JP2916295B2 - In-vehicle navigator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-vehicle navigator,
Particularly, the present invention relates to an in-vehicle navigator capable of displaying a large amount of map information useful for a driver on a screen.

[0002]

2. Description of the Related Art There is an on-vehicle navigator that provides guidance for driving a vehicle so that a driver can easily reach a desired destination. In this in-vehicle navigator, a vehicle position is detected, map data around the vehicle position is read from a CD-ROM, a map image is drawn on a V-RAM, and a vehicle position mark is superimposed on a predetermined position on the map image. Draw,
While converting the image in the V-RAM into a video signal, the image is output to a CRT display device and displayed on a screen. Then, as the current position changes as the vehicle moves, the vehicle position mark is fixed at the center of the screen and the map is scrolled, so that the map information around the vehicle position can always be understood at a glance.

A map stored in a CD-ROM is divided into regions of appropriate longitude and latitude widths according to the scale level, and roads are represented by vertices (nodes) represented by longitude and latitude coordinates. ). A portion connecting two or more nodes is called a link. Road data included in each map is, as shown in FIG. 11, road link data RLD.
T, node data NDDT, and intersection data CRDT. Among them, the road link data RLDT gives attribute information of the road link, and includes the total number of nodes on the link and the node data of each node constituting the link. It is composed of data such as numbers on the NDDT, road names, road types, and the like. The intersection data CRDT is, for each intersection on the map, a set of numbers on the node data NDDT of nodes closest to the intersection on the link connected to the intersection (referred to as an intersection configuration node).
DDT is a list of all nodes on the map, coordinate information (longitude, latitude) for each node, an intersection identification flag indicating whether or not the node is an intersection, and indicates intersection data if the node is an intersection; It is composed of a pointer or the like indicating the road link to which the node belongs.

Some of such in-vehicle navigators have a route guidance function of providing route guidance along an optimal guidance route from a departure point to a destination. In such route guidance,
If the driver sets the departure point and destination before traveling, the CD-
A simulation calculation is performed with reference to the map data in the ROM, and for example, an optimal guide route connecting the departure place and the destination at the shortest distance is obtained, and a node sequence constituting the guide route, the starting departure place data at the head and the tail end The guidance route data combined with the destination data is stored in the guidance route memory.

During driving, the driver searches for a guidance route in the map display area of the screen from the node sequence in the guidance route memory and displays the guidance route in a different color from other roads. Is trying to figure out which road to drive.

[0006] By the way, among the maps displayed on the screen, the map information of the direction in which the vehicle is going to travel is effective for the driver.
As shown in FIG. 12, the center of the screen is the vehicle position, and the effective map information given to the driver is only half of the screen.

[0007] To avoid this disadvantage, a point spaced a certain distance L ₀ towards the vehicle position to the destination direction and the display center of the screen, or (real Hei to give a lot of map information of interest local surface 1 see JP -128121), or a point separated by a predetermined distance L ₀ from the vehicle position in the vehicle traveling forward with the display center of the screen, proposals have been made to provide a lot of map information of the vehicle traveling direction.

[0008]

However, in the former case, it is good if the currently traveling road extends toward the destination as shown in FIG. 13 (1). As shown in FIG. 13 (2), in many cases, a currently traveling road extends in a direction greatly different from a destination direction to bypass a mountain or the like, and in such a case, a display range of a direction in which a vehicle is going to travel is changed. On the contrary, there is a problem that the map becomes narrow and only a small amount of necessary map information can be obtained. Similarly, in the latter case, as shown in FIG. 14A, it is good if the vehicle travels on a long straight road. , FIG.
As shown in FIG. 4 (2), when the course is changed a little ahead of the vehicle position, the display range of the area where the vehicle is going to travel is rather narrowed, and only a small amount of necessary map information can be obtained. was there.

Accordingly, an object of the present invention is to provide an in-vehicle navigator capable of always providing a large amount of useful map information to a driver.

[0010]

According to the present invention, there is provided a map data storage means for storing map data; a display means for displaying a map image; a vehicle position detection means for detecting a vehicle position; Means for searching for the optimal guide route from the departure point to the destination by referring to
In the in-vehicle navigator including the above, of the intersections present on the guidance route, the first route change intersection located at the forefront when viewed closer to the destination than the vehicle position and the second route change intersection located second at the front Route change intersection searching means for finding
When the course change intersection exists and the distance between the vehicle position and the first course change intersection exceeds a predetermined fixed distance, a predetermined fixed distance from the vehicle position on a straight line connecting the vehicle position and the first course change intersection. A point near the first course change intersection is determined and set as a display center point. If the first and second course change intersections exist and the vehicle position and the first course change intersection are within a predetermined fixed distance, the vehicle position and the first A point closer to the second route change intersection by a predetermined distance from the vehicle position on a straight line connecting the two route change intersections is determined as a display center point, and in other cases, the vehicle position is determined by a straight line connecting the vehicle position and the destination. A display center point calculating means for obtaining a point closer to the destination by a predetermined fixed distance as a display center point, and superimposing a vehicle position mark on the map image such that the center of the screen becomes the display center point based on the map data. A map display control means for displaying on the shown means, is achieved by a provided.

[0011]

According to the present invention, of the intersections existing on the guidance route, a first course change intersection located closest to the destination when viewed closer to the destination than the vehicle position, and a second route change intersection located second ahead of the vehicle. A route change intersection is determined, and if the first route change intersection exists and the vehicle position and the first route change intersection exceed a predetermined fixed distance, the vehicle is drawn on a straight line connecting the vehicle position and the first route change intersection. A point closer to the first course change intersection by a predetermined distance from the position is determined as a display center point, and the first and second course change intersections are present, and the distance between the vehicle position and the first course change intersection is within a predetermined distance. In the case, a point closer to the second route change intersection by a predetermined distance from the vehicle position on a straight line connecting the vehicle position and the second route change intersection is determined as a display center point,
In other cases, a point closer to the destination by a predetermined distance from the vehicle position on a straight line connecting the vehicle position and the destination is determined as the display center point, and the center of the screen is set to the display center point based on the map data. To display the vehicle position mark on the map image on the display means. As a result, regardless of whether the currently traveling road is extending toward the destination or whether it is a long straight road, the vehicle always drives a large amount of map information in the direction that the vehicle will travel. Can be given to the person.

[0012]

FIG. 1 is a block diagram of a main part of an on-vehicle navigator according to the present invention.

In FIG. 1, reference numeral 1 denotes a C storing map data.
D-ROM 2 is an operation panel, and includes left, right, up, and down cursor keys, a route guidance mode setting key, a departure place setting key, a destination setting key, a key for map search, enlargement / reduction,
A start key and the like are provided. Reference numeral 3 denotes a vehicle position detecting unit that has a direction sensor and a distance sensor, detects the position and direction of a running vehicle by integral navigation, and outputs vehicle position data and vehicle direction data, and 4 denotes a CRT display device.
A video signal is input, and a map is displayed on a screen together with a cursor mark, a vehicle position mark, an enhanced guidance route, and the like.

Numeral 10 denotes a navigation controller, which determines an optimum guidance route from a departure point and a destination by simulation calculation, and displays a map image around the vehicle position together with a cursor mark, a vehicle position mark, and an enhanced guidance route as necessary. It is displayed on the screen of the CRT display device 4.

Among them, reference numeral 11 denotes a buffer memory for temporarily storing map data read from the CD-ROM 1;
Reference numeral 2 denotes a cursor position calculation unit, which displays a longitude corresponding to the center of the map on the screen when a map selection operation or a cursor operation is performed using a cursor key on the operation panel 2, a key for map search, an enlargement / reduction key, or the like. Calculate latitude and output as cursor position. Reference numeral 13 denotes a map drawing control unit, which stores desired map data (may include surrounding map data) selected by a key for map search, enlargement / reduction, etc. on the operation panel 2 before starting traveling. The map data is read from the ROM 1 to the buffer memory 11 and a map image is drawn on a V-RAM, which will be described later. As the cursor position input from the cursor position calculator 12 changes in accordance with the cursor operation, new map data is necessary. While reading from the CD-ROM 1 to the buffer memory 11, the map image in the V-RAM is rewritten so that the cursor position is always at the center, and the VR
Draw a cursor mark at the center of the AM. Further, while traveling in the route guidance mode (after the start key of the operation panel 2 is pressed), the map drawing control unit 13 adds a new display center point data as necessary as the display center point data output from the display center point calculation unit described later changes. While reading out the appropriate map data from the CD-ROM 1 to the buffer memory 11, the map image in the V-RAM is rewritten so that the display center point becomes the center. In addition, the map drawing control unit 13 draws a vehicle position mark in a predetermined location of the V-RAM in a predetermined direction based on the vehicle position data and the vehicle azimuth data while the vehicle is running. From the guidance route data stored in the memory, guidance route data that falls within the range of the map image currently rendered in the V-RAM is input, and the guidance route highlighted in a color different from other roads is drawn. .

Reference numeral 14 denotes a departure / destination setting unit, which is set to a route guidance mode by the operation panel 2 before starting traveling. After the cursor at the center of the screen is matched with the departure point by operating the operation panel 2, When the departure point setting key is pressed, the output of the cursor position calculation unit 12 at that time is set as departure point data, and after the cursor at the center of the screen matches the destination by operating the operation panel 2, the destination is output. When the setting key is pressed, the output of the cursor position calculator 12 at that time is set as destination data.

Reference numeral 15 denotes a guide route search unit, which inputs departure place data and destination data from the start place / destination setting unit 14 when a start place and a destination are set in the route guide mode. , Read various map data from the starting point to the destination from the CD-ROM 1 to the buffer memory 11 and perform simulation calculations on various routes with reference to the read map data, for example, using the shortest distance as an index, An optimal guide route from the departure point to the destination is determined, and a series of node trains (each node includes longitude and latitude coordinates and an intersection identification flag R indicating whether or not the intersection is included) constituting the guide route. Along with the departure place data and the destination data, it is stored in a later-described guidance route memory as guidance route data. Each node in the node sequence is extracted from a node list of map data (see NDDT in FIG. 11).

Reference numeral 16 denotes a guidance route memory for storing guidance route data. The node sequence obtained by the guidance route searching unit 15 is, for example, 16 except for the departure place data and the destination data.
³ when composed -2 nodes, as shown in FIG. 2, the departure point data is stored in the address F000 _H, address F
001 _H ~FFFE The _H, closest node departure on the guide route to the address F001 _H, address F002 _H
The node sequence is sequentially stored in the order of the node closest to the departure place on the guidance route. Then, the destination data is stored at the end of the address FFFF _H. The guidance route memory 16 also stores a route change intersection identification flag S indicating whether or not the route change intersection exists for each node.

Reference numeral 17 denotes a course change intersection detecting unit which searches for a course change intersection by referring to the guide route data stored in the guide route memory 16 after the search of the guide route is completed.
Set the course change intersection identification flag S. Here, diversion intersection, among the nodes series comprising the guide route, a node N _i intersection identification flag is set, and enters the node N _i-1 of the previous and one on node series between the exit node N _{i + 1} after, as shown in FIG. 3, the reference direction the half line that extends to the ingress node N _i-1 direction from the node N _i,
When the angle θ of the escape node N _{i + 1} is obtained in the clockwise direction, the angle θ is obtained assuming that the relationship of 0 ≦ θ ≦ 135 ° or 225 ° ≦ θ <360 ° holds.

Then, while traveling in the route guidance mode, the route change intersection detection unit 17 refers to the guidance route memory 16 and
Among the intersections present on the guidance route, a first course change intersection located closest to the destination as viewed closer to the destination than the vehicle position and a second course change intersection located second ahead are determined.

Reference numeral 18 denotes a display center point calculating unit. The first course change intersection with respect to the current vehicle position is detected by the course change intersection detecting unit 17 during traveling in the route guidance mode, and the vehicle position and the first course change are detected. display between intersections if exceeds the predetermined constant distance L _s, to calculate the location of the predetermined distance L ₀ by a first diverter intersection closer than the vehicle position on a straight line connecting the vehicle position and the first diverter intersection A central point,
First and second diverter intersection is detected, if between the vehicle position and the first diverter intersection is within L _s, the vehicle position and the second course change to the current vehicle position at the course change crossing detector 17 A point closer to the second course change intersection by L ₀ from the vehicle position on the straight line connecting the intersection is determined as the display center point. In other cases, the destination is shifted by L ₀ from the vehicle position on the straight line connecting the vehicle position and the destination. The map drawing control unit 13 obtains a near point and sets the display center point data as the display center point.
Output to

Reference numeral 19 denotes a V-RAM, which is a map image drawn by the map drawing control unit 13 (including a cursor mark when the cursor is operated before the start of driving, and a vehicle position mark when driving in the route guidance mode). (Including an enhanced guidance route that is different in color from other roads). Reference numeral 20 denotes a video conversion unit that converts the image data output from the V-RAM 19 into a video signal and outputs the video signal to the CRT display device 4.

FIGS. 4 to 6 are flowcharts showing the operation of the navigation controller 10, FIG. 7 is an explanatory diagram showing the whole map from the departure point to the destination, and FIGS. 8 to 10 are display screens of the CRT display device 4. Are described below, and the description will be made with reference to these figures.

First, when an operation of selecting a map of a desired area at a desired scale is performed by operating a map search, an enlargement / reduction key or the like on the operation panel 2, the map drawing control unit 13 reads the desired map from the CD-ROM 1. The data is read out to the buffer memory 11 and a map image is drawn on the V-RAM 19. VR
The map image data drawn on the AM 19 is transferred to the video conversion unit 20.
Is converted into a video signal and output to the CRT display device 4. The CRT display device 4 displays a map on the screen based on the input video signal (step 10 in FIG. 4).
1, 102). Subsequently, when a cursor key of the operation panel 2 is operated after the setting operation of the route guidance mode is performed on the operation panel 2, the cursor position calculation unit 12 calculates the cursor position (longitude and latitude coordinates) (step S1). 103-10
6) In accordance with the change in the cursor position, the map drawing control unit 13 draws a map image in the V-RAM 19 while reading predetermined map data from the CD-ROM 1 into the buffer memory 11 so that the center is always the cursor position. At the same time, a cursor mark is drawn at the center of the V-RAM 19. As a result, the map on the screen moves in accordance with the cursor operation while the cursor mark is displayed at the center of the screen (steps 107 and 108).

When the cursor operation is temporarily stopped and the destination setting key on the operation panel 2 is pressed when the cursor mark on the screen reaches the destination, the departure / destination setting unit 14 causes the cursor position calculation unit 12 at that time. Is set and registered as destination data (steps 109 and 110). Subsequently, the cursor is operated again to move the map on the screen. When the cursor mark reaches the departure place, the cursor operation is temporarily stopped, and the departure place setting key of the operation panel 2 is pressed. Part 1
4 sets and registers the cursor position data output from the cursor position calculator 12 at that time as departure point data (steps 111 and 112). Here, it is assumed that the relationship between the starting point and the destination on the map is as shown in FIG.

Thus, when the setting and registration of the departure place data and the destination data are completed (YES in step 113)
The guide route search unit 15 repeats the simulation calculation while reading the map data from the departure point to the destination from the CD-ROM 1 to the buffer memory 11 based on the departure point data and the destination data, and indicates, for example, the shortest distance. The optimal guide route is searched for, and a series of nodes forming the guide route is stored in the guide route memory 16 together with the leading departure point data and the last destination data (steps 201 and 202 in FIG. 5). ). At this time, each node data stored in the guidance route memory 16 includes longitude and latitude coordinates and an intersection identification flag R. When there are 16 ³ -2 nodes (excluding the departure point data and the destination data) constituting the guidance route, the guidance route data stored in the guidance route memory 16 is as shown in FIG. Here, it is assumed that the guidance route is as shown by a broken line in FIG.

When the search for the guidance route and the storage of the guidance route are completed, the course change intersection detecting unit 17 returns to the guidance route memory 1.
6, the route change intersection is searched for from the intersection nodes where the intersection identification flag R is set on the basis of the positional relationship between the entry node and the exit node with respect to the intersection node, and the corresponding route change intersection identification flag S is set (step). 20
3). Here, it is assumed that the intersection nodes CA and CB are route change intersections in the guidance route indicated by the broken line in FIG.

Next, when the vehicle starts running after pressing the start key on the operation panel 2, the vehicle position detecting section 3 moves the vehicle by a predetermined distance starting from the departure place data previously set by the departure place / destination setting section 14. Each time the vehicle travels, the vehicle position and the vehicle direction are detected, and the vehicle position data and the vehicle direction data are output to the map drawing control unit 13, and the vehicle position data is output to the course change intersection detection unit 17 and the display center point calculation unit 18. (Steps 204 and 205). The course change intersection detecting unit 17 receives the vehicle position data and inputs the vehicle position data to the guidance route memory 1.
6, the route change intersection identification flag S is set up, and the nearest node as viewed from the vehicle position toward the destination is the first route change intersection CP1, the second closest. Is determined as the second route change intersection CP2 (step 206), and the coordinate data of each of the first and second route change intersections is output to the display center point calculation unit 18. Here, first, the intersection node CA in FIG. 7 is the first route change intersection CP1 and the CB is the second route change intersection CP2.

Next, based on the data input from the course change intersection detecting section 17, the display center point calculating section 18 first judges whether the course change intersection detecting section 17 has detected the first course changing intersection (step 207). Since YES, the current vehicle position and the first course change intersection CP1
= The distance between the CA computes, determines whether a predetermined fixed distance L _s above a predetermined (step 208). Again Y
At the time of ES, the display center point calculation unit 18 determines a predetermined predetermined value from the vehicle position on a straight line connecting the current vehicle position and the first course change intersection CP1 = CA (see SH1 in FIG. 8A). The first course change intersection CP for a fixed distance L ₀ (here, L _s > L ₀ is set in advance)
The next point is calculated and output to the map drawing control unit 13 as display center point data (step 209).

Upon input of the display center point data, the map drawing control unit 13 converts the map data around the display center point into a CD.
-While reading from the ROM 1 to the buffer memory 11, a map image is drawn on the V-RAM 19 so that the center coincides with the point indicated by the display center point data (step 301 in FIG. 6), and then stored in the guidance route memory 16. Of the guidance route data obtained, the nodes (here, including the departure place data) in the map drawing area of the V-RAM 19 are read out, and based on these data, a color different from other roads is displayed on the V-RAM 19. Then, an enhanced guidance route for route guidance is drawn (step 302). Then, based on the vehicle position data and the vehicle azimuth data input from the vehicle position detection unit 3, the vehicle position mark is drawn with the direction indicated by the vehicle azimuth data directed to a location corresponding to the vehicle position on the map drawn in the V-RAM19. (Step 303).

The image drawn on the V-RAM 19 is output to the CRT display device 4 while being converted into a predetermined video signal by the video converter 20, and is displayed on the screen. As a result, a map image around the vehicle position is displayed on the screen so that the display center point previously obtained by the display center point calculation unit 18 is located at the center (see FIG. 8A). First, the vehicle position mark CM on the screen is displayed at the place of departure. At this time, the vehicle position on the screen is shifted from the center to the first course change intersection CP1 =
Since the vehicle is on the opposite side of the CA, even if the direction of the destination does not match the direction of the first course change intersection CP1 = CA when viewed from the vehicle position (see FIG. 7), the direction in which the vehicle will travel from now on A lot of map information will be given to the driver. In addition, since the guidance route is displayed in a color different from that of the other roads, it is possible to know at a glance which road to travel along.

When the vehicle travels for a certain distance, the vehicle position detecting section 3 calculates a new vehicle position and vehicle direction, and outputs vehicle position data and vehicle direction data (step 20 in FIG. 5).
5). Then, the course change intersection detector 17 detects the first course change intersection C for the new vehicle position in the same manner as described above.
A search is made for P1 and the second course change intersection CP2, and the result is output to the display center point calculation unit 18 (step 206). Here, the mileage is still short, and the first course change intersection CP1 =
CA, and remains in the second diverter intersection CP2 = CB, the distance between the vehicle position and the CP1 also intended that there more than L _s. Subsequently, the display center point calculating unit 18 calculates the display center point of the L ₀ only CP1 Towards vehicle position on a straight line connecting the new vehicle position and the first diverter intersection CP1 in the same manner as described above, the map drawing control Output to the unit 13 (steps 207 to 207).
209). Upon input of the new display center point data, the map drawing control unit 13 reads predetermined map data including the display center point from the CD-ROM 1 into the buffer memory 11 while the center becomes the display center point on the V-RAM 19. After the map image is drawn and the guide route included in the drawn map area is emphasized, the vehicle position mark is drawn in a direction corresponding to the new vehicle position in the direction indicated by the new vehicle direction ( Steps 301 to 30 in FIG.
3). The image newly drawn on the V-RAM 19 is output to the CRT display device 4 while being converted into a predetermined video signal by the video conversion unit 20. Thereby, the vehicle position mark on the screen slightly approaches the first course change intersection CP1 = CA (the vehicle position mark on the screen shows the first course change intersection C).
P1 = CA appears to approach).

Hereinafter, the same processing is repeated every time the vehicle travels a certain distance. After a while, the screen is
It looks like (2). Then, after the vehicle has approached to a certain distance L _s to the first diverter intersection CP1 = CA (FIG. 8
(See (3)) Further, when the vehicle further travels a little, the display center point calculation unit 18 determines NO in step 208 of FIG. At this time, the display center point calculation unit 18 determines whether the second route change intersection CP2 for the current vehicle position is detected based on the data input from the route change intersection detection unit 17 (step 210). CB
When There is to be present, the display center point of the L ₀ only CP2 Towards the vehicle position calculated in the vehicle position and the straight line connecting the second course change intersection CP2 (see SH2 in FIG. 9 (1)), the display center The point data is output to the map drawing control unit 13 (step 211).

When the map drawing control unit 13 inputs new display center point data, predetermined map data including the display center point is read from the CD-ROM 1 to the buffer memory 11 while the center is displayed on the V-RAM 19. After drawing the map image to be a point and emphasizing the guidance route included in the drawn map area, the vehicle position mark is superimposed on the position corresponding to the new vehicle position in the direction of the new vehicle direction. Drawing (Steps 301 to 30 in FIG. 6)
3). The image newly drawn on the V-RAM 19 is output to the CRT display device 4 while being converted into a predetermined video signal by the video conversion unit 20. As a result, the screen shown in FIG.
Since the vehicle position changes as shown in (1) and the vehicle position on the screen is on the opposite side of the second course change intersection CP2 (= CB) from the center, the course of the guidance route is largely changed slightly ahead of the vehicle position. Even so, a large amount of map information for the area where the vehicle will travel will be given to the driver.

Thereafter, when the vehicle travels and crosses the intersection CA, the first route change intersection CP1 detected by the route change intersection detecting unit 17 at step 206 in FIG. 5 becomes CB (see FIG. 7). , The second course change intersection CP2 cannot be detected, so the course change intersection detection unit 1
7 outputs only the first course change intersection data to the display center point calculation unit 18. At this time, the display center point calculation unit 18 first determines whether or not the first course change intersection CP1 exists (step 207).
The distance to the course change intersection CP1 = CB determines whether there or L _s (step 208). If there above L _s, the display center point calculating unit 18 vehicle position and the first diverter intersection C
P1 = only L ₀ from the vehicle position on a straight line connecting the CB CP1
The display center point is calculated and the display center point data is output to the map drawing control unit 13 (step 209). Therefore, the screen is as shown in FIG. 9 (2), and since the vehicle position on the screen is located on the opposite side of the first course change intersection CP1 = CB from the center, the map information of the area where the vehicle is about to travel is also obtained. Is often given to drivers.

The traveling of the vehicle further proceeds, and the vehicle changes its first course.
Further intersection CP1 = Constant distance L to CB _sAfter approaching
(Refer to FIG. 10 (1)).
The indicated center point calculation unit 18 returns NO in step 208 of FIG.
to decide. At this time, the display center point calculating unit 18 changes the course.
Based on the data input from the new intersection detector 17,
Intersection change point CP2 for the vehicle position is detected
Is determined (step 210).
Therefore, the vehicle position and the eye read from the guidance route memory 16
On a straight line connecting the destinations (see SH3 in FIG. 10 (2))
L from position₀Only calculate the display center point near the destination,
Outputs display center point data to the map drawing control unit 13
(Step 212).

When new map center point data is input, the map drawing control unit 13 reads out predetermined map data including the display center point from the CD-ROM 1 into the buffer memory 11 and places the center of the display center on the V-RAM 19. After drawing the map image to be a point and emphasizing the guidance route included in the drawn map area, the vehicle position mark is superimposed on the position corresponding to the new vehicle position in the direction of the new vehicle direction. Drawing (Steps 301 to 30 in FIG. 6)
3). The image newly drawn on the V-RAM 19 is output to the CRT display device 4 while being converted into a predetermined video signal by the video conversion unit 20. As a result, the screen is
0 (2), the vehicle position comes to the opposite side of the destination from the center on the screen, and a large amount of map information on the destination local area is given to the driver. When there is no second turnaround intersection for the current vehicle position, the vehicle is close to the destination and the map information on the screen is useful to the driver.

Thereafter, when the vehicle travels and the vehicle turns around the intersection CB, at step 206 in FIG.
The course change intersection detector 17 is a first course change intersection CP1.
Also cannot be detected. Then, the display center point calculation unit 18 determines in step 207 that the first course change intersection CP1 does not exist, and the vehicle center and the destination read from the guidance route memory 16 are shifted from the vehicle position in the same manner as described above. the display center point of the destination near calculated by L _0, and outputs a display center point data to the map drawing control unit 13 (step 212). Therefore, the screen is as shown in FIG. 10 (3), and since the vehicle position on the screen is located on the opposite side of the destination from the center, the map information for the area where the vehicle is going to travel is given to the driver. Can be

According to this embodiment, irrespective of whether or not the road on which the vehicle is currently running extends toward the destination, and whether or not the course is to be changed a little ahead of the vehicle position, It is possible to always provide the driver with a large amount of map information on the direction in which the vehicle will travel.

In the embodiment described above, L _s > L ₀ , but L _s = L ₀ may be set. Although the vehicle position is detected by integral navigation, the vehicle position may be detected by satellite navigation using GPS or the like, and the detected vehicle position may be corrected by map matching. Further, the map drawing control unit redraws the map image in the V-RAM every time the display center point changes. However, the map drawing control unit draws a map image of a certain wide area around the vehicle position in the V-RAM. In accordance with the change of the display center point, if one screen with the display center point as the center is cut out from the V-RAM,
The number of times a map image is drawn on the V-RAM can be reduced. In addition to setting the destination by moving the cursor,
Register the hotel name, place name, station name, hot spring name, ski resort name, golf course name, etc. together with longitude and latitude coordinates as service data in the D-ROM, and drive from the service menu displayed on the screen When a person selects a destination name,
The position of the destination may be automatically set.

[0041]

As described above, according to the present invention, of the intersections existing on the guidance route, the first course change intersection located closest to the destination as viewed from the vehicle position and the second route change intersection located closest to the destination. If the first route change intersection exists and the vehicle position and the first route change intersection exceed a predetermined distance, a straight line connecting the vehicle position and the first route change intersection is obtained. A point closer to the first course change intersection by a predetermined fixed distance from the vehicle position is determined above as the display center point,
When the second route change intersection exists and the distance between the vehicle position and the first route change intersection is within a predetermined fixed distance, a predetermined fixed distance from the vehicle position on a straight line connecting the vehicle position and the second route change intersection. A point near the intersection for changing the binary route is determined and set as the display center point. In other cases, a point closer to the destination by a predetermined fixed distance from the vehicle position on a straight line connecting the vehicle position and the destination is determined and set as the display center point. Based on the data, the vehicle position mark is superimposed on the map image and displayed on the display means so that the center of the screen becomes the display center point, so that the currently traveling road extends toward the destination. No matter whether it is a long straight road or not,
It is possible to always provide the driver with a large amount of map information on the direction in which the vehicle will travel.

[Brief description of the drawings]

FIG. 1 is a main block diagram of an in-vehicle navigator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of data stored in a guidance route memory of FIG. 1;

FIG. 3 is an explanatory diagram illustrating an operation of a course change intersection detecting unit in FIG. 1;

FIG. 4 is a flowchart showing an operation of the navigation controller of FIG. 1;

FIG. 5 is a flowchart showing an operation of the navigation controller of FIG. 1;

FIG. 6 is a flowchart showing an operation of the navigation controller of FIG. 1;

FIG. 7 is an explanatory diagram showing an overall image of a map including a departure place and a destination.

FIG. 8 is an explanatory diagram showing a screen display example of the CRT display device of FIG. 1;

FIG. 9 is an explanatory diagram showing a screen display example of the CRT display device of FIG. 1;

FIG. 10 is an explanatory diagram showing a screen display example of the CRT display device of FIG. 1;

FIG. 11 is an explanatory diagram showing a configuration of road data in map data.

FIG. 12 is an explanatory diagram of a display screen in a conventional general vehicle-mounted navigator.

FIG. 13 is an explanatory diagram of a display screen in another type of conventional vehicle-mounted navigator.

FIG. 14 is an explanatory diagram of a display screen in still another type of in-vehicle navigator of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CD-ROM 3 Vehicle position detection part 4 CTR display device 10 Navigation controller 13 Map drawing control part 15 Guidance route search part 16 Guidance route memory 17 Route change intersection detection part 18 Display center point calculation part

Claims (1)

(57) [Claims] 1. A map data storage means for storing map data, a display means for displaying a map image, a vehicle position detection means for detecting a vehicle position, and an optimal distance from a departure point to a destination by referring to the map data. A guidance route search means for finding a suitable guidance route, a first route change intersection located at the foreground when viewed closer to the destination than the vehicle position, among the intersections existing on the guidance route; In the case where the route change intersection searching means for finding the second route change intersection located in the front and the first route change intersection are present and the distance between the vehicle position and the first route change intersection exceeds a predetermined fixed distance, On a straight line connecting the vehicle position and the first route change intersection, a point closer to the first route change intersection by a predetermined distance from the vehicle position is determined as a display center point, and the first and second route change intersections are present, and the vehicle position is determined. And the second When the distance between the first track change intersections is within a predetermined distance, a point closer to the second track change intersection by a predetermined distance from the vehicle position on a straight line connecting the vehicle position and the second track change intersection is determined as a display center point. In other cases, based on map data, display center point calculating means for determining a point closer to the destination by a predetermined constant distance from the vehicle position on a straight line connecting the vehicle position and the destination and as a display center point, and map data,
An on-vehicle navigator comprising: map display control means for superimposing a vehicle position mark on a map image and displaying it on a display means such that the center of the screen is a display center point.