JP3092406B2 - Route guidance device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle route guidance apparatus for searching for an optimal route to a destination and guiding occupants.

[0002]

2. Description of the Related Art When a destination is set, an optimal route from the current location to the destination is searched for, and the optimal route and the current location of the vehicle are displayed on a road map to guide an occupant to the destination. Route guidance devices are known. The search for the optimum route to this destination is performed by searching the vast intersection network data to find the infinite number of routes to the destination, such as the route with the shortest route or the route with the shortest travel time. The route is selected.

However, in the conventional vehicle route guidance device, since the occupant starts searching for the optimal route after setting the destination, the route guidance is not performed until the search is completed, and the occupant waits. There's a problem.

In order to solve this problem, Japanese Patent Laid-Open Publication No.
The search algorithm is improved as disclosed in JP-A-84998, the area to be searched is limited as disclosed in JP-A-2-306400, and the search algorithm is disclosed in JP-A-2-56591. As described above, proposals have been made to shorten the search time by making the intersection network data into a hierarchical structure, but still, it takes several minutes to search for the optimum route.

[0005] It is an object of the present invention to provide a vehicle route guidance device that promptly searches for an optimal route after setting a destination and starts guidance of an occupant.

[0006]

Means for Solving the Problems The present invention will be described with reference to FIG. 1 which is a claim correspondence diagram. The invention of claim 1 is a storage means 200 for storing road map data, and a setting for setting a destination. Means 201 and display means 202 for reading and displaying a road map from the storage means 200 and displaying the optimum route to the destination set by the setting means 201 and the current position of the vehicle on the road map, The present invention is applied to a vehicle route guidance device that guides a passenger to a destination. Then, the stop detection means 203 for detecting a stopping vehicle condition of the vehicle, from the stop <br/> vehicle state of the vehicle by the stop detection unit 203 is detected, searches the road map data storage means 200 are here When the destination is set by the first route searching means 204 and the setting means 201 for searching for the optimum route to each of the surrounding intersections, the search result by the first route searching means 204 and the road map of the storage means 200 A second route search unit 205 that searches for data and searches for an optimal route from the destination to the current location, thereby achieving the above object. In the vehicle route guidance device according to the second aspect, the stop detection means 203 is provided with an ignition key switch.
Power supply means 206 for detecting the stop state of the vehicle when the switch is turned off and continuing to supply power to the vehicle route guidance device for a preset time after the ignition is turned off , and an auxiliary power supply even after the power supply is stopped. A search result storage unit 208 that receives power supply from the power supply unit 207 and retains stored contents, and the first route search unit 204A selects an optimal route while power is supplied by the power supply unit 206 after the ignition is turned off , And the search result is stored in the search result storage means 208. According to the vehicle route guidance device of the third aspect, the vehicle stop detecting means 203
Means for detecting the vehicle speed of the vehicle.
Is detected . First route search means 204 B of the vehicular navigation system according to claim 4 is obtained by the current position so as to search for a route minimum journey to each intersection. The first route search means 204C of the vehicle route guidance device according to the fifth aspect is configured such that a minimum distance from the current position to each intersection is determined.
The route for the required travel time is searched.
The second route search means 2 of the vehicle route guidance device according to claim 6.
05 A performs a route search toward the current position from the destination, search and journey from the destination to any of the intersection, the intersection in the order sum is small and guess journey from the intersection to your location, search for the optimum route It is something to do. The second route searching means 20 of the vehicle route guidance device according to claim 7.
5 B performs a route search toward the current position from the destination,
The required travel time from the destination to any intersection
The sum of the estimated travel time from the difference to the current location is small.
An intersection is searched in order, and an optimum route is searched . Second route search means 205 D of the vehicle navigation system of claim 8, in which the search intersection was made to end the route search reaches the starting intersection <br/> difference point location neighborhood. The second route searcher of the vehicle route guidance device according to claim 9.
Step 205D is a step in which the search intersection is the first route search means 204
We reach the intersection where the route search has been completed by ~ 204C
Then, the route search is terminated.

[0007]

In the vehicle route guidance apparatus according to the first aspect, when the vehicle is in a stopped state, the road map data is searched to find an optimal route from the current location to each of the surrounding intersections. When the location is set, the search result of the route around the current location and the road map data are searched to find the optimal route from the destination to the current location. As a result, in the route search from the destination to the current location after the destination is set, it is not necessary to perform another route search to the intersection around the current location where the optimal route has already been searched, and the entire route is accordingly reduced. The search time is reduced, and the optimum route can be promptly displayed on the road map and the guidance of the occupant can be started. In the vehicle route guidance device according to the second aspect, the vehicle may be turned off by turning an ignition key switch.
Both stop states are detected, an optimal route from the current position to each of the surrounding intersections is searched for while the power is supplied after the ignition is turned off, and the search result is used as the auxiliary power supply 207 even after the supply of power is stopped. Is stored in the search result storage means 208 driven by. As a result, even if the power supply is stopped, the route search result around the current location is retained, and even if the destination is set immediately after the ignition is turned on, the search result around the current location is read out from the search result storage unit 208 and read. The optimum route from the destination to the current location can be calculated quickly. The route guidance device for a vehicle according to claim 3.
Detects the stopped state of the vehicle by the vehicle speed detecting means,
Search map data and go from current location to each intersection around it
After searching for the best route to reach and setting a destination,
Search the surrounding route search results and road map data to find the purpose
Search for the optimal route from the ground to the current location. This allows
In addition to the effect of the above claim 1, the destination is determined during the operation of the vehicle.
Stops detected when the vehicle stops even if they have been set or changed.
From the destination to the current location using the route search results around the car position
Calculate the optimal route up to quickly and start crew guidance
Wear.

[0008]

【Example】

-First Embodiment- FIGS. 2 and 3 are block diagrams showing the configuration of the first embodiment. As shown in the figure, the vehicle route guidance device 100 is mainly configured by a microcomputer including a CPU 1 and its peripheral components. The CPU 1 exchanges data with various devices via the system bus 2, executes a control program described later, calculates the current location of the vehicle, and searches for an optimal route from the current location to the destination. The azimuth sensor 3 is a sensor that detects the traveling azimuth of the vehicle.
It is connected to the system bus 2 via the / D converter 5 and the I / O controller 6. The vehicle speed sensor 7 is attached to, for example, a transmission, and generates a predetermined number of pulse signals per rotation of a speedometer pinion. The vehicle speed sensor 7 is connected to the system bus 2 via the I / O controller 6. The CPU 1 detects the traveling speed of the vehicle by detecting the number of pulses or the pulse period per unit time output from the vehicle speed sensor 7, and detects the traveling distance of the vehicle by counting the number of pulses. The key 8 is an operation member for inputting various commands and data such as a destination to the apparatus.
It is connected to the system bus 2 via the I / O controller 9. The audio output speaker 10 is connected to the system bus 2 via the sound generator 11 and the I / O controller 9. The GPS receiver 12 receives a GPS signal transmitted from a satellite, performs a GPS positioning operation, and detects the current position and the traveling direction of the vehicle.

In FIG. 3, a CD-ROM 16 is a storage device for storing road map data including intersection network data, and is connected to the system bus 2 via an interface SCSI controller 17. C
The RT 18 is a display functioning as a VDT (Visual Display Terminal), and is connected to the system bus 2 via the graphic controller 19. This CR
At T18, a road map around the current position of the vehicle is displayed, and an optimum route to the current position and the destination of the vehicle is displayed on the road map. The system bus 2 has a CRT 1
8, a V-RAM 20 for storing an image, a ROM 21 for storing a control program and the like to be described later, a D-RAM 22 for storing a route search result from the destination to the current location,
3. The S-RAM 24 for storing the current location and the route search results around the current location when the ignition is turned off is connected.

FIG. 4 shows the route guidance device 10 shown in FIGS.
0 is a power supply system diagram. Power is supplied to the route guidance device 100 of the first embodiment from a battery 101 via a key switch 102. The key switch 102
Ignition key not shown is ACC, ON, STAR
The circuit is closed when in any position of T, and is open when in the OFF position. Therefore, unless the ignition key is set to the OFF position, the route guidance device 100
Is supplied with power from the battery 101. The S-RAM 24 has two power supply systems. Normally, power is supplied from the battery 101 similarly to devices such as the CPU 1, the ROM 21 and the D-ROM 22, but even if the supply of the normal power is stopped. Power is supplied from the auxiliary battery 27, and the stored contents are retained. The auxiliary battery 27 is connected to the battery 101 and is always chargeable.

The timer 26 closes its contact when power is supplied to the route guidance device 100 by the key switch 102, and holds the contact closed for a preset time when the supply of power is stopped. Later, it opens. Therefore, even if the ignition key is set to the OFF position and the key switch 102 is turned off, the battery 101 is supplied to the route guidance apparatus 100 via the timer 26 for the set time.
Keeps supplying power. When the set time has elapsed, the timer 26 opens, and the supply of power to the route guidance device 100 is stopped. The timer 26 is set to a time sufficient to search for a route around the current location after the vehicle stops. That is, even if the occupant stops the vehicle and turns the ignition key to the OFF position, power is continuously supplied to the route guidance device 100 for the set time of the timer 26, and
U1 can search for the current location and the optimal route to each intersection around the current location.

FIG. 5 is a diagram for explaining a method of searching for an optimum route according to the first embodiment. In the first embodiment, while the battery power is being supplied by the timer 26 after the ignition is turned off, the current position of the vehicle is calculated,
Among a plurality of routes from the current position to an arbitrary intersection, a route with the smallest distance h to the intersection is searched for. A method for searching for an optimum route around the present location is disclosed in Japanese Patent Application Laid-Open No. 62-86499.
This is the same as the method disclosed in Japanese Patent Application Laid-Open Publication No. H10-210, but its outline will be described. A road map database including intersection network data and a memory for storing search results are prepared. In the storage memory of this search result, for each intersection,
The route h from the departure intersection and the intersection A immediately before each intersection on the optimal route from the departure intersection to each intersection are stored. The departure intersection is an intersection that satisfies a predetermined condition among the intersections near the current location as a departure intersection. In the following, the intersection searched for performing the route calculation is called a center intersection, and the intersection adjacent to the center intersection is called an adjacent intersection.

First, 0 is set for the route h at the departure intersection,
A constant equivalent to infinity is set for the route h of another intersection, and the departure intersection is set as the center intersection, and the route search is started. The distance h0 from the departure intersection stored in the distance of the center intersection and the distance h from the center intersection to the adjacent intersection are added, and the distance h from the departure intersection to the adjacent intersection is added.
1 is obtained and compared with the distance h2 from the departure intersection already stored in the distance of the adjacent intersection. If the distance h1 calculated this time is smaller than h2, the distance h2 of the adjacent intersection is changed to h1, and a center intersection is set at the intersection A immediately before the adjacent intersection. When the above processing is completed for all the adjacent intersections adjacent to the center intersection, the intersection having the minimum distance h from the departure intersection among all the intersections except the intersection already selected as the center intersection is set to the next new center. Set at the intersection. Less than,
The above-described processing is performed on the intersection adjacent to the new center intersection. In this way, a new center intersection is set in ascending order from the departure intersection, and the route search is performed. At the intersection where the route search has been completed, if the vehicle sequentially follows the intersection A immediately before the intersection, it reaches the departure intersection. The route is the optimal route of the minimum distance from the departure intersection to the intersection.

After the ignition is turned on, when the destination of the vehicle is set, an optimal route from the destination to the current location is searched. Here, the optimal route from the destination to the current location is the route with the smallest route. In the search for the optimum route from the destination to the current location, an intersection that satisfies a predetermined condition is specified from the intersections near the destination as the destination intersection, and the search is started from the intersection around the destination intersection. In addition, the search result storage memory stores, for each intersection, a route g from the destination intersection, an intersection B immediately before each intersection on the optimal route from the destination intersection to each intersection, and a route from each intersection to the departure intersection. The guessed route h 'is stored. In the first embodiment, the straight-line distance from each intersection to the current location is calculated based on the road map data, and is set as an estimated travel distance h ′.

First, 0 is set for the route g of the destination intersection,
A constant equivalent to infinity is set for the distance g of the other intersection, and a route search from the destination is started with the target intersection set as the center intersection. The process g0 from the target intersection to the adjacent intersection is obtained by adding the process g0 from the target intersection stored in the process of the central intersection to the process from the central intersection to the adjacent intersection, and is already stored in the process of the adjacent intersection. Is compared with the travel distance g2 from the destination intersection.
If the distance g1 calculated this time is smaller than g2, the distance g2 of the adjacent intersection is changed to g1, and a center intersection is set at the intersection B immediately before the adjacent intersection.
Further, an estimated travel distance h ′ from the adjacent intersection to the departure intersection is calculated and stored. When the above processing is completed for all the adjacent intersections adjacent to the central intersection, the route g from the destination intersection and the estimated route h 'to the departure intersection are selected from all the intersections except the intersection already selected as the central intersection. The intersection with the smallest sum (g + h ′) is set as the next new central intersection. Hereinafter, the above-described processing is performed on the intersection adjacent to the new center intersection.

In this way, a new center intersection is set in ascending order of the sum (g + h ') of the distance g from the destination intersection and the estimated distance h' to the departure intersection, and a route search from the destination is performed. During the search, if the adjacent intersection arrives at the intersection where the above-described route search from the vicinity of the current location has been completed, that is, at the intersection where the optimal route of the route h from the departure intersection is being searched, the target of the adjacent intersection is The sum of the distance g from the intersection and the distance h from the departure intersection (g +
h), that is, the route (g + h) from the departure intersection to the destination intersection of the route passing through the adjacent intersection is obtained, and is compared with g3 stored in the departure intersection route. Here, the journey g of the departure intersection is a journey from the departure intersection to the destination intersection. As a result of the comparison, the distance (g +
If h) is smaller than g3, the distance g3 of the departure intersection
Is changed to (g + h), and the adjacent intersection is set at the intersection B immediately before the departure intersection. Here, the intersection B immediately before the departure intersection is an intersection in the area 1 which reaches first during the route search from the destination, as shown in FIG.
In the following, such an intersection is referred to as a contact intersection because it is an intersection at a point where the region 1 and the region 2 meet.

When a route search from a destination is performed by this method, as shown in FIG. 5, the search area 2 becomes narrower as it approaches the current location. When the center intersection is set in ascending order of the route (g + h ') and the route search from the destination is advanced, the departure intersection finally becomes the center intersection. At that point, the route search from the destination ends. Finally, the route passing through the junction intersection stored at the intersection B immediately before the departure intersection is the optimal route of the minimum route from the destination intersection to the departure intersection, and the route of the route is the final route g of the departure intersection. Indicated by

Comparing the route search from around the current position with the route search from around the destination, the former is an omnidirectional route search, while the latter is a directional route search. The former searches for intersections in ascending order of the distance h from the departure intersection to each intersection, while the latter searches for the journey g from the destination intersection to each intersection and the estimated route h 'from those intersections to the departure intersection. Sum (g +
The intersections are searched in ascending order of h ′). Therefore, comparing the time required for both route searches under the same conditions, the latter, which performs a directional route search, requires a small amount of calculation, so that the search can be performed in about 1/5 of the former case. it can. Therefore, while the battery power is supplied after the ignition is turned off, a non-directional route search around the current location is performed as much as possible, and the search result is stored in the S-RAM 24. When the destination is set after the ignition is turned on, a route search result around the current location is read from the S-RAM 24, and a directional route search is performed from the destination to the current location. Then, when the latter route search reaches the former searched area 1, the optimal route from the current position to the destination is selected using the former search result. As shown in FIG. 5, since the optimum route has already been searched for the intersection of the area 2B in the latter search area 2,
The calculation time for the area 2B is not required, and the entire route search time can be shortened accordingly. When the route search area 1 around the current location is wide and the destination is set in the former search area 1, the route search from the current location to the destination is almost instantaneously completed.

FIG. 6 is a flowchart showing a main control program executed by the CPU 1, FIGS. 7 and 8 are flowcharts showing an optimal route search program to each intersection around the current location, and FIGS. It is a flowchart which shows a route search program. FIG. 12 is an intersection network diagram for explaining a method of searching for an optimum route. The operation of the first embodiment will be described with reference to these drawings. When the ignition switch 102 is turned on and the power is supplied to the route guidance device 100, the CP
U1 starts executing the IGN ON program shown in FIG. At step S1 after the start of the execution, it is determined whether or not the destination is set by the key 8, and if the destination is set, the process proceeds to step S2. If the destination is not set, the execution of the program is terminated.

When the destination is set, the S-RAM 24
The search data of the optimum route from the to the respective intersections around the current position is read. The search data is calculated while the vehicle is stopped and the ignition key 102 is turned off and the timer 26 continues to supply the battery power to the route guidance apparatus 100. Subsequent step S
In step 3, the subroutine shown in FIGS.
Using the route search data around the current location read from the AM 24, an optimal route from the destination to the current location is searched. When the optimal route from the destination to the current location is selected, the process proceeds to step S4, where a road map around the current location is displayed on the CRT 18, and the optimal route to the current location and the destination of the vehicle is displayed on the road map. In addition, the road map is scrolled as the vehicle moves, and the current location is updated.

When the ignition switch 102 is turned off, the CPU 1 starts executing an IGN OFF program shown in FIG. Timer 26 in step S6
And proceeds to step S7 to read the current location of the vehicle from the D-RAM 22. The CPU 1 always calculates the current position of the vehicle when the ignition switch 102 is turned on. That is, the output pulse signal of the vehicle speed sensor 7 is counted to detect the traveling distance of the vehicle, and the traveling locus of the vehicle is calculated based on the detected traveling distance and the traveling direction of the vehicle detected by the direction sensor 3. Further, the current position of the vehicle is calculated by performing map matching based on the calculated traveling locus and the road map stored in the CD-ROM 16 and stored in the D-RAM 22. Therefore, when the ignition switch 102 is turned off, the D-RAM
The stop position of the vehicle, that is, the current location is stored in 22, and the stored position is read. At this time, if the accurate current position of the vehicle is detected by the GPS receiver 12, the current position is corrected using the current position obtained by the GPS positioning. Next, in step S8, the subroutine shown in FIGS. 7 and 8 is executed to start searching for an optimal route to each intersection around the current location, and the search result is stored in the S-RAM 24. In a succeeding step S9, when the timer 26 times out, the execution of the program is terminated, and the route guidance device 100
Stop supplying power to the

As described above, even if the ignition key is turned off, the power is continuously supplied to the route guidance apparatus 100 for a predetermined time, and the optimum route to each intersection around the current position is searched for. When the ignition key is turned on again and the destination is set, the optimal route from the destination to the current location is searched using the search result of the optimal route to each intersection around the current location, and the current location is searched for on the road map. The optimal route to the destination is displayed to guide the occupants.

FIGS. 13 to 16 are diagrams showing route search results stored in the S-RAM 24. FIG. (A) is a list A showing the optimum route information. In this list A, each intersection around the current location, the route h to those intersections, a flag indicating that it has been set at the central intersection, and each intersection around the current location are shown. The preceding intersection A on the route to be reached, the route g from the destination to each intersection around the destination, and the immediately preceding intersection B on the route from the destination to each intersection around the destination are included. (B)
Is a list B indicating the intersections of the central intersection candidates. For the intersection selected as the center intersection, the optimal route and the route h from the departure intersection are calculated.

With reference to these figures and the flowcharts shown in FIGS. 7 and 8, the search for the optimum route to each intersection around the current position will be described by taking the intersection network shown in FIG. 12 as an example. In step S100 of FIG. 7, the departure intersection is specified. This departure intersection is described in, for example, JP-A-62-86499.
As disclosed in the official gazette, from the intersection around the current location, there is outside the circle of a predetermined radius around the current location,
And the intersection closest to the current location is selected as the departure intersection. Now, it is assumed that the intersection 1 is selected as the departure intersection as shown in FIG. In FIG. 12, the intersection is represented by a circle, and the number in the circle indicates the intersection number. Furthermore, the lines connecting the intersections indicate the roads, and the numbers on each road indicate the distance from the intersection to the intersection. Next, step S102
Proceed to and make the departure intersection the central intersection. In the example of FIG. 12, the departure intersection 1 is the center intersection. Subsequent step S
At 104, various data of the list A in the S-RAM 24 are initialized. That is, as shown in FIG.
The flags of all the intersections are set to 0, the distance h of the departure intersection is set to 0, and the values h of all the other intersections are set to a very large value + ∞.

In step S106, one of the intersections adjacent to the central intersection is selected. Subsequent step S
At 108, the value obtained by adding the distance from the center intersection to the selected adjacent intersection to the distance h from the central intersection is compared with the distance h from the adjacent intersection. If the former is smaller, the process proceeds to step S110; Step S12 in FIG.
Go to 0. In step S110, the route h of the central intersection
Is added to the distance from the center intersection to the selected adjacent intersection to the value of the distance h of the adjacent intersection. Step S
The process of 106 to S110 will be described with reference to the example of FIG. 12. Intersections 2 to 5 are adjacent to the central intersection 1, and the intersection 2 is first selected from these adjacent intersections. Then, the route h = 0 at the central intersection 1 (see FIG. 13A)
Is compared with the value 3 obtained by adding the distance 3 from the central intersection 1 to the adjacent intersection 2 to the distance h = ∞ (see FIG. 13 (a)) of the adjacent intersection 2. Since the former is smaller, FIG. a)
As shown in (2), the distance h = ∞ of the adjacent intersection 2 is changed to the calculated value 3.

Proceeding to step S112 in FIG. 8, it is determined whether or not the currently selected adjacent intersection exists in the center intersection candidate list B. If not, step S116 is performed.
Then, if it exists, step S116 is skipped.
In step S116, the currently selected adjacent intersection is added to the center intersection candidate list B. Further, in step S118, the center intersection at this time is recorded as the intersection A immediately before the currently selected adjacent intersection. In the example of FIG. 12, since the currently selected adjacent intersection 2 does not yet exist in the center intersection candidate list B, the number of the adjacent intersection 2 is registered in the list B shown in FIG.
As the immediately preceding intersection A of the currently selected adjacent intersection 2, the intersection number of the central intersection 1 is recorded in the column of the immediately preceding intersection A of the list A shown in FIG.

In step S120, it is determined whether or not the above examination has been performed for all intersections adjacent to the central intersection. If the examination has been completed, the process proceeds to step S122; otherwise, the process proceeds to step S106 in FIG. Return and repeat the above process. FIGS. 13A and 13B show the contents stored in the S-RAM 24 at the time when the above-described processing is completed for the intersections 2 to 5 adjacent to the central intersection 1. In list A, the route h of each adjacent intersection 2 to 5 and the immediately preceding intersection 1 are set, and in list B, intersections 2 to 5 of the center intersection candidates are recorded.

In step S122, it is determined whether or not the center intersection candidate list B is empty. If the intersection of the center intersection candidate is not registered in the list B, the entire intersection of the road map stored in the CD-ROM 16 is determined. On the other hand, it is determined that the route search has been completed, and the execution of the program is terminated. Otherwise, the process proceeds to step S124. Normally, before the route search from the current location is completed for the entire range of the road map prepared in advance, a destination is set and a route search from the destination described later is started.

If the center intersection candidate list B is not empty, the intersection of the minimum distance h is determined as a new center intersection from the intersections registered in the list B in step S124, and the flow advances to step S126. Step S126
Then, the intersection newly selected as the center intersection is deleted from the list B, and the flag of the center intersection so far in the list A is set to 1 in the subsequent step S128. In the example of FIG. 12, adjacent intersections 2 to 2 registered in the list B of FIG.
5, the distance h of the adjacent intersection 2 is the smallest, the adjacent intersection 2 is determined as a new center intersection, the intersection 2 is deleted from the list B, and the flag of the center intersection 1 up to that point in the list A is Set 1. S in that state
FIG. 14 shows the contents stored in the RAM 24.

Next, returning to step S106 in FIG. 7, the above-described processing is performed on the newly selected center intersection. In the example of FIG. 12, the newly selected center intersection 2 is the only intersection adjacent to the intersection 1, and when the calculation in step S <b> 108 is performed, the distance 3 from the center intersection 2 to the adjacent intersection 1 becomes the distance 3 of the center intersection 2. Is larger than the route h = 0 of the adjacent intersection 1, so that step S108 is denied and the process proceeds to step S120 in FIG.
The process of 10 or less, that is, the change of the route h of the adjacent intersection 1 is not performed. Further, in this case, steps S122 to S
Proceeding to 128, the intersection 4 having the minimum distance h from the intersections 3 to 5 recorded in the list B shown in FIG. 14B is determined as the new center intersection, and the intersection 4 is deleted from the list B. At the same time, the flag of the central intersection 2 in the list A is set to 1.

Next, a route search for the newly selected center intersection 4 is performed, and the above-described search processing is performed for the intersections 1, 5, and 6 adjacent to the center intersection 4. FIG. 1 shows changes in the recorded contents of the S-RAM 24 in this process.
It is shown in FIG. For the adjacent intersection 1, the value 8 obtained by adding the distance 4 from the central intersection 4 to the adjacent intersection 1 to the distance 4 of the central intersection 4 is larger than the distance 0 of the adjacent intersection 1.
Do not change journey h. For the adjacent intersection 5,
From Intersection 4 to Intersection 5 on Route 4 of Intersection 4
Since the value 5 obtained by adding the distance 1 to the road 5 is smaller than the distance 6 of the adjacent intersection 5, the distance h of the adjacent intersection 5 is changed from 6 to 5. Since the adjacent intersection 5 already exists in the list B, the recording in the list B is not performed. Also,
The intersection A immediately before the adjacent intersection 5 is changed from the intersection 1 to the intersection 4. For the adjacent intersection 6, the value 9 obtained by adding the distance 5 from the center intersection 4 to the adjacent intersection 6 to the distance 4 of the central intersection 4 is smaller than the distance ∞ of the adjacent intersection 6.
The distance of the adjacent intersection 6 is changed from ∞ to 9. Further, since this adjacent intersection 6 does not exist in the list B, the list B
And the intersection 4 is set at the intersection A immediately before the adjacent intersection 6 in the list A.

Next, from the intersections 3, 5, and 6 recorded in the center intersection candidate list B, the intersection having the minimum distance h is determined as a new center intersection. At this time, since both the intersection 3 and the intersection 5 have the minimum travel distance 3, in this case, any one of the intersection 3 and the intersection 5 is used.
Is selected as the central intersection. As you continue your search,
The central intersection changes from intersection 1 → 2 → 4 → 3 → 5 → 6 → 7. FIG. 16 shows the contents stored in the S-RAM 24 at the time when the route search is completed with the intersection 7 as the central intersection.

It is assumed that the time set in the timer 26 has elapsed at the time when the route search is completed with the intersection 7 as the central intersection. When the occupant sets a destination after the ignition is turned on, the CPU 1 executes an optimal route search routine from the destination to the current position shown in FIGS. Until now, the search for the optimal route to each intersection around the current location expands the search range non-directionally around the current location because no destination is set. On the other hand, the search for the optimal route from the destination to the current position shown in FIGS. 9 to 11 starts the search from the intersection around the destination and proceeds with the directivity in the direction of the current position. The search is completed in a limited time in a limited time.

FIGS. 17 to 20 are diagrams showing route search results from the destination stored in the D-RAM 22. FIG. The result of the route search from the destination to the current location is stored in the D-RAM 22. 17A and 17B, (a) and (b) are the above-described optimal route list A and center intersection candidate list B, respectively. (C) is a list C showing the intersections of the center intersection candidates around the destination. These figures and FIGS.
11, a description will be given of an optimal route search from the destination to the current location, taking the intersection network shown in FIG. 12 as an example. In step S200 in FIG. 9, the target intersection is specified. This destination intersection is selected from the intersections around the destination outside the circle of a predetermined radius centered on the destination and closest to the destination as the destination intersection, for example, similarly to the departure intersection described above. I do.
In the example of FIG. 12, it is assumed that the intersection 10 has been selected as the target intersection. Next, the process proceeds to step S202, and it is determined whether the flag of the list A for the selected target intersection is 1 or not, that is, whether or not the intersection has already been searched for by the above-described route search from the current location. If the intersection has been searched, step S204
The process proceeds to step S206 otherwise.

If the selected target intersection is an intersection for which the route search has already been completed, step S204 is executed.
-An optimal route to the departure intersection is obtained by sequentially following the target intersection of the optimal route list A stored in the RAM 24 to the immediately preceding intersection A. In the example of FIG. 12, if the target intersection is the intersection 7 for which the route search has been completed, the intersection A immediately before the target intersection 7 is the intersection 5 as shown in FIG. The intersection A immediately before the intersection 4 is the departure intersection 1.
Therefore, the optimal route from the departure intersection 1 to the destination intersection 7 is the route from the destination intersection 7 to the intersection 5 → intersection 4 → departure intersection 1 obtained by following the immediately preceding intersection A.
Note that if the search of the entire range of the road map has been completed by the above-described route search from the current location, no matter which intersection is set as the target intersection, the optimum intersection A of the optimal route list A is followed by the immediately preceding intersection A in order. As a result, an optimal route from the departure intersection to the destination intersection can be obtained immediately.

Since the destination intersection is the intersection 10 for which the route search has not been completed, step S202 is denied, and the process proceeds to step S206. In step S206, the target intersection is set as the center intersection, and the process proceeds to step S208.
As shown in FIG. 17, 0 is set for the route g of the target intersection 10 in the list A stored in the D-RAM 22, and a very large value + ∞ is set for the route g of the other intersection. Here, the journey g is a journey from the destination intersection to an arbitrary intersection, and corresponds to the journey h from the above-mentioned departure intersection to an arbitrary intersection around the current location. Step S21
At 0, one of the intersections adjacent to the center intersection is selected, and the process proceeds to step S212, where the distance g of the center intersection is determined.
The value obtained by adding the distance from the central intersection to the selected adjacent intersection is compared with the distance g of the adjacent intersection. If the former is smaller, the process proceeds to step S214.
The process proceeds to step S234 of FIG. In step S214,
A value obtained by adding the distance from the center intersection to the selected adjacent intersection to the distance g from the central intersection is set as the distance g from the adjacent intersection. In a succeeding step S216, a center intersection is set at the intersection B immediately before the currently selected adjacent intersection.

The processing steps of steps S206 to S216 will be described with reference to the example of FIG. 12. Intersections 8, 9, 11, and 12 are adjacent to the central intersection 10, and the intersection 8 is first selected from these adjacent intersections. I do. Then, the value 4 obtained by adding the route 4 from the center intersection 10 to the selected adjacent intersection 8 to the process g = 0 at the central intersection 10 (see FIG. 17A), and the process g = ∞ (see FIG. 17 (a), and the former is smaller than that of FIG. 17 (a).
As shown in (5), the distance g of the adjacent intersection 8 is changed from ∞ to the added value 4, and the center intersection 10 is set at the intersection B immediately before the adjacent intersection 8.

In step S218, it is determined whether or not 1 is set to the flag of the list A of the currently selected adjacent intersection. The fact that the flag of the adjacent intersection is set to 1 indicates that the search for the route from the vicinity of the current position to this adjacent intersection has been completed, and the optimum route from the departure intersection to the adjacent intersection has been selected. . That is, this adjacent intersection is the above-mentioned intersection, and indicates that the route search from the destination at this point has reached the range where the route search from around the current location has been completed. If the flag of the currently selected adjacent intersection is set to 1, the process proceeds to step S222 in FIG. 10, and if the flag remains 0, the process proceeds to step S250 in FIG. In the example of FIG. 12, intersections 8, 9, 11, and
All 12 flags are 0, and the process proceeds to step S250.

If the adjacent intersection that is being searched for in the route search from the destination is not the contact intersection for which a route search has been performed from around the current location, the adjacent intersection that is currently selected in step S250 in FIG. It is determined whether or not it exists in the candidate list C. The list C is a list for registering an intersection that can be a central intersection in searching for an optimal route from a destination. If the adjacent intersection is not in the center intersection candidate list C, the process proceeds to step S252. If the adjacent intersection is already in the center intersection candidate list C, step S2 is performed.
Skip 52. In step S252, the adjacent intersection is additionally registered in the center intersection candidate list C, and the straight-line distance from the departure intersection to the adjacent intersection is calculated and recorded as the estimated route h '. Further, the distance g from the center intersection to the adjacent intersection is recorded. In the example of FIG.
Since none of the intersections 8, 9, 11, and 12 adjacent to the center intersection 10 initially exist in the center intersection candidate list C,
As shown in FIG. 17, these adjacent intersections 8, 9, 11,
12 is recorded in the center intersection candidate list C, and the straight-line distance from the departure intersection to each of the adjacent intersections 8, 9, 11, and 12 is calculated and recorded as the estimated route h '. In addition,
The guessed distance h 'is a straight line distance from the departure intersection to the intersection being searched, and is therefore shorter than the distance h from the departure intersection to the intersection being searched. Further, in the list C, the distance g from the central intersection 10 to each adjacent intersection is recorded.

Next, the process proceeds to step S234 in FIG. 11, and it is determined whether or not the examination has been completed for all the intersections adjacent to the central intersection. When the examination has been completed for all the adjacent intersections, the process proceeds to step S236. Step S236
In the center intersection candidate list C, the smallest (g +
The intersection having h ′) is selected as a new center intersection, and the intersection newly selected as the center intersection is deleted from the list C in step S238. In the example of FIG. 12, when the above processing is completed for the intersections 8, 9, 11, and 12 adjacent to the central intersection 10, the adjacent intersection 9 having the minimum (g + h ′) as shown in FIG. A new center intersection is selected and this intersection 9 is deleted from list C.

On the other hand, if the flag of the adjacent intersection currently searched for is set to 1 in step S218 in FIG. 9, that is, if the adjacent intersection being searched for in the route search from the destination is a route-searched contact point around the current location If it is an intersection, the process proceeds to step S222 in FIG. Since the currently selected adjacent intersection is the contact intersection, the optimum route of the minimum distance h from the departure intersection is searched for. In step S222, the sum (g) of the distance g and the distance h of this adjacent intersection is obtained.
It is determined whether or not (+ h) is smaller than the distance g of the departure intersection. If it is smaller, the process proceeds to step S224; otherwise, the process proceeds to step S234 in FIG. Step S224
Then, the route g at the departure intersection is changed to the sum (g + h) of the routes g and h at the adjacent intersection. As described above, the route g of the departure intersection indicates a route from the departure intersection to the destination intersection. In a succeeding step S226, an adjacent intersection currently being searched is set at the intersection B immediately before the departure intersection in the list A. There is another intersection between the departure intersection and the adjacent intersection currently being searched, but the adjacent intersection currently being searched is a junction intersection, and the optimal route from the departure intersection has been determined. Other existing intersections are omitted, and the adjacent intersection currently being searched is set as the intersection immediately before the departure intersection.

In the example shown in FIG. 12, the intersections 7, 8, 10, and 12 adjacent to the new center intersection 9 are compared with the steps S in FIG.
When steps 210 and S212 are executed, step S212 is negative except for the adjacent intersection 7. In the case of the adjacent intersection 7 of the center intersection 9, the process proceeds to step S214, and the route g of the list A of the adjacent intersection 7 is g = 2 of the center intersection 9 from ∞, and the adjacent intersection 7 from the center intersection 9 as shown in FIG. It is changed to the sum 6 with the journey 4 up to. In addition, the center intersection 9 is set as the intersection B immediately before the adjacent intersection 7. Further, since 1 is set in the flag of the adjacent intersection 7, the adjacent intersection 7 becomes a contact intersection, and the step S218 is affirmed, and the process proceeds to the step S222 in FIG. Then, the sum (g + h) of the distance g and the distance h at the adjacent intersection 7 is compared with the distance g at the departure intersection 1, and the former is smaller.
As shown in g, g of the departure intersection 1 is g of the adjacent intersection 7
= 6 and h = 10 are changed to the sum 16. Then, the adjacent intersection 7 is set at the intersection B immediately before the departure intersection 1.

In step S228, it is determined whether or not the departure intersection exists in the center intersection candidate list C. If the departure intersection already exists in the list C, step S230 is skipped; otherwise, step S230 is executed. In step S230, the departure intersection and its journey g and g + h 'are recorded in the list C. In the example of FIG.
As shown in (c), the departure intersection 1 and its journey g = 16 are recorded in the list C, and the journey h 'of the departure intersection is recorded.
Is 0, g + h ′ = 16 is recorded.

Thereafter, steps S234 to S23 in FIG.
8 to perform the above processing. In the example of FIG. 12, the smallest intersection g + h ′ 8 is selected as the next center intersection from the center intersection candidates of the list C shown in FIG. 18C, and the intersection 8 selected as the center intersection from the list C is Will be erased. In step S240, it is determined whether or not the newly selected center intersection is the departure intersection. If the new center intersection is the departure intersection, it is determined that the route search from the destination has been completed, and the process proceeds to step S242. If not, the flow returns to step S210 in FIG. 9, and the above processing for the new center intersection is continued. In the example of FIG. 12, the above processing is performed on the intersections 6, 9, and 10 adjacent to the new center intersection 8.

For the intersections 9 and 10 among the intersections 6, 9 and 10 adjacent to the central intersection 8, step S21 in FIG.
2 is denied and the course g is not changed. However, the distance g = ∞ at the adjacent intersection 6 is larger than the sum 6 of the distance g = 4 at the center intersection 8 and the distance 2 from the center intersection 8 to the adjacent intersection 6, as shown in FIG. , The distance g of the adjacent intersection 6 is changed from ∞ to 6, and the adjacent intersection 6
The center intersection 8 is set at the intersection B immediately before. further,
Since the flag of the list A of the adjacent intersection 6 is set to 1, the processing of steps S222 to S230 is executed. First, since the sum 15 of g = 6 of the adjacent intersection 6 and the distance h = 9 calculated in the route search around the current position is smaller than g = 16 of the departure intersection 1, as shown in FIG. G = 16 of the departure intersection is changed to 15, and the intersection B immediately before the currently set departure intersection 1 is changed to the adjacent intersection 6 being searched.

Here, the change of the distance g at the departure intersection and the immediately preceding intersection B means that an optimum route from the destination intersection to the departure intersection is newly found. In the example shown in FIG. 12, the journey g = 1 at the initially set departure intersection 1
6 and the previous intersection B = 7 are from the target intersection 10 to the intersection 7
To departure intersection 1 via the route and the path g of that route
Indicates that the route g has been changed to 15 and the immediately preceding intersection B has been changed to 6, indicating that the route g is smaller than the originally set route, that is, the more optimal route, that is, from the destination intersection 10. This means that a route to the departure intersection 1 via the intersection 6 has been found. FIG. 19 shows the storage state of the D-RAM 22 at this time.

In the example of FIG. 12, the intersection 12 is selected as a new center intersection in the search stage shown in FIG. Since this new center intersection 12 is not a departure intersection, the steps after step S210 in FIG. 9 are executed again, the intersection 13 of the center intersection candidate is registered in the list C as shown in FIG. g and the previous intersection B are set.

In step S240 of FIG. 11, when the newly selected center intersection becomes the departure intersection,
It is determined that the search for the optimal route from the destination intersection to the departure intersection has been completed, and the process proceeds to step S242. Step S2
At 42, the intersection B immediately before the departure intersection is set as a contact intersection existing at a position where the search area 1 from the current location and the search area 2A (the hatched portion in the area 2) from the destination shown in FIG. . In the example of FIG. 12, the intersection 6 set at the intersection B immediately before the departure intersection 1 is set as the contact intersection.

In step S244, the intersection A is traced from the junction intersection recorded in the list A to the immediately preceding intersection A, and an intersection sequence A from the junction intersection to the departure intersection is obtained. In the example of FIG. 12, as shown in the list A of FIG.
Is the intersection 4 immediately before, and the intersection A immediately before the intersection 4 is the departure intersection 1, so that the intersection row A is 6
→ 4 → 1 Further, in step S246, the list A
The intersection B is traced from the junction intersection immediately before to the target intersection, and the intersection B from the junction intersection to the target intersection is determined. In the example of FIG. 12, as shown in list A of FIG.
The intersection B immediately before the intersection 6 is 8, and the intersection B immediately before the intersection 8 is the target intersection 10, so that the intersection row B is 6 → 8 → 10. In step S248, the intersection sequence A and the intersection sequence B are combined to obtain a route from the departure intersection to the destination intersection. That is, this route is the optimal route from the current location to the destination. In the example of FIG. 12, a route of 1 → 4 → 6 → 8 → 10 can be obtained by combining the intersection rows A and B, and this route is the optimal route from the current position to the destination.

As described above, when the ignition key is turned off, the power is continuously supplied to the route guidance device for a predetermined time,
The road map data is searched to find the route of the minimum distance from the current position to each of the surrounding intersections, and is stored in the S-RAM. When the ignition key is turned on again and the destination is set, the route search is started from the destination to the current location, and the destination search is performed based on the route search result around the current location and the road map data stored in the S-RAM. Intersections are searched in ascending order of the sum of the distance from the ground to an arbitrary intersection and the straight-line distance from the intersection to the current location, and a route search from the destination to the current location is performed. When the search intersection reaches the departure intersection near the current location, the route search is terminated, and the route with the minimum distance from the destination to the current location is selected as the optimal route. As a result, in the route search from the current location to the destination after the destination is set, it is not necessary to perform a new route search to an intersection around the current location where the optimum route has already been searched, and the route search time is reduced accordingly. Is shortened.

Second Embodiment FIG. 21 is a diagram for explaining a method for searching for an optimum route according to a second embodiment. The second embodiment is different from the first embodiment in a method of searching for a route from a destination to a current position. In the first embodiment, when the destination is set, the route search is started from the destination to the current location, and the route g from the destination intersection to the center intersection and the estimated route h ′ from the center intersection to the departure intersection are determined. The intersection (g + h ') is sequentially searched for the smallest intersection,
When the central intersection reaches the departure intersection, end the route search,
The route with the smallest distance from the destination intersection to the departure intersection was selected as the optimal route. In the second embodiment, when a destination is set, a route search is started from the destination to the current location, and a route g from the destination intersection to the center intersection and an estimated route h ′ from the center intersection to the departure intersection are calculated. Sum (g
+ H ') is a process of sequentially searching for the intersection where the intersection is the smallest.
However, when the center intersection reaches the junction intersection, that is, the intersection where the optimum route from the departure intersection has already been searched in the route search around the current location, the route search is terminated. Compared to FIG. 5 showing the search method of the first embodiment, the search area 3 from the destination of the second embodiment
Is narrower than the search area 2A of the first embodiment, and the number of intersections to be searched is reduced by that amount, thereby shortening the search time. However, on the other hand, since all routes from the destination intersection to the departure intersection have not been searched, there is a possibility that an optimal route other than the finally selected route may exist.

The configuration and the power supply system of the second embodiment are the same as those of the first embodiment shown in FIGS. 2 to 4, and the main control program and the optimum route search program to each intersection around the current position are different. This is the same as the first embodiment shown in FIGS. 6 to 8, and a description thereof will be omitted. Furthermore, this second
In this embodiment, the intersection network shown in FIG. 12 will be described as an example.

FIGS. 22 and 23 are flowcharts showing an optimum route search program from the destination to the current location.
FIGS. 9 to 9 show the route search program of the first embodiment.
Steps that perform the same processing as in step 11 are denoted by the same step numbers, and differences will be mainly described. 24 to 26 are diagrams showing route search results from the destination stored in the D-RAM 22. Steps S200 to S216 and steps S250 to S238 as in the first embodiment.
Is performed, and the above processing is performed on the intersection adjacent to the center intersection. Then, the intersection having the smallest (g + h ′) is selected as the new center intersection. Step S301 in FIG.
, It is determined whether the flag of the newly selected center intersection is 1, that is, whether or not the selected center intersection is a contact intersection already searched for in a route search around the current location. Step S if the intersection has been searched
Go to 302; otherwise, step S21 in FIG.
Return to 0. In step S302, the newly selected center intersection is set as a contact intersection. Thereafter, as in the first embodiment, the intersections A and B immediately before the contact intersection are traced from the list A stored in the D-RAM 22, and the optimum route from the departure intersection to the destination intersection is determined.

The route search according to the second embodiment will be described using the intersection network shown in FIG. 12 as an example. 24 to 27
FIG. 4 is a diagram showing a route search result from a destination stored in the D-RAM 22. Now, after the ignition is turned off,
The program shown in Fig. 8 is executed, and the intersection 7 around the current location is
It is assumed that the optimal route up to the current position is searched, the destination is set after the ignition is turned on, and the route search from the destination to the current position is started. Assuming that the intersection 10 around the destination is set as the destination intersection as in the first embodiment, first the destination intersection 10 becomes the center intersection, and the adjacent intersections 8, 9, 11, and
12 is performed, and the D-RAM 22
The route search result shown in FIG. In this state, the intersection 9 having the minimum distance (g + h ′) = 12 is selected as the next center intersection from the center intersection candidates in the list C.

When the above search is performed for the intersections 7, 8, 10, and 12 adjacent to the newly selected center intersection 9, the route search result shown in FIG. 25 is obtained, and the intersection 8 becomes the next new center intersection. Selected. When the above search is performed for the intersections 6, 9, and 10 adjacent to the center intersection 8, FIG.
Is obtained, and the intersection 12 is selected as the next new central intersection. And this central intersection 1
When the above search is performed for the two adjacent intersections 9, 10, and 13, the route search result of FIG. 17 is obtained, and the intersection 7 is selected as the next new central intersection.

The flag of the intersection 7 newly selected as the center intersection is set to 1, and this intersection 7 is a contact intersection where an optimal route to the current location has already been searched by searching for a route from the current location. Therefore, FIG.
Step S301 is affirmed, and the route search from the destination ends at this time. Then, following the intersections A and B immediately before the intersection 7, the optimal route 1 → 4 → 5 → 7 → 9 → 1
0 is obtained. The route of this route is the route h =
The sum of 10 and the path g = 6 is 16. In the route search of the first embodiment performed under the same conditions, 1 → 4 → 6
Since the route of → 8 → 10 was obtained, the route search from the destination in the second embodiment was insufficient, and it could not be searched even though there was another optimal route. .
However, the route search area from the destination in the second embodiment is narrower than the search area in the first embodiment, and the number of search intersections is small, so that the search time is shortened accordingly.

In each of the embodiments described above, the route having the minimum travel distance is set as the optimum route, but the route having the shortest required travel time may be set as the optimum route. In this case, the required traveling time must be calculated based on the distance between the intersections and the traveling speed, but it is difficult to specify the actual traveling speed in advance, so the speed limit between the intersections is used instead of the traveling speed. The required travel time may be calculated using the above. Further, in this case, the estimated required travel time from the intersection being searched in the route search from the destination to the departure intersection is calculated from the straight-line distance from the intersection to the departure intersection and the maximum speed that can be considered during that time. This possible maximum speed is the highest possible travel speed in the possible route from the intersection being searched to the departure intersection. For example, 100 on the route
If there is a m / h highway, the maximum traveling speed is 100 m / h
And

In each of the above-described embodiments, when the ignition is turned off, the search result of the optimum route to each intersection around the current position is stored in the S-RAM 24. For example, only the intersection of flag 1 and its journey h and the previous intersection A are S-RA
By storing the data in the M24, the capacity of the S-RAM 24 may be reduced to reduce the cost.

Further, in each of the above-described embodiments, when the ignition key is turned off, the calculation of the current position and the search for the optimum route to each intersection around the current position are performed. However, the stop state of the vehicle is detected by the vehicle speed sensor. Each time the vehicle stops, the current location is calculated and the optimal route to each intersection around the current location is searched, and when the destination is set, the optimal route from the destination to the current location is searched using the route search results around the current location. You may make it. If you do this,
Even if the destination is set or changed during the operation of the vehicle, the optimal route from the destination to the current location is calculated quickly using the route search results around the stop position found when the vehicle stopped, and the crew is guided. Can start.

In the configuration of the above embodiment, the CD-RO
M16 is a road map storage means, key 8 is a setting means, C
The RT 18 is a display means, the ignition switch 102 is a stop detection means, the CPU 1 and the control program shown in FIGS. 7 and 8 are a first route search means, and the CPU 1 and FIGS.
The control programs 22 and 23 constitute the second route search means, the timer 26 constitutes the power supply means, the auxiliary battery 27 constitutes the auxiliary power supply, and the S-RAM 24 constitutes the search result storage means.

[0061]

According to the present invention as described above, according to the present invention, and searches for an optimum route to each intersection of the peripheral from the current location by searching the road map data when it is in stop vehicle state of the vehicle, When the destination is set, the route search result around the current location and the road map data are searched to find the optimal route from the destination to the current location. There is no need to perform a new route search to the intersection around the current location where the optimal route has already been searched, and the route search time is shortened accordingly, and the optimal route is quickly searched after setting the destination To start crew guidance. Further, according to the invention of claim 2, when the ignition key switch is turned off,
After the ignition is turned off, power is supplied to the route guidance device for a preset time even after the ignition is turned off, and during that time, an optimal route from the current location to each of the surrounding intersections is searched for, and the search result is supplied to the power source. Even after the supply is stopped, the search result is stored in the search result storage means driven by the auxiliary power supply. The optimal route from the destination to the current location can be quickly calculated by reading. Further, according to claim 3
According to Ming, the vehicle stop state is detected by the vehicle speed detection means
And search the road map data to find
Search for optimal route to intersection and set destination
And the route search results around the current location and the road map data
Search for the best route from your destination to your current location
Therefore, in addition to the effect of the above claim 1, the operation of the vehicle
Even if the destination is set or changed during the stop of the vehicle
Using the route search results around the searched stop location,
Quickly calculate the optimal route from the ground to the current location and
Guidance can be started.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims.

FIG. 2 is a block diagram showing the configuration of the first embodiment.

FIG. 3 is a block diagram showing the configuration of the first embodiment, following FIG. 2;

FIG. 4 is a power supply system diagram of the first embodiment.

FIG. 5 is a diagram illustrating a method for searching for an optimum route according to the first embodiment.

FIG. 6 is a flowchart showing a main control program of the microcomputer.

FIG. 7 is a flowchart showing an optimum route search program to reach each intersection around the current location.

FIG. 8 is a flowchart showing an optimum route search program following each of FIG. 7 to each intersection around the current location.

FIG. 9 is a flowchart showing an optimal route search program from a destination to a current location.

FIG. 10 is a flowchart showing an optimal route search program from the destination to the current location, following FIG. 9;

FIG. 11 is a flowchart showing an optimum route search program from the destination to the current location, following FIG. 10;

FIG. 12 is an intersection network diagram for explaining a method of searching for an optimum route.

FIG. 13 is a view showing a route search result from a current location stored in an S-RAM.

FIG. 14 is a diagram showing a route search result from a current location stored in an S-RAM.

FIG. 15 is a view showing a route search result from a current location stored in an S-RAM.

FIG. 16 is a view showing a route search result from a current location stored in an S-RAM.

FIG. 17 is a view showing a result of a route search from a destination stored in the D-RAM.

FIG. 18 is a diagram showing a route search result from a destination stored in the D-RAM.

FIG. 19 is a diagram showing a route search result from a destination stored in the D-RAM.

FIG. 20 is a diagram showing a route search result from a destination stored in the D-RAM.

FIG. 21 is a diagram illustrating a method for searching for an optimum route according to the second embodiment.

FIG. 22 is a flowchart illustrating an optimal route search program from a destination to a current location according to the second embodiment.

FIG. 23 is a flowchart following FIG. 22 showing an optimal route search program from the destination to the current location according to the second embodiment;

FIG. 24 is a diagram showing a route search result from a destination stored in the D-RAM according to the second embodiment.

FIG. 25 is a diagram showing a route search result from a destination stored in the D-RAM according to the second embodiment.

FIG. 26 is a diagram showing a route search result from a destination stored in the D-RAM according to the second embodiment.

FIG. 27 is a diagram showing a route search result from a destination stored in the D-RAM according to the second embodiment.

[Explanation of symbols]

Reference Signs List 1 CPU 2 system bus 3 direction sensor 4 amplifier 5 A / D converter 6, 9 I / O controller 7 vehicle speed sensor 8 key 10 speaker 11 sound generator 12 GPS receiver 13 extended I / O 14 receiver 15 antenna 16 CD-ROM 17 SCSI Controller 18 CRT 19 Graphic Controller 20 V-RAM 21 ROM 22 D-RAM 23 Kanji ROM 24 S-RAM 26 Timer 27 Auxiliary Battery 100 Vehicle Route Guidance Device 101 Battery 102 Key Switch 200 Road Map Storage Means 201 Setting Means 202 Display means 203 Stop detection means 204, 204A, 204B, 204C First route search means 205, 205A, 205B, 205C, 205D Second route search means 20 Power supply means 207 the auxiliary power source 208 search result storage means

Continuation of front page (56) References JP-A-5-215562 (JP, A) JP-A-4-280287 (JP, A) JP-A-4-29013 (JP, A) JP-A-3-219397 (JP) , A) JP-A-3-135719 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969

Claims (9)

(57) [Claims] 1. Road map storage means for storing road map data; setting means for setting a destination; reading and displaying a road map from the road map storage means; and display means for displaying the current position optimal route and the vehicle to the set destination, in the vehicle navigation system for guiding to the destination of the passenger, and stop detecting means for detecting a stop car status of the vehicle When stopping the car condition of the vehicle by the stop detection means is detected, a first route search that searches for an optimum route from the road map data retrieved by the current position of the road map storage unit to each intersection of the periphery thereof Means, when a destination is set by the setting means, a search result by the first route search means and road map data in the road map storage means are searched, and The vehicle navigation system, characterized in that it comprises a second route search means for searching an optimum route to the current location. 2. The vehicle route guidance device according to claim 1, wherein said vehicle stop detecting means is configured to turn off an ignition key switch.
A power supply means for detecting the stop state of the vehicle, and continuing to supply power to the vehicle route guidance device for a preset time after the ignition is turned off , and from an auxiliary power supply even after the power supply is stopped. A search result storage unit for receiving stored power and storing stored contents, wherein the first route search unit searches for an optimum route while power is supplied by the power supply unit after ignition is turned off. And a search result stored in said search result storage means. 3. The vehicle route guidance device according to claim 1 , wherein the stop detecting means detects a vehicle speed of the vehicle.
And detecting a stopped state of the vehicle. 4. The route guidance device for a vehicle according to claim 1, wherein the first route search means searches for a route with a minimum distance from a current position to each intersection. Vehicle route guidance device. 5. A vehicle navigation system according to any one of claims 1-3, wherein said first route search means, from the current position to each intersection
A route guidance device for a vehicle, which searches for a route with a minimum required travel time . The vehicle navigation system according to any one of the paragraphs 6. The method of claim 1 to 5, wherein the second route search means performs a route search toward the location from the destination, optionally from the destination and journey <br/> to the intersection searching intersection in the order sum is small and inferred journey from the intersection to the current position, the vehicle route guidance device characterized by searching an optimal path. 7. The vehicular navigation system according to any one of claims 1 to 5, wherein the second route search means, toward the location from the destination
Perform a route search and find the required distance from the destination to any intersection
Travel time and estimated required travel from the intersection to the current location
Search for intersections in ascending order of time to find the optimal route
A route guidance device for a vehicle, characterized by searching . 8. The vehicle navigation system according to any one of claims 1-7, wherein the second route search means searches intersection location near
A route guidance device for a vehicle, wherein the route search is terminated when the vehicle reaches a departure intersection. 9. The vehicle according to claim 1, wherein
In the dual-use route guidance device, The second route searching means may determine that the search intersection is the first route.
Reach the intersection where the route search has been completed by the route search means
The route search is terminated.
Guiding device.