JPH07113653A - Path computer - Google Patents

Abstract

PURPOSE:To start the computing of a path by simple operation by providing a key input means capable of inputting a computing requirement signal by single operation, anew recognizing a current spot and a near link by using road map data in the vicinity of the current spot of a car stored in a working area and computing the path. CONSTITUTION:A car-position detecting section 14 computes the position of a car on the basis of azimuth information detected by a GPS receiver 5 and positional information based on a car speed signal, etc. Data displaying the detected 14 current spot of the car are transmitted over a controller 16 in a navigation device body 1. The controller 16 is connected to a memory control section 11, a display control section 12, an input control section 13 and a voice control section 15 through a bus in the main body 1. The control section 13 is connected to a remote control key 4 enabling a single operation input. When the key 4 is worked by single operation during the computing of an optimum path or after the computing, the path can be calculated between the current spot and a link near to a destination previously specified as the near link.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reads road map data in a range including a starting point and a destination from a road map memory according to the setting of a destination by a driver, and based on the road map data. The present invention relates to a route calculation device capable of calculating an optimum route to a destination and showing 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 a strange land or at night.
The navigation device has a display, an orientation sensor, a distance sensor, a road map memory, and a computer (including a locator (position detection device)) mounted on a vehicle, and the orientation data input from the orientation sensor and the travel 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 this vehicle position is displayed on the display together with the road map.

In this case, in order to select a traveling route from the starting point to the destination, the route from the current position of the vehicle to the destination is automatically calculated by the computer according to the setting input of the destination by the driver. A method has been proposed (see JP-A-5-53504). This method divides the roads to be calculated into a number of points, and defines the points as nodes.
A route connecting a node and a node is a link, a node or link close to a starting point (may be a destination) is a starting point node or link, and a node or link near a destination (may be a starting point) is a destination node or As a link, read the road map data stored in the road map memory between them and move it to the work area, search all the tree of links in the work area, sequentially add the link costs of the routes that make up the tree, Select only the route with the lowest link cost to reach the destination node or link.

The calculation procedure according to the above calculation method will be described below. First, the current location of the vehicle is recognized.
This is possible by repeatedly detecting the vehicle position with the above-mentioned locator. Next, a driver who wants to calculate a route inputs a route calculation condition such as a destination and issues a route calculation command. Then, the computer acquires the road map data around the current location and the road map data around the destination, and if necessary, the road map data of the intermediate area between the current location and the destination, and performs route search processing (potential processing). .

This method is convenient for a driver who does not know the route because the route can be reliably calculated by calculating the route and traveling along the route. By the way, in order to calculate the route by the above method, the driver must set the calculation condition for the route calculation. Here, the calculation conditions are where the destination is, whether to give priority to the toll road, whether to use the ferry, whether to set the waypoint, whether to set the departure point to the highway or the general road. And the like.

Conventionally, in order to set the calculation condition, a menu screen is displayed on the display of the navigation device and the touch key is touched to set the calculation condition.

[0007]

However, if a calculation condition needs to be set during traveling, for example, when traveling off the route calculated before traveling, the navigation If the calculation conditions are set by displaying the menu screen on the display of the device, the driver cannot concentrate on driving, which is not preferable in terms of traffic safety.

Therefore, the vehicle must be stopped and set, which leads to a loss of time and fuel, and also causes traffic congestion. The present invention has been made in view of the above problems, and provides a route calculation device capable of starting route calculation with a simple operation even when the setting of calculation conditions cannot be practically set, such as during traveling. To aim.

[0009]

A route calculation device of the present invention comprises key input means capable of inputting a calculation request signal with one touch, and during or after calculation of an optimum route.
When the calculation request signal is input by the key input means, the destination is stored in the work area on condition that the destination is input by the calculation condition input means for inputting various calculation conditions such as the destination. This is to calculate a route by newly recognizing a link close to the current position using road map data near the current position of the vehicle.

The route calculating device of the present invention is
The current location of the vehicle is repeatedly obtained based on the signals from various sensors, and based on the current location information of the vehicle as the vehicle travels,
It is preferable that the road map data in the vicinity of the present location to be stored in the work area is updated (claim 2). Further, the various calculation conditions input by the calculation condition input means include, in addition to the destination, whether to give priority to a toll road, whether to use a ferry, whether to set a waypoint, and the departure point to the highway. If the calculation request signal is input by the key input means, each calculation condition such as whether to use the general road or the general road is included, the calculation conditions are set as the previously set calculation conditions, It is preferable to calculate the route (claim 3).

In addition to the destination, various calculation conditions input by the calculation condition input means include whether to prioritize a toll road, whether to use a ferry, whether to set a waypoint, and a departure point. When the calculation request signal is input by the key input means, each calculation condition including whether the road is an expressway or an ordinary road is determined in advance except the destination. The route calculation may be limited to one of the two options (claim 4).

[0012]

According to the route calculation device, during the optimum route calculation,
Or after the calculation, if you operate the key input means with one touch,
At a minimum, provided that the destination has been entered, a new link close to the current location is newly recognized using the road map data near the current location of the vehicle stored in the work area. A route can be calculated with a link close to the specified destination.

Therefore, even when the calculation conditions cannot be set practically, such as during traveling, if the minimum destination is set, the return route can be calculated by a simple operation. Further, as claimed in claim 2, while traveling, the current position of the vehicle is repeatedly obtained based on signals from various sensors, and based on the current position information of the vehicle accompanying the traveling of the vehicle, a road map near the current position to be stored in the work area. If the data is updated, the road map data around the current position can always be immediately read and used, so that the route calculation time can be shortened.

Further, when the calculation request signal is inputted by the key input means as in claim 3, it is preferable that the route calculation condition is the same as the previously set calculation condition and the route calculation is performed. When calculating the return,
This is because the route calculation conditions are often the same as before.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of a navigation device including a route calculation device. This navigation device is mounted on a vehicle and is used for supporting the traveling of the vehicle. This device
A GPS receiver 5 is provided as a direction sensor, and an engine control unit (ECU) 6 is provided as a vehicle speed sensor.
I am trying to get the vehicle speed signal. These detection outputs are given to the vehicle position detection unit 14.

The vehicle position detecting section 14 includes azimuth information detected by the GPS receiver 5 and position information based on a vehicle speed signal.
The vehicle position is calculated based on comparison with a road pattern stored in the map-dedicated disk D (so-called map matching method, see Japanese Patent Laid-Open No. 64-53112). This calculation is
Since it is performed every fixed period (for example, 1.2 seconds), the vehicle position information is updated in this period as the vehicle travels.

The data representing the current position of the vehicle detected by the vehicle position detector 14 is given to the controller 16 in the navigation device body 1. The controller 16
It is a control center of the navigation device body 1 and functions as first and second loading means, a link recognition means, and a route calculation means. The controller 16 is a CPU 161, SRAM
162, DRAM 163 and the like. Further, 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 inside the vehicle. The input control unit 13 is connected to the remote control key 4 having a plurality of mechanical switches. The remote controller key 4 functions as a calculation condition input means for inputting various calculation conditions such as a destination and a key input means for inputting a calculation request signal 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: Scroll the map,
The joystick can be tilted in 8 directions and the set key can be pushed in with the keys for setting the position and selecting the menu. When setting various calculation conditions such as destination (whether toll road is prioritized, ferry is used, transit point is set, departure point is highway or general road, etc.) Is performed by operating this key using the 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 enlarging or reducing the display scale of the road map. (4) Rotation key: A key to select 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 to display the traveling trajectory of the vehicle. (6) Route key: A key that allows one-touch input of a calculation request signal when calculating the optimum route from the current location to the destination. If this key is pressed during the route calculation, the calculation can be interrupted, the departure point link can be changed if necessary, and the return calculation can be performed.

(7) Return key: A key for returning to the previous screen when operating the menu. (8) Menu key: Key to display the menu screen such as "Destination setting" and "Route setting". The memory control unit 11 controls the CD drive 2. In response to a control signal given from the memory control unit 11, the CD drive 2 reads road map data and the like corresponding to the vehicle present location, destination and intermediate area from the map-dedicated disk D loaded in advance, and controls the memory. Part 11
Is output to.

The road map data includes vehicle position detection road map data, display road map data, route calculation road map data, and intersection guidance road map data. Here, the route calculation road map data related to the implementation of the invention will be described. Road map data for route calculation divides a road map (including highway national roads, motorways, other national roads, prefectural roads, city roads of designated cities, and other living roads) into meshes, and each mesh A route consisting of a combination of a node and a link is stored separately for a highway / national road map, a general road map, and a detailed map. Maps for highways and national roads (hereinafter "third layer")
Mainly includes highways (highway national highways) and national highways (automobile expressways, other national highways), and general road correspondence maps (hereinafter referred to as "second layer") include highways and national highways. Road width 5.5m or more) is also included. The detailed map (hereinafter referred to as "first layer") is a highway,
It includes not only general roads such as national roads but also living roads (road width 3.3m or more). Due to the characteristics of the road map database, a closed network is formed nationwide for roads above national roads.

The mesh is a Japanese road map with a longitude difference of 1
The upper mesh corresponding to the third layer, which is divided by 40 degrees in latitude and latitude difference and the vertical and horizontal distances are about 80km x 80km, and the upper mesh is divided into 8 vertical and horizontal parts, and the vertical and horizontal distances are about 10km x 10km. It has a triple structure of a middle mesh corresponding to a layer and a lower mesh corresponding to the first layer in which the middle mesh is divided into 10 equal parts in length and width and the distance in length and width is about 1 km × 1 km.

A node is generally a coordinate position for identifying an intersection or a turning point of a road. A node representing the intersection is an intersection node, and a node representing a bending point (excluding the intersection) of the road. 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 polygonal line with a direction along the shape of the road (see FIG. 5 (a)). Data that stores the coordinates of the nodes that form a link as shown in FIG. 5A is called link shape data, and this link is called a shape link or simply a link. Ignoring the shape of this polygonal line, the cost (passage time or distance) information when passing through the link, and the data that is stored by compressing the information indicating the connection state with other compressed links are called link compressed data, The compressed and stored link is called a compressed link (see FIG. 5 (b)). This link compressed data is useful for reducing the calculation time when the route is calculated.

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

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 provides information about to what extent the third layer link compressed data should be acquired according to the current location and the departure location, and the middle mesh to which the current location belongs and the departure location. It has for each combination of medium meshes to which it belongs.

The second layer link shape data includes, for each shape link forming the second layer, coordinates of a start point node, an end point node, and an interpolation point node, and a pointer to a compression link corresponding to the shape link. It has the distinction of passage. The second-layer and third-layer link compression data store compression link information for route calculation, and are respectively stored in the second layer.
Type of the compression link of the 3rd and 3rd layers (Highway National Highway,
Motorways, other national roads,…), link costs,
The link length, pointers to other compressed links connected to the compressed link, connection cost, etc. are stored.

Here, the link cost is the time when the compressed link travels, expressed in seconds, for example. Actually, the link cost changes due to traffic congestion, etc.,
Here, the cost when traveling at the legal speed is used. The connection cost is the sum of right-and-left turn or straight-ahead costs for leaving the compression link and entering the next compression link. For example,
If entry is prohibited, the connection cost will be infinite, and if there is a signal, the cost will take into consideration the average signal waiting time when turning left or right or going straight.

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

Among the menu screens, the route setting screen, which is a screen related to the invention, will be described with reference to FIG. The route setting screen is one of the 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 the toll road, whether to use the ferry, whether to set a waypoint, whether the departure point is an expressway or an ordinary road. It is set with the joystick set key while the setting screen is displayed. If a route calculation command is issued without setting anything with the joystick set key, or if a route calculation command is issued by operating the route key, the toll road is prioritized, the ferry is used, and the route is set. Instead, the setting is automatically made so that the starting point is a general road. This is to set the most frequently set content.

The controller 16 includes a vehicle position detector 14
Of the links near the vehicle's current location input from, the link corresponding to the type of road set on the route setting screen is the departure link, the link near the destination is the destination link, and the destination link is the destination It searches all the trees of links that reach the destination link (or vice versa), sequentially adds the link costs of the routes that make up the tree, and selects only the route with the lowest link cost that reaches the destination. Potential method (Kobayashi et al. "Navigation system with recommended route display function" Sumitomo Electric No. 141, P
The optimum route is calculated using P.155-160, September 1992).

As a work area for executing this potential method, the controller 16 of the navigation apparatus body 1 is used.
Prepares 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 the expressway or the general road, and whether the destination link is selected from the highway or the general road. There is a destination recognition flag that is set accordingly. However, since the destination link is selected from the general roads for the reason described later, the destination recognition flag is always set to "general road".

FIGS. 8-9 are flow charts showing the control procedure in the case of calculating the route from the present location to the destination in the navigation system of this embodiment. When the current position data of the vehicle is input from the vehicle position detection unit 14 during traveling (step S1), the memory control unit 11 determines whether or not it is necessary to update the link shape data of the middle mesh including the current position. (Step S2). The link shape data of this middle mesh is used in step S3 when the vehicle moves.
Since the departure point link in the route calculation performed in 5 changes, it is updated to obtain a new departure point link. The method of obtaining the departure point link will be described later. The processes of steps S1 and S2 are repeated at regular intervals (for example, 1.2 seconds) when the current position data of the vehicle is updated.

If it is necessary to update, read new link shape data (4 medium meshes around the vehicle) DR
It is stored in a predetermined area of the AM 163 (step S3). Next, it is determined whether to update the second layer link compressed data (step S4). The judgment criteria are as follows. FIG. 11 is a second layer map around the current position of the vehicle, and each square represents a medium mesh. Current position of the vehicle is represented by P _n, 1 cycle position in front of the vehicle is represented by P _n-1. When the vehicle position is P _n-1 , the thick frame W
The link compression 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, when the position of the vehicle is within the adjacent middle mesh P _n , the nine meshes surrounded by the thick frame W _n become the area around the current location, and the second layer data in this area is updated. Need to do. Therefore, it is necessary to newly acquire the data related to the middle mesh B ₁ -B ₅ and release the data related to the middle mesh C ₁ -C ₅ . In this way, when it is necessary to acquire and release compressed data, it is determined that the entire second layer link compressed data needs to be updated.

When it is determined that the update is necessary, the upper mesh pointer file is read (step S
5). The reason why the upper mesh pointer is read 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 acquired is estimated by the upper mesh pointer, and this is calculated as B
(Step S7). Also, the second trying to release
The size of the layer is estimated by the upper mesh pointer and is set as C (step S8). Then, it is determined that A + CB-> 0 (1) (step S9), and if the expression (1) is not satisfied, the link compression data having a lower priority is dropped (step S10). This work refers to giving up on the acquisition of all or part of the mesh data on the side opposite to the destination direction with reference to the vehicle position, for example.

If the expression (1) is satisfied, the second layer link compressed data of the middle mesh of 9 sheets (a smaller number if step S10 is applied) near the current position is acquired, and the predetermined data of the DRAM 163 is acquired. Store in area (step S
11). Next, the process proceeds to step S21 in FIG. 9 and it is confirmed whether or not the destination has been set by the driver (step S21). This setting is performed using the joystick set key on the "destination setting" menu screen.
If the destination is set, the second layer link shape data (for four medium meshes around the destination) is read (step S2).
2) Read the upper mesh pointer file (step S23), confirm the free size of a predetermined area of the DRAM 163, set this size as 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 or not AB> 0 (2) (step S26). The size of the second layer to be released is not estimated because the destination setting is not repeated every fixed period like the current position input, but once set, it is held as it is until the route calculation is completed, This is because everything is erased when finished.

If the equation (2) is not satisfied, the link compression data having a lower priority is dropped (step S27). This work means giving up on the acquisition of all or a part of the mesh data on the side opposite to the current position based on the position of the vehicle, for example. If the equation (2) is satisfied, the second layer link compressed data of the middle mesh of 9 sheets (a smaller number of sheets if step S27 is applied) near the destination is read out, and is also stored in a predetermined area of the DRAM 163. It is stored (step S28).

While acquiring the second layer link compressed data and the like, the driver performs the above-mentioned "route setting".
The calculation condition for making a route calculation request can be set on the menu screen of (step S29).
As described above, the calculation conditions are whether to give priority to a toll road, whether to use a ferry, whether to set a waypoint, and whether the departure point is an expressway or an ordinary road.

Next, it is confirmed whether or not there is a route calculation request from the driver (step S30). This route calculation request can be made by calling the menu screen, but can also be made by one-touch using the root key as the feature of the present invention. If there is a request, proceed to FIG. First, it is confirmed whether or not there is a choice between a highway and a general road as a departure point (step S32). If there is no selection, it is considered that a general road has been selected (step S
33) Perform processing.

Then, the "route calculation" screen 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, and uses the link shape data near the current location and the destination link near the destination. The third layer link compressed data existing in the middle of the current destination is read out if necessary, and the second layer link compressed data and the third layer link compressed data are used to link the starting point link and the destination link. The optimum route for traveling between is calculated and displayed (above, step S35).

In this case, when the controller 16 recognizes the departure point link, the optimum departure point link and the optimum departure point link are selected according to whether the departure point selected in step S29 is an expressway or a general road. Search for destination links. Hereinafter, the content of step S35 will be described in more detail. 1 and 2 are flowcharts detailing the contents of step S35.

First, the method of the route calculation command is determined (step S41). If the route calculation command is issued using the menu screen, it is determined whether the departure point selected in step S29 is on an expressway or a general road (step S4).
2) If it is on an expressway, the present location recognition flag is set to "high speed" (step S44), and if it is on an ordinary road, the present location recognition flag is set to "general" (step S4).
5). If a route calculation command is issued using the route key, it is determined whether or not 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 process ends. If the destination has already been set, the present location recognition flag is set to "general" (step S45). The reason for setting it to "general" is that it is usually not possible to depart from a highway except when traveling on a highway, and for the average driver, drive on a highway during the time on the highway. It's much less than you're doing.

After the present location recognition flag is set, the optimum nearest link, that is, the departure location link is determined by using the link shape data near the present 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 period, it is checked whether or not the root key has been pressed (step S4).
8). The reason for checking is to confirm the driver's request that the calculation is interrupted and the return calculation is performed using the current vehicle position as the starting point. Such a request occurs, for example, when it is found that the vehicle is traveling off the calculated route before traveling and it is desired to calculate the route again. At this time, it is a feature that the return calculation can be performed with one touch without displaying the menu screen on the display 3 of the navigation device.

When the root key is pressed, step S is executed again.
Enter 43. At this time, the calculation conditions set in step S29 remain unchanged. That is, after determining that the destination has been set (step S43), the current location recognition flag is set to "general".
Is set (step S45), and the nearest link, that is, the departure point link is recognized again using the link shape data near the current location (step S47). The reason for re-recognizing the departure point link is that the previously recognized departure point link may not be suitable because the vehicle is traveling.

If the route key is not 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 setting a point on a highway as a destination is unthinkable unless it is a highway patrol or highway maintenance.

Then, as in step S48, it is checked whether or not the root key has been pressed (step S5).
1) If the root key is pressed, the process goes to step S43 again. If the root key is not pressed, step S in FIG.
Proceeding to 61, the third layer link compressed data in the intermediate area is read. When the third layer link compressed data is required, for example, when the present location and the destination are distant from each other and a highway or the like is used, the third layer link compressed data is read. However, if the present location and the destination are close to each other and there is no need to use a highway or the like, it is not necessary to read the third layer link compressed data in the intermediate area.

Then, between the departure point link and the destination link, the route is calculated according to the calculation conditions set in step S29 (step S62), and the optimum route display data as the calculation result is created (step S64). ), And display it on the road map (step S65). During the route calculation, as in step S48, it is checked whether or not the root key is pressed (step S63). The reason for this is
This is to confirm the driver's request that the calculation is interrupted and the return calculation is performed with the current vehicle position as the starting point, 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 is processed and modified. Therefore, the road map data is not reused, these road map data are once deleted, the map data (link shape data and link compressed data) near the current location and the destination is read out again (step S66), and returns to step S46.

Next, the nearest link recognition process (step S
47, 50) will be described in detail. 12 and 13 are flowcharts for explaining the nearest neighbor link recognition processing. To explain along the flow of the figure, a variable called "link distance" for finding the nearest link is introduced for expressways and for general roads, respectively. The link distance for the expressway is L ₁ , and the link distance for the general road 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 is, 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 which is not necessary for the recognition of the nearest link. Therefore, one medium mesh is divided into 16 sections, and 4 sections (referred to as 1 block) including the current position are set as the search range. FIG. 14 shows one block in which one medium mesh is divided into 16 sections and the current position is included. If the current position is within the threshold line indicated by the dotted line, the one surrounding the threshold line is surrounded. The block becomes the search range. Therefore, if the current position is near the end of the middle mesh, one block will be taken including other middle meshes.

An example of the method of calculating the distance d in step S74 will be described. An arbitrary pair (2 points) is taken from the start point, the end point, and the interpolation point of the shape link, and the distance between the current position and 2 points is d ₁ respectively. , D ₂ . FIG. 16 shows an example in which the distances d ₁ and d ₂ are set between the interpolation points a and b. If either 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, regarding the same shape link, two arbitrary points are taken from the remaining pairs of the start point, the end point, and the interpolation point, and compared with the upper limit value. If smaller than the upper limit value, the same process as above is performed to calculate the vertical distance. . If vertical distances can be calculated for all pairs of one shape link, they are compared with each other, and the shortest vertical distance is used as the distance d between the current position and the shape link.

Next, in step S75, it is determined whether the shape link is a highway link or a general road link.
If it is an expressway 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 decision is made to find only the links near the current location. If it is smaller than the threshold value, the distance d is the highway link distance L ₁
It is determined whether or not it is smaller (step S78). Since the highway link distance L ₁ is initially set to a sufficiently large value, “YES” is determined and the process proceeds to step S80. In step S80, the value of the distance d is substituted for the highway 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 road link is a general road, it is determined whether the distance d is smaller than the threshold value (step S77). If it is smaller than the threshold value, it is determined whether the distance d is smaller than the general road link distance L ₂ (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. In step S81, the value of the distance d is substituted for 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, and if all have not 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, at the end, the nearest links corresponding to the highway and the general road can be found, if any. It will be.

In step S81, the link distance L ₁ for the expressway and the link distance L ₂ for the general road are checked to determine whether the nearest links corresponding to the expressway and the general road have been found. If not found, the link search range is changed to, for example, 800 m in step S82 (step S83),
Search again for the nearest link. If it is not found even after searching at 800 m, error processing is performed.

If the nearest link is found, the process proceeds to step S91 in FIG. In step S91, the link recognition flag is checked to determine whether the highway or the general road is selected as the departure link. If the expressway is selected, it is checked in step S92 whether the nearest link corresponding to the expressway is registered,
If "YES", the link number and mesh code of this 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 mesh code of this nearest link are output (step S).
97). The same process is performed when the general road is selected (steps S93, 95). Thus, high speed (general)
If the nearest link corresponding to the road is not registered,
The two-stage approach of outputting the nearest link corresponding to a general (highway) road is the second best measure even if the route cannot be calculated from the type of road requested by the driver. This is because the route can be calculated from the road.

The processing for recognizing the nearest link in FIGS. 12 and 13 described above is similarly applied not only when searching for a departure point link on the current side, but also when searching for a destination link on the destination side. It is something. However, in this case, since the highway is not designated, the destination link is searched from the general road links. As described above, the route can be calculated using the nearest link corresponding to the type of road requested by the driver as the departure link and the nearest link corresponding to the general road as the destination link. Further, if there is a request to interrupt the calculation and perform the return calculation during the optimum route calculation by the route calculation means, the return calculation can be performed by manually inputting the return calculation request signal with one touch using the root key ( Steps S48, 51,
63), the driver can calculate the return route safely and promptly without calling the menu screen or the road map while driving.

[0059]

As described above, according to the present invention as set forth in claim 1, when one-touch operation is performed during or after the calculation of the optimum route, the work is performed on the condition that the destination is input at least. Using the road map data near the vehicle's current location stored in the area, a link near the current location is newly recognized, and a route is calculated between the link near the current location and the link near the already specified destination. Therefore, the optimum route can be easily obtained when the calculation conditions cannot be set practically, such as when the vehicle is traveling, or when the vehicle deviates from the route calculated before traveling.

Further, as described in claim 2, the road map data around the current location is acquired, stored in the work area, and updated if necessary so that the road map data around the current location can be used at all times. If a driver who wants to calculate a route makes a one-touch operation at any time, the road map data etc. stored in the work area can be immediately called to perform the route calculation. Compared with the case of acquiring map data,
The effect that the route calculation time is shortened by the acquisition time of the road map data is obtained. This is particularly advantageous when the optimum route is suddenly required while the vehicle is traveling.

[Brief description of drawings]

FIG. 1 is a flowchart detailing the contents of a link recognition process.

FIG. 2 is a flowchart (details of FIG. 1) detailing the contents of link recognition processing.

FIG. 3 is a block diagram showing a configuration of a navigation device according to an embodiment of the present invention.

FIG. 4 is a front view of a remote control key.

FIG. 5 (a) is an illustration showing a shape link that is a polygonal line with directions along the shape of a road, and (b) is an illustration showing a compression link used only for route calculation ignoring the shape of the polygonal line. It is a figure.

FIG. 6 is a diagram showing a storage structure of road map data for route calculation.

FIG. 7 is a diagram showing a route setting screen which is one of menu screens.

FIG. 8 is a flowchart 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 the route calculation processing procedure according to the embodiment of the present invention.

FIG. 10 is a flowchart (continuation of FIG. 9) for explaining the route calculation processing procedure according to the embodiment of the present invention.

FIG. 11 is a second layer map around the current position of the vehicle.

FIG. 12 is a flowchart detailing the content of the nearest link search process.

FIG. 13 is a flowchart (continuation of FIG. 12) detailing the content of the nearest neighbor link search process.

FIG. 14 is a diagram showing a state in which one medium mesh is divided into 16 sections and 4 blocks.

FIG. 15 is a diagram exemplifying a positional relationship between a current position and interpolation points a and b of a shape link.

FIG. 16 is a diagram showing a vertical distance between a straight line connecting interpolation points a and b and the current position.

[Explanation of symbols]

 1 navigation device main body 2 CD drive 3 display 4 remote control key 5 GPS receiver 6 ECU 11 memory control unit 12 display control unit 14 vehicle position detection unit 16 controller 161 CPU 163 DRAM D map dedicated disc

Claims (5)

[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 various calculation conditions such as a destination. Calculation condition input means, and first loading means for reading the road map data near the current position stored in the road map storage means based on the current position data of the vehicle output from the position detection means and storing the read road map data in the work area.
Second load means, first load means, and first load means for reading the road map data near the destination stored in the road map storage means and storing it in the work area when the destination is input from the calculation condition input means. (2) The link recognizing means that reads each road map data stored in the work area by the loading means and recognizes the links near the current location and the destination, respectively, and the link recognizing means that uses the road map data to link near the current location and the destination. A route calculation device comprising route calculation means for calculating an optimum route according to a specified calculation condition when traveling between, further comprising key input means capable of inputting a calculation request signal with one touch, and the link recognition means. Is a calculation condition input when the calculation request signal is inputted by the key input means during the calculation of the optimum route or after the calculation. On the condition that the destination has already been input by the step, the first load means newly recognizes a link close to the current location using the road map data near the current location of the vehicle stored in the work area, and calculates the route. A route calculation device characterized by causing a means to perform calculation. 2. The position detecting means repeatedly obtains the current position of the vehicle based on signals from various sensors while the vehicle is traveling, and the first load means is a vehicle from the position detecting means associated with traveling of the vehicle. 2. The route calculation device according to claim 1, wherein the road map data in the vicinity of the current position to be stored in the work area is updated based on the current position information. 3. The various calculation conditions input by the calculation condition input means include where the destination is, whether to give priority to a toll road, whether to use a ferry, whether to set a waypoint, and departure. Each calculation condition such as whether the point is a highway or a general road is included, and when the calculation request signal is input by the key input means, the route calculation means The route calculation device according to claim 1, wherein the route calculation is performed according to the calculation condition set in (1). 4. The various calculation conditions input by the calculation condition input means include where the destination is, whether to give priority to a toll road, whether to use a ferry, whether to set a waypoint, and departure. Each calculation condition such as whether the point is an expressway or an ordinary road is included, and when the calculation request signal is input by the key input unit, the route calculation unit sets each calculation condition to the purpose. The route calculation device according to claim 1, wherein the route calculation is limited to one of the predetermined options except the ground. 5. The route calculation device according to claim 1, wherein the calculation condition input means inputs various calculation conditions on a display screen attached to the route calculation device.