JP2003130669A - Navigation system and program for method of searching route - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate an alternative route a driver wants. SOLUTION: The navigation system includes a route searching processing means 94 for acquiring a searched route by searching a route from a starting point to a destination, based on a link cost set for each link in navigation information, and an alternative route calculating processing means 95 for calculating an alternative route, based on searched result information representing a searched result by the route searching processing means 94. Weighting to each link cost in such a manner that the searched route is simply avoided is not performed. Consequently, for example, since a roundabout alternative route is precluded, an alternative a driver wants can be calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a program for a navigation system and a route search method.

[0002]

2. Description of the Related Art Conventionally, in navigation devices,
For example, GPS (Global Positioning System)
Based on the current position of the vehicle (own vehicle), that is, the current location, and the rotational angular velocity of the vehicle detected by the gyro sensor, that is, the turning angle,
The azimuth of the vehicle, that is, the azimuth of the own vehicle is detected, map data is read from the data recording unit, a map screen is formed on the display of the display unit, and the map screen is formed on the display of the display unit. The azimuth is output and displayed. Therefore, the driver who is the operator
The vehicle can be driven according to the map displayed on the map screen, the current location, and the vehicle direction.

Further, when the driver sets a destination and sets search conditions such as a recommended route, a toll road priority route, a general road priority route, and a distance priority route, the current position to the destination is determined based on the search conditions. The route is searched. Then, a search route display screen is formed on the display, and the searched route, that is, the search route is displayed on the search route display screen. Therefore, the driver
The vehicle can be driven according to the searched route.

By the way, for example, highways, toll roads,
Depending on the type of road, such as national roads, major local roads, prefectural roads, narrow streets, etc., turn right or left is prohibited. Depending on the number of items, various costs are set for each link or link, and when searching for a route, the search is performed from the departure side and the destination side, and the search from the departure side and the destination side. In the overlapping portion with the search from, the value obtained by adding the cost accumulated from the departure side and the cost accumulated from the destination side, that is, the cost addition value is calculated. Then, the route with the smallest added cost value is determined as the searched route.

[0005]

However, in the conventional navigation device, the searched route is not always the optimum route for the driver.

Therefore, it is possible to calculate another route (hereinafter referred to as "alternative route") which is at least partially different from the searched route. Therefore, the cost set for each link of the search route, that is, the link cost is weighted, the cost addition value is calculated again,
The route with the smallest added cost value is calculated as the alternative route.

However, in this method, each link cost is weighted so as to simply avoid the search route.
For example, a detour alternative route is calculated, and the alternative route desired by the driver cannot be calculated.

It is an object of the present invention to provide a program for a navigation system and a route search method, which solves the problems of the conventional navigation device and can calculate an alternative route desired by a driver. .

[0009]

To this end, in the navigation system of the present invention, an information recording section for recording navigation information, an information acquisition processing means for acquiring the navigation information from the information recording section, and a destination are provided. Destination setting processing means for setting, route search processing means for obtaining a search route by searching a route from a departure place to a destination based on a link cost set for each link in the navigation information, And an alternative route calculation processing unit for calculating an alternative route based on the search result information indicating the search result by the route search processing unit.

In another navigation system of the present invention, the alternative route calculation processing means further determines whether a predetermined link among the links of the alternative route overlaps with the link of the searched route, and duplicates. In this case, the alternative cost is calculated by weighting the link cost.

In yet another navigation system of the present invention, the alternative route calculation processing means further calculates a cost calculation processing means for calculating an alternative route candidate cost for each candidate route calculated based on the search result information.
And an alternative route determination processing means for determining, as an alternative route, one of the candidate routes having the lowest alternative route candidate cost.

[0012] In still another navigation system of the present invention, the cost calculation processing means may further be based on the additional magnification when a predetermined link among the links of the candidate route overlaps with the link of the searched route. Link costs are weighted.

In yet another navigation system of the present invention, the alternative route calculation processing means further resets the link cost based on the direction information of the search result information, and resets the cost. And a re-search processing unit that searches for an alternative route based on the link cost.

In still another navigation system of the present invention, the cost resetting processing means further comprises: when a predetermined link overlaps with a link of the searched route,
The link cost is weighted based on the addition rate.

In yet another navigation system of the present invention, the additional magnification is changed based on a cumulative overlap rate due to overlapping links.

In yet another navigation system of the present invention, the additional magnification is changed based on road traveling property.

In the program of the route search method of the present invention, the computer is provided with information acquisition processing means for acquiring navigation information from the information recording section, destination setting processing means for setting a destination, and each link of the navigation information. Based on the link cost set in, the route search processing means for searching the route from the starting point to the destination to obtain the searched route, and the search result information indicating the search result by the route search processing means It is caused to function as an alternative route calculation processing means for calculating a route.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram of a navigation system according to the first embodiment of the present invention.

In the figure, 16 is a data recording section as an information recording section for recording navigation information, 92 is information acquisition processing means for acquiring the navigation information from the data recording section 16, and 93 is a destination for setting a destination. The setting processing means 94 is a route search processing means for searching a route from a departure place to a destination to obtain a search route based on the link cost set for each link in the navigation information. It is an alternative route calculation processing unit that calculates an alternative route based on the search result information indicating the search result by the route search processing unit 94.

FIG. 2 is a block diagram showing a main part of the navigation system according to the first embodiment of the present invention.

In the figure, reference numeral 14 is a navigation device. The navigation device 14 includes a current position detection processing unit 15 for detecting the current position, an information recording unit for recording navigation information such as map data, road data, and search data. A data recording unit 16 as a recording medium, a navigation processing unit 17 arranged as a computer, functioning as various processing means, and performing various arithmetic processing such as navigation processing based on input information. An input unit 34 as a first input device, a display unit and a display unit 35 as a first output device, a voice input unit 36 as a second input device, a voice output unit 37 as a second output device, and The navigation processing unit 17 includes a communication unit 38 as a third input device and a third output device.
The vehicle speed sensor 41 is connected to.

The current position detection processing unit 15 includes a GPS 21, a geomagnetic sensor 22, a distance sensor 23, a steering sensor 24, a beacon sensor 25 as a current position detecting unit, a gyro sensor 26 as a direction detecting means, an altimeter (not shown) and the like. Become.

The GPS 21 detects the current position on the earth by receiving the radio wave generated by the artificial satellite, and the geomagnetic sensor 22 detects the vehicle direction by measuring the geomagnetism, and the distance sensor. Reference numeral 23 detects the distance between predetermined positions on the road. Examples of the distance sensor 23 include one that measures the rotation speed of a wheel (not shown) and detects the distance based on the rotation speed, one that measures the acceleration, and that integrates the acceleration twice to detect the distance. Can be used.

Further, the steering sensor 24 detects a steering angle, and the steering sensor 24 is as follows.
For example, an optical rotation sensor, a rotation resistance sensor attached to a rotating portion of a steering wheel (not shown),
An angle sensor or the like attached to the wheel is used.

Then, the beacon sensor 25 detects the current position by receiving position information from radio beacons, optical beacons and the like arranged along the road. The gyro sensor 26 detects a turning angle, and as the gyro sensor 26, for example, a gas rate gyro, a vibration gyro or the like is used. Then, the vehicle azimuth can be detected by integrating the turning angle detected by the gyro sensor 26.

The GPS 21 and the beacon sensor 25 can independently detect the current position.
Then, the current position can be detected by combining the distance detected by the distance sensor 23 with the own vehicle direction detected by the geomagnetic sensor 22 or the turning angle detected by the gyro sensor 26. Also,
The current position can also be detected by combining the distance detected by the distance sensor 23 and the steering angle detected by the steering sensor 24.

The data recording unit 16 includes a map data file, an intersection data file, a node data file,
A database including data files such as a road data file, a search data file, and a spot information data file is provided, and the display unit 3 is included in the map data file.
5, map data for displaying a map on a map screen formed on a display (not shown), intersection data relating to each intersection in the intersection data file, node data relating to node points in the node data file,
The road data file contains road data relating to roads, the search data file contains search data for searching a route, and the spot information data file contains information such as hotels, gas stations, parking lots, and tourist spot information in each region. Point information data regarding the facility is recorded as navigation information. The intersection condition data, the node data, the road data, and the search data constitute road condition data representing a road condition. The node data includes data indicating actual road branch points (including intersections, T-shaped roads, etc.), node points, and inter-node point links that connect the respective node points.

According to the road data, the width of the road itself, the gradient, the cant, the bank, the condition of the road surface, the number of lanes on the road, the place where the number of lanes decreases, the place where the width decreases, etc. For corners, the radius of curvature, intersection, T-junction, corner entrance, etc.
For downhill roads, uphill roads, etc., by road type, in addition to highways, toll roads such as highways, urban highways, toll roads, national roads,
General roads such as prefectural roads are shown. Further, the road data represents a railroad crossing, a highway entrance / exit installation road (ramp way), a highway / toll road toll gate, and the like.

In each data file, a guide map is output along the searched route and displayed on the searched route display screen set on the display of the display unit 35.
Various data for displaying characteristic photographs, frame drawings, etc. at an intersection or route, displaying the distance to the next intersection, the direction of travel at the next intersection, and displaying other guidance information Is recorded. The data recording section 16 also records various data for outputting predetermined information by the audio output section 37.

Further, the navigation processing unit 17 is
A CPU 31 as an arithmetic unit that controls the entire navigation device 14, and a RAM used as a working memory when the CPU 31 performs various arithmetic processes.
ROM 3 as a recording medium in which various programs for searching a route to a destination, guiding a route, determining a specific section, etc. are recorded in addition to 32 and a control program.
3 and the navigation processing unit 17
The input unit 34, the display unit 35, the voice input unit 36, the voice output unit 37, and the communication unit 38 are connected to the above. The CPU 31 also includes an MPU.

The data recording unit 16 and the ROM 3
3 is composed of a magnetic core, a semiconductor memory, and the like, which are not shown. In addition, the data recording unit 16 and the ROM 3
Various recording media such as a magnetic tape, a magnetic disk, a flexible disk, a magnetic drum, a CD, an MD, a DVD, an optical disk, an MO, an IC card, and an optical card can be used as the recording medium 3.

In the present embodiment, the ROM 33
Various programs are recorded in the data recording unit 16
Although various kinds of data are recorded in, the programs, data, etc. can be recorded in the same external recording medium. In this case, for example, a flash memory (not shown) may be provided in the navigation processing unit 17, and the program, data, etc. may be read from the external recording medium and written in the flash memory. Therefore, the programs, data, etc. can be updated by exchanging the external recording medium. Further, a program for controlling the automatic transmission control device (not shown) and the like can be recorded in the external recording medium. In this way, start the programs recorded on various recording media,
Various processing can be performed based on the data.

Further, the communication section 38 includes, for example, traffic information including traffic congestion information, regulation information, parking lot information, traffic accident information, D-GPS information for detecting a detection error of the GPS 21, and the like. It receives data transmitted from various base stations, and receives position information from radio beacon devices, optical beacon devices, etc. arranged along roads via radio beacons, optical beacons, etc.

The input unit 34 is for correcting the current position at the start of traveling and for inputting the starting point and the destination, and is displayed as an image on the screen set on the display. It consists of various keys and operation switches for operation menus. Therefore, input can be performed by touching (pressing) the operation switch.
As the input unit 34, a keyboard, a mouse, a bar code reader, a light pen, which is provided separately from the display unit 35,
It is also possible to use a remote control device or the like for remote operation.

On various screens formed on the display, operation guides, operation menus, operation key guides, a search route from the present location to a destination, guide information along the search route, and the like are displayed. . As the display unit 35, a display such as a CRT display, a liquid crystal display or a plasma display can be used, or a hologram device that projects a hologram on the windshield of a vehicle can be used.

The voice input section 36 is composed of a microphone (not shown) or the like, and can input necessary information by voice. Furthermore, the audio output unit 37
Is provided with a voice synthesizer and a speaker (not shown), and outputs sound information, for example, guide information composed of voices synthesized by the voice synthesizer, gear shift information, and the like from the speaker.
In addition to the voice synthesized by the voice synthesizer,
It is also possible to output various sounds, various guidance information recorded in advance on a tape, a memory or the like from a speaker.

Next, the navigation device 14 having the above structure
The operation of will be described.

First, when the driver, who is an operator, operates the input unit 34 to activate the navigation device 14, the navigation initialization processing means (not shown) of the CPU 31 operates as follows.
Performs navigation initialization processing. Subsequently, the CPU 31 uses the GPS
The present location detected by 21 and the gyro sensor 2
The vehicle direction detected by 6 is read, and C
The information acquisition processing means 92 (FIG. 1) of the PU 31 performs the information acquisition processing, refers to the map data file, the road data file, the search data file and the like from the data recording unit 16 and reads the map data, the road data, the search data and the like. The navigation information is read to obtain the information. In the present embodiment, the information acquisition processing unit 92 reads the navigation information from the data recording unit 16 and acquires it, but the communication unit 38 can also receive and acquire the navigation information.

Next, the map display processing means (not shown) of the CPU 31 performs map display processing to form a map screen on the display, and displays a map around the current location on the map screen according to the map data. , The current location and the vehicle direction are displayed.

When the navigation device 14 is used as a route search device, the driver inputs the input unit 34.
When is operated to input the destination, the destination setting processing means 93 of the CPU 31 performs the destination setting processing to set the destination. It should be noted that the departure place can be set if necessary. Next, when the driver operates the input unit 34 to set the search condition, the route search processing means 94 of the CPU 31 performs the route search process according to the search condition, reads the search data, and based on the search data. , Search the route from the starting point to the destination, which is represented by the current location.

Subsequently, a search route display processing unit (not shown) of the route search processing unit 94 performs a search route display process to form a search route display screen on the display,
The searched route is displayed on the searched route display screen. Therefore, the driver can drive the vehicle according to the searched route.

By the way, for example, highways, toll roads,
Depending on the road type such as national roads, main local roads, prefectural roads, narrow streets, etc., there are various link costs for each link that constitutes the road depending on the prohibition of turning left and right, the presence or absence of traffic restrictions such as one-way It is set, the route search processing means 94, when searching for a route, performs a search from the departure side and the destination side, and in the overlapping portion of the search from the departure side and the search from the destination side, The cost addition value of the link cost accumulated from the departure side and the link cost accumulated from the destination side is calculated. Then, the route search processing means 94 determines a route having the minimum cost addition value as a search route.

The search conditions include a recommended route, a toll road priority route, an ordinary road priority route, a distance priority route, etc. When the toll road priority route is set, the link cost of the high speed / toll road is generally set. When the route cost is set smaller than the road link cost and the distance priority route is set, the link cost of the road having a large width is set smaller than the link cost of the road having a small width.

Next, a method of determining a search route will be described.

FIG. 3 is a diagram showing a sample network according to the first embodiment of the present invention.

In this case, the sample network is composed of nodes a to p corresponding to intersections and links corresponding to roads connecting the nodes a to p. Node a is closest to the departure point and node f is closest to the destination. The numerical value attached to each link is each link cost Cj (j = 1, 2, ...) Set by the size of the link length.

The coordinates of the nodes a to p, the node number assigned to each node, the link number assigned to each link, the link length, the link cost Cj, etc. are recorded in the data recording unit 16 as search data. It

The cost is set between links according to the link length, the road type, the road width, the number of lanes, the link cost set for each link, and the presence or absence of traffic regulation. The link cost C is set depending on the size of the link length in order to simplify the description in the present embodiment.
Consider only j.

Next, the process of searching for a route from the departure side and the destination side by the Dijkstra method will be described.

FIG. 4 is a first diagram for explaining costing in the first embodiment of the present invention, and FIG. 5 is a first diagram, FIG. 5 for explaining a search state in the first embodiment of the present invention. 6
Is a second diagram for explaining the search state in the first embodiment of the present invention, FIG. 7 is a second diagram for explaining the costing in the first embodiment of the present invention, and FIG. 8 is for the present invention. FIG. 9 is a third diagram for explaining a search state according to the first embodiment.
Is a fourth diagram for explaining the search state in the first embodiment of the present invention, FIG. 10 is a third diagram for explaining the costing in the first embodiment of the present invention, and FIG. 11 is for the present invention. A fifth diagram for explaining a search state in the first embodiment,
FIG. 12 is a sixth diagram for explaining a search state in the first embodiment of the present invention, FIG. 13 is a fourth diagram for explaining costing in the first embodiment of the present invention, and FIG. 14 is a book. A seventh example for explaining the search state in the first embodiment of the invention.
FIG. 15 is a diagram showing a search result from the departure place side in the first embodiment of the present invention, and FIG. 16 describes costing from the departure place side in the first embodiment of the present invention. FIG. 17 is a diagram showing a search result from the destination side in the first embodiment of the present invention, and FIG. 18 is a diagram explaining cost addition from the destination side in the first embodiment of the present invention FIG. 19 is a diagram showing a search route in the first embodiment of the present invention.

In this case, the route search processing means 94, for each of the nodes a to p, the costs Csa to Csp in which the link costs Cj from the starting point which is the starting point of the costing to each of the nodes a to p are accumulated, and Similarly, the accumulated costs Cea to Cep from the destination, which is the starting point of costing, to the nodes a to p are used as cost information, and the node immediately before costing is performed, that is, the immediately preceding node is calculated as direction information. . Then, the cost information and the direction information constitute search result information indicating the search result by the route search processing means 94.

To this end, the route search processing means 94
Reads the search data from the data recording unit 16,
The node number, link number, link length, link cost Cj, etc. recorded as the search data are read. Subsequently, the route search processing means 94 assigns a cost to the node a closest to the departure place, as shown in FIG. In this case, node a is closest to the starting point, so
The cost Csa is 0, and since it is the first node to be costed, there is no immediately preceding node.

Next, the route search processing means 94 is operated as shown in FIG.
, The node with the lowest cost of the costed nodes, a, is detected as the minimum node, and then the search can be extended as shown in FIGS. 6 and 7. Costs are applied to the nodes in the direction of, that is, nodes b and g in this embodiment. In this case, the costs Csb and Csg of the nodes b and g are 10 and 6, respectively, and the immediately preceding nodes are a.

Then, the route search processing means 94, as shown in FIG.
The node g having the smallest cost of g is detected as the minimum node, and as shown in FIGS. 9 and 10, nodes in all directions in which the search can be extended from the minimum node, in the present embodiment, A cost is assigned to the node h. In this case, the cost Csh of the node h is 21
And the immediately preceding node is g.

Note that a node whose cost has been calculated once (once) as the minimum node and whose cost has been calculated (calculated) is not subject to costing.

Next, the route search processing means 94 is operated as shown in FIG.
As shown in FIG.
The node b with the lowest cost of h is detected as the minimum node, and as shown in FIGS. 12 and 13, for nodes c, h, and l in all directions that can extend the search from the minimum node. Make a cost. In this case, the costs Csc, Csh, and Csl of the nodes c, h, and l are 20, 13, and 17, respectively, and the immediately preceding nodes are all b.
Is. Here, although the cost is once applied to the node h from the node g, the cost from the node g is 21, whereas the cost from the node b is 13.
The cost is overwritten because it is less than the cost from node g.

Next, the route search processing means 94 is operated as shown in FIG.
As shown in FIG.
The node h having the minimum cost is detected from h and l as the minimum node.

Then, the route search processing means 94 repeats such costing and detection of the minimum node,
Finally, the search result from the departure side as shown in FIGS. 15 and 16 is obtained.

That is, as shown in FIGS. 15 and 16, the costs Csa to Csp of the nodes a to p are 0, 10, 20, 30, 40, 50, 6, 13, 2 respectively.
3, 33, 43, 17, 26, 36, 46, 59, and the immediately preceding nodes are-, a, b, c, d, respectively.
e, a, b, h, i, j, b, c, m, n, f.

The route search processing means 94 also repeats costing and minimum node detection from the destination side to obtain the search result from the destination side as shown in FIGS.

That is, as shown in FIGS. 17 and 18, the costs Cea to Cep of the nodes a to p are 50, 40, 30, 20, 10, 0, 56, 43, respectively.
33, 24, 14, 46, 36, 26, 16, 9 and the immediately preceding nodes are b, c, d, e, f, respectively.
-, A, i, c, k, e, m, n, o, e, f.

Next, the route search processing means 94 overlaps the search from the departure side with the search from the destination side, in the present embodiment, from the departure side of each of the nodes a to p. Cost addition values Cta to Ctp with the costs Csa to Csp and the costs Cea to Cep from the destination side are calculated. In the present embodiment, the cost added values Cta to Ctp of the nodes a to p are 50, 50 and 5, respectively.
0, 50, 50, 50, 62, 56, 56, 57, 5
7, 63, 62, 62, 62, 68.

Then, the route search processing means 94 uses the node a to which the cost added value Cta to Ctp becomes the minimum.
Starting from f (the added cost values Cta to Ctf are 50), the route is traced to the starting point side and the destination side based on the direction information of the search result (in FIG. 19, the node c is the starting point). The case is shown.). In this way, the route passing through the nodes a to f as shown in FIG. 19 can be determined as the search route F1.

Then, the searched route F1 is displayed on the searched route display screen.

By the way, the searched route F1 is not always the optimum route for the driver. Therefore, when the driver touches a member for displaying the alternative route displayed on the search route display screen, for example, an alternative route search key, the alternative route calculation processing means 95 of the CPU 31
An alternative route calculation process is performed to calculate an alternative route that is at least partially different from the searched route F1.

Next, the operation of the alternative route calculation processing means 95 will be described.

FIG. 20 is a flowchart showing the operation of the alternative route calculation process according to the first embodiment of the present invention, FIG.
1 is a diagram showing a subroutine of cost calculation processing in the first embodiment of the present invention, FIG. 22 is a first diagram showing a calculation example of cost calculation processing in the first embodiment of the present invention, and FIG. It is a 2nd figure which shows the example of calculation of the cost calculation process in the 1st Embodiment of this invention.

In this case, the alternative route calculation processing means 95 (FIG. 1) of the CPU 31 (FIG. 2) performs the alternative route calculation process, and the preset number of routes (hereinafter referred to as “the number of candidate routes”).
Say. ) N alternative route candidates, ie, candidate route G
i (i = 1, 2, ..., N) is calculated.

Therefore, the alternative route calculation processing means 9
5 detects the node having the smallest cost addition value next to the nodes a to f as the next minimum node. In the present embodiment, the nodes next to the nodes a to f are h and i,
The added cost values Cth and Cti of the nodes h and i are 56. Then, the alternative route calculation processing means 95 follows the route from the nodes h and i as the starting point to the departure side and the destination side based on the direction information of the search result (in FIG. 22, the node i is 22. As shown in FIG. 22, nodes a, b, h,
A candidate route G1 passing through i, c, d, e, f is searched.

Next, the alternative route calculation processing means 95
The node having the smallest cost addition value next to the nodes h and i is detected as the next smallest node. In this embodiment, the next smallest nodes after the nodes h and i are j and k,
The added cost values Ctj and Ctk of the nodes j and k are 57. Then, the alternative route calculation processing unit 95 traces the route from the nodes j and k to the starting point side and the destination side based on the direction information of the search result. in this case,
A candidate route G2 (not shown) passing through the nodes a, b, h, i, j, k, e, f can be searched.

Next, the alternative route calculation processing means 95
The node having the smallest cost addition value next to the nodes j and k is detected as the next smallest node. In the present embodiment, the nodes next to the nodes j and k are g and m to o, and the cost addition values Ctg and Ctm to the nodes g and m to o.
Cto is 62. Then, the alternative route calculation processing unit 95 traces the route to the departure point side and the destination side based on the direction information of the search result, starting from the nodes g and m to o (in FIG. 23, the node). 23, a candidate route G3 passing through the nodes a, b, c, m, j, n, o, e, and f is searched for, as shown in FIG.

By repeating the above operation,
It is possible to calculate the candidate routes Gi of the number n of candidate routes.

Subsequently, the cost calculation processing means (not shown) of the alternative route calculation processing means 95 performs the cost calculation processing, and weights the link cost Cj set for each link on the candidate route Gi for each candidate route Gi. Then, the corrected link cost Crj (j = 1, 2, ...) Is calculated.

Therefore, the cost calculation processing means is
Search data is read from the data recording unit 16 and
Each link cost Cj in the sample network is read. Next, the cost calculation processing means determines whether or not each link on each of the candidate routes Gi overlaps with the corresponding link on the search route F1, and if they overlap, the link cost Cj is set to the additional magnification x. The multiplied value is used to calculate the duplicated link cost Cxj (j = 1, 2, ...) Cxj = Cj · x, the duplicated link cost Cxj is added to the link cost Cj, and the modified link cost Crj Crj = Cj · ( 1 + x) is calculated. In this way, the link cost Cj is weighted based on the additional magnification x.

Subsequently, the cost calculation processing means calculates the total of the modified link costs Crj for each candidate route Gi as the alternative route candidate cost ΣCi (i = 1, 2, ..., N) ΣCi = Cr1 + Cr2 +. To do.

The alternative route determination processing means (not shown) of the alternative route calculation processing means 95 performs the alternative route determination processing, determines the alternative route candidate cost ΣCi as the alternative route, and outputs it.

Then, an alternative route display processing means (not shown) of the CPU 31 performs an alternative route display process, forms an alternative route display screen on the display, and displays the alternative route on the alternative route display screen. Therefore, the driver can drive the vehicle along the alternative route.

Next, an example of cost calculation of the candidate routes G1 to G3 will be described.

As shown in FIG. 22, the candidate route G1 overlaps with the search route F1 (FIG. 19) on the links ab, cd, de, and ef, and the links bh, h-. i, i
-C does not overlap with the search route F1.

Therefore, the alternative route candidate cost ΣC1
Is ΣC1 = 10 × (1 + 0.8) + 3 + 10 + 3 + 10 ×
(1 + 0.8) + 10 × (1 + 0.8) + 10 × (1+
0.8) = 88.

The candidate route G2 is linked to links ab and e-.
In f, it overlaps with the search route F1, and links b-h and h-
i, i-j, j-k, and k-e do not overlap with the search route F1.

Therefore, the alternative route candidate cost ΣC2
Is ΣC2 = 10 × (1 + 0.8) + 3 + 10 + 10 + 10
It becomes + 4 + 10 × (1 + 0.8) = 73.

As shown in FIG. 23, the candidate route G3 overlaps with the search route F1 on the links ab, bc, and ef, and the links cm, m-n, n-o, and o-. e does not overlap with the search route F1.

Therefore, the alternative route candidate cost ΣC3
Is ΣC3 = 10 × (1 + 0.8) + 10 × (1 + 0.8)
+ 6 + 10 + 10 + 6 + 10 × (1 + 0.8) = 86. Therefore, since the alternative route candidate cost ΣC2 is smaller than the alternative route candidate costs ΣC1 and ΣC3, the candidate route G2 is determined as the alternative route.

In this way, the candidate route Gi is calculated based on the search result in the route search processing, and each candidate route G is calculated.
Since the link cost Cj of i is weighted, each link cost Cj is not weighted so as to simply avoid the search route F1. Therefore, for example, a detour alternative route is not calculated, so that an alternative route that the driver desires can be calculated.

Next, the flowchart of FIG. 20 will be described. Step S1 Infinite (∞) is set to the minimum cost. Step S2: Start a loop based on the number of candidate routes n. In step S3, cost calculation processing is performed. In step S4, it is determined whether the alternative route candidate cost ΣCi is the minimum. When the alternative route candidate cost ΣCi is the minimum, the process proceeds to step S5, and when it is not the minimum, the process proceeds to step S6. Step S5: Record the alternative route. Step S6 The loop for the number n of candidate routes is ended. In step S7, the alternative route is determined and output, and the process ends.

Next, the flowchart of FIG. 21 will be described. Step S3-1: 0 is set to the alternative route candidate cost ΣCi. Step S3-2 The loop by the link on the candidate route Gi is started. Step S3-3 The link cost Cj is read. Step S3-4: It is judged whether or not it overlaps with the link on the search route F1. When it overlaps with the link on the search route F1, the process proceeds to step S3-5, and when it does not overlap, the process proceeds to step S3-7. Step S3-5: The duplicate link cost Cxj is set to a value obtained by multiplying the link cost Cj by the additional magnification x. Step S3-6 The overlapping link cost Cxj is added to the link cost Cj. Step S3-7 The alternative route candidate cost ΣCi is calculated. Step S3-8 The loop by the link on the candidate route Gi is ended and the process returns.

By the way, in the above-mentioned embodiment, if the additional magnification x is too small, the alternative route becomes almost equal to the search route F1, and if the additional magnification x is too large, the alternative route does not search the search route F1 at all. Avoid it. Therefore, it becomes extremely difficult to set the additional magnification x.

Therefore, when each link on each of the candidate routes Gi overlaps with the corresponding link on the search route F1,
The additional magnification x is changed based on the cumulative overlap rate based on the starting point or the destination, and the additional magnification x is increased as the distance from the starting point side or the destination side increases. The second embodiment will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by giving the same code | symbol.

FIG. 24 is a diagram showing a calculation example of the cost calculation processing in the second embodiment of the present invention.

In this case, if the total length of the search route F1 (FIG. 19) is Lf and the link length of the links forming the search route F1 is Lk (k = 1, 2, ..., M), Ratio of each link length Lk to the length Lf γk (k = 1,
2, ..., M) becomes γk = Lk / Lf. Therefore, the cost calculation processing means compares the candidate route Gi and the search route F1 with reference to the departure point,
When overlapping links exist, the ratios γk of the overlapping links are sequentially added to calculate the cumulative overlapping rate, and the additional magnification x is calculated based on the cumulative overlapping rate.

For example, in FIG. 24, the links a-b, b-c, cd-de, de-e, e- which constitute the search route F1.
When the link lengths Lk of f are equal to each other (k = 1, 2, ..., 5), the ratio γk of each link length Lk to the length Lf.
(K = 1, 2, ..., 5) becomes γk = 0.2. Then, based on the departure point, the candidate route G11
When the search route F1 is compared with the search route F1, the candidate route G11 and the search route F1 overlap in the links ab and ef.
Therefore, the additional magnification x in the links a-b has a cumulative overlap rate of 0.2, so that x = 0.2, and the additional magnification x in the links ef has a cumulative overlap rate of 0.4. Therefore, x is set to 0.4.

When the target value is used as a reference, the link e
The additional multiplication factor x in −f is set to x = 0.2 because the cumulative overlapping ratio is 0.2, and the additional multiplication factor x in link a−b is 0.4 because the cumulative overlapping ratio is 0.4. It is set to 0.4.

As described above, since the cumulative overlap rate is set to the additional magnification x, when the ratio of the candidate route G11 and the search route F1 matching is small, the additional magnification x has no effect and the alternative route candidate cost ΣCi. However, if the rate at which the candidate route G11 and the searched route F1 coincide with each other becomes large, the candidate cost ΣCi is greatly affected by the additional magnification x.
Grows.

Therefore, it is possible to suppress the search for an alternative route that is substantially the same as the search route F1, or an alternative route that does not pass through the search route F1 at all.

In the present embodiment, the additional magnification x
Can be changed between 0 and 1, but the degree of freedom of the additional magnification x can be further increased by another coefficient. For example, when the cumulative overlap rate is δ and the free coefficients are α _i and β _i , the additional magnification x is

[0098]

[Equation 1] It can be expressed as.

Next, a third embodiment of the present invention will be described.

FIG. 25 is a diagram showing a calculation example of the cost calculation process in the third embodiment of the invention.

By the way, for example, highways, toll roads,
Since the ferry route and the like are easier to travel than other roads, the link cost Cj set for the link is made smaller than other roads having the same link length Lk. Therefore, if the additional magnification x on a road with a low link cost Cj, such as a highway, a toll road, or a ferry route, that is, a low-cost road is equal to the additional magnification x on another road, a low-cost road is avoided. Becomes difficult, and it becomes impossible to search for an appropriate alternative route. Therefore, the cost calculation processing means increases the additional magnification x on the low cost road so that it can be avoided even on the low cost road. Therefore, an appropriate alternative route can be searched.

In FIG. 25, the links ab, bc,
Links c-d and d-e of cd, d-e, and e-f
If the road type is a highway, the links ab, b-
The additional magnification x in c and ef is set to x = 0.4, and the additional magnification x in the links cd and de is set to x = 0.8.

The additional magnification x can be increased on a low-cost road by changing the additional magnification x according to road attributes such as road width and number of lanes.

As described above, since the additional magnification x can be changed based on the road traveling property according to the road type, the road attribute, etc., an appropriate alternative route can be searched.

Next, a fourth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by giving the same code | symbol.

FIG. 26 is a flow chart showing the operation of the alternative route calculation processing in the fourth embodiment of the present invention, FIG.
7 is a diagram showing a subroutine of a departure place side cost resetting process in the fourth embodiment of the present invention, FIG. 28 is a diagram explaining costing from the departure place side in the fourth embodiment of the present invention, FIG. 29 is a diagram showing a sample network according to the fourth embodiment of the present invention, FIG. 30 is a diagram showing a search result from the departure point side according to the fourth embodiment of the present invention, and FIG. 31 is a diagram showing the present invention. FIG. 32 is a diagram showing search results from the destination side in the fourth embodiment, and FIG. 32 is a diagram showing a calculation example of cost calculation processing in the fourth embodiment of the present invention.

In this case, the route search processing means 94 (FIG. 1) of the CPU 31 (FIG. 2) performs route search processing to search and determine the searched route F1. Along with this, the route search processing means 94, as shown in FIG. 28, for each of the nodes a to p, from the starting point, which is the starting point of costing, to each node a.
Up to p accumulated costs Csa to Csp, and also from the destination, which is the starting point for costing, to each node ap
The accumulated costs Cea to Cep up to are calculated as the cost information, and the node immediately before the cost is assigned, that is, the immediately preceding node as the first direction information,
The node to which the cost is added, that is, the additional node is calculated as the second direction information. Then, the cost information and the first and second direction information constitute search result information indicating a search result by the route search processing means 94.

Then, the alternative route calculation processing means 95 of the CPU 31 performs the alternative route calculation process to obtain the searched route F1.
And an alternative route that is at least partially different from.

Therefore, the cost resetting processing means (not shown) of the alternative route calculation processing means 95 resets the link cost Cj set for each link. And, the cost resetting process on the departure place side of the cost resetting processing means,
The origin side cost resetting process is performed, based on the search result of the route search process, the node a having the smallest cost among the nodes to which the cost has been added is detected as the minimum node, and the search is further extended. The direction of nodes b and g, which is the direction, is detected.

Next, the starting point side cost reset processing is as follows.
Search data is read from the data recording unit 16 and
The link costs Cj (10 and 6 in this case) of the links ab and ag in the directions of the nodes b and g in the sample network are read.

Next, in the starting point side cost resetting process, it is judged whether or not the links ab and ag in the directions of the nodes b and g and the links on the search route F1 overlap, and if they do overlap. , A value obtained by multiplying the link cost Cj by the additional scale factor x is calculated as a duplicate link cost Cxj (j = 1, 2, ...) Cxj = Cj · x, and the duplicate link cost Cxj is added to the link cost Cj, The corrected link cost Crj Crj = Cj · (1 + x) is calculated. In this case, if the additional magnification x is 0.8,
Since the link ab overlaps with the link on the search route F1, the modified link cost Crj of the link ab is Crj = 10 × (1 + 0.8) = 18 as shown in FIG. Since a-g does not overlap with the link on the search route F1, the corrected link cost Crj of the link a-g.
Becomes Crj = 6.

Then, in the starting point side cost reset processing, the corrected link cost Crj (18, 6) is reset as the link cost Cj. In this way, the additional magnification x
The link cost Cj is weighted based on

Subsequently, in the starting point side cost reset processing, the nodes b and g for which the link cost Cj has been reset.
The node g with the smallest cost is detected as the minimum node, and the direction in which the search is extended is detected based on the direction information indicating the search result of the route search processing. In this case, since there is no direction to extend the search for the node g, the starting point side cost reset processing is the node b having the next lowest cost among the nodes b and g for which the cost has been reset. Is detected as the minimum node, and further, based on the direction information, the node c that is the direction to extend the search,
The directions of h and l are detected.

In the starting point side cost resetting process, the links b-c, b-h, b-l are linked by the method described above.
Modified link cost Crj (in this case 36, 21, 2
5) is calculated, the link cost Cj is reset, and the node h having the smallest cost among the nodes c, h, and l for which the link cost Cj is reset is detected as the minimum node, and The direction in which the search is extended is detected based on the direction information.

When the above processing is repeated and the link cost Cj is reset from the starting point side to the destination side,
A search result as shown in FIG. 30 can be obtained.

Subsequently, in the destination side cost resetting process of the cost resetting processing means, the destination side cost resetting process is performed, and the link cost Cj from the destination side to the starting place side is based on the direction information. Is reset, the search result as shown in FIG. 31 is obtained.

Next, the re-search processing means (not shown) of the alternative route calculation processing means 95 performs the re-search processing and substitutes the route from the departure place to the destination based on the reset link cost Cj. Search as a route. for that reason,
The re-search processing means, the overlapping portion of the search from the departure side and the search from the destination side, in the present embodiment,
Costs Csa to Csp after resetting of the nodes a to p from the departure side and cost addition values Cta with the costs Cea to Cep after resetting from the destination side
~ Calculate Ctp.

Then, the re-search processing means calculates the nodes j and k (the cost addition values Ctj and Ctk are 73) where the cost addition values Cta to Ctp are the minimum,
Starting from the nodes j and k, the route is traced to the starting point side and the destination side based on the direction information (in FIG. 32, the case where the node k is the starting point is shown). In this way, the alternative route G21 passing through the nodes a, b, h, i, k, e, f as shown in FIG.
Can be searched. Then, the alternative route calculation processing means 95 outputs the alternative route G21.

As described above, in the present embodiment, since the link cost Cj is reset based on the direction information obtained by the route search processing, the search route F1 is simply used.
Each link cost Cj is not weighted so as to avoid Therefore, for example, a detour alternative route is not calculated, so that an alternative route that the driver desires can be calculated.

Next, the flowchart of FIG. 26 will be described. In step S11, the starting point side cost reset process is performed. In step S12, the destination side cost resetting process is performed. Step S13: Search for an alternative route. In step S14, the alternative route is output and the process ends.

Next, the flowchart of FIG. 27 will be described. Step S11-1 The minimum node is detected based on the search result. Step S11-2: Start a loop for resetting the link cost Cj. Step S11-3: It is judged whether or not the loop is the first one. If the loop is the first time, step S11
If it is not the first time, go to step S11-4. Step S11-4 Detects the minimum node among the nodes for which the link cost Cj is set. Step S11-5: Detect the direction and the number of extending the search based on the direction information. Step S11-6: Start a loop depending on the number of directions to extend the search. Step S11-7: Read the link cost Cj. Step S11-8: It is judged whether the link in the direction of extending the search overlaps with the link on the search route F1. If the link in the direction of extending the search overlaps with the link on the search route F1, the process proceeds to step S11-9, and if not, the process proceeds to step S11-11. Step S11-9: Calculate the duplicate link cost Cxj. Step S11-10 Add the duplicate link cost Cxj to the link cost Cj. Step S11-11 The link cost Cj is reset. Step S11-12: End the loop depending on the number of directions to extend the search. Step S11-13: The loop for resetting the link cost Cj is ended, and the process returns.

By the way, in the fourth embodiment, the cost resetting process is performed based on the additional node. However, in the route searching process, immediately before the cost is calculated as the cost is added. It is also possible to perform cost reset processing based on the node.

Next explained is the fifth embodiment of the invention in which the cost resetting process is performed based on the immediately preceding node.

FIG. 33 is a flow chart showing a subroutine for the cost resetting process on the departure point side in the fifth embodiment of the present invention.
FIG. 34 is a second diagram showing a subroutine of the starting point side cost resetting process in the fifth embodiment of the invention.

In this case, the cost resetting processing means detects all the nodes connected to the cost-added node in the route search processing, and determines the immediately preceding node for each detected node. To detect. Then, the cost resetting processing unit determines whether or not the immediately preceding node is the node, that is, the own node, and when it is the own node, resets the link cost Cj.

For example, when the own node is a, the cost resetting processing means detects all the nodes b and g connected to the node a, and the immediately preceding node is detected for each of the detected nodes b and g. To calculate. In this case, since the node immediately preceding the nodes b and g is a, the cost resetting processing means calculates the duplicate link cost Cxj of the links ab and ag, and calculates the corrected link cost Crj.

Next, the flowchart will be described. Step S11-21 The minimum node is detected based on the search result. Step S11-22: Start a loop for resetting the link cost Cj. Step S11-23: It is judged whether or not the loop is the first time. If the loop is the first time, step S1
1-25, if it is not the first time, step S11-24
Proceed to. Step S11-24: The smallest node among the nodes for which the link cost Cj is set is detected. Step S11-25: Start a loop depending on the number of connected nodes. Step S11-26 The immediately preceding node is detected based on the search result for the connected node. Step S11-27: It is judged whether the immediately preceding node is the own node. If the immediately preceding node is the own node, the process proceeds to step S11-28, and if it is not the own node, the process returns to step S11-25. Step S11-28 The link cost Cj is read. Step S11-29: It is judged whether or not the link in the direction to extend the search overlaps with the link on the search route F1.
If the link in the direction to extend the search overlaps with the link on the search route F1, the process proceeds to step S11-30, and if not, the process proceeds to step S11-31. Step S11-30: Calculate the duplicate link cost Cxj. Step S11-31 Add the duplicate link cost Cxj to the link cost Cj. Step S11-32 Reset the link cost Cj. Step S11-33 Terminates the loop depending on the number of connected nodes. Step S11-34 Terminates the loop for resetting the link cost Cj, and returns.

Next explained is the sixth embodiment of the invention in which a database can be transmitted and received between the information base and the vehicle-mounted terminal.

FIG. 35 is a block diagram showing a navigation system according to the sixth embodiment of the present invention.

In the figure, 50 is a navigation system, 61 is an in-vehicle terminal constituted by the navigation device 14 (FIG. 2), 51 is an information base, 52 is an information network connecting the information base 51 and the in-vehicle terminal 61,
Reference numeral 53 denotes a server arranged in the information base 51, which can transmit and receive various programs and data between the information base 51 and the vehicle-mounted terminal 61.
Therefore, the communication unit 38 of the vehicle-mounted terminal 61 includes a transmitter / receiver (not shown). Further, the server 53 includes a CPU 54 as a calculation device, a RAM 55, a ROM 56,
A computer is provided with a communication interface (not shown). In addition, the server 53 and the vehicle-mounted terminal 61
The navigation processing unit 17 may constitute a computer, and the computer may further include another arithmetic unit.

When the information base 51 is an information center, a navigation server is provided as the server 53 in the information center, and the information center and the vehicle-mounted terminal 61 are connected via the communication network as the information network 52. Connected and the information base 51 is a provider,
An internet server is provided as the server 53 in the provider, the provider and the vehicle-mounted terminal 61 are connected via the internet network as the server 53, and when the information base 51 is a base station, the base station is connected to the base station. Is provided, and the base station and the vehicle-mounted terminal 61 are connected to each other via the FM multiplex broadcasting network as the server 53, a telephone line network, or the like.

The server 53 is a map data file,
A recording device 57 is provided as an information recording unit for recording a database including a road data file, an intersection data file, a node data file, a search data file, a guidance data file, a facility data file and the like as navigation information. Data is recorded.

When various programs, data and the like are received by the communication unit 38 in the vehicle-mounted terminal 61, the CPU 31 of the navigation processing unit 17
The program is downloaded to the RAM 32, flash memory, hard disk, etc., the program is started, and various processes are performed based on the data. The program and the data may be recorded in different recording media, or may be recorded in the same recording medium.

Further, using a home-use personal computer, the program, data, etc. transmitted from the information base 51 are
It is also possible to download the program to an external recording medium such as a memory card or a flexible disk that is detachable from a personal computer, activate the program, and perform various processes based on the data.

By the way, since the server 53 can manage various data, the server 53 is not provided with the information acquisition processing means 92, the route search processing means 94 and the alternative route calculation processing means 95, but the server 53. CPU 5
4, the information acquisition processing means, the route search processing means and the alternative route calculation processing means are provided, and based on the present location, the departure place, the destination, etc. received from the vehicle-mounted terminal 61 and the search data read from the recording device 57, Search the route and search route F
It is also possible to send the search route F1, the alternative route, etc. to the vehicle-mounted terminal 61 while searching for the first alternative route, etc.

In each of the above-described embodiments, when searching for a route, the search is performed from the starting point side to the destination side and from the destination side to the starting point side. When searching a route based on search data having a layered structure composed of a plurality of layers, which is hierarchized according to the degree of detail up to the upper road, the search from the departure side and the search from the destination side are performed. The route search process and the alternative route calculation process may be ended in the layer to be performed.

In this case, in each layer, if the search branch is extended within the range determined by the predetermined condition, and the search branch from the departure side and the search branch from the destination side collide, The total value of the cost from the departure side and the cost from the destination side is added, and the route having the minimum total value is set as the search route. Then, if the branch of the search from the side of the starting point and the branch of the search from the side of the destination do not collide with each other, the layer moves to an upper layer under a predetermined condition and the branch of the search is extended.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0139]

As described in detail above, according to the present invention, each link cost is not weighted so as to simply avoid a search route. Therefore, for example, since an alternative route that becomes a detour is not calculated,
An alternative route that the driver wants can be calculated.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a navigation system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a main part of the navigation system according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a sample network according to the first embodiment of the present invention.

FIG. 4 is a first diagram illustrating costing in the first embodiment of the present invention.

FIG. 5 is a first diagram illustrating a search state according to the first embodiment of this invention.

FIG. 6 is a second diagram illustrating a search state according to the first embodiment of this invention.

FIG. 7 is a second diagram illustrating costing in the first embodiment of the present invention.

FIG. 8 is a third diagram illustrating a search state according to the first embodiment of this invention.

FIG. 9 is a fourth diagram illustrating a search state according to the first embodiment of this invention.

FIG. 10 is a third diagram illustrating costing in the first embodiment of the present invention.

FIG. 11 is a fifth diagram illustrating a search state according to the first embodiment of this invention.

FIG. 12 is a sixth diagram illustrating a search state according to the first embodiment of the present invention.

FIG. 13 is a fourth diagram illustrating costing in the first embodiment of the present invention.

FIG. 14 is a seventh diagram illustrating a search state according to the first embodiment of the present invention.

FIG. 15 is a diagram showing a search result from the starting point side in the first embodiment of the present invention.

FIG. 16 is a diagram for explaining costing from the departure place side in the first embodiment of the present invention.

FIG. 17 is a diagram showing a search result from the destination side according to the first embodiment of the present invention.

FIG. 18 is a diagram illustrating costing from the destination side in the first embodiment of the present invention.

FIG. 19 is a diagram showing a search route in the first embodiment of the present invention.

FIG. 20 is a flowchart showing an operation of an alternative route calculation process according to the first embodiment of the present invention.

FIG. 21 is a diagram showing a subroutine of cost calculation processing in the first embodiment of the present invention.

FIG. 22 is a first diagram showing a calculation example of a cost calculation process according to the first embodiment of the present invention.

FIG. 23 is a second diagram illustrating a calculation example of the cost calculation process according to the first embodiment of the present invention.

FIG. 24 is a diagram showing a calculation example of a cost calculation process according to the second embodiment of the present invention.

FIG. 25 is a diagram showing a calculation example of a cost calculation process according to the third embodiment of the present invention.

FIG. 26 is a flowchart showing an operation of an alternative route calculation process according to the fourth embodiment of the present invention.

FIG. 27 is a diagram showing a subroutine of departure point side cost reset processing in the fourth embodiment of the present invention.

FIG. 28 is a diagram illustrating costing from the starting point side in the fourth embodiment of the present invention.

FIG. 29 is a diagram showing a sample network according to the fourth embodiment of the present invention.

FIG. 30 is a diagram showing a search result from the departure place side according to the fourth embodiment of the present invention.

FIG. 31 is a diagram showing a search result from the destination side according to the fourth embodiment of the present invention.

FIG. 32 is a diagram showing a calculation example of a cost calculation process according to the fourth embodiment of the present invention.

FIG. 33 is a first diagram showing a subroutine of a departure place side cost reset process in the fifth embodiment of the invention.

FIG. 34 is a second diagram showing the subroutine of the starting point side cost reset processing in the fifth embodiment of the present invention.

FIG. 35 is a block diagram showing a navigation system according to a sixth embodiment of the present invention.

[Explanation of symbols]

17 Navigation processing unit 50 navigation system 53 servers 57 recorder 91 Information recording section 92 Information acquisition processing means 93 Destination setting processing means 94 Route Search Processing Means 95 Alternative route calculation processing means

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C032 HB02 HB22 HB24 HB25 HC08                       HC15 HC16 HC31 HD16 HD23                 2F029 AA02 AB01 AB07 AB13 AC02                       AC04 AC08 AC14 AC18                 5H180 AA01 BB02 BB04 BB12 BB13                       FF04 FF05 FF12 FF22 FF25                       FF27 FF33

Claims (9)

[Claims] 1. An information recording unit that records navigation information, an information acquisition processing unit that acquires the navigation information from the information recording unit, a destination setting processing unit that sets a destination, and the navigation information. On the basis of the link cost set for each link, based on the route search processing means for searching the route from the origin to the destination to obtain the search route, and the search result information indicating the search result by the route search processing means. , And an alternative route calculation processing means for calculating an alternative route. 2. The alternative route calculation processing means determines whether a predetermined link among the links of the alternative route overlaps with the link of the search route, and when they overlap, weights the link cost. The navigation system according to claim 1, wherein the alternative route is calculated by calculating the alternative route. 3. The alternative route calculation processing means, a cost calculation processing means for calculating an alternative route candidate cost for each candidate route calculated based on the search result information, and an alternative route candidate cost of the candidate routes. The navigation system according to claim 1, further comprising: an alternative route determination processing unit that determines the smallest route as the alternative route. 4. The cost calculation processing means weights the link cost based on the additional magnification when a predetermined link among the links of the candidate route overlaps with the link of the search route. The described navigation system. 5. The alternative route calculation processing means resets the link cost based on the direction information of the search result information, and the alternative route based on the reset link cost. The navigation system according to claim 1, further comprising a re-search processing unit that searches for. 6. The navigation system according to claim 5, wherein the cost resetting processing unit weights the link cost based on the additional magnification when the predetermined link overlaps with the link of the searched route. 7. The navigation system according to claim 4, wherein the additional magnification is changed based on a cumulative overlap rate due to overlapping links. 8. The navigation system according to claim 4, wherein the additional magnification is changed based on road traveling property. 9. A computer based on information acquisition processing means for acquiring navigation information from an information recording section, destination setting processing means for setting a destination, and link cost set for each link of the navigation information. ,
As a route search processing unit that searches for a route from a starting point to a destination to obtain a searched route, and an alternative route calculation processing unit that calculates an alternative route based on search result information indicating a search result by the route search processing unit. A program for a route search method to function.