JP2013019849A - Route search system, route search method and route search program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a route search system capable of reducing the possibility to select a route which runs a segment identical to a previously set route as an initial route.SOLUTION: The route search system obtains a piece of information on an existing route which represents a previously set route R from a present point P to a destination G. A segment from the present point P to a point away therefrom by a specified distance dcloser to the destination G is specified as a specified segment D. A segment, which begins from the first intersection viewed from the present point P as the start intersection I, is set as a first bypass segment Q. A correction ratio for correcting the route search cost for searching the first bypass segment Q is set as a first correction ratio for increasing route search cost. A correction ratio for correcting the route search cost for searching a second bypass segment W which is a segment excluding the first bypass segment Q in the specified segment D is set as a second correction ratio which is smaller than the first correction ratio and which increases the route search cost. The route search costs for establishing links with the first bypass segment and the second bypass segment respectively are corrected based on the first correction ratio and the second correction ratio. A route which corresponds to link group which minimizes the sum of the route search cost is selected.

Description

  The present invention relates to a route search system, a route search method, and a route search program.

  A technique is known in which a larger correction factor is set for a detour section on a route than other sections, and a route is re-searched based on a route search cost corrected according to the correction factor (see Patent Document 1, Reference). .) Since the route search cost for the detour section is increased by a correction factor larger than that of other sections, the route can be re-searched so as to detour the detour section. In Patent Document 1, since the user can designate the distance of the detour section, it is possible to re-search for a detour route with respect to a range according to the user's desire.

Japanese Patent No. 30605978

  In many cases, when a user is dissatisfied with an existing route due to a traffic jam or the like, the user re-searches the route. However, in Patent Document 1, a road that is scheduled to travel next to a road that is currently traveling even after re-searching (hereinafter, referred to as a next planned driving road) is adopted as a constituent section of a route after re-searching. There was a problem. That is, despite the re-searching of the route, there is a problem that the user cannot be satisfied with the route after the re-search by being guided to the next scheduled road to be driven before the correction at the next intersection. Such a problem arises because the route search cost for the next scheduled road is not sufficiently high. In this specification, the road refers to a road section where the start point and the end point are intersections, and corresponds to a link on map information. On the other hand, a section also refers to a road section, but the start point and end point of the section are not necessarily an intersection, and the section does not necessarily correspond to a link on map information.

  One of the reasons why the route search cost for the next scheduled road is not sufficiently high is that the next scheduled road is short (the distance to the next intersection is short). Since the route search cost is proportional to the length of the road, even if the route search cost is greatly corrected by including the entire next planned road in the detour section, if the next planned road is short, The route search cost is not large enough. In this case, a route for exiting to a road different from the existing route at the next intersection via the next scheduled road can be searched again. In particular, if the next planned road is short, the route search cost for the lane and the opposite lane of the next planned road will also be low, so it will pass through the next planned road at the next intersection on the opposite side of the next planned road. The route search cost that increases by making a U-turn to the lane is also reduced. Therefore, there is a case where a route that makes a U-turn to the opposite lane of the next scheduled road is re-searched, and the user is greatly dissatisfied with the re-searched route.

Another reason why the route search cost for the next scheduled road does not increase sufficiently is that the detour section has ended at a position close to the first intersection, even if the next scheduled road is long. Can be mentioned. That is, since the section overlapping with the detour section in the next scheduled road is shortened, the route search cost for the next scheduled road is not sufficiently increased even if the route search cost is corrected to be large for the overlapping section. In particular, in the case of cited document 1, since the distance of the detour section is designated by the user, when the distance of the detour section is designated short by the user, the section overlapping the detour section on the next scheduled road is likely to be short.
The present invention has been made in view of the above problems, and an object of the present invention is to reduce the possibility of searching for a route that travels the same section as an existing route after passing through an intersection that reaches first.

  In order to achieve the above object, in the route search system of the present invention, the existing route information acquisition means acquires existing route information indicating an existing route that is a route from the current location to the destination location. The designated section setting means sets, as the designated section, a section from the current point on the existing route to a point that has traveled to the destination point side by a designated distance designated by the user. The first detour section setting means sets the section on the existing route starting from the starting point intersection that is the first intersection from the current point on the existing route as the first detour section. The first correction factor setting means sets the correction factor for correcting the route search cost for the first bypass section to the first correction factor that increases the route search cost. Further, the second correction rate setting means sets the correction rate for the second bypass section, which is a section excluding the first bypass section among the specified sections, smaller than the first correction ratio and increases the route search cost. Set to 2 correction factor. That is, the second correction factor for increasing the route search cost is set for the second bypass segment, but the first correction factor for the first bypass segment is set larger than the second correction factor for the second bypass segment. Then, the route search means corrects the route search cost for the link corresponding to each of the first detour section and the second detour section based on the first correction rate and the second correction rate, respectively. The route corresponding to the link group that minimizes the sum is searched as a correction route of the existing route. That is, the route search cost for the second bypass section is corrected so as to increase by the second correction factor, and the route search cost for the first bypass segment is increased by the first correction factor that is greater than the second correction factor. to correct. Then, a route corresponding to the link group that minimizes the route search cost corrected by the first correction factor and the second correction factor is searched for as a correction route of the existing route.

  In the above configuration, the first detour section starting from the starting point intersection on the existing route has the same starting point as the road scheduled to travel after passing the starting point intersection on the existing route (hereinafter referred to as the next scheduled driving road). . That is, at least a part of the first detour section and the next planned road to travel have an overlapping relationship. This relationship is maintained no matter how the specified distance is specified by the user. Therefore, the first correction factor setting means sets the first correction factor that increases the route search cost for the first detour section that overlaps at least partly with the next scheduled driving road, so that the next scheduled driving road regardless of the designated distance. Can be increased by the first correction factor. Therefore, it is possible to reduce the possibility that the link corresponding to the next scheduled road will be adopted as the component link of the corrected route. Here, the route search cost of the link is proportional to the length of the road corresponding to the link. For example, the road length, the number of lanes, the congestion degree, the average moving speed, etc. are multiplied by the road length. Is obtained. Accordingly, the shorter the next scheduled road, the lower the route search cost for the link corresponding to the next scheduled road. However, by setting a first correction factor that is larger than the second correction factor for the next scheduled road that overlaps with the first detour section, even if the length of the next scheduled road is short, it corresponds to the next scheduled road. A large route search cost for the link can be secured. Therefore, even if the length of the next scheduled road is short, it is possible to reduce the possibility that the link corresponding to the next scheduled road is adopted as the constituent link of the corrected route.

  On the other hand, for the second bypass section excluding the first bypass section from the specified section that is the section from the current position to the destination that has traveled to the destination point by the specified distance specified by the user on the existing route, the second correction factor This increases the route search cost. For the first detour section, since a first correction factor for increasing the route search cost is set separately, the correction factor (first factor) for increasing the route search cost for the entire designated section having the designated distance designated by the user. 1 correction rate, 2nd correction rate) can be set. Therefore, it is possible to reduce the possibility that the link corresponding to the designated section having the designated distance designated by the user is adopted as the constituent link of the correction route. That is, it is possible to search for a corrected route that bypasses the existing route for the range specified by the user. In addition, by setting a second correction factor smaller than the first correction factor for the second bypass segment without setting the first correction factor for both the first bypass segment and the second bypass segment, the total route search cost The adverse effect of excessively increasing can be prevented.

  When a specified distance shorter than the distance from the current point to the starting point intersection is specified on the existing route, the end point of the specified section is closer to the current point than the starting point of the first detour section, and the specified section and the first detour It will not overlap with the section. In this case, the second bypass section obtained by removing the first bypass section from the specified section is the specified section itself. In this case, the end point of the designated section is closer to the current point than the start point of the first detour section. That is, the entire designated section (second detour section) exists in a section that cannot be detoured until the starting point intersection is reached from the current point, and the second correction factor is set for the second detour section. The Rukoto. Even in such a case, since the first correction factor is set for the first detour section starting from the starting point intersection, the next planned road to be traveled is the corrected route no matter how the specified distance is specified by the user. The possibility of being adopted as a constituent section can be reduced.

  The existing route information acquisition unit may acquire existing route information indicating an existing route from the current point to the destination point, and the existing route may be a currently guided route. The existing route may be a corrected route searched in the past. Usually, a route from the departure point to the destination point is searched, but a portion from the current point that has reached the present point by moving on the route from the departure point corresponds to the existing route. Note that a search for a corrected route may be performed at the departure point, and in this case, the current point and the departure point coincide.

  The designated section setting means may set a designated section that has advanced from the current point to the destination point on the existing route by the designated distance, and the designated distance may be designated directly or indirectly by the user. For example, a designated point designated by the user on the existing route may be acquired, and the distance on the existing route from the current point to the designated point may be indirectly acquired as the designated distance. In this case, the end point of the designated section becomes the designated point.

  The first detour section setting means may set a first detour section starting from the starting point intersection on the existing route, and the first detour section may be a predetermined distance section or include a predetermined number of intersections. It may be a section. In the map information, the road is defined by the link connecting the node corresponding to the intersection. Of the links corresponding to the existing route, the link connecting to the node corresponding to the starting intersection (link corresponding to the next planned road to be driven). Is the first link corresponding to the first detour section. The end point of the next scheduled road may exist in the first detour section, or the next planned road may include the entire first detour section. Even when the end point of the next scheduled driving road exists in the first detour section, that is, even when the next scheduled driving road is shorter than the first detour section, the first correction ratio larger than the second correction ratio is set for the first detour section. Therefore, it is possible to secure a large route search cost for the next scheduled road to be overlapped with the first detour section.

  The first correction factor setting unit and the second correction factor setting unit increase the route search cost and satisfy the relationship of (first correction factor)> (second correction factor) and second correction factor. What is necessary is just to set a correction factor to a 1st bypass area and a 2nd bypass area, respectively. To increase the route search cost, the route search cost after the correction according to the first correction factor and the second correction factor is higher than that before the correction according to the first correction factor and the second correction factor. It means to become. That is, it means that the first correction factor and the second correction factor are greater than one. The first correction factor setting means may specify the whole or part of the link on the map information corresponding to the first bypass section, and set the first correction factor for the whole or part of the link. Similarly, the second correction factor setting means may set the second correction factor for all or part of the link corresponding to the second bypass section. The route search cost for the link can be obtained by multiplying the length of the road by an adjustment rate according to the road width, the number of lanes, the degree of traffic congestion, the average moving speed, etc. corresponding to the link. The rate setting unit and the second correction rate setting unit set a first correction rate and a second correction rate for further correcting the route search cost multiplied by the adjustment rate.

  Here, it is desirable to set the first correction factor as large as possible in order to reduce the possibility of searching for a corrected route having the next scheduled road as a constituent section. However, the first correction factor should be set to such an extent that the adverse effect of the total route search cost becoming too large does not occur. For example, the first correction factor may be set large in a range in which the total route search cost does not cause a carry to exceed a predetermined limit number of digits. The limit digit number is defined for the upper limit value of the number of digits that can be processed by the arithmetic unit that calculates the sum of route search costs, the upper limit value of the number of digits that can be recorded by the register for recording the sum, and the sum in the program. It can be determined by the number of digits of the data type. Basically, the total route search cost increases as the current point and the destination point are farther away, so the first correction factor may be corrected downward as the current point and the destination point are farther away. On the other hand, the second correction factor only needs to be smaller than the first correction factor and larger than 1, and may be a value obtained by multiplying the first correction factor by a predetermined coefficient less than 1, for example. In addition, since the possibility that the next scheduled road will be detoured increases as the first correction factor increases, the degree of desirability of the next scheduled road is accepted from the user, and the first correction factor is set according to the desired degree of detour. May be.

  The route search means corrects the route search cost for the links corresponding to the first bypass section and the second bypass section based on the first correction rate and the second correction rate, respectively. Here, the link corresponding to each of the first bypass section and the second bypass section includes a link corresponding to a road that entirely overlaps each of the first bypass section and the second bypass section. In addition, the links corresponding to the first bypass section and the second bypass section may include links corresponding to roads that only partially overlap the first bypass section and the second bypass section. . In this case, the route search cost of the link corresponding to the road is corrected based on the first correction rate adjusted according to the occupation ratio of the length of the portion overlapping the first detour section with respect to the length of the entire road. May be. Similarly, the route search cost of the link corresponding to the road is corrected based on the second correction rate adjusted according to the occupation ratio of the length of the portion overlapping the second detour section with respect to the length of the entire road. May be. The route search means only needs to search for a link group that minimizes the sum of the corrected route search costs, and various route search methods using the route search costs can be employed. For example, a Dijkstra method, an A * algorithm, or an improved algorithm thereof may be employed as a route search method.

  Here, the designated section setting means may set a designated section including the starting point intersection. That is, the designated section setting means may designate a designated distance longer than the distance from the current point to the starting point intersection on the existing route. If the specified distance is longer than the distance from the current point to the starting point intersection on the existing route, the specified section includes a section closer to the destination point than the starting point intersection. That is, it is possible to prevent the second correction factor from being set for a designated section (second detour section) that exists only in a section that cannot be detoured until the starting point intersection is reached from the current point. Therefore, it is possible to prevent the route search cost from being increased unnecessarily by setting the second correction factor for the second bypass section that exists only in the section that cannot be bypassed.

  In this case, the first detour section setting means determines the first detour section of the first detour section that is closer to the current point among the point that has traveled a certain distance from the starting point intersection to the destination point on the existing route and the end point of the specified section. It may be set as the end point. As a result, if the end point of the specified section is closer to the current point than the point that has traveled a certain distance from the starting point intersection to the destination point side, the end point of the first detour section in which the first correction factor is set is specified. Can be matched with the end point of. On the existing route, the section closer to the destination point than the end point of the designated section has a range where the user does not want to detour, and the first correction factor can be prevented from being applied to a section where the user does not want to detour. . That is, it is possible to prevent a route search that makes a detour to a section (range beyond the specified distance) that the user does not want to detour on the existing route. In this case, the length of the first detour section is shorter than a certain distance, but the first correction rate for the first detour section is set to be larger than the second correction rate to correct for the next scheduled road. Subsequent route search costs can be secured sufficiently high.

  The second correction factor setting means may set the second correction factor larger as the distance from the current point on the existing route becomes shorter. Thereby, the possibility that the section closer to the current point in the second detour section is adopted as the constituent section of the existing route can be reduced. Since the section on the existing route closer to the current location is more likely to be detoured, it is possible to strongly impress the user that the existing route has been corrected. In this case, the second correction factor is reduced as the second detour interval is farther from the current location, but even if the interval where the second correction factor is reduced includes the start intersection on the existing route, Since the first correction factor larger than the second correction factor is set for the first detour section starting from, it is possible to reduce the possibility of searching for a corrected route having the next scheduled road to be constructed as a constituent segment. .

  Further, the first detour section setting means may set, as a starting point intersection, an intersection that first arrives from the current point among intersections on an existing route to which a plurality of exit links that can exit after passing are connected. That is, it is desirable that the first detour section starts from an intersection where two or more options (one of which is a road on an existing route) exist on the exit link that can exit after passing. Even if the first correction factor is set for the first detour section starting from the intersection where there is no exit link option other than the section on the existing route, and the first detour section starting from the intersection, This is because the route that bypasses the first bypass section cannot be searched. That is, by not setting the first correction factor in the first bypass section that cannot be bypassed, it is possible to prevent the route search cost from being increased unnecessarily. Of course, the processing load may be reduced by omitting the determination of whether or not an exit link that can exit after passing is an intersection connecting one or more roads other than roads on the existing route.

  Further, a straight ahead priority section starting from the current point may be set. In the straight ahead priority section, the straight ahead priority means determines the non-straight forward correction rate that is the correction rate for the exit link that exits in the non-straight direction after passing the intersection, and the exit link that exits in the straight direction after passing the intersection. The correction rate is set to be larger than the straight-ahead correction rate and smaller than the first correction rate. By using the route search cost corrected in accordance with the correction rate set in this way, the route search means searches for a corrected route, so that a straight route is prioritized and a corrected route can be searched in a straight ahead priority section. That is, it is possible to prevent the user from being guided through a correction route that requires a sudden right or left turn. Note that exiting in the straight direction after passing through the intersection may mean that the angle difference between the approach direction and the exit direction with respect to the intersection is smaller than a predetermined angle. In this case, exiting in a non-straight direction after passing through the intersection means that the angle difference between the approach direction and the exit direction with respect to the intersection is equal to or greater than a predetermined angle.

  Here, there may be a case where a starting point intersection exists in the straight ahead priority section. In this case, the first correction factor setting means prioritizes the non-straight-line correction factor for the portion of the exit link that exits in the non-straight direction after passing from the intersection on the straight-ahead priority segment and that overlaps the first detour segment. 1 Set the correction factor. Similarly, the first correction rate is set in preference to the straight-line correction rate for the portion of the exit link that exits in the straight-ahead direction after passing from the intersection on the straight-ahead priority zone and overlaps with the first detour zone. That is, for the first detour section, the first correction factor is set regardless of the exit direction after passing through the starting point intersection. Since this first correction factor is larger than the non-straight-ahead correction factor, even if the next driving planned road scheduled to travel next to the starting point intersection in the existing route is in the straight traveling direction, the next driving planned road is set as the constituent section. The possibility that a correction route is searched can be reduced. It should be noted that the non-straight-ahead correction rate only needs to be relatively large with respect to the straight-ahead correction rate, and does not necessarily have to be a value (> 1) that increases the route search cost.

  Note that, as in the present invention, the method of searching for a route by setting the first correction factor and the second correction factor in the first bypass zone and the second bypass zone can be applied as a method or program for performing this process. It is. In addition, the route search system, method, and program to which the method of the present invention is applied may be realized as a single device or may be realized as a plurality of devices. For example, each means constituting the route search system may be provided in a plurality of substantial devices. Of course, a communication means for linking each means provided in a plurality of substantial devices may be provided. Further, some changes may be made as appropriate, such as a part of software and a part of hardware. Furthermore, the present invention is also realized as a recording medium for a program for controlling the route search system. Of course, the software recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium to be developed in the future.

It is a block diagram which shows a navigation apparatus. (2A) and (2B) are diagrams showing existing routes, and (2C) and (2D) are graphs of correction factors. It is a flowchart of a correction route search process. It is a flowchart of a correction rate table creation process. It is explanatory drawing of a straight ahead priority area.

Here, embodiments of the present invention will be described in the following order.
(1) Configuration of route search system:
(2) Correction route search processing:
(3) Other embodiments:

(1) Configuration of route search system:
FIG. 1 is a block diagram showing a configuration of a navigation device 10 as a route search system. The navigation device 10 is mounted on the vehicle C. The vehicle C includes a GPS receiving unit 41, a vehicle speed sensor 42, a gyro sensor 43, and a user I / F unit 44. An interface (not shown) is provided for the GPS receiver 41, the vehicle speed sensor 42, the gyro sensor 43, and the user I / F unit 44 to input and output various signals to and from the navigation device 10. The GPS receiver 41 receives radio waves from GPS satellites and outputs a signal for calculating the current location of the vehicle C to the navigation device 10. The vehicle speed sensor 42 outputs a signal corresponding to the rotational speed of the wheels included in the vehicle C to the navigation device 10. The gyro sensor 43 outputs a signal corresponding to the direction of the vehicle C to the navigation device 10. The user I / F unit 44 includes an output device (display, speaker, etc.) that outputs an image and sound for route guidance based on a control signal output from the navigation device 10. Further, the user I / F unit 44 includes an input device (touch sensor, button, etc.) for receiving a user operation, and outputs an operation signal corresponding to the operation received by the input device to the navigation device 10.

  The navigation device 10 includes a control unit 11 including a CPU, a RAM, a ROM, and the like, and a recording medium 12. The control unit 11 executes a navigation program 100 as a route search program recorded in the recording medium 12 or the ROM. The recording medium 12 records map information 12a, route information 12b, and a correction rate table 12c. The map information 12a includes node data indicating the positions of nodes set corresponding to intersections on the road on which the vehicle C travels, link data indicating links corresponding to roads connecting the intersections, and link shapes Including shape interpolation point data for specifying the. The link data indicates the length of the link. The route information 12b is data for specifying a configuration link of a route for reaching from the departure point to the destination point. The correction rate table 12c is data defining a correction rate for correcting the route search cost of each link in the route search process described later.

The navigation program 100 includes a navigation unit 110, an existing route information acquisition unit 120, a specified section setting unit 130, a first detour section setting unit 140, a first correction factor setting unit 150, a second correction factor setting unit 160, and a route searching unit 170. Including.
The navigation unit 110 is a module that causes the control unit 11 to perform a function of guiding the route to the user by the user I / F unit 44. The control unit 11 specifies a route based on the route information 12b, and guides the corrected route if the route information 12b is corrected. Further, the function of the navigation unit 110 causes the control unit 11 to detect the current position where the vehicle C is currently located based on the output signals from the GPS receiving unit 41, the vehicle speed sensor 42, the gyro sensor 43, the map information 12a, and the like. The point and the section where the vehicle C is traveling are specified.

  The existing route information acquisition unit 120 is a module that causes the control unit 11 to execute a function of acquiring existing route information indicating an existing route that is a route from the current point to the destination point. That is, by the function of the existing route information acquisition unit 120, the control unit 11 acquires route information 12b indicating a route from the departure point to the destination point, and a portion from the current point to the destination point among the routes indicated by the route information 12b. The existing route information indicating is acquired.

  The designated section setting unit 130 is a module that causes the control unit 11 to execute a function of setting, as a designated section, a section from the current point to a point that has advanced to the destination point side by a designated distance designated by the user on the existing route. With the function of the designated section setting unit 130, the control unit 11 refers to the map information 12 a and the route information 12 b, and starts from the current point among the intersections on the existing route to which a plurality of exit roads that can exit after passing are connected. Specify the intersection to be reached (hereinafter referred to as the starting intersection). The control unit 11 represents a node that connects a plurality of exit links that can be withdrawn, and represents an intersection corresponding to a node that is connected as an entrance link into which a link corresponding to a road including the current point can enter as a start point intersection. That is, an intersection where an approach road that enters from the current point, an exit road on an existing route that can exit after passing, and one or more exit roads that are not on an existing route that can exit after passage can be the starting point intersection. Note that the exit road that can exit after passing includes an exit road that makes a U-turn at the intersection and exits in the opposite direction to the approach road. Therefore, an intersection or the like that can only turn right and make a U turn can also be a starting point intersection. On the other hand, in addition to an approach road that enters from the current point and an exit road on an existing route that can exit after passing, an intersection that only other approach roads connect to cannot be a starting point intersection. For example, at a merge point where a merge lane from an interchange or the like merges with a highway main line, the only road that can be exited after passing is the highway main line, so the merge point cannot be a starting point intersection.

  Further, the control unit 11 sets a designated section including the starting point intersection by the function of the designated section setting unit 130. That is, the control unit 11 sets the distance from the current point on the existing route to the starting point intersection as the lower limit value of the specified distance. And the control part 11 receives designation | designated of the designated distance larger than a lower limit via the user I / F part 44 by the function of the designated area setting part 130. FIG. For example, the control unit 11 outputs a message such as “How much distance will be bypassed in the future” on the display or speaker included in the user I / F unit 44, and sets a plurality of specified distances larger than the lower limit value. Present it for selection. Then, the control unit 11 acquires the selected designated distance. For example, when there is a traffic jam section ahead of the existing route, the user designates the designated distance so that the traffic jam section is included in the designated section.

  When the designated distance is designated, the control unit 11 sets the section from the current point to the destination point that is advanced by the designated distance on the existing route as the designated section by the function of the designated section setting unit 130. As described above, since the lower limit value of the designated distance is the distance from the current point to the starting point intersection on the existing route, the designated point includes the starting point intersection. When the designated section is set by the function of the designated section setting unit 130, the control section 11 equally divides the designated section into N (N is an integer of 1 or more, N = 4 in this embodiment) so that the lengths are equal. By doing this, the division designation section is set.

2A and 2B are diagrams illustrating the existing route R. FIG. A link corresponding to a road on the existing route R is indicated by a bold arrow, a link corresponding to a road not on the existing route R is indicated by a dashed arrow, a node corresponding to an intersection connected to each road is indicated by a white circle, and the current location P is indicated by a double circle. The symbol in parentheses represents the distance. The direction of the arrow indicates the direction in which the vehicle C can travel. The distance between the end point T _D location points P and designated section D on existing route R is designated distance d _D. The designated distance d _D is larger than the distance between the current point P and the starting point intersection I on the existing route R, and the starting point intersection I is included in the designated section D. Further, division designation sections D1 to D4 are set by dividing the designation section D into N (= 4) equal parts. The lengths of the division designation sections D1 to D4 are 1 / N of the designated distance d _D. The start point and the end point of the current point P and the division designation sections D1 to D4 are not necessarily intersections. Therefore, the control unit 11 sets virtual nodes corresponding to the start and end points of the division designation sections D1 to D4 in the map information 12a, and sets a virtual link having at least one end of the virtual node.

The first detour section setting unit 140 has a function of setting, as a first detour section Q, a section on the existing route R starting from the starting point intersection I that first arrives from the current point P on the existing route R. A module to be executed. Specifically, the control unit 11 by the function of the first bypass section setting unit 140, and the point T _C advanced by a predetermined distance d _C the destination point G side from the starting point intersection I on existing route R, the end point of the specified section D among the T _D, it sets the closer to the current position P and the end point T _Q of the first bypass section Q in existing path R. Even if the endpoint T _Q of the first bypass section Q is not a crossing, in the map information 12a, the virtual node corresponding to the end point T _Q of the first bypass segment Q set virtual links that end point, the virtual link the Let it be the last link corresponding to one detour section Q. The constant distance d _C is a predetermined fixed distance, and is set to 500 [m] in the present embodiment.

In the example of FIG. 2A, the point T _C that has traveled from the starting point intersection I to the destination point G side by a certain distance d _C on the existing route R is more current on the existing route R than the end point T _D of the designated section D. Since it is close to the point P, the point T _C coincides with the end point T _Q of the first bypass section Q. In this case, the length of the first detour section Q is a constant distance d _C. In the example of FIG. 2A, the length of the next scheduled road M that is supposed to travel next to the starting point intersection I on the existing route R is shorter than a certain distance d _C , and the next intersection H is the first detour section. Exists in Q.

On the other hand, in the example of FIG. 2B, the end point T _D of the designated section D is on the existing route R rather than the point T _C that has traveled a certain distance d _C from the starting point intersection I to the destination point G side on the existing route R. close to the current position P in the end point T _D of the specified interval D coincides with the end point T _Q of the first bypass segment Q. In this case, the length of the first bypass section Q is shorter than the fixed distance d _C. In the example of Figure 2B, the starting point intersection next intersection H is far from the current point P than the end point T _Q of I, end point T _Q The following target road M corresponding to a single link of the first bypass section Q Exists within. In this case, a virtual link corresponding to the entire first detour section Q is included in the link corresponding to the next scheduled road M.

  The first correction factor setting unit 150 is a module that causes the control unit 11 to execute a function of setting a correction factor for correcting the route search cost for the first bypass section Q to a first correction factor that increases the route search cost. . The route search cost is obtained by multiplying the length of the link by, for example, an adjustment rate according to the road width, the number of lanes, the degree of traffic congestion, the average moving speed, and the like corresponding to the link. That is, a route search cost proportional to the length is obtained for each of the links corresponding to the first bypass section Q, but the control unit 11 corrects the route search cost by multiplying the route search cost. The rate is set to the first correction rate. The control unit 11 sets the first correction rate for all or part of the links (virtual links) corresponding to the first detour interval Q by the function of the first correction rate setting unit 150.

2C and 2D are graphs showing correction rates set for all and some of the links (virtual links) corresponding to the existing route R shown in FIGS. 2A and 2B. 2C and 2D, the vertical axis represents the correction factor, and the horizontal axis represents the distance from the current point P on the existing route R. As shown in FIG. 2C, the first correction factor indicated by the solid line is set for all and a part (virtual link) of the links corresponding to the first detour section Q having a certain distance d _C. . As shown in FIG. 2D, the link corresponding to the next scheduled road M includes a virtual link (denoted as m in FIG. 2D) corresponding to the first detour section Q. A first correction factor is set for the portion corresponding to. In the present embodiment, the first correction factor is 160.

In the present embodiment, the first correction factor (160) is set large in a range in which the sum of route search costs in route search does not cause a carry to exceed a predetermined limit number of digits. The limited number of digits is the number of digits corresponding to the data type defined for the total route search cost in the navigation program 100. Here, since the maximum length of the first detour section Q is the fixed distance d _C , the value obtained by multiplying the fixed distance d _C by the first correction factor depends on the first correction factor and is the total route search cost. It can be considered that this corresponds to the maximum value that increases. Obtain the maximum sum of route search costs in a plurality of route searches conducted experimentally without setting the first correction factor, and the value of the sum of route search costs that cause the carry to exceed the limit digits margin width obtained by subtracting the maximum value from the found to be equal to a value obtained by multiplying the first correction factor to the fixed distance d _C, and a constant distance d _C a first correction factor has been set.

  The second correction factor setting unit 160 sets the correction factor for the second bypass segment W, which is a segment excluding the first bypass segment Q in the specified segment D, smaller than the first correction factor and increases the route search cost. This is a module that causes the control unit 11 to execute the function of setting the second correction factor to be performed. That is, by the function of the second correction rate setting unit 160, the control unit 11 sets the second correction rate as the correction rate of the route search cost for the second detour interval W that does not overlap with the first detour interval Q in the specified interval D. To do. In the present embodiment, the control unit 11 sets a different second correction factor for each section corresponding to the division designation sections D1 to D4 in the second bypass section W. Here, the second correction factor is set to be larger as the distance between the corresponding division designation sections D1 to D4 and the current point P on the existing route R is shorter. The second correction factor is smaller than the first correction factor and larger than one. As shown in FIGS. 2C and 2D, in the present embodiment, the second correction factor indicated by the alternate long and short dash line for each of the links (virtual links) corresponding to the division designation sections D1 to D4 in the second bypass section W is 35, respectively. 33, 31, 29 are set.

  The route search unit 170 corrects the route search costs for the links corresponding to the first detour interval Q and the second detour interval W based on the first correction rate and the second correction rate, respectively, and the route search cost. This is a module that causes the control unit 11 to execute a function of searching for a route corresponding to a link group that minimizes the sum of the two as a corrected route of the existing route. First, with the function of the route search unit 170, the control unit 11 calculates a correction rate for the entire link for a link for which a virtual link is set in the correction rate table 12c. The control unit 11 sets a virtual link corresponding to the remaining part of the link excluding the virtual link for which the first correction rate or the second correction rate is set, and the correction rate for the virtual link corresponding to the remaining part Is set to 1. For example, in the next scheduled road M of FIG. 2D, a virtual link is also set for a portion excluding the virtual link (shown as a solid line) for which the first correction factor (shown by a solid line) is set, and the correction for the virtual link is performed. The rate is set to 1 (illustrated with a two-dot chain line). Then, the control unit 11 calculates an occupation ratio obtained by dividing the length of the virtual link by the length of the entire link including the virtual link, and a correction ratio (first value) set for the virtual link in the occupation ratio. The contribution correction rate is calculated by multiplying the correction rate, the second correction rate, or 1). Furthermore, the control unit 11 records the sum of the contribution correction rates for each virtual link constituting a single link as the correction rate for the link in the correction rate table 12c. As a result, the correction rate is recorded for each link in the correction rate table 12c.

  With the function of the route search unit 170, the control unit 11 acquires a route search cost before correction for each link (for example, a link corresponding to a section within a predetermined search range from the existing route R). That is, the control unit 11 acquires a route search cost obtained by multiplying the link length by, for example, an adjustment rate according to the road width, the number of lanes, the degree of traffic congestion, the average moving speed, and the like corresponding to the link. The route search cost may be recorded in advance in the map information 12a, or may be calculated every time a route search is performed. With the function of the route search unit 170, the control unit 11 corrects the route search cost by multiplying the correction rate recorded for each link in the correction rate table 12c by the route search cost acquired for each link. As a result, the route search cost is corrected for the link in which the first correction factor and the second correction factor are set in the existing route R and the link including the virtual link in which the first correction factor and the second correction factor are set. The By the function of the route search unit 170, the control unit 11 minimizes the sum of the route search cost after correcting the link connecting from the current point P to the destination point G by the Dijkstra method, the A * algorithm, or an improved algorithm thereof. The route corresponding to the link group to be searched is searched as a corrected route of the existing route R.

In the above configuration, the second bypass section excluding the first bypass section Q from the specified section D from the current point P to the point that has traveled to the destination point G by the specified distance d _D specified by the user on the existing route R For the link corresponding to W, the route search cost is increased by the second correction factor. Further, the route search cost is increased by the first correction rate that is larger than the second correction rate in the specified zone D that overlaps the first bypass zone Q. Therefore, it is possible to reduce the possibility that the designated section D having the designated distance d _D designated by the user is adopted as the constituent section of the correction route. That is, it is possible to search for a corrected route that bypasses the existing route R for the range specified by the user.

Further, in the first detour section Q starting from the starting point intersection I on the existing route R, the starting point S _Q and the next scheduled road M scheduled to travel after passing the starting point intersection I on the existing route R are common. That is, the first detour section Q and the next scheduled road M have a relationship that at least partly overlaps. This relationship is maintained no matter how the designated distance d _D is designated. Therefore, by setting the first correction factor for the first detour section Q at least partially overlapping with the next scheduled road M by the function of the first correction factor setting unit 150, the next driving is performed regardless of the designated distance d _D. The route search cost for the link corresponding to the planned road M can be increased by the first correction factor. Therefore, it is possible to reduce the possibility that the link corresponding to the next scheduled road M will be adopted as the component link of the correction route. Note that, by setting a first correction factor that is larger than the second correction factor for the next scheduled road M that overlaps the first detour section Q, even if the next scheduled road M is short, the next scheduled road A route search cost for M can be largely secured. Accordingly, as shown in FIGS. 2A and 2C, even if the next scheduled road M is short, it is possible to reduce the possibility that the next scheduled road M is adopted as a component section of the corrected route. Further, the route search is not performed by setting the second correction rate smaller than the first correction rate for the second bypass interval W without setting the first correction factor for both the first bypass interval Q and the second bypass interval W. The adverse effect of the total cost becoming too large can be prevented.

  Since the possibility that the next scheduled road M will be adopted as a component section of the corrected route can be reduced, a corrected route that makes a U-turn from the intersection H at the end point of the next scheduled road M to the starting point intersection I is searched. Can also be prevented. For example, the sum of the route search costs for the route toward the destination point G via the opposite lane (section) of the lane (section) including the current point P becomes smaller than other corrected routes, and the starting point from the current point P It is assumed that a U-turn when entering the intersection I is prohibited and a U-turn at the intersection H at the end point of the next scheduled road M is not prohibited. In this case, if the first correction factor is not set for the first detour section Q (the next scheduled road M), the vehicle exits from the starting point intersection I to the scheduled section M as shown by a two-dot chain line in FIG. 2A. A route that makes a U-turn at the intersection H at the end point of the scheduled traveling section M and makes a left turn at the start point intersection I can be searched for as a corrected route. However, if the first correction factor is set for the next scheduled road M as in this embodiment, the possibility that the next scheduled road M will be adopted as a component section of the corrected route can be reduced. A route that makes a U-turn at the end point of the planned road M can be prevented from being searched for as a corrected route. Note that by setting a correction factor that increases the route search cost even in the section corresponding to the opposite lane of the first detour section Q, the route that makes a U-turn at the intersection H at the end point of the next scheduled road M is corrected. The possibility of searching by route may be further reduced.

The control unit 11 by the first detour interval setting unit 140, out of the point T _C advanced to the destination point G by a predetermined distance d _C from the start point intersection I on existing route R, and the end point T _D of the designated section D, The one closer to the current point P is set as the end point T _Q of the first bypass section Q. Therefore, as long as the end point T _D of the designated section D is not closer to the current point P than the point T _C that is advanced from the starting point intersection I to the destination point G by a certain distance d _C , as shown in FIG. The length of the detour section Q can be secured by a certain distance d _C. As a result, it is possible to secure a large corrected route search cost for the first bypass section Q having a certain distance d _C, and the link corresponding to the first bypass section Q can be adopted as the constituent section of the corrected route. Can be reduced.

On the other hand, when they are near the end point T constant from the start point intersection I towards _D to the destination point G the distance d _C only advanced point T _C current point P than the specified interval D, as shown in FIG. 2B, the first the end point T _Q of the first bypass segment Q correction ratio is set can be matched with the end point T _D of the specified interval D. On the existing route R, the section closer to the destination point G than the end point T _D of the designated section D has a range in which the user does not want to make a detour and extends to a section in which the user does not want to make a detour (more than the designated distance d _D ). Application of the first correction factor can be prevented. In other words, it is possible to prevent a route search that makes a detour to a range in a range where the user does not want to detour on the existing route R. In this case, by the length of the first bypass segment Q is shorter than the predetermined distance d _C, the length of the first bypass section Q as shown in FIG. 2B may be shorter than the next target road M, By making the first correction factor for the first detour section Q greater than the second correction factor, the corrected route search cost for the next scheduled road M can be secured sufficiently high.

Due to the function of the second correction factor setting unit 160, the control unit 11 sets the second correction factor larger as the distance from the current point P on the existing route R becomes shorter. Thereby, the possibility of being adopted as a constituent section of the existing route R can be reduced as the section corresponding to the division designation sections D1 to D4 close to the current point P in the second detour section W. In this case, the second correction factor is made smaller in the second detouring zone W that is farther from the current point P. However, as shown in FIG. 2B, the divided designated zone D4 in which the second correction factor is made smaller is the existing route R. Even if the upper starting point intersection I is included, a first correction factor larger than the second correction factor is set for the first detour section Q having the starting point intersection I as the starting point S _Q. It is possible to reduce the possibility of searching for a corrected route having the link corresponding to the planned road M as a constituent link.

In addition, the first detour section setting unit 140 causes the control unit 11 to start from the current point P among the intersections on the existing route R where one or more exit roads that can exit after passing are connected to other than the sections on the existing route R. the starting point intersection I is an intersection to reach the set start point S _Q of the first bypass segment. That is, by not setting the first correction factor for the first bypass section Q that cannot be detoured, it is possible to prevent the route search cost from being increased unnecessarily.

(2) Correction route search processing:
FIG. 3 is a flowchart of the correction route search process executed by the navigation device 10. In step S100, the control unit 11 acquires a predetermined constant distance d _C and a specified distance d _D specified by the user, and based on these, the specified section D, the first bypass section Q, and the second bypass section W are acquired. And set. Furthermore, in step S100, the control unit 11 equally divides the designated section D into N and sets divided designated sections D1 to D4.

  In step S200, the control unit 11 executes a correction rate table creation process. FIG. 4 is a flowchart of the correction rate table creation process. In step S205, the control unit 11 selects one of the links corresponding to the route from the departure point to the destination point G indicated by the route information 12b as a processing target link. In step S210, the control unit 11 determines that the processing target link is a link (including a link corresponding to a road including the current location P) corresponding to a road beyond the current location P from the departure location in the route indicated by the route information 12b. It is determined whether or not there is. If the link to be processed is not a link corresponding to a road beyond the current point P from the departure point, the process returns to step S205. That is, in steps S <b> 205 to S <b> 210, a loop process is performed in which only the links corresponding to the existing route R from the current point P to the destination point G are extracted.

  When it is determined in step S210 that the processing target link is a link corresponding to a road that is beyond the current point P from the departure point, the control unit 11 executes step S215. In step S215, the control unit 11 determines whether at least a part of the road corresponding to the processing target link overlaps at least one of the first bypass section Q and the second bypass section W. When at least a part of the road corresponding to the processing target link does not overlap with at least one of the first detour section Q and the second detour section W, the control unit 11 proceeds to step S260, and the route information 12b indicates It is determined whether all the links corresponding to the route have been processed. If not all the links corresponding to the route indicated by the route information 12b are to be processed, the process returns to step S205 to set the next link as a processing target. That is, when at least a part of the road corresponding to the processing target link does not overlap with the first detour section Q or the second detour section W, both the first correction factor and the second correction factor are set for the link. Assuming that there is no need to do this, the next link is the processing target.

  When it is determined in step S215 that at least a part of the road corresponding to the processing target link overlaps at least one of the first detour section Q and the second detour section W, the control unit 11 performs step S220. Execute. In step S220, the control unit 11 determines whether or not the entire road corresponding to the processing target link overlaps the first detour section Q. If the entire road corresponding to the processing target link overlaps the first detour section Q, the control unit 11 sets the first correction factor for the entire processing target link in step S225.

  On the other hand, when it is not determined in step S220 that the entire road corresponding to the processing target link overlaps the first detour section Q, the control unit 11 executes step S230. In step S230, the control unit 11 determines whether or not at least a part of the first detour section Q overlaps a part of the road corresponding to the processing target link. When at least a part of the first detour section Q overlaps a part of the road corresponding to the processing target link, the control unit 11 executes Step S235. In step S235, the control unit 11 sets a virtual link corresponding to a part where the first bypass section Q overlaps for the processing target link, and sets a first correction factor for the virtual link.

  When the first correction factor is set for the virtual link in step S235, the control unit 11 executes step S240. In step S240, the control unit 11 determines whether at least a part of the second detour section overlaps a part of the road corresponding to the processing target link. When at least a part of the second detour section overlaps a part of the road corresponding to the processing target link, the control unit 11 executes Step S245. In step S245, the control unit 11 sets a virtual link corresponding to a part overlapping with the second bypass section in the processing target link, and sets a second correction factor for the virtual link. When both steps S230 and S240 are affirmed, a portion corresponding to the link to be processed coexists with a portion overlapping the first detour interval Q and a portion overlapping the second detour interval W. A first correction factor (S235) and a second correction factor (S245) are set for the virtual link corresponding to. On the other hand, when only step S230 is affirmed, there is only a portion overlapping with the first detour section Q on the road corresponding to the link to be processed, so the first correction factor ( S235) is set.

  In step S245, the control unit 11 sets a second correction rate according to the division designation sections D1 to D4. In addition, when the part of the road corresponding to the virtual link for which the second correction factor is set overlaps with a plurality of division designation sections D1 to D4, a virtual link obtained by further dividing the virtual link for each division designation section D1 to D4 is set. Then, the second correction factor corresponding to the division designation sections D1 to D4 is set for each virtual link. Hereinafter, when the second correction factor is set, the same processing is performed.

  If it is not determined in step S230 that at least a part of the first detour section Q overlaps a part of the road corresponding to the processing target link, the control unit 11 executes step S250. In step S250, the control unit 11 determines whether or not the entire road corresponding to the processing target link overlaps the second detour section W. When the entire road corresponding to the processing target link overlaps with the second detour section W, the control unit 11 executes Step S255. In step S255, the control unit 11 sets the second correction factor for the entire processing target link.

  When it is not determined in step S250 that the entire road corresponding to the processing target link overlaps the second detour section W, the control unit 11 executes step S245. If it is not determined in step S250 that the entire road corresponding to the processing target link overlaps with the second bypass section W, a part of the road corresponding to the processing target link overlaps only with the second bypass section W. It becomes. Accordingly, in step S245, the control unit 11 sets a virtual link corresponding to a part of the road corresponding to the processing target link that overlaps the second bypass section W, and sets the second correction factor for the virtual link. Set.

  When the processing for setting the first correction rate and the second correction rate (steps S225, S235, S245, and S255) is executed as described above, the control unit 11 proceeds to step S260 and corresponds to the route indicated by the route information 12b. It is determined whether all of the links have been processed. If not all the links corresponding to the route indicated by the route information 12b are to be processed, the control unit 11 returns to step S205 and sets the next link as a processing target. By executing the above loop processing, the first correction factor and the second correction factor can be set for the link corresponding to the existing route R.

  If it is determined in step S260 that all of the links corresponding to the route indicated by the route information 12b are to be processed, the control unit 11 creates the correction rate table 12c in step S265. That is, for a link for which a virtual link is set, a correction rate for the entire link is calculated, and a correction rate table 12c in which the correction rate for the entire link is recorded for each link is created. As described above, the correction rate of the entire link is calculated by summing up the contribution correction rates according to the occupation ratio of the virtual link.

  When the correction rate table 12c can be created as described above, the control unit 11 performs a route search in step S300 of FIG. That is, the control unit 11 corrects the route search cost by calculating the route search cost before correction for each link and multiplying the correction rate recorded for each link in the correction rate table 12c. Further, the control unit 11 searches for the corrected route of the existing route R so that the total route search cost after correction of the link connecting from the current point P to the destination point G becomes small. In step S <b> 400, the control unit 11 records the searched correction route in the route information 12 b and causes the user I / F unit 44 to output an image and sound for guiding the correction route.

(3) Other embodiments:
By the way, in order to prevent the vehicle from being guided to turn right or left immediately after the start of the route guidance, the correction route may be searched so as to go straight in the straight ahead priority section starting from the current point P. In the straight ahead priority section, the control unit 11 exits the non-straight forward correction rate, which is a correction rate for the exit link corresponding to the exit road that exits in the non-straight direction after passing the intersection, in the straight direction after passing the intersection. It is set to be larger than the straight-ahead correction rate, which is the correction rate for the exit link corresponding to the exiting road, and smaller than the first correction rate. In the present embodiment, the control unit 11 sets the non-straight forward correction factor for the exit link corresponding to the exit road that exits the intersection in the straight ahead priority section in the non-straight direction and sets the exit road to exit the intersection in the straight direction. The straight-line correction rate for the corresponding exit link is set to 0.8. The control unit 11 records the correction rate in the correction rate table 12c. In the present embodiment, a leaving road whose leaving direction is greater than 30 degrees with respect to the entering direction is defined as a leaving road that leaves in a non-straight direction. On the other hand, an exit road whose exit direction is 30 degrees or less with respect to the approach direction is defined as an exit road that exits in the straight direction. By using the route search cost corrected in accordance with the correction rate set as described above, the control unit 11 searches for a correction route so that straight travel is prioritized in the straight travel priority section. it can. That is, it is possible to prevent the user from being guided through a correction route that requires a sudden right or left turn.

FIG. 5 is a diagram illustrating the straight ahead priority section F. The lines and symbols in FIG. 5 indicate the same objects as in FIGS. 2A and 2B. In the example of the figure, a straight travel priority section F is set by a predetermined distance in the straight travel direction from the current point P, and the starting point intersection I exists in the straight travel priority section F. Further, an existing route R indicated by a bold line is set, and a leaving road that exits in a straight line direction after passing through the starting point intersection I is set as a next scheduled road M on the existing route R. In such a case, the control unit 11 by the first detour interval setting unit 140 sets a first bypass section Q to the starting point intersection I present in the straight priority section F starting S _Q. Further, by the function of the first correction factor setting unit 150, the control unit 11 is configured to use the exit links corresponding to exit roads that exit from the intersections I and H on the straight ahead priority section F and exit in the non-straight direction (right-left turn direction). For the portion overlapping the first detour section Q, the first correction factor is set in preference to the non-straight-ahead correction factor. Similarly, by the function of the first correction rate setting unit 150, the control unit 11 causes the first detour section Q of the exit links corresponding to the exit roads that exit from the intersections I and H on the straight travel priority section F to travel straight ahead. The first correction factor is set to give priority to the straight-ahead correction factor for the overlapping part. That is, for the first detour section Q, the first correction factor is set regardless of the exit direction after passing the starting point intersection. In the example of FIG. 5, priority is given to the straight-line correction rate for the entire portion between the next scheduled roads M and the exit link corresponding to the exit road K exiting from the intersection H in the straight-ahead direction with a dotted circle. To set the first correction factor. This first correction factor is larger than the non-straight-ahead correction factor set for the exit link corresponding to the exit road (one-dot chain line) exiting from the starting point intersection I in FIG. Even in the case where the next scheduled road M scheduled to travel next to the starting point intersection I is in a straight ahead direction, the possibility of searching for a corrected route having the next planned scheduled road M as a constituent section can be reduced. When it is set to straight priority section F, the end point of the section and rectilinear preferential section F with the existing path R overlaps may be the starting point S _D for the specified interval D.

With the function of the existing route information acquisition unit 120, the control unit 11 may acquire existing route information indicating the existing route R from the current point P to the destination point G, and the existing route R is a corrected route searched in the past. There may be. The function of the designated section setting unit 130 allows the control unit 11 to set the designated section D that has traveled from the current point P to the destination point G by the designated distance d _D on the existing route R. The designated distance d _D is determined by the user. It may be specified indirectly. For example, a designated point designated by the user on the existing route R may be acquired, and a distance on the existing route R from the current point P to the designated point may be set as the designated distance d _D. In this case, the end point T _D of the specified interval D becomes the specified point. In the above embodiment has been limited to specified distance d _D than the distance to the current position P and the starting point intersection I is large, the designated distance d _D is even less distance to the current position P and the starting point intersection I Good. Even in this case, since the first correction factor is set for the first detour section Q starting from the starting point intersection I, it is possible to prevent the link corresponding to the next scheduled road M from being adopted as the constituent link of the corrected route. . In addition, the navigation device 10 may not include a user interface that accepts designation of a designated distance from the user. For example, the designated distance designated in another device may be acquired by communication or the like.

  The function of the first detour section setting unit 140 allows the control unit 11 to set a first detour section Q starting from the starting point intersection I on the existing route R. The first detour section Q is predetermined on the existing route R. It may be a section including a number of intersections. In the above-described embodiment, the first correction factor is set large in a range in which the sum of the route search costs does not cause a carry to exceed the limit digits determined by the number of digits of the data type on the program. The limit number of digits may be determined by, for example, an upper limit value of the number of digits that can be processed by the arithmetic unit that calculates the total route search cost, or an upper limit value of the number of digits that can be recorded by the register that records the sum. Basically, the total sum of the route search costs increases as the current point P and the destination point G are farther away. Therefore, the first correction factor may be corrected downward as the current point P and the destination point G become farther away. Good. On the other hand, the second correction factor only needs to be smaller than the first correction factor and larger than 1, and may be a value obtained by multiplying the first correction factor by a predetermined coefficient less than 1, for example. Further, since the possibility that the next scheduled road M will be detoured increases as the first correction ratio increases, the degree of detouring of the next scheduled road M is accepted from the user, and the first correction ratio is determined according to the degree of detouring desired. May be set.

DESCRIPTION OF SYMBOLS 10 ... Navigation apparatus, 11 ... Control part, 12 ... Recording medium, 12a ... Map information, 12b ... Route information, 12c ... Correction rate table, 12 ... Recording medium, 41 ... GPS receiving part, 42 ... Vehicle speed sensor, 43 ... Gyro Sensors 44... User I / F section 100 100 Navigation program 110 Navigation section 120 Existing route information acquisition section 130 Designated section setting section 140 First detour section setting section 150 First correction factor Setting unit, 160 ... second correction factor setting unit, 170 ... route search unit, C ... vehicle, D ... designated section, d _C ... fixed distance, d _D ... designated distance, F ... straight ahead priority section, G ... destination point, I: Start intersection, M: Next planned road, P: Current location, Q: First detour section, W: Second detour section, R: Existing route.

Claims (7)

Existing route information acquisition means for acquiring existing route information indicating an existing route that is a route from the current point to the destination point;
A designated section setting means for setting a section from the current point to a point that has traveled to the destination point side by a designated distance designated by the user on the existing route;
A first detour section setting means for setting a section on the existing route as a first detour section starting from a starting point intersection that is an intersection that first arrives from the current point on the existing route;
First correction factor setting means for setting a correction factor for correcting the route search cost for the first detour section to a first correction factor for increasing the route search cost;
The correction rate for correcting the route search cost for the second bypass interval, which is the interval excluding the first bypass interval in the designated interval, is smaller than the first correction rate and increases the route search cost. A second correction factor setting means for setting the second correction factor;
Correcting the route search costs for the links corresponding to the first detour section and the second detour section based on the first correction rate and the second correction rate, respectively, and summing up the route search costs Route search means for searching for a route corresponding to a link group that minimizes as a correction route of the existing route;
A route search system comprising: The designated section setting means sets the designated section including the starting point intersection,
The first detour section setting means is close to the current position on the existing route among a point that has traveled a certain distance from the starting point intersection to the destination point on the existing route and an end point of the designated section Is set as the end point of the first detour section,
The route search system according to claim 1. The second correction factor setting means sets the second correction factor larger as the distance from the current point on the existing route becomes shorter;
The route search system according to claim 1 or 2. The first detour section setting means sets, as the starting point intersection, an intersection that first arrives from the current point among intersections on the existing route to which a plurality of exit links that can exit after passing are connected.
The route search system according to any one of claims 1 to 3. In the straight ahead priority section starting from the current point, a non-straight forward correction factor that is a correction factor for correcting the route search cost for the exit link that exits in the non-straight forward direction after passing through the intersection is obtained after passing through the intersection. Straight running priority means that is set to be larger than a straight-line correction rate that is a correction rate for correcting the route search cost for a leaving link that leaves in a straight-ahead direction and smaller than the first correction rate;
The first correction factor setting means prioritizes the non-straight-line correction factor for a portion of the exit link that exits in a non-straight direction after passing from an intersection on the straight-ahead priority segment, overlapping the first detour segment. A first correction factor is set, and a portion of the exit link that exits in the straight traveling direction after passing from the intersection on the straight traveling priority section overlaps with the first detour section has priority over the straight traveling correction ratio. Set the rate,
The route search system according to any one of claims 1 to 4. An existing route information acquisition step of acquiring existing route information indicating an existing route that is a route from the current point to the destination point;
A designated section setting step for setting a section from the current point to a point that has advanced to the destination point side by a designated distance designated by the user on the existing route;
A first detour section setting step of setting a section on the existing route as a first detour section starting from a starting point intersection that is an intersection that first arrives from the current point on the existing path;
A first correction factor setting step of setting a correction factor for correcting the route search cost for the first detour section to a first correction factor for increasing the route search cost;
The correction rate for correcting the route search cost for the second bypass interval, which is the interval excluding the first bypass interval in the designated interval, is smaller than the first correction rate and increases the route search cost. A second correction factor setting step for setting the second correction factor;
Correcting the route search costs for the links corresponding to the first detour section and the second detour section based on the first correction rate and the second correction rate, respectively, and summing up the route search costs A route search step of searching for a route corresponding to a link group that minimizes the route as a correction route of the existing route;
Route search method including An existing route information acquisition function for acquiring existing route information indicating an existing route that is a route from the current point to the destination point;
A designated section setting function for setting a section from the current point to a point that has advanced to the destination point side by a designated distance designated by the user on the existing route;
A first detour section setting function for setting a section on the existing route as a first detour section starting from a starting point intersection that is an intersection that first arrives from the current point on the existing route;
A first correction factor setting function for setting a correction factor for correcting the route search cost for the first detour section to a first correction factor for increasing the route search cost;
The correction rate for correcting the route search cost for the second bypass interval, which is the interval excluding the first bypass interval in the designated interval, is smaller than the first correction rate and increases the route search cost. A second correction factor setting function for setting the second correction factor;
Correcting the route search costs for the links corresponding to the first detour section and the second detour section based on the first correction rate and the second correction rate, respectively, and summing up the route search costs A route search function for searching for a route corresponding to a group of links that minimizes as a corrected route of the existing route;
A route search program that causes a computer to execute.

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