JP3403291B2 - Car navigation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted navigation device, and more specifically, correction of a displayed vehicle position when there is a difference between a detected vehicle position and a position based on road information on a map, so-called. The present invention relates to a vehicle-mounted navigation device that performs map matching.

[0002]

2. Description of the Related Art In conventional vehicle-mounted navigation devices,
The position and traveling direction of the own vehicle are detected, the map information around the own vehicle position is read from the CD-ROM, and the own vehicle position mark is displayed on the road map created from the map data. Usually, in the map data stored in the CD-ROM, roads are points (nodes) expressed based on latitude and longitude.
It is remembered as a connection.

On the other hand, there is often a difference between the position based on the own vehicle position information obtained by the own vehicle position detecting means and the position based on the road position information of the map data, and the displayed own vehicle position is displayed on the road. Needs to be fixed. Therefore, the display own vehicle position is corrected so that the own vehicle is located on the road position on the map from the own vehicle position obtained from the own vehicle position information, and the direction sensor and the traveling distance detecting means, which are the direction change detecting means, are used. Based on the information of a certain speed sensor, the displayed vehicle position is updated while determining whether the vehicle is off the road.

FIG. 3 is a diagram for explaining a conventional method of following the displayed vehicle position on the road. The change in azimuth makes positive rotation clockwise and negative rotation counterclockwise.
In FIG. 3, a black circle indicates the position of the own vehicle, and an arrow extending from the black circle indicates the traveling direction of the own vehicle. The vehicle position P2 at the next time point is the position where the vehicle has traveled on the road for the traveling distance obtained by the speed sensor in a certain traveling direction from the current vehicle position P1.
And

In FIG. 3, a, b, c and d indicate points (nodes) on the road map, and it is assumed that the vehicle position P2 has reached the vicinity of the point (node) b. At this time, in order to travel on the road represented by the point (node) b from the point (node) b, the own vehicle changes its own azimuth counterclockwise and changes to the azimuth θ2 to proceed. Suppose that it continued. As a result, whether or not the own vehicle is located on the road is determined by whether or not the road direction and the traveling direction of the own vehicle detected by the direction sensor at the current own vehicle position P2 match. It

However, the azimuth sensor has a detection error, and when checking whether the traveling azimuth of the vehicle and the road azimuth match, the azimuth sensor output has a certain allowable range θw.
When the road direction and the traveling direction of the vehicle match within this allowable range, it is determined that the vehicle is traveling on the road.

[0007]

In the past, the permissible range θw is often evenly distributed by (θw / 2) with respect to the traveling direction of the own vehicle with the traveling direction of the own vehicle as the center. The change in the road direction is small as at the own vehicle position P2, and the road direction is within the allowable range θw that sandwiches the traveling direction θ2 detected by the direction sensor, that is, θ2 ± (θw /
When it is within the range of 2), it is considered that the road direction and the traveling direction of the own vehicle are almost the same, and it is displayed on the road map that the own vehicle is traveling on the road. There is no problem.

However, the change in the road direction is large as at the own vehicle position P3, and in the process of changing the traveling direction, the road direction has an allowable range θ sandwiching the advancing direction θ3 detected by the direction sensor.
If it exceeds w, that is, θ3 ±
When the vehicle goes out of the range of (θw / 2), it may be determined that the vehicle is traveling on the road even though it is traveling on the road. There was a problem.

According to the present invention, when the road direction is changing, it is determined whether or not the displayed vehicle position deviates from the road in consideration of the change in the road direction, and the displayed vehicle position follows the road. It is an object of the present invention to provide a vehicle-mounted navigation device configured to do so.

[0010]

A vehicle-mounted navigation device according to the present invention has a predetermined allowable range set on the left and right sides of a vehicle signal direction detected by a vehicle traveling direction detection means to set a road direction. In the in-vehicle navigation device that determines whether or not the vehicle is traveling on the road of the displayed road map by determining whether or not it is within the set allowable range, the road direction changes. detects that the position the vehicle position to the location reached Then, by a value based on the difference between the moving direction of the change amount and the vehicle road directions, the travel direction of the vehicle in the traveling direction changing side of the vehicle of a road azimuth It is characterized in that it comprises an allowable range expanding means for expanding the allowable range to the side, and judges whether or not the road direction is within the expanded allowable range.

According to the in-vehicle navigation device of the present invention, the predetermined allowable range is set on the left and right sides of the own vehicle signal direction detected by the own vehicle traveling direction detecting means, and the road direction is set. in-vehicle navigation system tolerance there whether the determination to the vehicle in to determine whether or not the vehicle is traveling on a road of the road map displayed with the own the position where the road azimuth is changed When it is discovered that vehicle position reaches, by a value based on the difference between the moving direction of the change amount and the vehicle road directions, the travel direction of the vehicle in the traveling direction changing side of the vehicle road to azimuth side The allowable range of has been expanded,
It is determined whether or not the road direction is within the expanded allowable range. Therefore, even if the vehicle is traveling on the road when the change amount of the road direction is large and is within the predetermined allowable range, it is no longer determined that the vehicle is traveling away from the road. .

The vehicle-mounted navigation device according to the present invention is characterized in that the maximum value of the expanded permissible range is the road direction change amount.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A vehicle-mounted navigation device according to the present invention will be described with reference to an embodiment. FIG. 1 is a block diagram showing the configuration of a vehicle-mounted navigation device according to an embodiment of the present invention.

The on-vehicle navigation device according to the embodiment of the present invention relates to a plurality of map data including a road map stored by the connection of points expressed based on the latitude and the longitude and the relation between the map data. And a CD-ROM 1 in which data for indicating each map and data for each map are recorded, and for mounting a vehicle and receiving signals from GPS satellites to determine the position and traveling direction of the vehicle. The GPS signal receiving device 2, the azimuth sensor 3 including an angular velocity sensor or the like for detecting the relative traveling azimuth of the own vehicle, the positioning device 5 including the speed sensor 4 for detecting the speed of the own vehicle, and the CD-ROM 1 were read. A buffer memory 6 for storing map data over a plurality of display ranges.

The vehicle-mounted navigation device according to the embodiment of the present invention further includes a character generator 7 for displaying a character corresponding to the character code in the map data recorded in the CD-ROM 1, and a display. Enlargement, scrolling, so-called paging capable of switching display to the next screen are possible, and a road map based on the map data recorded in the CD-ROM 1 is displayed on the display device 10 in cooperation with the image memory 9. And a graphic display controller (hereinafter, referred to as GDC) 8 for.

Further, a vehicle-mounted navigation device according to an embodiment of the present invention includes a CPU 14, a touch panel 11 as an input device, a ROM 12 in which programs of the CPU 14 are stored, a work area, and data at the time of calculation by the CPU 14. RAM 13 for temporarily storing Here, although the touch panel 11 is independently displayed, the display device 10 may be a so-called touch screen in which the touch panel is superimposed on the display screen.

Based on the program stored in the ROM 12, the CPU 14 receives a signal from the GPS signal receiving device 2, a signal from the azimuth sensor 3 and a signal from the speed sensor 4, and receives the vehicle position and the vehicle position at predetermined time intervals. The traveling direction of the vehicle is calculated, map data of a predetermined range including the calculated own vehicle position is read from the CD-ROM 1 and written in the buffer memory 6, and the own vehicle position is within a predetermined display position on the display device 10. The map data is read from the buffer memory 6, the GDC 8 is controlled to be converted into image data, which is then stored in the image memory 9. The character data corresponding to the character code in the map data is read from the character generator 7 and stored in the image memory 9. A display device 10 for displaying a map and characters based on the stored image data and character data together with the vehicle position. To be displayed.

The image memory 9 has a plurality of screens such as a screen for displaying the vehicle position mark, a screen for displaying a map including a road map, a screen for displaying facilities, a screen for displaying characters, and the like. With the storage capacity for the screen, the display of each screen is superimposed and displayed on the screen of the display device 10 under the control of the CPU 14 and the GDC 8.

The CPU 14 cooperates with the output from the positioning device 5 to detect the traveling azimuth of the own vehicle per unit time, the own azimuth detecting circuit 141, and the traveling distance per unit time and the integration thereof. And own vehicle mileage detection circuit 142
And a road direction change position for detecting that the own vehicle has reached a position near the road direction change position in cooperation with the road information from the road map stored in the buffer memory and the output of the own vehicle travel distance detection means 142. In cooperation with the outputs of the arrival detection means 143 and the road direction change position arrival detection means 143, only the value based on the difference between the change amount of the road direction and the traveling direction of the vehicle advances from the traveling direction of the vehicle. Functionally, an allowable range expansion circuit 144 that expands the allowable range of the road on the azimuth change side to the azimuth side and a road traveling determination circuit 145 that determines whether the road azimuth is within the expanded allowable range are functional. Be prepared for.

Here, the maximum value of the expanded allowable range is limited to the road direction change amount.

In the vehicle-mounted navigation device according to the embodiment of the present invention configured as described above, the positioning device 5 measures the position of the own vehicle and the heading of the own vehicle, and includes the measured position of the own vehicle. The map data in a predetermined range is read from the CD-ROM 1 and the buffer memory 6
The map data in the range where the vehicle position reaches a predetermined display position on the display device 10 is read from the buffer memory 6, converted into image data under the control of the GDC 8 and stored in the image memory 9. The character data corresponding to the character code in the map data is read from the character generator 7 and the map and characters based on the image data and the character data stored in the image memory 9 are displayed on the display device 10 together with the position of the own vehicle. It

The operation of the vehicle-mounted navigation device according to the embodiment of the present invention configured as described above will be described with reference to FIG.

Upon receiving the output from the direction sensor 3, the direction change amount dθ of the vehicle per unit time is calculated. In addition, the output from the speed sensor 4 is received to calculate the own vehicle traveling distance dl. In response to the output from the GPS receiver 2, the current position P0 of the vehicle and the traveling direction θ0 are calculated at predetermined time intervals. On the other hand, road information represented by the connection of points represented based on latitude and longitude is read from the map data stored in the CD-ROM 1.

In the vicinity of the vehicle position P0 calculated based on the output from the GPS receiver 2, the GPS receiver 2
The road matching the traveling direction θ0 calculated based on the output from is searched, and the displayed vehicle position is corrected so that the vehicle position is on the searched road. The corrected position of the vehicle is P1, and the traveling direction of the vehicle is θ1. The azimuth change amounts dθ and dl are used based on this time point.
Based on the traveling of the vehicle, the vehicle travels on the road from the vehicle position P1 for the traveling distance dl along the traveling direction θ1 of the vehicle. By continuing this traveling, the own vehicle reaches a position near the next point (node) b.

Traveling direction θ2 of the vehicle at the vehicle position P2
Is given by θ2 = θ1-dθ. Point (node) a
And the direction of the road determined by the point (node) b and the direction of the road determined by the point (node) b and the point (node) c are small, the same as in the conventional case. By giving the traveling direction a certain allowable range θw, it is determined that the vehicle has not left the road.

It is assumed that the host vehicle travels from the host vehicle position P2 via points (node) b, point (node) c and point (node) d. In this case, when the vehicle reaches the vicinity of the point (node) c, the azimuth of the vehicle is changed to θ3 (= θ2-dθ).
The change in direction between the road defined by the point (node) b and the point (node) c and the road defined by the point (node) c and the point (node) d is large, and the point (node) c and the point (node The road determined by (node) d and θ3 ± (θw /
Although deviating from 2), in the vehicle-mounted navigation device according to the embodiment of the present invention, the change amount of the direction of the road −D
An allowable range from the vehicle traveling direction θ3 to the azimuth side of the road, that is, the traveling direction θ of the own vehicle in this example, by a value α based on the difference between θcd and the amount of change in the traveling direction of the own vehicle − (θ3−θ2).
The allowable range to the left of 3 is expanded.

As a result, the permissible ranges centering around the vehicle traveling direction θ3 are − (θw / 2 + α) and θw / 2. Therefore, the allowable range on the road side defined by the point (node) c and the point (node) d is expanded from the own vehicle traveling direction θ3 to the range of (θw / 2 + α) in the counterclockwise direction, and the own vehicle position is the point ( The road direction determined by the node c and the point d is within the own vehicle traveling direction including the allowable range, and the vehicle has not left from the road determined by the point c and the point d. Will be determined.

If the allowable range is not expanded, the road defined by the point (node) c and the point (node) d exceeds the allowable range (θ3-θw / 2). Even if the vehicle has not left after traveling on the road, it is determined that it has left.
In the vehicle-mounted navigation device according to the embodiment of the present invention, such misjudgment does not occur.

Further, since the value of the allowable range to be expanded is the value α based on the difference between the change amount of the direction of the road and the direction of the own vehicle, even though the vehicle is running off the road. Also, there is no erroneous determination that the vehicle is running on the road.

At the point (node) b, the permissible range is-(θw / 2 + α) and θw around the vehicle traveling direction θ2.
However, in the above description of the point (node) b, the road defined by the point (node) a and the point (node) b and the road defined by the point (node) b and the point (node) c. The change in the azimuth between the two is small, and the change in the traveling azimuth of the host vehicle- (θ2-θ1) is also small. As a result, the value α of the expanded allowable range is a small value, and the expanded allowable range α is For simplicity, the vehicle heading θ is omitted.
The allowable range centering on 2 is described based on the cases of − (θw / 2) and θw / 2.

Further, in FIG. 2, it is assumed that the vehicle travels from the vehicle position P2 via points (node) b, point (node) c and point (node) e. In this case, when reaching the vicinity of the point (node) c, the direction of the own vehicle is changed to θ4 (= θ2
+ Dθ). Point (node) b and point (node) c
The change in direction between the road defined by and the road defined by the points c and e is large, and the road defined by the node c and the node e is θ3 ± ( Although it deviates from θw / 2), in the vehicle-mounted navigation device according to the embodiment of the present invention,
A permissible range from the vehicle traveling azimuth θ4 to the azimuth side of the road, that is, in this example, by the value α based on the difference between the change amount Dθce of the road direction and the change amount (θ4-θ2) of the traveling direction of the vehicle. The allowable range to the right with respect to the vehicle heading θ4 is expanded.

As a result, the permissible range around the vehicle traveling direction θ4 is -θw / 2 and (θw / 2 + α). Therefore, the allowable range on the road side defined by the point (node) c and the point (node) e is expanded from the own vehicle traveling direction θ4 to the range of (θw / 2 + α) in the clockwise direction, and the own vehicle position is set to the point (node). ) C and the point (node) e, the road direction is within the own vehicle traveling direction including the allowable range, and the vehicle has not left the road defined by the point (node) c and the point (node) e. Will be determined.

According to the vehicle navigation system according to the present invention described above, position the road azimuth is changed
To when detecting that the vehicle position has reached only a value based on the difference between the progress direction position variation and the vehicle road azimuth, azimuth side in the traveling azimuth changed side road vehicle from the traveling direction of the vehicle tolerance to is expanded, to be determined whether the road azimuth within enlarged tolerance there, the vehicle position is not separated from the road when the road azimuth is changed However, it is possible to obtain the effect that it is no longer discriminated that the player has left.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle-mounted navigation device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining the operation of the vehicle-mounted navigation device according to the embodiment of the invention.

FIG. 3 is a schematic diagram for explaining the operation of a conventional vehicle-mounted navigation device.

[Explanation of symbols]

1 CD-ROM 2 GPS signal receiver 3 Direction sensor 4 speed sensor 5 Positioning device 10 Display 12 ROM 13 RAM 14 CPU 141 Vehicle traveling direction detection circuit 142 Own vehicle mileage detection circuit 143 Road direction change position arrival detection circuit 144 tolerance range expansion circuit 145 Road discriminating circuit

Continuation of front page (56) Reference JP-A-3-200008 (JP, A) JP-A-8-334365 (JP, A) JP-A-8-334361 (JP, A) JP-A-8-334345 (JP , A) JP-A-8-334334 (JP, A) JP-A-8-240436 (JP, A) JP-A-5-61410 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G01C 21/00 G08G 1/0969 G09B 29/10

Claims (2)

(57) [Claims] 1. A predetermined allowable range is set to the left and right of the own vehicle signal direction detected by the own vehicle traveling direction detecting means, and whether or not the road direction is within the set allowable range. in-vehicle navigation system discriminated by the vehicle to determine whether or not the vehicle is traveling on a road of the road map displayed, and detects that the vehicle position to the position where the road azimuth is changed reaches then, Equipped with a permissible range expanding means for expanding the permissible range from the traveling direction of the own vehicle to the direction side of the road on the side where the traveling direction of the own vehicle is changed by a value based on the difference between the change amount of the road direction and the traveling direction of the own vehicle. A vehicle-mounted navigation device, which determines whether or not the road direction is within the expanded allowable range. 2. The in-vehicle navigation device according to claim 1, wherein the maximum value of the expanded allowable range is a road direction change amount.