JP2886991B2 - Vehicle position correction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting a vehicle position, and more particularly to a method for correcting a vehicle position by a map mapping process.

[0002]

2. Description of the Related Art Navigation systems for automobiles are:
It has a large-capacity storage device such as a CD-ROM for storing a large amount of map data, a display device, a position measuring device for measuring the current position of the vehicle, etc., and reads map data corresponding to the current position of the vehicle from the CD-ROM. A map is drawn on a display screen based on the map data, and a vehicle position mark is moved on the map in accordance with the movement of the vehicle, or the mark is fixedly displayed at a fixed position on the display screen and the vehicle is displayed. The map is scrolled in accordance with the movement of.

The map stored in the CD-ROM is divided into regions of appropriate longitude and latitude widths according to the scale level, and roads and the like are represented by vertices (nodes) expressed in latitude and longitude. Are drawn by connecting each node in order with a straight line. A portion connecting two or more nodes is called a road link.

[0004] The car navigation system has a function of displaying the trajectory of the own car together with a map. In such a trajectory display, a vehicle position is obtained discretely from the azimuth of the vehicle and the number of rotations of the tires, and a set (point sequence) of these discrete vehicle positions is set as a traveling trajectory and drawn on a map. However, when the detection errors of the direction sensor and the speed sensor are accumulated, the vehicle position mark deviates from the correct road. For this reason, the shape of the traveling locus is stored,
A method called map matching has been proposed in which the traveling locus is compared with the road shape of the map data to correct the vehicle position mark on the correct road and correct the traveling direction in the correct direction.

FIG. 5 is an explanatory diagram of map matching.
When the vehicle moves on the road RD in the northeast direction and reaches the point Pc via the point Px, the vehicle position mark CM is displayed on the point Pc ', and the traveling locus RTD is indicated by a dotted line. It is assumed that it is indicated by.
In map matching, every time the vehicle travels a predetermined distance,
(1) Using the map data, search for a road path RD having the same shape as the shape of the traveling locus RTD. (2) Pay attention to a reference point, for example, the latest node Px.
Point Pc on road path RD such that c '= PxPc
(3) After that, the vehicle position mark CM is moved from the point Pc 'to the point Pc.

[0006]

According to this map matching process, the vehicle position (running locus) and running direction can be corrected to the correct position and direction even if there is an error in the sensor. However, when there are many road paths having the same shape as the traveling locus (see RD1 and RD2 in FIG. 6), it is not possible to determine which road path the vehicle position may be corrected for, and the vehicle may not be located on the wrong road. There is a problem of displaying the position and the running locus.

In particular, an expressway and an ordinary road are often parallel to each other, and it cannot be determined in map matching whether the vehicle position should be corrected on the expressway or on the general road. From the above, the object of the present invention is:
It is an object of the present invention to provide a vehicle position correcting method capable of automatically correcting a vehicle position mark on a correct road path even when a plurality of road paths having the same shape as a traveling locus exist.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a means for obtaining a road path having the same shape as the shape of a traveling locus. This is achieved by means for obtaining the speed limit of the road path from the road information included in the map data and means for correcting the vehicle position on the road path having the smallest difference between the current traveling speed and the speed limit.

[0009]

When the vehicle position mark deviates from the road, a road path having the same shape as the shape of the vehicle traveling locus is obtained. If there is only one road path having the same shape, the vehicle position is determined on the road path. When the position is corrected and there are two or more road paths having the same shape as the shape of the vehicle traveling locus, the speed limit of each road path is obtained from the road information included in the map data, and the difference between the current running speed and the speed limit is calculated. Correct the vehicle position to a position on a small road path.

[0010]

EXAMPLES overall configuration diagram 1 is a block diagram of an automotive navigation system according to the present invention. In the figure, 1 is a CD-RO serving as map data storage means
Reference numerals M and 2 denote operation panels provided with various keys such as left, right, up, and down scroll keys for scrolling the map with respect to the vehicle position mark, map search, and enlargement / reduction. I have. Reference numeral 3 denotes an azimuth sensor for detecting an absolute azimuth, reference numeral 4 denotes a movement amount sensor, such as a speed sensor for detecting a traveling distance, and a transmission sensor for detecting forward / backward travel. 5 is C for position calculation
The PU calculates the current position (longitude, latitude) of the vehicle based on the respective values input from the direction sensor 3 and the movement amount sensor 4.

Reference numeral 6 denotes a data processing device having a system controller (CPU) 7, a map data buffer memory 8, and the like. The system controller 7 has a navigation processing section 7a and a map matching processing section 7b. (1) Map data corresponding to the current position of the vehicle is stored in the CD-ROM 1
To the buffer memory 8 and input the map data to a display device to draw a map. (2) Change the map read address (window address) according to the driving of the car and scroll the map. 3) The current position data of the car is stored discretely as a travel locus (navigation processing), and (4) a map matching process is performed to correct the car position. (5) A road having the same shape as the shape of the travel locus. A vehicle position correction process or the like when two or more paths exist is performed. A display device 10 includes a CRT controller 11, a video RAM (VRAM) 12, a readout control unit 13, a cathode ray tube (CRT) 14, and the like, and displays a desired map and marks on the CRT. .

[0012]Map data  The map data stored in the CD-ROM 1 is (1)
From road link data, intersection data, node data, etc.
And (2) objects on the map
Background layer and (3) names of municipalities, national roads, etc.
It is composed of a character layer for indicating.

The road layer has a data structure shown in FIG. Among them, the road link data RLDT gives attribute information of the corresponding road link, and all the links on the link are provided.
Number of nodes, each node that constitutes a link, road name, speed limit,
It is composed of data such as the type of road (national road, expressway, and others). The intersection data CRDT is, for each intersection on the map, a set of nodes closest to the intersection on the link connected to the intersection (referred to as an intersection configuration node), and the node data NDDT is on the map. This is a list of all the nodes, location information (longitude, latitude) for each node, an intersection identification flag indicating whether or not the node is an intersection, if it is an intersection, it indicates intersection data, and it must be an intersection. If the
And a pointer indicating the link to which the node belongs.
The speed limit included in the road link data RLDT is used in a map matching process described later.

FIG. 3 is a flowchart of the vehicle position correcting process of the present invention, and FIG. 4 is an explanatory diagram of the present invention. The following description will be made with reference to these drawings. The system controller 7 reads predetermined map data from the CD-ROM 1 into the buffer memory 8 in accordance with the running of the automobile, inputs the map data to the display device 10 to draw a map, and also outputs a map read address (window-address). ) To scroll the map (navigation processing, step 10).
1). Further, the system controller 7 discretely stores the latest several vehicle positions (coordinates and latitudes) in a built-in memory to generate travel locus data, and inputs the travel locus data to the display device 10 to display the travel locus RTD. (Step 102).

Each time the vehicle travels a predetermined distance, the system controller 7 compares the shape of the travel locus RTD with the road shape of the map data to obtain a road path having the same shape as the travel locus (map matching, step 103). Thereafter, it is checked whether there are two or more road paths having the same shape as the traveling locus RTD (step 104). If there is only one road path having the same shape, the vehicle position mark is set at a position on the road path. C
M is corrected and displayed on the CRT 14 (steps 105, 1
06), and thereafter, the processing of step 101 and thereafter is repeated.
On the other hand, as shown in FIG. 4A, when there are two or more road paths having the same shape as the traveling locus RTD (the road path HWY,
GWY), the speed limits V ₁ and V ₂ of each path are read from the road information included in the map data (step 107).

Next, the speed included in the movement amount sensor 4 is
The current running speed Va from the output from the speed sensor
(Step 108). Once the speed limits V ₁ , V of each path and the current travel speed Va are obtained, the differences | Va−V ₁ |, | Va−V ₂ | between the current travel speed and each speed limit are calculated, and the differences are calculated. The minimum road path is determined (step 109), and the vehicle position mark is corrected to a position on the road path with a small difference in speed limit and displayed (steps 105 and 106).

For example, if the road path HWY is a highway and the speed limit is 100 km / h, the road path GWY is a general road and the speed limit is 50 km / h and the current traveling speed is 80 km / h or more, the vehicle is traveling on the highway. And the vehicle position mark CM is corrected on the road path HWY as shown in FIG. On the other hand, if the current traveling speed is 50 km / h,
Assuming that the vehicle is traveling on a general road, vehicle position mark CM
On the road path GWY.

[0018]

As described above, according to the present invention, when the vehicle position mark deviates from the road, a road path having the same shape as the shape of the vehicle traveling locus is obtained. When the position is corrected to a position on the road path, and there are two or more road paths having the same shape as the shape of the vehicle traveling locus, the speed limit of each road path is obtained from the road information included in the map data, and the vehicle position is determined. Is corrected to the position on the road path where the difference between the current traveling speed and the speed limit is small, so that even if there are multiple road paths having the same shape as the traveling locus, the The vehicle position mark can be corrected, which is particularly effective when an expressway and a general road having a large difference in speed limit are parallel to each other.

[Brief description of the drawings]

FIG. 1 is a block diagram of an automobile navigation system according to the present invention.

FIG. 2 is a configuration diagram of map data.

FIG. 3 is a flowchart of the process of the present invention.

FIG. 4 is an explanatory diagram of a map matching process of the present invention.

FIG. 5 is an explanatory diagram of a general map matching process.

FIG. 6 is an explanatory view of a defect of the conventional map matching processing.

[Explanation of symbols]

 1. CD-ROM 2. Operation panel 4. Moving amount sensor 6. Data processing device 7. System controller 7a Navigation processing unit 7b Map matching processing unit

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G09B 29/10 G01C 21/00 G08G 1/0969

Claims (1)

(57) [Claims] 1. A map is displayed on the basis of map data corresponding to a current position of a vehicle, and a mark indicating the current position of the vehicle is moved and displayed relative to the map in accordance with the movement of the vehicle. In the vehicle position correction method of the automobile navigation, when the vehicle position mark deviates from the road, a road path having the same shape as the shape of the vehicle traveling locus is obtained. If there is only one road path having the same shape, the vehicle position is determined. Is corrected to a position on the road path, and when there are two or more road paths having the same shape as the shape of the vehicle traveling locus, the speed limit of each road path is obtained from the road information included in the map data, and the current traveling speed is calculated. And correcting the vehicle position to a position on a road path where the difference between the vehicle speed limit and the speed limit is small.