, and then the two ships move away from each other, and the value indicating the distance increases. After that, the other ship 1906 approaches the own ship 200, and even at its closest, the distance is greater than that of the other ship 1904. In other words, the risk of collision with the own ship 200 is low. Therefore, the maximum collision risk on the planned route 202 is calculated based on the state in which the other ships 1904 and 1906 are each closest to the own ship 200.

[0131] On the other hand, when the own ship 200 takes the avoidance route, the other ship 1904 approaches the own ship 200, and the distance between them changes as shown by the dashed line in Figure 20, becoming larger than the distance when the own ship 200 navigates the planned route 202. However, the closest distance when the other ship 1906 approaches is close to the distance indicated by the white circle, which is smaller than the closest distance of the other ship 1904 when the own ship 200 navigates the planned route 202, and therefore the collision risk increases. Therefore, the maximum collision risk value of the avoidance route is calculated based on the state when the other ships 1906, 1904 are closest to each other. This value is larger than the maximum risk value when the own ship 200 navigates the planned route 202.

[0132] Referring to Figure 18, in this embodiment, the collision risk value calculation unit 55 calculates the collision risk value expected on the planned route 202 based on the moving body information of the own ship 200 and the obstacle information of the other ships 1904 and 1906.

[0133] The collision risk value calculation unit 55 is configured to calculate a collision risk value related to obstacles (i.e., other ships 1904 and 1906) when navigating the planned route, based on the moving body information and obstacle information. The position of the own ship 200, a position on the planned route 202, or the current position of the own ship 200 is set as the avoidance start point. Then, in the same way, the collision risk value when navigating the avoidance route for a predetermined period of time starting from the avoidance start point is calculated.

[0134] In the above, referring to Figure 20, it is assumed that the ship 200 starts avoiding collisions from its actual position on the planned route 202, and this is taken as the starting point of avoiding collisions. However, the starting point of avoiding collisions is not limited to this, and since the actual position on the planned route 202 is affected by sea conditions, errors may occur, but such cases are acceptable.

[0135] Furthermore, the starting point of the avoidance action for the ship 200 is not necessarily limited to its current location, but may be any assumed point on the unnavigated route of the planned route 202, or may be a predicted position calculated based on the moving body information of the ship 200 in accordance with the actual position described above.

[0136] Figure 21 is a diagram showing the relationship between the maximum collision risk when the own ship 200 navigates the planned route 202 and the maximum collision risk when the own ship 200 navigates an avoidance route in one embodiment of the route planning system of the present invention. Three cases are shown here. In case 1, the maximum risk value when the own ship 200 navigates the planned route 202 is 0.71, while the maximum risk value for the avoidance route is 0.38, which is smaller than that of the planned route. In case 2, both are 0.52, and in case 3, they are 0.36 and 0.73.

[0137] In Case 1, the maximum collision risk value of the planned route 202 is significantly lower than the maximum collision risk value of the avoidance route, and it can be seen that the collision risk value is lower when navigating the avoidance route than when navigating along the planned route 202. In Case 2, both values are the same, and it can be seen that the collision risk value does not change whether the planned route 202 is moved or switched to the avoidance route. In Case 3, the maximum collision risk value of the avoidance route is slightly higher, and it can be seen that the collision risk value can be reduced by continuing to move along the planned route 202.

[0138] As described above, the route planning system 1 of the present invention can examine whether or not a collision risk value is reduced by an avoidance route set for the following purposes.

[0139] With reference to Figure 22, the following describes how to determine the necessity of changing the navigation route, taking into account the distances from the start point of the avoidance route to the planned route and the avoidance route, in addition to comparing the maximum collision risk.

[0140] Figure 22 is a block diagram showing a route planning system 1 for safely navigating a moving body (own ship) 200, according to another embodiment of the route planning system of the present invention. The difference from Figure 18 is that the embodiment shown in Figure 22 is equipped with a maximum collision risk selection unit 59. The maximum collision risk selection unit 59 selects the obstacle with the maximum collision risk value, i.e., the obstacle with the highest collision risk value, from the collision risk values for each of the multiple obstacles calculated by the collision risk value calculation unit 54. In this embodiment, as described above, the possibility of collision is first evaluated for the obstacle with the maximum collision risk value, and a decision is made as to whether or not avoidance action is required.

[0141] On the other hand, for obstacles other than the obstacle with the maximum collision risk value, a collision risk value indicating the degree to which multiple obstacles approach simultaneously, i.e., a congestion risk value, is evaluated. Therefore, for obstacles with collision risk values other than the maximum collision risk value, the collision risk value is input to the congestion risk value calculation unit 54, and a congestion risk value is calculated.

[0142] In this embodiment, the collision risk value with the obstacle having the maximum collision risk value is evaluated individually, so the maximum collision risk value may be excluded from the calculation of the congestion risk value, but it can also be included. When calculating the congestion risk value by excluding the obstacle having the maximum collision risk value, it is preferable to calculate the congestion risk value by including obstacles with a risk value equal to or less than the maximum risk value.

[0143] When assessing the collision risk, it is more appropriate to calculate the congestion risk value based on the collision risk values of one or more obstacles excluding the obstacle with the maximum collision risk value, and assess the maximum collision risk value and the collision risk value separately. Needless to say, the first priority is to avoid a collision with the obstacle with the maximum collision risk value. The next priority is to consider the collision risk values with other collision risk values, for example, with obstacles including an obstacle with a second collision risk value that is larger, when performing avoidance.

[0144] In this embodiment, the collision risk value calculation unit 54 is configured to calculate a maximum collision risk value for each potential collision avoidance route pattern from the plurality of potential collision avoidance route patterns. The congestion risk value calculation unit 58 is configured to calculate a congestion risk value for each potential collision avoidance route pattern from the plurality of potential collision avoidance route patterns. The collision avoidance route selection unit 56 is configured to select a potential collision avoidance route pattern as an escape route from the plurality of potential collision avoidance route patterns based on the maximum collision risk value and the congestion risk value corresponding to each potential collision avoidance route pattern.

[0145] 23 is an example of the collision risk assessment unit 55 and its related components according to another embodiment of the route planning system of the present invention. In this embodiment, the maximum collision risk value selected by the maximum collision risk selection unit 59 is assessed by comparing it with a predetermined maximum collision risk threshold in the maximum collision risk assessment unit 552 of the collision risk assessment unit 55.

[0146] On the other hand, the collision risk value excluding the maximum collision risk value is input to the congestion risk value calculation unit 58 to calculate the congestion risk value, which is then evaluated by comparing it with a predetermined congestion risk threshold in the congestion risk evaluation unit 554 of the collision risk evaluation unit 55.

[0147] In this embodiment, the collision risk assessment unit 55 determines that there is no collision risk if both the maximum collision risk value and the congestion risk value are equal to or less than predetermined thresholds, and outputs a risk assessment result.

[0148] On the other hand, if the maximum collision risk value and the congestion risk value each exceed a predetermined maximum collision risk threshold, it is determined that there is a collision risk. However, if the maximum collision risk value is below the predetermined threshold, it may be determined that the imminent collision risk is low even if the congestion risk value exceeds the predetermined congestion risk threshold.

[0149] In this way, the collision risk assessment unit 55 may operate in conjunction with the congestion risk value calculation unit 58 to obtain a congestion risk value related to the planned route 202. The collision risk assessment unit 55 further determines whether the own ship 200 should depart from the planned route 202 and take an avoidance route, or whether the own ship 200 should continue to navigate along the planned route 202, based on the congestion risk value when navigating the planned route 202. The potential collision risk value can be determined by evaluating the congestion risk value of the planned route 202. If the congestion risk value is high, the own ship 200 can navigate a different route, such as the avoidance route 212, to avoid a collision with the planned route 202 and the multiple obstacles 1904 and 1906.

[0150] In this embodiment, when the collision risk assessment unit 55 determines based on the congestion risk value that the ship 200 needs to avoid the planned route 202, the route planning system 1 prompts the ship operator to navigate the ship 200 from the current position of the ship 200 or a predicted position where the ship may navigate in the future, that is, the starting reference point (or waypoint) 1902, via the avoidance route 1912, as shown in Figures 19A and 19B. This can be done by various means, such as a warning display on the screen or audio.

[0151] In this embodiment, when the ship 200 is navigating along the planned route 202, the planned route 202 becomes the planned route, but it will be clear to those skilled in the art that the scope of the present invention is not limited to this. In another embodiment, the navigation route when the ship 200 is navigating along the avoidance route 1912 may be the avoidance route 1912, without departing from the scope of the present invention.

[0152] In another embodiment, when the ship 200 is sailing along the avoidance route 1912, the collision risk value calculation unit 54 may calculate multiple collision risk values associated with multiple obstacles 1904, 1906 along the avoidance route 1912 (i.e., the route planned for avoidance) based on moving body information and obstacle information.

[0153] The congestion risk value calculation unit 58 calculates the congestion risk value associated with the avoidance route 1912 based on the multiple collision risk values. For example, as described above, the congestion risk value calculation unit 58 calculates the congestion risk value associated with the avoidance route 1912 based on the logical sum of the multiple collision risk values associated with the multiple obstacles 1904, 1906. In this embodiment, the congestion risk value calculation unit 58 calculates the congestion risk value of the avoidance route 1912 based on the logical sum of the multiple collision risk values excluding the maximum collision risk value from among the multiple collision risk values.

[0154] The collision risk assessment unit 55 determines whether the ship 200 should deviate from the avoidance route 1912 or continue on the avoidance route 1912 based on the congestion risk value of the avoidance route 1912. The route planning system 1 repeats collision avoidance processing with multiple obstacles 1904, 1906 along the planned route through which the ship 200 will pass, i.e., the planned route 202 or the avoidance route 1912, and if there is a high risk of collision on the planned route, recalculate and reset the avoidance route.

[0155] 24 is a block diagram showing a route planning system 1 for safely navigating a moving body (own ship) according to another embodiment of the route planning system of the present invention. The route planning system 1 comprises a route planning unit 2, a GNSS 3, one or more sensor units 4, a processing circuit 5, a navigation control unit 6, and a display unit 7. The route planning unit 2, the GNSS 3, and the one or more sensor units 4 function in the same way as those shown in FIG.

[0156] The processing circuit 5 includes a route planning information acquisition unit 51, a moving body information acquisition unit 52, an obstacle information acquisition unit 53, a collision risk value calculation unit 54, a collision risk assessment unit 55, an avoidance route generation unit 56, a direction setting unit 57, and a maximum collision risk comparison unit 60. The route planning information acquisition unit 51, the moving body information acquisition unit 52, the obstacle information acquisition unit 53, the collision risk value calculation unit 54, the collision risk assessment unit 55, the avoidance route setting unit 56, and the direction setting unit 57 each function in the same way as those shown in FIG.

[0157] The route planning system 1 is equipped with a maximum collision risk comparison unit 60, and the collision risk value is input from the collision risk value calculation unit 55 to the maximum collision risk comparison unit 60. The maximum collision risk comparison unit 60 calculates and compares the maximum collision risk values of the planned route and the avoidance route.

[0158] The maximum collision risk comparison unit 60 calculates the maximum risk value of the planned route and the maximum risk value of the avoidance route, and compares the maximum risk value of the planned route 202 with the maximum risk value of the avoidance route. In this embodiment, the maximum collision risk value of another ship 1906 when the own ship 200 navigates the avoidance route is higher than that of another ship 1904 when the own ship 200 navigates the planned route 202. As described above, the comparison result is output to the collision risk evaluation unit 55.

[0159] Figure 25 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) according to another embodiment of the route planning system of the present invention. The difference between the configuration of the route planning system 1 shown in Figure 23 and the configuration of the embodiment shown in Figure 22 is that the processing circuit 5 of the former is equipped with a distance calculation unit 61. The distance calculation unit 61 acquires route information from the navigation planned route information acquisition unit 51 and the avoidance route setting unit 56, and calculates the distances of the planned route and the avoidance route from the avoidance starting point.

[0160] The distance from the start point of the avoidance route may be calculated as the distance traveled by the ship 200 when a predetermined time has elapsed since the start of the avoidance route, for each planned route and each avoidance route. The position of the start point of the avoidance route may be the current location of the ship 200, or it may be assumed to be on a route that has not yet been navigated on the planned route. The calculation of the distance of the avoidance route may be performed after the avoidance route has been selected to check whether the distance of the avoidance route is significantly longer than the planned route. This may also be taken into consideration as one of the selection factors when selecting a planned route from potential planned route patterns.

[0161] Furthermore, when generating potential avoidance route patterns, a limit on the distance of the avoidance route may be set in advance. In this case, if the potential avoidance route patterns do not contain an appropriate avoidance route whose collision risk value is below the threshold, the distance condition may be relaxed and the route may be reset.

[0162] As described above, the distance calculation result is output to the collision risk assessment unit 55, and together with the comparison result between the planned route and the maximum collision risk of each avoidance route output from the maximum collision risk comparison unit 60, a determination is made as to whether or not a change in navigation route is necessary.

[0163] Figure 26 is a diagram showing the relationship between the maximum collision risk when a ship navigates a planned route and the maximum collision risk when it navigates an avoidance route in another embodiment of the route planning system of the present invention, and shows that the maximum collision risk is within the second-largest range from a predetermined base.

[0164] In contrast to Figure 26, Figure 27 is also a diagram showing the relationship between the maximum collision risk when a ship navigates a planned route and the maximum collision risk when it navigates an avoidance route in another embodiment of the route planning system of the present invention, and shows that the maximum collision risk is outside the second-largest range from a specified base.

[0165] Figure 26 shows the position of a diagram showing the relationship between the maximum collision risk when a vessel navigates a planned route and the maximum collision risk when navigating an avoidance route within a predetermined reference range, in one embodiment, while Figure 27 shows that the position is outside the predetermined reference range. That is, the gray shaded area in the diagram is an example of the predetermined reference range, and indicates that the relationship between the maximum collision risk when navigating the planned route and the maximum collision risk when navigating an avoidance route, shown by the black circle, is within the predetermined reference range.

[0166] This standard range indicates that the maximum collision risk of the avoidance route (1) set on the planned route is sufficiently low, and indicates that even if the difference between the congestion risk (described below) and the distance between the planned route and the avoidance route (1) is large, it is better to change to the avoidance route (1) as long as it is within the standard range in order to ensure higher safety.

[0167] On the other hand, in Figure 27, the black circle showing the relationship between the maximum collision risk value of the planned route and the maximum collision risk value of the avoidance route (2) is in the lower right area of the figure, that is, a position where the risk is reduced, but it is not within the standard range. In other words, although the maximum collision risk value may be reduced by changing to the avoidance route (2), it cannot be expected to be reduced as greatly as with the avoidance route (1).

[0168] In this case, it may be decided not to change course to the avoidance route (2), but the necessity of doing so may be further considered. In the example of the position shown in Figure 25, the distance between the start point and end point of the avoidance route is calculated, and this is also added to the factors for making the decision. Although the risk reduction effect of changing course to the avoidance route (2) is not great, it has the advantage of allowing the ship to return to the planned route early.

[0169] Figure 28 is a block diagram showing a route planning system for safely navigating a moving body (own ship) according to another embodiment of the route planning system of the present invention. In this embodiment, the processing circuit 5 is provided with a congestion risk value calculation unit 58 and a congestion risk comparison unit 62, and the comparison result regarding the congestion risk is input to the collision risk evaluation unit 55 and used to determine whether or not collision avoidance is necessary, which is a difference from the embodiment shown in Figure 24.

[0170] The congestion risk value calculation unit 58 is connected to the collision risk value calculation unit 54 and is configured to communicate with the collision risk value calculation unit 54 to receive multiple collision risks for multiple obstacles (other ships) 1704 and other obstacles (other ships) 1706-1712 along the planned route 202 shown in Figure 17.

[0171] The congestion risk value calculation unit 58 calculates a congestion risk value related to the planned route 202 along the current route direction based on multiple collision risks. As already explained, the congestion risk value indicates the degree of simultaneous approach of obstacles included in the congestion risk area, calculated based on the collision risk corresponding to each obstacle included in the area where multiple obstacles are congested.

[0172] The congestion risk value calculation unit 58 calculates the congestion risk corresponding to the planned route 202 based on the value of the logical sum of the collision risk values as calculation examples corresponding to the plurality of obstacles 1704 and obstacles 1706-1712. In this embodiment, the congestion risk value calculation unit 58 calculates the congestion risk value of the planned route 202 based on the value of the logical sum of the plurality of collision risk values excluding the maximum collision risk value among the plurality of collision risk values, i.e., the collision risk value for the obstacle 1704.

[0173] As already explained, the "logical OR" here refers to a logical OR based on logic that is true when one or both of two propositions in a logical operation are true and false when both are false, that is, a logical OR in which the output of a logical circuit or binary value is 1 when one or both of the two inputs is 1 and 0 when both are 0. For example, if there are four obstacles Obs(1), Obs(2), Obs(3), and Obs(4), and the collision risks are 0.3, 0.5, 0.7, and 0.9, respectively, the maximum collision risk is Obs(4), which is 0.9, and the logical OR of the other three obstacles Obs(1) to Obs(3), is 0.7.

[0174] On the other hand, for obstacles other than those with the maximum collision risk value, a collision risk value according to the degree of simultaneous approach, i.e., a congestion risk value, is evaluated. Therefore, for obstacles with collision risk values other than the maximum collision risk value, the collision risk value is input by the congestion risk value calculation unit 58 to calculate the congestion risk value.

[0175] In one embodiment, the collision risk value associated with the obstacle with the highest collision risk may be individually evaluated and excluded. When calculating the congestion risk value excluding the obstacle with the highest collision risk value, the congestion risk value is calculated appropriately including the obstacle with the next highest maximum risk value after the highest collision risk value.

[0176] When evaluating the collision risk value, the congestion risk value is calculated based on the collision risk values of one or more obstacles excluding the obstacle with the maximum collision risk value, and the maximum collision risk value and the congestion risk value are evaluated separately. This is because in this embodiment, priority is given to setting an avoidance plan that takes the obstacle with the maximum collision risk value into consideration.

[0177] When performing collision avoidance, other collision risk values may be taken into consideration, such as a collision risk value with an obstacle including an obstacle having the second highest collision risk value after the maximum collision risk value. The configuration shown in FIG. 28 follows this configuration, and also takes congestion risk into consideration. Note that, when calculating the congestion risk value, the collision risk value with the obstacle having the maximum collision risk value may be excluded, and obstacles having the second highest or higher collision risk values may be selected to calculate the congestion risk value, or the congestion risk value may be calculated including the obstacle having the maximum collision risk value.

[0178] Figure 29 is a block diagram showing a route planning system for safely navigating a moving body (or own ship) 200, according to another embodiment of the route planning system of the present invention. In the embodiment of the route planning system of the present invention shown in Figure 29, the processing circuit 5 is equipped with the distance calculation unit 61 provided in the embodiment shown in Figure 25, and the congestion risk value calculation unit 58 and congestion risk comparison unit 62 provided in the embodiment shown in Figure 28. The collision risk assessment unit 55 combines the comparison results of the maximum risk value comparison unit 60 shown at the beginning, the comparison results of the congestion risk comparison unit 62, and the distance difference between the planned route and the avoidance route calculated by the distance calculation unit 61 to determine a change to the avoidance route.

[0179] Figure 30 is a diagram showing the relationship between the congestion risk when navigating a planned route and the congestion risk when navigating an avoidance route in another embodiment of the route planning system of the present invention. In this embodiment, Figure 30 shows the relationship between the congestion risk when the ship 200 navigates a planned route and the congestion risk when the ship 200 navigates an avoidance route, and as with the maximum collision risk, the relationship is divided into three relationships, 1 to 3, depending on the magnitude of the values of both.

[0180] Therefore, the route planning system 100 of the present invention enables the ship operator to navigate the ship 200 more safely by avoiding collisions with multiple surrounding obstacles such as other ships and terrain on the planned route (planned route 202 or avoidance route 212) displayed on the screen of the display unit 7 and the generated avoidance route (avoidance route 212 or other avoidance route).

[0181] 31A, 31B, and 31C are flowcharts illustrating a method 3100 for planning a navigation route according to one embodiment of the route planning system of the present invention.

[0182] In step 3102, the planned route information acquisition unit 51 acquires the planned route 202 indicating the planned navigation route of the ship 200. In step 3104, the moving body information acquisition unit 52 acquires moving body information including the position, moving direction, and speed of the ship 200. In step 3106, the obstacle information acquisition unit 53 acquires obstacle information including the position, moving direction, and speed of each obstacle from multiple obstacles located in the surrounding area of the ship 200. In step 3108, the collision risk value calculation unit 54 calculates a collision risk value indicating the risk of collision between the ship 200 and the multiple obstacles based on the moving body information and obstacle information.

[0183] In step 3110, the collision risk assessment unit 55 determines whether or not avoidance is necessary based on a comparison between the collision risk value and a threshold. If the collision risk value when navigating the planned route 202, or the collision risk value when navigating a previously set avoidance route, is below the collision risk threshold, it is determined that avoidance is not necessary, and navigation continues as is. Note that, because the situation around the own ship 200 changes from moment to moment, as already explained, the own ship 200 and the surrounding situation are grasped at predetermined intervals, and the collision risk value is calculated and evaluated repeatedly to confirm safety.

[0184] On the other hand, if it is determined in step 3110 that a collision avoidance route is necessary, an avoidance route is set based on the flow shown in Figure 31B. In step 3114, an avoidance start point on the untraveled planned route, an avoidance end point deviating from the planned route, and the bearing at the end point (end point bearing) are set. In step 3116, one or more potential collision avoidance route patterns are generated as candidate collision avoidance routes by connecting the collision avoidance start point and the avoidance end point.

[0185] Next, in step 3118, a collision risk value is calculated for each of the generated potential collision avoidance route patterns when the moving object navigates. In step 3120, the maximum collision risk value for each of the one or more obstacles targeted by each potential collision avoidance route pattern is extracted. Then, in step 3122, an avoidance route is selected based on the maximum collision risk value for each potential collision avoidance route pattern.

[0186] In step 3124, the selected avoidance route is judged and evaluated to determine whether the collision risk value is below the collision risk threshold, and it is confirmed whether there is any problem in navigating the avoidance route. If it is determined that there is no collision risk, the ship 200 navigates the selected avoidance route (step 3126).

[0187] On the other hand, if the collision risk value of any of the potential avoidance route patterns is not below the sudden risk threshold, it means that none of these avoidance routes can sufficiently avoid the collision risk, so the end point position is changed again to generate potential avoidance route patterns and repeat the same evaluation and judgment.For example, it is possible to generate a pattern that is more detour-oriented, even if it increases the length (distance) of the avoidance route.

[0188] Since the setting of the direction at the end point of the avoidance and the selection of the avoidance route have already been explained, detailed explanations will be omitted here.

[0189] Figure 31C shows a flow when setting an avoidance route taking into consideration congestion risk in addition to collision risk. The processing is the same as that in Figure 31B up to step 3124. Here, in step 3128, a congestion risk value is also calculated for the selected avoidance route, and in step 3130, the final avoidance route is selected taking both the collision risk value and the congestion risk value into consideration. The process for selecting an avoidance route here has already been explained, so a detailed explanation will be omitted.

[0190] The route planning system 100 detects ships that are recognized as obstacles, bad sea conditions, bad weather, The navigation control unit 5 controls the ship 200 to navigate along the planned route 202 while receiving support from the route planning system 100 and referring to a display 6 that is appropriately equipped on the ship or incorporated in the route planning system 100.

[0191] Figure 31D shows the flow of an embodiment in which potential avoidance route patterns are generated taking into account the route length of the avoidance route, and an avoidance route is selected based on the maximum collision risk value already explained. The difference from Figure 31B is that in this embodiment, the allowable route length of the allowable avoidance route is first set (step 3128), an avoidance end point and an avoidance route are generated so as to satisfy this range, and the maximum collision risk value is calculated and evaluated before selecting one or more avoidance routes.

[0192] That is, one potential avoidance route pattern that minimizes the maximum collision risk value may be selected as the avoidance route. Alternatively, multiple potential avoidance route patterns that have maximum collision risk values below a predetermined threshold may be selected, and the final avoidance route may be selected from these, taking into account the length of the avoidance route (step 3126). The selection here may be made in advance by formulating a rule regarding the relationship between the maximum collision risk value and the avoidance distance, and the pattern may be determined according to this rule, or the user may select a pattern each time, taking the situation into consideration.

[0193] If none of the potential avoidance route patterns based on the set avoidance route length falls below the maximum collision risk threshold, it means that no possible avoidance route can be found. In this case, the allowable avoidance route length is gradually extended (step 3130), and potential avoidance route patterns are generated again to select an avoidance route.

[0194] Here, a method for gradually increasing the allowable length of the avoidance route has been shown, but it is also possible to first generate many potential avoidance route patterns connecting the start point and end point of the avoidance route, select a potential avoidance route pattern that is below the maximum collision risk threshold, calculate the avoidance route length for each pattern, and select the optimal avoidance route based on the maximum collision risk value and the avoidance route length (not shown).

[0195] Furthermore, in the above embodiment, only the maximum collision risk value and the length of the avoidance route were used as factors in selecting the avoidance route, but the congestion risk value already explained may also be used as a selection factor, and the optimal avoidance route may be selected based on three factors (not shown).

[0196] The above is a description of an embodiment of the route planning system and route planning method of the present invention. The various exemplary logical steps and units described in connection with the embodiments of the invention shown herein may be implemented or executed by a machine such as a processor.

[0197] A processor may be a microprocessor, but may also be a controller, microcontroller, state machine, or combination thereof. A processor may include electrical circuitry configured to process computer-executable instructions. In alternative embodiments, a processor includes an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable device that performs logical operations without processing computer-executable instructions. A processor may also be implemented as a combination of computing devices, such as, for example, a combination of a digital signal processor (DSP) and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or other such configuration.

[0198] Although primarily digital technology applications are envisioned herein, the processor may also include analog components. For example, some or all of the signal processing algorithms described herein may be implemented using analog circuitry or mixed analog and digital circuitry. The computing environment may include any type of computer system, including, but not limited to, a microprocessor, mainframe computer, digital signal processor, portable computing device, device controller, or computer system based on a computing engine within a device. [Explanation of symbols]

[0199] 1 Route planning system 2 Route Planning Department 3 GNSS receivers 4. One or more sensor units 5 Processing circuit 6 Navigation Control Unit 7 Display section 51 Planned route information acquisition unit 52 Mobile object (own ship) information acquisition section 53 Obstacle information acquisition unit 54 Collision risk value calculation unit 55 Collision Risk Assessment Section 56 Collision avoidance route setting section 57 Direction setting section 58 Congestion risk value calculation unit 59 Maximum collision risk selection section 60 Maximum collision risk comparison section 61 Distance calculation unit 62 Congestion Risk Comparison Section 552 Maximum Collision Risk Assessment Section 554 Congestion Risk Assessment Department 562 Potential Evasion Route Pattern Generation Unit 564 Route Pattern Evaluation Unit 566 Collision Avoidance Route Selection Department 200 Mobile 202 Planned Route 204 Obstacles 210 Avoidance starting point 212 Avoidance Route

Claims

1. A route planning system that plans a route to a destination for a moving body moving on water, a planned route information acquisition unit that acquires planned route information indicating a planned route of the moving object; a mobile object information acquisition unit that acquires mobile object information including a position, a moving direction, and a speed of the mobile object; an obstacle information acquisition unit that acquires obstacle information including the position, moving direction, and speed of one or more obstacles around the moving object; a collision risk value calculation unit that calculates a collision risk value indicating a risk of collision between the moving object and the obstacle based on the moving object information and the obstacle information; an avoidance route setting unit that determines whether the moving body needs to avoid collisions based on the collision risk value, and if it determines that avoidance is necessary, sets an avoidance route that deviates from the planned route and whose end point bearing is a predetermined end point bearing; A route planning system comprising:

2. 2. The route planning system according to claim 1, The end point direction is a direction that coincides with the moving direction of the moving body at an avoidance start position where the moving body starts avoidance from the planned route, A route planning system.

3. 2. The route planning system according to claim 1, The end point direction is a direction that corresponds to the direction at a selected position on the planned route that the moving body has not yet navigated, A route planning system.

4. 2. The route planning method according to claim 1, The end point direction is a direction that corresponds to the direction from the avoidance start position where the moving body starts avoidance from the planned route toward the destination, A route planning system.

5. 2. The route planning method according to claim 1, The end point direction is a direction that corresponds to a direction toward a selected position on the unnavigated route of the moving body on the planned route, A route planning system.

6. A route planning system according to any one of claims 1 to 5, The collision avoidance route setting section an avoidance route pattern generation unit that generates one or more potential avoidance route patterns between the avoidance start position and the avoidance end point; an avoidance route selection unit that selects an avoidance route from the one or more potential avoidance route patterns based on the collision risk value for each of the one or more potential avoidance route patterns calculated by the collision risk value calculation unit; A route planning system comprising:

7. 7. The route planning system according to claim 6, A route planning system that selects, as the avoidance route, a potential avoidance route pattern that has the smallest collision risk value.

8. 7. The route planning system according to claim 6, further comprising: an avoidance route distance calculation unit that calculates an avoidance distance between the avoidance start point and the avoidance end point when the moving object navigates along the one or more potential avoidance route patterns, the avoidance route selection unit selects the avoidance route from the one or more potential avoidance route patterns based on the collision risk value and the avoidance distance of the one or more potential avoidance route patterns. Route planning system.

9. 9. The route planning system according to claim 8, The avoidance route setting unit extracting a maximum collision risk obstacle corresponding to a maximum collision risk value from the obstacles that would be an impediment when the mobile body navigates the one or more potential collision avoidance route patterns; Select a potential avoidance route pattern in which the maximum collision risk value of the maximum collision risk obstacle is equal to or less than a predetermined collision risk threshold; selecting the collision avoidance route from the selected potential collision avoidance route patterns based on the collision risk value and the collision avoidance distance; Route planning system.

10. The route planning system according to any one of claims 1 to 5, further comprising: a congestion risk value calculation unit that calculates a congestion risk value indicating a degree of simultaneous approach to the plurality of obstacles based on a collision risk value between the moving body and each of the plurality of obstacles; the collision avoidance route setting unit determines whether the moving body needs to take avoidance based on the congestion risk value in addition to the collision risk value, and sets the collision avoidance route when the collision avoidance necessity determination unit determines the need for collision avoidance. Route planning system.

11. 11. The route planning system according to claim 10, the congestion risk value calculation unit calculates the congestion risk value based on a logical sum of collision risk values corresponding to the plurality of obstacles, Route planning system.

12. 12. The route planning system according to claim 11, The congestion risk value calculation unit excluding a maximum collision risk value of a maximum collision risk obstacle corresponding to a maximum collision risk value from the obstacles that will be an obstacle when the mobile body navigates the one or more potential collision avoidance route patterns, and calculating the congestion risk value based on the plurality of collision risk values that includes a second largest collision risk value among the plurality of collision risk values; Route planning system.

13. 11. The route planning system according to claim 10, The avoidance route setting section an avoidance route pattern generation unit that generates one or more potential avoidance route patterns between the avoidance start position and the avoidance end point; an avoidance route selection unit that selects an avoidance route from the one or more potential avoidance route patterns based on the collision risk value and the congestion risk value of the one or more potential avoidance route patterns calculated by the collision risk value calculation unit; A route planning system comprising:

14. 14. The route planning system according to claim 13, The avoidance route setting unit extracting a maximum collision risk obstacle corresponding to a maximum collision risk value from the obstacles that would be an impediment when the mobile body navigates the one or more potential collision avoidance route patterns; Select a potential avoidance route pattern in which the maximum collision risk value of the maximum collision risk obstacle is equal to or less than a predetermined collision risk threshold; selecting one or more potential avoidance route patterns for which the collision risk value is equal to or less than a predetermined threshold value from the one or more selected potential avoidance route patterns; selecting a potential collision avoidance route pattern from the one or more selected potential collision avoidance route patterns based on the collision risk value and the congestion risk value; Route planning system.

15. 15. The route planning system of claim 14, further comprising: an avoidance route distance calculation unit that calculates an avoidance distance between the avoidance start point and the avoidance end point when the moving object navigates along the one or more potential avoidance route patterns, the avoidance route selection unit selects the avoidance route from the one or more potential avoidance route patterns based on the collision risk value, the congestion risk value, and the avoidance distance of the one or more potential avoidance route patterns. Route planning system.

16. 16. The route planning system of claim 15, The avoidance route setting unit When the collision risk value is equal to or less than the collision risk threshold and there is no avoidance route in which the congestion risk value is equal to or less than a predetermined congestion risk threshold, changing the restriction on the end point heading; setting a new avoidance route such that the collision risk value is equal to or less than the collision risk threshold and the congestion risk value is equal to or less than the congestion risk threshold; Route planning system.

17. 16. The route planning system of claim 15, The avoidance route setting unit selecting the one or more potential avoidance route patterns for which the collision risk value is equal to or less than the collision risk threshold and the congestion risk value is equal to or less than the congestion risk threshold; selecting the potential collision avoidance route pattern that minimizes the collision avoidance distance as the collision avoidance route; Route planning system.

18. 2. The route planning system according to claim 1, the mobile object information acquisition unit acquires mobile object information including a position, a moving direction, and a speed of the mobile object at a predetermined period; the obstacle information acquisition unit acquires obstacle information including positions, moving directions, and speeds of one or more obstacles around the moving object at a predetermined period; the collision risk value calculation unit calculates a collision risk value indicating a risk of collision between the moving body and the obstacle at a predetermined period based on the moving body information and the obstacle information; the avoidance route setting unit determines whether the moving body needs to avoid collision based on the collision risk value at a predetermined period, and sets the avoidance route when it determines that avoidance is necessary. Route planning system.

19. A route planning method for planning a route to a destination of a moving body moving on water, comprising: Acquire planned route information indicating a planned route of the moving object; Acquire moving object information including the position, moving direction, and speed of the moving object; Obtaining obstacle information including the position, moving direction, and speed of one or more obstacles around the moving object; calculating a collision risk value indicating a risk of collision between the moving body and the obstacle based on the moving body information and the obstacle information; determining whether or not the moving body needs to take action based on the collision risk value, and if it is determined that action is necessary, setting an action route that deviates from the planned route and the direction of the action route end point of which is a predetermined end point direction; Route planning methods.

20. 20. The route planning method according to claim 19, The end point orientation is a direction that coincides with the moving direction of the moving body at an avoidance start position where the moving body starts avoidance from the planned route; a heading that matches the direction of the moving body at a selected position on the planned route that has not yet been navigated; A direction that matches the direction from the avoidance start position where the moving body starts avoiding the planned route towards the destination, or a direction that corresponds to a direction toward a selected position among unnavigated routes of the moving body on the planned route; A route planning method that is either

21. The route planning method according to claim 20, further comprising: generating one or more potential collision avoidance route patterns between the collision avoidance start position and the collision avoidance end point; selecting an avoidance route from the one or more potential avoidance route patterns based on the calculated collision risk value for each of the one or more potential avoidance route patterns; Route planning methods.

22. The route planning method according to claim 21, further comprising: calculating an avoidance distance between the avoidance start point and the avoidance end point when the moving object navigates along the one or more potential avoidance route patterns; selecting the avoidance route from the one or more potential avoidance route patterns based on the collision risk value and the avoidance distance of the one or more potential avoidance route patterns; Route planning methods.

23. 23. The route planning method according to claim 22, further comprising: calculating a congestion risk value indicating a degree of simultaneous approach to the plurality of obstacles based on a collision risk value between the moving body and each of the plurality of obstacles; determining whether the moving body needs to take action based on the congestion risk value in addition to the collision risk value, and setting the action route when the action-avoidance necessity determination unit determines that action-avoidance is necessary; Route planning methods.

24. 24. The route planning method according to claim 23, further comprising: calculating an avoidance distance between the avoidance start point and the avoidance end point when the moving object navigates along the one or more potential avoidance route patterns; selecting the avoidance route from the one or more potential avoidance route patterns based on the collision risk value, the congestion risk value, and the avoidance distance of the one or more potential avoidance route patterns; Route planning methods.

25. A computer program product that, when executed on a computer, causes the computer to execute executable instructions: Acquire planned route information indicating a planned route of the moving object; acquiring moving object information including the position, moving direction, and speed of the moving object; Obtaining obstacle information including the position, moving direction, and speed of one or more obstacles in the vicinity of the moving object; calculating a collision risk value indicating a risk of collision between the moving body and the obstacle based on the moving body information and the obstacle information; determining whether or not the moving body needs to take action based on the collision risk value, and if it is determined that action is necessary, setting an action route that deviates from the planned route and the direction of the action route end point of which is a predetermined end point direction; Computer program.

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