JP4168987B2 - Navigation device and program - Google Patents

Description

  The present invention relates to a technique for calculating an appropriate route while incorporating user preferences in route calculation processing.

  There are known navigation devices that display the current position of the vehicle as it travels along with the road map on the monitor, set an appropriate route from the current location to the destination, and provide route guidance. It contributes to the drive. In the route calculation process described above, a route from the departure point to the destination is calculated with reference to the map data and a preset link cost table.

In addition, in such a navigation device, in order to avoid the suitability of the calculated route in the route calculation process, a specific route is calculated with reference to the link cost table selected by the user. In some cases, an alternative route is calculated with reference to a link cost table other than the specific link cost table, and weights are given to the links that overlap between the specific route and the alternative route (see, for example, Patent Document 1).
JP 2003-130669 A (7th and 8th pages, FIG. 21)

  However, in the navigation apparatus as described above, there is a possibility that the calculated route is not a preferred route for the user to avoid making a detour for the following reasons. That is, in the navigation apparatus as described above, it is expected that the specific route and the alternative route overlap with each other on various types of roads such as highways and general roads. In such a case, for users who prefer specific types of roads such as expressways and toll roads, weighting for overlapping links is performed on various types of roads. Roads are not always weighted with priority, and a route that does not include many specific types of roads preferred by the user may be calculated.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a technique for calculating an appropriate route while incorporating a user's preference in route calculation processing.

  The route calculation apparatus according to claim 1, which has been made to solve the above problem, is characterized in that “in the route calculation process, the specific route is recalculated to reflect the tendency of the alternative route”.

  Specifically, the map data acquisition means (6: In this column, in order to facilitate understanding of the invention, the symbols used in the “Best Mode for Carrying Out the Invention” column are attached as necessary. This code does not mean that the scope of claims is limited.) However, map data including information on roads can be acquired, and the link cost table storage means stores a plurality of link cost tables. The link cost table is a list of additional magnifications for weighting the link cost set for each link. For each link cost table, for example, priority is given to travel distance or a fee is charged. Each may have a different tendency, such as giving priority to roads. Further, the route calculation means stores the specific route from the departure place set by the departure place setting means to the destination set by the destination setting means, the map data acquired by the map data acquisition means, and the link cost table storage means Is calculated with reference to a specific link cost table which is one of the link cost tables stored in the table. Further, the alternative route calculation means calculates the alternative route from the departure point to the destination with reference to the map data and another link cost table having a tendency different from the specific link cost table.

  Further, the suitability determination means determines whether or not the above-mentioned specific route is appropriate based on the ratio of the cost value of the specific route to the cost value of the alternative route. For example, if the ratio of the cost value of the specific route to the cost value of the alternative route is greater than or equal to the specified value, it is determined that the specific route is not appropriate, while the cost of the specific route with respect to the cost value of the alternative route. For example, when the ratio of the values is less than the specified value, it is determined that the specific route is appropriate. When the specific route is determined to be appropriate by the suitability determining unit, the route calculation result determining unit sets the specific route as the route calculation result. Further, the route guidance means guides the route calculation result determined by the route calculation result determination means.

  On the other hand, if it is determined by the suitability determining means that the specific route is not appropriate, the route recalculating means executes the following route recalculating process. That is, (a) the route recalculation means corrects the additional magnification corresponding to the road type that does not overlap with the road type included in the specific route among the road types included in the alternative route in the specific link cost table to a smaller value. Then, the specific route is recalculated with reference to the corrected specific link cost table by the route calculation means. (B) Alternatively, the route recalculation means increases the additional magnification corresponding to the road type that does not overlap with the road type included in the alternative route among the road types included in the specific route in the other link cost table described above. The value is corrected to the value, and the alternative route is calculated again by referring to another link cost table after the correction by the alternative route calculation means.

  In addition, when the route recalculation is performed by the route recalculation unit as described above, the suitability determination unit determines again whether or not the above-described specific route is appropriate. If the route recalculation means recalculates the route and the suitability determination means determines that the specific route is appropriate, the route calculation result determination means sets the specific route as the route calculation result. If the specific route is determined not to be appropriate by the suitability determination unit, the route recalculation unit executes the route recalculation process again.

  In conventional navigation devices, weighting for links that overlap between a specific route and an alternative route is performed on various types of roads, so weighting is not necessarily focused on specific types of roads. In some cases, a route that does not include a particular type of road that the user likes is calculated, and the calculated route may not be a route that the user prefers to avoid making a detour. On the other hand, according to the present invention, the specific route is recalculated in the route calculation process to reflect the tendency of the alternative route, so that the characteristics of the specific link cost table used when calculating the specific route are utilized. The route can be corrected to the route incorporating the characteristics of other link cost tables used in calculating the alternative route, and the appropriate route can be calculated while incorporating the user's preference.

  In addition, about the above-mentioned departure place, setting according to the input from a user can be considered, for example. It is also conceivable to set the current position as the departure place. Specifically, it is conceivable that the departure place setting means sets the current position specified by the position specifying means as the departure place.

  In addition, the above-mentioned specific link cost table is preferably a link cost table reflecting user preferences, and as a specific example thereof, a link cost table set so that all of a plurality of routes assumed in advance are appropriate. Also, a link cost table that tends to shorten the total extended distance of the route, a link cost table that tends to shorten the time required to move the route, and the like can be considered. The same applies to the link cost table having a tendency different from that of the specific link cost table.

  In addition, the above-described suitability determination means may be configured as follows. That is, (c) when an alternative route is calculated using a link cost table that tends to shorten the total extended distance of the route, the suitability determining means determines whether or not the specific route is a detour. (D) If an alternative route is calculated using a link cost table that tends to shorten the time required to move the route, whether or not the suitability determination means takes time to move the specific route. Determine whether.

  By the way, there may be a plurality of road types that do not overlap with the types of roads included in the alternative route among the types of roads included in the optimum route described above. Therefore, as in claim 2, when there are a plurality of additional magnification candidates to be corrected when the specific route is recalculated by the route calculating unit or the alternative route is recalculated by the alternative route calculating unit, It is conceivable that the recalculation means preferentially corrects the additional magnification having a long road length of the road type corresponding to the additional magnification in either the specific route or the alternative route (claim 2). In this way, since the effect of recalculation is increased, it is possible to calculate an appropriate route while incorporating user preferences with a smaller number of recalculations.

  Even if the route calculation means recalculates the specific route many times, the suitability determination means may determine that the specific route is not appropriate. Therefore, as described in claim 3, when the recalculation of the specific route is executed a predetermined number of times, and the suitability determining means determines that the specific route is not appropriate, the route calculation result determining means is It is conceivable to determine a specific route having the smallest cost value among the calculated specific routes as a route calculation result. In this way, it is possible to calculate an appropriate route while incorporating user preferences by recalculation within a predetermined number of times, and it is possible to improve user convenience.

  As shown in claim 4, the route calculation means, alternative route calculation means, suitability determination means, route calculation result determination means and route recalculation means in the navigation device according to any one of claims 1 to 3 are: It can be realized as a program for causing a computer to function. Therefore, the present invention can be realized as a program invention. In the case of such a program, for example, the program is recorded on a computer-readable recording medium such as an FD, MO, DVD-ROM, CD-ROM, or hard disk, and is used by being loaded into a computer and started up as necessary. be able to. In addition, the ROM or backup RAM may be recorded as a computer-readable recording medium, and the ROM or backup RAM may be incorporated into the computer for use.

  Embodiments to which the present invention is applied will be described below with reference to the drawings. The embodiments of the present invention are not limited to the following examples, and can take various forms as long as they belong to the technical scope of the present invention.

  FIG. 1 is a configuration diagram illustrating a configuration of the navigation device according to the embodiment. 2A is an explanatory diagram showing a recommended cost table, FIG. 2B is an explanatory diagram showing a toll road priority cost table, and FIG. 2C is a distance priority cost table. It is explanatory drawing which shows.

[Description of Configuration of Navigation Device 100]
As shown in FIG. 1, the navigation device 100 includes a position detector 1, a map data input device 6, an operation switch group 7, a control circuit 8 connected thereto, an external memory 9 connected to the control circuit 8, and a display device. 10. An external information input / output device 11 and a remote control sensor 12 are provided. The control circuit 8 is configured as a normal computer, and includes a well-known CPU, ROM, RAM, I / O, and a bus line for connecting these configurations.

[Description of Configuration of Position Detector 1]
The position detector 1 is a known geomagnetic sensor 2, gyroscope 3, distance sensor (vehicle speed sensor) 4, and GPS that detects the position and direction of the vehicle (vehicle traveling direction) based on radio waves from the satellite. For this purpose, a GPS receiver 5 is provided. Since these sensors 2, 3, 4, 5 have errors of different properties, they are configured to be used while being interpolated by a plurality of sensors. Depending on the accuracy, a part of the above may be used, and further, a steering rotation sensor, a wheel sensor of each rolling wheel, or the like may be used. The position detector 1 corresponds to position specifying means.

[Description of Configuration of Map Data Input Device 6]
The map data input device 6 is a device for inputting various data including so-called map matching data, map data, and facility data for improving the accuracy of position specification. The map data includes link information. As a recording medium of these data, other media such as a magnetic storage device such as a DVD, a CD-ROM, and a hard disk, or a memory card may be used. The map data input device 6 corresponds to a map data acquisition unit.

[Description of Configuration of External Memory 9]
The external memory 9 is composed of a nonvolatile memory and is used for storing various data. The external memory 9 is also used to store various link cost tables such as a recommended cost table, a toll road priority cost table, and a distance priority cost table as illustrated in FIG. The above-described link cost table is a list of distance correction coefficients (additional magnifications) for weighting the link cost set for each link, and each has a different tendency. Specifically, for each road type, each link cost table has a distance correction coefficient “easy to pass” to make it easy to pass the road type, a distance correction coefficient “to make it difficult to pass” the road type, And a normal distance correction coefficient “normal”. Among these, as illustrated in FIG. 2A, the recommended cost table gives priority to the expressway and the toll road among the expressway, the toll road or the general road, and the difference in the distance correction coefficient between the road types is high. It is set small. In addition, as shown in FIG. 2B, the toll road priority cost table gives priority to expressways and toll roads among expressways, toll roads, and general roads, and expressways, toll roads, and general roads. The difference between the distance correction coefficients is set large. In the distance priority cost table, as illustrated in FIG. 2C, the distance correction coefficients of the highway, the toll road, and the general road are set to be the same.

[Description of Configuration of Display Device 10]
The display device 10 is a color display device. On the screen of the display device 10, the vehicle current position mark input from the position detector 1, the map data input from the map data input device 6, and further displayed on the map. Additional data such as a guidance route and a touch switch can be displayed in an overlapping manner.

[Description of Configuration of External Information Input / Output Device 11]
The external information input / output device 11 receives an FM broadcast signal via a radio antenna (not shown), or receives a radio beacon signal and an optical beacon signal from a fixed station for VICS service arranged near the road. This received information is sent to the control circuit 8 for processing. Further, it is connected to a mobile phone (not shown) and has a function of acquiring information from an information center or connecting to the Internet and acquiring information from a server on the Internet.

[Description of configuration of remote control terminal 13, operation switch group 7 and the like]
Further, when the navigation apparatus 100 inputs the position of the destination from the remote control sensor 12 or the operation switch group 7 via the remote control terminal (hereinafter referred to as a remote controller) 13, the optimum route from the current position to the destination is obtained. There is also a so-called route guidance function that automatically selects and forms and displays a guidance route. As a method for automatically setting an optimal route, a method such as the Dijkstra method is known. As the operation switch group 7, for example, a touch switch integrated with the display device 10 and a mechanical switch group are used, and are used for various inputs.

[Description of Configuration of Control Circuit 8]
The control circuit 8 is configured around a well-known microcomputer comprising a CPU, ROM, RAM, I / O and a bus line connecting these configurations, and based on a program stored in the ROM and RAM, A map that calculates the current position of the vehicle as a set of coordinates and traveling directions based on each detection signal from the position detector 1 and displays a map or the like near the current position read via the map data input device 6 on the display device 10. Based on the display processing, the point data stored in the map data input device 6 and various data stored in the external memory 9, the destination facility is selected according to the operation of the operation switch group 7, the remote controller 13, etc., and the current position The route calculation process that automatically finds the optimal route from to the destination is performed. A technique such as the Dijkstra method is known as a technique for automatically setting an optimum route in this way.

  Further, the control circuit 8 performs a route guidance process for performing route guidance based on the guidance route obtained by the route calculation process. This route guidance is based on the result of route calculation and road shape data stored in the map data, intersection location information, crossing location information, etc. Calculate whether you need to turn right or turn left (ie, so-called navigation), and based on the calculation results, for example, a map of the current location, a highway schematic, or near the intersection near the intersection An enlarged view or the like is drawn and displayed on the display device 10. Further, audio output from an audio output device (not shown) is also used.

  The control circuit 8 corresponds to destination setting means, route calculation means, alternative route calculation means, suitability determination means, route calculation result determination means, and route recalculation means. The control circuit 8 corresponds to route guidance means together with the display device 10.

[Explanation of route calculation processing]
Next, the route calculation process executed by the control circuit 8 of the navigation device 100 will be described with reference to the flowchart of FIG. 3 and the explanatory diagram illustrating the route calculation process of FIG.

This processing is executed independently from other processing such as map display processing and route guidance processing when an accessory power supply (not shown) is turned on and power is supplied to the navigation device 100.
First, in the first step S110, a departure place is set. Based on each detection signal from the position detector 1, a current position is calculated as a set of coordinates and traveling directions, and the calculated current position is set as a starting point (see the starting point “S” in FIG. 4).

  In subsequent S120, a destination is set. Specifically, based on the point data input from the map data input device 6 and various data stored in the external memory 9, a destination facility is selected according to the operation of the operation switch group 7, the remote controller 13, etc. (FIG. (See destination 4 “E”.)

  In subsequent S130, the route from the departure point to the destination is searched using the recommended cost table. Specifically, a combination of nodes passing on the way from the departure point to the destination is calculated based on the road data input from the map data input device 6, and the calculated cost is calculated using a recommended cost table. Calculate the cost value. Then, the route (specific route) having the smallest cost value is selected from the routes. Hereinafter, the route searched in S130 is referred to as route A (see FIG. 4).

  In subsequent S140, a route from the departure place to the destination is searched using the distance priority cost table. Specifically, as in the previous S130, a combination of nodes passing on the way from the departure point to the destination is calculated based on the road data input from the map data input device 6, and the calculated combination is The cost value is calculated using the distance priority cost table. Then, the route having the smallest cost value (alternative route) is selected from the routes. Hereinafter, the route searched in S140 is referred to as a route B (see FIG. 4).

  In continuing S150, it is judged whether the path | route A is a detour. Specifically, it is determined whether the ratio of the cost value of the route A to the cost value of the route B is equal to or greater than a specified value. Note that the specified value may be experimentally set in advance, and in this embodiment, the specified value is set to 1.5. When the ratio of the cost value of the route A to the cost value of the route B is less than the specified value (S150: N), it is determined that the route A is not a detour and the route A is determined as a route calculation result (S200). ), This process is terminated. On the other hand, if the ratio of the cost value of the route A to the cost value of the route B is equal to or greater than the specified value (S150: Y), it is determined that the route A is a detour and the process proceeds to S160.

  In S160, it is determined whether or not the number of changes of the distance correction coefficient in S190, which will be described later, is greater than or equal to the specified number. Note that the specified number of times may be experimentally set in advance, and the specified number of times is set to 10 in this embodiment. Further, if this S160 is executed for the first time, the process proceeds to S170 as it is. If it is determined that the number of changes of the distance correction coefficient in S190 is less than the specified number (S160: N), the process proceeds to S170.

In subsequent S170, the above-mentioned route A is classified for each road type in units of links.
In subsequent S180, the above-mentioned route B is similarly classified on a link basis for each road type.
In subsequent S190, the distance correction coefficient included in the cost table used for the route calculation is corrected. Specifically, with respect to the recommended cost table used when calculating the route A, the distance correction coefficient corresponding to the road type that does not overlap the road type included in the route A among the road types included in the route B, Change from “normal” to “easy to pass”. Then, the process proceeds to S130. Thereafter, the processing of S130 to S190 is performed until it is determined that the route A is not a detour (S150: N) or until it is determined that the number of changes of the distance correction coefficient by S190 is equal to or greater than the specified number (S160: Y). Run repeatedly. If the transition to S130 is the second or subsequent time, in S130, the route is searched again for the route from the departure point to the destination using the recommended cost table after changing the distance correction coefficient ( (See “Route A after Recalculation” in FIG. 4). Also, if the transition to S190 is the second or later, in this S190, the distance correction coefficient that has not been changed when S190 is executed first is changed from “normal” to “easy to pass”.

  In S150, when it is determined that the ratio of the cost value of the route A to the cost value of the route B is less than the specified value (S150: N), it is determined that the route A is not a detour and the route A is routed. The calculation is executed and the process is terminated. In S160, when it is determined that the number of changes of the distance correction coefficient in S190 is equal to or greater than the specified number (S190: Y), the route having the smallest cost value among the routes A calculated so far is calculated as a route. The result is determined (S210), and this process is terminated.

  Note that the route calculation result calculated by the route calculation processing as described above is used in the route guidance processing or the like. Since the route guidance process is in accordance with a known technique, a detailed description thereof is omitted here.

[effect]
As described above, according to the navigation device 100 of the embodiment, when it is determined that the route A is a detour (S150: Y), the road included in the route B with respect to the recommended cost table referred to when the route A is calculated. Change the distance correction coefficient corresponding to the road type that does not overlap with the road type included in the specific route among the types from “Normal” to “Easy to pass”, and refer to the recommended cost table after the change for the route A Recalculate (S190, S120). In other words, in the route calculation process, the route A as the specific route is recalculated so as to reflect the tendency of the route B as the alternative route, so that the feature of the recommended cost table used when calculating the route A is utilized. The route can be corrected to the route incorporating the feature of the distance priority cost table used when calculating the route B, and an appropriate route can be calculated while incorporating the user's preference.

  Further, according to the navigation device 100 of the embodiment, when it is determined that the route A is a detour, when the recalculation of the route A is executed a prescribed number of times (S150: Y, S160: Y), the route calculated so far Since the route having the smallest cost value in A is determined as the route calculation result (S200), an appropriate route can be calculated while incorporating the user's preference by recalculation within a predetermined number of times. Convenience can be improved.

[Another embodiment]
(1) In the above embodiment, the control circuit 8 calculates the current position of the vehicle as a set of coordinates and traveling direction based on each detection signal from the position detector 1, and calculates a route using the calculated current position as the departure point. However, the present invention is not limited to this, and a point input from the remote control sensor 12 via the remote controller 13 or by the operation switch group 7 may be used as a departure point. In this case, the control circuit 8 corresponds to the departure place setting means.

  (2) For each link cost table of the above embodiment, three levels of distance correction coefficients are included for each road type, but this is not a limitation. For example, two levels of distance correction coefficients are included for each road type. Alternatively, four or more distance correction coefficients may be included for each road type.

  (3) In the above embodiment, the route A is calculated by referring to the recommended cost table. However, the present invention is not limited to this, and any link cost table reflecting the user's preference may be used. The route A may be calculated with reference to another link cost table such as a cost table or a distance priority cost table. The same applies to the link cost table referred to for calculating the route B.

  (4) In the route calculation process of the above embodiment, whether or not the route A is appropriate is determined by referring to the distance priority cost table to calculate the route B and determining whether or not the route A is a detour. However, the present invention is not limited to this, and when the link cost table other than the distance priority cost table is referred to calculate the route B, the route A is appropriate according to other criteria. It may be determined whether or not there is. For example, when route B is calculated with reference to the toll road priority cost table, whether route A is appropriate by determining whether it takes a long time to travel on route A or not. For example, it is judged whether or not. Even if it does in this way, there exists an effect similar to the said Example.

  (5) In the above embodiment, three types of link cost tables are prepared. However, the present invention is not limited to this. Two types of link cost tables may be prepared, and four or more types of link cost tables may be prepared. You may prepare.

  (6) In the route calculation process of the above embodiment, two types of routes (route A and route B) are compared. However, the present invention is not limited to this, and three or more types of routes may be compared. Even if it does in this way, there exists an effect similar to the said Example.

  (7) In the route calculation process of the above-described embodiment, the “specified value” for determining whether or not the route A is a detour and the “specified number” for determining the number of times the distance correction coefficient is changed in S190. Although it is set in advance, the present invention is not limited to this, and a value input from the remote control sensor 12 via the remote controller 13 or the operation switch group 7 may be used as a specified value or a specified number of times.

  (8) When there are a plurality of distance correction coefficients to be corrected in step S190 in the route calculation process of the above embodiment, the road length of the road type corresponding to the distance correction coefficient in either route A or route B is long. It is conceivable to preferentially correct the distance correction coefficient. In this way, since the effect of recalculation is increased, it is possible to calculate an appropriate route while incorporating user preferences with a smaller number of recalculations.

  (9) Also, in the above route calculation process, when the transition to step S190 is the second or later, in this S190, the distance correction coefficient that has not been changed when S190 is executed first is “normal”. However, the present invention is not limited to this, and the distance correction coefficient that was changed when S190 was previously executed may be changed again. For example, the first time is changed from “difficult to pass” to “normal”, and the second time is changed from “normal” to “easy to pass”. Even if it does in this way, there exists an effect similar to the said Example.

  (10) In step S190 in the route calculation process of the above embodiment, the recommended cost table used when calculating route A does not overlap with the road type included in route A among the road types included in route B. The distance correction coefficient corresponding to the road type is changed from “normal” to “easy to pass”. However, the distance correction coefficient is not limited to this, and the distance priority cost table used when calculating the route B is changed to the route A. The distance correction coefficient corresponding to the road type that does not overlap with the road type included in the route B among the included road types may be changed from “normal” to “not easy to pass”. However, when the distance correction coefficient of the distance priority cost table is changed in this way, the route B is calculated again using the distance priority cost table after the distance correction coefficient is changed in S140 to be subsequently transferred. . Even if it does in this way, there exists an effect similar to the said Example.

  (11) In the above embodiment, based on the data detected by the position detector 1, the control circuit 8 specifies the current vehicle position while interpolating the error of the current vehicle position. However, the position detector 1 is not necessarily required to specify the current position. For example, position information may be acquired from a roadside beacon or the like via the external information input / output device 11, and the current position may be specified based on the position information. Alternatively, a mobile phone, PHS, or the like may be connected to the navigation apparatus 100, and the current location may be specified by a position specifying function of the mobile phone, PHS, or the like.

It is a block diagram showing the structure of the navigation apparatus of an Example. (A) is explanatory drawing which shows the cost table for recommendation, (b) is explanatory drawing which shows the cost table for toll road priority, (c) is explanatory drawing which shows the cost table for distance priority. It is a flowchart explaining a route calculation process. It is explanatory drawing explaining a route calculation process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Position detector, 2 ... Geomagnetic sensor, 3 ... Gyroscope, 4 ... Distance sensor, 5 ... GPS receiver, 6 ... Map data input device, 7 ... Operation switch group, 8 ... Control circuit, 9 ... External memory, DESCRIPTION OF SYMBOLS 10 ... Display apparatus, 11 ... External information input / output apparatus, 100 ... Navigation apparatus

Claims (4)

A departure point setting means for setting a departure point;
Destination setting means for setting the destination;
Map data acquisition means capable of acquiring map data including information about links;
Link cost table storage means for storing a plurality of link cost tables in a list format of additional magnifications for weighting link costs set for each link;
The map data acquired by the map data acquisition unit and the link cost table storage unit store a specific route from the departure point set by the departure point setting unit to the destination set by the destination setting unit. A route calculation means for calculating by referring to a specific link cost table which is one of the link cost tables;
The map data acquired by the map data acquisition unit and the link cost table storage unit store an alternative route from the departure point set by the departure point setting unit to the destination set by the destination setting unit. An alternative route calculation means for calculating by referring to another link cost table having a tendency different from the specific link cost table in the link cost table;
Suitability judging means for judging whether or not the specific route is appropriate based on a ratio of the cost value of the specific route to the cost value of the alternative route;
If the specific route is determined to be appropriate by the suitability determining unit, a route calculation result determining unit that uses the specific route as a route calculation result;
A road type that does not overlap with a road type included in the specific route among road types included in the alternative route in the specific link cost table when the appropriate route determination unit determines that the specific route is not appropriate. The additional magnification corresponding to is corrected to a smaller value, and the specific route is recalculated by referring to the corrected specific link cost table by the route calculation means, or the specific route for the other link cost table The additional magnification corresponding to the road type that does not overlap with the road type included in the alternative route among the road types included in the alternative route is corrected to a larger value, and another link cost table after correction by the alternative route calculation unit is referred to Route recalculation for executing route recalculation processing for at least one of recalculating the alternative route And means,
Route guidance means for guiding the route calculation result determined by the route calculation result determination means;
A navigation device comprising:
When the route recalculation is performed by the route recalculation unit, the suitability determination unit determines again whether or not the specific route is appropriate,
The route calculation result determining means, when the route recalculation is performed by the route recalculation means, and when the specific route is determined to be appropriate by the suitability determination means, the route calculation result determination means As a result,
When the route recalculation unit determines that the specific route is not appropriate by the suitability determination unit after the route recalculation is performed by the route recalculation unit, the route recalculation unit performs the route recalculation process again. A navigation device characterized by executing. The navigation device according to claim 1, wherein
When the route recalculation unit recalculates the specific route by the route calculation unit or recalculates the alternative route by the alternative route calculation unit, when there are a plurality of additional magnifications to be corrected, A navigation device characterized by preferentially correcting an additional magnification having a long road length of a road type corresponding to the additional magnification in either a specific route or the alternative route. The navigation device according to claim 1 or 2,
The route calculation result determining means, when the recalculation of the specific route is executed a predetermined number of times, when the suitability determining means determines that the specific route is not appropriate, the specific calculation previously calculated by the route calculating means A navigation device characterized in that a specific route having the smallest cost value among routes is determined as a route calculation result.   A program for causing a computer to function as a route calculation unit, an alternative route calculation unit, a suitability determination unit, a route calculation result determination unit, and a route recalculation unit in the navigation device according to any one of claims 1 to 3.

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