JPH04256992A - Map data updating method for on-vehicle navigation device - Google Patents

Abstract

PURPOSE:To shorten the time required to display a map area adjoining to a currently displayed map by reading map data on a place for which the traveling direction of a vehicle is predicted, by screen and developing and storing the data when the map data are updated. CONSTITUTION:When the current position of the vehicle traveling on a rod reaches a map updating line, the position of the intersection of the in-travel road and the boundary line VMB of map data on a video memory is reference to update 1st map data or find track data at every a constant distance on the in-travel road. A future travel route is estimated according to the track data and the position of the intersection of this estimated traveling route and the boundarty line VMB of the map data on the video memory is referenced to update the 1st data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for updating map data of an on-vehicle navigation system.

0002

2. Description of the Related Art FIG. 3 is a block diagram showing the schematic structure of an on-vehicle navigation system. In order to calculate the current position of the vehicle, data indicating the current position of the vehicle is input from the vehicle speed sensor 1 and the direction sensor 2 to the microprocessor 10 via the sensor input control section 3. microprocessor 10
is composed of a current position calculation processing section 11 and a road map display processing section 12, and various calculation programs stored in the main memory 4 are stored in a map file device 6 connected via a map file control section 5. The current position of the vehicle and the map information to which this vehicle belongs are read out and displayed on the display device 20 via the display control section 8.

The map data read from the map file device 6 is temporarily stored in a video memory 30, and the necessary portions are displayed on the display device 20. Display of map information is transmitted to the road map display processing section 12 via the key control section 7 by operating the key 9, and processing is executed.

This type of device displays a road map using the method shown in FIG. (1) Based on the current position calculated by the current position calculation processing unit 11, a map for nine screens centered on the display screen corresponding to the map including this current position is read from the map file device 6 consisting of a CD-ROM or the like. (Step 401) The image is developed into a bit image via the display control unit 8 having an extraction function, and stored in the video memory 30.

[0005] After the map data for nine screens has been developed and stored in the video memory 30 (step 402
), the address of the video memory is calculated so that the current position is located at a predetermined position (for example, the center) of the display screen, and this is set as the screen display start address in the display control unit 8, so that the current position is located at a predetermined position on the screen. A map located at the location is displayed (step 403).

As shown in FIG. 4, a1 to a4, a located around the display screen a5 corresponding to the map including the current position P.
6 to a9 are read out from the map file device 6 and stored in the video memory 30. Then, only the display screen a5 corresponding to the map including the current position P is displayed on the screen of the display device 20.

(2) The current position or road map is scrolled as the car travels, but the video memory 3
Since the map stored in 0 is only for 9 screens, it is necessary to update the map. FIG. 5 is a diagram for explaining the map updating method, and explains the procedure of map data reading, expansion, and storage processing at the time of updating.

Generally, a map update line MRL is provided on the video memory, and the map is updated when the current position reaches the update line MRL. In addition, the display screen scrolls as the vehicle moves, but it is possible to either move the current location of the vehicle or move the road map while keeping the current location of the vehicle in the center of the screen. It has been adopted (step 501).

In this manner, when the current position of the vehicle reaches the map update line MRL previously provided on the video memory (step 502), map data for nine new screens or three or five adjacent screens is updated. data (step 503). The newly read data in this way
The data and previous data are obtained and expanded and stored in the video memory 30 (step 504). When displaying, only the screen to which the new current position at the time of display belongs is displayed (step 505).

As shown in FIG. 5, nine screens a11 to a3 are displayed centering on the current position a22 to which the original current position P belongs.
3 was stored in the video memory 30 before the update, but
When the current position moves to P', new screen data a' is created with screen a'33 to which P' belongs as the new central screen.
22 to a'44 are read and updated with the previous data.

[0011] In the case shown in Fig. 5, nine new screens are read out with the current position P' at the time of update as the center position, but in the case of a method in which only 3 or 5 adjacent screens are read out. The screen a'33 becomes the lower right screen data a33 before updating. Conventionally, map data has been updated using one of the following two methods.

[0012] ■ 9 centered on the map including the current location
A method of reading a screen's worth of data from a map file, expanding and storing it in video memory. (2) A method of reading out from a map file the data of the 3rd to 5th map screen that is not stored in the video memory when the map containing the current position is centered, and expanding and storing it in the video memory.

[0013]

[Problems to be Solved by the Invention] However, in the conventional map data updating method described above, map data for at least three screens must be updated.
data from the map file, expand it to video memory, and
Since adjacent maps are displayed after accumulation, there is a problem in that the map update time becomes long. Therefore, if a car is moving at high speed while displaying a large-scale, detailed map, even if the current location has reached a new map area, the map data for that part will still be displayed on the video. A situation occurs in which the latest status cannot be displayed because the information is not stored in memory.

The present invention has been made to solve the above-mentioned problems, and when updating map data, the map data of the place where the vehicle is predicted to proceed is read screen by screen, expanded and stored. , map data for in-vehicle navigation devices that can speed up the display time of adjacent map areas of already displayed maps.
The purpose is to provide a method for updating data.

[0015]

[Means for Solving the Problems] The present invention provides an in-vehicle navigation game.
In the map data update method of the application device, when the current position of the car reaches the map update line on the road in progress, the intersection position of the road in progress and the boundary line of the map data on the video memory is referred to. Then, the first map data is updated, or trajectory data is obtained every time a certain distance is traveled on the current road, and a future route is assumed based on this trajectory data. The first data is updated by referring to the intersection point between this assumed route and the boundary line of the map data on the video memory.

[0016]

[Operation] In the present invention, when the vehicle reaches the map update line, a prediction process is performed to estimate the direction of travel of the vehicle, and according to the prediction result, the map data of the place where the vehicle is predicted to travel is first Read and update. Then, the map data of the screen closest to the screen to which the first map data belongs is updated to the second map data. Therefore, even if the car is moving at high speed, updated map data can be displayed on the screen at high speed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a prediction process for estimating the direction of travel of a vehicle is used when updating a map. There are several methods of prediction processing as shown below.

■ Map update line MRL on the driving road
It is assumed that the vehicle will continue on the road beyond 200 meters, and the direction of travel is estimated from the map data stored in the main memory 4. (2) A certain number of past trajectories of traveling roads are stored in the main memory 4, and when the map update line MRL is reached, the direction of travel is estimated based on the overall angle. ■ Estimate the direction of travel by combining the above ■ and ■.

First, method (2) will be explained. FIG. 1 is an explanatory diagram when estimating the traveling direction using the method (2). The intersection positions of each road and the boundary line VMB of the map data on the video memory are stored in the main memory 4 in advance at initial values or at the time of each map update. In FIG. 1, P(R10), P(R20), and P(R21) are the intersection positions.

[0020] Here, the current position is from P to map update line M.
When the position P' on RL is reached, the first screen to be updated is determined based on this position with reference to the intersection position P (R10) of the road R1 in progress.

Next, method (2) will be explained. FIG. 2 is a diagram for explaining the method (■). For example, every time a certain distance is traveled, trajectory data is
), . . . are stored in the main memory 4. This trajectory day
Assuming a future route using the latest N data,
The intersection point P (R10) between the assumed progression route and the video memory boundary line VMB is determined, and the first screen to be updated first is determined based on this position. Note that in any of the cases described above, the first screen is a43 in the examples of FIGS. 1 and 2.

[0022] Next, the determined P on the first screen is
The second screen and subsequent screens are determined by the position of (R10). In this case, the most common method of determining is the expected progression intersection (Figs. 1 and 2) on the video memory boundary line VMB (R1
Perform the following depending on the position of 0).

■ The intersection position is the video memory boundary line VM
In this case, if the intersection point is on the right half of the first screen video memory boundary line VMB, the right adjacent screen of the first screen is set as the second screen. Note that the cases shown in FIGS. 1 and 2 correspond to this example. If the screen is on the left half, the screen adjacent to the left side of the first screen is set as the second screen.

■ The intersection position is the video memory boundary line VM
If it is on the vertical line of B, if the intersection point is in the upper half of the first screen video memory boundary line VMB, the upper adjacent screen of the first screen is the second screen, and if it is in the lower half, it is the lower part of the first screen. The adjacent screen is set as the second screen.

[0025] From the third screen onward, the intersection point P' of the current road or the assumed route and the map update line MRL is displayed.
The adjacent screens of the first and second screens are determined so that there are nine screens in all, centered on the screen where is located.

[0026]

[Effects of the Invention] As explained above, the present invention
When updating data, prioritize each screen to be processed.
First, the first screen is read and expanded point accumulation processing is performed to make it displayable, and then the second and subsequent screens are similarly processed one by one, thereby reducing the time until the adjacent map is displayed. Therefore, it is possible to solve the problem that when updating a map, it takes a long time to display an adjacent map and the map is not displayed.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a second embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of an in-vehicle navigation device used in the present invention.

FIG. 4 is a diagram for explaining a conventional map data reading and display method.

FIG. 5 is a diagram for explaining a conventional map data updating method.

[Explanation of symbols]

4 Main memory 5 Map file control section 6
Map file device 8 Display control section 11 Current position calculation processing section 12 Road map display processing section 20 Display device 30 Video memory MRL Map update line VMB Video memory boundary line

Claims (4)

[Claims] Claim 1: Map data for nine screens, centered on a map containing the current position of the car, is read out from a map file device in which road map data is stored, and stored in a video memory. In a map data update method for an in-vehicle navigation device that updates map data for the nine screens when the current position of the vehicle reaches a map update line provided on the video memory, When the current position of the vehicle reaches the map update line, the first map data is updated by referring to the intersection position of the road in progress and the boundary line of the map data on the video memory. 1. A method for updating map data of an in-vehicle navigation device. 2. In the map data updating method according to claim 1, when the intersection position is on the right half of the boundary line in the horizontal direction, the display screen belonging to the first map data is Map data corresponding to the adjacent screen on the right side, map data corresponding to the adjacent screen on the left side if it is on the left half,
In addition, if the intersection position is in the upper half of the vertical boundary line, map data corresponding to the upper adjacent screen of the display screen belonging to the first map data is displayed, and if it is in the lower half, map data corresponding to the upper adjacent screen of the display screen belonging to the first map data is displayed. 1. A map data updating method for an in-vehicle navigation device, characterized in that map data corresponding to a lower adjacent screen is updated as second map data. [Claim 3] Nine screens of map data centered around a map including the current position of the car are read out from a map file device in which road map data is stored, and stored in a video memory. In the map data update method of the in-vehicle navigation device, which updates the data for the nine screens when the current position of the car reaches the map update line provided on the video memory, Trajectory data is obtained for each distance traveled, a future route is assumed based on this trajectory data, and the relationship between this assumed route and the boundary line of the map data on the video memory is calculated. 1. A map data updating method for an on-vehicle navigation device, characterized in that first map data is updated by referring to an intersection position. 4. The data updating method according to claim 3, when the intersection position is on the right half of the boundary line in the horizontal direction, the data adjacent to the right side of the display screen belonging to the first data is map data corresponding to the screen, if it is on the left half, map data corresponding to the left adjacent screen, and if the intersection position is on the upper half of the vertical boundary line, the map data corresponding to the left side adjacent screen; The map data corresponding to the left side adjacent screen of the display screen belonging to the first map data is stored as the second map data, and the map data corresponding to the lower adjacent screen when it is in the lower half is stored as the second map data. - A method for updating map data of an in-vehicle navigation device, characterized in that map data is updated as a map data.