JPH01119898A - Vehicle navigation system - Google Patents

Abstract

PURPOSE:To guide a vehicle on a route with a minimum time by retrieving the combination of road segments to arrive at an aimed point, and extracting the route to take the minimum time based on the required running time of the respective road segments. CONSTITUTION:When the aimed point is designated, a retrieving range limiting device 5 limits the retrieving range based on a straight line distance between a present position and the aimed position, a route retrieving device 6 reads data in the limited range out of the road network data stored in a map memory 3, and retrieves a route set to arrive at the aimed point. Next, a route extracting device 7 reads the required traveling times of respective road segments, sums up the required traveling times of the respective road segments, calculates the required time of the respective route sets, mutually compares the required times of the respective route sets, and selects the route to take the minimum time. Further, the signal to emphatically display the guiding route selected as mentioned above in a guiding device 10 is supplied to a display 1, and the vehicle is guided.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an in-vehicle navigation system, and more specifically, it detects the current position based on the cumulative distance and cumulative direction of driving, and This invention relates to an in-vehicle navigation system that displays the current location, destination, and route to the destination on a road map.

<Prior Art> An on-vehicle navigation system displays the current position of a vehicle on a guidance route to facilitate driving in unfamiliar areas or at night. And recently,
When multiple intersections and roads connecting intersections are digitized and displayed on a screen, and the driver sequentially specifies the intersections displayed on this screen to create a guidance route and guide the vehicle, the above guidance is used. There is an in-vehicle navigation system that displays a route on a screen and, when the vehicle approaches the specified intersection, uses voice and screen to instruct the vehicle in which direction it should proceed next, guiding the vehicle. 80-200399).

As shown in the block diagram of FIG. 7, the above navigation system includes a road map storage means (1') storing a road network, an intersection designated from the road network, and a designated intersection. Display means (2') for displaying adjacent intersections and road segments connecting the intersections
a designation means (3') for sequentially designating the intersections to be passed among the displayed intersections; and a route storage means (4') for inputting the sequentially designated intersections and storing a route connecting each intersection. , a current position detecting means (5') for detecting the current position of the vehicle based on the changed direction and the changed distance from the time of initial setting, and display means for displaying the route created above, and when approaching the intersection to be passed, the above-mentioned Display switching means (2') for switching the display on the display means (2') to the display of the designated intersection and intersections adjacent to the designated intersection;
6').

To explain in more detail the road map data stored in the road map storage means (1'), as shown in FIG. Group of pages (Figure 8 (a) (b)
)), a block group in which each of the divided areas is further divided into blocks (see Fig. 8(C)), and an intersection group in which the intersections existing in each area of the block are classified by number (Fig. 8(d)). (See (e))

In addition, each of the memory areas of the intersection group that has been reduced has a
Data regarding the number, direction, and distance of each intersection and adjacent intersections is stored.

When creating a guidance route using the above navigation system, the relevant page, relevant block, and intersection closest to the current location are sequentially designated from the road map stored in the road map storage means (1'), and then the current location is The closest intersection and multiple adjacent intersections are displayed on the screen along with the route, and the driver specifies one of the adjacent intersections displayed on the screen. Then, the adjacent intersection designation operation is repeated until the destination is reached, and a guidance route is created. That is, the above-mentioned - group of intersections are arbitrarily designated by the driver based on data regarding numbers, directions, and distances stored in the road map storage means (1').

When the driver starts the guidance system, the display means (2) displays the estimated current position detected based on the memorized guidance route, the cumulative distance traveled from the initial setting position, and the cumulative direction. ’). When the vehicle approaches the designated intersection, the driver is informed via voice or screen that the vehicle is approaching the designated intersection and the next direction of travel. Switch to the screen showing the intersection.

However, the recent increase in the number of vehicles has been remarkable, and the overcrowding of vehicles has accelerated traffic congestion.
A problem with guidance routes that are physically created based on road map data stored in the system is that even if a guidance route with the shortest distance can be created, it does not necessarily mean that the destination will be reached quickly.

In order to solve this problem, one possible method is for a central control station to judge the current road congestion situation and communicate wirelessly with vehicles to detour around congested sections, but each vehicle's destination is Each route is different, and there is a problem of not knowing the appropriate detour.

<Objective of the Invention> The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide an on-vehicle navigation system that can guide a vehicle along the shortest route.

Means for Solving the Problems> To achieve the above object, the vehicle-mounted navigation system of the first invention includes at least a specifying means for specifying a destination, a road network, and roads constituting the road network. a first storage means storing information regarding the segment;
a second storage means that stores information regarding the required travel time of each road segment; a route search means that searches for a combination of road segments that can reach a destination based on the road network; and a required travel time of each road segment. and a route extracting means for extracting a route corresponding to the shortest required travel time based on data regarding the vehicle.

However, the route extraction means may calculate the required travel time for each route, compare the required travel times, and extract the shortest route.

Further, the route search means may limit the route search range based on the straight-line distance between the current location and the destination.

Furthermore, the second storage means includes a storage medium storing data representing the required travel time of the road segment traveled at a predetermined time, and a storage medium storing an increase/decrease in the required travel time for each guided route travel. It is preferable that data representing the required travel time of a road segment is set for each month, day of the week, and time zone.

A vehicle-mounted navigation system according to a second aspect of the present invention includes at least a specifying means for specifying a destination, a first storage means for storing information regarding a road network and road segments constituting the road network, and a required travel time of the road segment. a second storage means for pre-storing information regarding the road network; a road data acquisition means for acquiring data regarding the road network from the outside and new information regarding the required travel time of the road segment from the outside; a route search means for searching for a combination of route units that can reach the destination based on the road network;
and a route extracting means for extracting a route corresponding to the shortest required travel time based on the data regarding the required travel time of each road segment from the new data storage means.

However, the route extraction means may calculate the required travel time for each route, compare the required travel times, and extract the shortest route.

Further, the route search means may limit the route search range based on the straight-line distance between the current location and the destination.

Furthermore, the second storage means includes a storage medium storing data representing the required travel time of the road segment traveled at a predetermined time, and a storage medium storing an increase/decrease in the required travel time for each guided route travel. It is preferable that data representing the required travel time of a road segment is set for each month, day of the week, and time zone.

Further, the road data acquisition means may be a wireless device.

Further, the second storage means may be a removable RAM, and information regarding the required travel time of the road segment may be loaded from the outside.

Further, the new data storage means may store an increase/decrease in the required travel time of the road segment stored in the second storage means.

In the above-described in-vehicle navigation system, in response to the destination specified by the driver, the route search means searches for a combination of road segments that can reach the destination based on the road network. Next, in the route extraction means,
For each of the above-mentioned searched routes, data regarding the required travel time of the road segment in the segment corresponding to the time designated as the destination is read from the second storage means, and the shortest route is determined based on the required travel time of each road segment. Extract the route corresponding to . Then, along with the shortest route searched above, the current position detected based on the cumulative distance traveled and the cumulative direction is displayed on the road map.
Vehicles can be guided along the shortest route.

The same effect as described above can also be achieved when the route extracting means calculates the required travel time for each road segment and compares the required travel times to extract the shortest route.

In addition, if the route search method limits the route search range based on the straight-line distance between the current location and the destination, the number of routes may be limited when there are many routes that can reach the destination. However, the time required for route search and route extraction processing can be reduced.

Furthermore, the second storage means includes a storage medium storing data representing the required travel time of the road segment traveled at a predetermined time, and a storage medium storing an increase/decrease in the required travel time for each guided route travel. In this case, the increase or decrease in the required travel time as a result of traveling on each of the above-mentioned routes can be stored as new data. Therefore, when creating a route next time, a more accurate shortest time route can be created based on data that takes into account increases and decreases.

Furthermore, if data representing the required travel time of a road segment is set for each month, day of the week, and time zone, the shortest route may be selected according to seasons, holidays, rush times, etc. Can be done.

In addition, the second invention includes a road data manual means and a new data storage means in addition to the in-vehicle navigation system of the first invention, and the road data acquisition means allows external (for example, traffic control) Data on the road network and the required travel time for road segments are obtained from local government agencies, etc., and stored in a new data storage means, so the data can be changed to respond to changes due to various social circumstances. can do.

That is, based on the new road segment stored in the new data storage means and the road segment stored in the first storage means, the route search means searches for a combination of route units from the current location to the destination. However, the route extraction means can create a route corresponding to the shortest time route based on the required travel time data for each road segment, including new data obtained by the road data acquisition means, so the driver can It is possible to travel on a route that adapts to road conditions that change according to social life, and to reach the destination quickly.

If the road data acquisition means is a wireless device, as long as the power is turned on to the wireless device, new data regarding the required travel time for a given road segment can be obtained from the outside (control station). can.

Further, if the second storage means is a removable RAM and is used to load data regarding the required travel time of the road segment from the outside, the control station,
Alternatively, the data can be obtained via an information relay from the control station, and the configuration of the road data obtaining means on the vehicle side can be simplified.

Furthermore, if the new data storage means stores the increase/decrease in the required travel time of the road segment stored in the second storage means, the amount of data is small compared to transmitting all the data. This reduces the communication time required for data transmission.

<Embodiments> Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows a block diagram of an in-vehicle navigation system according to the first invention, and the in-vehicle navigation system includes:
A display device (1), a designation device (2) that performs initial settings such as designation of the planned driving range and destination, and a map memory that stores information about the road network and the road segments that make up the road network. (3), the required time memory (4) that stores the required travel time for the above road segment for each month, day of the week, and time zone, and calculate the straight line distance between the current location and the destination. a search range limiting device (5) that limits the route search range based on the search range, and a search range limiting device (5) that limits the route search range based on the above-mentioned limited range, and all road segments from the current location to the destination based on the road network stored in the map memory (3). (hereinafter referred to as a route set); a route extraction device (7) that extracts a route set corresponding to the shortest route based on the required travel time of road segments; A current position detection device (8) that calculates the cumulative direction and distance associated with the current position and detects the estimated current position.
and an emphasis signal generation device (9) that generates a signal for highlighting the shortest route and estimated current position on the road network.
The vehicle is guided by supplying a signal that highlights the shortest route and estimated current position on the road network to the display (1), and stores the actual travel time on each road segment in the required time memory (1). 4) Guidance device (1) stored in
0).

More specifically, the display device (1) has a displayable liquid crystal screen. In addition, C as an indicator (1)
It is also possible to use an RTSEL display or the like.

The designated device (2) uses the screen input method and has a display (1).
), on which transparent electrodes (not shown) are arranged in a matrix, and a touch panel (21) is used to designate a destination, etc. by touching the display position of a road network, parameters, etc. displayed in response to a key operation; A point specification key (22) for specifying a destination, and a parameter setting key (22) for setting parameters for route search such as road type and road width.
23), a guidance key (24) that displays the road network, guidance route, estimated current position, etc., and a cursor key (
25) (see Figure 2).

The map memory (3) consists of a large-capacity memory that stores Japanese road maps, and a compact disk ROM, optical hard disk, etc. is used as this memory. The storage structure of the map memory (3) will be explained in detail with reference to FIG. 3. A group of pages (see FIG. 3 ( a)
(b)), a block group (see Fig. 3 (e)), which is obtained by further dividing each of the divided areas into blocks (see Fig. 3 (e)), and a road network, intersection, place name, railway transportation network, etc. in each area of the block. In addition to layer groups classified by building names (see Figure 3 (d)), the road network is segmented by intersection, and classified into expressways, national roads, and local roads according to road type. The stored road segment group (see Fig. 3(e)) and the road segment data group (see Fig. 3(f) If the above data is changed, or if a new road is added, it is possible to provide a RAM for storing the change information, new road information, etc.

The required time memory (4) stores the required travel time for each month, day of the week, and time period, which is statistically calculated based on the results of actual driving on the road segments in the map memory (3) within a predetermined period. The road segment includes a ROM (41,) that stores the increase/decrease in the travel time required for each road segment after the actual driving by the driver (see Fig. 3 (g)). . The RAM (42) is I
A memory with a large storage capacity, such as a C card, is used, and data regarding the new required travel time can be written by an external writing device.

The search range limiting device (5) is a transparent touch panel (21)
a distance calculating unit (51) that calculates the straight line distance between the current location and the destination based on the coordinate position of the destination output from the , and multiplying the straight line distance by a predetermined number and defining the straight line multiplied by the predetermined number as a diagonal line. Range setting section (5) that limits the search range to a rectangular range
2).

The route search device (6) selects roads within the above-mentioned limited range from the map memory (3) in response to a signal for setting a route such as road type and road width by operating a parameter key (23) (see Fig. 3).
f)). Incidentally, when the above-mentioned data is changed, or when a new road or the like is added, it is also possible to provide a RAM for storing the above-mentioned change information, new road information, etc.

The route extraction device (7) includes a clock (71) and a clock (71).
) The required travel time of each road segment constituting each route set is stored in the required time memory (4).
) and calculates the required travel time for each route by summing the required travel time for each road segment and comparing the required travel times for each route output from the totalization unit (72). The route selection unit (
73) and a temporary storage section (74) that temporarily stores the selected optimal route.

That is, the totalizing unit (72) reads the required travel time of the road segment in the time period corresponding to the time when the destination is specified, and sequentially calculates the travel time of each road segment from the first one, taking into consideration the passing time of each road segment. The required travel time for each segment is totaled.

The current position detection device (8) includes a direction sensor (81) that detects the traveling direction of the vehicle based on geomagnetism, a mileage sensor (82) that detects the mileage from a wheel drive device, etc. It has an integrator (83) that integrates the cumulative direction and travel distance, and an estimated current position generator (84) that outputs estimated current position data based on the integrated data.

The emphasis signal generation device (9) includes a route highlighting unit (91) that generates a signal that highlights the shortest route selected by the route extraction device (7), and current position data from the current position detection device (8). It has a current position emphasizing section (92) which receives as input and generates a signal that blinks and displays the estimated current position.

The guidance device (10) displays the road network on which the vehicle is to be traveled in response to a guidance start signal from the guidance start key (24).
, and a signal for blinking the estimated current position from the current position emphasizing unit (92) to the display (1),
A signal is supplied to the display (1) to highlight the shortest route generated in response to the destination specification. Then, the increase/decrease in the required travel time for each road segment actually traveled is R
It is stored in A M (42).

The operation of the in-vehicle navigation system having the above configuration will be explained.

If there is no initial setting input, the road network you are driving on will be displayed and your estimated current position will be highlighted, and if there is initial setting input, the shortest route to the destination will be created and the above It guides the vehicle by displaying the shortest route along with the road network and estimated current location. That is, when the driver specifies a destination, the search range limiting device (5) limits the search range based on the straight-line distance between the current location and the destination, and the route search device (6) stores the map memory (3). )
Among the road network data stored in the system, data within a limited range is read out and a set of routes that can reach the destination is searched.

Next, the route extraction device (7) reads the required travel time for each road segment in the classification (month, day of the week, time zone) corresponding to the time when the destination is specified from the required time memory (4), and calculates the required travel time for each road segment. The required travel time for each route set is calculated by summing the required travel time, and the required time for each route set is compared to select the shortest route to the destination. Then, the emphasis signal generation device (9) generates a signal that highlights the selected guidance route, and
), a signal highlighting the guidance route is displayed on the display (1
) to guide vehicles.

More specifically, the destination designation key (22) of the designation device (2) is turned on, and the destination is input by touching a predetermined position on the displayed road network. Next, when the parameter key (23) is turned on, route search parameters such as road type and road width are displayed, and by touching the predetermined road type and road width position, Set the route. When the initial setting operation by the driver is completed as described above, the route limiting device (5) multiplies the straight line distance between the current location and the destination by a predetermined number, and then creates a rectangular range whose diagonals are Limit the route search range,
The route search device (6) reads road segments of the set road type and road width from the map memory (3), and searches for all route sets that can reach the destination within the above-mentioned limited range. Next, the summation unit (72) of the route extraction device (7)
, for the road segments of each route mentioned above, the required travel time in the category (month, day of the week, time zone) corresponding to the time when the destination is specified is read from the required time memory (4), and the total required time for each road segment is calculated. to obtain the required time for each path set, and then the path extractor (force selection part)
In step 73), the time required for each route set sequentially calculated by the summation unit (72) is compared to select the shortest route.

Then, the emphasis signal generation device (9) generates a signal that highlights the selected shortest time route.

Then, the driver operates the guidance key (24) to start the guidance program, and the guidance device (10)
In addition to displaying the road network on the display (1), a signal from the emphasizing signal generating device (9) that highlights the shortest route and a signal that flashes the estimated current position are sent to the display (1). supply and start guiding the vehicle. While the vehicle is being guided, each time the vehicle reaches the end point of each road segment, the increase or decrease in the required time of the road segment actually traveled is stored in RAM (42).

The shortest time route creation and vehicle guidance procedures will be explained in detail based on the flowchart of FIG. 4.

In step (2), it is determined whether or not there is an initial setting input such as a destination from the designation device (2), and if there is no input, the driving schedule or the road network currently being traveled is displayed. In ■, the increase/decrease in the required travel time for each road segment actually traveled is calculated as RAM (4
2).

Further, in step (2) above, if there is an initial setting input such as a destination, then in step (2), a road segment that meets the setting conditions is read out.

Next, in step (2), the required travel time of the road segments is read, and in step (2), a route set that can reach the destination is searched for by combining the road segments.

Next, in step ■, for each route set,
The required travel time is sequentially calculated by summing the required travel time for each road segment.

Then, in step ■, select the shortest route,
In step ■, the shortest time route is stored in the temporary storage section (74
), the shortest time route is displayed in step [stock], and the process of step (2) is performed. In step ■, it is determined whether or not the destination has been reached. If it is determined that the destination has not been reached, the process of step ■ is repeated, and if it is determined that the destination has been reached, in step ■ The increase/decrease in the travel time required for each road segment actually traveled is stored in the RAM (42), the shortest time route stored in the temporary storage section (74) is deleted in step (2), and the processing in step (2) is performed. conduct.

In summary, after the driver specifies a destination, etc., the search range limiting device (5) limits the route search range based on the straight-line distance between the current location and the destination, and the route search device (6) Based on the road network stored in the map memory (3), all routes that can reach the destination are searched within a limited range, and the route extraction device (7) searches for the required time stored in the memory (4). The required travel time for all of the routes is calculated based on the travel time required for each road segment, and the shortest route is selected by comparing the required travel times of all routes. And an emphasis signal generation device (9)
At , a signal is generated that highlights the shortest time path.

Next, in response to the guidance start signal, the guidance device (10) displays the shortest route as well as the current position of the vehicle on the display device (1).
By highlighting this, the vehicle can be guided along the shortest route. That is, unlike a system that simply uses the shortest physical distance between the current location and the destination as the guidance route, the shortest time between the current location and the destination is calculated based on the past travel time required for each road segment. It can be displayed by route. Further, since the increase/decrease in the actual required travel time for each road segment of the route is written into the required time memory (4), it is possible to cope with the road conditions that change day by day.

It should be noted that the first invention is not limited to the above-mentioned embodiments, and for example, when an in-vehicle navigation system is provided with a receiving function and sudden information such as an accident is obtained while driving along the above-mentioned guidance route. It is possible to extract a new shortest route from roads other than the route where the failure occurred, and also to determine whether the end point of each road segment has been approached, and if it is determined that the end point has been approached, It is possible to indicate the direction of travel by displaying the next road segment with blinking or arrow display, and it is possible to make various other design changes within the scope of not changing the gist of the present invention. .

FIG. 5 shows a process diagram of an embodiment of the second invention,
The difference from the first invention is that a roadside beacon (A) is installed at a predetermined position on the road network to transmit data regarding the road network collected by the control station and data regarding the required travel time of the road segment. The vehicle is equipped with a receiver (20) that receives radio waves from a roadside beacon, and a RAM (30) that stores new data from the receiver (20).

Control stations measure vehicle speeds and traffic volume using vehicle detectors on the road traffic network, de Sopra radar, etc., and it is easy to calculate data on the travel time required for road segments based on the above data. There is a transmitter from the control station that transmits the increase/decrease from the conventional data by radio waves.

The receiver (20) receives data from the control station via the roadside beacon, and extracts data regarding the road network and data on increases and decreases in the required travel time of road segments from the received signal.

RAM (30) c) Stores the data extracted by the receiver (20) and uses it as route search and shortest route extraction data. Note that this RAM (30) can also be replaced with RAM (42) of the required time memory (4).

The shortest route creation and vehicle guidance procedure of the embodiment of the second invention will be explained in detail based on the flowchart of FIG. The flowchart of the first embodiment of the invention is different only in that a received signal processing step is added after the processing of step (2) and before returning to the processing of step (2).

That is, after the process of step (2), it is determined in step (2) whether new data regarding the road network data and new data regarding the required travel time of the road segment has been received, and if it is determined that new data has been received, the step (2) is performed. The new data is stored in the RAM (30), and if it is determined that no new data has been received, the process of step (2) is repeated.

Then, the processing from step ■ to step ■ is the first step.
This is similar to the processing from step (2) to step (2) in the embodiment of the invention.

In summary, the receiver (20) receives data regarding the road network and signals regarding the required travel time of road segments sent from the control station, and stores the data in the RAM.
(30), and the route search device (6) searches for a combination of route units from the current location to the destination based on the data related to the new road network and the data stored in the map memory. The extraction device (7) can create a route corresponding to the shortest time route based on new required travel time data, so the driver can drive on a route that is responsive to road conditions that change according to social life. and can reach the destination quickly.

Note that the second invention is not limited to the above embodiment, and for example, instead of providing the receiver (20), an RA
M <30> Using a removable IC memory card, install a writer at a predetermined location on the road network (e.g. gas station, etc.) to relay data from the control station and write the data to the IC card. In addition, various design changes can be made without changing the gist of the invention.

<Effects of the Invention> −32= As described above, according to the in-vehicle navigation system of the first invention, after the driver specifies the destination, the route search means stores the destination in the road map storage means. A combination of road segments that can reach the destination is searched based on the road network, and the route extracting means selects one of the above-mentioned routes based on the data regarding the required travel time of the road segments stored in the required time storage means. By extracting the route corresponding to the shortest time route from , and displaying it on the display means, the vehicle can be guided along the shortest time route, so the driver can quickly reach the destination. be effective.

Further, according to the second invention, since traffic data that changes daily can be obtained by the road data acquisition means, a route corresponding to the shortest distance route is created based on the new data, and the driver can quickly reach the destination. It has the unique effect of being able to reach

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the in-vehicle navigation system of the first invention, FIG. 2 is a front view of a display device and a designation device, FIG. 3 is a diagram illustrating the storage configuration of a map memory, and FIG. 5 is a block diagram showing an embodiment of the in-vehicle navigation system of the second invention. FIG. 6 is a flow chart of the embodiment of the second invention. FIG. 7 is a conventional in-vehicle navigation system. System Block Diagram FIG. 8 is a diagram illustrating the storage configuration of a road map storage means of a conventional in-vehicle navigation system. (2)...Specification device, (3)...Map memory, (4)...Required time memory, (5)...Search range limiting device, (6)...Route search device, ( 7)...
Route extraction device, (9)... emphasis signal generation device,

Claims (13)

[Claims] 1. Total distance traveled and how to accumulate it The current position is detected based on the location, destination, and route to the destination. In-vehicle type that displays on a road map In navigation systems, At least a means of specifying a destination and a route. Road network and road segments that make up the road network The first record stores information about the storage means and the required travel time of the road segment. A second memory device that stores information about It is possible to reach the destination based on the road network. A route to search for a combination of route units Search methods and required travel for each road segment Minimum required based on data on row times Route to extract route corresponding to travel time A vehicle characterized in that it has extraction means. Onboard navigation system. 2. The route extraction means calculates the required distance for each route. Calculate the travel time and compare the required travel times. It compares and extracts the shortest route. A vehicle according to claim 1 above Onboard navigation system. 3. The route search method is between the current location and the destination Set the route search range based on the straight line distance of The scope of the above claims is limited. In-vehicle navigation system described in paragraph 1 Tem. 4. The second storage means runs at a predetermined point in time. The required travel time for the road segment a storage medium storing data represented; Increase/decrease in required travel time for each guided route run It consists of a storage medium that stores Vehicle-mounted type according to claim 1 above navigation system. 5. Represents the travel time required for a road segment The data to be displayed is set for each month, day of the week, and time of day. The scope of the above patent claims is The in-vehicle navigation system described in section 4 stem. 6. Total distance traveled and how to accumulate it The current position is detected based on the location, destination, and route to the destination. In-vehicle type that displays on a road map In navigation systems, At least a means of specifying a destination and a route. Road network and road segments that make up the road network The first record stores information about the storage means and the required travel time of the road segment. A second record that stores information regarding the on the road network from the outside and from the outside. data and the required travel of the road segment. Get new information about line times Means of obtaining road data and the new roads mentioned above a new data storage means for storing data; Possible routes to reach the destination based on the road network Route search method to search for unit combinations and the second storage means and the new data. of each road segment from the data storage means. Based on data on required travel time Disadvantages Extracting routes corresponding to required travel time and route extraction means. In-vehicle navigation system. 7. The route extraction means calculates the required distance for each route. Calculate the travel time and compare the required travel times. It compares and extracts the shortest route. A vehicle according to claim 6 above Onboard navigation system. 8. The route search method is between the current location and the destination Set the route search range based on the straight line distance of The scope of the above claims is limited. In-vehicle navigation system described in paragraph 6 Tem. 9. when the second storage means runs at a predetermined point in time; represents the required travel time for a road segment. a storage medium storing data to be Increase/decrease in required travel time for each guided route run It consists of a storage medium that stores Vehicle-mounted type according to claim 6 above navigation system. 10. 10. The in-vehicle navigation system according to claim 9, wherein the data representing the required travel time of a road segment is set for each month, day of the week, and time zone. 11. 7. The vehicle-mounted navigation system according to claim 6, wherein the road data acquisition means is a wireless device. 12. 7. The in-vehicle navigation system according to claim 6, wherein the second storage means is a removable RAM, and information regarding the required travel time of the road segment is loaded from the outside. 13. 7. The in-vehicle navigation system according to claim 6, wherein the new data storage means stores an increase/decrease in the required travel time of the road segment stored in the second storage means.