JP2013205200A - Route guidance system, route guidance device, route guidance method and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a chance of re-searching for an unnecessary route in route guidance.SOLUTION: A route guidance device 200 comprises: a route acquisition section 231 capable of acquiring a route to a destination; and a route guidance section 232 capable of performing route guidance along the route. When a predetermined condition including a condition that a distance, between the route under the route guidance and a present position of a user, is larger than a predetermined distance threshold is satisfied (S40), the route acquisition section 231 can re-acquire the route from the present position to the destination (S80). Also, the route guidance section 200 has a distance threshold acquisition section 233 capable of acquiring the distance threshold depending on the present position of the user (S30).

Description

  The present invention relates to a route guidance system for guiding a route to a destination.

  Conventionally, there is a route guidance device that guides a route to a destination. For example, in a certain prior art, when it is detected that the distance between the current position of the route guidance device that moves with the user and the route being guided is a predetermined value or more, a reroute is performed. Done.

JP 2009-42132 A

  The current position of the route guidance device can be specified by GPS (Gobal Positioning System) using radio waves from an artificial satellite. The accuracy of the current position of the route guidance device specified by the GPS differs depending on the number of satellites that the route guidance device can receive the radio waves and the strength of the radio waves received from each satellite. The GPS provides the accuracy information as well as the current position information. In a certain prior art, the higher the accuracy of the current position, the smaller the threshold value of the distance used as a criterion for determining whether or not the distance between the route being guided and the current position is more than a predetermined value.

  In mountainous areas, there are fewer buildings that are obstructions when receiving satellite radio waves compared to urban areas. For this reason, the detection accuracy of the current position by GPS is high in the mountainous area. As a result, in the above-described prior art, the threshold value of the distance serving as a reference for determining whether or not the distance between the route being guided and the current position is a predetermined value or more is set small. On the other hand, for mountainous areas, the route network data used by the route guidance device for route guidance may not be accurate compared to urban areas. In other words, the actual road position may deviate from the position represented by the road position data held in the route network data. As a result, it may be determined that the distance between the route being guided and the current position is more than a predetermined value, and the reroute may be performed even though the road is actually moving along the route guidance. As a result, the reroute process is performed, and the same route as the route previously guided is guided again. Such a reroute is troublesome for the user and is an unnecessary load for the route guidance device.

  On the other hand, if the distance threshold is set large so that it is difficult to reroute, if the user's current position deviates from the route being guided and enters a different road in an urban area with many roads The reroute will not be performed. Such problems are not limited to the route guidance device using GPS, but route guidance is performed based on the current position and map data, and the route is re-searched when the current position is away from the route being guided. Widely present in the system.

  The present application has been made in order to deal with at least a part of the above-described problems, and an object thereof is to make it difficult to perform an unnecessary route re-search in route guidance.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

1. According to one aspect of the present invention, a route guidance system that provides route guidance is provided. This route guidance system
A route generator that can generate a route to the destination;
A route guide unit capable of performing route guidance along the route,
The route generation unit, when a predetermined condition including that the route where the route guidance is being performed and the current position of the user are separated by a predetermined distance threshold or more is satisfied, from the current position to the object You can generate a route to the ground again,
The route guidance system further includes:
A distance threshold determination unit capable of determining the distance threshold according to the current position of the user;

  With such an aspect, the ease of reacquisition of the route can be changed according to the current position of the user. For example, if the current position is in an area where a road exists at a high density, the distance threshold is determined so that the route can be easily re-acquired, and the current position is located in an area where the road exists at a lower density. If there is, the distance threshold value can be determined so that re-acquisition of the route is less likely to be performed. That is, the ease of reacquisition of the route can be changed according to the situation around the current position. Therefore, it is difficult to re-search unnecessary routes in route guidance.

2. According to another aspect of the present invention, the route guide unit can acquire area map data representing a road included in a predetermined area including the current position.
The distance threshold value determination unit determines the distance threshold value based on the area map data.

  With such an aspect, it is possible to set the ease of reacquisition of the route according to the arrangement state of the road around the current position. In addition, route guidance using the distance threshold can be performed without preparing the distance threshold for all the regions in advance.

3. According to another aspect of the present invention, the area map data is data for outputting a map image having a predetermined size to the user.
The distance threshold value determination unit determines the distance threshold value based on the number of roads included in the area map data and the size of the area represented by the map image.

  According to such an aspect, it is possible to set the ease of reacquisition of the route according to the number of roads around the current position, taking into account the size of the predetermined region to which the region map data corresponds. it can.

4). According to another aspect of the present invention, the area map data is data provided according to a predetermined standard including a scale.
The distance threshold value determination unit determines the distance threshold value based on the number of roads included in the area map data.

  According to such an aspect, the ease of reacquisition of the route can be set according to the number of roads around the current position obtained along a certain reference.

5. According to another aspect of the present invention, the route guidance system further includes a storage unit that stores an original distance threshold value determined for each section on the map in association with the section.
The distance threshold value determination unit determines, as the distance threshold value, the original distance threshold value stored in the storage unit in association with a section including the current position of the user.

  With such an aspect, it is possible to determine the distance threshold value with a lower processing load than in the aspect in which the distance threshold value is determined without depending on the data held in advance.

6). According to still another aspect of the present invention, a method for route guidance is provided. This method
(A) a computer generating a route to the destination;
(B) providing route guidance along the route.
The step (b)
The computer determining a distance threshold according to a user's current location;
When a predetermined condition including that the route on which the route guidance is being performed and the current position are separated by the distance threshold or more is satisfied, a route from the current position to the destination is again determined. And a step generated by the computer.

  Even in such an aspect, the ease of reacquisition of the route can be changed according to the situation around the current position. Therefore, it is difficult to re-search unnecessary routes in route guidance.

7). According to still another aspect of the present invention, a route guidance device that provides route guidance is provided. This route guidance device
A route acquisition unit that can acquire a route to the destination;
A route guide unit capable of performing route guidance along the route.
The route acquisition unit, when a predetermined condition including that the route performing the route guidance and the current position of the user are separated by a predetermined distance threshold or more is satisfied, from the current position to the target The route to go to the ground can be acquired again.
The route guidance device further includes:
A distance threshold acquisition unit capable of acquiring the distance threshold corresponding to the current position of the user;

  Even in such an aspect, the ease of reacquisition of the route can be changed according to the situation around the current position. Therefore, it is difficult to re-search unnecessary routes in route guidance.

  The present invention can be realized in various forms, for example, a route guidance system, a route guidance device and a route guidance method, an information provision system, an information provision device and an information provision method, a route data generation system, and a route. The present invention can be realized in the form of a data generation device and a route data generation method, a computer program for realizing the functions of those systems, devices or methods, a recording medium on which the computer program is recorded, and the like.

The figure which shows the hardware constitutions of the route guidance system which is 1st Example of this invention. The flowchart which shows the flow of the process in the route guidance system of 1st Example. Explanatory drawing which shows the relationship between the route and route position during route guidance, and distance threshold value Dt. The flowchart which shows the acquisition process of the distance threshold value performed by step S30 of FIG. 2 in 2nd Example. The figure which shows the example of the map image data Dm1 of the map image displayed on the display panel 202 when a present position exists in PP11 of FIG. The figure which shows the example of the map image data Dm2 of the map image displayed on the display panel 202 when a present position exists in PP21 of FIG. The figure which shows the map image data Dm1e of the map image displayed on the display panel 202 when the present position exists in PP11 of FIG. The flowchart which shows the acquisition process of the distance threshold value performed by step S30 of FIG. 2 in 3rd Example.

A. First embodiment:
A1. overall structure:
FIG. 1 is a diagram showing a hardware configuration of a route guidance system according to the first embodiment of the present invention. The route guidance system according to the first embodiment includes a route search server 100, a map server 150, and a mobile phone 200.

  The mobile phone 200 includes a GPS unit 201, a display panel 202, an audio output unit 203, a vibration mechanism 204, a communication unit 205, a command input unit 206, a clock unit 209, a main control unit 210, and call control. Part 220.

  The GPS unit 201 is a unit including an antenna for receiving radio waves from a satellite of GPS (Global Positioning System / Global Positioning System). Based on the radio wave received by the GPS antenna, the GPS unit 201 can generate current position information indicating the current position of the mobile phone 200.

  The display panel 202 is a liquid crystal display that can display an image. The voice output unit 203 is a device that includes a speaker, and is a device that can output a message to a user such as route guidance, a melody, and the like by voice. The vibration mechanism 204 is a device that can prompt the user's attention with a predetermined pattern of vibration. In the present specification, the devices 202 to 204 that output images, sounds, and vibrations may be collectively referred to as “output unit”.

  The communication unit 205 can communicate with the route search server 100 and the map server 150 via the Internet INT to transmit and receive information. The command input unit 206 includes a numeric keypad 206a and a cursor key 206b. The user inputs information to the mobile phone 200 via the numeric keypad 206a and the cursor key 206b. The clock unit 209 outputs current time information indicating the current time in response to a request from the main control unit 210. The call control unit 220 is a circuit that performs an incoming call for a call, a voice / electrical signal conversion, and the like.

  The main control unit 210 is a control unit for controlling each unit of the mobile phone 200. The main control unit 210 includes a CPU, a RAM, and a ROM used for those controls. For example, the main control unit 210 controls each unit of the mobile phone 200 by executing the application software 212 with the CPU, obtains route data representing a route from the current position to the destination, and displays the route on the display panel 202. Can be displayed.

  The route search server 100 includes a communication unit 102, a control unit 104, and a storage unit 106. The communication unit 102 can communicate with the map server 150 and the mobile phone 200 via the Internet INT. The storage unit 106 stores route network data for route search. Storage unit 106 further stores data received from map server 150 and mobile phone 200 and data generated based on the data.

  The route network data includes node information and arc information (link information). The node information is data representing points such as an intersection, a point where the number of lanes changes on the road, a place where an approach road to the toll road branches, a start point and an end point of a curve, and a station on the route. The node information includes various attribute information associated with the node. For example, the attribute information of an intersection is information to be displayed on the display panel 202 of the user's mobile phone 200 when the user enters the intersection, for example, information indicating where each road intersecting at the intersection is heading. is there.

  The arc information is information regarding arcs that are roads or route sections between nodes. Each arc is assigned a unique ID. Each arc information includes latitude and longitude data of a number of points included in each arc. That is, roads and route sections for which a route can be set can be represented as a point sequence of those points. Each arc information includes various attribute information associated with the arc in addition to the ID and point sequence information. The arc information includes, for example, attribute information regarding whether or not each arc is a toll road and attribute information on the number of lanes.

  The control unit 104 of the route search server 100 searches for a route based on the information of the departure point and the destination, the waypoint and other search conditions while referring to the route network data stored in the storage unit 106. Then, the control unit 104 generates route data representing a route from the departure point to the destination, and transmits the route data to the mobile phone 200. The route data includes node information, arc information, and various other information.

  The map server 150 includes a communication unit 152, a control unit 154, and a map database 156. The communication unit 152 can communicate with the route search server 100 and the mobile phone 200 via the Internet INT.

  The map database 156 stores map image data transmitted to the mobile phone 200 in order to display a map image on the display panel 202 in the mobile phone 200. The map image data includes vector data representing roads. Based on the data received from the mobile phone 200, the control unit 154 identifies map image data representing a map image of a predetermined size that is a map image requested by the mobile phone 200, and the communication unit 152. To the mobile phone 200.

  Further, the map database 156 stores a distance threshold value that serves as a reference when the mobile phone 200 determines whether or not the current position is away from the route being guided in route guidance. The distance threshold is provided for each section on the map. The section on the map is provided by dividing an area on the map. The map database 156 stores the position information of each section (for example, the position information of the northeast corner of the section and the position information of the southwest corner) and the distance threshold value in association with each other. In this specification, in order to distinguish the distance threshold value stored in the map database 156 from the distance threshold value selected from them and used for the determination in the mobile phone 200, the “original distance threshold value” is used. Sometimes called "value". Based on the data received from the mobile phone 200, the control unit 154 specifies the original distance threshold value of the section including the current position of the mobile phone 200, and transmits it to the mobile phone 200 via the communication unit 152.

A2. Directions:
FIG. 2 is a flowchart showing a process flow of the mobile phone 200 in the route guidance system of the first embodiment. In step S <b> 10, the main control unit 210 of the mobile phone 200 receives destination point information from the user via the command input unit 206. The position information of the destination point can be information that can identify the selected feature as a result of a predetermined search process. Further, the location information of the destination point may be a telephone number that can identify the destination point.

  In step S10 of FIG. 2, the main control unit 210 of the mobile phone 200 then uses the communication unit 205 to transmit the input destination point information (hereinafter also referred to as “destination point information”). Send to. In addition, the mobile phone 200 also transmits the current position information output from the GPS unit 201 to the route search server 100.

  In step S10, the control unit 104 of the route search server 100 identifies the position of the destination point based on the received destination point information. Then, the route from the current position of the user received from the mobile phone 200 to the destination point is searched with reference to the route network data. Then, the route data of the searched route is transmitted to the mobile phone 200 via the communication unit 102. As described above, the cellular phone 200 acquires the route data toward the destination in step S10. The functional unit of the main control unit 210 that performs the process of step S10 is illustrated in FIG. 1 as a route data acquisition unit 231. In addition, a functional unit of the control unit 104 that performs the process of step S10 is illustrated in FIG.

  In step S20 of FIG. 2, the main control unit 210 of the mobile phone 200 performs route guidance. The main control unit 210 of the mobile phone 200 transmits route data received from the route search server 100, current position information obtained from the GPS unit 201, and a map around the current position obtained from the map server 150 by transmitting the current position information. Route guidance is performed based on the image data.

  More specifically, in response to an instruction input from the user via the command input unit 206 of the mobile phone 200, the main control unit 210 of the mobile phone 200 determines the zoom rate of the map image to be displayed on the display panel 202. decide. When there is no instruction from the user, the main control unit 210 of the mobile phone 200 adopts a predetermined zoom rate. Then, the main control unit 210 of the mobile phone 200 transmits the zoom rate to the map server 150 together with the current position information and the information on the orientation of the map to be displayed. The map server 150 determines map image data to be transmitted to the mobile phone 200 based on the current position information, the zoom rate, and the map orientation information, and transmits the map image data to the mobile phone 200 via the communication unit 152. The map image data transmitted to the mobile phone 200 is, for example, a map image centered on the current position, and can display a map image in a specified direction having a requested zoom rate. Image data. A map image having a predetermined size is displayed on the display panel 202 by the map image data.

  The main control unit 210 of the mobile phone 200 is obtained from the map image data around the current position obtained from the map server 150 as described above, the route data received from the route search server 100 in step S10, and the GPS unit 201. Route guidance is performed based on the current position information. More specifically, the main control unit 210 of the mobile phone 200 controls the display panel 202 and the audio output unit 203 to display an image such as a map on the display panel 202 and output audio from the audio output unit 203. Route guidance. A functional unit of the main control unit 210 that performs the process of step S20 is illustrated in FIG. 1 as a route guide unit 232.

  In step S30, the main control unit 210 of the mobile phone 200 transmits the current position information obtained from the GPS unit 201 to the map server 150 via the communication unit 205. Based on the current position information received from the mobile phone 200, the control unit 154 acquires a distance threshold value Dt corresponding to the area including the current position from the map database 156, and transmits the mobile phone 200 via the communication unit 152. Send to. The main control unit 210 of the mobile phone 200 acquires the distance threshold value Dt from the map server 150 via the communication unit 205. The functional unit of the main control unit 210 that performs the process of step S30 is illustrated in FIG. 1 as a distance threshold value acquisition unit 233. In addition, a functional unit of the control unit 154 that performs the process of step S30 is illustrated in FIG. 1 as a distance threshold value determination unit 161.

  In step S40, the main control unit 210 of the mobile phone 200 moves the current position away from the route being guided based on the current position information obtained from the GPS unit 201 and the position information of the route included in the route data. It is determined whether or not the distance is greater than the threshold value Dt. Specifically, the main control unit 210 of the mobile phone 200 calculates the distance of the vertical line dropped from the current position to the route being guided. This distance is the distance between the route being guided and the current position. Then, it is determined whether or not the distance between the route being guided and the current position is more than a distance threshold value Dt. If the distance between the route being guided and the current position is less than the distance threshold value Dt, the process proceeds to step S50. If the distance between the route being guided and the current position is greater than or equal to the distance threshold Dt, the process proceeds to step S80.

  In step S50, the main control unit 210 of the mobile phone 200 determines whether or not the user has reached the destination based on the current position information obtained from the GPS unit 201 and the information on the position of the route included in the route data. Judgment is made. If the user has not reached the destination point, the process returns to step S30 and the route guidance is continued. If the user has reached the destination point, in step S60, the display panel 202 and the audio output unit 203 are controlled to notify the user that the destination point has been reached. Then, the route guidance ends.

  On the other hand, in step S80, the main control unit 210 of the mobile phone 200 transmits the current position information output from the GPS unit 201 to the route search server 100 again to acquire new route data. The control unit 104 of the route search server 100 refers to the route network data based on the destination information obtained from the mobile phone 200 in step S10 and the new current position information obtained from the mobile phone 200 in step S80. The route from the current position of the user to the destination point is searched. Then, the route data of the searched route is transmitted to the mobile phone 200 via the communication unit 102.

  Thereafter, the process returns to step S30, and route guidance is performed on the mobile phone 200. The functional unit of the main control unit 210 that performs the process of step S80 is a route data acquisition unit 231. The functional unit of the control unit 104 that performs the process of step S80 is the route search unit 112.

  FIG. 3 is an explanatory diagram showing the relationship between the route during route guidance, the current position, and the distance threshold value Dt. As described above, the map database 156 of the map server 150 holds the distance threshold value Dt for each predetermined section on the map. In FIG. 3, the example of the division on a map is shown by A11-A43. In the example of FIG. 3, the sections A11 to A43 are square sections. And distance threshold value Dt matched with each division A11-A43 is shown in the lower right of division A11-A43. The distance threshold value Dt of the section A41 is 10 m. The distance threshold Dt of the other sections A11 to A33, A42, A43 is 25 m.

  The distance threshold value Dt for each section is determined in advance according to the number of roads included in each section. In FIG. 3, roads are indicated by R0 to R10. The lower right side of the area shown in FIG. 3 is an urban area, and there are many roads. On the other hand, the upper left side of the area shown in FIG. 3 is a mountainous area, and the number of roads is small. For this reason, the distance threshold value Dt of the section A41 having a larger number of roads is set to be smaller than the distance threshold value Dt of the sections A11 to A33, A42, and 43.

  In the example of FIG. 3, it is assumed that the route that is the target of route guidance includes the road R0. In FIG. 3, a position away from the route R0 by the distance threshold Dt = 10 m in the section A41 is indicated by a broken line DtL1. A position that is separated from the route R0 by the distance threshold Dt = 25 m of the sections A11 to A33, A42, 43 is indicated by a one-dot chain line DtL2. In order to facilitate understanding of the technology, the position DtL1 that is 10 m away from the route R0 and the position DtL2 that is 25 m away from the route R0 show only a part.

  For example, in the process of steps S20 to S80 in FIG. 2, it is assumed that the user is guided along a route along the road R0 and progressing. An example of the current position of the user is indicated by PP0 (see the lower left in FIG. 3). Thereafter, it is assumed that the user leaves the guided route R0 and enters the road R2. When the current position of the user is at the position PP11 included in the section A41, the distance threshold value Dt obtained in step S30 in FIG. 2 is 10 m (see the lower right of the section A41). When the current position of the user is at the position PP11, the current position of the user is not separated from the route R0 by the distance threshold value Dt (10 m) or more. Therefore, the determination in step S40 in FIG. 2 is No, and the route guidance along the route R0 is continued (see steps S50 and S20).

  Thereafter, even when the current position of the user reaches the position PP12, the distance threshold value Dt obtained in step S40 of FIG. 2 is 10 m (see the lower right of the section A41). When the current position of the user is at the position PP22, the current position of the user is separated from the route R0 by a distance threshold value Dt (10 m) or more. Therefore, the determination in step S40 in FIG. 2 is Yes, and the route data is reacquired (step S80).

  On the other hand, it is assumed that the user leaves the guided route R0 and enters the road R1 (see the upper part of FIG. 3). When the current position of the user is at the position PP21, the distance threshold value Dt obtained in step S40 in FIG. 2 is 25 m (see the lower right of the section A22). When the user's current position is at the position PP21, the user's current position is not separated from the route R0 by the distance threshold value Dt (25m) or more. Therefore, the determination in step S40 in FIG. 2 is No, and the route guidance along the route R0 is continued (see steps S50 and S20).

  Even when the current position of the user is at the position PP22, the distance threshold value Dt obtained in step S40 of FIG. 2 is 25 m (see the lower right of the section A22). The current position of the user is 10 m or more away from the route R0, but not more than the distance threshold value Dt (25 m). Therefore, the determination in step S40 of FIG. 2 is No, and the route guidance along the route R0 is continued (steps S50 and S20).

  Thereafter, when the current position of the user reaches the position PP23, the position PP23 is included in the section A12, and therefore the distance threshold value Dt obtained in step S40 of FIG. 2 is 25 m (see the lower right of the section A12). When the current position of the user is at the position PP23, the current position of the user is separated from the route R0 by a distance threshold value Dt (25m) or more. Therefore, the determination in step S40 in FIG. 2 is Yes, and the route data is reacquired (step S80).

  In the present embodiment, the distance threshold value Dt that serves as a reference for determining whether or not to re-search for a route is determined according to the current position. For this reason, it is possible to determine the ease of re-searching for the route by reflecting the situation around the current position. For this reason, compared with the mode in which the distance threshold value Dt is determined based on the current position, unnecessary re-search is difficult to perform, and necessary re-search is easily performed.

  More specifically, in this embodiment, the distance threshold value Dt in the mountainous areas A11 to A23 and the like is set to a larger value (25 m) than the distance threshold value Dt in the urban area A41 (see FIG. 3). For this reason, in mountainous areas where the position information of roads in the route network data is more likely to be inaccurate than in urban areas, even though the roads that are being routed are traveling accurately, There is a low possibility that re-acquisition (step 80 in FIG. 2) will be performed.

  In the present embodiment, the distance threshold value Dt in the urban area A41 is set to a smaller value (10 m) than the distance threshold value Dt in the mountainous areas A11 to A23 (see FIG. 3). For this reason, when the road departs from the route being guided and the user enters a different route in an urban area, the route can be quickly reacquired. As a result, the distance threshold Dt is constant regardless of the location, and the increase in the distance from the original route in the reacquired route can be reduced compared to the case where the reacquisition of the route is delayed.

  In this embodiment, a distance threshold value Dt for determining whether or not to reacquire the route is determined in advance according to the area on the map (see FIG. 3). For this reason, compared with the aspect which calculates the distance threshold value Dt for every determination, the processing load of a system can be made small. As a result, the system can be simplified. Also, assuming the same level of processing capability, the response of the system to the user's operation can be made quicker than the mode of calculating the distance threshold value Dt for each determination.

  Note that “route search server 100”, “map server 150”, and “mobile phone 200” in the present embodiment correspond to “route guidance system” in “means for solving problems”. The “route data acquisition unit 231” and the “route search unit 112” correspond to the “route generation unit”. The route guide unit 232 corresponds to a “route guide unit”. The “distance threshold value acquisition unit 233” and the “distance threshold value determination unit 161” correspond to the “distance threshold value determination unit”. The “map database 156” corresponds to a “storage unit”.

  In addition, the “mobile phone 200” in the present embodiment corresponds to the “route guidance device” in the “means for solving the problem”. The “route data acquisition unit 231” corresponds to the “route acquisition unit”. The “distance threshold acquisition unit 233” corresponds to the “distance threshold acquisition unit”.

B. Second embodiment:
In the route guidance system of the first embodiment, the distance threshold is determined in advance for each predetermined section on the map and stored in the map database 156 (see FIG. 3). However, in the second embodiment, the distance threshold is determined based on the map image data that the mobile phone 200 receives from the map database 156. That is, in the second embodiment, the process of step S30 in FIG. 2 is different from that of the first embodiment. The other points of the second embodiment are the same as those of the first embodiment.

  FIG. 4 is a flowchart showing the distance threshold value acquisition process executed in step S30 of FIG. 2 in the second embodiment. In step S310, the main control unit 210 of the mobile phone 200 calculates the number of roads included in the map image data from the map image data around the current position. The map image data around the current position is map image data acquired for display on the display panel 202 at the time of route guidance in step S20 of FIG. The map image data includes vector data representing roads. The main control unit 210 of the mobile phone 200 calculates the number of roads included in the map image data around the current position based on vector data representing roads.

  FIG. 5 is a diagram illustrating an example of map image data Dm1 of a map image displayed on the display panel 202 when the current position is PP11 in FIG. It is assumed that the map image is displayed on the display panel 202 so that the north is on the top. The area indicated by the map image data Dm1 includes ten roads R0, R2 to R10. Therefore, when the current position is PP11 in FIG. 3 and the map image of the map image data Dm1 is displayed on the display panel 202, the number N of roads acquired in step S310 in FIG. 4 is ten.

  FIG. 6 is a diagram illustrating an example of map image data Dm2 of a map image displayed on the display panel 202 when the current position is at PP21 in FIG. The area indicated by the map image data Dm2 includes two roads R0 and R1. Therefore, when the current position is at PP21 in FIG. 3 and the map image of the map image data Dm2 is displayed on the display panel 202, the number N of roads acquired in step S310 in FIG. 4 is two.

  FIG. 7 is a diagram showing map image data Dm1e of a map image displayed on the display panel 202 when the current position is PP11 in FIG. The map image data Dm1e in FIG. 7 has a different zoom ratio from the map image data Dm1 in FIG. That is, the map image data Dm1e in FIG. 7 is map image data that displays a map image that is enlarged as compared with the map image data Dm1 in FIG. For reference, in FIG. 7, the range indicated by the map image of the map image data Dm1 in FIG. 5 is indicated by a one-dot chain line. On the other hand, in FIG. 5, the range indicated by the map image of the map image data Dm1e in FIG.

  The area indicated by the map image data Dm1e does not include the roads R6 and R7 included in the area indicated by the map image data Dm1. The area indicated by the map image data Dm1e includes eight roads R0, R2 to R5, R8 to R10. Therefore, when the current position is PP11 in FIG. 3 and the map image of the map image data Dm1e is displayed on the display panel 202, the number N of roads acquired in step S310 in FIG. 4 is eight.

In step S320 of FIG. 4, the main control unit 210 of the mobile phone 200 calculates the road number parameter Pr based on the number of roads N acquired in step S310 and the zoom rate S of the map image data around the current position. To do. Note that the zoom rate S of the map image data is determined according to an instruction or the like input from the user via the command input unit 206 of the mobile phone 200 in step S20 of FIG. When a map image is displayed on the display panel 202 at a scale of 1 / S, the zoom factor is S. The road number parameter Pr is obtained, for example, by dividing the zoom factor S by the number of roads N acquired in step S310.
Pr = S / N (1)

For example, in the examples of FIGS. 5 and 6, assuming that the zoom rate S is 25000, that is, the scale of the map image is 1/25000, the road number parameters Pr1 and Pr2 in the examples of FIGS. become that way.
Pr1 = 25000/2
= 12500 (2)
Pr2 = 25000/10
= 2500 (3)

Further, in the example of FIG. 7, if the zoom rate S is 20000, that is, the scale of the map image is 1/20000, the road number parameter Pr3 in the example of FIG. 7 is as follows.
Pr3 = 20000/8
= 2500 (4)

In step S330 of FIG. 4, the main control unit 210 of the mobile phone 200 determines the distance threshold value Dt from the road number parameter Pr. The distance threshold value Dt can be determined, for example, by multiplying the road number parameter Pr by a predetermined coefficient C. C can be 0.002, for example.
Dt = C × Pr (5)

The distance threshold values Dt1, Dt2, and Dt3 in the examples of FIGS. 5, 6, and 7 are as follows.
Dt1 = 0.002 × 12500
= 25 (6)
Dt2 = 0.002 × 2500
= 5 (7)
Dt3 = 0.002 × 2500
= 5 (8)

  In the second embodiment, the distance threshold value Dt is determined based on the map image data around the current position as described above. In the above, the processing content has been described by taking the case where the current position is at the positions PP11 and PP21 as an example, but the distance threshold value Dt is determined by the same processing when the current position is at another position.

  In the first embodiment, the distance threshold value Dt is constant while the current position is in the same section, and changes in a staircase pattern when the current position crosses the boundary of the section (see FIG. 3). On the other hand, in the second embodiment, the distance threshold value Dt is determined more finely in accordance with the movement of the current position, reflecting the road layout around the current position (see FIG. 7). Therefore, according to the second embodiment, it is possible to reduce unnecessary reroute when the current position is in an area with few roads, and to secure necessary reroute when the current position is in an area with many roads. The accuracy can be controlled.

  In the second embodiment, the distance threshold value Dt is determined based on map image data for displaying a map image on the display panel 202 (see step S310 in FIG. 4). For this reason, compared with the aspect which performs additional data communication in order to determine the distance threshold value Dt, data communication amount can be decreased.

  Further, in the second embodiment, the distance threshold Dt is determined in consideration of the zoom rate of the map image data, that is, the size of the area represented by the map image data (see step S320 in FIG. 4). For this reason, when the distance threshold value Dt is determined based on the map image data, the fluctuation width of the distance threshold value Dt that can vary depending on the scale of the map image displayed on the display panel 202 by the user is reduced. (See formulas (7) and (8)).

  The “map image data” in the present embodiment corresponds to “region map data” in “means for solving the problem”.

C. Third embodiment:
In the second embodiment, the distance threshold value Dt is determined using the map image data around the current position acquired for display on the display panel 202 (see S310 in FIG. 4). Since the map image displayed on the display panel 202 can have various scales, the distance threshold Dt is determined in consideration of the scale of the map image (see S320). However, in the third embodiment, the distance threshold Dt is determined based on the reference map data having a common scale and indicating the map of the area including the current position. That is, in the third embodiment, the process of step S30 in FIG. 2 is different from the first embodiment and the second embodiment. The other points of the third embodiment are the same as those of the first embodiment.

  FIG. 8 is a flowchart showing the distance threshold value acquisition process executed in step S30 of FIG. 2 in the third embodiment. In step S305, the main control unit 210 of the mobile phone 200 acquires reference map data around the current position from the map server.

  The reference map data is map image data that is generated according to a single reference among the map image data held by the map database 156 of the map server 150 and represents a reference scale map image. The map image data generation standard includes, for example, a standard regarding a road expression method, such as what kind of road is omitted and how intersections and ramps are expressed. The reference scale can be set to 1/25000, for example.

  In step S305, the main control unit 210 of the mobile phone 200 transmits the current position information to the map server 150 and requests reference map data. The map server 150 determines reference map data according to a predetermined reference according to the current position information, and transmits the reference map data to the mobile phone 200 via the communication unit 152. The predetermined reference is, for example, the relationship between the range to be included in the map of the reference map data transmitted to the mobile phone 200 and the current position (for example, a square range of 100 m in each of east, west, south, and north with the current position as the center). It is.

  In step S315, the main control unit 210 of the mobile phone 200 calculates the number of roads included in the reference map data from the acquired reference map data around the current position. Since the reference map data is also map image data, it includes vector data representing a road. The main control unit 210 of the mobile phone 200 calculates the number of roads included in the reference map data around the current position based on vector data representing roads.

In step S325, the main control unit 210 of the mobile phone 200 determines the distance threshold value Dt from the number N of roads acquired in step S315. The distance threshold value Dt can be determined, for example, by dividing the predetermined coefficient C2 by the number N of roads. C2 may be 50, for example.
Dt = C2 / N (9)

  In the third embodiment, the distance threshold value Dt is determined based on the reference map data around the current position as described above.

  Also in the third embodiment, as in the second embodiment, compared to the first embodiment, unnecessary reroute is reduced when the current position is in an area with few roads, and the current position is in an area with many roads. Ensuring the necessary reroute at the time can be controlled with higher accuracy.

  In the third embodiment, the distance threshold value Dt is determined based on reference map data having the same scale and generated along a single reference (see step S305 in FIG. 8). . Therefore, the distance threshold Dt to be determined is displayed on the display panel 202 as in the aspect in which the distance threshold Dt is determined based on the map image data for displaying the map image on the display panel 202. (Scale, orientation, etc.) are not affected.

  The “reference map data” in the present embodiment corresponds to “region map data” in “means for solving the problem”.

D. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

D1. Modification 1:
In the description of the above embodiment, it has been described that the route is searched again when the current position is away from the route being guided by the distance threshold Dt or more (see step S40 in FIG. 2). In the determination in step S40, “Yes” may be determined by detecting once that the current position is away from the route being guided by the distance threshold value Dt or more. The determination of “Yes” may be made by detecting that the current position is more than the distance threshold value Dt from the route in the middle by continuously detecting a plurality of times (for example, 10 times).

  The current position may be detected with accuracy information. In that case, after the distance threshold value is once determined according to the current position, the distance threshold value may be further increased or decreased according to the detection accuracy of the current position. In addition, since the current position is more than the distance threshold value Dt from the route being guided, the current position is detected with high accuracy in response to the determination of “Yes” by continuously detecting multiple times. In such a case, the number of thresholds can be reduced, and when the detection accuracy of the current position is lower, the number of thresholds can be increased. Further, the condition for re-searching the route may include a condition that the detection accuracy of the current position is higher than a predetermined level, in addition to the current position being more than the distance threshold. In other words, the conditions for re-searching the route include other conditions such as a condition regarding the detection accuracy of the current position and the topography around the current position, in addition to the current position being away from the route being guided by the distance threshold Dt or more. Can be included.

D2. Modification 2:
In the first embodiment, the “division” in which the distance threshold value Dt is determined in association with each other can be determined, for example, by dividing the land of a certain country. This section is preferably arranged on the map without any gaps. However, the “division” does not have to be provided for the entire country. For example, in a region where no road exists, it is not necessary to provide a “section” that is determined in association with the distance threshold value Dt.

D3. Modification 3:
In the above embodiment, the acquisition of the distance threshold value Dt (step S30 in FIG. 2) is performed separately from the acquisition of the map image data (step S20). However, the acquisition of the map image data and the request and acquisition of the distance threshold value Dt may be performed by a single transmission request with the current position information. Prior to the route guidance at step S20, the distance threshold value at step S30 may be determined.

D4. Modification 4:
In the second embodiment, the distance threshold value Dt is obtained by multiplying the number N of roads by the coefficient C and dividing the zoom rate S (see the above formulas (1) and (5)). However, the distance threshold value Dt can also be determined by other methods. For example, the predetermined coefficient C3 is determined according to the zoom ratio category (for example, 1/3000 or more and less than 1/5000, 1/5000 or more and less than 1/10000, etc.), and the distance is determined based on the coefficient C3. The threshold value Dt may be determined. Similarly, a predetermined coefficient C4 is determined according to the number of roads (0, 1, 3-4, 4-7, etc.), and a distance threshold Dt is determined based on the coefficient C4. You may be made to do.

  However, when the distance threshold value Dt is determined using map data for outputting a map image of a predetermined size to the user, the zoom rate of the map image, that is, the region size indicated by the map image It is preferable to determine the distance threshold value Dt according to the number of roads included in the map image. If the other conditions are the same, the distance threshold value Dt is preferably determined such that the distance threshold value Dt increases as the zoom factor S increases. Further, if other conditions are the same, it is preferable to set the distance threshold Dt so that the distance threshold Dt decreases as the number N of roads increases. Here, “the larger A is, the larger B is” means that “when A increases, B increases or does not change”. Further, “the larger A is, the smaller B is” means “when A increases, B decreases or does not change”.

However,
The distance threshold is calculated based on the number of roads included in the area map data for outputting a map image to the user and the scale of the area represented by the area map data with respect to the actual area. It is preferable to calculate a parameter corresponding to the number of roads and determine a distance threshold according to the parameter. If the size of the image when the map image is output to the user is constant, the parameters corresponding to the number of roads per unit area are the number of roads included in the area map data, and the area It can be calculated based on the size of the area represented by the map data.

D5. Modification 5:
In the third embodiment, the reference scale is 1/25000. However, the reference scale may be other numerical values such as 1/1500 or 1/5000. That is, the reference scale that is the scale of the reference map data, the reference zoom rate that is the zoom ratio of the reference map data transmitted to the terminal, or the size of the map display area of the reference map data transmitted to the terminal is arbitrarily set. Can be determined.

  In the third embodiment, the relationship between the range to be included in the map of the reference map data transmitted to the mobile phone 200 and the current position is a square range of 100 m from the current position to the east, west, south, and north. . However, the relationship between the range to be included in the map of the reference map data and the current position may be another relationship. For example, the range to be included in the map of the reference map data may be a rectangular range such as 100 m in the east and west with respect to the current position and 150 m in the north and south, for example. Further, the traveling direction of the user may be a long side direction, and the left and right direction may be a rectangular range having the same dimensions.

D6. Modification 6:
In the above embodiment, the distance threshold is determined according to the density of the road around the current position of the user. However, the distance threshold value that is a criterion for determining whether or not to re-search for the route is information around the current position, and can be determined based on information other than the density of the road. For example, the distance threshold value can be reduced when the branch angle of the branch road on the route around the current position is small, and the distance threshold value can be increased when the branch angle is larger. . Further, the distance threshold value can be reduced when the number of intersections on the route around the current position is small, and the distance threshold value can be increased when the number of intersections is larger.

D7. Modification 7:
In the above embodiment, the destination information is not transmitted from the mobile phone 200 to the route search server 100 in the route re-search in step S80 of FIG. And
The control unit 104 of the route search server 100 searches for a route based on the destination point information obtained from the mobile phone 200 in step S10 and the new current position information obtained from the mobile phone 200 in step S80. However, when re-searching the route, both the destination information and the current position information may be transmitted from the mobile phone 200 to the route search server 100.

D8. Modification 8:
In the above-described embodiment, a mode in which GPS is used to obtain current position information has been described. However, the current position information is generated by GLONASS (Global Navigation Satellite System), satellite positioning systems other than GPS, such as Galileo (in other words, Global Navigation Satellite System (GNSS)). It may be. In addition, for example, when the terminal carried by the user is a mobile phone, the location information is generated based on the distance between the base station and the mobile phone obtained based on the strength of the radio wave between the mobile phone and the base station , You may go. In such an aspect, the terminal carried by the user may be an aspect that does not include the global navigation satellite system receiver. Furthermore, the component that generates the position information in the mobile terminal carried by the user may be a mode in which a plurality of methods, for example, a method using a satellite positioning system and a method using a mobile phone base station are used in combination. it can.

  In other words, the component that generates location information in the mobile terminal can be based on any principle or system operated by any institution as long as the current location information can be specified. Good.

D9. Modification 9:
Map image data as image data stored in the map database 156 of the map server 150 may be stored as raster data or may be stored as vector data. The map image data transmitted to the mobile phone 200 as a terminal device carried by the user may be raster data or vector data. Further, one of the map image data in the map database 156 and the map image data transmitted to the terminal device can be vector data and the other can be raster data. Any map image data can include both raster data and vector data. However, when the map image data transmitted to the terminal device is data that constitutes a map image only by raster data, when the number of roads is acquired based on the map image data (step S310 in FIG. 4, FIG. 8 step S315), it is preferable to obtain the number of roads using an image recognition technique.

D10. Modification 10:
In the above embodiment, in step S10 in FIG. 2, a route from the current position transmitted from the mobile phone 200 to the destination point is searched. However, instead of the current position at that time, a route from the reference position designated by the user to the destination point or the destination area may be searched. That is, a route used for route guidance and its candidate can be a route from a certain point to a destination point or a destination area.

D11. Modification 11:
In the above embodiment, the route guidance system includes the route search server 100, the map server 150, and the mobile phone 200 as its components. However, a mode in which the functions of the route search server 100 and the map server 150 are provided in a portable terminal that can be carried by the user, can acquire the current position, and can perform a predetermined output to the user can also be adopted. Further, the route search server 100 and the map server 150 may be the same server. Note that the portable terminal may be a PDA (Personal Data Assistant), a notebook computer, or the like as a device that does not have a telephone function. That is, the mobile terminal may be any device that can be carried by the user and can perform a predetermined output to the user based on the data.

  That is, the route guidance system as a guidance device may be one device in which each component is housed in one housing. The route guidance system can also be configured as two or more devices whose constituent elements are connected to each other via a data communication line. For each function such as a function for generating route data and a function for selecting a target area, one or more arbitrary functions can be assigned to each device. Each function may be realized by one device, or two or more devices may be realized in cooperation. In an aspect in which two or more components are connected by a communication line, the output unit that outputs information to the user is preferably carried by the user.

D12. Modification 12:
In the above embodiment, the route search server 100, the map server 150, and the mobile phone 200 can be realized as a computer having predetermined hardware for performing the above functions. In the above embodiment, a part of the configuration realized by hardware may be replaced with software, and conversely, a part of the configuration realized by software may be replaced by hardware. For example, a part of the function of the application software 212 (FIG. 1) can be executed by the control circuit.

  A computer program that realizes such a function is provided in a form recorded on a computer-readable recording medium such as a magnetic disk or a CD-ROM. The host computer reads the computer program from the recording medium and transfers it to the internal storage device or the external storage device. Alternatively, the computer program may be supplied from the program supply device to the host computer via a communication path. When realizing the function of the computer program, the computer program stored in the internal storage device is executed by the microprocessor of the host computer. Further, the host computer may directly execute the computer program recorded on the recording medium.

  In this specification, the host computer is a concept including a hardware device and an operation system, and means a hardware device that operates under the control of the operation system. The computer program causes such a host computer to realize the functions of the above-described units. Note that some of the functions described above may be realized by an operation system instead of an application program.

  In the present invention, the “computer-readable recording medium” is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but an internal storage device in a computer such as various RAMs and ROMs, An external storage device fixed to a computer such as a hard disk is also included.

DESCRIPTION OF SYMBOLS 100 ... Route search server 102 ... Communication part 104 ... Control part 106 ... Memory | storage part 112 ... Route search part 150 ... Map server 152 ... Communication part 154 ... Control part 156 ... Map database 200 ... Mobile phone 201 ... GPS unit 202 ... Display panel DESCRIPTION OF SYMBOLS 203 ... Voice output part 204 ... Vibration mechanism 205 ... Communication part 206 ... Command input part 206a ... Numeric keypad 206b ... Cursor key 209 ... Clock part 210 ... Main control part 212 ... Application software 220 ... Call control part 231 ... Path | route data acquisition part 232 ... route guidance part A11-A43 ... division associated with distance threshold C, C2 ... coefficient Dm1 ... map image data of map image displayed when current position is in PP11 Dm1e ... when current position is in PP11 Map image data of the displayed map image Dm2 ... Map image data of a map image displayed when the current position is at PP21 DtL1 ... A position 10m away from the route R0 DtL2 ... A position 25m away from the route R0 INT ... Internet PP11, PP12, PP21, PP22, PP23 ... Examples of current location R0-R10 ... Road

Claims (8)

A route guidance system that provides route guidance,
A route generator that can generate a route to the destination;
A route guide unit capable of performing route guidance along the route,
The route generation unit, when a predetermined condition including that the route where the route guidance is being performed and the current position of the user are separated by a predetermined distance threshold or more is satisfied, from the current position to the object You can generate a route to the ground again,
The route guidance system further includes:
A route guidance system comprising a distance threshold value determination unit capable of determining the distance threshold value according to the current position of the user. The route guidance system according to claim 1,
The route guide unit can acquire area map data representing a road included in a predetermined area including the current position,
The distance threshold determination unit is a route guidance system that determines the distance threshold based on the area map data. The route guidance system according to claim 2,
The area map data is data for outputting a map image of a predetermined size to the user,
The distance threshold determination unit determines the distance threshold based on the number of roads included in the region map data and the size of the region represented by the map image. The route guidance system according to claim 2,
The area map data is data provided in accordance with a predetermined standard including a scale,
The distance threshold determining unit determines the distance threshold based on the number of roads included in the area map data. The route guidance system according to claim 1, further comprising:
A storage unit that stores an original distance threshold value determined for each section on the map in association with the section;
The distance threshold determination unit determines the original distance threshold stored in the storage unit in association with a section including the current position of the user as the distance threshold. Guidance system. A method of route guidance,
(A) a computer generating a route to the destination;
(B) providing route guidance along the route,
The step (b)
The computer determining a distance threshold according to a user's current location;
When a predetermined condition including that the route on which the route guidance is being performed and the current position are separated by the distance threshold or more is satisfied, a route from the current position to the destination is again determined. A route generating method comprising: a computer generating step; A computer program for route guidance using a computer,
The ability to generate a route to the destination,
A function of performing route guidance along the route;
Is a computer program for causing the computer to realize
The function of performing the route guidance is as follows:
The ability to determine a distance threshold according to the user's current location;
When a predetermined condition including that the route on which the route guidance is being performed and the current position are separated by the distance threshold or more is satisfied, a route from the current position to the destination is again determined. A computer program including a function to generate. A route guidance device that provides route guidance,
A route acquisition unit that can acquire a route to the destination;
A route guide unit capable of performing route guidance along the route,
The route acquisition unit, when a predetermined condition including that the route performing the route guidance and the current position of the user are separated by a predetermined distance threshold or more is satisfied, from the current position to the target You can get the route to the ground again,
The route guidance device further includes:
A route guidance device comprising a distance threshold value acquisition unit capable of acquiring the distance threshold value according to the current position of the user.

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