Navigation device

Abstract

To make guidance provided by a navigation device more intuitively understandable.SOLUTION: A navigation device according to the present disclosure is the navigation device mounted on a vehicle and provides guidance for a route in which the vehicle travels, and includes a position information acquisition unit, a storage unit, an output unit that outputs information to a user, and a control unit. The position information acquisition unit acquires the current position of the vehicle. The storage unit stores map information. The control unit extracts guidance points on the route on the basis of the current position and the map information, estimates the predicted time required to reach the guidance point, and makes the output unit output the predicted time.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a navigation device. [Background technology]

[0002] A vehicle guidance device has been disclosed that provides guidance to a destination or a course change point not by the remaining distance, but by providing sensory expressions such as "There's still a long way to go" and "Almost there" (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-35847 Summary of the Invention [Problem to be solved by the invention]

[0004] When using sensory expressions to guide users, there is a possibility that the expressions may not match the user's senses because different people interpret them differently. Also, guidance based on remaining distance may not be intuitively understandable.

[0005] An object of the present disclosure, made in consideration of the above circumstances, is to make guidance provided by a navigation device easier to understand intuitively. [Means for solving the problem]

[0006] A navigation device according to one embodiment of the present disclosure that solves the above-mentioned problems is a navigation device that is mounted on a vehicle and provides guidance on a route along which the vehicle travels, and includes a location information acquisition unit that acquires the current location of the vehicle, a memory unit that stores map information, an output unit that outputs information to a user, and a control unit that extracts a guidance point on the route based on the current location and the map information, estimates a predicted time required to reach the guidance point, and outputs the predicted time to the output unit. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a navigation device that, when performing route guidance, communicates a guidance point on a route in a manner that is easy to grasp intuitively by using the time it takes to reach the guidance point, thereby making it easier to understand the guidance provided by the navigation device intuitively. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a schematic configuration of a navigation device according to an embodiment of the present disclosure. [Diagram 2] 2 is a functional block diagram showing a schematic configuration of a control unit in FIG. 1. [Diagram 3] FIG. 2 is a diagram for explaining an example of guidance to a guide point provided by the navigation device of FIG. [Figure 4] 2 is a flowchart showing an example of a process executed by a control unit in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the drawings used in the following description are schematic. The dimensions and ratios in the drawings do not necessarily correspond to the actual ones.

[0010] (System Overview) A navigation device 10 according to an embodiment of the present disclosure is a device that is mounted on a vehicle, displays a map to a user who is a passenger of the vehicle, and guides the user along a route to a destination. The vehicles include, but are not limited to, passenger cars, trucks, buses, large and small special purpose vehicles, etc. The vehicles include various types of vehicles that will be realized in the future. For example, the vehicles may include autonomous vehicles, amphibious vehicles, and air-land vehicles, etc.

[0011] 1, the navigation device 10 may be configured to be able to communicate with various servers 30 outside the vehicle via a communication network 20. The communication network 20 includes the Internet, a VPN (Virtual Private Network), a mobile communication network, and the like.

[0012] The server 30 can provide traffic information to the navigation device 10. The server 30 includes servers of government agencies in charge of traffic management, road managers, businesses that provide traffic information, and the like. The server 30 can provide road congestion information, congestion information, accident information, and the like. The server 30 may also include a server that provides road map information.

[0013] (Configuration of navigation device) The navigation device 10 includes a communication unit 11, a storage unit 12, a positioning unit 13, an input unit 14, an output unit 15, and a control unit 16.

[0014] The communication unit 11 can connect to the communication network 20 by wireless communication means and acquire information from the server 30. The wireless communication means includes the fourth generation mobile communication system (4G), the fifth generation mobile communication system (5G), Wi-Fi (registered trademark), and WiMAX (Worldwide Interoperability for Microwave Access). The communication unit 11 may further support Dedicated Short Range Communication (DSRC) and the like. The communication unit 11 may also be configured to be able to receive a traffic information service using broadcast waves such as FM multiplex broadcasting.

[0015] The storage unit 12 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, a random access memory (RAM) or a read only memory (ROM). The RAM is, for example, a static random access memory (SRAM) or a dynamic random access memory (DRAM). The ROM includes, for example, an electrically erasable programmable read only memory (EEPROM). The magnetic memory may include, for example, a hard disk. The optical memory may include, for example, a compact disc (CD), a digital versatile disc (DVD), and a Blu-ray (registered trademark) disc (BD). The storage unit 12 functions, for example, as a main storage device, an auxiliary storage device, or a cache memory. The storage unit 12 stores a program executed by the control unit 16, data used in the operation of the control unit 16, data obtained by the operation of the control unit 16, and the like.

[0016] The memory unit 12 can store road map information. The road map information includes road network information, background map information, facility information, etc. The road network information expresses the connections and shapes of roads using points called nodes and lines called links. The position information of the nodes and links is specified by latitude and longitude. The background map information includes information on the shapes of land, buildings, rivers, railway lines, etc. in the background of the road. The facility information is information on facilities included in the road map. The memory unit 12 may store road map information at all times. The memory unit 12 may temporarily store road map information read, as necessary, via the communication unit 11 from the server 30 that provides the road map.

[0017] The positioning unit 13 detects the position of the vehicle equipped with the navigation device 10. The positioning unit 13 functions as a position information acquisition unit. The position detected by the positioning unit 13 can be a position represented by latitude, longitude, and the like. The positioning unit 13 can include a receiver compatible with a global navigation satellite system (GNSS) using artificial satellites. Receivers compatible with the GNSS include a global positioning system (GPS) receiver. Using a signal from the GPS receiver, latitude and longitude information of the current position of the vehicle can be obtained. The signal from the GPS receiver can be combined with various detection devices such as a direction sensor, a steering angle sensor, and a distance sensor. In this way, it is possible to improve the accuracy of position detection and estimate the position in a place where radio waves from a satellite cannot reach. Note that instead of or in addition to the GPS receiver, a receiver compatible with another GNSS may be adopted. Examples of other GNSS include a satellite positioning system using GLONASS, Galileo, Compass, and a quasi-zenith satellite.

[0018] The input unit 14 accepts input to the navigation device 10. The input unit 14 may include a touch panel formed integrally with the display 17 described below, and a microphone that accepts voice input. The touch panel is a device that detects input by the user's touch. The touch panel accepts input in conjunction with the display content of the display 17. Touch panels include various types such as capacitive, resistive, and surface acoustic wave types. The microphone converts input voice into a voice signal and outputs it. To convert the voice signal output by the microphone into text, the navigation device 10 may be configured to perform voice recognition processing in the control unit 16 or the like. The input unit 14 may further include a connector that receives input from an external input device.

[0019] The output unit 15 outputs information processed by the navigation device 10 to the user. The output unit 15 includes a display 17 and a speaker 18. The display 17 and the speaker 18 may be shared with devices for other purposes in the vehicle. The output unit 15 may include the display 17, the speaker 18, and connectors for outputting information to other output devices.

[0020] The display 17 is a device that displays an image based on an image signal obtained as a result of processing by the control unit 16. The display 17 may be any of various displays, such as a liquid crystal display (LCD), an organic electro-luminescence (EL) display, an inorganic EL display, or a plasma display panel (PDP). The display may also be a head up display (HUD). The HUD may project a display image onto the front windshield or a combiner arranged on the dashboard.

[0021] The speaker 18 converts an audio signal into physical vibrations to generate sound in space. The speaker 18 may be an audio speaker installed in a vehicle. The speaker 18 may be disposed in a door, dashboard, pillar, or the like of the vehicle. A known general speaker may be used as the speaker 18.

[0022] The control unit 16 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination thereof. The processor is a general-purpose processor such as a central processing unit (CPU) or a graphics processing unit (GPU), or a dedicated processor specialized for a specific process. The programmable circuit is, for example, a field-programmable gate array (FPGA). The dedicated circuit is, for example, an application specific integrated circuit (ASIC).

[0023] The control unit 16 controls each part of the navigation device 10 and executes various calculation processes related to the operation of the navigation device 10. The control unit 16 operates each part of the navigation device 10 and makes the navigation device 10 function.

[0024] (Control Unit Configuration) In one embodiment, the control unit 16 includes a destination acquisition unit 16a, a route setting unit 16b, a guide point extraction unit 16c, a time prediction unit 16d, an accuracy estimation unit 16e, a notification determination unit 16f, a notification content generation unit 16g, and a voice synthesis unit 16h, as shown in FIG. 2. Each of these units may be a hardware module or a software module. Each of these units may be integrated with each other and / or may be divided into a plurality of units. The processing executed by each unit of the control unit 16 can be rephrased as being executed by the control unit 16.

[0025] The destination acquisition unit 16a acquires information about a destination from a user via the input unit 14. To allow a user to easily input a destination, the destination acquisition unit 16a may provide a function for searching for a destination from road map information stored in the storage unit 12. The destination may be searched for, for example, using an address and a telephone number of a facility included in the facility information of the road map information.

[0026] The route setting unit 16b can search for a route from the current position detected by the positioning unit 13 to the destination acquired by the destination acquisition unit 16a based on the road map information stored in the memory unit 12. The route setting unit 16b can extract multiple routes and present them on the display 17. The user can select one route from the multiple routes. The route setting unit 16b sets the route selected by the user as the route to the destination. The route setting unit 16b can search for and set the route again when the user requests a re-search for the route, when the vehicle equipped with the navigation device 10 deviates from the set route, etc.

[0027] The guide point extraction unit 16c extracts guide points for which a predicted time required to reach the point is to be notified to the user. The guide points are points on a set route. The guide points include, for example, intersections on the route where a right or left turn is made, or branch points where the route branches off to the left and right. The guide points may also include points on the route where there are landmarks, and points where there are facilities related to road traffic. The landmarks may include famous buildings, bridges, and train stations. The facilities related to road traffic may include, for example, gas stations and drive-ins. The guide points may also include a destination.

[0028] The guide point extraction unit 16c may extract the next guide point on the route from the current position. For example, the guide point extraction unit 16c extracts the next guide point when the previous guide point is passed. The guide point extraction unit 16c may extract guide points after the next guide point according to a predetermined condition or according to an instruction from the user via the input unit 14.

[0029] The time prediction unit 16d predicts the time it will take for the vehicle equipped with the navigation device 10 to reach the guide point. The time predicted by the time prediction unit 16d is called the predicted time. For example, the time prediction unit 16d calculates the distance from the current position to the guide point based on road map information. The time prediction unit 16d may calculate the time it will take to travel the distance to the guide point when the vehicle equipped with the navigation device 10 travels at the predicted speed. The time prediction unit 16d may use the most recent average speed at which the vehicle has actually traveled as the predicted speed. The most recent average speed may be the average speed from a predetermined time before the current time to the current time. The time prediction unit 16d may also use the speed limit of the route on which the vehicle travels as the predicted speed. The speed at which the vehicle actually traveled may be calculated by the control unit 16 based on the change in the current position detected by the positioning unit 13. Alternatively, the control unit 16 may acquire speed information measured for a speedometer from the vehicle equipped with the navigation device 10.

[0030] When the time prediction unit 16d acquires traffic information indicating the congestion state on the planned route from the server 30 via the communication unit 11, the time prediction unit 16d may estimate the predicted time by taking the traffic information into consideration. For example, when the traffic information includes information indicating the level of congestion on the route, the time prediction unit 16d estimates the average traveling speed of the congested section and uses the average traveling speed in calculating the predicted time. When there is heavy congestion on the route or when an accident has occurred, the time prediction unit 16d may determine that it is impossible to calculate the predicted time.

[0031] When there are traffic lights on the route, the time prediction unit 16d may calculate an average waiting time based on the interval at which the traffic lights switch, and use the calculated average waiting time for calculating the predicted time. The time prediction unit 16d may use the standard switching time of the traffic lights as the time for the traffic lights to switch. Alternatively, the time prediction unit 16d may be configured to store the switching time of each traffic light in the storage unit 12, or to acquire it from the server 30. In addition, the time prediction unit 16d may take into account right turns, left turns, temporary stops, and the like on the route as factors that affect the predicted time.

[0032] The accuracy estimation unit 16e evaluates the prediction accuracy of the predicted time required to reach the guide point. Various methods can be adopted for evaluating the prediction accuracy. For example, the accuracy estimation unit 16e estimates the error rate of the predicted time as the prediction accuracy. The error rate can be the ratio of the estimated value of the error of the predicted time to the predicted time. That is, the error rate is calculated by the following formula. Error rate = Estimated error in forecast time / forecast time

[0033] For example, the accuracy estimation unit 16e extracts factors that cause errors in the predicted time on the route, quantifies the errors estimated by them, and sums them up. For example, congestion on the route is a factor that causes errors in the predicted time. The accuracy estimation unit 16e calculates the error in the predicted time according to the congestion state. The error in the predicted time according to the congestion state may be determined based on information previously stored in the storage unit 12 or the external server 30. In addition, when there are traffic lights, the timing of the switching of the traffic lights may cause prediction errors. For example, the accuracy estimation unit 16e may add the difference between the average traffic light waiting time and the maximum traffic light waiting time to the estimated value of the error in the predicted time. Furthermore, when making right turns, left turns, and stopping on the route, there are individual differences in the way of decelerating and accelerating at the points where these are performed, which causes errors in the predicted time. Therefore, the accuracy estimation unit 16e adds the estimated value of the error in the predicted time according to the number of these points.

[0034] The notification determination unit 16f determines whether or not to notify the user of the predicted time. In one embodiment, the notification determination unit 16f may determine not to notify the user of the predicted time when the predicted time is shorter than a predetermined time. The predetermined time is, for example, 10 seconds, 20 seconds, or 30 seconds, but is not limited to these. The notification determination unit 16f may determine not to notify based on the distance to the guide point instead of the predicted time. When the distance to the guide point is short, the time to reach the guide point may change significantly due to the vehicle decelerating in front of the guide point. For this reason, the predicted time may differ from the time when the vehicle actually reaches the guide point. Therefore, notifying the user of the predicted time just before the guide point may cause misunderstanding or confusion. By not notifying the user of the predicted time, the control unit 16 can avoid the occurrence of the above-mentioned misunderstanding or confusion.

[0035] In one embodiment, even if the time prediction unit 16d determines that it is impossible to calculate the predicted time during the process of calculating the predicted time, the notification determination unit 16f may determine not to notify the predicted time. Therefore, when there is heavy traffic on the route or when an accident has occurred, the predicted time is not notified. In this way, when it is considered that the prediction accuracy of the arrival time to the guide point is extremely low, it is possible to avoid notifying the user of a predicted time with low reliability.

[0036] The notification determination unit 16f may determine that the predicted time should be notified when the error rate estimated by the accuracy estimation unit 16e is equal to or less than a predetermined threshold, and that the predicted time should not be notified when the error rate exceeds the predetermined threshold. The predetermined threshold can be set to, for example, 0.1, 0.2, 0.3, or the like. That is, the accuracy estimation unit 16e determines that the predicted time should be notified if the accuracy of the estimated predicted time is high, and that the predicted time should not be notified if the accuracy of the estimated predicted time is low. This allows the navigation device 10 to notify the user of only highly reliable predicted times.

[0037] The notification content generating unit 16g generates the content to be notified to the user using the predicted time predicted by the time predicting unit 16d. The notification content includes messages such as "Keep straight ahead for T1 minutes," "Keep straight ahead to P1. It takes about T2 minutes to reach P1," and "Turn right in T3 seconds." Here, T1 to T3 represent time, and P1 represents the name of a place. When the notification determining unit 16f determines not to notify the predicted time, the notification content generating unit 16g may generate notification content that notifies the user of the distance to the guide point.

[0038] The voice synthesis unit 16h performs voice synthesis processing to generate human voice from the text of the notification content generated by the notification content generation unit 16g in order to provide a voice signal to the speaker 18. Known technologies such as waveform concatenation type voice synthesis and statistical model type synthesis can be adopted as the voice synthesis technology. The voice synthesis unit 16h outputs a voice signal to the speaker 18, so that the user can know the estimated time it will take to reach the guide point from the voice output from the speaker 18.

[0039] FIG. 3 shows an example of a notification by the navigation device 10. As shown on the display 17, the route on which the vehicle equipped with the navigation device 10 is scheduled to travel is to go straight and then turn right at intersection X. Intersection X is set as the next guide point. The control unit 16 predicts the time required to reach intersection X, and notifies the user by voice and / or by displaying text on the display 17 that the vehicle will reach the right turn point after the predicted time has elapsed. As an example, the content of the voice notification is written in the balloon in FIG. 3. This allows the user to know in advance that the vehicle will turn right after the predicted time has elapsed. For example, when there are multiple lanes, the user can move the vehicle to a lane closer to the right. This allows the user to smoothly turn right at intersection X.

[0040] The timing for notifying the user of the estimated time to reach the guide point may be set according to various conditions. For example, the control unit 16 may be set to notify the user of the estimated time to reach the guide point when the previous guide point has been passed and / or when the distance to the next guide point has reached a predetermined length. The control unit 16 may also be set to notify the user of the estimated time to reach the next guide point or destination at predetermined time intervals.

[0041] (Processing performed by the control unit) An example of a process flow executed by the control unit 16 of the navigation device 10 will be described below with reference to FIG. 4. FIG. 4 shows an example of an information processing method executed by the control unit 16. The method disclosed in this specification can be executed by a processor included in the control unit 16 according to a program. Such a program can be stored in a non-transitory computer-readable medium. Examples of non-transitory computer-readable media include, but are not limited to, a hard disk, a RAM, a ROM, a flash memory, a CD-ROM, an optical storage device, a magnetic storage device, and the like.

[0042] The user can select whether or not to be notified based on predicted time through the input unit 14 of the navigation device 10. The user can make such a selection or change the selection before or during route guidance. The following processing is based on the premise that the user has selected guidance based on predicted time.

[0043] First, the control unit 16 acquires the destination input by the user via the input unit 14 (S01).

[0044] The control unit 16 searches for a route from the current position detected by the positioning unit 13 to the destination, and sets the route (S02).

[0045] The control unit 16 extracts guide points from the route (S03). The extracted guide points include the guide point where the vehicle will arrive next.

[0046] The control unit 16 calculates the distance from the vehicle in which the navigation device 10 is installed to the guide point (S04).

[0047] The control unit 16 determines whether a notification condition for notifying the user of a predicted time to a guide point is satisfied (S05). For example, the control unit 16 may notify the user of a predicted time to the next guide point when passing one of the guide points. The control unit 16 may also notify the user of a predicted time to the next guide point or the destination which is the final guide point every time a predetermined time has elapsed. Furthermore, the control unit 16 may notify the user of a predicted time to the next guide point when the distance to the next guide point is within a predetermined distance. Note that if the distance to the guide point is not used to determine the notification condition, S04 may be executed after S05.

[0048] When the notification condition is satisfied in S05 (S05: Yes), the control unit 16 proceeds to the process of S06. When the notification condition is not satisfied in S05 (S05: No), the control unit 16 returns to the process of S03.

[0049] When the notification condition is satisfied in S05 (S05: Yes), the control unit 16 calculates a predicted time to the guide point (S06).

[0050] The control unit 16 estimates an error in the calculated predicted time (S07). Traffic congestion on the route along which the vehicle travels, traffic lights, stop signs, right and left turns on the route, and the like can be taken into consideration as factors that cause an error in the predicted time. The control unit 16 can estimate the longest time that is expected to take to reach the guidance point from the current position, and determine the difference between this and the predicted time as the error. The longest time may be calculated by adding together the longest time it takes to pass through a congested section, the longest time spent waiting at a traffic light, and the like.

[0051] The control unit 16 determines whether the error rate of the predicted time is equal to or less than a threshold value (S08). If the error rate is equal to or less than the threshold value (S08: Yes), the control unit 16 proceeds to S10. If the error rate exceeds the threshold value (S08: No), the control unit 16 proceeds to S09.

[0052] If the error rate exceeds a predetermined value (S08: No), the control unit 16 may switch from the notification based on the predicted time to the notification based on the distance to the guide point (S09). In the following description, it is assumed that the switching to the notification based on the distance (S09) is not performed.

[0053] The control unit 16 may have other judgment conditions instead of or in addition to the judgment condition based on the error rate in S08. For example, the control unit 16 may determine not to notify the predicted time when there is a heavy traffic jam on the route to the guidance point or when an accident has occurred based on the traffic information received from the server 30. In addition, the control unit 16 may determine not to notify the predicted time to the next guidance point when the distance to the next guidance point is short.

[0054] Next, the control unit 16 generates notification content to be notified to the user (S10). The notification content includes a predicted time to the guide point. The notification content may include information about the guide point. For example, the notification content may include the name of the guide point. Furthermore, if the guide point is a right turn point or a left turn point, the notification content may include information about that. If there is no right or left turn until the guide point, the notification content may include information indicating that the user should continue straight along the road until the guide point.

[0055] The control unit 16 causes the output unit 15 to output the legal content (S11). The control unit 16 displays the notification content as text on the display 17 and / or converts it into an audio signal and causes the speaker 18 to output it as audio (S11). By being notified of the time remaining until the guide point is reached, the user can intuitively grasp the approach of the guide point. If the user is notified of the distance remaining until the guide point, the time it takes to reach the guide point will differ depending on the speed, even if the distance is the same. By notifying the user of the time remaining until the guide point, the user can intuitively grasp the amount of time remaining until the guide point.

[0056] Unless the destination is reached (S12: No), the control unit 16 returns to S03 and continues route guidance including notification of the estimated time to the guide point. When the destination is reached (S12: Yes), the control unit 16 ends the process.

[0057] As described above, according to this embodiment, when route guidance is provided, a guide point on a route can be communicated in an intuitive manner using the time it takes to reach the guide point, thereby making it easier to understand the guidance provided by the navigation device 10 intuitively.

[0058] The present invention is not limited to the above-described embodiment, and many variations and modifications are possible. For example, the functions included in each means, step, etc. can be rearranged so as not to cause logical inconsistencies, and multiple means or steps can be combined into one or divided.

[0059] In the above embodiment, the accuracy of the predicted time is determined by using the error rate of the predicted time based on the estimated error of the predicted time, but the method of determining the accuracy of the predicted time is not limited to this.

[0060] For example, it is generally assumed that errors in the predicted time are likely to occur in urban areas due to the effects of traffic congestion, etc., while errors in the predicted time are unlikely to occur in suburban areas with little traffic. Therefore, the road map may be divided into urban areas and suburban areas, etc., and the accuracy of the predicted time may be determined based on the proportion of urban areas included in the route on which the vehicle travels.

[0061] Machine learning may also be used to determine the accuracy of the predicted time. That is, a large amount of data in which information on the vehicle's route is input and the error between the predicted time and the actual time is output is used as learning data, and a pre-trained model is generated by a machine learning computer. Using this trained model, the control unit 16 may estimate the error in the predicted time for the route to be traveled.

[0062] In the above embodiment, the processing of the navigation device 10 is executed by the control unit 16 in the navigation device 10. However, at least a part of the processing of the control unit 16 may be executed by a computer external to the navigation device 10 via the communication network 20. For example, the navigation device 10 may cause an external computer to calculate a predicted time until reaching a guide point, estimate an error in the predicted time, and the like. [Explanation of symbols]

[0063] 10 Navigation devices 11 Communications Department 12 Storage section 13 Positioning unit (location information acquisition unit) 14 Input section 15 Output section 16 Control section 16a Destination acquisition part 16b Route setting section 16c Guidance point extraction section 16d Time prediction section 16e Accuracy estimation part 16f Notification judgment section 16f Notification content generation unit 16e Speech synthesis section 17 Display 18 Speaker 20 Network 30 Servers

Claims

1. A navigation device mounted on a vehicle for providing guidance on a route along which the vehicle travels, a location information acquisition unit that acquires a current location of a vehicle; A storage unit that stores map information; an output unit for outputting information to a user; a control unit that extracts a guide point on the route based on the current position and the map information, estimates a predicted time required to reach the guide point, and outputs the predicted time to the output unit; A navigation device comprising:

2. The navigation device according to claim 1 , wherein the control unit does not output the predicted time when the distance from the current position to the guide point is shorter than a predetermined distance.

3. The navigation device according to claim 1 , wherein the control unit evaluates accuracy of the predicted time and determines whether or not to output the predicted time based on the accuracy.

4. The navigation device according to claim 3 , wherein the control unit estimates an error rate of the predicted time as the accuracy, and outputs the predicted time when the error rate is equal to or less than a predetermined threshold value.

5. The navigation device according to claim 1 , further comprising a communication unit capable of acquiring traffic information, wherein when the control unit acquires traffic information indicating a congestion state of the route, the control unit estimates the predicted time in accordance with the traffic information.

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