JP2996074B2 - Route calculation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads out road map data in a range including a current position and a destination of a vehicle from a road map memory in accordance with setting of a destination and the like by a driver, and based on the road map data. The present invention relates to a route calculation device which can calculate an optimum route to a destination and show it to a driver.

[0002]

2. Description of the Related Art Conventionally, there has been known a navigation device developed to display the position and orientation of a vehicle on a screen and to facilitate traveling on an unknown land or at night.
The navigation device is equipped with a display, a direction sensor, a distance sensor, a road map memory, and a computer (including a locator (position detection device)) in a vehicle, and the direction data input from the direction sensor and the traveling input from the distance sensor. The vehicle position is detected by the locator based on the distance data and the road pattern stored in the road map memory, and the vehicle position is displayed on a display together with the road map.

In this case, in order to select a traveling route from a current position to a destination, a method is used in which a computer automatically calculates a route from the current position of the vehicle to the destination according to a driver's setting input of the destination. (See Japanese Patent Application Laid-Open No. 5-53504). In this method, the road to be calculated is divided into several parts, and the divided points are used as nodes,
A path connecting the nodes is a link, a node or link near the current location (or destination) is a departure node or link, and a node or link near the destination (or current location) is a destination node or link. The road map data stored in the road map memory between them is read out, transferred to the work area, all the link trees are searched in the work area, and the link costs of the routes constituting the tree are sequentially added to Only the path with the lowest link cost that reaches the node or link is selected.

[0004] If a route is calculated in this way and the vehicle is driven along the route, the vehicle will surely reach the destination, which is convenient for a driver who does not know the road.

[0005]

In the above route calculation, when a departure node or a link or a destination node or a link (hereinafter, a link is assumed) is recognized, the detected current position of the vehicle is determined. One or a plurality of links whose distances are close to each other are selected (JP-A-2-277200,
See JP-A-4-88600).

However, for example, when an expressway and a general road are installed close to each other, the link corresponding to the expressway is different from the link corresponding to the general road in the route calculation. Depending on whether a road is chosen, the result of the calculation will be quite different. In other words, if the expressway link is selected as the departure point link while driving on a general road, and the current location and the destination are so close that there is no need to use the expressway, the optimal route is the next interchange of the expressway. Then, it will be a route that gets down to the general road and returns to the destination,
The driver is confused. Conversely, if the general road link is selected as the departure point link while driving on the highway and the current location and the destination are far enough to use the highway, the optimal route is the next interchange on the highway. The driver will be confused at this time because the route will follow a general road up to the highway and proceed toward the destination.

Of course, the locator detects the current position of the vehicle based on the coincidence with the road pattern stored in the road map memory as described above. It is conceivable that the current location information of the vehicle obtained from the locator includes a distinction as to whether the vehicle is currently traveling on an expressway or a general road. However, the road map data for position detection and the road map data for route calculation are usually completely different data depending on the use of the map.

More specifically, for the purpose of detecting the position of a vehicle, the road map data includes fine roads and has a short link length in order to accurately detect the position. Does not include a fine road because it is not a calculation target up to a living road, and has a long link length because a plurality of links are connected to form a single link. Furthermore, there is no guarantee that the road type in the road map data for position detection and the road type in the road map data for route calculation are the same. For example, in the road map data for position detection, the motorway is a type of expressway, but in the road map data for route calculation, it may be treated as a general road instead of an expressway.

Therefore, in calculating the route, it does not make much sense to distinguish whether the vehicle is running on a highway or a general road in the current location information of the vehicle obtained from the locator. Is the current situation. Therefore, when calculating the route, the type of the departure point link must be determined based only on the current position information of the vehicle obtained from the locator.

Therefore, it is conceivable that the driver knows whether he or she is currently traveling on a highway or a general road, and to artificially input the driver (Japanese Patent Application No. Hei 5-79824). According to this artificial input method, even if the expressway and the general road are installed in parallel, a correct link can be obtained with certainty in the route calculation. Then, the type of road must be displayed in characters and one of them can be selected with a touch key, or a road map is called up, and a plurality of routes must be color-coded and one of them can be selected with a touch key.

[0011] For this reason, complicated and complicated procedures are required for the driver while traveling, and a traffic safety problem remains. Therefore, an object of the present invention is to specify a route calculation link or node near the current location without selecting a road link or node of a type different from the driver's intention. It is another object of the present invention to provide a route calculation device in which an input method by a driver is further improved.

[0012]

SUMMARY OF THE INVENTION A route calculation device according to the present invention includes at least a route map data for route calculation.
The types of the expressway link and the general road link are stored, and a highway link or a general road link can be set as one or both end points of the route calculation. Further, there is provided a key input unit which can manually input a recalculation request signal with one touch by exchanging a link type which is one or both end points of the route calculation during or after the calculation of the optimum route by the route calculation unit. ing.

Therefore, when the recalculation request signal is input by the key input means, if the road type previously set by the road type setting means is an expressway, the general road link is recognized, and If the road type set by the setting means is a general road, the highway link can be recognized and the optimum route can be recalculated. As described above, first, a route is calculated by setting an expressway or a general road as one or both end points of the route calculation, and if the driver setting is incorrect or the situation changes during the calculation, With one touch, the road type can be changed and the recalculation request signal can be manually input, so the driver can
During traveling, an optimal route can be obtained by starting or ending with a road of the type desired by the driver without calling a menu screen or calling a road map.

In the route calculation device according to the second aspect,
The road type setting means can set a highway link or a general road link as a link close to the current position which is one end of the route calculation, and the key input means, during the calculation of the optimal route by the route calculation means The user can manually input the recalculation request signal with one touch by exchanging the type of link near the current location.

As described above, only the link on the current location side is set as an expressway link or a general road link, and the type of the link on the destination side cannot be set. This is because fixing to a road or a general road is practically acceptable (normally, it will be fixed to a general road). In the route calculation device according to the fourth aspect, the road type setting unit automatically sets a general road link when a road calculation request signal is input by the calculation request unit without setting the road type on the display screen. Things.

As described above, if there is no manual setting action, the general road is prioritized as the current location side of the route calculation because the road selected as the starting point of the route calculation is overwhelmingly a general road. is there. If the driver is driving on a highway, the route is calculated without setting the type of road on the display screen, and during the calculation, the type of departure road is changed to the highway with a single touch and recalculated. Since the request signal can be manually input, traffic safety can be improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a block diagram illustrating a configuration of the navigation device including the route calculation device. This navigation device is mounted on a vehicle and used to support the traveling of the vehicle. This device is
A GPS receiver 5 is provided as a direction sensor, and an engine control unit (ECU) 6 is provided as a vehicle speed sensor.
The vehicle speed signal is obtained. These detection outputs are provided to the vehicle position detection unit 14.

The vehicle position detecting section 14 detects the azimuth information detected by the GPS receiver 5, the position information based on the vehicle speed signal,
The vehicle position is calculated based on a comparison with a road pattern stored in the map-dedicated disk D (so-called map matching method, see JP-A-64-53112). This calculation is
Since the vehicle position information is updated at regular intervals (for example, 1.2 seconds), the vehicle position information is updated at this interval as the vehicle travels.

Data representing the current position of the vehicle detected by the vehicle position detector 14 is provided to a controller 16 in the navigation device main body 1. The controller 16
The control center of the navigation device main body 1 functions as a load unit, a link recognition unit, and a route calculation unit. The controller 16 includes a CPU 161, an SRAM 162, a D
It includes a RAM 163 and the like. The controller 16
Is connected to a memory control unit 11, a display control unit 12, an input control unit 13, and a voice control unit 15 provided in the navigation navigation device body 1 through a bus in the navigation device body 1.

The display control unit 12 is connected to the liquid crystal display 3 provided in the vehicle. The input control unit 13 is connected to a remote control key 4 having a plurality of mechanical switches. The remote control key 4 is used for inputting a destination and requesting a route calculation, as well as a road type setting means for setting whether a vehicle departs from an expressway or a general road as a starting point of the route calculation, and a route calculation means. During the calculation of the optimum route, the type of the departure road is exchanged, and the re-calculation request signal can be manually input with one touch. The remote control key 4 has many keys as shown in FIG. The names and functions of the main keys are as follows.

(1) Joystick set key: A key for scrolling a map, setting a position, and selecting a menu. The joystick can be tilted in eight directions, and the set key can be pressed. To set whether the vehicle departs from an expressway or a general road as a starting point of the route calculation, this key is operated using a menu screen.

(2) Map key: When this key is pressed, a road map screen is displayed centering on the car mark. (3) Scale key: A key for scaling the display scale of the road map. (4) Rotation key: A key for selecting whether to display the traveling direction of the vehicle at the top or the north of the map at the top.

(5) Trajectory key: a key for switching whether or not to display the traveling locus of the vehicle. (6) Route key: A key pressed to calculate the optimal route from the current location to the destination. This key does not allow you to set whether the vehicle will depart from an expressway or an ordinary road as the starting point for route calculation, but if you press this key during route calculation, the calculation will be interrupted and The link can be changed to a highway departure point link and recalculated.

(7) Return key: A key for returning to the previous screen when operating a menu. (8) Menu key: A key for displaying a menu screen such as “destination setting” and “route setting”. The memory control unit 11 controls the CD drive 2. The CD drive 2 reads road map data and the like corresponding to the current position, destination, and intermediate area of the vehicle from the pre-loaded map-dedicated disk D in response to a control signal given from the memory control unit 11, and performs memory control. Part 11
Output to

The road map data includes road map data for vehicle position detection, road map data for display, road map data for route calculation, and road map data for intersection guidance. Here, a description will be given of road map data for route calculation related to the embodiment of the present invention. The road map data for route calculation is obtained by dividing a road map (including highway national roads, motorways, other national roads, prefectural roads, city roads in designated cities, and other living roads) into meshes, and A route composed of a combination of nodes and links in units is stored separately for an expressway / national road map, a general road map, and a detailed map. Highway / National Highway Map (hereinafter referred to as “Third Tier”
) Mainly include expressways (expressway national roads) and national roads (motorways and other national roads). General road correspondence maps (hereinafter referred to as “second layer”) include general roads (expressways and national roads). Road width of 5.5 m or more). Detailed maps (hereinafter referred to as "tier 1")
It includes not only general roads such as national roads but also domestic roads (road width of 3.3 m or more). Due to the characteristics of the road map database, a closed network is formed nationwide for roads higher than national roads.

[0026] The mesh is used to map a Japanese road map with a longitude difference of one.
The upper mesh corresponding to the third layer, which is divided by degrees and latitude difference of 40 minutes and the vertical and horizontal distance is about 80 km x 80 km, and the second upper mesh is divided into 8 vertical and horizontal distances and the vertical and horizontal distance is about 10 km x 10 km It has a triple structure of a middle mesh corresponding to the layer and a lower mesh corresponding to the first layer in which the middle mesh is equally divided vertically and horizontally into a vertical and horizontal distance of about 1 km × 1 km.

A node is generally a coordinate position for specifying an intersection or a turning point on a road. A node indicating an intersection is an intersection node, and a node indicating a turning point (excluding an intersection) on a road is a node. It is called an interpolation point node. The link connects the start point node and the end point node, and can be understood as a directional polygonal line that follows the shape of the road (see FIG. 4A). As shown in FIG. 4A, data in which the coordinates of the nodes constituting the links are stored one by one is called link shape data, and this link is called a shape link or simply a link. Ignoring the shape of the broken line, data obtained by compressing and storing cost (passing time and distance) information when passing through a link and information indicating a connection state with another compressed link are referred to as link compressed data. The link stored by compression is referred to as a compressed link (see FIG. 4B). The link compressed data is useful for shortening the calculation time when calculating the route.

Here, the storage structure of the route calculation road map data will be described with reference to FIG. The route calculation road map data has an upper mesh pointer file, an address file, a third layer link compression data, and a third layer acquisition file below the memory management unit. Further, it has second-layer link shape data and second-layer link compressed data whose addresses are managed by an address file.

The upper mesh pointer file has data for confirming whether or not the second layer link shape data exists around a certain point, and size data of each mesh of the second layer link compressed data. . The third layer acquisition file contains information on the extent to which the third layer link compressed data should be acquired according to the current location and the point of departure, and the intermediate mesh to which the current location belongs and the departure location. It has for each combination of the middle mesh to which it belongs.

The second layer link shape data includes, for each shape link constituting the second layer, coordinates of a start node, an end node, and an interpolation point node, a pointer to a compressed link corresponding to the shape link, and Have traffic information.
The layer 2 and layer 3 link compressed data stores compressed link information for route calculation, and the road type of the layer 2 and layer 3 compressed link (highway expressway, motorway, other ), A link cost, a link length, a pointer to another compressed link connected to the compressed link, a connection cost, and the like.

Here, the link cost is a time expressed in, for example, seconds when the vehicle runs on the compressed link. Actually, link cost changes due to traffic congestion, etc.
Here, the cost of driving at the legal speed is used. The connection cost is the sum of the cost of turning right or left or going straight to exit the compression link and enter the next compression link. For example,
In the case of entry prohibition, the connection cost is infinite, and if there is a traffic light, the cost is considered in consideration of the average signal waiting time when turning right or left or going straight.

The link cost and the connection cost can be changed in consideration of, for example, traffic congestion information on the road through a beacon receiver. Also, the driver can change the cost according to his / her preference. For example, the cost can be increased or decreased only for a specific type of road (highway). The controller 16 determines the optimum position from the current position to the destination based on the current position data detected by the vehicle position detection unit 14, the destination data input from the remote control key 4, and the road map data supplied from the memory control unit 11. Calculate the route (described below). Then, a road map, a vehicle current position mark on the map, and a line (dashed line, dotted line, etc.) along the optimal route are generated, and the liquid crystal display 3 is displayed through the display control unit 12.
To be displayed.

Here, among the menu screens, a route setting screen, which is a screen related to the present invention, will be described with reference to FIG. The route setting screen is one of menu screens, and is displayed for setting various route calculation conditions at the time of route calculation. Here, the route calculation condition means whether to give priority to a toll road, whether to use a ferry, whether to set a stopover, whether to set the road type of the departure point to an expressway or a general road. Each is manually set with the joystick set key while the route setting screen is displayed. If you issue a route calculation command without setting anything with the joystick set key, or if you issue a route calculation command by operating the route key, priority is given to toll roads, ferry is used, and stopovers are set. Instead, the setting is made automatically so that the starting point is a general road. This is for setting the most frequently set contents.

Another screen deeply related to the present invention is a screen displayed during route calculation. In this screen, as shown in FIG. 1, a timer is displayed, and furthermore, characters "Please press a route key on an expressway" are displayed. The timer indicates the time until the end of route calculation, and the character display asks whether to re-recognize the departure point link and recalculate if the current location is on a highway instead of a general road during route calculation. Things.

The controller 16 includes a vehicle position detector 14
Of the links near the current location of the vehicle input from, the link corresponding to the type of road set on the route setting screen etc. is set as the departure point link, the link near the destination is set as the destination link, Searching the tree of all links to the destination link (or vice versa), sequentially adding the link costs of the routes that make up the tree, and selecting only the route with the lowest link cost to reach the destination. So-called potential method (Kobayashi et al. "Navigation system with recommended route display function" Sumitomo Electric No. 141,
PP.155-160, September 1992).

As a work area for executing the potential method, the controller 16 of the navigation device body 1 is used.
Provides a buffer area on the DRAM 163. The DRAM 163 has a current location recognition flag that is set according to whether the departure point link is selected from an expressway or a general road, and whether the destination link is selected from an expressway or a general road. There is a destination recognition flag that is set accordingly. However, the destination link is selected from general roads for the reason described later, and therefore, the destination recognition flag is always set to “general road”.

FIG. 7-9 is a flowchart showing a control procedure when the route from the current position to the destination is calculated in the navigation device of this embodiment. 7 and 8 show the previous stage of the processing according to the present invention. As the order of the description, the processing will be described first with reference to FIGS. 7 and 8, and then the processing of the present invention will be described with reference to FIG. I will explain.

When the current position data of the vehicle is input from the vehicle position detecting unit 14 during traveling (step S1), the memory control unit 11 determines whether it is necessary to update the link shape data of the middle mesh including the current position. Is determined (step S2). Since the departure point link in the route calculation performed in step S35 changes when the vehicle moves, the link shape data of the intermediate mesh is updated to obtain a new departure point link. The method of obtaining the departure point link will be described later. Step S1
The process of -S2 is repeated at regular intervals (for example, 1.2 seconds) at which the current position data of the vehicle is updated.

If it is necessary to update the data, new link shape data (for four meshes around the vehicle) is read and DR
It is stored in a predetermined area of the AM 163 (step S3). Next, it is determined whether or not to update the second layer link compressed data (step S4). This criterion is as follows. FIG. 10 is a second layer map around the current position of the vehicle, and each square represents a medium mesh. The current position of the vehicle is represented by _Pn , and the position of the vehicle one cycle before is represented by _{Pn - 1} . When the position of the vehicle is at P _n−1 , the thick frame W
The link compressed data of 9 meshes surrounded by _n-1 is D
It is stored in a predetermined area of the RAM 163. In the next cycle, the position of the vehicle is in the adjacent median mesh P _n, 9 sheets of mesh surrounded by thick frame W _n is a region of "current position near", the second layer data in this area update Need to be done. Therefore, it is necessary to newly acquire data relating to the middle mesh B ₁ -B ₅ and release data relating to the middle mesh C ₁ -C ₅ . As described above, when it is necessary to acquire and release the compressed data, it is determined that the entire second layer link compressed data needs to be updated.

If it is determined that the file needs to be updated, the upper mesh pointer file is read (step S).
5). The reason for reading the upper mesh pointer is to estimate the data size of each mesh of the second layer link compressed data around the current location. Next, the empty size of the predetermined area of the DRAM 163 is confirmed, and this size is set to A (step S6).

Then, the size of the second layer to be obtained is estimated by the upper mesh pointer, and
(Step S7). Also, the second to release
The size of the layer is estimated by the upper mesh pointer, and this is set as C (step S8). Then, it is determined that A + CB> 0 (1) (step S9). If the equation (1) does not hold, the low-priority link data is dropped from the link compressed data (step S10). This operation means giving up acquisition of all or a part of the mesh data on the side opposite to the destination direction, for example, based on the position of the vehicle.

If the expression (1) is satisfied, the second layer link compressed data of the medium mesh of nine (or less if step S10 is applied) near the current position is obtained, and the predetermined data in the DRAM 163 is obtained. (Step S
11). Next, the process proceeds to step S21 in FIG. 8, and it is checked whether or not the driver has set a destination (step S21). This setting is performed using the joystick set key on the menu screen of “destination setting”.
If there is a destination setting, the second layer link shape data (for four medium-level meshes around the destination) is read out (step S2).
2), read the upper mesh pointer file (step S23), check the free size of the predetermined area of the DRAM 163, set this size to A (step S24), and set the size of the second layer to be acquired to the upper mesh pointer. And estimate this as B (step S2
5) It is determined whether AB> 0 (2) (step S26). The reason for not estimating the size of the second layer to be released is that the destination setting is not repeated at regular intervals like the current location input, but once set, it is held as it is until the route calculation ends, This is because everything is erased when finished.

If the equation (2) does not hold, the low priority data is dropped from the link compressed data (step S27). This operation refers to, for example, giving up acquisition of all or a part of the mesh data on the opposite side to the current location direction based on the position of the vehicle. If the equation (2) is satisfied, the 9th layer (the smaller number when step S27 is applied) medium-level mesh second-layer link compressed data near the destination is read out, and a predetermined area of the DRAM 163 is read out. It is stored (step S28).

During the acquisition of the second-layer link compressed data and the like, the driver performs the above-mentioned "route setting".
In the menu screen of (1), calculation conditions for making a route calculation request can be set (step S29).
As described above, the calculation conditions include whether to give priority to a toll road, whether to use a ferry, whether to set a stopover, and whether to set a departure point on an expressway or a general road.

Next, it is confirmed whether or not there is a route calculation request from the driver (step S30). This route calculation request may be made using the route key or by calling a menu screen. If there is a request, go to FIG. First, it is confirmed whether or not there is a setting as to whether the departure point should be an expressway or a general road (step S3).
2). If there is no setting, it is regarded that a general road has been set (step S33), and processing is performed.

Then, the "route calculation in progress" screen of FIG. 1 is displayed (step S34). During this display, the controller 16 uses the previously read link shape data around the current location and the link shape data around the destination to read the departure link near the current location and the destination link near the destination. , And if necessary, reads out the third layer link compressed data existing in the middle of the current destination, and uses the second layer link compressed data and the third layer link compressed data to connect the departure link and the destination link. The optimum route for traveling between the roads is calculated and displayed (step S35).

However, when recognizing the departure point link, the controller 16 determines the optimum departure point link and destination according to whether the departure point set in step S29 is to be an expressway or a general road. Searching for a land link is one feature. Hereinafter, step S35
Will be described in more detail.

FIGS. 11 and 12 are flowcharts detailing the contents of step S35. First, the method of the route calculation instruction is determined (step S41). If the route calculation command has been issued using the menu screen, step S29
It is determined whether the departure point set in the above is on an expressway or a general road (step S42). If the departure point is on an expressway, the current position recognition flag is set to "high speed" (step S44). The flag is set to "general" (step S45). If the route calculation command has been issued using the route key, it is determined whether the destination has already been set on the menu screen (step S43). If the destination has not been set, an error message is displayed and the processing ends. If the destination has been set, the current location recognition flag is set to "general" (step S45). The reason for setting to "general" is that it is unlikely that starting from the expressway is usually possible except when driving on the expressway, and for the average driver, traveling on the expressway will not Because it's far less time.

After the current location recognition flag is set, an optimal nearest link, that is, a departure location link is determined using the link shape data near the current location according to whether the departure point is an expressway or a general road. Recognize (Step S4)
7). Details of this recognition processing will be described later. During this time, it is checked whether the root key has been pressed on the screen of FIG. 1 (step S48). The reason for checking is to confirm the driver's request to interrupt the calculation, change the departure point link to a departure point link of another road type, and recalculate. Such a request may be made when the driver should set the departure point to the expressway on the route setting menu screen (FIG. 6), but did not make a mistake, or because the driver issued a route calculation command using the route key. This occurs when the setting cannot be made or when the driver wants to calculate the route again after entering the expressway from the general road.

When the root key is pressed, the content of the current location recognition flag is changed from "general" to "high speed" (step S46), and the process returns to step S47. If the route key has not been pressed, the destination recognition flag is set to "general" (step S49), and the destination link of the general road is recognized using the link shape data near the destination (step S50). The reason for limiting to a general road is that it is impossible to set a point on the highway as a destination unless it is also a highway patrol or highway maintenance.

Then, as in step S48, it is checked whether or not the root key has been pressed on the screen of FIG. 1 (step S51). If the root key has been pressed, the content of the current location recognition flag is changed from "general" to "high speed". (Step S46), and the process returns to Step S47. If the root key has not been pressed, the flow advances to step S61 in FIG. 12 to read the third-layer link compressed data in the intermediate area.
When the third-layer link compressed data is required, for example, when the current location is far from the destination and a highway is used, the third-layer link compressed data is read. However, if the current location and the destination are close to each other and there is no need to use a highway or the like, there is no need to read the third-layer link compressed data in the intermediate area.

Then, a route is calculated between the departure point link and the destination link (step S62), and optimum route display data as a calculation result is created (step S64).
It is displayed on the road map (step S65). During the route calculation, it is checked whether or not the root key has been pressed on the screen of FIG. 1 as in step S48 (step S63). The reason for this is to confirm the driver's request to interrupt the calculation, change the departure point link to a departure point link of another road type, and recalculate, as described above. However, in this case, since the route calculation process has been started, a part of the road map data stored in the buffer area on the DRAM 163 has been processed and modified. Therefore, without reusing the road map data, these road map data are deleted once, and the map data (link shape data and link compressed data) near the current position and the destination are read out again (step S66), and return to step S46.

Next, the nearest link recognition process (step S)
47, 50) will be described in detail. FIGS. 13 and 14 are flowcharts for explaining the nearest link recognition processing. Explaining along the flow of the figure, a variable called “link distance” for finding the nearest link is introduced for each of the expressway and the general road. The link distance for expressways is L ₁ and the link distance for general roads is L ₂ . First, each link distance is set to a sufficiently large value (step S71).

Then, a map within a predetermined range is searched (step S72), a shape link is taken out of the map (step S73), and a distance d from the current position to the shape link is calculated (step S74). The map of the predetermined range in step S72 refers to, for example, the following range. That is, the middle mesh 4 around the current location read in step S3
If it is the number of sheets, it will be included in a distant place unnecessary for the nearest link recognition. Therefore, one middle mesh is divided into 16 sections, and 4 sections (referred to as one block) including the current position are set as a search range. FIG. 15 illustrates one block including the current position by dividing one medium-level mesh into 16 sections. If the current position is among the threshold lines represented by dotted lines, the block surrounding the threshold line 1 The block becomes the search range. Therefore, if the current position is at the end of the middle mesh, one block including the other middle meshes is taken.

An example of a method of calculating the distance d in step S74 will be described. An arbitrary pair (two points) is selected from the starting point, the ending point, and the interpolation point of the shape link, and the distance between the current position and the two points is d _1. , D ₂ . FIG. 16 shows an example in which distances d ₁ and d ₂ are taken between the interpolation points a and b. If any of these distances d ₁ and d ₂ is smaller than the upper limit value, the vertical distance between the straight line connecting the interpolation points a and b and the current position is calculated (see FIG. 17). Further, for the same shape link, any two points are selected from the pair of the remaining start point, end point, and interpolation point, compared with the upper limit value, and if smaller than the upper limit value, the same processing as above is performed to calculate the vertical distance. . If the vertical distances can be calculated for all pairs of one shape link, they are compared with each other, and the shortest vertical distance is set as the distance d between the current location and the shape link.

Next, the process proceeds to step S75, where it is determined whether the shape link is a highway link or a general road link.
If it is a highway link, it is determined whether or not the distance d is smaller than a threshold value (a link search range; for example, 200 m) (step S76). This determination is to find only links near the current location. If the distance is smaller than the threshold value, the distance d is the highway link distance L _1.
It is determined whether it is smaller than (Step S78). Since the motorway link distance L ₁ initially is set to a sufficiently large value, it is determined that "YES", the process proceeds to step S80. In step S80, it substitutes the value of the distance d to the motorway link distance L _1. Then, the link number and mesh code of the shape link are registered (step S8).
2).

If it is determined in step S75 that the link is a general road link, it is determined whether the distance d is smaller than the threshold (step S77). Smaller than the threshold value, the distance d is determined whether a general road link distance L ₂ is smaller than (step S79). Since the general road link distance L ₂ initially is set to a sufficiently large value, it is determined that "YES", the process proceeds to step S81. At step S81, it substitutes the value of the distance d to the general road link distance L _2. Then, the link number and mesh code of the shape link are registered (step S83).

Then, returning to step S72, it is determined whether or not all the shape links belonging to the search range of one block have been searched. If not all the shape links have been searched, the processing from step S73 is repeated. At this time, since the highway link distance L ₁ and the general road link distance L ₂ are used as variables, finally, the nearest links corresponding to the highway and the general road, if any, are found. Will be.

[0059] At step S81, motorway link distance L _1, by examining the general road link distance L _2, determines whether or nearest neighbor link corresponding to each of the highway and the general road is found. If not found, in step S82, the link search range is changed to, for example, 800 m (step S83),
Search for the nearest link again. If it is not found even after searching at 800 m, error processing is performed.

If the nearest link is found, the flow advances to step S91 in FIG. In step S91, the link recognition flag is checked to determine whether an expressway or a general road has been selected as the departure point link. If a highway has been selected, it is checked in step S92 whether the nearest link corresponding to the highway has been registered.
If "YES", the link number and the mesh code of the nearest link are output (step S96). If the nearest link corresponding to the highway is not registered,
It is checked whether the nearest link corresponding to the general road is registered, and if "YES", the link number and the mesh code of this nearest link are output (step S).
97). Similar processing is performed when a general road is selected (steps S93 and S95). Thus, high speed (general)
If no nearest link is registered for the road,
The output of the nearest link corresponding to a general (highway) road is a two-stage configuration. Even if a route cannot be calculated from the type of road requested by the driver, as a next best measure, the other type is used. This is because the route can be calculated from the road.

The above-described processing for recognizing the nearest link in FIGS. 13 and 14 is applied not only when searching for the departure point link on the current location side, but also when searching for the destination link on the destination side. Things. However, in this case, since no expressway is specified, a destination link is searched for from general road links. As described above, the route calculation can be performed with the nearest link corresponding to the type of road requested by the driver as the departure point link and the nearest link corresponding to the general road as the destination link. Furthermore, if there is a request to interrupt the calculation, change the departure point link to a departure point link of another road type, and recalculate, for example, during the calculation of the optimum route by the route calculation means, one-touch using the route key. Recalculation can be performed by manually inputting a recalculation request signal (steps S48, 51, 63).
Therefore, the driver can safely and quickly calculate the re-route from the desired type of road as a starting point without calling the menu screen or calling the road map during driving.

[0062]

As described above, according to the present invention, first,
The route is calculated by setting the expressway or general road as one or both end points of the route calculation, and if the driver setting is incorrect or the situation changes during the calculation, one-touch, road type Is exchanged, and a recalculation request signal can be manually input, so that it is possible to prevent a situation where a route is calculated based on a type of road different from the driver's intention. Further, the driver does not need to call the menu screen or the road map during traveling, so that the optimum route can be obtained safely.

[Brief description of the drawings]

FIG. 1 is a diagram showing a screen during a route calculation.

FIG. 2 is a block diagram showing a configuration of a navigation device according to one embodiment of the present invention.

FIG. 3 is a front view of a remote control key.

FIG. 4 (a) is an illustrative view showing a shape link which is a polygonal line with a direction along the shape of a road, and FIG. 4 (b) is an illustration showing a compressed link used only for route calculation ignoring the polygonal line shape. FIG.

FIG. 5 is a diagram illustrating a storage structure of road map data for route calculation.

FIG. 6 is a diagram showing a route setting screen which is one of menu screens.

FIG. 7 is a flowchart for explaining a route calculation processing procedure according to an embodiment of the present invention;

FIG. 8 is a flowchart (continued from FIG. 7) for explaining a route calculation processing procedure according to an embodiment of the present invention;

FIG. 9 is a flowchart (continuation of FIG. 8) for explaining a route calculation processing procedure according to an embodiment of the present invention;

FIG. 10 is a second layer map around the current location of the vehicle.

FIG. 11 is a flowchart detailing the contents of a link recognition process.

FIG. 12 is a flowchart (continued from FIG. 11) detailing the content of the link recognition process.

FIG. 13 is a flowchart detailing the content of a nearest link search process.

FIG. 14 is a flowchart (continuation of FIG. 13) detailing the content of the nearest link search process.

FIG. 15 is a diagram showing a state in which one medium mesh is divided into 16 blocks and 4 blocks.

FIG. 16 is a diagram illustrating a positional relationship between a current position and interpolation points a and b of a shape link.

FIG. 17 is a diagram showing a vertical distance between a straight line connecting interpolation points a and b and a current position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Navigation apparatus main body 2 CD drive 3 Display 4 Remote control key 5 GPS receiver 6 ECU 11 Memory control unit 12 Display control unit 13 Input processing unit 14 Vehicle position detection unit 16 Controller 161 CPU 163 DRAM D Map dedicated disk

Continuation of the front page (56) References JP-A-5-240652 (JP, A) JP-A-1-198998 (JP, A) JP-A-4-232812 (JP, A) JP-A-4-152383 (JP) JP-A-3-194417 (JP, A) JP-A-6-314301 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G08G 1/0969 G01C 21/00 G09B 29/10

Claims (4)

(57) [Claims] 1. A position detecting means for obtaining a current position of a vehicle based on signals from various sensors, a road map storing means for storing road map data for route calculation, and a destination input for inputting a destination. Means, calculation request means for inputting a route calculation request signal, current position data of the vehicle input from the position detection means, and destination data input from the destination input means, stored in the road map storage means. Loading means for reading the road map data in the predetermined range and storing it in the work area; and when a route calculation request signal is input from the calculation request means, reads each road map data stored in the work area to read the current location and Link recognizing means for recognizing links close to the destination, and using the road map data stored in the work area to determine the current location and the destination. A route calculation device that calculates an optimal route when traveling between links that are close to each other, wherein the road map storage unit determines at least the type of the highway link and the general road link of the road map data. And a road type setting means for setting a highway link or a general road link as one or both end points of the route calculation, wherein the link recognizing means recognizes the road when recognizing the link. According to the setting contents of the type setting means, the information is recognized from either the highway link or the general road link. Further, during or after the calculation of the optimum route by the route calculating means, one of the route calculation or It comprises key input means that can manually input a recalculation request signal with one touch by exchanging the link types that are both end points, The link recognizing means recognizes a general road link if the road type previously set by the road type setting means is an expressway when the recalculation request signal is input by the key input means, and If the road type set by the setting unit is a general road, the route calculating device recognizes the highway link and resupplies the expressway link to the route calculating unit. 2. The road type setting means is capable of setting an expressway link or a general road link only as a link near the current position which is one end of the route calculation. 2. The route calculation device according to claim 1, wherein during the calculation of the optimum route, the type of the link close to the current location is exchanged, and the recalculation request signal can be manually input with one touch. 3. The route calculation device according to claim 1, wherein the input of the calculation condition by the road type setting means is performed on a display screen attached to the route calculation device. 4. The road type setting means automatically sets a general road link when a route calculation request signal is input by a calculation request means without setting a road type on a display screen. 3. The route calculation device according to 3.