JP2011145090A - Vehicle navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To guide a temporary stop in a mode based on a current position positioning precision. <P>SOLUTION: The navigation system calculates a route where a vehicle travels on map data as a scheduled traveling route. When it is determined that a place where a vehicle should stop temporarily exists on the scheduled traveling route and branching points where a road in which the vehicle is located currently is branched to a plurality of branch roads exist between the current position and the place where the vehicle should stop temporarily, marks indicating the degree of possibility of guidance for the place where the vehicle should stop temporarily becoming wrong guidance are calculated, on the basis of at least one of an angle α between the branch road and a road where the vehicle is located currently, the minimum value B out of angles of the branch road to one or a plurality of branch roads where no places in which the vehicle should stop temporarily exist, width of a road where the vehicle is located currently, and the largest width of a road out of the plurality of branch roads for each of branch roads where a place in which the vehicle should stop temporarily exists. A notification form of temporary stop guidance is changed according to the values of the calculated marks. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle navigation apparatus.

  2. Description of the Related Art Conventionally, various guidance such as routes and signs are provided to a driver in advance using a navigation device mounted on a vehicle.

  As a technique using such a navigation device, in Patent Document 1 below, a plurality of forward road information is created corresponding to a candidate road ahead from a junction or intersection, and the plurality of forward road information is similar. In the case where the vehicle is running, it is described that any one of the plurality of road information ahead is sent to the travel control device or the alarm device to perform the travel control operation or the alarm operation.

  Further, in Patent Document 2 below, a candidate road is searched from the estimated position of the vehicle, whether or not there is a small angle branch point that branches at a small angle on the candidate road, and each road at the small angle branch point is detected. It is described that it is determined which road the vehicle has traveled in consideration of the width.

JP 2006-123690 A JP 2005-114632 A

  In order to support safe driving of the vehicle, when there is a place to be temporarily stopped on the traveling route of the vehicle, the navigation device can notify the driver in advance. Thereby, the driver can recognize in advance the place to be temporarily stopped and can perform necessary driving operations (deceleration, stop, etc.).

  On the other hand, when using the navigation device, the current position detected for the vehicle is mapped to the corresponding position on the map data through a process called match mapping. The navigation device uses the mapped position for various processes such as route search.

  In order to detect the current position of the vehicle, there is a method of measuring the current position using a signal from a GPS satellite (referred to as satellite navigation or GPS navigation). However, there is a possibility that an error is included in the received signal depending on the communication situation when receiving the GPS signal, and there is a possibility that a deviation occurs between the actual position and the position mapped on the map data.

  In addition, there is a method (autonomous navigation) in which the current position of the vehicle is detected by cumulatively obtaining the position of the vehicle from the departure place using an orientation sensor or a distance sensor. In the case of this method as well, there is a possibility that a difference between the actual position and the position mapped on the map data may occur due to accumulation of sensor errors and errors due to the running state of the vehicle.

  Moreover, even if the detected current position is accurate, there is a possibility that some error may be included when mapping this on the map data through the match mapping process. As a result, the actual position and the navigation device There is a possibility that a deviation will occur between the position on the map data recognized by the.

  When the vehicle travels on a road form in which such a deviation is likely to occur, there is a possibility that the navigation device may perform erroneous guidance, such as issuing a guidance for temporary stop when the vehicle is not a place to be temporarily stopped. Conventionally, guidance is performed in a uniform notification form without determining the degree of possibility of such erroneous guidance. However, when guidance is provided in a uniform notification form, if the guidance is incorrect, the driver may feel uncomfortable and the driving operation may be affected. In addition, the reliability of the navigation device is reduced, and the device itself may not be used.

  Therefore, a method of determining the possibility of such erroneous guidance and guiding in a notification form corresponding to the degree is desired.

  According to one aspect of the present invention, means for detecting the current position of the vehicle, means for calculating a route traveled by the vehicle on map data based on the detected current position, as the planned travel route, Based on the map data, the means for determining whether or not there is a place to be temporarily stopped on the planned travel route of the vehicle, and when it is determined that the place to be temporarily stopped exists, the vehicle There is provided a navigation device mounted on a vehicle, comprising: notifying means for notifying a driver of the vehicle prior to reaching a place to be temporarily stopped. In the navigation device, if it is determined that there is a place to be paused, a road where the vehicle is currently located is a plurality of branch roads between the current position and the place to be paused. Branch determination means for determining whether there is a branch point to branch to, and if it is determined that the branch point exists, each of the branch roads where there is a place to be temporarily stopped among the plurality of branch roads The minimum of the angle (α) between the branch road and the road where the vehicle is currently located, and the angle of the branch road with respect to the one or more branch roads where the place to be paused does not exist The place to be temporarily stopped based on at least one of the value (B), the width or lane number of the road where the vehicle is currently located, and the largest width or lane number of the plurality of branch roads In It includes a score calculating means for calculating a score indicating a degree guide is likely to be erroneous guidance you are, the. The notification means changes a form of notification of the temporary stop guidance according to the calculated magnitude of the score.

  According to the present invention, the above-described accuracy of the temporary stop prior guidance is obtained due to the deviation between the detected current position of the vehicle and the position mapped on the map data as described above. It can be judged by the score whether it is in a situation where it is not possible. Therefore, by taking a notification form according to the size of the score, a pause guidance in a situation where an accuracy higher than a predetermined level cannot be obtained, and a pause guide in a situation where a accuracy higher than a predetermined level can be obtained. , Can be notified in different forms. When highly accurate pause guidance is possible, it is possible to give a notice that draws the driver's attention relatively strongly. On the other hand, if there is a possibility that the accuracy of the pause guidance may be lowered, It is possible to make a notification that evokes a person's attention relatively weakly. Thus, since the reliability of the temporary stop guidance function can be maintained, the driver can be encouraged to continue using the function.

  According to an embodiment of the present invention, the notification means has a degree of possibility that the score calculated for all the branch roads among the branch roads where the place to be temporarily stopped is the erroneous guidance. When the threshold value is not more than the threshold value indicating high, notification of the temporary stop guidance is made via at least one of notification by sound or voice and notification by window display on the display screen of the display device. I do. Further, according to one embodiment, the notification means has a degree of possibility that the score calculated for any branch road among the branch roads where the place to be temporarily stopped is the erroneous guidance. When the threshold value indicating high is exceeded, the temporary stop guidance is notified through display of at least one of an icon and a telop on the map data displayed on the display device.

  The notification by sound or voice, and the notification through a window displayed on a display screen over a relatively wide range, urge the driver's attention more strongly than simple icon display or telop display. Therefore, in one embodiment, in a situation where the accuracy of the pause guidance is obtained at a predetermined level or more, the driver is given prior guidance for pause through the former notification. As a result, the driver can be surely recognized the presence of the temporary stop place, and thus the driving operation for the temporary stop can be prompted. On the other hand, in a situation where the accuracy of the temporary stop guidance cannot be obtained more than a predetermined value, the driver is provided with preliminary stop guidance through the latter notification. The driver can recognize that there is a temporary stop by visually recognizing the display screen. Even if the temporary stop guidance of the icon or telop display is wrong, since the icon etc. is displayed on the map data, by checking the road on which the vehicle is currently traveling on the map data, The driver can easily identify the mistake. In addition, the fact that an icon or the like has been displayed makes it possible for the driver to recognize that he / she is driving in a road environment where erroneous guidance for a temporary stop may occur, thus urging attention to driving. it can.

  According to an embodiment of the present invention, the score calculated for any branch road among the branch roads where the place to be temporarily stopped indicates that there is a high possibility of erroneous guidance. When the threshold value is exceeded, the processing by the branch determination unit and the score calculation unit is repeatedly performed until the current position of the vehicle reaches a point of a predetermined distance with respect to the place to be temporarily stopped. .

  Depending on the form of the road, the score calculation result may change as it approaches the place to be temporarily stopped. Therefore, the score calculation is repeatedly performed until the vicinity of the place to be temporarily stopped is reached. Thereby, notification can be performed when a better accuracy result is obtained.

  According to another aspect of the present invention, the score is calculated in advance, and includes score storage means for storing the score in association with the branch point on the map data. In this case, if the branch determination means determines that the branch point exists, the score stored in association with the branch point is read out. The notification means changes the notification form of the temporary stop guidance according to the size of the read score.

  According to the present invention, since the score is calculated in advance and stored in association with the branch point of the map data, real-time calculation becomes unnecessary, and the calculation load during traveling of the vehicle can be reduced. Therefore, the notification accuracy of the temporary stop guidance can be improved while reducing the cost of the navigation device. Also, if the map data is updated and the road attribute information (width etc.) that affects the score calculation is changed, the score only needs to be recalculated, so the temporary stop guidance function is maintained. Man-hours and calculation load can be kept low.

  Other features and advantages of the present invention will be apparent from the detailed description that follows.

1 is a block diagram of a navigation device according to one embodiment of the present invention. The figure which shows an example of the 1st-3rd alerting | reporting form according to one Example of this invention. The figure which shows an example of the road form which is easy to produce a misguidement about the place which should be paused according to one Example of this invention. The figure for demonstrating the method of calculating the score about the guidance of a stop according to one Example of this invention. 5 is a flowchart of a pause guidance process according to an embodiment of the present invention. 7 is a flowchart of a pause guidance process according to another embodiment of the present invention. 7 is a flowchart of a pause guidance process according to another embodiment of the present invention.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a vehicle navigation device 10 mounted on a vehicle according to an embodiment of the present invention. The device 10 includes a current position detection unit 11, a map information storage unit 12, a processing device 13, an input device 14, a display device 15, and a speaker 16.

  The current position detection unit 11 is used to improve positioning accuracy by correcting a GPS signal error using, for example, an appropriate base station or a GPS signal for measuring the position of the vehicle using an artificial satellite. A positioning signal receiving unit 21 that receives a positioning signal such as a D (differential) GPS signal, and a vehicle orientation in a horizontal plane and a tilt angle with respect to a vertical direction (for example, a tilt angle with respect to a vertical direction of a vehicle longitudinal axis and a vehicle center of gravity) And a gyro sensor 22 for detecting the amount of change in the tilt angle (for example, the yaw rate) and a vehicle speed sensor 23 for detecting the vehicle speed (vehicle speed). The current position detection unit 11 calculates the current position of the vehicle by the received positioning signal or by an autonomous navigation calculation process based on detection signals such as the vehicle speed and the yaw rate. The current position of the vehicle detected in this way is passed to the processing device 13.

  The map information storage unit 12 can be realized in any storage device (storage medium, hard disk drive, etc.), and stores map information (map data). The map information includes data necessary for drawing a map image on the display screen of the display device 15. For example, map information includes topographic map data, polygon data corresponding to various facilities, city blocks, lakes, etc., character data such as facility names and place names associated with each polygon, and data of various symbols. It has. Further, the map information includes road data indicating information related to road connection states. The road data typically includes nodes (coordinate points serving as nodes such as intersections), links (minimum units of travel paths) that are lines connecting the nodes, and distances of the links. The road data includes attribute information indicating the attribute of the road for each road. Attribute information can include arbitrary information, such as information on road types (national roads, prefectural roads, toll roads, etc.), road shape, road gradient, road curvature, road width, etc. included. Further, in this embodiment, the road data includes position information where a predetermined sign or sign is installed, and thus includes position information of a place to be temporarily stopped. For example, the road data may include position information of a place where a traffic sign indicating a temporary stop or a place where a road sign indicating a temporary stop is provided.

  The processing device 13 can be realized by an electronic control unit (ECU) that is a computer including a central processing unit (CPU) and a memory. The input device 14 is a device that can input data by the occupant, and the data input through the input device 14 is passed to the processing device 13. The result processed by the processing device 13 is displayed on the display device 15 so that the occupant can view it, and / or is output as sound or voice through the speaker 16. In this embodiment, the display screen of the display device 15 includes a touch panel that functions as the input device 14.

  The processing device 13 includes a map matching processing unit 31, a planned traveling route calculation unit 33, a display control unit 35, and a temporary stop guide unit 37.

  Based on the current position of the vehicle detected by the current position detection unit 11, the map matching processing unit 31 calculates the position on the road corresponding to the detected current position from the map information stored in the map information storage unit 12. A map matching process is performed to search for. As described above, the road data is represented as a link connecting nodes, and the link corresponds to the center line of the road. Therefore, the map matching processing unit 31 obtains (maps) the position on the corresponding link on the map data based on the detected current position of the vehicle, and recognizes the obtained position as the current position of the vehicle.

  Such map matching processing can be realized by any known method. By performing the map matching process, the error included in the received positioning signal and the detection signal such as the vehicle speed can be corrected to some extent. Data representing the current position of the vehicle as a result of the map matching process being sent to the planned travel route calculation unit 33 and the display control unit 35.

  The scheduled travel route calculation unit 33 calculates a route (scheduled travel route) on which the vehicle is scheduled to travel from the current position, based on the current position and map information of the vehicle mapped as described above. The planned travel route can include a guidance route and a travel estimation route. The guidance route is a route calculated by searching for an optimum route from the current position of the vehicle to the destination in response to the destination being input by the occupant via the input device 14. The planned travel route calculation unit 33 searches for the route to the input destination using any appropriate algorithm. Various search methods have been proposed, and a desired one can be used. When the vehicle deviates from the guidance route, the planned travel route calculation unit 33 can again search for a route from the current position of the vehicle to the destination and calculate the guidance route.

  The travel estimation route is a route calculated by, for example, a predetermined distance from the current position of the vehicle, assuming that the vehicle maintains the current traveling direction. For example, in the case of a vehicle traveling on a certain road, a route that travels along the road in a “road” is the estimated travel route. For example, when a vehicle enters a branch road at a branch point or turns to another road by turning left or right, the road to which the vehicle enters is the estimated travel route.

  The planned travel route calculated in this way is passed to the display control unit 35. The display control unit 35 reads out map data around the current position of the vehicle from the map information storage unit 12, and overlays a mark indicating the current position of the vehicle and a line indicating the planned travel route on the map data. Display on device 15. Thus, the driver of the vehicle can visually recognize where the vehicle is currently traveling. In particular, when the planned travel route is a guide route, the vehicle can reach the destination by driving along the guide route.

  The temporary stop guide unit 37 determines whether there is a place to be temporarily stopped on the planned travel route of the vehicle based on the planned travel route and the map information. As described above, the place to be temporarily stopped is stored in advance in the map information. For example, the place where the traffic sign indicating the temporary stop is installed, and the place where the road sign for prompting the stop is provided is included. Good. When there is a place to be paused, the pause guide unit 37 guides the vehicle driver that there is a place to pause before the vehicle reaches the place to pause. Notification.

  As described above, the current position of the vehicle is detected by the current position detection unit 11 based on the received positioning signal, detection signal such as the vehicle speed, and the detected current position may include an error. Even if the detected current position is correct, when the map matching processing unit 31 maps the current position on the map data, there is a possibility that the mapped position includes an error. If the current position of the vehicle on the map data includes an error, an error may occur in the planned travel route calculated as described above. Therefore, even if the navigation device recognizes that there is a temporary stop location on the planned travel route and performs notification, there is a possibility that the vehicle actually travels on a road where there is no temporary stop location. is there. Such an erroneous notification causes the driver to feel uncomfortable.

  Therefore, in the present invention, it is determined whether or not erroneous guidance is likely to occur in the temporary stop guidance, and the notification form is changed according to the degree of the situation in which erroneous guidance is likely to occur. For this reason, the temporary stop guide unit 37 has a place to be temporarily stopped on the planned travel route of the vehicle, and the vehicle currently travels from the current position to the place to be temporarily stopped. It is determined whether or not there is a branch point where the road being branched into a plurality of branch roads.

  If it is determined that the branch point exists, the temporary stop guide unit 37 evaluates whether or not the erroneous stop guidance is likely to occur based on the road branch form at the branch point. This evaluation is performed by calculating a score indicating the degree of possibility of erroneous guidance for the branch point. The higher the possibility of misguidement, the higher the score is calculated. This specific calculation method will be described later.

  The temporary stop guide part 37 changes the form of notification according to the magnitude of the score calculated for the branch point. In this embodiment, the notification is classified according to the magnitude of the driver's attention. The first notification mode is a notification mode in which the driver's attention is high, and is a notification by sound or voice via the speaker 16. Since the notification by sound or voice is directly transmitted to the driver's ear, the driver's attention can be strongly urged.

  The third notification mode is a notification mode in which the degree of driver's attention is weak, and is notification by overlapping icons and / or telop displays on the map data displayed on the display device 15. Since the map data is usually displayed on the display screen of the display device 15 by the display control unit 35 described above, when a relatively small icon or telop is displayed on the map data, the driver's attention is Not so strongly aroused.

  The second notification form is a notification form that has a lower degree of attention than the first notification form, but a stronger degree of attention than the third notification form, and displays a window on the display screen of the display device 15. This is a notification form. As described above, the map data is normally displayed on the display screen of the display device 15. However, a relatively large window is displayed on the display screen instead of displaying the map data or on the map data. By displaying, the driver's attention can be directed to the display screen.

  If the calculated stop score is equal to or less than a predetermined threshold value, the temporary stop guidance unit 37 indicates that the possibility of erroneous guidance is relatively low, so the notification is provided in the first and / or second notification modes. Do. On the other hand, if the calculated score is higher than the predetermined threshold value, it indicates that the possibility of erroneous guidance is relatively high, so notification is performed in the third notification form.

  Referring now to FIG. 2, examples of first to third notification modes are shown. (A) has shown the 1st alerting | reporting form, The map data around the present position of a vehicle is displayed on the display screen 51 of the display apparatus 15, the mark 53 which shows the present position of a vehicle, and driving | running | working A line 55 indicating the planned route is displayed in an overlapping manner. On the scheduled travel route 55, there is a place 57 to be temporarily stopped. Reference numeral 59 schematically indicates that notification by the speaker 16 is performed. For example, the notification is performed by transmitting a message such as “This is a temporary stop point” by voice.

  (B) has shown the 2nd alerting | reporting form, the window 61 is displayed on the display screen 51 on the display apparatus 15, and the message "It is a pause part in the future" is displayed on the window. Yes. Here, the “window” is larger than an icon or a telop described later, and in one embodiment, the “window” is displayed so as to occupy a main part of the display screen. For example, it can be displayed in the center of the display screen as shown in the figure, or can be displayed in the left half or right half of the display screen.

  When the calculated score is equal to or less than a predetermined threshold value, notification may be performed in either the first or second notification mode, or both may be combined. For example, the window (b) can be displayed and sound can be emitted through the speaker 16.

  (C) has shown the 3rd alerting | reporting form, and in this example, on the same map data as (a), the telop which described the icon 71 which shows suspension, and the character "attention of suspension!" 73 are displayed in an overlapping manner. Here, the icon and the telop are smaller in size than the window (b), and preferably, the icon and the telop are relatively corners of the display screen 51 so as not to overlap the portion where the current position of the vehicle and the planned travel route are displayed. Will be displayed. Either an icon or a telop may be displayed, or both may be displayed as shown in the figure.

  Thus, since the notification form according to the possibility of erroneous guidance for temporary stop is taken, the reliability of the driver's temporary stop function can be maintained. In addition, if the possibility of misguidement is low, a high alerting notice will be given by sound / voice or window display, so the driver is strongly alerted to the temporary stop guidance, and the driving operation for the temporary stop is performed. Can be taken promptly. On the other hand, if the possibility of erroneous guidance is high, a display with a low level of alerting by icon display or the like is performed, so that the driver can recognize that there may be a temporary stop if the display screen is viewed. it can. Even if the temporary stop guidance by the icon display etc. is wrong, the driver can quickly recognize the mistake by comparing it with the displayed map data, thus avoiding the influence on the driving operation. can do. On the other hand, if the temporary stop guidance is correct, the fact that the icon or the like has been displayed indicates that the driver has entered a branching form in which the currently traveling road may cause erroneous temporary stop guidance. Can be recognized.

  Next, with reference to FIG. 3, a situation in which erroneous guidance is likely to occur in the temporary stop guidance will be described.

  In the drawing, the road Ra branches into a road Rb and a road Rc at a branch point X, the road Rb passes over the road 101, and the road Rc intersects the road 101. Therefore, there is a sign “Stop” on the branch road Rc, and therefore there is a place to be temporarily stopped, but there is no place to be temporarily stopped on the branch road Rb.

  A dotted line indicated by reference numeral 103 indicates a route that the navigation device recognizes as the planned traveling route of the host vehicle. A solid line denoted by reference numeral 105 indicates a route on which the host vehicle has actually traveled. That is, as described above, the navigation device detects the current position of the host vehicle and maps it on the map data. However, due to an error in the detection or mapping, it is the route that the host vehicle is actually traveling. Despite being 105, it is mistakenly recognized that the vehicle is traveling on the route 103.

  For example, when the planned travel route 103 is a guidance route, the vehicle may travel on the route 105 by deviating from the guidance route 103. However, due to the above error, the navigation apparatus may erroneously recognize that the vehicle is traveling on the guidance route 103 instead of the route 105. Further, when the estimated travel route is calculated as the planned travel route, the route 105 should be determined as the estimated travel route when the vehicle travels toward the route 105 near the branch point X. May be traveling toward the route 103, and the route 103 may be estimated as the estimated travel route.

  Such misrecognition is likely to occur when the road branching form is not clear as shown in the figure. More specifically, when the branch road Ra and the branch roads Rb and Rc are connected by gentle curves, or when a plurality of branch roads are close to each other, It is not clear which branch road the vehicle has entered from the road Ra, and there is a possibility that the vehicle may be mapped to either due to the error as described above.

  Further, as described above, the navigation apparatus recognizes a road as a link connecting nodes, and the link corresponds to the center line of the road. If the width of the road is narrow, the vehicle is less likely to deviate from the center line, and therefore travel along the link recognized by the navigation device. However, if the width of the road is wide, the vehicle It is possible to travel with an angle with respect to the line (that is, travel deviating from the center line). The wider the width of the road, the larger the amount of deviation may be, so there is a risk of traveling further away from the link. Therefore, even if the map matching process is performed, the navigation device has a high possibility of erroneously recognizing a link on which the vehicle actually travels, and may erroneously recognize a branch road on which the vehicle actually enters. Get higher.

  Such misrecognition also applies when the width of the branch destination road is wide. The wider the branch destination road, the higher the possibility that the vehicle will depart from the center line (link) of the branch destination road and enter the branch destination road. Therefore, the navigation device has a high possibility of erroneously recognizing a link on which the vehicle is actually traveling, and thus has a high possibility of erroneously recognizing a branch road on which the vehicle actually enters.

  When such an erroneous recognition occurs, there is a possibility that the temporary stop guidance may also be erroneous. In the example shown in the figure, the navigation device recognizes the route 103 instead of the route 105 as the planned travel route, so it is determined that the “Stop” sign Sc exists on the planned travel route 103 and the temporary stop guidance is given. The driver will be notified. Actually, the vehicle travels on the route 105 passing through the branch road Rb, and there is no place to be temporarily stopped here. Therefore, the driver who has received such erroneous guidance feels uncomfortable.

  Therefore, in the present invention, as described above, according to the branch form of the road at the branch point (including the lane, the same shall apply hereinafter), a score representing the degree of possibility of erroneous guidance for temporary stop is calculated, The notification form of the temporary stop guidance is changed according to the score. As shown in the figure, when the road branching form is difficult to clarify, a score indicating that there is a high possibility of erroneous guidance for a temporary stop is calculated. The form, that is, the relatively strong notification form is suppressed, and the notification is performed in the relatively weak third notification form. Note that the present invention is intended to change the notification mode depending on whether or not the accuracy of the stoppage guidance is higher than a predetermined level, so in actuality, the above-described error may occur in the current position of the vehicle or the planned travel route. It should be noted that the third notification form is selected if a score indicating that the possibility of erroneous guidance is high is calculated even if is not included.

  With reference to FIG. 4, the above-described score calculation method will be described. (A) shows an example of a road branching form. In this example, an approach road Ra and branch roads Rb1, Rb2, Rb3, and Rb4 branched from the approach road Ra at a branch point X are shown. The branch road Rb4 is on an extension of the approach road Ra.

  It is assumed that the vehicle is traveling toward the branch point X on the approach road Ra as indicated by an arrow. On the branch roads Rb1 and Rb2, locations to be temporarily stopped are shown as triangle marks S1 and S2, respectively. There is no place on the branch roads Rb3 and Rb4 to be temporarily stopped.

  The score is calculated for each branch road where there is a place to be temporarily stopped. This is because, when there is a place to be temporarily stopped on the scheduled travel route, the present invention determines what is selected as the notification form of the temporary stop guidance. Therefore, in this example, a score is calculated for each of the branch roads Rb1 and Rb2. In other words, there is a possibility that erroneous guidance will occur when the planned travel route is calculated to pass through the branch road Rb1, and erroneous guidance may be generated when the planned travel route is calculated to pass through the branch road Rb2. The degree of sex is expressed as a score.

In this embodiment, the following four items are used as parameters for calculating the score of each branch road having a temporary stop place. The road data stored in the map information storage unit 12 stores not only the link representing the shape of the road as described above but also the width of the road. By referring to the road data, these road data are stored in the road data. Parameter values can be calculated. Here, the parameters α and B for the branch road Rb2 are shown in the figure.
1) Angle α between the approach road and the branch road
2) Minimum value B of the angles formed with other branch road (s) where there is no place to pause
3) Width of approach road 4) Maximum value among widths of multiple branch roads

  Further, (b) in the figure shows an example of points (points) corresponding to the values of the parameters.

  As for the above 1), the larger the angle α between the approach road Ra and the branch road, the more the approach road Ra and the branch road are connected by a gentle curve. In this case, an error is likely to occur in determining whether the vehicle is about to travel on the extension line of the approach road Ra (in this example, the branch road Rb4) at the branch point or to enter the branch road. Therefore, the larger the angle α, the higher the score value.

  Regarding the above 2), in the example of the figure, branch roads Rb3 and Rb4 exist as other branch roads where there is no place to be temporarily stopped. Therefore, when calculating the score of the branch road Rb2, B is calculated as the minimum value of the angle formed between the branch road Rb2 and the branch road Rb3 and the angle formed between the branch road Rb2 and the branch road Rb4. .

  In the example of the figure, an angle formed by the branch road Rb2 with respect to the branch road Rb3 is calculated as B. The smaller the angle B, the closer the branch road with the temporary stop place is located closer to the branch road without the temporary stop place. That is, as described with reference to FIG. 2, there is a possibility that confusion may occur between a branch road having a temporary stop place and a branch road having no temporary stop place, and erroneous guidance is likely to occur. Therefore, the smaller the B value, the higher the score value.

  Regarding 3) above, as described with reference to FIG. 3, the larger the width of the approaching road Ra, the easier the vehicle deviates from the link (center line of the road) recognized by the navigation device. This increases the possibility of erroneously recognizing the link on which the vehicle actually travels, and thus increases the possibility of an error in the planned travel route. Therefore, the greater the width of the approach route Ra, the higher the value of the score.

  The above 4) is the maximum value among the widths of the plurality of branch roads Rb1 to Rb4 in the example of the figure. For example, if the width of the branch road Rb3 is the widest among these branch roads Rb1 to Rb4, This is the maximum value to be obtained. As described with reference to FIG. 3, the greater the width of the branch road, the easier the vehicle deviates from the link (the center line of the road) recognized by the navigation device. This increases the possibility of erroneously recognizing the link being made, and thus increases the possibility of an error in the planned travel route. Therefore, the larger the maximum value obtained, the higher the score value.

  In 3) and 4) above, the number of lanes may be used instead of the width. In this case, the score is set to be higher as the number of lanes is larger. For example, in the case where one side of the approach road Ra has two lanes and in the case of three lanes, the latter is set with a higher score than the former.

  The value of the score corresponding to each parameter value as shown in (b) of the figure can be stored in advance in a storage device such as a memory as a table.

  Thus, the one-stop guidance unit 37 calculates the value of the angle α and the minimum value B based on the road data stored in the map information storage unit 12 for each branch road where there is a temporary stop, and The maximum value of the width of the road Ra and the width of the branch roads Rb1 to Rb4 is calculated, and based on these values, the corresponding score value is obtained by referring to the table. All the obtained points are added, and a score for the branch road is calculated. For example, for the branch road Rb2, if the score of 1) is 4, the score of 2) is 10, the score of 3) is 2, and the score of 4) is 2, the score of 4 + 10 + 2 + 2 = 18 is obtained. Calculated for the branch road Rb2.

  Of the scores thus calculated for each branch road, if the score for any of the branch roads exceeds a predetermined threshold, it indicates that there is a high possibility of erroneous guidance, Notification is performed in the notification form. A high score for any of the branch roads indicates that an error is likely to be included in the planned travel route calculated by the navigation device at this branch point. Therefore, in order to more reliably prevent erroneous guidance in the first and second notification modes even when the score for other branch roads is equal to or lower than the threshold value, notification is performed in the third notification mode. I do. For example, if the score of the branch road Rb2 exceeds the threshold value, the third notification mode is used even if the score of the branch road Rb1 is equal to or lower than the threshold value. On the other hand, if the scores for all the branch roads are less than or equal to the predetermined threshold value, it indicates that the possibility of erroneous guidance is low, so notification is made in the first and / or second notification modes. I do.

  In this embodiment, the score is calculated using all of the above four parameters. However, the score may be calculated using one or more of these four parameters.

  FIG. 5 shows a flowchart of a pause guidance process executed by the processing device 13 according to an embodiment of the present invention. This process can be performed repeatedly at predetermined time intervals. It is assumed that the planned travel route is calculated as described above.

  In step S11, it is determined with reference to map information whether there is a place to be temporarily stopped within a predetermined distance range from the current position of the vehicle on the planned travel route. If there is no place to pause, there is no need to notify, so the process is exited. If there is a place to be paused, the process proceeds to step S12 in order to determine whether the place is likely to cause erroneous guidance.

  In step S12, whether there is a branch point where the road where the vehicle is currently located (corresponding to the approach road Ra in FIG. 4) branches into a plurality of branch roads between the current position of the vehicle and the place to be temporarily stopped. Judge whether. If there is no branch point, it is not a place where erroneous guidance is likely to occur, so the process proceeds to step S15, and notification for prior guidance of temporary stop is performed according to the first and / or second notification modes. As described above, the first notification mode is notification by sound or voice, and the second notification mode is notification by window display.

  If there is a branch point, the process proceeds to step S13, and as described with reference to FIG. 4, the map information for each of the branch roads (the branch roads Rb1 and Rb2 in the example of FIG. 4) where there is a temporary stop place. Based on the road data stored in the storage unit 12, the values of the four parameters shown in the above 1) to 4) are calculated, and a table such as (b) in FIG. 4 is referred to based on the parameter values. Thus, the corresponding score is obtained, and the score is calculated by adding these scores.

  In step S14, it is determined whether or not the scores calculated for all the branch roads are below a predetermined threshold value. If this determination is Yes, it is not considered a branch point at which erroneous guidance is likely to occur. Therefore, in step S15, notification according to the first and / or second notification forms is performed as described above. On the other hand, if this determination is No, that is, if the score calculated for any of the branch roads exceeds the threshold value, the process proceeds to step S16, where notification according to the third notification form is performed. As described above, the third notification form is notification by displaying icons and / or telops on the map data displayed on the display screen.

  In the above-described embodiment, in step S11, the branch point is determined at predetermined time intervals in response to the determination that there is a place to be temporarily stopped within a predetermined distance (d1) from the current position of the vehicle. (S12), score calculation (S13, S14), and notification (S15 or S16) according to these results. Alternatively, when it is determined that there is a high possibility of erroneous guidance (that is, when the determination in S14 is No), the vehicle performs a notification at a predetermined distance (d2) from the temporary stop location. The process may be performed when the point is reached, and the processes of steps S12 to S14 may be repeatedly performed until the point of the predetermined distance d2 is reached. Here, d1> d2. A flowchart in this case is shown in FIG.

  Step S11 is the same as that in FIG. 5, and it is determined here whether there is a place to be temporarily stopped within the predetermined distance d1 from the current position of the vehicle on the planned travel route. Steps S12 to S14 are the same as those in FIG. However, if the determination in step S14 is No, that is, if the score of one of the branch roads exceeds the threshold, in step S21, the distance from the current position of the vehicle to the place to be paused is It is determined whether or not the distance is equal to or less than a predetermined distance d2. If this judgment is No, it indicates that the notification execution location according to the third notification form has not been reached, and the process returns to step S12. If this determination is Yes, notification according to the third notification form is performed in step S16, as in FIG.

  The significance of performing the above processing is described. As the vehicle progresses, the communication status and the road conditions around the vehicle also change. In some cases, the accuracy of evaluating the possibility of the improvement is improved. For example, although it is determined that there is a high possibility of erroneous guidance at the point where it is determined in step S11 that there is a temporary stop place (point of distance d1), the possibility of erroneous guidance is low when the vehicle further travels. It may be judged. In such a case, as shown in FIG. 5, when the notification is performed in the third notification form at the point of the distance d1, but the notification is subsequently performed in the first and / or second notification form, the driver May cause confusion. According to the form as shown in FIG. 6, until the vehicle reaches the point of the predetermined distance d2, the calculation (branch judgment and score calculation) on the possibility of erroneous guidance is repeated until the vehicle reaches the point of the distance d2. If the possibility of erroneous guidance is reduced, notification is performed in the first and / or second notification mode, and otherwise, notification is performed in the third notification mode after reaching the point of the distance d2. Therefore, it is possible to provide the driver with temporary stop guidance with better accuracy.

  As described above, the score for the branch point is a value determined according to the branching form of the approach road and the branch road. Therefore, in another embodiment of the present invention, the map information is calculated so that a score is calculated in advance for each branch point, and the score is associated with the branch point in the map information, for example, included in the attribute information of the road data. The data can be stored in the storage unit 12 in advance. In this case, in response to the determination that a branch point exists, the temporary stop guide unit 37 in FIG. 1 reads the score stored corresponding to the branch point from the map information storage unit 12 and uses the score thus read out as the read score. Based on this, the notification form is determined as described above.

  FIG. 7 shows a flowchart of the temporary stop guidance process in this embodiment. The difference from FIG. 5 is that step S31 is performed instead of step S13. That is, in step S31, the score stored for the branch point determined in step S12 is read from the map information. Here, when there are a plurality of branch roads having a place to be temporarily stopped, a plurality of scores are read out. In step S14, it is determined whether or not the score for all the read roads is equal to or less than a predetermined threshold value. If this determination is Yes, as described above, in step S15, notification according to the first and / or second notification form is performed. On the other hand, if this determination is No, that is, if the score read for any of the branch roads exceeds the threshold value, the process proceeds to step S16 to perform notification according to the third notification form.

  In addition, you may combine the form of FIG. 6 and the form of FIG. In this case, the determination of the branch point in step S12 and the reading of the score in step S31 are repeated until the vehicle reaches a point of the predetermined distance d2 from the temporary stop place. If the determination in step S14 becomes Yes before reaching the point of the predetermined distance d2, the notification of step S15 is performed, otherwise, the notification of step S16 is performed when the point of the predetermined distance d2 is reached. Is called. If the determination of the branch point in step S12 is constant, since the score is associated with the branch point in advance, the determination result in step S14 does not change, but as the vehicle advances, the determination result of the branch point changes. It can also happen. By combining the forms of FIG. 6 and FIG. 7, even when such a change occurs, an appropriate notification form can be realized.

  Alternatively, instead of storing a score in association with a branch point of map information, data indicating a notification form corresponding to the score may be stored in association with each other. For example, any one of the first to third notification forms can be stored in association with each branch point. In this case, in response to the determination that the branch point exists as described above, the processing device 13 refers to the notification form data stored corresponding to the branch point, and notifies the suspension according to the notification form. It can be performed.

  Since it may take time to calculate and store the scores for all the branch points in advance, when the real-time score calculation is performed once as described with reference to FIG. You may make it memorize | store a score or the alerting | reporting form according to this score corresponding to the branch point. Thereafter, when passing through the branch point, the stop guidance is notified according to the stored score or data indicating the notification form.

  As described above, specific embodiments of the present invention have been described. However, the present invention is not limited to these embodiments.

DESCRIPTION OF SYMBOLS 11 Current position detection part 12 Map information storage part 13 Processing apparatus

Claims (8)

Means for detecting the current position of the vehicle;
Means for calculating, on the map data, a route traveled by the vehicle as a planned travel route based on the detected current position;
Means for determining, based on the map data, whether there is a place to be temporarily stopped on the planned travel route of the vehicle;
In the case where it is determined that there is a place to be temporarily stopped, a notification means for notifying a driver of the vehicle of a stop guidance prior to the vehicle reaching the position to be temporarily stopped; A navigation device mounted on the vehicle, comprising:
When it is determined that there is a place to be temporarily stopped, a branch point where the road where the vehicle is currently located branches into a plurality of branch roads exists between the current position and the place to be temporarily stopped Branch determination means for determining whether to
If it is determined that the branch point exists, among each of the plurality of branch roads where there is a place to be temporarily stopped, between the branch road and the road where the vehicle is currently located An angle, a minimum value of an angle of the branch road with respect to the one or more branch roads where the place to be temporarily stopped does not exist, a width of the road where the vehicle is currently located, and the branch road And a score calculation means for calculating a score indicating the degree of possibility that the guidance about the place to be temporarily stopped becomes a false guidance based on at least one of the largest widths,
The notification means changes the notification form of the temporary stop guidance according to the calculated grade size.
Navigation device. The informing means is that the score calculated for all the branch roads among the branch roads where the place to be temporarily stopped is less than or equal to a threshold value indicating that there is a high possibility of being the erroneous guidance. In some cases, the suspension guidance is notified via at least one of notification by sound or voice and notification by window display on the display screen of the display device.
The navigation device according to claim 1. The notification means has a threshold value indicating that the score calculated for any of the branch roads where the place to be temporarily stopped is likely to be the erroneous guidance is high. If it exceeds, on the map data displayed on the display device, through the display of at least one of the icon and the telop, notification of the temporary stop guidance,
The navigation device according to claim 1 or 2. When the score calculated for any of the branch roads where the place to be temporarily stopped exceeds a threshold value indicating that the possibility of erroneous guidance is high Until the current position of the vehicle reaches a predetermined distance with respect to the place to be temporarily stopped, the processing by the branch determination means and the score calculation means is repeated.
The navigation device according to any one of claims 1 to 3. Means for detecting the current position of the vehicle;
Means for calculating, on the map data, a route traveled by the vehicle as a planned travel route based on the detected current position;
Means for determining, based on the map data, whether there is a place to be temporarily stopped on the planned travel route of the vehicle;
In the case where it is determined that there is a place to be temporarily stopped, a notification means for notifying a driver of the vehicle of a stop guidance prior to the vehicle reaching the position to be temporarily stopped; A navigation device mounted on the vehicle, comprising:
When it is determined that there is a place to be temporarily stopped, a branch point where the road where the vehicle is currently located branches into a plurality of branch roads exists between the current position and the place to be temporarily stopped Branch determination means for determining whether to
Of each of the plurality of branch roads at the branch point, for each branch road where there is a place to be temporarily stopped, an angle between the branch road and the road where the vehicle is currently located, A minimum value of angles with respect to one or a plurality of branch roads where the place to be temporarily stopped does not exist, a width of a road where the vehicle is currently located, and a maximum width of the plurality of branch roads, Based on at least one, a score indicating the degree of possibility that the guidance about the place to be paused may be erroneous guidance is calculated in advance, and the score is stored in association with the branch point on the map data Storage means;
If the branch determining means determines that the branch point exists, the score reading means reads the score stored in association with the branch point, and
The notification means changes the notification form of the pause guidance according to the size of the read score.
Navigation device. The notification means is less than a threshold value indicating that the score read for all branch roads among the branch roads where the place to be temporarily stopped is high is likely to be the erroneous guidance If it is, the notification of the temporary stop guidance is performed via at least one of notification by sound or voice and notification by window display on the display screen of the display device.
The navigation device according to claim 5. The notification means is a threshold value indicating that the score read for any of the branch roads where the place to be temporarily stopped is likely to be the erroneous guidance. If it exceeds, on the map data displayed on the display device, through the display of at least one of the icon and the telop, notification of the pause guidance,
The navigation device according to claim 5 or 6. When the score read for any branch road among the branch roads where the place to be temporarily stopped exceeds a threshold value indicating that the possibility of erroneous guidance is high Until the current position of the vehicle reaches a point a predetermined distance from the place to be temporarily stopped, the processing by the branch determination means and the score reading means is repeated.
The navigation device according to any one of claims 5 to 7.

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