JP2009162518A - Navigation apparatus and navigation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation apparatus, or the like capable of guiding a user more appropriately by searching a route preferentially passing a road capable of precisely locating the position of an own vehicle. <P>SOLUTION: The navigation apparatus 1 has a route search means 19 for searching a route from a departing position to a destination, based on road information R indicating a road network according to the connection relationship of a plurality of road links. In the navigation apparatus 1, the route search means 19 has a precise priority route search function for setting the link costs of a road link that may precisely locate the position of an own vehicle relatively smaller than those of other road links, when searching a route so that the total costs of the entire route are minimized based on the link costs set to each road link. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is used in a navigation device having a route search function for searching for a route from a departure place to a destination based on road information representing a road network based on a connection relationship of a plurality of road links, and such a navigation device. Regarding navigation programs.

  Regarding a route search function for searching for a route from a departure place to a destination based on road information representing a road network based on a connection relationship of a plurality of road links, for example, the following Patent Document 1 discloses the following navigation device technology: Is disclosed. This navigation device is configured to select one of a recommended route search, a distance priority search, a toll road priority search, a general road priority search, and a vehicle speed / traffic volume priority search as a route search condition. Here, the recommended route search is a search condition for searching for a route in which the total from the starting point to the destination of the link cost set based on the link length, width, road type, etc. of each road link is minimized. The distance priority search is a search condition in which a route with a short distance from the departure point to the destination is prioritized. The toll road priority search is a search condition in which priority is given to including a toll road such as an expressway in the route. The general road priority search is a search condition in which priority is given to including a general road in a route. Vehicle speed / traffic volume priority search is a search condition that prioritizes routes with high vehicle speed, low traffic volume, and short travel time.

Japanese Unexamined Patent Publication No. 2003-214868 (page 6, FIG. 5)

  By the way, as an essential function of the navigation device, there is a route guidance function that guides the user of the host vehicle to the destination according to the optimum route from the departure place to the set destination. Such route guidance displays the position of the vehicle on a map, and the route of the vehicle is determined based on the route searched in advance based on road information and the current position of the vehicle acquired from a GPS signal or the like. This is realized by performing route guidance when a predetermined distance is reached to the point where the change is made. Therefore, the higher the accuracy of the information indicating the current position of the host vehicle, that is, the more accurately the position and travel lane of the host vehicle can be specified, the more appropriate the timing is appropriate for the user. It becomes possible to guide the contents. Such appropriate guidance is particularly useful when performing route guidance to a destination that has never been performed by the user.

  And the precision of the information showing the present position of such a own vehicle may change with the path | routes which the own vehicle drive | works. That is, for example, information that can be used to specify the position of the vehicle in the traveling direction and the traveling lane with high accuracy, such as an optical beacon or a radio beacon emitted from a facility installed on the road to the vehicle. When a road that can be acquired is used as a route, the position of the host vehicle can be specified with higher accuracy than when a road that cannot acquire such information is used as a route. If the position of the host vehicle can be specified with high accuracy, as described above, it is possible to guide the user with appropriate content at a more appropriate timing. However, some of the route search conditions that have been used so far are to search for routes according to conditions related to time, distance, cost, etc., but in order to guide the appropriate contents at a more appropriate timing, There has been no technology that preferentially searches for a route that can identify the position of the vehicle with high accuracy.

  The present invention has been made in view of the above-described problems, and the object thereof is to enable searching for a route that preferentially passes through a road capable of specifying the vehicle position with high accuracy. Accordingly, it is an object of the present invention to provide a navigation device and a navigation program capable of providing more appropriate guidance to the user.

  A feature of a navigation device comprising route search means for searching for a route from a departure point to a destination based on road information representing a road network by a connection relation of a plurality of road links according to the present invention for achieving the above object In the configuration, when the route search means performs a route search so that the total cost of the entire route is minimized based on the link cost set for each road link, the position of the host vehicle is accurately determined. The high-priority priority route search function is provided that sets the link cost of a road link that may be specified relatively smaller than other road links.

  According to this feature configuration, the link cost of a road link that may be able to specify the position of the host vehicle with high accuracy is set relatively smaller than other road links, and the total cost of the entire route is minimized. The route search can be performed as follows. Therefore, it is possible to search for a route that preferentially passes through a road that can specify the vehicle position with high accuracy. As a result, it is possible to provide guidance to the user with appropriate content at a more appropriate timing, which can contribute to safe driving of the vehicle and provide the user with a sense of security through appropriate guidance. Can also be given.

  Here, when the route search means executes the high-accuracy priority route search function, there is no possibility that a value set for a road link that may be able to specify the position of the host vehicle with high accuracy. Using a high-precision correction coefficient smaller than the value set for the road link and multiplying the basic link cost preset for each road link by the high-precision correction coefficient, a route search is performed using the link cost. It is preferable to adopt a configuration for performing the above.

  According to this configuration, while reflecting the value of the basic link cost set in advance for each road link, the link cost of the road link that may be able to identify the position of the vehicle with high accuracy is the same as the basic link cost. It becomes possible to set smaller than the link cost of the other road link which has a value. Therefore, it is possible to search for a route that preferentially passes through a road that can specify the vehicle position with high accuracy.

  In addition, the high-accuracy correction coefficient may specify a value set for a road link that may be able to specify the position of the traveling direction of the host vehicle with high accuracy and a traveling lane of the host vehicle with high accuracy. It is preferable that a value set for the road link and a value set for the road link that may be able to specify both the position in the traveling direction of the host vehicle and the traveling lane with high accuracy are preferably determined in advance. .

  According to this configuration, an appropriate high-accuracy correction is performed depending on whether the road link that may be able to specify the position of the own vehicle with high accuracy can specifically specify the own vehicle position in which direction. A coefficient can be set. Therefore, it is possible to set the link cost after correction with the high accuracy correction coefficient more appropriately.

  In addition, it is preferable that the high-accuracy correction coefficient is determined in advance for each road link in accordance with the possibility that the position of the host vehicle can be specified with high accuracy when traveling on each road link.

  According to this configuration, by setting an appropriate high-accuracy correction coefficient individually for each road link, it is possible to more appropriately set the link cost after correction using the high-accuracy correction coefficient.

  In addition, it is preferable that the high-accuracy correction coefficient is set to be a smaller value as the possibility that the position of the host vehicle can be identified with high accuracy increases.

  According to this configuration, the link cost after correction by the high-precision correction coefficient can be reduced as the possibility that the position of the host vehicle can be specified with high accuracy increases. Therefore, it is possible to search for a route that preferentially passes on a road that has a high possibility of specifying the position of the host vehicle with high accuracy.

  The basic link cost is preferably set according to the road length and road attribute of each road link.

  According to this configuration, a route search can be performed using an appropriate basic link cost set in accordance with the road length of each road link and road attributes such as speed limit, number of lanes, road type, and the like. Therefore, it is also possible to appropriately search for a route that preferentially passes through a road capable of specifying the vehicle position with high accuracy.

  In addition, when the route search means executes the high-accuracy priority route search function, a value that is set to a road link that may be able to specify the position of the host vehicle with high accuracy is a road that does not have that possibility. Using a high-precision correction coefficient larger than the value set for the link, the result of subtracting the high-precision correction coefficient from the basic link cost preset for each road link, or the position of the host vehicle can be specified with high accuracy. The high accuracy is set to the basic link cost set in advance for each road link by using a high accuracy correction coefficient in which the value set for the potential road link is smaller than the value set for the road link without the possibility. A configuration in which a route search is performed using the result of adding the correction coefficient as the link cost is also preferable.

  According to this configuration, while reflecting the value of the basic link cost set in advance for each road link, the link cost of the road link that may be able to identify the position of the vehicle with high accuracy is the same as the basic link cost. It becomes possible to set smaller than the link cost of the other road link which has a value. Therefore, it is possible to search for a route that preferentially passes through a road that can specify the vehicle position with high accuracy.

  Alternatively, the route search means, when executing the high-accuracy priority route search function, for a road link that may be able to specify the position of the host vehicle with high accuracy, a basic link cost preset for each road link. It is also suitable as a configuration in which a route search is performed using a high-accuracy priority link cost set to a smaller value as the link cost.

  According to this configuration, when the high-accuracy priority route search function is executed, a road capable of specifying the vehicle position with high accuracy by using a preset high-accuracy priority link cost as the link cost. It is possible to appropriately search for a route that preferentially passes through.

  In addition, referring to a feature database storing feature information including position information and attribute information of the feature, the image recognition result of the feature included in the image information obtained by photographing the periphery of the own vehicle and the feature information It further comprises own vehicle position specifying means for collating and specifying the position of the own vehicle with high accuracy, and based on the feature information stored in the feature database, the traveling direction of the own vehicle by the own vehicle position specifying means. There is a possibility that the position of the own vehicle can be specified with high accuracy on a road link where one or both of the feature that can be used for specifying the position and the feature that can be used for specifying the traveling lane of the own vehicle exists. A certain road link is preferable.

  According to this configuration, the position of the own vehicle is specified with high accuracy by comparing the image recognition result of the feature included in the image information obtained by photographing the periphery of the own vehicle with the feature information stored in the feature database. In the case where the vehicle position specifying means is provided, a road link that can specify the position of the vehicle with high accuracy can be appropriately set. Therefore, it is possible to appropriately search for a route that preferentially passes through a road capable of specifying the vehicle position with high accuracy.

  Further, the information receiving means for receiving from the outside of the host vehicle specific information that can be used to specify one or both of the position in the traveling direction of the host vehicle and the traveling lane of the host vehicle is further received. It is preferable that the road link is a road link that can identify the position of the host vehicle with high accuracy.

  According to this configuration, in the case of including the information receiving means for receiving from the outside of the own vehicle specific information that can be used to specify one or both of the position in the traveling direction of the own vehicle and the traveling lane of the own vehicle, It is possible to appropriately set a road link that may identify the position of Therefore, it is possible to appropriately search for a route that preferentially passes through a road capable of specifying the vehicle position with high accuracy.

  Preferably, the route search means is configured to perform a route search based on a node cost set for each intersection node in addition to the link cost so that the total cost of the entire route is minimized. It is.

  According to this configuration, it is possible to perform a route search more appropriately in consideration of the node cost set for each intersection node in addition to the link cost.

  In addition to the high-precision priority route search function, the route search means includes one or two or more route search functions that perform route search under conditions different from the high-precision priority route search function. A configuration is preferable.

  According to this configuration, the user of the navigation device can selectively use the high-precision priority route search function and other route search functions as needed. Therefore, the convenience for the user can be further improved.

  A characteristic configuration of the navigation program according to the present invention is a route search function for searching a route from a departure place to a destination based on road information representing a road network by a connection relation of a plurality of road links, When performing a route search so that the total cost of the entire route is minimized based on the set link cost, the link cost of the road link that may be able to identify the position of the host vehicle with high accuracy. This is to make the computer realize a high-precision priority route search function that is set to be relatively smaller than the road link.

  According to this feature configuration, the link cost of a road link that may be able to specify the position of the host vehicle with high accuracy is set relatively smaller than other road links, and the total cost of the entire route is minimized. The route search can be performed as follows. Therefore, it is possible to search for a route that preferentially passes through a road that can specify the vehicle position with high accuracy. As a result, it is possible to provide guidance to the user with appropriate content at a more appropriate timing, which can contribute to safe driving of the vehicle and provide the user with a sense of security through appropriate guidance. Can also be given.

  Next, a navigation device 1 according to an embodiment of the present invention will be described based on the drawings. FIG. 1 is a block diagram showing a schematic configuration of a navigation device 1 according to the present embodiment. Moreover, FIG. 2 is a figure which shows the own vehicle C by which this navigation apparatus 1 is mounted. The navigation device 1 searches for a route from a departure place to a destination based on road information R representing a road network based on a connection relationship of a plurality of road links, and provides guidance for traveling along the route to a user ( To the driver of the vehicle C). With regard to this route search, the navigation device 1 is provided with a selectable three route search functions including a high-precision priority route search function, a recommended route search function, and a distance priority search function. In the present embodiment, the navigation device 1 collates the image recognition result of the feature included in the image information G obtained by photographing the periphery of the host vehicle C with the feature information F stored in the feature database DB2. Thus, a function of specifying the position of the traveling direction of the host vehicle C with high accuracy and a function of specifying the traveling lane of the host vehicle C are provided. The high-accuracy priority route search function is a route search function that searches for a route that preferentially passes a road that allows the position of the host vehicle C to be specified with high accuracy.

  Each function part of the navigation apparatus 1 shown in FIG. 1, specifically, the image information acquisition part 12, the own vehicle position information acquisition part 13, the display process part 17, the map matching process part 18, the route search process part 19, guidance processing The unit 21, the search processing unit 22, the image recognition unit 23, the external information reception unit 24, the vehicle position correction unit 25, and the travel lane identification unit 26 are each a common processing unit such as an independent CPU or the like. As described above, a functional unit for performing various processes on input data is implemented by hardware or software (program) or both. Each of these functional units is configured to exchange information with each other. Further, the map database DB1 and the feature database DB2 are, for example, a recording medium capable of storing information, such as a hard disk drive, a DVD drive equipped with a DVD-ROM, a CD drive equipped with a CD-ROM, and a driving means thereof. Is provided as a hardware configuration. Hereinafter, the configuration of each part of the navigation device 1 according to the present embodiment will be described in detail.

1. Map database The map database DB1 is a database in which map information M divided into predetermined sections is stored. FIG. 3 is a diagram illustrating an example of the configuration of the map information M stored in the map database DB1. As shown in this figure, the map information M includes road information R representing a road network by a connection relation of a plurality of road links k. The road network includes a road link k and an intersection node n corresponding to a connection point between the two road links k. The intersection node n corresponds to an intersection on an actual road, and the road link k corresponds to a road connecting the intersections. Each intersection node n has information on the position (coordinates) on the map expressed by latitude and longitude. Each road link k has information such as a basic link cost CL, a road length, a road type, a road width, the number of lanes, and a shape interpolation point for expressing a link shape as link attribute information. Here, the basic link cost CL is a link cost set in advance for each road link in accordance with road attributes such as road length and road type, and is information used in route search. The road type is information on the road type when the road is divided into a plurality of types such as an expressway, a national road, a prefectural road, a general road, a narrow street, and an introduction road. The intersection node n has information such as the node cost CN, traffic restrictions, and presence / absence of signals as node attribute information. In FIG. 3, only the road information R of one section is illustrated, and the road information R of other sections is omitted. The basic link cost CL and the node cost CN will be described later in detail.

  This road information R is used for map matching described later, route search from the departure point to the destination, route guidance to the destination, and the like. Although illustration is omitted, in addition to such road information R, the map information M includes drawing information having various information necessary for displaying the map, intersection information composed of detailed information on the intersection, and the like. ing. In addition, the drawing information includes background information necessary for displaying road shapes, buildings, rivers, and the like, and character information necessary for displaying city names, road names, and the like.

2. Feature database The feature database DB2 is a database in which information on various features provided on or around the road, that is, feature information F is stored. Features for which feature information F is stored in the feature database DB2 include road markings (paint markings) provided on the road surface. FIG. 4 is a diagram illustrating an example of the feature information F of the road marking stored in the feature database DB2. Examples of features related to such road markings include, for example, pedestrian crossings, stop lines, speed markings indicating maximum speed, zebra zones, lane markings that divide each lane along the road (solid lines, broken lines, double lines) , Etc.), and traffic direction markings (including arrow markings, for example, straight arrows, right-turn arrows, etc.) that specify the traveling direction of each lane. In addition to such road markings, the features in which the feature information F is stored can include various features such as traffic lights, signs, overpasses, tunnels, and manholes.

  Further, the feature information F includes, as its contents, position information of each feature and feature attribute information associated therewith. Here, the position information includes information on the position (coordinates) on the map of the representative point of each feature associated with the road link k or the intersection node n constituting the road information R, and the direction of each feature. Yes. In this example, the representative point is set near the center in the length direction and width direction of each feature. The feature attribute information includes identification information (feature ID) for identifying each feature from other features, type information indicating the feature type of each feature, or the shape, size, and color of the feature. The feature form information such as is included. Here, the feature type specifically indicates the type of feature having basically the same form such as “pedestrian crossing”, “stop line”, “speed indication (30 km / hour)”, and the like. Information.

3. Input / Output Device The display input device 27 is a device in which a display device and an input device are integrated. As the display device, for example, various known display devices such as a liquid crystal display, a plasma display, an organic EL (electroluminescence) display, a field emission display, and a CRT (cathode-ray tube) display can be used. Examples of the input device include a touch panel disposed on the display screen of the display device and an operation switch disposed beside the display screen. The audio output device 28 includes a speaker, an amplifier, and the like.

4). Image Information Acquisition Unit The image information acquisition unit 12 functions as an image information acquisition unit that acquires image information G obtained by photographing the periphery of the host vehicle C with the imaging device 11. Here, the imaging device 11 is an in-vehicle camera or the like provided with an imaging element, and is provided at a position where at least a road surface of the road around the host vehicle C can be imaged. As such an imaging device 11, for example, it is preferable to use a back camera that images the road surface behind the host vehicle C as shown in FIG. The image information acquisition unit 12 captures imaging information captured by the imaging device 11 at predetermined time intervals via a frame memory (not shown) or the like. The time interval for capturing the image information G at this time can be set to, for example, about 10 to 50 ms. Thereby, the image information acquisition unit 12 can continuously acquire the image information G of a plurality of frames captured by the imaging device 11. The acquired image information G is output to the image recognition unit 23.

5. Own vehicle position information acquisition unit The own vehicle position information acquisition unit 13 functions as own vehicle position information acquisition means for acquiring own vehicle position information P representing the current position of the own vehicle C. Here, the vehicle position information acquisition unit 13 is connected to the GPS receiver 14, the direction sensor 15, and the distance sensor 16. Here, the GPS receiver 14 is a device that receives a GPS signal from a GPS (Global Positioning System) satellite. This GPS signal is normally received every second and output to the vehicle position information acquisition unit 13. The own vehicle position information acquisition unit 13 analyzes signals from GPS satellites received by the GPS receiver 14 and acquires information such as the current position (latitude and longitude), traveling direction, and moving speed of the own vehicle C. Can do. The direction sensor 15 is a sensor that detects the traveling direction of the host vehicle C or a change in the traveling direction. The azimuth sensor 15 includes, for example, a gyro sensor, a geomagnetic sensor, an optical rotation sensor attached to the rotating part of the handle, a rotary resistance volume, an angle sensor attached to the wheel part, and the like. Then, the direction sensor 15 outputs the detection result to the vehicle position information acquisition unit 13. The distance sensor 16 is a sensor that detects the vehicle speed and the moving distance of the host vehicle C. The distance sensor 16 is, for example, a vehicle speed pulse sensor that outputs a pulse signal each time a vehicle drive shaft or wheel rotates a certain amount, a yaw / G sensor that detects the acceleration of the host vehicle C, and an integrated detected acceleration. Configured by a circuit or the like. Then, the distance sensor 16 outputs information on the vehicle speed and movement distance as the detection result to the vehicle position information acquisition unit 13.

  And the own vehicle position information acquisition part 13 performs the calculation which pinpoints the position of the own vehicle C by a well-known method based on the output from these GPS receiver 14, the direction sensor 15, and the distance sensor 16. FIG. The vehicle position information P acquired in this way is information including an error due to the detection accuracy of each of the sensors 14 to 16. In addition, the vehicle position information P acquired in this way is information that specifies up to the travel lane in which the host vehicle C is traveling when the road on which the host vehicle C is traveling has a plurality of lanes. It is not. Therefore, in the present embodiment, as described later, the map matching processing unit 18 performs correction so that the position of the host vehicle C indicated by the host vehicle position information P is on the road indicated by the map information M. The own vehicle position correcting unit 25 corrects the position of the own vehicle C in the traveling direction indicated by the own vehicle position information P using the image information G and the feature information F. Further, the traveling lane identifying unit 26 identifies the traveling lane of the host vehicle C. Thereby, the own vehicle position information acquisition part 13 acquires the highly accurate own vehicle position information P including the information of the traveling lane of the own vehicle C.

6). Image Recognition Unit The image recognition unit 23 functions as an image recognition unit that performs image recognition processing on the image information G acquired by the image information acquisition unit 12. In other words, the image recognition unit 23 performs image recognition processing of features included in the image information G obtained by photographing the periphery of the host vehicle C by the imaging device 11. At this time, the image recognition unit 23 performs image recognition processing using the feature information F stored in the feature database DB2. Specifically, the image recognizing unit 23 sets a feature to be included in an imaging region by the imaging device 11 based on the own vehicle position information P as a target feature, and uses the feature information F of the target feature as a feature. Obtained from the property database DB2. Then, the image recognition unit 23 performs binarization processing, edge detection processing, and the like on the image information G acquired by the image information acquisition unit 12, and features (road markings) included in the image information G The contour information is extracted. After that, the image recognition unit 23 compares the extracted contour information of the feature with the form information included in the feature information F of the target feature acquired from the feature database DB2, and determines whether or not they match. Determine. When the contour information of the feature and the form information included in the feature information F of the target feature match, it is determined that the image recognition of the target feature has succeeded, and the image recognition result is determined as the vehicle position correction unit. To 25. If the image recognition of the target feature fails, the image recognition result is not output to the vehicle position correction unit 25, and therefore the vehicle position information P is not corrected by the vehicle position correction unit 25. .

  The image recognizing unit 23 also identifies a section around the vehicle position on the road on which the vehicle C stored in the feature database DB2 is stored in order to identify the vehicle lane of the vehicle C in the vehicle lane identifying unit 26. Using the line feature information F, image recognition of lane markings around the host vehicle C is performed. Specifically, the image recognizing unit 23 sets a lane marking to be included in the imaging area by the imaging device 11 based on the vehicle position information P as the target feature, and uses the feature information F of the target feature as the ground. Obtained from the property database DB2. Then, the image recognition unit 23 performs binarization processing, edge detection processing, and the like on the image information G acquired by the image information acquisition unit 12, and features (road markings) included in the image information G The contour information is extracted. Thereafter, the image recognizing unit 23 determines the lane markings around the host vehicle C based on the extracted contour information of the features and the form information included in the lane marking feature information F acquired from the feature database DB2. The position and the type of lane marking are recognized. Then, the image recognition unit 23 outputs the image recognition result of such lane markings to the travel lane specifying unit 26.

7). External Information Receiving Unit The external information receiving unit 24 functions as information receiving means for receiving specific information that can be used for specifying the position of the host vehicle C from the outside of the host vehicle C. Such specific information includes, for example, information from VICS (Vehicle Information and Communication System), specifically, optical beacons and radio wave beacons from transmitters provided on each lane of the road. There is information from. These pieces of information include information that can specify the lane in which the transmitter is installed. The information received by the external information receiving unit 24 is sent to a travel lane specifying unit 26 described later and used for specifying the travel lane of the host vehicle C.

8). Self-vehicle position information correction unit The self-vehicle position correction unit 25 is based on the result of the image recognition processing by the image recognition unit 23 and the position information of the target feature included in the feature information F acquired from the feature database DB2. This is vehicle position information correction means for correcting the vehicle position information P. In the present embodiment, the host vehicle position correction unit 25 moves in the traveling direction of the host vehicle C based on the result of the image recognition processing by the image recognition unit 23 and the position information of the target feature included in the feature information F. Along with this, the vehicle position information P is corrected. Specifically, the own vehicle position correction unit 25 first includes an image of the target feature based on the image recognition result by the image recognition unit 23 and the mounting position, mounting angle, and angle of view of the imaging device 11. The positional relationship between the host vehicle C and the target feature when the image information G is acquired is calculated. For example, when the image information G is acquired in the situation illustrated in FIG. 5, the own vehicle position correction unit 25 determines the position of the own vehicle C and the crosswalk as the target feature ft based on the image recognition result of the image information G. A relationship (for example, distance d) is calculated. Next, the own vehicle position correcting unit 25 calculates the positional relationship between the own vehicle C and the target feature ft, and the position information of the target feature included in the feature information F acquired from the feature database DB2. Based on this, the position information of the subject vehicle ft in the traveling direction of the subject vehicle C (feature information F) is calculated and acquired with high accuracy. And the own vehicle position correction | amendment part 25 is contained in the own vehicle position information P acquired by the own vehicle position information acquisition part 13 based on the highly accurate position information of the own vehicle C acquired in this way. The information on the current position in the traveling direction of C is corrected. As a result, the host vehicle position information acquisition unit 13 acquires the corrected host vehicle position information P with high accuracy. Therefore, in the present embodiment, the vehicle position correction unit 25 and the vehicle position information acquisition unit 13 perform the image recognition result and the feature information F of the feature included in the image information G obtained by photographing the periphery of the vehicle C. And the vehicle position specifying means 29 for specifying the position of the vehicle C with high accuracy.

9. Traveling Lane Identification Unit The traveling lane identification unit 26 functions as a traveling lane identification unit that identifies the traveling lane of the host vehicle C. Here, the traveling lane identifying unit 26 performs processing for identifying the traveling lane of the host vehicle C based on the result of the image recognition processing by the image recognizing unit 23 and the feature information F acquired from the feature database DB2. For this purpose, the traveling lane specifying unit 26 is stored in the feature database DB2 and the image recognition result by the image recognition unit 23 of the image of the lane marking included in the image information G acquired by the image information acquisition unit 12, for example. The feature information F of the lane marking around the vehicle position on the road on which the vehicle C is traveling is used. Specifically, the traveling lane specifying unit 26 includes the types of lane lines (line types such as solid lines, broken lines, and double lines) and arrangement around the host vehicle C indicated in the image recognition result by the image recognition unit 23; Based on the form information included in the feature information F of the lane marking around the own vehicle position, the traveling lane of the own vehicle C is specified. For example, when the image information G as shown in FIG. 6 is acquired and the feature information F around the host vehicle C as shown in FIG. 7 is acquired, the lane in which the host vehicle C is traveling is obtained. Can be identified as the center lane of the three lanes. That is, in the image shown in the image information G shown in FIG. 6, there are broken lane markings on both sides with respect to the center in the width direction of the image, which is the position of the host vehicle C, and solid lane markings on both outer sides. There is. On the other hand, according to the feature information F shown in FIG. 7, the road on which the vehicle C is traveling has three lanes, and the feature information F of the solid line is present on both sides in the width direction of the road. It can be seen that the feature information F of the broken lane markings that divide each lane exists at the center in the width direction of the road. Therefore, the traveling lane identification unit 26 can identify that the traveling lane of the host vehicle C is the central lane among the three lanes by comparing these pieces of information.

  Even when the number of road lanes is 4 or more, as shown in FIG. 8, for example, if the combination of the types of lane markings on both sides of each lane is different from each other, the lane markings included in the image information G The driving lane of the host vehicle C can be identified by comparing the image recognition result of the above and the feature information F of the lane marking (target feature ft) acquired from the feature database DB2. For example, as shown in FIG. 9, even if there are a plurality of lanes having the same combination of the types of lane markings on both sides, there are different types and forms of features (target features ft) in each lane. In this case, the traveling lane of the host vehicle C can be specified. In the example of FIG. 9, each lane is provided with features of different traffic direction markings in different traveling directions. Therefore, the image recognition is performed by comparing the feature information F of these features (target feature ft) acquired from the feature database DB2 with the image recognition result of the lane marking included in the image information G. The lane in which the feature that matches the feature is provided can be specified as the traveling lane of the host vehicle C.

  The traveling lane specifying unit 26 determines whether or not the lane has been changed based on whether or not the own vehicle C has crossed the lane line based on the position information of the lane line indicated in the image recognition result by the image recognition unit 23. The traveling lane of the vehicle C is specified. The traveling lane specifying unit 26 selects a lane only when it is necessary to identify the traveling lane of the host vehicle C, that is, when the road on which the host vehicle C is traveling has a plurality of lanes in the traveling direction (one side). Perform the specified operation. Then, the travel lane identification unit 26 sends information for identifying the travel lane of the host vehicle C to the host vehicle position information acquisition unit 13. Thereby, the own vehicle position information acquisition part 13 produces | generates the own vehicle position information P containing the information of the driving lane of the own vehicle C as mentioned above. Therefore, in the present embodiment, the traveling lane specifying unit 26 functions as the own vehicle position specifying unit 29 together with the own vehicle position correcting unit 25 and the own vehicle position information acquiring unit 13.

10. Processing Unit for Realizing Navigation Function This navigation device 1 includes a display processing unit 17, a map matching processing unit 18, a route search processing unit 19, a guidance as a navigation calculation processing unit for realizing a basic navigation function. A processing unit 21 and a search processing unit 22 are provided. Here, the display processing unit 17 performs a calculation process for displaying a map of the surroundings of the vehicle position, the destination, etc. on the display screen of the display input device 27, or displaying the vehicle position on the map. It is. The map matching processing unit 18 causes the vehicle position indicated by the vehicle position information P acquired by the vehicle position information acquisition unit 13 to be on a road included in the road information R stored in the map database DB1. A processing unit for performing map matching processing for correcting the vehicle position information P. The route search processing unit 19 is a processing unit that performs arithmetic processing for searching for a guidance route from a departure place such as the vehicle position to a destination input by the display input device 27, for example. The present application is characterized by route search processing by the route search processing unit 19. Therefore, this point will be described in detail later. The guidance processing unit 21 provides the user with guidance display on the display screen of the display input device 27 and voice guidance by the voice output device 28 according to the route from the departure place to the destination searched by the route search processing unit 19. And a processing unit that performs arithmetic processing for performing appropriate route guidance. The search processing unit 22 is a processing unit that performs arithmetic processing for searching for destinations, points for map display, and the like based on addresses, telephone numbers, facility names, genres, and the like.

11. Function of Route Search Processing Unit Next, the function of the route search processing unit 19 which is a characteristic configuration of the present invention will be described in detail. The route search processing unit 19 functions as route search means for searching for a route from the departure point to the destination based on the road information R representing the road network by the connection relationship of the plurality of road links k. In the present embodiment, the route search processing unit 19 includes a plurality of route search functions that perform route search under different conditions. Therefore, in the navigation device 1, for example, when the current position of the host vehicle C indicated in the host vehicle position information P is set as the departure point and the destination is input by the user using the display input device 27, a plurality of these The route search function is displayed on the display input device 27 in a selectable manner. FIG. 10 is a diagram illustrating an example of a search function selection screen that is a display screen that displays a plurality of such route search functions in a selectable manner. As shown in this figure, in the present embodiment, the route search processing unit 19 is provided with a selectable route search function including a recommended route search function, a distance priority search function, and a high precision priority route search function. .

  The recommended route search function uses the information of the basic link cost CL set in advance as the link attribute information of each road link k as it is, and searches for a route so that the total of the basic link cost CL in the entire route is minimized. It is a function to perform. Here, the basic link cost CL is information obtained by quantifying the time required to pass an actual road corresponding to each road link k, ease of passing, and the like, and the road length (road link) of each road link k. Length) and road attributes. As the road attribute, for example, values corresponding to the speed limit, the road type, the number of lanes, and the like are set. In this case, it is preferable that the basic link cost CL is set to be smaller as the road length is shorter, smaller as the speed limit is higher, and smaller as the road size indicated by the road type or the number of lanes is larger. In the present embodiment, the node cost CN is similarly set for each intersection node n between the road links k. Therefore, the recommended route search function in the present embodiment considers the node cost CN in addition to the basic link cost CL, and performs route search so that the sum of the basic link cost CL and the node cost CN in the entire route is minimized. Do. Here, the node cost CN is information obtained by quantifying the time required to pass through the actual intersection corresponding to each intersection node n, the ease of passing, and the traveling direction (right turn, left turn, Straight ahead, etc.), and a value corresponding to the presence or absence of a signal is set. In this case, it is preferable that the node cost CN is larger in the order of the straight direction, the left turn, and the right turn in the traveling direction (in the case of left-hand traffic), and the intersection with a signal is set larger than the intersection without a signal. Therefore, with this recommended route search function, it is possible to search for a route that can be comfortably reached in a relatively short time from the departure point to the destination.

  The distance priority search function is a function for performing a route search so that the sum of the road lengths in the entire route is minimized by using road length information set in advance as link attribute information of each road link k. Therefore, the shortest distance route from the starting point to the destination can be searched by this distance priority search function.

  The high-accuracy priority route search function accurately determines the position of the host vehicle C when performing a route search so that the total cost of the entire route is minimized based on the link cost set for each road link k. This is a function of setting the link cost of a road link k (hereinafter referred to as “high-precision link kh”) that can be specified to be relatively smaller than that of other road links k (hereinafter referred to as “normal link ko”). That is, the high-accuracy priority route search function specifies the position of the host vehicle C with high accuracy by setting the link cost of the high-accuracy link kh to be relatively smaller than the normal links ko other than the high-accuracy link kh. This is a route search function that searches for a route that preferentially passes through a road that can be used. Here, by setting the link cost of the high-precision link kh to be smaller than the link cost of the normal link ko having the same basic link cost CL value, the link cost of the high-accuracy link is set relatively to that of the normal link ko. We are going to set it small. In the present embodiment, the route search processing unit 19 includes a cost correction calculation unit 20 for correcting the link cost. In the following description, “road link k” is a generic term for “high-precision link kh” and “normal link ko”.

  The high-precision link kh is a road link k that may be able to specify the position of the host vehicle C with higher accuracy than the normal link ko by acquiring and using information unique to each road link k. Information specific to each road link k includes, for example, feature information F of features provided on the road corresponding to each road link k, specific information transmitted from a transmitter provided on the road, and the like. is there. In the present embodiment, on the basis of the feature information F stored in the feature database DB2, a feature that can be used for specifying a highly accurate position in the traveling direction of the host vehicle C by the host vehicle position correcting unit 25, The road link k in which one or both of the features that can be used for specifying the driving lane of the host vehicle C by the driving lane specifying unit 26 is defined as the high-precision link kh. Furthermore, the road link k that can receive the specific information that can be used for specifying the travel lane of the host vehicle C by the external information receiving unit 24 is also a high-precision link kh.

  As described above, the own vehicle position correcting unit 25 is based on the image recognition result of the feature by the image recognition unit 23 and the position information of the target feature included in the feature information F acquired from the feature database DB2. The vehicle position information P is corrected. Therefore, the road link k where there is a feature that can be used for specifying a highly accurate position in the traveling direction of the host vehicle C by the host vehicle position correcting unit 25 can be recognized by the image recognition unit 23. There is a condition that an object exists and the feature information F of the feature is stored in the feature database DB2. Therefore, for example, as shown in FIG. 5, the feature of the pedestrian crossing (target feature ft) exists on the road surface so that the image can be recognized, and the feature information F about the feature is stored in the feature database DB2. If it is, the road link k is a high-precision link kh. Note that the feature types of features that can be used to correct the vehicle position information P in the vehicle position correction unit 25 are not limited to pedestrian crossings, and feature information is stored in the feature database DB2. Various feature types in which F is stored are targeted.

  Further, as described above, the travel lane identification unit 26 identifies the travel lane of the host vehicle C based on the result of the image recognition processing by the image recognition unit 23 and the feature information F acquired from the feature database DB2. Specifically, the traveling lane specifying unit 26 uses the image recognition result of the lane markings that divide each lane and the feature information F of the lane markings to determine the traveling lane of the host vehicle C by combining the types of lane markings. Identify. In addition, the traveling lane specifying unit 26 uses the image recognition result of features of different types and forms provided in each lane and the feature information F of the feature to match the feature that has been image-recognized. The lane in which the feature is provided is specified as the traveling lane of the host vehicle C. Therefore, road links k on which features that can be used to identify the traveling lane of the host vehicle C by the traveling lane identifying unit 26 include features that can be image-recognized by the image recognizing unit 23. The feature information F of the feature is stored in the feature database DB2, and the combination of the types of lane markings on both sides of each lane is different from each other, or there is a feature of a different type or form in each lane. It is a condition to do. Therefore, for example, features (target features ft) such as lane markings and traveling direction markings according to traveling directions as shown in FIGS. 7 to 9 exist so as to be image recognizable, and feature information F about the features is present. When stored in the feature database DB2, the road link k is a high-precision link kh.

  Further, as described above, the external information receiving unit 24 receives, from the outside of the host vehicle C, specific information that can be used for specifying the position of the vehicle C, such as VICS information. Therefore, the road link k corresponding to the road where the host vehicle C can receive specific information such as VICS information, specifically, the road where a transmitter or the like for transmitting such specific information is installed. The corresponding road link k is a high-precision link kh.

  When executing the high-precision priority route search function, the route search processing unit 19 refers to the map database DB1 and the feature database DB2, and is a high-precision link kh for each road link k that is a candidate for the route. Or normal link ko. In addition, the route search processing unit 19 may determine whether the position of the traveling direction of the host vehicle C is highly accurate for each road link k determined as the highly accurate link kh, or the host vehicle C. It is determined whether there is a high-accuracy link kh that can specify the travel lane with high accuracy, or a high-accuracy link kh that can specify both of them with high accuracy.

  As described above, the cost correction calculation unit 20 of the route search processing unit 19 sets the link cost of the high-precision link kh to be smaller than the link costs of other road links k having the same basic link cost CL value. The link cost is corrected. In the present embodiment, when the cost correction calculation unit 20 executes the high-accuracy priority route search function, the value set for the high-accuracy link kh is smaller than the value set for the normal link ko. Using the coefficient A, the basic link cost CL set in advance for each road link k is multiplied by the high-accuracy correction coefficient A to calculate the correction link cost for each road link k. Then, when executing the high-accuracy priority route search function, the route search processing unit 19 performs a route search using the correction link cost calculated by the cost correction calculation unit 20.

  FIG. 11 is a diagram illustrating an example of a set value of the high-precision correction coefficient A. As shown in this figure, in the high accuracy correction coefficient A, the value set for the high accuracy link kh is smaller than the value set for the normal link ko. Further, in the present embodiment, the high-accuracy correction coefficient A is a value set in the high-accuracy link kh that may identify the position of the traveling direction of the host vehicle C with high accuracy, and the travel lane of the host vehicle C. Is set to a high-precision link kh that may be able to specify both the position in the traveling direction of the host vehicle C and the travel lane with high accuracy. The value to be set is determined separately. Specifically, the high-accuracy correction coefficient A of the high-accuracy link kh that may be able to specify the position of the traveling direction of the own vehicle C with high accuracy is “0.8”, and the traveling lane of the own vehicle C is highly accurate. The high accuracy correction coefficient A of the high accuracy link kh that can be specified is “0.8”, and the high accuracy link kh that can specify both the position in the traveling direction of the host vehicle C and the travel lane with high accuracy. The high-precision correction coefficient A is set to “0.64”. Note that the high-accuracy correction coefficient A of the high-accuracy link kh that may be able to specify both the position in the traveling direction and the traveling lane with high accuracy is the high-accuracy correction coefficient A “0. It is also suitable as a configuration that is obtained each time by multiplying “8” by the high-precision correction coefficient A “0.8” when the travel lane can be specified.

  Further, as described above, in the present embodiment, the node cost CN is similarly set for each intersection node n between the road links k. Therefore, in the high-accuracy priority route search function in this embodiment, the route search processing unit 19 considers the node cost CN in addition to the corrected link cost obtained by correcting the basic link cost CL, and corrects the entire route. The route search is performed so that the sum of the link cost and the node cost CN is minimized.

  Next, a difference between the three route search functions executed by the route search processing unit 19, that is, the recommended route search function, the distance priority search function, and the high accuracy priority route search function will be described using a specific example. FIG. 12 is a diagram showing an example of road information R used for explaining this specific example. In this figure, a to h surrounded by circles indicate intersection nodes n, and straight lines connecting the intersection nodes n indicate road links k. “CL = xxx” indicates the value of the basic link cost CL of each road link k, and “CN = xxx” indicates the value of the node cost CN of each intersection node n. “L = xxx” indicates the road length (road link length) of each road link k. The symbol of “advance” surrounded by a rectangular frame is a high-precision link kh that may allow the road link k adjacent to the symbol to identify the position in the traveling direction of the host vehicle C with high accuracy. It is shown that. The symbol “re” surrounded by a square frame indicates that the road link k adjacent to the symbol is a high-precision link kh that can identify the traveling lane of the host vehicle C with high accuracy. Show. In the example shown in this figure, the routes from the departure point a to the destination h are “abbe”, “acfh”, and “adgh”. There are three paths.

Here, when the recommended route search function is selected by the user, the route search processing unit 19 performs a route search as follows to determine a searched route. That is, the route search processing unit 19 calculates the total of the basic link cost CL and the node cost CN for the entire route for each of the three routes from the departure point a to the destination h, and the total cost is the smallest. Is determined as a search route. In the case of this example, the total cost of the route “abbeh” is obtained by the following equation (1).
Total cost = 300 + 50 + 500 + 0 + 300 = 1150 ... (1)
Similarly, the total cost of the route “acfh” is obtained by the following equation (2).
Total cost = 200 + 100 + 400 + 100 + 300 = 1100 ... (2)
In addition, the total cost of the route “adgh” is obtained by the following equation (3).
Total cost = 200 + 0 + 400 + 50 + 400 = 1050 (3)
Therefore, the route search processing unit 19 determines the route “adgh” having the lowest total cost as a search route by the recommended route search function.

When the distance priority search function is selected by the user, the route search processing unit 19 performs a route search as follows and determines a search route. That is, the route search processing unit 19 calculates the total of the road length L in the entire route for each of the three routes from the departure point a to the destination h, and finds the route having the minimum total road length. It is determined as a search route. In the case of this example, the total road length of the route “abbeh” is obtained by the following equation (4).
Total road length = 200 + 600 + 300 = 1100 (4)
Similarly, the total road length of the route “acfh” is obtained by the following equation (5).
Total road length = 200 + 300 + 400 = 900 (5)
Further, the total road length of the route “adgh” is obtained by the following equation (6).
Total road length = 300 + 500 + 200 = 1000 ... (6)
Therefore, the route search processing unit 19 determines the route “acfh” having the shortest total road length as the search route by the distance priority search function.

  On the other hand, when the high precision priority route search function is selected by the user, the route search processing unit 19 performs a route search as follows to determine a searched route. That is, the route search processing unit 19 determines, for each of the three routes from the departure point a to the destination h, whether the road link k constituting each route is a high-precision link kh or a normal link ko. Then, the basic link cost CL is used as it is for the normal link ko, and the basic link cost CL is corrected by the high accuracy correction coefficient A for the high accuracy link kh to calculate the correction link cost. At this time, as shown in FIG. 11, there is a high possibility that the position of the traveling direction of the host vehicle C may be specified with high accuracy, and the traveling lane of the host vehicle C may be specified with high accuracy. The accuracy link kh and the high-precision correction coefficient A having a value set for each of the high-accuracy links kh that may be able to specify both of them with high accuracy are used. Therefore, for a high-accuracy link kh that may be able to specify the position in the traveling direction of the host vehicle C with high accuracy, such as an ab link, for example, a high-accuracy correction of 0.8 is added to the basic link cost CL. Multiply coefficient A. For a high-accuracy link kh that can identify the traveling lane of the host vehicle C with high accuracy, such as an e-h link, for example, a high-accuracy correction coefficient A of “0.8” is added to the basic link cost CL. Multiply For a high-precision link kh that may be able to specify both the position in the traveling direction and the travel lane with high accuracy, such as the be-e link, the basic link cost CL has a high accuracy of “0.64”. Multiply the correction coefficient A. Then, the total of the corrected link cost (including the basic link cost CL that is used as it is for the normal link ko) and the node cost CN is calculated for the entire route, and the route having the minimum total cost is determined as the search route.

In the case of this example, the total cost of the route “abbeh” is obtained by the following equation (7).
Total cost = 300 * 0.8 + 50 + 500 * 0.64 + 0 + 300 * 0.8 = 850 ... (7)
Similarly, the total cost of the route “acfh” is obtained by the following equation (8).
Total cost = 200 + 100 + 400 * 0.8 + 100 + 300 = 1020 (8)
In addition, the total cost of the route “adgh” is obtained by the following equation (9).
Total cost = 200 * 0.8 + 0 + 400 + 50 + 400 = 1010 (9)
Therefore, the route search processing unit 19 determines the route “ab-eh” having the lowest total cost as a search route by the high-precision priority route search function. By performing the route search processing as described above, it is possible to search for a route that preferentially passes a road that can specify the position of the vehicle with high accuracy.

12 Procedure for Route Search Processing Next, a procedure for route search processing executed in the navigation device 1 according to the present embodiment will be described. FIG. 13 is a flowchart showing a procedure of route search processing according to the present embodiment. The processing procedure described below is executed by hardware and / or software (program) or both of the above-described functional units. When each of the above functional units is configured by a program, the arithmetic processing device included in the navigation device 1 operates as a computer that executes the navigation program that configures each of the above functional units. Hereinafter, it demonstrates according to a flowchart.

  As shown in FIG. 13, in the route search process in the navigation device 1, the route search processing unit 19 first determines whether or not there is an input of a destination (step # 01). Here, the destination is input by the user operating the display input device 27 and inputting a predetermined condition and selecting from the search or designating a point on the map. The departure point is the current position of the host vehicle C indicated by the host vehicle position information P unless otherwise specified by the user. When the destination is input (step # 01: Yes), for example, a search function selection screen on which a plurality of route search functions can be selected is displayed on the display input device 27 as shown in FIG. (Step # 02).

  When “high accuracy priority” is selected on this search function selection screen (step # 03: Yes), the route search processing unit 19 executes the high accuracy priority route search function (step # 04). As described above, the high-accuracy priority route search function specifies the position of the host vehicle C with high accuracy by setting the link cost of the high-accuracy link kh to be relatively smaller than the normal links ko other than the high-accuracy link kh. This is a function for searching for a route that preferentially passes a road that can be used. If “recommended” is selected on the search function selection screen (step # 05: Yes), the route search processing unit 19 executes the recommended route search function (step # 06). As described above, the recommended route search function uses the information of the basic link cost CL of each road link k as it is, and performs a route search so that the sum of the basic link cost CL and the node cost CN in the entire route is minimized. It is a function. When “distance priority” is selected on the search function selection screen (step # 07: Yes), the route search processing unit 19 executes the distance priority search function (step # 08). As described above, the distance priority search function is a function that performs route search using the information on the road length of each road link k so that the total road length in the entire route is minimized.

  As described above, when any one of the route search functions is selected and the route search is executed, and the resulting search route is determined (step # 09), the navigation device 1 is operated by the guidance processing unit 21. In accordance with the determined route, appropriate route guidance is provided to the user. As described above, this route guidance is performed by guidance display on the display screen of the display input device 27, voice guidance by the voice output device 28, or the like. This is the end of the route search process.

13. Other Embodiments (1) In the above-described embodiment, the high-precision link kh may be able to specify the position in the traveling direction of the host vehicle C with high accuracy. It is determined whether there are three types of high-accuracy link kh that can be specified with high accuracy and high-accuracy link kh that may be able to specify both of them with high accuracy. The case where the value of the high accuracy correction coefficient A is used has been described as an example. However, the embodiment of the present invention is not limited to this. Therefore, for example, it is also one of the preferred embodiments of the present invention to use a predetermined value of the high-precision correction coefficient A individually for each road link k. In this case, since the value of the high-precision correction coefficient A can be set individually for each road link k, there is a possibility that the position of the host vehicle C can be specified with high precision when traveling on each road link k. It is possible to set an appropriate value according to. Further, such information on the high-accuracy correction coefficient A becomes individual information for each road link k. Therefore, for example, it is preferable to have a configuration stored in the map database DB1 as link attribute information for each road link k.

(2) In the above embodiment, depending on whether the high-precision correction coefficient A can identify the position of the host vehicle C in the traveling direction, the traveling lane of the host vehicle C, or both. The case where the values are different has been described as an example. However, the embodiment of the present invention is not limited to this. Therefore, for example, it is also a preferred embodiment of the present invention that the high-accuracy correction coefficient A is set to a different value depending on the possibility that the position of the host vehicle can be specified with high accuracy. In this case, it is preferable that the high-accuracy correction coefficient A is set so as to decrease as the possibility that the position of the host vehicle C can be specified with high accuracy increases. If the high-accuracy correction coefficient A is set in this way, the correction link cost after correction by the high-accuracy correction coefficient A can be reduced as the possibility that the position of the host vehicle C can be specified with high accuracy increases. Therefore, the high-accuracy priority route search function makes it possible to search for a route that preferentially passes on a road that has a high possibility of specifying the position of the host vehicle C with high accuracy.

(3) In the above embodiment, when executing the high-accuracy priority route search function, the high-accuracy correction coefficient A is set so that the value set for the high-accuracy link kh is smaller than the value set for the normal link ko. The case where the route search processing unit 19 performs a route search using the result obtained by multiplying the basic link cost CL set in advance for each road link k by the high-precision correction coefficient A as the correction link cost has been described as an example. . However, such a method for setting the high-precision correction coefficient A and a method for calculating the correction link cost are merely examples. Therefore, for example, when executing the high-accuracy priority route search function, the value set for the road link k (high-accuracy link kh) that may identify the position of the host vehicle C with high accuracy is the possibility. The result of subtracting the high-accuracy correction coefficient A from the basic link cost CL set in advance for each road link k, using a high-accuracy correction coefficient A that is larger than the value set for the road link k with no traffic (normal link ko) It is also a preferred embodiment of the present invention that the route search processing unit 19 performs a route search using as a correction link cost. In addition, for example, the value set for the road link k (high-precision link kh) that may be able to specify the position of the host vehicle C with high accuracy is set to the road link k (normal link ko) that has no possibility. The route search processing unit 19 uses the result obtained by adding the high accuracy correction coefficient to the basic link cost CL set in advance for each road link k as the correction link cost using the high accuracy correction coefficient A smaller than the calculated value. Searching is also one of the preferred embodiments of the present invention.

(4) In the above embodiment, when the route search processing unit 19 executes the high-precision priority route search function, the basic link cost CL preset for each road link k is corrected by the high-precision correction coefficient A. Thus, the case where the corrected link cost is calculated and the route search is performed using the corrected link cost has been described as an example. However, the embodiment of the present invention is not limited to the one using such a high precision correction coefficient A. Therefore, for example, when the route search processing unit 19 executes the high-accuracy priority route search function, for each road link k (high-accuracy link kh) that may be able to specify the position of the host vehicle C with high accuracy, It is also preferable that the route search is performed using the high-precision priority link cost set to a value smaller than the basic link cost CL set in advance for the link k in the same manner as the correction link cost. This is one of the embodiments. In this case, since the value of the high-accuracy priority link cost can be set individually for each road link k, the position of the host vehicle C can be specified with high precision when traveling on each road link k. It is possible to set an appropriate value according to the sex. Further, such high-accuracy priority link cost information becomes individual information for each road link k, and therefore, for example, it is preferable to have a configuration stored in the map database DB1 as link attribute information of each road link k.

(5) In the above embodiment, in addition to the high-precision priority route search function, the route search processing unit 19 performs recommended route search function and distance priority in which a route search is performed under conditions different from the high-precision priority route search function. The case where the two route search functions of the search function are selectable has been described as an example. However, the embodiment of the present invention is not limited to this. Therefore, for example, in addition to the three route search functions described above, a configuration including a toll road priority search function and a general road priority search function so as to be selectable is also one preferred embodiment of the present invention. In addition to the high-precision priority route search function, one of the recommended route search function, the distance priority search function, the toll road priority search function, the general road priority search function, or a route search function other than these, or A configuration in which three or more route search functions are selectably provided is also a preferred embodiment of the present invention. Here, the toll road priority search function sets the link cost for the road link k of the toll road relatively smaller than other road links k so that the total link cost of the entire route is minimized. This is a function for performing a route search. In addition, the general road priority search function sets the link cost for the road link k of the general road relatively smaller than the other road links k, and the route so that the total link cost of the entire route is minimized. This is a search function.

(6) In the above embodiment, the external information receiving unit 24 as the information receiving unit receives, as an example, a configuration in which specific information (VICS beacon information) that can be used for specifying the driving lane of the vehicle is received from the outside. explained. However, the embodiment of the present invention is not limited to this, and other specific information can be received from the outside as a matter of course. Therefore, for example, it is also preferable that the external information receiving unit 24 receives specific information that can be used for specifying the position in the traveling direction of the host vehicle from a transmitter provided on the road surface. This is one of the embodiments. It is also possible to combine the above and receive a specific information that can be used to specify both the position in the traveling direction of the host vehicle and the traveling lane of the host vehicle from the outside of the host vehicle. One of the forms.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a navigation device having a route search function for searching for a route from a departure place to a destination based on road information representing a road network based on a connection relation of a plurality of road links. .

The block diagram which shows schematic structure of the navigation apparatus which concerns on embodiment of this invention. The figure which shows the own vehicle where the navigation device is installed The figure which shows the example of a structure of the map information memorize | stored in the map database The figure which shows the example of the feature information of the road marking memorize | stored in the feature database The figure which shows the example of the condition of the own vehicle at the time of image-recognizing a target feature and correcting own vehicle position information The figure which shows the example of the image information used for specification of the traveling lane of the own vehicle The figure which shows the example of the feature information around the own vehicle used for specification of the driving lane of the own vehicle The figure which shows an example in case the combination of the division line type of both sides of each lane differs from each other The figure which shows the example when the feature of different classification and form exists in each lane The figure which shows the example of the search function selection screen which displayed several route search functions so that selection was possible The figure which shows an example of the setting value of a high precision correction coefficient The figure which shows an example of the road information for demonstrating the difference of several route search functions Flow chart showing the procedure of route search processing

Explanation of symbols

1: Navigation device 19: route search processing unit (route search means)
24: External information receiving unit (information receiving means)
29: Own vehicle position specifying means C: Own vehicle R: road information k: road link n: intersection node CL: basic link cost CN: node cost L: road length A: high accuracy correction coefficient DB2: feature database F: ground Object information G: Image information

Claims (13)

A navigation device comprising route search means for searching a route from a departure place to a destination based on road information representing a road network by connection relations of a plurality of road links,
The route search means can accurately identify the position of the host vehicle when performing a route search so that the total cost of the entire route is minimized based on the link cost set for each road link. A navigation device having a high-precision priority route search function for setting a link cost of a road link having a characteristic smaller than that of other road links.   When the route search means executes the high-accuracy priority route search function, a value set for a road link that may be able to specify the position of the host vehicle with high accuracy is changed to a road link that does not have that possibility. A route search is performed using a result obtained by multiplying a basic link cost preset for each road link by the high accuracy correction coefficient as the link cost using a high accuracy correction coefficient smaller than a set value. Item 4. The navigation device according to Item 1.   The high-accuracy correction coefficient is a value set in a road link that may be able to specify the position of the traveling direction of the host vehicle with high accuracy, and a road link that may be able to specify the traveling lane of the host vehicle with high accuracy. The value set for the road link and the value set for the road link that may be able to specify both the position in the traveling direction of the host vehicle and the travel lane with high accuracy are predetermined. Navigation device.   The navigation device according to claim 2, wherein the high-accuracy correction coefficient is determined in advance for each road link in accordance with a possibility that the position of the host vehicle can be specified with high accuracy when traveling on each road link.   The navigation device according to any one of claims 2 to 4, wherein the high-accuracy correction coefficient is set to a smaller value as the possibility that the position of the host vehicle can be identified with high accuracy increases.   The navigation device according to any one of claims 2 to 5, wherein the basic link cost is set according to a road length and a road attribute of each road link.   When the route search means executes the high-accuracy priority route search function, a value set for a road link that may be able to specify the position of the host vehicle with high accuracy is changed to a road link that does not have that possibility. Possibility of specifying the result of subtracting the high-accuracy correction coefficient from the basic link cost preset for each road link or the position of the host vehicle with a high-accuracy correction coefficient that is larger than the set value A high-precision correction coefficient is set to a basic link cost set in advance for each road link using a high-precision correction coefficient whose value set for a certain road link is smaller than a value set for a road link that has no possibility. The navigation device according to claim 1, wherein a route search is performed by using a result obtained by adding as a link cost.   The route search means, when executing the high-accuracy priority route search function, for the road links that may be able to specify the position of the host vehicle with high accuracy than the basic link cost set in advance for each road link. The navigation device according to claim 1, wherein a route search is performed using a high-accuracy priority link cost set to a small value as the link cost. Referring to the feature database storing the feature information including the position information and attribute information of the feature, the image recognition result of the feature included in the image information obtained by photographing the periphery of the host vehicle is collated with the feature information. The vehicle position specifying means for specifying the position of the vehicle with high accuracy,
Based on the feature information stored in the feature database, the vehicle position specifying means may be used to specify a feature that can be used for specifying a position in the traveling direction of the host vehicle and a traveling lane of the host vehicle. The navigation apparatus according to any one of claims 1 to 8, wherein a road link on which one or both of the possible features are present is a road link that is capable of specifying the position of the host vehicle with high accuracy. It further comprises information receiving means for receiving from the outside of the host vehicle specific information that can be used to specify one or both of the position in the traveling direction of the host vehicle and the traveling lane of the host vehicle,
The navigation device according to any one of claims 1 to 9, wherein the road link that can receive the specifying information is a road link that can specify the position of the host vehicle with high accuracy.   11. The route search unit according to claim 1, wherein the route search means performs a route search based on a node cost set for each intersection node in addition to the link cost so that a total cost of the entire route is minimized. The navigation device according to any one of the above.   The route search means is provided with one or two or more route search functions for performing a route search under conditions different from the high-precision priority route search function in addition to the high-precision priority route search function. The navigation device according to any one of 1 to 11. A route search function for searching a route from a departure place to a destination based on road information representing a road network by a connection relation of a plurality of road links,
When a route search is performed so that the total cost of the route as a whole is minimized based on the link cost set for each road link, the position of the host vehicle may be determined with high accuracy. A navigation program for causing a computer to realize a high-accuracy priority route search function for setting a link cost relatively smaller than other road links.

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