JP2690384B2 - Mobile navigation device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation apparatus for a mobile object suitable for use in a navigation system that displays the current position of a car on a map.

[Conventional technology]

FIG. 6 shows a method of displaying the current position of a car on a map, which is used in the conventional car navigation system disclosed in Japanese Patent Laid-Open No. 63-96690, for example. The starting points, b, c, and d points indicate the respective traveling points when traveling in the arrow direction on the road from the point a. A, B, C... I indicate districts obtained by further dividing the map in the predetermined area.

 Next, the operation will be described.

In FIG. 6, the car is a starting point a in district E.
When the user is in, a map of this area E and the eight areas A to D and FI adjacent to the area E is displayed together with the point a. Next, when the car travels, the display point of the current position on the road moves accordingly, but as long as the car is in the area E, the areas A to I centering on the area E
The display of does not change. The display changes when a car enters the adjacent area F, and eight adjacent areas centering on the area F are displayed. That is, instead of the areas A, D, and G that have been displayed until then, three adjacent areas (not shown) on the right side of the area F are displayed. In this way, the area where the automobile is always present and the eight adjacent areas centering on this area are displayed.

In the navigation apparatus of the mobile object for performing the above display, a large-capacity storage device such as a CD-ROM storing map data of a plurality of districts is provided. Then, in a memory such as a work RAM for performing processing such as position calculation and map drawing calculation according to the position detection of the car, the map data of the necessary area is read from the storage device, and the read map data is read. The arithmetic unit is configured to perform a predetermined process by using the arithmetic unit. When the map data is read from the storage device, first, the map data of the area where the automobile is located is read, and then the map data of a plurality of areas adjacent to this is read in a predetermined order and stored in the memory. It is designed to be transferred. Therefore, the map drawing process is performed in the order of transfer. In the case of FIG. 6, first, after the map data of the area E is read into the memory, the map data of the adjacent areas are displayed in a predetermined order, for example, A, B, C, D, F, G, H, I
Are read into the memory in this order, and position calculation and drawing processing are performed in this order.

[Problems to be solved by the invention]

Since the conventional mobile navigation device is configured as described above, the order of reading the map data of a plurality of adjacent areas into the memory is fixed, which causes the following problems. For example, in FIG. 2, it is assumed that a moving body such as a car is located at a point a in the area F. It is assumed that point a is the closest to district J. At this time, if it is assumed that the map data of the area adjacent to the area F is read into the memory in the order of A, B, C ..., The reading is started from the area A farthest from the point a. If the map data is composed of vectors, character codes, etc., it takes time to read the data, and it takes a considerable time to finish reading the last district K. Since the arithmetic unit uses the map data read in the memory to calculate the position detection, drawing, etc. of the mobile unit, the mobile unit may not be ready before the necessary map data are available.
In the case of moving to a neighboring area near from, the display will change before the map of the point a that the user wants to know most is not sufficiently drawn.

The present invention has been made to solve the above problems, and an object thereof is to obtain a navigation device for a mobile body that can speed up map drawing processing regarding the current position of the mobile body.

[Means for solving the problem]

The mobile navigation device according to the present invention obtains the distances from the current position for each of a plurality of districts adjacent to the district including the current position, and reads the district data into the memory in order from the district with the shortest distance. It is the one.

[Action]

In the mobile navigation device according to the present invention, the map data regarding the current position is obtained at the beginning of the process, so that the map drawing process regarding the current position is reliably performed.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a position sensor including a direction sensor and a distance sensor provided on a moving body (not shown) such as an automobile vehicle, and 2 denotes a moving direction and a moving distance obtained from the position sensor 1, which will be described later. A position detection device for determining the position of the moving body by collating with map data, 3 is a map data storage device composed of a CD-ROM or the like in which map data of a plurality of districts is stored, and 4 is a device from the position detection device 2. A map reading device 5 for reading out map data of a required area from the data storage device 3 on the basis of a position signal and reading the map data into a memory 5 described later is a RAM into which the map data reading device 4 reads the necessary map data. And the like, 6 is a drawing device for drawing a map based on the map data from the memory 5 and the orientation and position from the position detecting device 2, and 7 is a switch operated by the user. Setting the position of the mobile by sending various commands to a fine drawing apparatus 6, performs scaling, etc. of the map.

 Next, the operation will be described.

First, the present invention will be described in principle with reference to FIG.
In FIG. 2, it is assumed that the moving body is now at point a in district F. Therefore, at this time, eight adjacent districts centering on the district F are districts A, B, C, E, F, G, I, J, and K. Further, as shown in the figure, the point a is closest to the district J at the shortest distance, and thereafter, the regions G, K, E, I, B, C, and A are in that order.
In the present invention, the map data is read into the memory 5 in the above order. Therefore, the map data of the districts J, K, and G near the point a are quickly collected, so that the map about the point a can be drawn quickly and the map can be displayed.

Next, the operation based on the above principle will be described with reference to FIG. 2 as an example together with the flowchart of FIG.

First, in step ST1, the map reading device 4 reads the position signal obtained from the position detecting device 2. Steps
In ST2, the area F including the point a of the moving body is detected, and this is registered as No. 1 in the request list as the central area. Next, in step ST3, adjacent districts A, B, C, E, F, G, I, J, K of the central district F
After listing, the shortest distance from the point a of each adjacent area is calculated in step ST4. And step ST5
, J, G, K, E, I, B, C,
Sorted with A, and in step ST6, request list No. 2 ~
Register in 9. At step ST7, it is checked whether or not the map data of each district is already stored in the memory 5. For those that are not stored, secure the storage area by erasing unnecessary data in step ST8, etc., then read the necessary map data in step ST9, No. 2 ~ No. 9 of the above request list Follow the order. Steps ST7, ST8, ST9 are repeated until it is detected in step ST10 that the reading of the map data of all districts is completed. When the reading of the map data of all districts is completed, it returns to the main processing of the system.

When the moving body moves from point a to point b in FIG. 2, the map data for districts A, E and I stored in memory 5 is deleted and the map data for districts D, H and L are replaced. Will be read.

In the above-described embodiment, the shortest distance from the central area is calculated for each adjacent area, and the request list No. 2 to N are calculated.
Although the rearrangement is made to o.9, this rearrangement may be performed as follows by using a preset table.

As shown in FIG. 4, the central area is divided into 1 to 16 subareas, and the eight adjacent areas are set as to create the table of FIG. Now, for example, assuming that the moving body is in the second subdistrict in the central district, the reading order of the adjacent districts in this case is as follows from the table in FIG. District closest to the sub-district, third closest district, and so on ...
Are read in this order.

In the above embodiment, the position sensor 1 is used to detect the position of the moving body, but a known method using a GPS satellite or the like may be used.

The vertical and horizontal coordinates of the district may be the scale of the actual distance or the longitude and latitude.

〔The invention's effect〕

As described above, according to the present invention, for each of a plurality of districts adjacent to the district including the position of the moving body, the distance from the current position is obtained, and the district data is read into the memory in order from the district with the shortest distance. Since it was done, make sure to draw the map of the current position of the moving body,
Since the map can be surely displayed, it is possible to display the current position so that the current position can be easily grasped, and it is possible to obtain the effect at low cost by simply changing the software.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a navigation device for a mobile body according to an embodiment of the present invention, FIG. 2 is a block diagram of an area for explaining the principle of the device, and FIG. 3 shows an operation procedure of the device. A flow chart, FIG. 4 is a block diagram of a district showing another embodiment of the same device, FIG. 5 is a block diagram of a table used in another embodiment, and FIG. 6 is a view for explaining a conventional automobile navigation system. It is a block diagram of the district. 2 is a position detection device, 3 is a map data storage device, 4 is a map reading device, 5 is a memory, and 6 is a drawing device. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of the front page (56) Reference JP 63-96690 (JP, A) JP 62-111399 (JP, A) JP 61-212723 (JP, A) JP 61-250671 (JP , A) JP-A-3-27082 (JP, A) JP-A-2-240680 (JP, A)

Claims (1)

(57) [Claims] 1. A map data storage device for storing map data divided into a plurality of areas, a memory to which map data read from the map data storage device is transferred, and a position signal indicating the position of a moving body. Based on this, the area including the position of the moving body and a plurality of areas adjacent to this area are detected, and the shortest distance from the position of the moving body is calculated for each of the plurality of adjacent areas. The map data of the area is sequentially read from the map data storage device and transferred to the memory, and the moving direction and the moving distance of the mobile unit are compared with the map data read in the memory to move the map data. A position detecting device that determines the position of the body and outputs the position signal, and the moving body based on the position signal and the moving direction and the map data read in the memory. Position and the moving body navigation device and a drawing device for drawing a map.