JP2010008261A - Navigation system and t-intersection detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation system and a T-intersection determination method for more appropriately detecting T-intersections. <P>SOLUTION: The navigation system determines points of intersection 421, 422, and 423 (d) between a circle 420, having a prescribed radius on a target intersection node 410 and segments on roads to which segments connecting to the node 410 belong. The navigation system determines directions 431, 432, and 433 (e), from the target intersection node 410, to each point of intersection. It is determined as to whether the three directions satisfy prescribed relations. Only when they satisfy the prescribed relations, is the target intersection determined as being a T-intersection. The prescribed relations are ¾A-B¾=180°±Δ; ¾A-C¾=90°±Δ; and ¾B-C¾=90°±Δ (where each of the three directions is selected exclusively from among A, B and C). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for guiding an intersection in a navigation device mounted on an automobile.

As a technique for guiding an intersection in a navigation device mounted on an automobile, a technique for detecting the shape of an intersection from a connection direction of a road to the intersection obtained from map data is known (for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 2001-215129 Japanese Patent Laid-Open No. 5-46082

Now, in map data, a road network is generally expressed as a continuous body of straight lines.
Further, the road network around the intersection 400 that is not a T-junction intersection having a shape as shown in FIG. 4a may be represented as a continuous line of straight lines as shown in FIG. 4b in the map data.
When the road network is represented as shown in FIG. 4b, when the shape of the intersection is detected from the connection direction of the road with respect to the intersection, as shown in FIG. 4c, the three connected to the connection point 410 corresponding to the intersection are displayed. Since the straight lines 411, 412, and 413 are connected in a T-shape at the connection point 410, the intersection is erroneously detected as a T-shaped intersection.

  Then, this invention makes it a subject to detect a T-junction intersection more appropriately.

  In order to achieve the above object, the present invention provides a navigation device that performs intersection guidance based on road map data representing a road network shape, and determines whether or not the intersection performing intersection guidance is a T-junction intersection. Road intersection judging means and intersection guidance means for performing intersection guidance, and when the intersection is a T-junction intersection, intersection guidance means for performing guidance including that the intersection is a T-junction intersection In the T-junction intersection determination means, there are three roads connected to the intersection where the intersection guidance is obtained, which is obtained from the road map data, and is connected to the intersection where the intersection guidance is obtained, which is obtained from the road map data. Three directions on the three roads where the distance from the intersection that performs the intersection guidance is a predetermined distance to the three points that are directed from the intersection that performs the intersection guidance are the intersection. If it is extending in a T-shape from the intersection of the guidance, in which an intersection of performing the intersection guidance is to be determined as a T-junction intersection.

  In order to achieve the above object, a T-junction intersection determination method for determining whether an intersection is a T-junction intersection based on road map data representing a road network shape is based on the road map data. First step for determining whether or not there are three roads connected to the intersection, and when it is determined that there are not three roads connected to the intersection, it is determined that the intersection is not a T-junction intersection In the second step, when it is determined that there are three roads connected to the intersection, based on the road map data, the distance from the intersection on the three roads connected to the intersection is a predetermined distance. The third step of determining whether or not the three directions from the intersection are extending in a T-shape from the intersection, and the three determined points , The intersection When it is determined that the three directions facing away from the intersection do not extend in a T-shape, the fourth step for determining that the intersection is not a T-junction intersection, and the calculated three points at the intersection When it is determined that the three directions from the intersection extend in a T shape from the intersection, the fifth step determines that the intersection is a T-junction intersection.

  In order to achieve the above object, the present invention provides the road network as a map data creation method for creating road map data representing a road network shape and whether or not each intersection is a T-junction. Based on the shape of the road network, the first step of determining whether or not there are three roads connected to the intersection, and if it is determined that there are three roads connected to the intersection, The three points on the three roads connected to the intersection are determined to have a predetermined distance from the intersection, and the three directions from the intersection are T-shaped from the intersection to the obtained three points. A second step for determining whether or not the vehicle has extended to the three points, and if the three directions from the intersection are determined to extend in a T-shape from the intersection to the obtained three points, the intersection Is a T-junction intersection Also provides the third map data generation method and a step of registering the identification to the map data.

  Here, in the above navigation device, T-junction intersection determination method, and map data creation device, the determination that the three directions toward the three points obtained from the intersection extend in a T shape from the intersection is as follows. The angle difference between the two directions among the three directions is within the range of 180 degrees ± predetermined allowable angle range, and the angle difference with respect to the other direction of the remaining one direction is 90 degrees ± predetermined allowable angle range If the angle is within the angle range, it may be determined that the three directions extend in a T shape from the intersection.

  As described above, according to the present invention, instead of determining whether or not the intersection is a T-junction intersection from the connection direction of the road to the intersection, from the intersection on the three roads connected to the intersection. Whether or not the intersection is a T-junction is determined depending on whether or not the three directions from the intersection extend in a T-shape from the intersection to the three points where the distance is a predetermined distance. Therefore, it is possible to determine whether or not the intersection is a T-junction intersection from the overall shape of the road. Therefore, even when a road in the vicinity of an intersection that is not a T-junction intersection is expressed in a T-shape in map data, the intersection is not erroneously determined as a T-junction intersection. A T-junction intersection can be detected more appropriately.

  As described above, according to the present invention, a T-junction intersection can be detected more appropriately.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows the configuration of the navigation system according to the present embodiment.
The navigation system is a system mounted on an automobile, and includes a navigation device 1, a speaker 2, an operation unit 3, a display device 4, a vehicle state sensor 5, and a GPS receiver 6, as shown in the figure. Configured.
Here, the vehicle state sensor 5 is various sensors that detect various vehicle states, such as an azimuth sensor such as an angular acceleration sensor or a geomagnetic sensor, or a vehicle speed sensor such as a vehicle speed pulse sensor.
The navigation device 1 includes a storage device 11 such as an HDD that stores map data representing a map, a current state calculation unit 12, a route search unit 13, a memory 14, a voice generation unit 15 that generates voice and outputs it from the speaker 2. A control unit 16, a guide image generation unit 17, and a GUI control unit 18 that controls input and output with the user using the operation unit 3 and the display device 4 are provided.

  However, the above navigation apparatus 1 may be a CPU circuit having a general configuration including peripheral devices such as a microprocessor, a memory, and other graphic processors and geometric processors in terms of hardware. In this case, each unit of the navigation device 1 described above may be realized as a process embodied by a microprocessor executing a program prepared in advance. In this case, such a program may be provided to the navigation apparatus 1 via a recording medium or an appropriate communication path.

Next, FIG. 2 a shows the contents of the map data stored in the storage device 11.
As shown in the figure, the map data includes management data describing the version of the map data, route data representing information on each road route, and basic map data representing a map.
The basic map data includes a road unit representing a road network and a drawing unit representing drawing objects (such as place names and topographical figures) other than roads included in the map.
Here, in the road network data, a road network is defined as a set of nodes that represent intersections and links that connect the nodes, and the shape of each link is expressed as a connected body of segments that are straight lines. Each segment is defined by a node at both ends of the link and a shape point that is a connection point of the segments in the link arranged on the link. That is, the road between the intersection A and the intersection B of the road network as shown in FIG. 2b includes a node N1 corresponding to the intersection A, a node N2 corresponding to the intersection B, a node N1 and a node as shown in FIG. The shape of the link L (N1N2), which is modeled as a link L (N1N2) connecting N2 and has both ends of the node N1 and the node N2, is defined by segments SG1 to SG6 sequentially connected by shape points SP01 to SP05. The

The road unit has node data provided for each node and link data provided for each link.
Each node data includes a node number as an identifier of the corresponding node, a node attribute indicating various attributes of the corresponding node, a node coordinate indicating the position of the corresponding node, a connection link list, and a connection node list. The connection link number indicating the link number of the link connected to the corresponding node is registered in the connection link list, and the nodes of other nodes connected to the corresponding node via one link are registered in the connection node list. A connection node number representing the number is registered.

  Each link data includes a link number that is an identifier of the corresponding link, a link attribute that represents various attributes of the corresponding link, a first end point node that represents the node numbers of two nodes that are end points of the corresponding link, and the first end node Two end point nodes and a shape point list are registered. Also, in the shape point list of the link data, the shape point coordinates indicating the coordinates of the shape point on the corresponding link are passed according to the order of passing through the corresponding link from the first end point node toward the second end point node. sign up.

  In such a configuration, the current state calculation unit 12 of the navigation device 1 uses the road of the map data read from the storage device 11 for the current position estimated from the outputs of the vehicle state sensor 5 and the GPS receiver 6. Map matching processing with the map around the current position determined last time indicated by the unit is performed, and the most probable coordinates as the current position and the most probable direction as the current traveling direction are respectively determined as the current position and the current traveling direction. And set in the memory 14.

  In addition, the control unit 16 receives a destination setting from the user via the operation unit 3 and the GUI control unit 18 and sets the destination setting in the memory 14. Then, the route search unit 13 is caused to search for a guidance route to the destination. The route search unit 13 reads out map data of a necessary geographical range from the storage device 11, and based on a cost model such as a minimum distance and a minimum time for a route with the minimum cost from the current position set in the memory 14 to the destination. The searched route is set in the memory 14 as a guided route.

Further, when the current position set in the memory 14 becomes near the destination, the control unit 16 determines that the destination has arrived and performs processing for clearing the destination and the guidance route set in the memory 14. .
In addition, the guide image generation unit 17 refers to the current position set in the memory 14 and generates a map image representing the map around the current position indicated by the map data at a scale set by the user. Further, the guide image generation unit 17 draws a graphic representing the current position set in the memory 14 on the drawn map image, and displays the guide image as a guide image on the display device 4 via the GUI control unit 18. Repeat. Here, when the destination and the guidance route are set in the memory 14, the guidance image generation unit 17 also displays the graphic representing the portion within the map display range represented by the map image of the guidance route indicated by the guidance route. To display. Further, when the destination is included in the map display range, a graphic representing the destination is further included in the guide image and displayed.

Hereinafter, an intersection guidance process performed by the control unit 16 when a destination or a guidance route is set in the memory 14 in such a configuration, that is, during route guidance will be described.
FIG. 3a shows the procedure of this intersection guidance process.
As shown in the figure, in this process, referring to the current position and the guidance route set in the memory 14, the approach of a predetermined distance (for example, 300 m) to the next route change intersection on the guidance route of the current position is monitored. (Step 302). Here, the route change intersection is an intersection that changes the route (right turn / left turn, etc.) when traveling according to the guidance route.

  When the next course change intersection is approached, a T-junction intersection determination process is performed with the next course change intersection as a target intersection, and whether or not the next course change intersection is a T-junction intersection is determined. Determination is made (step 304). Details of the T-junction intersection determination process will be described later.

  Then, when the next course change intersection is a T-junction intersection, the voice generation unit 15 instructs the voice generation unit 15 to change the course at the next course-change intersection such as “Turn left at the T-junction intersection 300 m ahead”. The speaker 2 outputs a voice guidance message for guiding the direction, the distance to the next route change intersection, and the fact that the next route change intersection is a T-shaped intersection (step 306). Then, the process returns to the monitoring in step 302.

  On the other hand, when the next course change intersection is not a T-junction intersection (step 304), the course change direction at the next course change intersection such as “turn left at the intersection 300m ahead” and the next course change. A voice guidance message for guiding the distance to the intersection is output to the speaker 2 (step 308). Then, the process returns to the monitoring in step 302.

The intersection guidance process performed by the control unit 16 has been described above.
Next, details of the T-junction intersection determination process performed in step 304 of the intersection guidance process will be described.
FIG. 3b shows the procedure of this T-junction intersection determination process.
As shown in the figure, in this process, it is checked whether or not the number of segments connected to the node corresponding to the target intersection targeted for the T-junction intersection determination process is 3 with reference to the map data (step 352). If it is not 3, the target intersection is determined not to be a T-junction intersection (step 360), and the process is terminated.

  On the other hand, if the number of segments connected to the node corresponding to the target intersection is three (step 352), for each of the three connection segments, the segment forming the road section to which the connection segment belongs and the node corresponding to the target intersection are A point where a circle with a predetermined radius (for example, 50 m) as the center intersects is calculated (step 354). Here, the road section to which the connection segment belongs is a road section that is closer to the connection segment than the node corresponding to the target intersection in the road to which the connection segment belongs.

  Then, it is checked whether or not the directions of the three points calculated in step 354 for the three connected segments with respect to the node corresponding to the target intersection satisfy a predetermined relationship (step 356). Here, the predetermined relationship is as follows: each of the three directions with respect to the node corresponding to the target intersection of the three points is arbitrarily selected from A, B, and C. The relationship is satisfied when = 180 ° ± Δ, | AC | = 90 ° ± Δ, and | BC | = 90 ° ± Δ. Note that Δ is an angle predetermined as an allowable value of deviation from the T-shape. Here, the predetermined relationship is a relationship that is satisfied when a straight line drawn from the node corresponding to the target intersection to each intersection forms an approximately T-shape.

If the predetermined relationship is satisfied, it is determined that the target intersection is a T-junction intersection (step 358), and the process ends. If not, the target intersection is determined not to be a T-junction intersection. (Step 360), the process ends.
The T-junction intersection determination process has been described above.
Here, FIG. 4 shows a processing example of such a T-junction intersection determination process.
Now, it is assumed that the road network around the intersection 400 having a shape as shown in FIG. 4a and not a T-junction intersection is represented as a link / segment continuum in the map data as shown in FIG. 4b.
Then, when the road network is expressed as shown in FIG. 4B, the T-junction intersection determination process with the intersection 400 as the target intersection is performed as follows.
That is, first, as shown in FIG. 4d, an intersection between a circle 420 having a predetermined radius (for example, 30 m) centered on the node 410 corresponding to the target intersection and an arbitrary segment on the road to which the segment connected to the node 410 belongs. 421, 422, and 423 are obtained. This intersection can be obtained, for example, by performing the following processing for each segment connected to the node 410.

  That is, first, a segment connected to the node 410 is set as a target segment. Then, it is checked whether or not there is a point on the target segment whose distance to the node 410 has a predetermined radius. If there is a point, the point is the intersection point. The process of updating the target segment to the segment connected on the side is performed until an intersection is found.

  Next, when the intersection points 421, 422, and 423 are obtained in this way, directions 431, 432, and 433 from the node 410 to the intersection points 421, 422, and 423 are obtained as shown in FIG. Checks whether the predetermined relationship is satisfied. FIG. 4F shows a predetermined relationship of | A−B | = 180 ° ± Δ, | A−C | = 90 ° ± Δ, and | B−C | = 90 ° ± Δ, where Δ = 30 degrees. 4 shows the relative relationship of the angular ranges in which the three directions A, B, and C can exist, and as shown in FIGS. 4g1, g2, and g3, the three directions 431, 432, As for 433, any combination of these directions may be A, B, or C, but this predetermined relationship is not satisfied. Therefore, the straight line drawn from the node 410 to each of the intersections 421, 422, and 423 does not form a T-shape, and it is correctly determined that this target intersection is not a T-shaped intersection.

  On the other hand, when the road network around the T-junction intersection is expressed as a continuous link / segment as shown in FIG. 4h in the map data, the T-junction intersection with this T-junction intersection as the target intersection. In the determination process, as shown in FIG. 4j, intersection points 521, 522, and 523 and directions 531, 532, and 533 from the node 510 corresponding to the T-junction intersections with respect to these intersection points are calculated. These directions 531, 532, and 533 satisfy the predetermined relationship shown in FIG. 4 f, as shown in the figure, and therefore the straight line drawn from the node 510 to each intersection 521, 522, and 523 is approximately T-shaped. Therefore, the target intersection is correctly determined to be a T-junction intersection.

  In determining whether or not the above-described predetermined relationship is satisfied, among the three directions obtained for the three intersections, the two directions with the largest angular difference are A and B, and the remaining directions are C. You may make it investigate whether the relationship of is satisfy | filled. Alternatively, among the three segments connected to the node corresponding to the target intersection, the directions determined for the two segments having the largest angular difference in the direction extending from the node corresponding to the target intersection are A and B, and the directions determined for the remaining segments C may be used to check whether the predetermined relationship is satisfied.

The embodiment of the present invention has been described above.
By the way, in the above embodiment, in the navigation apparatus 1, it is determined whether or not the intersection is a T-junction intersection. However, this determination is performed for each intersection when creating map data. It may be determined whether or not. In this case, the determination result for each intersection is stored in the map data as the node attribute of the node data of the node corresponding to each intersection. In the navigation device 1, each intersection is a T-junction intersection. Is determined from the node attribute of the node corresponding to the intersection. That is, for example, in the intersection guidance process of FIG. 3a, in step 304, it is determined from the node attribute of the node data of the node corresponding to the next route change intersection whether or not the next route change intersection is a T-junction intersection. To do.

  As described above, according to this embodiment, instead of determining whether the intersection is a T-junction intersection from the connection direction of the road to the intersection, the intersection on the three roads connected to the intersection Whether or not the intersection is a T-junction depending on whether or not three directions from the intersection extend in a T-shape from the intersection to three points whose distance from the intersection is a predetermined distance Therefore, it is possible to determine whether or not the intersection is a T-shaped intersection from the overall shape of the road. Therefore, even when a road in the vicinity of an intersection that is not a T-junction intersection is expressed in a T-shape in map data, the intersection is not erroneously determined as a T-junction intersection. A T-junction intersection can be detected more appropriately.

It is a block diagram which shows the structure of the navigation system which concerns on embodiment of this invention. It is a figure which shows the map data with which the navigation apparatus which concerns on embodiment of this invention is provided. It is a flowchart which shows the intersection guidance process and T-junction intersection determination process which concern on embodiment of this invention. It is a figure which shows the process example of the front T-junction intersection determination process which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Navigation apparatus, 2 ... Speaker, 3 ... Operation part, 4 ... Display apparatus, 5 ... Vehicle state sensor, 6 ... GPS receiver, 11 ... Memory | storage device, 12 ... Current state calculation part, 13 ... Route search part, 14 ... Memory, 15 ... Audio generator, 16 ... Controller, 17 ... Guide image generator, 18 ... GUI controller.

Claims (6)

A navigation device that performs intersection guidance based on road map data representing a road network shape,
T-junction intersection judging means for judging whether or not the intersection performing the intersection guidance is a T-junction intersection;
Intersection guidance means for performing intersection guidance, including guidance that the intersection is a T-junction when the intersection is a T-junction,
The T-junction intersection judging means has three roads connected to the intersection where the intersection guidance is obtained, which is obtained from the road map data, and is connected to the intersection where the intersection guidance is obtained, which is obtained from the road map data. On three roads, three directions from the intersection where the intersection guidance is performed extend in a T-shape from the intersection where the intersection guidance is performed to three points where the distance from the intersection where the intersection guidance is performed is a predetermined distance. And determining that the intersection performing the intersection guidance is a T-junction intersection. The navigation device according to claim 1,
The T-junction intersection judging means has an angular difference between two directions in the three directions within a range of 180 degrees ± predetermined allowable angle range, and an angular difference with respect to another direction in the remaining one direction. A navigation device characterized in that the three directions extend in a T-shape from an intersection where the intersection guidance is performed when the angle is within an angle range of 90 degrees ± a predetermined allowable angle range. A T-junction intersection determination method for determining whether an intersection is a T-junction intersection based on road map data representing a road network shape,
A first step of determining whether or not there are three roads connected to the intersection based on the road map data;
A second step of determining that the intersection is not a T-junction intersection when it is determined that there are not three roads connected to the intersection;
When it is determined that there are three roads connected to the intersection, based on the road map data, three points on the three roads connected to the intersection that have a predetermined distance from the intersection are A third step of determining whether or not three directions from the intersection extend in a T-shape from the intersection at the obtained three points;
A fourth step for determining that the intersection is not a T-junction intersection when it is determined that the three directions from the intersection do not extend in a T-shape from the intersection to the three determined points;
A fifth step of determining that the intersection is a T-junction when the three directions from the intersection are determined to extend in a T-shape from the intersection to the three determined points; A T-junction intersection determination method characterized by comprising: A method of determining a T-junction intersection according to claim 3,
In the third step, the angle difference between the two directions of the three directions is within a range of 180 degrees ± predetermined allowable angle range, and the angle difference with respect to the other direction of the remaining one direction is 90 degrees ± A T-junction intersection determination method, characterized in that, when the angle is within a predetermined allowable angle range, the three directions are determined to extend in a T-shape from the intersection performing the intersection guidance. A map data creation method for creating road map data representing a road network shape and identification of whether or not each intersection is a T-junction,
A first step of determining whether there are three roads connected to the intersection based on the road network shape;
When it is determined that there are three roads connected to the intersection, based on the road network shape, three points on the three roads connected to the intersection that have a predetermined distance from the intersection are A second step of determining whether or not three directions heading from the intersection to the three determined points extend in a T-shape from the intersection;
When it is determined that the three directions from the intersection extend in a T-shape from the intersection to the three determined points, the map data identifies that the intersection is a T-junction intersection. And a third step of registering to the map data creating method. The map data creation method according to claim 5,
In the second step, the angle difference between the two directions among the three directions is within a range of 180 degrees ± predetermined allowable angle range, and the angle difference with respect to the other direction of the remaining one direction is 90 degrees ± A map data generation method characterized in that, when the angle is within a predetermined allowable angle range, it is determined that the three directions extend in a T shape from the intersection where the intersection guidance is performed.