JPH0740172Y2 - Car navigation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an on-vehicle navigation device, and particularly to a vehicle navigation system even if there is a difference between a road of map information stored in a storage medium and an actual road. The present invention relates to an on-vehicle navigation device that can match the current position on the correct road.

[Prior art]

Conventionally, a so-called map matching method has been used in navigation systems. That is, the map information provided from the storage medium is displayed on the display device, and the map information and the data provided by the position detection sensor such as the direction sensor and the distance sensor are comprehensively considered on the road of this map information. The current position of the vehicle calculated by the above is matched.

For example, as shown in FIG. 6, point a to point b of the map information
If you drive on the road and turn at point b toward point c,
The vehicle travels on the roads at points a and b at the road angle θab, and the current position is aligned and synthesized on the road. At point b, the loci of a, a, and u are drawn from the error of the distance sensor. There may be cases where the vehicle makes a turn. In this case, the road angle derived from the point b, that is, the nearest node (inflection point) b is compared with the angle obtained from the azimuth sensor, and the road having the closest angle is determined to be the road to be traveled thereafter. The current position of point b
To the road between point and point c.

[Problems to be solved by the device]

By the way, it is practically impossible to record even small roads such as alleys as a storage medium used in the navigation system. It is unavoidable that there will be a discrepancy in the road conditions between the two. Further, there may be an error in the used distance sensor, vehicle speed sensor, or the like. Therefore, if the current position of the vehicle is matched with the road of the map information, the current position may be combined with a road different from the actual road, and there is a problem that the error gradually increases as the vehicle travels.

For example, as shown in FIG. 7, the current position of the vehicle is the road e.
-When the locus Δ is drawn on -b, there is no road that can go straight on at node b, so there is a constant radius centered on node b.
A road having a node in SR1 is searched, the road ah is determined to be a road to be driven thereafter, and map matching is performed. However, the locus × is drawn at another position in the data of only the sensor, and SR2 within a certain radius centered on the locus ×
There is a road c-g with the node c at. Even if there is an error from the true position, the current position obtained from the data of only this sensor is not extremely large. Therefore, in such a case, it is difficult to restore the road to the true position by distant from the raw information and not using the road a-h instead of the road c-g.

The present invention was devised in order to eliminate the above-mentioned problems in view of the above-mentioned circumstances, and there is a discrepancy between the road condition of the map information stored in the storage medium and the actual road condition, a distance sensor, etc. It is an object of the present invention to provide an on-vehicle navigation device that prevents a matching error due to an error.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a position detecting sensor for detecting the current position of a traveling vehicle, a storage medium for storing road map information, and a current position of the vehicle based only on data from the position detecting sensor. And a calculation means for calculating the current position of the vehicle in consideration of the data from the position detection sensor and the data from the storage medium, and normally is calculated by the data from the position detection sensor and the data from the storage medium. Alignment means for aligning the current position of the vehicle on the road of the map information, display means for displaying the alignment result by the alignment means, and current vehicle calculated by the data from the position detection sensor and the data from the storage medium. When the position passes a predetermined position on the road of the above map information, the vehicle calculated based on the data from the position detection sensor and the data from the storage medium. It comprises a correction means for searching for a road within a certain range centered on the midpoint of the current position of the vehicle calculated only from the current position and data from the position detection sensor, and for matching as a road to be subsequently run. It was

[Action]

According to the configuration of the present invention, as the vehicle travels, the current position of the vehicle is calculated in consideration of the information provided from the position detection sensor and the information from the storage medium, and only the information from the position detection sensor is calculated. Although the current position of the vehicle is calculated based on this, the calculation result based on the information provided by the position detection sensor and the information from the storage medium is always displayed in alignment with the road in the map information of the storage medium. When the current position of the vehicle calculated from the information provided from the sensor and the information from the storage medium passes a predetermined position of the map information, the vehicle calculated from the data from the position detection sensor and the data from the storage medium A road within a certain range centered on the midpoint of the current position of the vehicle calculated only from the current position and the data from the position detection sensor is searched and Align the current position of the vehicle calculated by the information from the information and the storage medium provided from the position detection sensor as the road running in.

〔Example〕

 The present invention will be described based on an embodiment shown in the drawings.

FIG. 1 is a circuit configuration diagram, FIGS. 2 and 3 are operation explanatory diagrams of map matching, and FIGS. 4 and 5 are flowcharts showing control operations by the central processing unit shown in FIG.

In the on-vehicle navigation device 1 shown in FIG. 1, the central processing unit 4 calculates the current position of the vehicle based on the data provided from the azimuth sensor 2 and the mileage sensor 3, and the display device 5
The current position is synthesized and displayed on the road map displayed in. The map information provided to the display device 5 is CD-RO
It is stored in the external storage device 6 such as M. The road map data stored in the external storage device 6 is subdivided by assigning a number to each node (node) such as an intersection or a corner of the road, and a number to each road (link). The data stored in the external storage device 6 is read by the media controller 7 and temporarily stored in the buffer memory 8 via the central processing unit 4. The buffer memory 8 sequentially sends the necessary data to the image memory 9 via the central processing unit 4. The data stored in the image memory 9 is converted into an image by the display control device 10 and displayed on the display device 5. The data stored in the image memory 9 is updated as the vehicle travels. Reference numeral 11 is a keyboard for inputting and outputting various operations.

Next, the control operation by the central processing unit 4 will be described with reference to FIGS.
A description will be given based on the flowchart shown in the figure.

The flow chart of FIG. 4 shows the operation when there is no road in the direction in which the node b of the T-shaped road hits the T-shaped road as shown in FIG. First, in step 101, of roads b-a, b-c, and b-e derived from node b, a road whose angle matches the traveling direction of the vehicle, that is, the direction which goes straight through node b is selected. To do. As a result of the selection, it is determined in step 102 whether there is a matching road.
If there is a matching road as a result of the determination, the process proceeds to step 107, the current position of the vehicle is corrected to match the matching road, for example, roads bc, and then the process returns to the start. On the other hand, if there is no matching road in step 102 (if there is no road in the direction of going straight like node b in FIG. 2), step 10
Move to 3. In step 103, the midpoint C between the current position of the vehicle calculated from the data from the position detection sensor and the data from the storage medium and the current position of the vehicle calculated only from the data from the position detection sensor is calculated. . When the midpoint C is obtained, the midpoint C is calculated in step 104.
A road whose angle coincides with a radius SR3 with respect to is searched, and the result of the search is determined in step 105. As a result of the determination, when there is no matching road, the process proceeds to step 106,
The matching operation is canceled and the process returns to the start. When there is a matching road, for example, when the road c-g is a matching road in FIG. 2, the current position Δ of the vehicle is corrected on the road c-g to match it. After that, go back to the start.

Further, the flow chart of FIG. 5 shows the control operation when the vehicle bends at a point a where there is no node as shown in FIG. First, in step 201, it is determined whether or not the front node c has a road whose angle matches the traveling direction of the vehicle that has bent at a point a where there is no node. As a result of the determination, when there is a road whose angle matches, the process proceeds to step 207, the current position of the vehicle is corrected to match the matched road, for example, the road c-e, and then the process returns to the start. On the other hand, when there is no road whose angle matches, it proceeds to step 202 and it is determined whether there is a road whose angle matches the rear node a. As a result of the determination, when there is a road whose angle matches, the process proceeds to step 207 and the same operation as above is performed.
If there is no matched road, the process proceeds to step 203. In step 203, the midpoint C between the current position of the vehicle calculated from the data from the position detection sensor and the data from the storage medium and the current position of the vehicle calculated only from the data from the position detection sensor is calculated. . When the midpoint C is obtained, a road whose angle coincides with the center point C within the radius SR3 is searched in step 204, and the result of the search is determined in step 205. As a result of the determination, when there is no matching road, the process proceeds to step 206, the matching operation is canceled and the process returns to the start, and when there is a matching road, for example, the third road.
In the figure, when the road d-c is a coincident road, the current position Δ of the vehicle is corrected on the road d-c so as to be aligned, and then the process returns to the start.

[Effect of device]

As is apparent from the above description, according to the present invention, the current position of the vehicle calculated from only the data from the position detection sensor and the current position of the vehicle calculated from the data from the position detection sensor and the data from the storage medium. Both of the above are managed, and matching roads are searched and matched within a certain range centered on the midpoint of both, so that the current position of the vehicle can be detected with higher accuracy.

[Brief description of drawings]

FIG. 1 shows an embodiment of a vehicle-mounted navigation device according to the present invention. FIG. 1 is a circuit configuration diagram, FIGS. 2 and 3 are map matching operation explanatory diagrams, and FIGS. 4 and 5 are FIG. A flowchart showing a control operation by the central processing unit shown in FIG.
6 and 7 are explanatory views of map matching. (Explanation of reference numerals of drawings showing main parts) 1 ... In-vehicle navigation device, 2 ... Direction sensor 3 ... Distance sensor, 4 ... Central processing unit 5 ... Display device, 6 ... External storage device 7 ... … Media controller 8 …… Buffer memory, 9 …… Image memory 10 …… Display controller, 11 …… Keyboard

Claims (1)

[Scope of utility model registration request] 1. A position detection sensor for detecting the current position of a traveling vehicle, a storage medium for storing map information of roads, and a current position of the vehicle calculated based only on data from the position detection sensor. The calculating means for calculating the current position of the vehicle in consideration of the data from the detection sensor and the data from the storage medium, and the current position of the vehicle which is always calculated by the data from the position detection sensor and the data from the storage medium Matching means to match the map information on the road,
Display means for displaying the matching result by the matching means, and a position detection sensor when the current position of the vehicle calculated by the data from the position detection sensor and the data from the storage medium passes a predetermined position on the road of the map information. The current position of the vehicle calculated from the data from the storage medium and the data from the storage medium and the current position of the vehicle calculated from the data from the position detection sensor are searched for roads within a certain range centered on the midpoint. An in-vehicle navigation device comprising a correction means for alignment as a road on which the vehicle travels thereafter.