JPH0944085A - Navigation device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display map in a wide range for all directions centering around the present position without losing the continuity of a road. SOLUTION: A coordinate of a node on a link constituting a map is transformed to polar coordinates (r, θ) by a straight distance r between the present position of a vehicle and the node and angle θ of the node direction to the traveling direction of the vehicle (step 103), and the distance r is transformed to a distance R using the logarithmic function so that the variation rate of the distance is made small as the distance becomes large (step 104). Polar coordinates of each node is set to (Rcosθ, Rsinθ) using the transformed distance R and the angle θ (step 15), display data of a map is made using these polar coordinates, and a map is displayed at a display position (step 106). Thereby, a map in which a reduction scale is made continuously large as the distance from the present position becomes large in the circumferential direction making the present position as the origin can be displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular navigation device that displays a vehicle's current location and a map.

[0002]

2. Description of the Related Art Various devices of this type have been proposed which display a current position and a map on a display screen. In these cases, the size of the display screen is limited, so when displaying a map with a reduced scale, only the area in the vicinity where the vehicle is currently traveling can be displayed, and the road shape outside the display area cannot be displayed. I can't know what is going on. Also, when the scale of the map is enlarged to display a wide area, it is necessary to omit the detailed portion of the map and display it. There is a problem that you can not.

[0003]

On the other hand, Japanese Patent Application Laid-Open No. Sho 5
Japanese Patent Laid-Open No. 9-216016 discloses a detailed map of the vicinity where the vehicle is currently traveling, which is displayed on the upper right of the display screen as an enlarged view with a small scale. However, since different scale maps are displayed simultaneously on the same screen, there is no continuity between the roads displayed between the two maps,
The readability of the map deteriorates.

A bird's-eye view display for displaying a map viewed from the sky has also been proposed, but this one is capable of grasping a wide range of road shapes in front of the vehicle, but in the lateral direction it is different from the case of a normal map display. Since they are almost the same, the same problem as above occurs with respect to the lateral road shape. The present invention has been made in view of the above problems, and an object of the present invention is to display a wide range in all directions without impairing the continuity of a road.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, claims 1 to 3 are provided.
The invention described in (1) is characterized in that a map whose scale is continuously increased as the distance from the current position increases in the circumferential direction with the current position as the origin is displayed. Therefore, since the map is displayed by continuously increasing the scale, the continuity of the displayed road is not impaired, and the map is displayed in a wide range in all directions with the current position as the origin. be able to.

The inventions of claims 4 and 5 are characterized in that the change rate of the scale is changed. Therefore, the display range can be changed, and when the scale change rate is changed according to the distance between the current position and the destination as described in claim 5, the current position and the destination are included. The display range can be set.

The invention according to claim 6 is characterized in that the display density of the map is reduced in the display area where the distance from the current position is a predetermined distance or more.
Therefore, by reducing the display density in the display area of a predetermined distance or more, it is possible to make the display in that area easy to see.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention shown in the drawings will be described. FIG. 1 shows the overall configuration of a vehicle navigation device showing an embodiment of the present invention. In this embodiment, in order to detect the current position of the vehicle, the GPS
The receiver 1, the direction sensor 2, and the wheel speed sensor 3 are provided. The GPS receiver 1 receives a radio wave from an artificial satellite and outputs a signal indicating the current position of the vehicle. The direction sensor 2 detects the traveling direction of the vehicle and outputs a direction signal. The wheel speed sensor 3 outputs a distance signal according to the traveling distance of the vehicle based on the rotation speed of the wheel.

The storage device 4 stores a map data and the like C
It has a storage medium such as a DROM and outputs map data and the like to the control device 6. The operation unit 5 is operated by a vehicle occupant or the like and outputs various operation signals necessary for navigation.
The control device 6 is configured to include computer means such as a microcomputer, and executes arithmetic processing or the like for displaying a map including the current position of the vehicle on the display device 7 in response to signals from the above-mentioned respective constituent elements 1 to 5. To do. The map display data created by this arithmetic processing is stored in the video RAM (V-RAM) in the control device 6, and the map is displayed on the display device 7 by the stored display data.

The display device 7 is provided in the instrument panel portion of the vehicle and displays the above-mentioned map. A liquid crystal display device, a CRT display device, or the like can be used as the display device 7. In this embodiment, each road in the map is divided into a plurality of nodes (map constituent points) such as intersections, and each node is defined as a link.
A map is constructed and displayed by connecting links.

Therefore, the map data stored in the storage device 4 includes, for each link, a unique number (link ID) for identifying the link and the start and end nodes of the link, as shown in FIG. And link information composed of data of X type, Y coordinate, and type of road (indicating type of road such as narrow street, main road, main local road). Then, by using the connection information for connecting each link, each link is connected and displayed to form a map. The connection display using such a link is the same as that conventionally performed.

In the present embodiment, the scale of the map is reduced in the vicinity of the point where the vehicle is currently traveling to form a detailed road shape, and the scale of the map is continuously increased toward the farther distance to display a wide range of roads. I am trying to do it. The arithmetic processing of the control device 6 that performs such display control will be described based on the flowchart shown in FIG.

First, the current position of the vehicle is detected using the signals from the GPS receiver 1, the direction sensor 2 and the wheel speed sensor 3 (step 101). Next, the map data of the corresponding map including the current position of the vehicle is read from the storage device 4 based on the current position of the vehicle (step 102). Based on the read map data, the connection point of each link forming the map, that is, the coordinates of the node (the coordinates of the start end or the end of FIG. 2) and the coordinates indicating the current position of the vehicle detected in step 101 Distance r between the current position of the node and the node and the angle θ of the node direction with respect to the traveling direction of the vehicle
Is calculated and the coordinates of the node are converted into polar coordinates (r, θ) (step 103). The traveling direction of the vehicle can be obtained from the signal from the direction sensor 2. By the processing in step 103, the coordinates of each node are converted into polar coordinates with the current position of the vehicle as the origin.

Next, the distance r in polar coordinates is converted into the distance R using a logarithmic function so that the change rate of the distance decreases as the distance r increases (step 10).
4). Equation 1 is used as the logarithmic function.

[0015]

## EQU1 ## R = A × ln (r / A + 1) where A is a normalization coefficient, and what is the change rate of the position on the map display depending on the distance from the current position of the vehicle. The value is determined by. The distance R converted in step 104 and the angle θ obtained in step 103
Then, the coordinates of each node are set to (R cos θ, R sin θ) (step 105). Therefore, step 10
By the processes of 3 to 105, the coordinates of each node are converted into the coordinates represented by (R cos θ, R sin θ) with the current position of the vehicle as the origin. Since the node direction θ with respect to the current position does not change, the angular relationship between the current position and the node does not change.

From the converted coordinates and the link connection information, the respective nodes are connected to create display data for displaying a map, and the map is displayed on the display device 7 (step 106). The process shown in FIG. 3 is performed every predetermined time or each time the vehicle travels a predetermined distance.

In the above-mentioned processing, by using the logarithmic function of Equation 1, the change in distance on the map display becomes constant near the current position of the vehicle (the inclination at the origin is 1),
The farther away, the smaller the change in distance on the map display (the slope at infinity is 0). For example, A = 200
In the case of, the range of 30 m is displayed at a constant scale (within 10%).

FIG. 4 shows a display example when a grid-shaped map where roads intersect at intervals of 50 m is subjected to coordinate conversion using the logarithmic function. In normal display, there are 2 roads 500m ahead
It is displayed at a position of 50 m. In addition, by performing the same coordinate conversion for the display positions of landmarks / various facility names on maps other than roads, the map display scale is reduced as the distance from the vehicle's current position (origin) increases. Can be expressed as if

FIG. 5 shows an example of the map displayed by the above embodiment. (Second Embodiment) In the first embodiment described above, the scale of the map is increased as the distance from the current position of the vehicle is increased. However, in the second embodiment, the scale of the map is increased. It is changed according to the distance between the current position of the vehicle and the set destination.

FIG. 6 is a flowchart showing the main part arithmetic processing of the control device 6 in the second embodiment. After step 103 in FIG. 3, it is determined whether a destination is set (step 107). That is, it is determined whether or not the destination is set by the destination setting operation of the operation unit 5. The destination setting is performed in the same manner as the conventional setting.

When the destination is set, the normalization coefficient A is set (step 108). In this case, using Equation 1, R is calculated from the range of the displayed map, and the normalization for displaying the destination on the displayed map from the current position of the vehicle and the distance between the destinations (calculated from the respective coordinates) r. Obtain the coefficient A. For example, when the range of the normal display map is 2 km square, the distance from the current position to the end of the display screen is 1000 m (= R) when the conversion of FIG. = A × ln
A for which (r / A + 1) holds is obtained.

Using the set normalization coefficient A, the distance r for each node is converted (step 104),
Thereby, the display data is created (step 105).
As a result, it is possible to display a map of the range including the destination. A display example in this case is shown in FIG. × in the figure
The mark indicates the destination. If the normalization coefficient A can be changed by operating the operation unit 5, the display range can be arbitrarily changed. (Third Embodiment) In the first and second embodiments described above, the scale is increased as the distance from the current position (origin) of the vehicle is increased. In that case, the display density is set to be near the current position of the vehicle. If the display density of the map is the same, the distance change on the map display becomes smaller as the distance from the current position of the vehicle increases, so the map display becomes complicated.

In the present embodiment, the display density is reduced in a large distance range according to the distance from the current position of the vehicle. Hereinafter, a specific example of the process of changing the display density will be described. The map data stored in the storage device 4 is usually data in which display contents are thinned according to the scale of each map. For example, the map scale is 1
/ 10,000 maps use detailed information up to narrow streets, and maps with a scale of 1 / 80,000 use secondary roads. However, the coordinates such as line segments in each scale map maintain consistency in the map information. Similarly, the number of landmarks / various facility names is different between 1 / 10,000 maps and 1 / 80,000 maps.

Therefore, for example, the distance on the map display is 1/2
The range is set, and the above-mentioned coordinate conversion is performed based on the map data of the map of 1 / 10,000 in that range, and the coordinate conversion is performed based on the map data of 1 / 80,000 in the other range. The map is displayed at a display density based on a scale map. As another method, in the display data creation process of step 105, the road type shown in FIG. 2 is used, links according to the road type are selected according to the distance from the current position of the vehicle, and the selection is performed. Follow the steps to display the map. By selecting a road according to such a road type, for example, a range from the current position of the vehicle to a narrow street is displayed, and a range from 1 km to 10 km is displayed as a main road. Only the main local roads can be displayed for the range exceeding the limit. A display example in this case is shown in FIG.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicular navigation device showing an embodiment of the present invention.

FIG. 2 is a diagram showing a data structure of link information.

3 is a flowchart showing a calculation process of a control device 6 in FIG.

FIG. 4 is a diagram showing a display example when a grid-shaped map is subjected to coordinate conversion using a logarithmic function.

FIG. 5 is a diagram showing a display example in the first embodiment.

FIG. 6 is a flowchart showing a main part calculation process of a control device 6 in the second embodiment.

FIG. 7 is a diagram showing a display example in the second embodiment.

FIG. 8 is a diagram showing a display example in the third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... GPS receiver, 2 ... direction sensor, 3 ... wheel speed sensor, 4 ... memory | storage device 4, 5 ... operation part, 6 ... control device, 7 ...
Display device 7.

Claims (6)

[Claims] 1. A navigation device for a vehicle, comprising: a control means (6) for displaying a current position of a vehicle and a map on a display means (7), wherein the control means uses the current position as an origin and extends in the circumferential direction thereof. A vehicular navigation device, wherein a map whose scale is continuously increased as the distance from the current position increases is displayed on the display means. 2. The map is displayed by connecting positions defined by the coordinates of a plurality of map constituent points, and the control means (6) is arranged between the current position and the map constituent points. A means for converting coordinates of map constituent points so that the scale is continuously increased as the distance increases (1
03-105), The navigation device for vehicles of Claim 1 characterized by the above-mentioned. 3. The vehicle according to claim 2, wherein the means for converting the coordinates of the map constituent points includes means (104) for logarithmically converting the distance between the current position and the map constituent points. Navigation device. 4. The vehicular navigation device according to claim 1, wherein the control unit has a unit (108) for changing a change rate of the scale. 5. The means for changing the change rate of the scale is for changing the change rate of the scale according to the distance between the current position and the destination. Vehicle navigation system. 6. The control unit reduces the display density of the map in a display area in which a distance from the current position is a predetermined distance or more, according to any one of claims 1 to 5. Vehicle navigation system.