JPH02277200A - On-vehicle navigator - Google Patents

Abstract

PURPOSE:To acquire a desired route for a driver and to reduce the traffic snarl degree by securing a constitution where the driver sets a destination and the desired route calculation conditions and calculate a recommended route via a route calculation means based on the route calculation conditions set by an initialization means. CONSTITUTION:A 1st CPU included in a route calculation part 7 sets the evaluation function Fi of an equation I in accordance with a route mode selected via an initialization part 6. At the same time, the road network data is read out of a map memory 3 in accordance with a set destination. Then a recommended route reaching an end point node from a start point is calculated based on the function Fi. In addition, a new recommended route is calculated based on the traffic snarl information received from a communication equipment 14 and stored in a main memory 8. The CPU reads the road map data out of the memory 3 as a vehicle get closer to the start/end point nodes and a junction point. Then the road map data is rotated around the center position of the vehicle to secure a format of an easy-to-see display form. This format is transferred to an output controller 12 and at the same time a warning is given to a voice output device 15 to show that the vehicle reaches the junction point.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a self-contained in-vehicle navigator, and more specifically, to a road map stored in a map memory according to a destination setting by a driver. A new in-vehicle device that reads road map data for a range that includes the current location and destination from the data, calculates a recommended route from the current location to the destination based on this road map data, and guides the vehicle along this recommended route. Regarding navigators.

<Prior Art> In-vehicle navigators are known that have been developed to display routes and the like on a screen to facilitate driving in unfamiliar areas or at night.

Conventional in-vehicle navigators are equipped with a display, direction sensor, distance sensor, map memory, computer, etc. in the vehicle, and are based on direction change data input from the direction sensor and mileage data input from the distance sensor. This is based on so-called dead reckoning, which calculates the coordinate position based on the coordinate position and displays the coordinate position redundantly on the road map displayed on the screen. ■ A further development of the navigator using dead reckoning described above, which calculates the coordinate position and displays the coordinate position redundantly on the road map displayed on the screen. There is a so-called map matching navigation method in which the vehicle position on the road is detected based on the coincidence with the road, and this vehicle position is displayed on the road displayed on the screen.

In both of the above navigators, in order to guide the vehicle to the destination, the location of the destination is displayed on the road map displayed on the screen, and the route from the current location to the destination is determined by the driver. was.

Very recently, before starting the journey, the driver is required to input the destination and desired route mode (specifically, the shortest distance route, the shortest time route, etc.), and the travel time or travel distance is set as a parameter. A navigator has been proposed that guides a vehicle by calculating the shortest route from a current location to a destination, and superimposing and displaying the calculated route on a road map.

The method for calculating the route from the current location to the destination is as follows:
The so-called Dijkstra method is adopted. This method assumes a network from a starting point node to an end point node, and calculates a route to a destination by sequentially adding all segments branching from each node. If you calculate a route using this method, you will definitely reach your destination as long as there is a route from your current location to your destination.

Further, as vehicle guidance methods, there are methods in which the recommended route is superimposed on a road map of a predetermined scale and displayed on the screen, and methods in which only the direction of travel of the vehicle is displayed using arrows in 8 to 16 directions.

<Problem to be solved by the invention> However, if time and distance are used as the elements for route selection, the following problem arises because the route is calculated based on one type of parameter selected by the driver. be.

■If routes are calculated using the same parameters, a large number of vehicles will be traveling on the same route, which will instead lead to traffic congestion (so-called hunting phenomenon).

■Traffic volume varies depending on the time of day, social circumstances such as traffic accidents, road construction, festivals, etc., and the shortest route is not necessarily the shortest route. Even the shortest route is forced to change its route due to unpredictable variable factors as described above. Therefore, there is little significance in setting parameters uniquely.

■The route mode may need to be changed depending on the driver's personality, age, and mood at the time. If the parameters are set uniquely, there is a problem in that it is not possible to deal with changes in the route mode.

Further, when a route is calculated using the Dijkstra method, the number of road segments increases by the square of the number of road segments, assuming that a node has two branch roads in the direction of travel.

Therefore, when the number of nodes is large, there is a problem in that it takes time to complete route calculation.

Furthermore, the recommended route is superimposed on a road map of a predetermined scale and displayed on the screen, so the recommended route is displayed on a road map of about 1/10,000, so it can be easily viewed from the road map.

Although it is possible to roughly grasp one's own position, there is a problem in that when approaching a fork in the road, it is difficult to instantly judge in which direction to proceed.

On the other hand, arrows in 8 to 16 directions that display only the direction of travel of the vehicle are displayed in a simple pattern, so
It has excellent visibility, allowing you to know the route to take in an instant, and because the display format is simple, it has the advantage of requiring less map data to be stored in the map memory. . However, it is not possible to display branch points where elevated roads and the like are complicated. Furthermore, since the road map is not displayed, it is not possible to determine one's own position on the map. Furthermore, when searching for a destination in unfamiliar territory, there is a problem in that it is not possible to search by displaying the shape of a branch point.

As mentioned above, in both cases where the recommended route is superimposed on a road map of a predetermined scale and displayed on the screen, and where only the direction of travel of the vehicle is displayed using arrows in 8 to 16 directions,
There are pros and cons. Additionally, there is the problem that the required display format differs depending on the attributes of each road (whether it is a main road or not), the attributes of each junction (whether the shape is complex or not), the driver's unfamiliarity with the terrain, etc. be.

This invention has been made in view of the above-mentioned problems, and aims to make it possible to change the parameters required for route calculation according to the driver's preference, and to alleviate the traffic hunting phenomenon. In addition, with the aim of reducing the time required for route calculation, the display format is changed depending on the attributes of the road, the attributes of each junction, and the degree of unfamiliarity of the driver. The purpose is to make it possible to

Means for Solving the Problems and Effects> As shown in FIG. map storage means (A) storing road map data consisting of background data such as; position detection means (B) for detecting the vehicle position; The initial setting means (C) reads road map data in a range including the current location and destination from the map storage means (A), and uses this road map data and the route calculation conditions set by the initial setting means (C). a route calculation means (D) for calculating a recommended route based on the vehicle position data; a storage means (E) for storing the recommended route; and a branch point on the recommended route based on the vehicle position data detected by the position detection means (B). vehicle guidance means (F) for detecting the approach of the vehicle, reading road map data including the approached branch point from the map storage means (A), and enlarging and displaying the road map data along with the vehicle position and the recommended route; It is.

If the invention has the above configuration, the driver can use the initial setting means (C).
Operate to set the destination and desired route calculation conditions,
By calculating the recommended route by the route calculation means (D) based on the route calculation conditions set by the initial setting means (C), it is possible to provide a route desired by the driver.

Then, the vehicle guiding means (F) reads road map data including the branch point from the map storage means (A) each time the vehicle approaches a branch point of the recommended route stored in the storage means (phantom); Road map including the branch point, current location,
By enlarging and displaying the recommended route, it becomes easier to visually confirm the direction of travel, and the driver can drive safely.

Further, the initial setting means <C> allows the driver to select any one route calculation condition from a plurality of route calculation conditions set based on the following evaluation function F1, and also allows the driver to select one route calculation condition from among the plurality of route calculation conditions set based on the following evaluation function F1, and also to An in-vehicle navigator characterized in that α can be changed to a value desired by a driver.

F! =Σ(α11xAm) ...(I)(
However, i is the number of path modes, Σ(αcm)−1, and a
m (m=1.2.-n) is the weighting index of Al11, and A is the attribute of the link) In the above initial setting means (C), the value of the weighting index of the evaluation function F1 is set to By changing the route calculation conditions to the driver's preference, the route can be set according to the driver's mood at the time. Then, the route calculation means (D) calculates a recommended route from the current location to the destination based on the above settings or the changed evaluation function, thereby providing a recommended route desired by the driver. . Moreover, since this evaluation function takes into account the human factors unique to the driver, the recommended route calculated based on this evaluation function is different from conventional standardized routes, and has a random nature. There is,
It is possible to prevent a large number of vehicles from concentrating on the same road.

Furthermore, the map memory (A) of claim 1 stores the road network data classified according to the road type from the highest layer map with the widest node interval to the lowest layer map with the narrowest node interval. , the route calculation means (D) sets a route search area based on the straight-line distance from the current location to the destination, and when the route search area is on the same layer, the route calculation means (D) sets a route search area based on the straight-line distance from the current location to the destination, and when the route search area is on the same layer, from a node near the current location on the same layer. A route is calculated by adding the links leading to nodes near the destination, and if the route search area is not on the same layer, search for interlayer connection nodes that connect lower and upper layers from the road network data. , a route from a node near the current location to an interlayer connection node on the current location side, a route from a node near the destination to an interlayer connection node on the destination side, and a route from an interlayer connection node on the current location side to an interlayer connection node on the destination side. The method is characterized in that it calculates a route from a node near the current location to a node near the destination by summing the routes.

If the above map memory (A) and route calculation means (D) are combined, if multiple layers are set as the route search area, the interlayer connection node connecting the lower layer and the higher layer will be connected to the road. Since the search is based on network data, the route calculation in the lower hierarchy calculates the route from the node near the current location to the interlayer connection node on the starting point side of the recommended route, and from the interlayer connection node on the end point side to the node near the destination in the same hierarchy. Since routes between interlayer connection nodes are calculated within a widely set upper hierarchy, the time required for route calculation can be reduced even if the route is long or short.

Furthermore, the route guiding means (F) displays the starting point and the vehicle position superimposed on the road map from the current location to the starting point of the recommended route calculated by the route calculating means (D>) according to claim 3, While driving on the recommended route, the recommended route, vehicle position, and shape of the branch point are displayed on the entire screen or in the window of the screen, and from the end of the recommended route to the destination, the destination and The vehicle position is displayed on a road map.

With the above route guidance means (P), by displaying the vehicle position, the starting point or destination of the recommended route together with the road map, it is possible to grasp one's own position within a wide area, so the vehicle travels relatively easily. It can be used when driving on narrow streets with slow speeds or when driving on geographically unfamiliar streets.

In addition, by displaying the recommended route, vehicle position, and shape of the junction on the entire screen or in the window of the screen, the vehicle can instantly judge the shape of the junction, just like on a main road. Can be used on certain roads.

In addition, the route guidance means (P) displays a road map and vehicle position, or displays a recommended route, vehicle position, and Display of the shape of junctions, road maps, recommended routes,
It is characterized by being able to switch to a display that combines the vehicle position and the shape of the branch point.

If the above route guidance method (F) is used, on highways running at high speed, at junctions, and in relatively well-known areas,
By displaying only the recommended route, the vehicle position, and the shape of the branch point, it is possible to instantly know which route to take, so the vehicle can travel safely. In addition, since the road map is displayed on narrow streets where high speed travel is not possible or in areas where the terrain is unfamiliar, the vehicle can drive while knowing its own location on the map.

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

FIG. 2 is a block diagram showing the in-vehicle navigator.

The in-vehicle navigator has a display (1), a console (
2), map memory (3), memory drive (4), touch panel (5), initial setting section (6), route calculation section (7)
, main memory (8), distance sensor (9), direction, position sensor 0
0), locator (11), output controller (12),
and an input/output interface (13). still,(
14) is a communication device for receiving road information transmitted from the control station, and (15) is an audio output device for notifying that the vehicle is approaching an intersection.

Display (1) displays the initial settings menu, road map,
The vehicle position, recommended route, etc. are displayed at predetermined dot positions. This display (1) includes CRT,
Liquid crystal panels etc. can be used.

The console (2) has a key board (not shown) for starting and stopping the device, moving the cursor on the screen, manually scrolling the road map displayed on the screen, etc.

The map memory (3) divides the Japanese road map into meshes, and stores road data consisting of combinations of nodes and links in each mesh, and road map data consisting of background data such as buildings.

This road map data is used for graphic display and route calculation. This map memory (3) is a CD-
Mass storage media memory such as RO 14, magnetic tape, etc. can be used.

The map memory (3) will be explained in more detail.

Map memory (3) divides the Japanese road map at a scale of 1/2500 or 1/10,000 with a difference in longitude of 1 degree and a difference in latitude of 40 minutes.
A first-order mesh (see Figure 5 C) with a vertical and horizontal distance of approximately 80Km x 80Kn+, and a
A second mesh is divided into equal parts, with a vertical and horizontal distance of about 10 Km x 10 Km (see diagram 5), and this second mesh is further divided into 10 equal parts, with a vertical and horizontal distance of about I Km x 10 Km.
and a third-order mesh (see Fig. 5C). The road network data from the primary mesh to the tertiary mesh is then ranked into three layers, from the primary layer to the tertiary layer.The roads in the primary layer are composed of expressways and main arteries, The roads in the next layer are composed of the roads in the first layer plus general arterial roads, and are
The next year's roads consist of all streets, including narrow streets.

A node consists of a branch point node and an auxiliary node placed between the branch points. The node data includes the node number, the address of the upper or lower node corresponding to the node number, or the address of the adjacent mesh node, the address of the adjacent node,
There are addresses of links connected to nodes, etc.

The link data includes the link number, the addresses of the start and end nodes of the link, the distance of the link, the time required to travel through the link, the type of road (expressway, main road, city road), road width, one-way streets and tolls. Traffic regulations on roads, etc.

The background data includes railways, rivers, place names, famous facilities, points registered in advance by the driver, contour lines, etc. As a general rule, the contour lines mentioned above are not displayed, but are used as a reference when setting the route mode.

Note that the above-mentioned node intervals can be set to even narrower intervals depending on the capacity of the map memory (3) and the processing speed of the route calculation section (7).

The touch panel (5) is attached to the screen of the display (1), has transparent electrodes arranged in a matrix, and outputs touch positions by the driver to the initial setting section.

The initial setting section (6) includes a road map for setting a destination,
The display (1) displays multiple route modes based on the evaluation function Fl shown in the formula (1) below, as well as numbers for changing the value of the weighting index αm of the evaluation function Fl, and allows the driver to select the display position. Touch to set the destination and desired route mode.

Fl=Σ(αmiXAm)...
(I) (where i is the number of path modes, Σ(am)-1, am (m-1,2,-n) is the weighting index of Am, and Am is Al; the total travel of the path Time, A2, Total travel distance of the route ÷ Speed coefficient, A3, Total travel cost of the route, 1 unit Time cost coefficient, A4; Total number of left turns on the route x Left turn time coefficient, 10 Total number of right turns on the route x Right turn time coefficient, A5 , signal passing time x number of times the signal passes, etc.) To explain in more detail, the destination, the setting of the evaluation function Fl, etc. are performed according to the initial setting menu displayed on the display (1). The initial setting menu includes: (1) Point setting menu: A road map is displayed and the driver is asked to touch the destination and the point on the way on the road map.

(2) Route mode setting menu: Displays a plurality of route modes corresponding to the evaluation function Ff whose weighting index αm has been set by the driver in advance, and causes the driver to touch the desired route mode position. The route modes include a mode that prioritizes the shortest route with the largest weighting index αI of the time element Am of the evaluation function Fi, a mode that prioritizes the shortest route with the largest weighting index α2 of the distance element A2, and a mode that prioritizes the shortest route with the largest weighting index α2 of the distance element A2. There is a mode in which the least expensive route with the largest weighting index α3 of element A3 is given priority, and a mode in which priority is given to the route with the least number of left and right turns in which the weighting index α4 of the number of left and right turns is made the largest. In addition to the above route modes, there is also a route mode that prioritizes tourist spots, a route mode that prioritizes familiar roads, a route mode that prioritizes mountain roads, a route mode that prioritizes roads along the coastline,
There are route modes that give priority to wide roads. The above route modes can be set in accordance with the link data (type, distance, travel time, etc.) stored in the map memory (3) and background data (place name field, famous facilities, contour lines, etc.) .

(2) Index setting menu: Displays the value of the weighting index for changing the contents of the evaluation function Fl, and allows the driver to touch the desired weighting index value. For example, when the weighting index αl is set to 1, the evaluation function Fj becomes Fl-Am, and the calculated route becomes the shortest time route.

■Other setting menus: Displays display types such as rotation mode, which fixes the direction of travel of the vehicle and rotates the surrounding map, and fixed mode, which fixes the map in the north direction.
There are menus and the like that allow the driver to touch a desired display mode position. Please note that the above destination input can be done using the console (
You may input by operating the keys in 2). In this case,
Point data such as a place name field on a road map, a famous facility field, or a point registered in advance by the driver may be selected and input.

Further, it is possible for the driver himself/herself to designate intermediate points.

The route calculation unit (7) calculates the current location (vehicle position detected by the locator (11)), recent nodes on the main road, and the destination from the map memory (3) according to the destination setting by the driver. Read the road map data of a predetermined range including the node on the main road in the recent example.Hereafter, the node on the main road near the current location is the start node, and the node on the main road in the recent example as the destination is the end point. (abbreviated as node)
Furthermore, a recommended route from the starting point node to the ending point node is calculated based on Dijkstra's method under the condition of the evaluation function Fi corresponding to the route mode set by the driver.

Further, the contents of the evaluation function Fl are changed by the driver according to the value of the set weighting index αm, and a recommended route from the start point node to the end point node is calculated based on the changed evaluation function. This calculation of the recommended route is performed by searching for a node in the upper mesh based on the node address of the upper mesh connected to the start point node and the end point node, and using the road map data of the upper mesh.

The main memory (8) temporarily stores the recommended route calculated by the route calculation unit (7). Specifically, branch point nodes are stored.

Locator (11) is map memory (lla) for position detection
and a microcomputer (LLB). The position detection map memory (lla) is within a predetermined range (for example,
All the roads in the 11,500-scale road map are divided into predetermined distances, dividing nodes, branching point nodes, and addresses of adjacent nodes are stored in association with each node. The node positions are set to approximate the roads on which the vehicle actually travels. The above microcomputer (ll
b) calculates travel trajectory data by integrating the distance data detected by the distance sensor (9) and the direction change data detected by the orientation sensor 00), and stores the travel trajectory data and the map memory for position detection ( The vehicle position is detected based on the similarity with the road pattern stored in lla). The orientation sensor (10) detects changes in orientation as the vehicle travels, and includes a geomagnetic sensor, a gyro, and a wheel speed sensor that detects the turning angle based on the difference in rotational speed between the left and right wheels. It is possible to use. Further, the distance sensor (9) detects the traveling distance based on the speed of the vehicle, the number of rotations of the wheels, etc.
Wheel speed sensors, vehicle speed sensors, etc. can be used. Note that it is also possible to share the map memory (lla) for position detection and the map memory (3).

FIG. 3 is a diagram showing the hardware configuration of the path calculation unit (main memory (8), and output controller (12)), in which the path line (16) includes the main memory (8), 1st ROM (17) storing the program;
2nd ROM (18
), a route calculation program and a first route calculation program that calculates a recommended route and provides route guidance based on the route calculation program.
CPU (+9), input/output interface (13)
, and a second CPU (20) for display are connected. A frame memory (21) is connected to the second CPU (20) for display. Further, a communication device (14) and an audio output device (15) are connected to the input/output interface (13). That is, the lth ROM'(1
7), second ROM (18), first CPU (1
9) performs route calculation and route guidance. 2nd CP
An output controller (12) consisting of a U (20) and a frame memory (21) displays a road map etc. in a predetermined format.

The first CPU (19) sets the evaluation function Fi according to the selected or changed route mode from the initial setting section (6). Also, depending on the set destination, road network data including starting point nodes and ending point nodes can be stored in the map memory (
3) Read from (second layer or using second layer). Next, a recommended route from the starting point node to the ending point node is calculated based on the evaluation function Fl set above. It also calculates a new recommended route based on information such as traffic jams input from the communication device (14). Then, the calculated recommended route is temporarily stored in the main memory (8), and each time the vehicle approaches the start node, end node, or branch point stored in the main memory (8), the map memory Read road map data including branch points from (3), convert the read road map data into rotation display data for display by rotating it around the vehicle position, and format it into a display format with good visibility. It is converted and transferred to the output controller (12).

Additionally, a warning sound indicating that the vehicle is approaching a fork is output to the audio output device (5).

The second CPU (20) is the first CPU (
19) is written into the frame memory (21) and displayed on the display (
1) is displayed.

FIG. 4 is a diagram for explaining the above display format, FIG. 4A shows the display format before the vehicle approaches the starting point node (a) of the recommended route, and FIG. 4B shows the display format before the vehicle approaches the starting point node (a). (
It is a figure which shows the display form when approaching a). That is, when the vehicle is a predetermined distance away from the starting point node (a), a road map of a wide range is displayed, and the vehicle is away from the starting point node (a).
), the display switches to an enlarged display of the road map including the starting point node (a), the vehicle position (C), and the recommended route m.

Note that by setting a window on the screen, it is possible to display a highly visible display form within the window, and to display a wide range of road maps outside the window.

The operation of the in-vehicle navigator having the above configuration will be explained based on the initial setting menu display diagram in FIG. 5, the recommended route calculation flowchart in FIG. 6, the mesh layout diagram in FIG. 7, and the route guidance flowchart in FIG.

The initial setting operation is as follows.

That is, (1), a mode that gives priority to a route with a short travel time, a mode that gives priority to a route with a short travel distance, a mode that gives priority to a route with a low travel cost, etc. are displayed on the display (1). The driver touches the desired mode position to designate the mode for route calculation (see Figure 5C).

°■1 Next, the driver is asked whether or not to change the weighting index through the screen. If the answer is No, a recommended route is selected in the previous mode. If the answer is YES, the weighting index αm and numerical values for setting the index αm are displayed. The driver touches the numerical position (see Figure 5C).

(2) Change the weighting index α field of the evaluation function F1.

■Display the road map of the 1st layer on the 0th screen (5th
(See Figure C). In addition, if you omit the input processing of ■, ■, and ■ above and input this ■, a predetermined route mode (selected by the driver from the route modes of ■ above) is selected. be done.

0. Touch the mesh position (Taito Ward in the drawing) that includes the destination of the first layer. Next, a road map of the entire specified Metsu (Taito Ward) is displayed (see the fifth diagram).

■Touch the mesh position that includes the secondary level layer target area (in the drawing, the block that includes Ueno Park). This designated tertiary mesh position may be used as the destination. Next, a road map of the central portion of the specified third mesh is displayed.

Search for the destination by scrolling the 0.3-dimensional mesh road map and touch the destination position (see Figure 5C).

01 After the initial settings are input as described above, the current location is returned to the display (see FIG. 5C), and a recommended route is calculated.

Figure 6 is a recommended route calculation flowchart, and Figure 7A
indicates the case where the straight line distance between the current location and the destination is short;
Figure B is a diagram showing a case where the distance is long.

In step (2), the vehicle position from the locator (11) and the aforementioned destination are input. In Ste, Tsubu■, if the current location or destination is on a narrow street, it is not subject to automatic search, and the node on the main road closest to the current location is set as the starting point node (a), and the node closest to the destination is set as the starting point node (a). A node on a certain trunk road is assumed to be an end point node (b). In step ■, it is determined whether the straight line distance J from the current location to the destination is longer than a predetermined distance X (this distance If it is determined that J is shorter than the predetermined distance X, a rectangular area including the current location and destination of the secondary layer is set in step
reference). In step (2), a recommended route is calculated based on the evaluation function Fmi corresponding to the previously set route mode. In step ■, it is determined whether the recommended route to the end point node (b) has been calculated, and if it is determined that the recommended route has not been calculated, in step ■,
Enlarge the rectangular area and perform steps ① to ②.

In this case, the number of times the area is expanded is set in advance to prevent an endless loop.

If it is determined in step (2) that the recommended route has been calculated, the process flow is terminated in step (2).

If it is determined in step (2) that the straight line distance is longer than the predetermined distance, then in step (2) a square area including the current location is set in the secondary layer (see FIG. 7B). In step [phase], the secondary layer is searched to find the secondary mesh node connected to the starting point node, and the primary mesh node (hereinafter, this node will be abbreviated as the starting point side interlayer connection node (C)). ) and calculates a recommended route from the starting point node (a) to the starting point side interlayer connection node (C) based on the evaluation function Fi. In step ■, it is determined whether the recommended route to the starting point side interlayer connection node (C) has been calculated, and if it is determined that the starting point side interlayer connection node (C) has not been calculated, in step @, Expand the square area and step [shares]
, (2) is performed. Even in this case, the number of times the area can be expanded is limited to avoid an endless loop. If it is determined in the above step (2) that the recommended route to the starting point side interlayer connection node (C) has been calculated, in step 0, the process goes to the first layer and sets a rectangular area. In step (2), a recommended route from the starting point side interlayer connection node (c) to the square area including the destination point side is calculated based on the set evaluation function Fmi. In step ■, it is determined whether the square area on the end point side has been reached (that is, whether the recommended route has been calculated or not), and if it is determined that the recommended route has not been calculated, step ] Repeat the process.

If the recommended route has been calculated in step (2) above, in step (2), a node connected to the end node (b) within the square area (hereinafter, this node will be abbreviated as the end point side interlayer connection node (d)) ) In step (2), the recommended route from the end point side interlayer connection node (d) to the end point (b) is determined using the set evaluation function F.
Calculate based on j. In step [Yes], it is determined whether a recommended route from the end-point side interlayer connection node (d) to the secondary layer has been calculated, and if it is determined that a recommended route has not been calculated, in step Expand the square area and perform steps ■ and @. If it is determined in step [Yes] that the recommended route has been calculated, the process flow is ended in step (2).

According to the above recommended route calculation flowchart, the area of the secondary mesh is limited to a rectangular area for short-distance route calculations or a square area for long-distance route calculations based on the straight-line distance from the current location to the destination. However, in the case of short-distance route calculation, only the road network data within the rectangular area is read out, which reduces the time it takes to read out the road network data. Since the route is calculated by adding the road segments in , the route calculation time from the starting point node (a) to the ending point node (b) can be greatly shortened.

In addition, in the case of short-distance route calculation, the route between the starting point node (a) and the starting point-side interlayer node (C) in the second mesh, in the same manner as in the case of short-distance path calculation described above, within the square area, and end point node (b) and end point side interlayer node (d)
The route between the starting point side interlayer connection node (C) and the end point side interlayer connection node (d) is calculated within the upper layer, which is roughly set, so even if the route is long, Even for distance routes, the time required for route calculation can be reduced.

Note that the route calculation device described above can perform the following processes in addition to the above. That is, on any road segment of the narrow street, there is a starting point node (a) and an ending point node (b).
Both settings are possible. However, if city roads are also targeted, vehicles may detour onto city roads, resulting in congestion, so as a general rule, arterial roads are targeted.

■Also, if your current location or destination is on a main road,
The current location is the starting point node (a), and the destination is the ending point node (a).
b).

■, In advance, the starting point node (a) and the starting point side interlayer connection node (C
) and the recommended route connecting between the end point node (b) and the end point side interlayer connection node (d), and then calculate the recommended route connecting the end point side interlayer connection node (c).
A recommended route connecting between the terminal and the end-point side interlayer connection node (d) is calculated.

■Recalculate while driving at constant speed.

(2) The driver specifies a branch point on the city road based on the map, and sets a route from the current location to the starting point node (a) and a route from the destination to the ending point node (b).

(2) When traffic information such as congestion, accidents, and road construction is obtained from the control station, a recommended route is calculated that takes into account detours, etc.

FIG. 8 is a diagram showing a route guidance flowchart.

In step (2), until the vehicle approaches the starting point node (a), a road map on which the vehicle position (e) and starting point note (a) are superimposed is displayed as shown in FIG. 4A.

In step (2), approach to the starting point node (a) is detected.

In step (2), the road map in the range including the starting point node (a) is read from the map memory [3].

In step (2), the read road map data is displayed on the entire screen as shown in FIG.
Convert to enlarged display format.

In step (2), the data converted into the enlarged display format is supplied to the second CPU (19). Thereby, the second CPU (19) writes the data converted into the enlarged display format into the frame memory (21) and displays it on the display (1).

In step ■, the node (n) to be guided next
Detect approaching.

In step ■, it is determined whether or not the approached node (n) is the end point node (b). If the end point node (b) is not, in step Month 3) is read out and the process of step 2 is performed. That is, the process of step (2) is sequentially repeated until the end point node (b) is reached.

On the other hand, if it is determined that the node (n) is the end point node (b) in the above step ■, then in step ■ the end point node (b) is displayed together with the destination on a wide road map At [phase], the processing flow ends.

According to the above guidance flow, from the current location to the starting point node (a) of the recommended route and the ending point node (b) of the recommended route to the destination, the vehicle position, starting point node (a), or destination is displayed together with the road map. By doing so, it is possible to grasp one's own position within a wide area, so it is useful when driving on city streets where the vehicle speed is relatively slow, or when driving on geographically unfamiliar streets. can.

In addition, from the starting point node (a) of the recommended route to the end point node (b) of the recommended route, each branch point is displayed in a form with good visibility, so you can drive at high speed like a car or a main road. - Can be used on roads where it is necessary to instantly judge the shape of a junction. In particular, at intersections with many branching roads, such as the one shown in Figure 4B, the optimal route is displayed enlarged along with the road map, making it easy to instantly see which road to choose. can. Therefore, the vehicle can be guided safely.

Furthermore, while driving, the road map and recommended route are rotated and displayed around the vehicle position, making it easy to check the direction of other roads relative to the direction of travel, which helps in selecting a route. It is convenient.

FIG. 9 shows an example of displaying complicated branch points using the route guidance of the above embodiment.

In order to make a right turn, it is necessary to proceed in the left lane.On a three-dimensional branch road where it is necessary to proceed in the left lane, it can be visually recognized that it is necessary to proceed in the left lane in advance (see FIG. 9A).

In the case of consecutive junctions, after passing the first intersection, the direction of travel for the next consecutive intersection is indicated, allowing the driver to prepare in advance and avoid the risk of confusion. (See Figure 9C).

At complex intersections such as in front of stations, the enlarged road map allows you to visually check the road configuration in front of the station, and also displays recommended routes, so you can avoid getting caught up in congestion in front of the station (Figure 9C) reference).

In addition, at a branch point with a simple shape, it is also possible to display only the direction along the recommended route.

<Effects of the Invention> According to the invention described above, the driver operates the initial setting means to set the destination and desired route calculation conditions, and the route calculation means calculates the route set by the initial setting means. By calculating the recommended route based on the conditions, the route desired by the driver can be provided. Then, this recommended route is stored in the storage means, and the vehicle guidance means
Each time the vehicle approaches a predetermined junction, a road map containing the approaching junction is read from the map memory and enlarged and displayed along with the current position and recommended route, making it easier to see the direction of travel and improving safety. This gives you the advantage of being able to drive more easily.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram of the in-vehicle navigator of the present invention, Fig. 2 is a block diagram showing an embodiment of the in-vehicle navigator of the invention, and Fig. 3 shows the hardware configuration of the route calculation section, main memory, and output controller. Figure 4 is a diagram showing the map display format, Figure 5 is a diagram showing the initial setting menu displayed on the screen, Figure 6 is a diagram showing the recommended route calculation flow, and Figure 7 is a diagram showing the route search area. FIG. 8 is a diagram illustrating the route guidance flow, and FIG. 9 is a diagram illustrating an example of displaying complicated branch points using the route guidance method of the above embodiment.

Claims (5)

[Claims] 1. From the combination of nodes and links road data and background data of buildings, etc. The location where the road map data consisting of data is stored a diagram storage means; A position detection means for detecting the vehicle position, Destination and route calculation desired by the driver initial setting means for inputting output conditions; Current location and destination from the above map storage means Read the road map data of the range including This road map data and initial setting means Recommendation based on route calculation conditions set by a route calculation means for calculating a recommended route; A storage means for storing the recommended route; Vehicle detected by the above position detection means Branching on the recommended route based on both location data Detects the approach to the point and the branch that approached Store road map data including points on the above map. Read from means, vehicle position, and recommended route Vehicle guidance means that enlarges and displays the road An in-vehicle navigation system characterized by having Data. 2. The initial setting means of claim 1 allows the driver to select any one route calculation condition from a plurality of route calculation conditions set based on the following evaluation function Fi, and also allows the driver to select one of the route calculation conditions set based on the following evaluation function Fi. An in-vehicle navigator characterized in that it allows the driver to change the value to a value desired by the driver. Fi=Σ(αmi×Am)...(I) (where, i is the number of route modes, Σ(αm)=1, and αm(m=1, 2,...n)
is the weighting index of Am and A is the attribute of the link) 3. The map storage means of claim 1 above is of a road type. Optimize the node spacing of the road data depending on the From the top layer map that is also widest to the narrowest categorize them into the lowest level maps. I remember it, The recommended route calculation means of claim 1 above comprises: Based on the straight-line distance from your current location to your destination. to set the route search area and perform route search. If the search areas are on the same level, Goal from node near current location within one hierarchy By adding the links leading to nodes near the ground, The route is calculated and the route search area is on the same floor. If it is not a layer, the lower layer and the upper layer Roads are interlayer connection nodes that connect layers. Search from network data to find nodes near your current location. from the node to the interlayer connection node at the current location. Route, from a node near the destination to the destination side The route to the interlayer connection node and the current From the layer connection node on the ground side to the layer on the destination side The current route is calculated by summing up the routes to the nodes From a node near your location to a node near your destination The method should calculate the route to the destination. An in-vehicle navigator featuring: 4. The route guidance means according to claim 1 is currently from the ground by the route calculation means of claim 3 above. The starting point of the recommended route calculated by Display the edge and vehicle position superimposed on the road map screen while driving the recommended route. Recommended route for the entire screen or window of the screen, Displays the vehicle position and the shape of the junction, From the end of the recommended route to the destination, Display destination and vehicle position on road map An in-vehicle navigator that is characterized by: 5. The route guidance means according to claim 1 is a road attributes, attributes of each branch point, driving Road maps and cars depending on the person's degree of unfamiliarity with the land Display of both positions, or recommended route, vehicle position display the location and shape of the branch point, or Road map, recommended route, vehicle location, and minutes Switch to a display that combines the shapes of junctions. An in-vehicle navigator that is characterized by: