JPH07243860A - Route guidance system for vehicle - Google Patents

Abstract

PURPOSE: reduce search time by searching for a secondary path from a tentative departing point to a destination by searching for with a lower directivity than a primary route search means and then switching a being displayed to the secondary route when a vehicle arrives at the tentative departing point. CONSTITUTION:A CPU 1 exchanges data with each kind of equipment and calculates the current location of a vehicle according to a control program. An azimuth sensor 3 detects the traveling azimuth of the vehicle and is connected to a system bus 2 via an A/D converter 5 and an I/O controller 6 and then a vehicle speed sensor 7 generates a pulse signal per rotation of a speed meter pinion and is connected to the system bus 2 via the I/O controller 6. Then, the CPU 1 searches for the primary path from the current location to the destination by performing a route search with a high directivity and sets a tentative departing point on a primary route. Further, route search with a low directivity is performed and the secondary route from the tentative departing point to the destination is searched, and the being displayed is switched from the primary route to the secondary route when the vehicle reaches the tentative point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle route guide device for searching an optimum route to a destination and guiding an occupant.

[0002]

[Prior art and its problems] When a destination is set, a vehicle that searches for an optimum route from the current position to the destination, displays the optimum route and the current position of the vehicle on a road map, and guides an occupant to the destination A route guidance device is known. The search for the optimum route to this destination is performed by searching a huge amount of intersection network data and selecting from among the numerous routes to the destination, for example, the route with the minimum journey or the route with the minimum required travel time. Since the route is selected, there is a problem that it takes a long time to search.

In order to solve this problem, the search algorithm is improved (see Japanese Patent Laid-Open No. 2-184998) or the area to be searched is limited (Japanese Patent Laid-Open No. 2-30).
No. 6400), a cross-section network data has a hierarchical structure (see Japanese Patent Laid-Open No. 2-56591), and other proposals have been made to shorten the search time, but it still takes several minutes to find the optimum route. is doing.

An object of the present invention is to shorten the route search time of a vehicle route guidance device.

[0005]

The invention of claim 1 will be described with reference to FIG. 1 and FIG. 2 showing an embodiment. The invention of claim 1 includes a map storage means 16 for storing a map and a destination. Destination setting means 8 for setting the current location, and current location detection means 1, 3, 7, 12, 14, 15 for detecting the current location of the vehicle,
A primary route searching means 1 for performing a highly directional route search to search for a primary route from a current location to a destination, and a temporary departure place for setting a temporary departure place on the primary route searched by the primary route searching means 1. It is read from the setting means 1, the secondary route searching means 1 for performing a route search having a lower directivity than the primary route searching means 1 to search for a secondary route from the temporary departure point to the destination, and the map storage means 16. Display means 18 for displaying the primary route on the road map and switching the route being displayed from the primary route to the secondary route when the vehicle reaches the temporary departure place,
This achieves the above object. The temporary departure point setting means 1 of the vehicle route guidance device according to claim 2 predicts the search time of the secondary route by the secondary route search means 1 and arrives at the time point when the secondary route search ends. The point is set as a temporary departure point. The provisional starting point setting means 1 of the vehicle route guiding apparatus according to claim 3 estimates the secondary route search time based on the linear distance from the current position to the destination and the number of intersections existing between the two points. It is a thing. The provisional starting point setting means 1 of the vehicle route guiding device according to the fourth aspect is configured to set a predetermined time as the predicted search time of the secondary route. When the invention of claim 5 is described in association with FIG. 8 for explaining the search ranges of the primary route and the secondary route of one embodiment, the primary route searching means of the vehicle route guidance device of claim 5 is from the current position. The search is started, and the intersections where the total value (g + k · h) of the distance g from the departure intersection around the current location and k times the straight line distance h to the destination intersection around the destination (where k> 0) are small The search is performed until the target intersection is reached. The invention of claim 6 will be described with reference to FIG. 17 for explaining the search ranges of the primary route and the secondary route of the modified example of the embodiment.
The primary route searching means for the vehicle route guiding device according to claim 6 is
The search starts from the destination, and the total value (g + kh) of the distance g from the destination intersection around the destination and the straight line distance h to the departure intersection around the current location is k times (where k> 0) The intersections are searched sequentially until the starting intersection is reached. The primary route searching means 1 of the vehicle route guiding apparatus according to the seventh aspect is adapted to set a value larger than the value of k at the time of secondary route searching.

[0006]

According to the vehicle route guiding apparatus of the first aspect, a route with high directivity is searched for a primary route from the current position to the destination, the primary route searched is displayed on the road map, and the primary route is displayed. A temporary departure place is set on the route, a route with a lower directivity than the primary route search is performed to search for a secondary route from the temporary departure place to the destination, and it is displayed when the vehicle reaches the temporary departure place. The route of is switched from the primary route to the secondary route. As a result, the search for the primary route is completed in a short time using a highly directional search method, and after the occupant has boarded the vehicle, the primary route is displayed immediately and the route guidance is provided without waiting for a long time for the route search. Be started. Also, since the secondary route is searched by a search method having a lower directivity than the primary route, the optimal route is searched, and the display route is switched from the primary route to the secondary route from the temporary departure point, and the optimal secondary route is obtained. Route guidance is performed along the route to the destination. In the vehicle route guidance device according to the second aspect, the search time for the secondary route is predicted, and a point on the primary route reached when the search for the secondary route ends is set as a temporary departure point. As a result, the guidance by the primary route is limited to the necessary minimum range, the guidance range by the optimal secondary route is widened, and proper route guidance is performed. In the vehicle route guidance device according to the third aspect, the search time of the secondary route is predicted based on the straight line distance from the current position to the destination and the number of intersections existing between the two points. Since the secondary route is a route from the temporary departure place to the destination, the route search time from the temporary departure place to the destination should be predicted,
Since the temporary departure point itself has not been determined, the search time for the route from the current location to the destination instead of the route from the temporary departure location to the destination is the linear distance from the current location to the destination and between the two points. Predict based on the number of intersections. In this way, the estimated search time will be longer by the search time from the current location to the temporary departure point, but the search time on the secondary route is so short that it can be ignored compared to the traveling time from the current location to the destination, so the temporary departure point is near the current location. It is possible that the search time of the secondary path can be reasonably predicted. In the vehicle route guiding device according to the fourth aspect, the predetermined time is set as the predicted search time of the secondary route. Since the secondary route search time in normal route guidance ends within 5 to 10 minutes, the search time can be predicted in a short time by setting the expected search time of the secondary route to a predetermined time longer than that. Even if the estimated search time is set to, for example, 15 minutes, this estimated time is sufficiently small as compared with the usual traveling time from the current position to the destination, so that there is no problem. In the vehicle route guidance device according to claim 5, when the primary route is searched, the search is started from the current position, and the distance g from the starting intersection around the current position and the straight line distance h to the target intersection around the destination are k times. Intersections with a small total value (g + k · h) are sequentially searched until the target intersection is reached. As a result, the route search is performed in a wide range around the current location, and the optimum route is searched. In other words, since the temporary departure point is close to the current location, the optimal primary route from the current location to the temporary departure location is searched, while the optimal secondary route from the temporary departure location to the destination is searched, so that the occupant can move to the vehicle. Route guidance is started immediately after boarding, and guidance is performed along the optimal route from the present location to the destination. In the vehicle route guidance device according to claim 6, when the primary route is searched, the search is started from the destination, and the distance g from the destination intersection around the destination and the straight line distance h to the departure intersection around the current location are k times. The intersections having a small total value (g + k · h) are sequentially searched, and the search is performed until the starting intersection is reached. As a result, a highly directional route search is performed, and an accurate route around the destination can be searched. In the vehicle route guiding apparatus according to the seventh aspect, the value of k during the primary route search is set to a value larger than the value during the secondary route search. As a result, the primary route search has a higher directivity than the secondary route search, the search is completed in a short time, and the waiting time of the occupant before the route guidance is started is shortened.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used in order to make the present invention easy to understand. It is not limited to.

[0008]

1 and 2 are block diagrams showing the configuration of a first embodiment. This vehicle route guidance device 100 is
As shown in the figure, it is mainly composed of a microcomputer composed of PU1 and its peripheral parts. The CPU 1 exchanges data with various devices via the system bus 2,
The control program to be described later is executed to calculate the current position of the vehicle and search for the optimum route from the current position to the destination. The direction sensor 3 is a sensor that detects the traveling direction of the vehicle, and is connected to the system bus 2 via the amplifier 4, the A / 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 one rotation of the speedometer pinion. The vehicle speed sensor 7 is connected to the system bus 2 via the I / O controller 6. CP
U1 detects the traveling speed of the vehicle by detecting the number of pulses per unit time or the pulse cycle output from the vehicle speed sensor 7, and also 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 device, and 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 GPS signals transmitted from satellites,
GPS positioning calculation is performed to detect the current position and traveling direction of the vehicle.

In FIG. 2, the 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 the interface SCSI controller 17. C
The RT 18 is a display that functions as a VDT (Visual Display Terminal), and is connected to the system bus 2 via the graphic controller 19. This CR
A road map around the current position of the vehicle is displayed at T18, and the 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 V-RAM 20 for image storage, ROM 21 for storing control programs described later, D-RAM 22 for storing the route search result from the destination to the current location, Kanji ROM 2
3. A non-volatile S-RAM 24 is connected. This S-
The RAM 24 is provided with two power supply systems, and while the main switch (not shown) of the route guiding device 100 is turned on, power is supplied from an in-vehicle battery (not shown) like the devices such as the CPU 1 and the main switch. Even if the battery is released and the power supply from the vehicle-mounted battery is stopped, power is supplied from the auxiliary battery (not shown) and the stored contents are retained. The auxiliary battery is connected to a vehicle-mounted battery and can be constantly charged.

3 to 7 and 9 to 10 are flowcharts showing the control program executed by the CPU 1. The operation of the embodiment will be described with reference to these flowcharts. FIG. 3 is a flowchart showing the main program. When the main switch of the key 8 of the route guiding apparatus 100 is turned on, the CPU 1 starts executing the control program shown in FIG. In step S110 after the start of execution, initialization processing such as setting of input / output conditions is performed, and in subsequent step S120, initial position information is input.
The initial position information includes the initial position information input by the passenger operating the key 8 and the traveling direction of the vehicle detected by the direction sensor 3. The current position and the heading of the vehicle detected by GPS positioning may be used as the initial position information. In step S130, the current position mark is displayed on the road map displayed on the CRT 18 according to the initial position and the traveling direction input in the above step.
Further, in step S140, the interrupt is enabled and the process proceeds to step S150, where the CP by the watchdog timer is set.
While performing a background job such as U1 runaway monitoring, it waits for occurrence of a current position calculation interrupt process, a route calculation process, and a destination setting process, which will be described later.

FIG. 4 is a flow chart showing a current position calculation interrupt processing routine. Each time the traveling distance detected based on the pulse signal from the vehicle speed sensor 7 reaches a predetermined value, the CPU 1 is interrupted by the present position calculation, and the CPU 1 executes this interrupt routine. Immediately after the execution is started, the interruption is prohibited in step S210, and then the process proceeds to step S220, in which the vehicle travel is detected based on the traveling distance detected based on the pulse signal from the vehicle speed sensor 7 and the traveling direction detected by the direction sensor 3. The running locus is obtained, and the current position and heading of the vehicle are calculated by map matching with the road map data. At this time, the current position and traveling direction detected by GPS positioning may be used. In step S230, it is determined whether or not the current position and traveling direction have changed from the previously detected position and direction. If they have changed, the process proceeds to step S240, and if they have not changed, the process proceeds to step S250. When the current position and the heading change, the current position mark is displayed again according to the newly detected current position and heading in step S240. Then, in step S250, the interrupt is permitted and the process returns.

FIG. 5 is a flowchart showing a destination setting processing routine. When the occupant sets the destination with the key 8, the CPU 1 executes this destination setting processing routine. In the route calculation processing routine described later,
If the destination is not set, the passenger is requested to set the destination. In step S310, interrupt is prohibited, and the process proceeds to step S320. After inputting the set destination, in step S330, interrupt is permitted and the process returns.

Here, the route search method from the present location to the destination in this embodiment will be described. When an occupant wants to leave for the destination immediately after boarding the vehicle,
Search for the "primary route" from the detected current location to the destination set by the occupant. The primary route is a route that can be searched in a short time because the occupant desires to start immediately, and is a route that can reach the destination for the time being, even if it is not optimal. However, it is desirable to search as accurately as possible in the vicinity of the departure point to find the optimum route. In this embodiment, the primary route is calculated by a search method with high directivity described later. Further, the optimum route from the current position to the destination includes a route with the smallest journey (hereinafter referred to as the shortest route), a route with the shortest required time, and the like. Let me give you an example.
After the primary route is calculated, the primary route is displayed on the CRT 18 to start guiding the occupant. As described above, since the primary route is calculated in a short time, the occupant does not have to wait for a long time for route search, and the CRT 18
You can depart to your destination along the primary route shown in.

On the other hand, the primary route is displayed and the occupant guidance is started, and at the same time, the "secondary route" is searched. This secondary route is the optimum route between the destination and the point on the way from the present location to the destination, that is, the shortest route, and it is accurate by performing a route search with a directivity lower than that of the primary route search. It is the route calculated in. By the way, the occupant is already traveling to the destination according to the guidance by the primary route, and it is necessary to switch the guidance route from the primary route to the optimum secondary route when the secondary route is calculated. This switching of the guide route may be performed at a point on the primary route that is reached when the search for the secondary route is completed. Hereinafter, this point will be referred to as a temporary departure point, and the secondary route will be the shortest route from the temporary departure point to the destination.

The temporary departure place is determined as follows.
First, the search time of the secondary route is predicted. The secondary route is the route from the temporary departure point to the destination, but since the temporary departure point has not been determined yet, the search time for the secondary route from the current location to the destination instead of the temporary departure point to the destination Anticipate.
In this case, the expected search time will be longer by the search time from the current location to the temporary departure point, but normally the secondary route search time is negligible compared to the travel time from the current location to the destination, so there is no problem. . In this embodiment, the expected search time of the secondary route is determined based on the linear distance between the two points of the current position and the destination, the number of intersections existing between the current position and the destination in the read road map data, and the like. To do. The expected search time of the secondary route is not limited to the above-described prediction method, and a predetermined time (for example, 15 minutes) may be set. Once the expected search time of the secondary route is calculated, calculate how far you can go with the above expected search time, assuming that you did not get caught in traffic congestion and kept on the regulated speed and smoothly traveled on the primary route,
The intersection passing after this arrival point is set as the temporary departure point. In other words, when the temporary departure point is reached, the secondary route, that is, the accurate shortest route to the destination has been searched, and the guidance route is switched from the primary route to the secondary route at the temporary departure point. The next route may be displayed on the CRT 18 to guide the passenger to the destination.

When the occupant does not wish to depart immediately after boarding the vehicle, it is determined that the occupant may be allowed to wait at least for the time for searching the secondary route, and from the beginning to the current position to the destination. The secondary route, that is, the shortest route is searched, and when the search is completed, the secondary route is displayed on the CRT 18 to start the guidance.

FIG. 6 is a flow chart showing a route calculation processing routine. When an occupant performs an operation for route calculation using the key 8, the CPU 1 starts executing this route calculation processing routine. Immediately after the execution is started, the interrupt is prohibited in step S410, and then the process proceeds to step S415 to determine whether or not the destination is set. When the destination has not been set, the process proceeds to step S420 to display a caution display prompting the passenger to set the destination on the CRT 18, and the destination set by executing the destination setting processing routine shown in FIG. Enter. If the destination has already been set, or if the destination has been set in step S420, it is determined in step S425 based on the setting information from the key 8 whether or not the occupant desires to immediately leave. , Step S if you want to start immediately
If not, the process proceeds to step S450.

When the occupant desires to depart immediately after boarding the vehicle, the above-described primary route calculation processing is performed in step S430 to search for a primary route between the present location and the destination. When the search for the primary route is completed, a route guidance processing routine, which will be described later, is executed in parallel in step S435, and the route guidance process is started in accordance with the searched primary route. As described above, the primary route is searched in a short time, so the passengers do not have to wait for a long time to search for the route, and should leave the destination along the primary route displayed on the CRT 18 shortly after boarding. You can Step S4
The search time of the secondary route is predicted by the method described above at 40, and the temporary departure point is calculated by the method described above at step S445.

In step S450, if the occupant desires to leave immediately after boarding, a secondary route from the temporary departure point to the destination is searched. On the other hand, after boarding,
If you do not wish to depart immediately, search for a secondary route from your original origin to your destination. When the search for the secondary route is completed, the interruption is permitted in step S455, and the route guidance processing routine described later is executed in step S460 to guide the occupant to the destination along the secondary route. Regardless of whether or not the passenger wishes to leave immediately after boarding, the primary route is always searched, the searched primary route is displayed, and route guidance is started.
A secondary route from the temporary departure place to the destination may be searched, and the guidance route may be switched from the primary route to the secondary route at the temporary departure place.

FIG. 7 is a flow chart showing a route guidance processing routine. Interruption is prohibited in step S510, and in the following step S520, the traveling locus of the vehicle is obtained based on the traveling distance detected based on the pulse signal from the vehicle speed sensor 7 and the traveling direction detected by the direction sensor 3. The current position and heading of the vehicle are detected by map matching with road map data. At this time,
You may use the present position and advancing direction detected by GPS positioning calculation. In step S530, the current position mark is displayed according to the newly detected latest current position and traveling direction, and the process proceeds to step S540. Step S54
At 0, whether or not guidance is necessary is determined based on the searched primary or secondary route, the detected current position, and the road map data. For example, if the current position of the vehicle is immediately before the intersection on the searched route (for example, before 300M), the occupant should be guided by indicating whether to go straight, turn right, or turn left at the next intersection. If such guidance is required, the process proceeds to step S550, and if not, step S550 is skipped. In step S550, CR
At T18, an enlarged view of the intersection that indicates the traveling direction is displayed, or the speaker 10 guides by voice. afterwards,
Interrupts are enabled in step S560, followed by step S560.
At 570, it is determined whether or not the vehicle has arrived at the destination. When the vehicle arrives at the destination, the process returns, otherwise step S510.
Then, the process returns to and the above process is repeated.

Next, a method of searching the primary route and the secondary route will be described. In the following, an intersection that satisfies a predetermined condition from among the intersections near the current location will be referred to as a departure intersection, and an intersection that satisfies the predetermined condition from among the intersections near the destination will be referred to as a destination intersection. For example, from the intersections around the current location, select the intersection that is located outside the circle with a predetermined radius centered on the current location and closest to the current location as the departure intersection, and select the destination from the intersections around the destination. An intersection existing outside the circle having a predetermined radius and being closest to the destination is selected as the destination intersection. Further, the intersections sequentially searched for in order to perform the route calculation are called central intersections, and the intersections adjacent to the central intersections are called adjacent intersections. Further, an intersection in front of each intersection on the optimum route from the departure intersection to each intersection is called an immediately preceding intersection.

In this route search, the search is advanced while recording the path g from the departure intersection to each intersection, the straight line distance h from each intersection to the destination intersection, and the intersection immediately before each intersection for each intersection. First, 0 is set to the path g of the departure intersection, a constant of infinity is set to the paths g of the other intersections, and the departure intersection is set to the central intersection to start the search. Next, one of the intersections adjacent to the central intersection is searched for, and the distance from the central intersection to the adjacent intersection is added to the distance g from the departure intersection recorded in the central intersection, The distance g = g1 from the departure intersection of the intersection is obtained and compared with the distance g = g2 from the departure intersection already recorded in the adjacent intersection. If the route g1 calculated this time is smaller than the previously recorded route g2, the route g of the adjacent intersection is rewritten to g1 and the central intersection is set to the intersection just before the adjacent intersection. Further, the straight line distance from the adjacent intersection to the target intersection is set to h. When the above processing is completed for all the adjacent intersections adjacent to the central intersection, the intersection having the smallest (g + k · h) is selected as the next new central intersection among all the intersections except the intersection already selected as the central intersection. Set to. Here, k is a directivity coefficient, and the larger the coefficient k, the stronger the directivity in the route search. In this embodiment, for example, the primary route is searched with k = 1.7, and the secondary route is searched with k = 1. Hereinafter, the above processing is performed on the intersections adjacent to the new central intersection.

FIG. 8 is a diagram for explaining the primary route search and the secondary route search. The search range of the primary route with k = 1.7 (shown by the solid line) is narrower than the search range of the secondary route with k = 1 (shown by the broken line), and the search of the primary route is secondary by that amount. The search time is shorter than the route search. However, on the other hand, a sufficiently accurate optimum route is not always searched. The larger the directivity coefficient k, the narrower the search range and the shorter the search time, but the optimality of the route of the search result deteriorates. On the other hand, since the secondary route searches a sufficiently wide range, it takes a long time to search, but the optimum route can be searched. In this way, a new central intersection is set in ascending order of (g + k · h), and a route search is performed. When the central intersection reaches the target intersection, the search is terminated. And
When the destination intersection is followed by the previous intersection in sequence, the vehicle reaches the departure intersection, and that route is the optimum route with the minimum distance from the departure intersection to the destination intersection.

9 and 10 are flowcharts showing the route calculation processing routine. This route calculation processing routine is a common calculation routine for the above-mentioned primary route and secondary route. When the primary route is searched, this routine is executed with k = 1.7, and when the secondary route is searched, k = 1. To execute this routine. Further, FIG. 11 is a diagram showing an example of an intersection network for explaining a method of searching for an optimum route. In FIG. 11, circles and the numbers in the circles represent the intersections and their numbers, and the numbers on the lines connecting the intersections represent the distances from the intersections to the intersections. Furthermore, FIGS.
Is a route search result recorded in the S-RAM 24. In these figures, (a) is a list recording route information, and this route information list includes each intersection around the current location, a path g to those intersections, an immediately preceding intersection on a route leading to each intersection, and each intersection. The straight line distance h from the intersection to the destination intersection is recorded. Further, (b) is a list showing the intersections of the central intersection candidates, and the intersection number of the central intersection candidate and (g + kh) are included in the central intersection candidate list.
Is recorded. 12 to 16 show (g + k · h) in the case of the primary route of k = 1.7. The route calculation process will be described with reference to these figures.

In step S605, the departure intersection and the destination intersection are specified as described above. Now, suppose that the intersection 1 is selected as the departure intersection as shown in FIG. Next, in step S610, the departure intersection is set as the central intersection. In the example of FIG. 11, the departure intersection 1 is the central intersection. In a succeeding step S615, the S-RAM 24
Initializes various data of the route information list of. That is, as shown in FIG. 12A, 0 is set for the journey g of the departure intersection and a very large value + ∞ is set for the journeys g of all the other intersections.

In step S620, one of the intersections adjacent to the central intersection is selected. In the following step S625, a value obtained by adding the distance from the central intersection to the selected adjacent intersection to the distance g of the central intersection is D−
Temporarily stored in RAM 22 as route A, and step S63
Go to 0. In step S630, this route A is compared with the route g of the selected adjacent intersection. If the former is smaller, the process proceeds to step S635, and if not, the step S655.
Go to. When the route A is smaller than the route g of the selected adjacent intersection, the route A is set to the route g of the selected adjacent intersection in step S635. The processing steps of steps S620 to S635 will be described with reference to the example of FIG. 11. 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 A = the route g = 0 of the central intersection 1 (see FIG. 12A) plus the route 2.5 from the central intersection 1 to the selected adjacent intersection 2 =
2.5 and the distance g = ∞ of the selected adjacent intersection 2 (see FIG. 12).
(See (a)), the former is smaller,
As shown in 2 (a), the route g = ∞ of the selected adjacent intersection 2 is changed to the route A = 2.5.

Next, in step S640, the central intersection is set to the intersection just before the selected adjacent intersection. In the example shown in FIG. 11, as shown in FIG. 12A, the intersection number of the central intersection 1 is recorded in the column of the intersection just before the selected intersection 2 in the route information list. In step S645, it is determined whether or not there is an adjacent intersection currently selected in the candidate list of central intersections. If it does not exist, the process proceeds to step S650, and if it exists, step S650 is skipped. In step S650, the currently selected adjacent intersection is added to the central intersection candidate list. In the example shown in FIG. 11, since the currently selected adjacent intersection 2 is not yet present in the central intersection candidate list, the number of the adjacent intersection 2 is recorded in the central intersection candidate list shown in FIG. 12B.

In step S655, it is determined whether or not the above examinations have been carried out for all the intersections adjacent to the central intersection, and if the examinations have been completed, the operation proceeds to step S660, and if not, the operation returns to step S620 to perform the above operation. Repeat the process. 12A and 12B show the stored contents of the S-RAM 24 at the time when the above-described processing is completed for the adjacent intersections 2 to 5 of the central intersection 1. The path g of each adjacent intersection 2 to 5 and the preceding intersection 1 are set in the route information list, and the intersections 2 to 5 of the central intersection candidates are recorded in the central intersection candidate list.

When the above processing is completed for all the adjacent intersections of the central intersection, the smallest (g + kh) intersection in the candidate list of central intersections is set as a new central intersection in step S660, and step S665. Go to. In step S665, the intersection newly selected as the central intersection is deleted from the central intersection candidate list. Next, in step S670, it is determined whether or not the intersection newly selected as the central intersection is the target intersection. If it is the target intersection, the process proceeds to step S675, and if not, the process returns to step S620. In the example shown in FIG. 11, the directivity coefficient k =
At the time of the primary search of 1.7, (g + kh) = 21.5 of the adjacent intersection 5 is the minimum among the adjacent intersections 2 to 5 recorded in the center intersection candidate list of FIG. The adjacent intersection 5 is determined as a new central intersection, and the intersection 5 is deleted from the central intersection candidate list. FIG. 13 shows the contents stored in the S-RAM 24 in that state.

Next, returning to step S620, the above processing is performed for the newly selected central intersection. In the example of FIG. 11, the adjacent intersections of the newly selected central intersection 5 are the intersections 1, 4, 6, and 7. When the above-described processing is performed on these adjacent intersections, the route information list of the S-RAM 24 is displayed. And the candidate list of central intersections is as shown in FIG. In the central intersection candidate list shown in FIG. 14 (b),
At the time of primary route search of k = 1.7, (g + k
h) = 20.2 is the minimum and selects intersection 7 as the new central intersection. Since this new central intersection 7 is not the destination intersection, the process returns from step S670 to step S620, and when the above-described processing is performed on the adjacent intersections 5, 6, 9 of the central intersection 7, the route information list of the S-RAM 24 and the central intersection 7 are displayed. The candidate list is as shown in FIG. In the central intersection candidate list shown in FIG. 15B, k =
1.7 (g + k · h) = at intersection 9 when searching for the primary route
20.2 is the minimum and selects intersection 9 as the new central intersection. Since this new central intersection 9 is not the destination intersection, the procedure returns from step S670 to step S620.
When the above-described processing is performed on the adjacent intersections 7, 8, 10 and 12 of the central intersection 9, the route information list and the central intersection candidate list of the S-RAM 24 are as shown in FIG.
In the central intersection candidate list shown in FIG. 16B, k =
1.7 (g + k · h) at intersection 10 when searching for the primary route
= 15.5 is the minimum, and the intersection 10 is selected as the next central intersection. However, the newly selected central intersection 1
0 is a destination intersection, and since the central intersection has reached the destination intersection, the route calculation process is terminated and the process proceeds to step S675.

In step S675, FIG.
The route information list of the S-RAM 24 shown in is searched, and the preceding intersection is sequentially traced starting from the target intersection 10. That is, the intersection just before the destination intersection 10 is the intersection 9
The intersection just before this intersection 9 is the intersection 7,
The intersection just before the intersection 7 is the intersection 5, and the intersection just before the intersection 5 is the intersection 1, that is, the departure intersection. This route, 10 → 9 → 7 → 5 → 1 is the primary route from the departure intersection 1 to the destination intersection 10.

The search for the secondary path is performed by referring to FIGS.
This is similar to the calculation processing of the primary route shown in 0, but since the directivity coefficient k becomes 1, the central intersection is selected from a wide range as shown in FIG.
That is, the searched route is different from the above-mentioned primary route. In addition,
In the example of the intersection network shown in FIG. 11, the case where the number of intersections is small has been described in order to make the explanation easy to understand. Therefore, the primary route and the secondary route are the same as the search result. Since the number of intersections is not small like in the network example, different search results are obtained in the primary route search and the secondary route search.

As described above, when the occupant in the vehicle desires to immediately leave, the primary route is searched by performing a highly directional route search with the directivity coefficient k = 1.7 from the current location, While displaying the searched primary route on the road map and starting the guidance immediately, a temporary departure value is set on the primary route, and the directivity coefficient k from the temporary departure value to the destination is set.
Since the route search having a lower directivity than the primary route search of = 1 is performed to search for the optimum secondary route, the primary route displayed at the temporary start value is switched to the secondary route to continue the guidance. The primary route is searched for in a short time, and after the occupant gets on the vehicle, the primary route is displayed immediately and the route guidance is started without waiting for a long time for the route search. Also,
Since the secondary route is searched by a search method with a lower directivity than the primary route, the optimal route is searched, and the display route is switched from the primary route to the secondary route from the temporary departure point to become the optimal secondary route. The route guidance to the destination is performed along the route.

Next, a modified example of the above-described embodiment in which the route near the target intersection is accurately searched for in the search of the primary route will be described. In the above-described embodiment, the search is started from the departure intersection when the primary route is searched, and the search is terminated when the destination intersection is reached. Then, as described with reference to FIG. 8, the search range is widest in the vicinity of the current position and becomes narrower toward the destination. In other words, it is difficult to obtain an accurate route near the destination because only a narrow range is searched, and on the other hand, an accurate route is easily obtained because a wide range is searched near the current position. Therefore, in this modified example, when the primary route is searched, the search is started from the target intersection and the search is ended when the departure intersection is reached. As a result, the search range becomes the range shown in FIG. 17 in which the starting point and the destination of FIG. 8 are replaced,
The closer to the destination, the wider the search range. That is, since the search is performed from a wide range near the destination, an accurate route can be obtained.

Now, a case where a primary route is searched from a starting point to a destination on the road map shown in FIG. 18 by the above primary route searching method will be described. In the method of the above-described embodiment in which the route search is performed from the departure point to the destination,
The primary route as shown by the bold line is searched. On the other hand, in the method of the modified example in which the route is searched from the destination toward the departure point, the primary route as shown by the bold line in FIG. 20 is searched. By the way, the shortest route from the starting point to the destination is shown in Figure 2.
The route is as shown in 1. That is, the shortest route is obtained near the destination in the search result of the modified example in which the route is searched from the destination toward the departure place.

22 and 23 are flow charts showing a route calculation processing routine of the above-described modified example in which the route is searched from the destination to the departure place. This processing routine is the same as the processing routine of the embodiment shown in FIGS. 9 and 10, except that the departure intersection and the destination intersection are replaced with each other, and a description thereof will be omitted.

In the configuration of the above embodiment, the CD-RO
M16 is a map storage means, key 8 is a destination setting means,
The CPU 1, the azimuth sensor 3, the vehicle speed sensor 7, the GPS receiver 12, the receiver 14 and the antenna 15 constitute a current position detecting means, the CPU 1 constitutes a primary route searching means and a secondary route searching means, and the CRT 18 constitutes a display means.

[0038]

As described above, according to the invention of claim 1, a highly directional route search is performed to search for a primary route from the current position to the destination, and the searched primary route is displayed on the road map. At the same time, a temporary departure place is set on the primary route, and a route with a lower directivity than that during the primary route search is performed to search for a secondary route from the temporary departure place to the destination, and the vehicle When the route is reached, the route being displayed is switched from the primary route to the secondary route, so the search for the primary route is completed in a short time, and after the passenger has boarded the vehicle, there is no need to wait a long time for route search. , The primary route is displayed immediately and route guidance is started. In addition, the optimal route is searched for the secondary route from the temporary departure value to the destination, and the display route is switched from the primary route to the secondary route at the temporary departure place, and the optimal secondary route is reached to the destination. Route guidance is performed. According to the second aspect of the present invention, the secondary route search time is predicted, and the point on the primary route reached when the secondary route search ends is set as the temporary departure point. The guidance by is limited to the minimum necessary range, and the guidance range by the optimal secondary route is widened to perform proper route guidance. According to the invention of claim 3, the search time of the secondary route is predicted based on the straight line distance from the current position to the destination and the number of intersections existing between the two points. Since the secondary route is the route from the temporary starting point to the destination, the route search time from the temporary starting point to the destination should be predicted, but since the temporary starting point itself has not been determined, the temporary starting point is The route search time from the current location to the destination is predicted based on the straight line distance from the current location to the destination and the number of intersections existing between the two locations. In this way, the estimated search time will be longer by the search time from the current location to the temporary departure point, but the search time on the secondary route is so short that it can be ignored compared to the traveling time from the current location to the destination, so the temporary departure point is near the current location. It is possible that the search time of the secondary path can be reasonably predicted. According to the invention of claim 4, a predetermined time is set as the expected search time of the secondary route. Since the search time of the secondary route in the normal route guidance ends within 5 to 10 minutes, the search time can be predicted in a short time by setting the predicted search time of the secondary route to a predetermined time longer than that. According to the invention of claim 5,
When searching for the primary route, start the search from the current location, and select an intersection with a small total value (g + kh) of the distance g from the departure intersection around the current location and k times the linear distance h to the destination intersection around the destination. Since the search is performed sequentially until the target intersection is reached, the route search is performed in a wide range around the current location, and the optimum route is searched. In other words, since the temporary departure point is close to the current location, the optimal primary route from the current location to the temporary departure point is searched, while the optimal secondary route from the temporary departure point to the destination is searched, so that the occupant can enter the vehicle. Route guidance is started immediately after boarding, and guidance is performed along the optimal route from the present location to the destination. According to the invention of claim 6, when the primary route is searched, the search is started from the destination and the route g from the destination intersection around the destination is set.
Since the total value (g + k · h) of the linear distance h to the departure intersection around the current location and the total value (g + kh) is smaller, the search is performed until the departure intersection is reached. And the exact route around the destination can be searched. According to the invention of claim 7, since the value of k at the time of the primary route search is set to a value larger than the value at the time of the secondary route search, the primary route search is more directional than the secondary route search. Is high, the search is completed in a short time, and the waiting time of the occupant before the route guidance is started is shortened.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an embodiment.

FIG. 2 is a functional block diagram showing the configuration of one embodiment following FIG.

FIG. 3 is a flowchart showing a main program of a microcomputer.

FIG. 4 is a flowchart showing a current position calculation interrupt routine of the microcomputer.

FIG. 5 is a flowchart showing a destination setting processing routine of the microcomputer.

FIG. 6 is a flowchart showing a route calculation processing routine of the microcomputer.

FIG. 7 is a flowchart showing a route guidance processing routine of a microcomputer.

FIG. 8 is a diagram illustrating a search range of a primary route and a secondary route.

FIG. 9 is a flowchart showing a route calculation processing routine of the microcomputer.

FIG. 10 is a flowchart showing the route calculation processing routine of the microcomputer following FIG. 9;

FIG. 11 is a diagram showing an example of an intersection network.

FIG. 12 is a diagram showing a recording example of a route information list and a center intersection candidate list.

FIG. 13 is a diagram showing another example of recording of a route information list and a central intersection candidate list.

FIG. 14 is a diagram showing another example of recording of a route information list and a center intersection candidate list.

FIG. 15 is a diagram showing another example of recording of the route information list and the central intersection candidate list.

FIG. 16 is a diagram showing another recording example of the route information list and the central intersection candidate list.

FIG. 17 is a diagram illustrating a search range of a primary route and a secondary route of a modified example.

FIG. 18 is a diagram showing a road map for route search.

FIG. 19 is a diagram showing a search result when a primary route is searched by the search method of the embodiment on the road map shown in FIG. 18;

FIG. 20 is a diagram showing a search result when a primary route is searched by the search method of the modified example of the embodiment on the road map shown in FIG. 18;

FIG. 21 is a diagram showing the shortest route from a starting point to a destination in the road map shown in FIG.

FIG. 22 is a flowchart showing a route calculation processing routine of a modified example of the embodiment.

FIG. 23 is a flowchart showing a route calculation processing routine of a modified example of the embodiment, following FIG. 22;

[Explanation of symbols]

 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 100 Vehicle route guidance device

Claims (7)

[Claims] 1. A map storage means for storing a map, a destination setting means for setting a destination, a current location detecting means for detecting a current location of a vehicle, and a route search with high directivity to perform the destination from the current location. Primary route searching means for searching a primary route to the ground, temporary departure place setting means for setting a temporary departure place on the primary route searched by the primary route searching means, and directivity more than the primary route searching means. A secondary route searching means for performing a low route search to search for a secondary route from the temporary departure point to the destination, and displaying the primary route on a road map read from the map storage means, wherein the vehicle is A route guide device for a vehicle, comprising: a display unit that switches the route being displayed from the primary route to the secondary route when the vehicle reaches the temporary departure place. 2. The vehicle route guidance device according to claim 1, wherein the temporary departure point setting means predicts a secondary route search time by the secondary route search means, and the secondary route search is completed. A route guidance device for a vehicle, wherein a point on the primary route that is reached at the time of setting is set as a temporary departure place. 3. The vehicle route guiding apparatus according to claim 2, wherein the temporary departure place setting means is a secondary vehicle based on a straight line distance from the current position to the destination and the number of intersections existing between the two points. A vehicle route guidance device characterized by predicting a route search time. 4. The vehicle route guiding apparatus according to claim 2, wherein the temporary departure place setting means sets a predetermined time as an expected search time of the secondary route. 5. The vehicle route guidance device according to claim 1, wherein the primary route search means starts the search from the current location, and a route g from a departure intersection around the current location. And k times the linear distance h to the target intersection around the destination (where k> 0) and the total value (g + k · h) is smaller, the search is sequentially performed until the destination intersection is reached. A vehicle route guidance device characterized by the above. 6. The vehicle route guidance device according to claim 1, wherein the primary route search means starts a search from the destination and starts from a destination intersection around the destination. Search sequentially for intersections with a small total value (g + kh) of the route g and the linear distance h to the starting intersection around the present location (k + 0), and search until the starting intersection is reached. A route guidance device for a vehicle, which is characterized by being performed. 7. The vehicle route guiding apparatus according to claim 5, wherein the primary route searching means sets a value larger than a value of k at the time of secondary route searching. Vehicle route guidance device.