Navigation device

Abstract

To provide a navigation device which can guide a route so as to be low in a cost.SOLUTION: A communication part 8 of a navigation device 1 acquires passage success / failure information (r) associated with a passage parameter indicating a condition at passage, and a control part 2 calculates a passage success rate for predicting a success or a failure in passage of a traffic circle on the basis of the passage success / failure information (r) and the passage parameter during the passage, and also calculates a passage cost on the basis of the passage success rate. A route whose cost becomes the lowest is selected out of routes from a current position up to a destination, and a vehicle is guided by creating a route up to the destination so as to include the route, and a route guide is performed so as to be low in a cost.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a navigation device that calculates a passing cost when a vehicle passes through a roundabout. [Background technology]

[0002] Conventionally, when a bypass road is provided at a roundabout, a navigation device has been proposed that guides a vehicle onto the bypass road to avoid the roundabout (see, for example, Patent Document 1). The conventional navigation device described in Patent Document 1 is configured to improve convenience for the user by guiding the vehicle onto the bypass road. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-101919 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the navigation device of Patent Document 1, when the roundabout has a simple configuration or when the bypass route is a large detour to the destination, guiding the vehicle to the bypass route can increase costs. In other words, there are cases where the cost of a route that goes through the roundabout is high, and cases where the cost of a route that avoids the roundabout is high, and conventional navigation devices have not been able to guide the user to a route that is low cost.

[0005] Therefore, an object of the present invention is to provide a navigation device that can provide route guidance at low cost. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the navigation device of the present invention described in claim 1 comprises a route search unit that searches for multiple routes to the destination of a target mobile body; a success rate calculation unit that, when a first route of the multiple routes passes through a first roundabout, calculates the success rate of passing through the first roundabout based on passing condition information indicating the structural characteristics of the first roundabout and the environmental characteristics at the time of passing, and coefficient information; and a cost calculation unit that calculates the cost of passing through the first roundabout based on the route portion of the first route at the first roundabout and the passing success rate, wherein the coefficient information is generated based on case data including past passing success information when multiple mobile bodies have passed through multiple roundabouts in the past, and past passing condition information indicating the structural characteristics of each roundabout and the past environmental characteristics when each mobile body passed through each roundabout. Another navigation device is characterized by comprising an acquisition unit that acquires passage success / failure information indicating whether a mobile body has successfully passed through a roundabout and passage parameters indicating the conditions when the mobile body passes through the roundabout, a success rate calculation unit that calculates a passage success rate that predicts whether the mobile body will successfully pass through the roundabout based on the passage success / failure information and the passage parameters, a route search unit that searches for a route to guide the mobile body, and a cost calculation unit that calculates the passage cost incurred at the roundabout that the mobile body is about to pass based on the route and the passage success rate.

[0007] The navigation method of the present invention described in claim 6 comprises a route search process for searching for multiple routes to the destination of a target mobile body; a success rate calculation process for calculating, when a first route among the multiple routes passes through a first roundabout, the success rate of passing through the first roundabout based on passing condition information indicating the structural characteristics of the first roundabout and the environmental characteristics at the time of passing, and coefficient information; and a cost calculation process for calculating the cost of passing through the first roundabout based on the route portion of the first route at the first roundabout and the passing success rate, wherein the coefficient information is generated based on case data including past passing success information when multiple mobile bodies have passed through multiple roundabouts in the past, and past passing condition information indicating the structural characteristics of each roundabout and the past environmental characteristics when each mobile body passed through each roundabout. Another navigation method is characterized by including an acquisition step of acquiring passage success / failure information indicating whether a mobile body has successfully passed through a roundabout and passage parameters indicating the conditions when the mobile body passes through the roundabout; a success rate calculation step of calculating a passage success rate that predicts whether the mobile body will successfully pass through the roundabout based on the passage success / failure information and the passage parameters; a route search step of searching for a route to guide the mobile body; and a cost calculation step of calculating a passage cost incurred at the roundabout through which the mobile body is to pass based on the route and the passage success rate. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an outline of a navigation device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram showing a state in which a vehicle equipped with the navigation device passes through a roundabout; [Figure 3] 6 is a flowchart showing an example of a procedure for an information acquisition process executed by a server connected to the navigation device. [Figure 4] 4 is a flowchart showing an example of a procedure for a route creation process executed by the navigation device. [Figure 5] 2 is a schematic diagram showing a route along which a vehicle equipped with the navigation device is guided; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below. A navigation device according to an embodiment of the present invention includes an acquisition unit that acquires passage success / failure information indicating whether a mobile object has successfully passed through a roundabout and passage parameters indicating conditions when the mobile object passes through the roundabout, a success rate calculation unit that calculates a passage success rate for predicting whether the mobile object will successfully pass through the roundabout based on the passage success / failure information and the passage parameters, a route search unit that searches for a route along which the mobile object should be guided, and a cost calculation unit that calculates a passage cost incurred at the roundabout through which the mobile object is to pass based on the route and the passage success rate.

[0010] According to the navigation device of this embodiment, the passing success rate at a roundabout is calculated based on the passing success rate and the passing parameters, and the passing cost is calculated based on the passing success rate, thereby enabling route guidance to be provided at low cost. In this case, it is preferable that past passing success rate information and the passing parameters at that time are stored in association with each other, and the passing success rate is calculated based on the past passing success rate information and the passing parameters and the passing parameters at the time of attempting to pass.

[0011] In addition, the success rate calculation unit may calculate the passage success rate based on passage success / failure information specific to the roundabout that the mobile body is attempting to pass through, or may calculate the passage success rate based on passage success / failure information at multiple roundabouts.

[0012] The passage success / failure information is preferably determined as a success when the mobile body passes the guided exit without going around the roundabout when the mobile body is receiving route guidance, and is determined as a success when the mobile body passes the exit without going around the roundabout when the mobile body is not receiving route guidance.Therefore, when the mobile body is receiving route guidance and passes an exit other than the guided exit, that is, when the mobile body passes the guided exit or exits the roundabout through an exit earlier than the guided exit, the passage success / failure information can be determined as a failure.Furthermore, the passage success / failure information can be determined as a failure when the mobile body goes around the roundabout more than once.

[0013] The passage parameters preferably include at least one of the number of exits, the diameter, the presence or absence of a central island, the number of lanes, and the number of stacked floors in a roundabout. Therefore, when there are many exits, many lanes, or many floors, the roundabout structure is complex and it is thought that mobile objects are more likely to fail to pass through. By using information that likely influences whether or not a roundabout passes as a passage parameter, the accuracy of calculating the passage success rate can be improved. Furthermore, when there is no central island, it is difficult to tell that the roundabout is a roundabout, and the part guiding the inner periphery of the circular route is unclear, so it is thought that passing through is more likely to fail. By using information that likely influences whether or not a roundabout passes as a passage parameter, the accuracy of calculating the passage success rate can be improved.

[0014] The passage parameters preferably include at least one of the following when a mobile object passes through a roundabout: weather, time of day, the number of times the same mobile object or driver has passed through the roundabout in the past, the number of exits to be passed, and whether route guidance is in progress. As a result, it is considered that a mobile object is more likely to fail to pass through a roundabout if it is raining or cloudy, if it is a time of day after sunset, if there are many exits to be passed, or if the same mobile object or the same driver has passed through the roundabout only a few times in the past. By using such information that is likely to affect the success or failure of passage as passage parameters, the calculation accuracy of the passage success rate can be improved.

[0015] The cost calculation unit preferably calculates the passage cost based on at least one of the distance from the entrance where the mobile body enters the roundabout to the guided exit and the angle between the direction in which the entrance extends and the direction in which the exit extends, thereby enabling the cost calculation unit to accurately calculate the cost for the mobile body to reach the guided exit after entering the roundabout, thereby improving the accuracy of calculation of the passage cost.

[0016] Furthermore, a navigation method according to an embodiment of the present invention includes an acquisition step of acquiring passage success / failure information indicating whether a mobile object has successfully passed through a roundabout and passage parameters indicating conditions when the mobile object passes through the roundabout, a success rate calculation step of calculating a passage success rate that predicts whether the mobile object will successfully pass through the roundabout based on the passage success / failure information and the passage parameters, a route search step of searching for a route to guide the mobile object, and a cost calculation step of calculating a passage cost incurred at the roundabout through which the mobile object is to pass based on the route and the passage success rate. According to the navigation method of this embodiment, route guidance can be provided at low cost, similar to the above-described navigation device.

[0017] The above-described navigation method may also be implemented as a navigation program that is executed by a computer, thereby enabling route guidance to be provided at low cost using a computer.

[0018] The above-described navigation program may be stored on a computer-readable recording medium, which allows the program to be distributed as a standalone program rather than being incorporated into a device, and allows for easy version upgrades. [Example]

[0019] Hereinafter, an embodiment of the present invention will be specifically described. Fig. 1 is a block diagram showing an outline of a navigation device, Fig. 2 is a schematic diagram showing a state in which a vehicle equipped with the navigation device passes through a roundabout, Fig. 3 is a flowchart showing an example of the procedure of an information acquisition process executed by a server connected to the navigation device, Fig. 4 is a flowchart showing an example of the procedure of a route creation process executed by the navigation device, and Fig. 5 is a schematic diagram showing a route along which a vehicle equipped with the navigation device is guided.

[0020] The navigation device 1 is mounted on a vehicle as a moving body to provide route guidance, and as shown in FIG. 1, includes a control unit 2, a GPS receiving unit 3, a storage device 4, an operation unit 5, a display unit 6, an audio output unit 7, and a communication unit 8.

[0021] The control unit 2 is composed of a CPU (Central Processing Unit) equipped with memories such as RAM (Random Access Memory) and ROM (Read Only Memory), and is responsible for overall control of the navigation device 1. The control unit 2 also functions as a route search unit that searches for a route to guide the vehicle from the current position to the destination, and as a guidance unit that guides the vehicle. Furthermore, the control unit 2 also functions as a success rate calculation unit that calculates a passing success rate, as will be described later, and as a cost calculation unit that calculates a passing cost, a passing arrival cost, and a non-passing arrival cost.

[0022] As is well known, the GPS receiver 3 receives radio waves transmitted from a plurality of GPS (Global Positioning System) satellites, obtains current position information (current location information), and outputs the information to the control unit 2. Note that, although this embodiment shows an example in which the GPS receiver 3 is provided integrally with the navigation device 1, the GPS receiver 3 may be configured as a separate unit and may be detachable from the navigation device 1.

[0023] The storage device 4 is composed of, for example, a hard disk or non-volatile memory, and stores map data for route search and display on the display unit 6, programs and data for the control unit 2 to control the navigation device 1, and part wear information, which will be described later, and is read and written under the control of the control unit 2.

[0024] The operation unit 5 is composed of input means such as buttons and a touch panel, and voice input means such as a microphone. The operation unit 5 performs various input operations for the navigation device 1, and outputs control signals indicating the input operations to the control unit 2.

[0025] The display unit 6 is composed of a liquid crystal display, a driver circuit that controls the liquid crystal display, etc. Under the control of the control unit 2, the display unit 6 displays map data, various icons, operation buttons, etc., as well as the route to the destination, the direction of travel, etc., on the liquid crystal display.

[0026] The audio output unit 7 is composed of a speaker, an amplifier for driving the speaker, and the like, and outputs audio guidance and confirmation sounds during operation under the control of the control unit 2.

[0027] The communication unit 8 is composed of circuits, antennas, etc. for communicating with networks such as the Internet or public lines. The communication unit 8 communicates with a communication unit SV1 of an external server SV, and acquires pass success / failure information r (described later) from a memory unit SV3 via a control unit SV2, thereby functioning as an acquisition unit.

[0028] The passage success / failure information r is information indicating whether the vehicle has successfully passed through the roundabout. When the vehicle is receiving route guidance, if the vehicle passes through the guided exit without going around the roundabout once, it is stored as a success (r=0), and if the vehicle passes through an exit other than the guided exit or if the vehicle goes around the roundabout more than once, it is stored as a failure (r=1). Furthermore, when the vehicle is not receiving route guidance, the passage success / failure information r is stored as a success (r=0) when the vehicle passes through an arbitrary exit without going around the roundabout once, and it is stored as a failure (r=1) when the vehicle goes around the roundabout more than once. The server SV acquires the passage success / failure information r by communicating with a navigation device installed in a vehicle that has passed through an arbitrary roundabout, and stores it in the memory unit SV3.

[0029] Such passage success / failure information r is stored in association with a plurality of passage parameters that indicate the conditions when a vehicle passes through a roundabout. The passage parameters include both static information determined by the structure of the roundabout and dynamic information that changes depending on the situation when the vehicle passes through. In this embodiment, the passage parameters include, as static information, the number of exits v1, the diameter v2, and the number of lanes (whether there are two or more lanes) v3 at the roundabout, and, as dynamic information, v4 whether route guidance is in progress, v5 the number of exits to be passed, and v6 the number of times the same vehicle has previously passed through the roundabout. If the driver can be distinguished, the number of times the same driver has previously passed through the roundabout may be used instead of the number of times the same vehicle has previously passed through it.

[0030] As a specific example, let us consider the passage parameters for a roundabout RA as shown in FIG. 2, where a vehicle that has passed through the roundabout RA once before is guided to pass through the second exit R2 clockwise from the entrance R0 of the four exits R1 to R4. In this case, v1 is 4 because there are four exits, v2 is 0.4 because the diameter is 40 m (in this embodiment, the unit is 100 m), v3 is 0 because there is one lane within the roundabout RA, v4 is 1 because route guidance is in progress, v5 is 1 because one exit R1 will be passed, and v6 is 1 because the number of times the vehicle has passed through the roundabout once. A six-dimensional feature vector V = (v1, v2, v3, v4, v5, v6) with these six passage parameters as components is stored along with the passage success / failure information r at that time. Note that if there are two or more lanes, v3 is 1, and if route guidance is not in progress, v4 is 0.

[0031] Here, the procedure for the control unit SV2 of the server SV to execute the information acquisition process shown in Fig. 3 will be described. First, the control unit SV2 repeatedly determines whether any vehicle equipped with a navigation device operated by the server SV has entered any roundabout (S100). If any vehicle has entered the roundabout (Y in S100), the control unit SV2 calculates a feature vector V indicating the condition at that time (S110). Next, the control unit SV2 determines whether the vehicle has made one or more laps around the roundabout (S120). If the vehicle has made one or more laps around the roundabout (Y in S120), the control unit SV2 determines that the vehicle has failed to pass and sets the passage success / failure information r to 1 (130). On the other hand, if the vehicle has exited the roundabout before making one lap (N in S120), the control unit SV2 determines whether the vehicle is being guided by the navigation device equipped in the vehicle (S140). If the vehicle is being guided by a navigation device (Y in S140), the control unit SV2 determines whether the exit through which the vehicle passed matches the guided exit (S150). If the vehicle is not being guided by a navigation device (N in S140) and if the exit through which the vehicle passed matches the guided exit (Y in S150), the control unit SV2 determines that the passage was successful and sets the passage success / failure information r to 0 (S160). On the other hand, if the exit through which the vehicle passed does not match the guided exit (N in S150), the control unit SV2 proceeds to S130. After determining the passage success / failure information r in S130 or S160, the control unit SV2 stores the passage success / failure information r and the feature vector V as case data in the memory unit SV3 (S170), and then returns to S100. The information acquisition process is assumed to be always executed when the server SV is operating.

[0032] The information acquisition process may be performed by a navigation device installed in each vehicle, and the passing success / failure information r and the feature vector V may be transmitted to the server SV as case data.

[0033] The following describes in detail how the control unit 2 calculates the passage success rate, which predicts whether or not a vehicle will be able to successfully pass through a roundabout. In this embodiment, the passage failure rate is calculated, and the passage success rate is the value obtained by subtracting the passage failure rate from 1. In other words, calculating the passage failure rate is equivalent to calculating the passage success rate. Alternatively, the passage failure rate may be calculated after calculating the passage success rate using a method similar to that described below.

[0034] Since each passage parameter is considered to have a correlation with the success or failure of passage, if this correlation is quantified into a weight vector W = (w1, w2, w3, w4, w5, w6), the dot product of vector V and vector W becomes an index F of the likelihood of passing failure. By normalizing this index F as P = 1 / {1 + exp(-F)} so that the value range of this index F is between 0 and 1, this P becomes the passing failure rate. Therefore, by calculating the weight vector W based on a combination of the passing success or failure information r accumulated as a case and the feature vector V, and substituting the feature vector Va, which indicates the conditions when attempting to pass, into the formula for the passing failure rate P, it is possible to calculate the passing failure rate Pa, which predicts whether or not a vehicle will fail to pass through the roundabout under those conditions.

[0035] Next, a method for calculating the weight vector W will be described. In this embodiment, the control unit SV1 of the server SV calculates the weight vector W and stores it in the storage unit SV3, and the navigation device 1 acquires the weight vector W from the server SV via the communication unit 8. However, the navigation device 1 may acquire the passage success / failure information r and the feature vector V from the server SV, and the control unit 2 may calculate the weight vector W. The weight vector W is determined so that the value of P calculated from the feature vector V in a past case is close to the passage success / failure information r (1 or 0) indicating whether or not the passage was actually successful at that time. That is, the weight vector W may be determined so that the absolute value of the difference between the passage success / failure information r and the passage failure rate P calculated from the feature vector V for all multiple past cases becomes small (so that the square of the difference becomes small). Therefore, a method of updating the weight vector W using, for example, the steepest descent method can be considered. In the steepest descent method, the passage success / failure information r in the kth case is calculated as k and the failure rate P k The square of the difference between k Next, as shown in the following equation (2), the square of the difference f k Based on this, the weight vector W obtained from the k-1th case k-1 Update W k where α is the learning rate and V k is the feature vector for the kth instance.

[0036]

number

number

[0037] Below, we will explain a specific example of how to calculate the weight vector W using the steepest descent method. First, the pass success / fail information r and each component of the feature vector V for three cases as shown in Table 1 are stored in order, and all components of the initial weight vector W0 are assumed to be 0, and the learning rate α is assumed to be 0.1.

[0038] [Table 1]

[0039] When information about the first case is stored, a weight vector W1 for the first case can be calculated based on the initial weight vector W0, and the pass success / failure information r1 and feature vector V1 for the first case, resulting in the values ​​shown in Table 2. Next, when information about the second case is stored, a weight vector W2 for the second case can be calculated based on the weight vector W1 for the first case, and the pass success / failure information r2 and feature vector V2 for the second case, resulting in the values ​​shown in Table 2. Similarly, a weight vector W3 for the first case can also be calculated, and by repeating these calculations, the weight vector W is updated, and the accuracy of the weight vector W improves as the number of cases increases.

[0040] [Table 2]

[0041] In this embodiment, case data is accumulated for all roundabouts in Japan, for example, and the weight vector W is calculated. Therefore, the passing success rate and the passing failure rate are calculated based on the passing success / failure information at a plurality of roundabouts.

[0042] By calculating the weight vector W as described above, the passing failure rate Pa of a vehicle attempting to pass through a roundabout can be calculated. The control unit 2 can then calculate the passing cost incurred at the roundabout based on the route the vehicle is guided to and the passing failure rate Pa. Specifically, if the cost for a vehicle to pass through the guided exit without going around the roundabout is C1 and the cost for the vehicle to go around the roundabout once is C2, the passing cost C3 is the sum of the cost C1 and the value obtained by multiplying the cost C2 by the passing failure rate Pa. More specifically, for example, if the cost C1 is 0.2, the cost C2 is 1, and the passing failure rate Pa is 0.4, the passing cost C3 is 0.6. In this case, the cost C1 may be set to be larger the longer the distance from the entrance to the guided exit, and the larger the angle (e.g., 0° or more and less than 360°, with clockwise being positive) between the direction of the entrance and the direction of the exit. The cost C2 may be set to be larger the larger the diameter of the roundabout. Such costs are set at intersections other than roundabouts as well, and are set to appropriate values ​​depending on whether there are traffic lights and the direction of travel (turn left, turn right, or go straight). The control unit 2 is configured to be able to calculate the total cost of the searched route.

[0043] An example of the route creation process executed by the control unit 2 will be described below with reference to the flowchart of FIG.

[0044] When the passenger inputs a destination by operating the operation unit 5, the control unit 2 searches for multiple routes from the current location to the destination. If the searched multiple routes include a route that passes through a roundabout, the control unit 2 executes the route creation process shown in FIG. 4. First, the control unit 2 determines a point X that is beyond the roundabout as viewed from the current location (S200). At this time, it is preferable that the point X is a location that many routes pass through, such as near an intersection where major streets intersect. Next, the control unit 2 acquires a weight vector W from the server SV (S210) and calculates a feature vector V that indicates the conditions at that time (S220, acquisition step). Next, the control unit 2 calculates a passage failure rate P based on the weight vector W and the feature vector V (S230, success rate calculation step) and calculates a passage cost C3 (S240). Furthermore, the control unit 2 calculates a passage arrival cost C4 for passing through the roundabout from the current location to point X based on the passage cost C3 (S250). That is, the sum of the costs incurred at points other than the roundabout on the route from the current position to point X and the passing cost C3 becomes the passing arrival cost C4.

[0045] Next, the control unit 2 calculates a non-passing arrival cost C5 for reaching point X from the current location for a route that does not pass through a roundabout (S260). Furthermore, the control unit 2 determines whether there is a route for which the non-passing arrival cost C5 has not been calculated and which passes through point X without passing through a roundabout (S270). If there is a route for which the non-passing arrival cost C5 has not been calculated (Y in S270), the control unit 2 returns to S260. On the other hand, if the non-passing arrival cost C5 has been calculated for all routes that can reach point X without passing through a roundabout (N in S270), the control unit 2 compares the passing arrival cost C4 with the non-passing arrival cost C5 and selects the route with the lowest cost (S280). The control unit 2 creates a route from the current location to the destination that includes the selected route (S290), and ends the route creation process. The control unit 2 guides the vehicle to the route created in S290.

[0046] A specific example of how the control unit 2 selects a route will be described. As shown in FIG. 5, consider the case where a through route RT1 that passes through a roundabout and a non-through route RT2 that does not pass through a roundabout are searched for as routes from the current location A to point X. In this case, assume that the through cost C3 is calculated to be 0.6, for example. Since the through route RT1 is a straight route except for the roundabout, the cost outside the roundabout is set to 0, and the through arrival cost C4 for the through route RT1 is 0.6. On the other hand, for the non-through route RT2, for example, if the cost of turning left at intersection CR1 is 0.2, the cost of turning right at intersection CR2 is 0.4, and the cost of turning left at intersection CR3 is 0.2, the non-through arrival cost C5 is calculated to be 0.8. Therefore, the through arrival cost C4 is lower than the non-through arrival cost C5, and the control unit 2 selects the through route RT1 to create a route to the destination.

[0047] In the above example, the cost for going straight was set to 0, but the cost for going straight may be set depending on the presence or absence of traffic lights, the presence or absence of stop lines, the width of the road, the speed limit, and the like.

[0048] With the above configuration, the route with the lowest cost is selected from among the routes from the current position to point X, and a route to the destination is created that includes this route, and the vehicle is guided along this route, thereby enabling route guidance that is low cost.

[0049] Furthermore, by calculating the passing success rate and the passing failure rate based on the passing success rate information at multiple roundabouts, it is possible to calculate the passing success rate and the passing failure rate even when attempting to pass through a roundabout with little passing success rate information, such as a roundabout with little traffic volume or a newly constructed roundabout.

[0050] Furthermore, by including both static information determined by the structure of the roundabout and dynamic information that changes depending on the situation when the vehicle passes through, the difficulty of passing that is specific to the roundabout that the vehicle is trying to pass through can be used as a parameter, as well as the difficulty of passing that changes depending on the situation, thereby improving the accuracy of calculating the passing success rate and passing failure rate.

[0051] The present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.

[0052] For example, in the above embodiment, the passing success rate and the passing failure rate are calculated based on the passing success / failure information at multiple roundabouts, but the passing success rate and the passing failure rate may be calculated based on the passing success / failure information specific to the roundabout that the vehicle is about to pass through. That is, a weight vector may be calculated for each roundabout, and the passing success rate (passing failure rate) may be calculated based on the weight vector of the roundabout that the vehicle is about to pass through. In this case, the passing parameters may be composed of only dynamic information.

[0053] Furthermore, in the above embodiment, the passage parameters include both static information and dynamic information, but the passage parameters may be composed of only one of static information and dynamic information. Furthermore, the static information is exemplified as the number of exits, diameter, and number of lanes at a roundabout, and the dynamic information is exemplified as whether route guidance is being performed when a vehicle passes through the roundabout, the number of exits to be passed, and the number of times the vehicle has passed through the roundabout in the past. However, the passage parameters may include, as static information, the presence or absence of a center island at the roundabout or the presence or absence of overlapping floors, and as dynamic information, the weather and time of day. Any item that has a significant impact on whether or not the vehicle passes through may be used as a passage parameter. Furthermore, the passage parameters may include at least one of these parameters as appropriate.

[0054] In the above embodiment, the passing cost is calculated based on both the distance from the entrance where the vehicle enters the roundabout to the guided exit and the angle between the direction of the entrance and the direction of the exit, but the passing cost may be calculated based on at least one of the distance and the angle. Also, a cost may be set in advance for each combination of entrance and exit.

[0055] Although the best configurations and methods for carrying out the present invention have been disclosed above, the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described mainly with reference to specific embodiments, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Therefore, the above-disclosed descriptions limiting the shape, material, etc. are provided as examples to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, descriptions using names of components that are free from some or all of the limitations on shape, material, etc. are included in the present invention. [Explanation of symbols]

[0056] 1. Navigation devices 2. Control unit (success rate calculation unit, route search unit, guidance unit, cost calculation unit) 8. Communication section (acquisition section)

Claims

1. a route search unit that searches for multiple routes to a destination of a target moving object; a success rate calculation unit that, when a first route among the plurality of routes passes through a first roundabout, calculates a passing success rate of the first roundabout based on passing condition information indicating structural characteristics of the first roundabout and environmental characteristics at the time of passing through the first roundabout, and coefficient information; a cost calculation unit that calculates a passing cost of the first roundabout based on a route portion of the first route at the first roundabout and the passing success rate, A navigation device characterized in that the coefficient information is generated based on case data including information on the success or failure of each roundabout in the past when multiple moving bodies have passed through multiple roundabouts, and information on past passing conditions that indicate the structural characteristics of each roundabout and the past environmental characteristics when each moving body passed through each roundabout.

2. 2. The navigation device according to claim 1, wherein the past passage success / failure information indicates a failure to pass through a roundabout if the plurality of moving bodies has circled the roundabout more than once when passing through each of the plurality of roundabouts.

3. The navigation device according to claim 1, characterized in that, when the plurality of mobile bodies pass through the plurality of roundabouts, the past passage success / failure information is determined to be successful when, for a mobile body receiving route guidance, the mobile body passes through the guided exit without going around the roundabout, and when, for a mobile body not receiving route guidance, the mobile body passes through the exit without going around the roundabout.

4. The navigation device according to claim 1, characterized in that the past passage condition information includes as the structural features at least one of the following: the number of exits from the circular route at each of the circular intersections when the multiple moving bodies passed through the multiple circular intersections; the diameter of the circular route; the presence or absence of a central island on the inner side of the circular route; the number of lanes on the circular route; and the number of levels if at least a portion of the circular route has a hierarchical structure in which two levels are stacked one on top of the other.

5. The navigation device according to claim 1, characterized in that the cost calculation unit calculates the passing cost based on at least one of the distance from the entrance through which the target moving body enters the first roundabout to the guided exit when the target moving body is guided along the first route, and the angle between the direction in which the entrance extends and the direction in which the exit extends.

6. a route search step of searching for a plurality of routes to a destination of the target moving object; a success rate calculation step of calculating, when a first route among the plurality of routes passes through a first roundabout, a passing success rate of the first roundabout based on passing condition information indicating structural characteristics of the first roundabout and environmental characteristics at the time of passing through the first roundabout, and coefficient information; a cost calculation step of calculating a passing cost of the first roundabout based on a route portion of the first route at the first roundabout and the passing success rate, A navigation method characterized in that the coefficient information is generated based on case data including information on the success or failure of each roundabout in the past when multiple moving bodies passed through multiple roundabouts, and information on past passing conditions that indicate the structural characteristics of each roundabout and the past environmental characteristics when each moving body passed through each roundabout.

7. 7. A navigation program for causing a computer to execute the navigation method according to claim 6.

8. 8. A computer-readable recording medium storing the navigation program according to claim 7.

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