JP3205800B2 - Current position display device of moving object - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving body current position display device for displaying the current position of a moving body on a road map projected on a screen in advance while obtaining the current position of the moving body.

[0002]

2. Description of the Related Art Conventionally, when driving a moving body such as a car in an unguided area, a distance sensor and a distance sensor have been provided so as to provide appropriate guidance so that the driver does not get out of the planned course and get lost. While detecting the traveling distance and traveling direction of the moving body using the direction sensor,
Driving by calculating the current position on two-dimensional coordinates by calculation and displaying the current position, which constantly changes with the traveling of the moving body, on a road map projected on the screen in advance while sequentially updating the point information with point information. 2. Description of the Related Art A current position display device for a moving object has been developed which enables a user to confirm a current position.

However, in such a moving body current position display device, it is unavoidable that a position error occurs due to factors such as the accuracy of the distance sensor and the direction sensor and the accuracy of calculation using the significant digits when calculating the current position. As the traveling of the moving object progresses, the error is accumulated, and the current position displayed on the screen gradually deviates from the road on the map, and it is determined which road on the map the vehicle is traveling on There is a problem that it becomes impossible to do.

[0004] Even if there is no error in the calculated current position of the moving object, if the current position is displayed on the map itself, the current position displayed on the screen deviates from the road on the map. Will be lost.

[0005] Therefore, conventionally, in order to correct the current position deviating from the road on the map, the data of the current position which is sequentially updated according to the road pattern on the map and the traveling of the moving object are stored and held. A matching process with the obtained traveling locus pattern is periodically performed so that the traveling locus is adjusted on the matched road to correct the current position of the moving body (for example, Japanese Patent Application Laid-Open No. Hei 4-41817). Reference).

[0006]

The problem to be solved is that a pattern of a road on a map and a traveling locus of a moving object are matched, and the traveling locus is matched with the matched road. When correcting the current position of a moving object with, generally, the higher the accuracy of pattern matching, the greater the amount of computation required for the matching process. In such a case, an enormous amount of calculations must be performed in a short time, and the processing load on a computer or the like increases.

In addition, when matching patterns,
Conventionally, the matching between the road on the map and the travel locus of the moving object is performed by using a pattern obtained by approximating the traveling trajectory of the moving object with a line segment, so that the accuracy of the current position of the moving object corrected by the matching decreases. It is to be.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the current position of a moving body is corrected with high accuracy by matching both running trajectories and road patterns on a map without approximating each pattern. , In order to effectively reduce the amount of calculation for the matching and to perform the processing at a high speed,
A road shape that matches the shape of the traveling locus of the moving object obtained by sequentially storing data of the current position of the moving object in the memory by a predetermined algorithm using the non-directional generalized Hough transform is included in the road map. Search from
The traveling locus is adjusted to the searched road shape portion to correct the current position of the moving body that is off the road on the map.

[0009]

FIG. 1 shows an example of the configuration of a moving body current position display device according to the present invention. For example, a distance sensor 1 for outputting a pulse signal for each unit traveling distance in accordance with the rotation of a tire of the moving body; For example, a direction sensor 2 that outputs a signal proportional to an amount of change in direction along with the traveling of the moving body that detects a change in the angular velocity in the yaw direction, and counts the number of pulse signals from the distance sensor 1 to measure the traveling distance of the moving body. In addition, the current position on the XY coordinates for each constant traveling distance of the moving body is obtained by successive calculation to obtain the current position of the moving body by calculating the change in the traveling direction according to the output signal of the direction sensor 2. A signal processing device 3 composed of a microcomputer for controlling the entire device, and a constantly changing X-value obtained by the signal processing device 3
A travel locus storage device 4 for sequentially storing data of the current position of the position on the Y coordinate and storing the data as finite continuous position information of the moving object, and a map information storage medium 5 in which road map information is stored in advance. And a storage medium reproducing device 6 for selectively reading road map information of a required area from the storage medium 5, and displaying a predetermined road map on a screen based on the read map information, and displaying the road map information on the screen. A display device 7 for updating and displaying the current position of the mobile object on the road map thus updated, as necessary, along with the traveling locus and the traveling direction of the mobile object at the current position, as the mobile device travels; In addition to giving an operation command to the device 3, the user selects and specifies a map to be displayed on the display device 7 and sets a starting point of the moving object on the displayed map. Selectively given a display command such as marks,
An operation device 8 that can appropriately change the direction of the displayed map and traveling locus, shift the display position, partially enlarge the map and traveling locus, and change the setting of the display form such as selection of the display scale factor; It is constituted by.

[0010] In the above configuration, the map selectively read out is displayed on the screen of the display device 7 and the signal processing is performed in accordance with the traveling of the moving body from the starting point set on the map. The current position on the XY coordinates is calculated by the device 3 in accordance with a preset scale of the map, and the calculation result is sequentially transmitted to the travel locus storage device 4 to update the stored content. At the same time, the stored contents are read out and sent to the display device 7.

As a result, for example, FIG.
As shown in the figure, on the map displayed on the screen, a display mark M1 indicating the current position of the moving object, a display mark M2 indicating the traveling direction of the moving object at the current position, and the starting point S
From the current position to the current position are displayed in a simulated manner following the traveling state of the moving body.

The above configuration and operation are the same as those of the conventional moving object current position display device described at the beginning.

Accordingly, in such a current position display apparatus for a moving body, as shown in FIG. 3, the current position and the running locus up to that point are shifted from the road on the map as the moving body moves as shown in FIG. It gradually deviates greatly, and eventually it becomes impossible to determine which point on the map the mobile object is currently traveling.

The present invention relates to such a present position display device for a moving object, wherein the signal processing device 3 matches the shape of the traveling trajectory of the moving object by a predetermined algorithm using a non-directional generalized Hough transform. A means for searching for a road shape from a road map and a means for adjusting the current position of a moving object deviating from a road on a map by matching a running locus with a portion of the searched road shape. Like that.

Now, for example, as shown in FIGS. 4 and 5, the displacement of the position on the XY coordinate between the traveling locus LP of the moving body and the road RD on the map having the same shape as the locus LP is represented by p ( X-axis direction shift), q (Y-axis direction shift), φ
(Rotational deviation), each point ni (x _ni , y _ni ) (i = 1, 2, 2) set on the traveling locus LP.
(X ′, y ′) on the road RD corresponding to (3,..., N)
Is given by:

[0016]

(Equation 1)

A three-dimensional space composed of the search parameters p, q, and φ is as shown in FIG. 6, and the space figure is obtained by converting a road map into a point _ni and a rotational deviation φ on a traveling locus LP.
Are shifted simultaneously by the shift vector sv according to the first term on the right side of the above equation.

[0018] Then, according to non-oriented type generalized Hough transform, the search parameters p, q, in three-dimensional space consisting of phi, the space figure formed by selecting each point n _i on the traveling locus LP are concentrated The values of the search parameters p, q, and φ are obtained from the position of the point in space.

The theory of the non-directional generalized Hough transform itself is described in a paper published at the 1975 IEEE academic meeting.
It is known as Merlin-Farber theory.

In the present invention, the traveling trajectory L of the moving object is determined by a predetermined algorithm using the non-directional generalized Hough transform.
A feature is that a road RD that matches the shape of P is searched from a road map.

At this time, for example, p = 4Km, q = 4K
A search parameter space is set with m and φ = 360 °, and a road RD that matches the shape of the traveling locus LP of the moving object having a length of about 2 km is searched from the road map.

The specific algorithm using the non-directional generalized Hough transform is specifically executed as follows.

As shown in FIG. 7, the search parameters p,
After dividing the three-dimensional space consisting of q and φ by the cells consisting of Δp, Δq, and Δφ, one cell is selected, and corresponding to one point on the traveling trajectory LP, the selected cell is its response within the area of the road map examines whether the road is not walk by its votes 1 if there is a road in addition to the area to do it for all points n _i on the travel locus LP The total number of votes of the selected cell is obtained, and the above processing is performed on all the cells in the three-dimensional space. From the position of the cell with the largest number in the three-dimensional space, search parameters p and
Find each value of q and φ.

FIG. 8 shows an area on the road map corresponding to one cell in the three-dimensional space consisting of the search parameters p, q, and φ (shown by oblique lines in the figure). In this case, the number of votes is added to the corresponding cell.

Then, by obtaining the values of the search parameters p, q, and φ, a road RD that matches the shape of the traveling locus LP of the moving object is searched from the road map.
Travel locus LP so as to match the searched road RD
Is translated and rotated to correct the current position of the moving object that is off the road on the map.

Thus, according to the present invention, the traveling locus LP of the moving body that is actually obtained can be obtained without approximating the traveling locus LP of the moving body with the road RD on the road map by any line segment. Since the road RD on the road map that matches the shape is used as it is, and the traveling locus LP is matched with the searched road RD, the current position of the moving object is corrected. The correction of the current position can be performed with high accuracy.

The procedure for calculating the number of votes of a cell is performed, for example, as follows.

The values of the shift vector sv according to the first term on the right side of the above equation with respect to all the points _ni and the rotational deviation φ on the traveling locus LP are calculated in advance and registered in the main memory of the signal processing device 3. Draw a road map on the main memory using the drawing chip. At this time, 4K is used by using a traveling locus LP having a length of 2 km.
An 8 km square road map is drawn so that m squares can be searched. At a predetermined resolution Δp = Δq, data is transferred from the road map one byte at a time to the OR processing register in accordance with the shift vector, and the area of the road map spread by the rotational deviation Δφ is OR-processed. . The value of the OR processing register is shifted and checked, and if the value is 1, the number of votes is counted by incrementing the corresponding count register. Check the value of the count register and executing repeatedly and the process for all points n _i on the traveling locus LP, its value is stored in memory is larger than the threshold value. The above-mentioned processes are repeatedly executed by the number of 1/8 cells in the search parameter space.

In the present invention, a wide search parameter space is divided into small cells in order to improve accuracy.
If voting is performed for all the cells, the amount of calculation for the cell becomes large and a large memory capacity and processing time are required. To suppress the amount of calculation, the following hierarchical processing is performed. Thus, the memory capacity is reduced and the processing speed is increased.

That is, a cell having a maximum value of the number of votes is obtained by setting a large cell size, and the obtained cell is further divided into smaller cells. Hierarchical processing for obtaining a small cell is performed, and the values of the parameters p, q, and φ are obtained from the finally obtained minimum cell position.

FIG. 9 shows the state of hierarchical division of cells at that time. Here, cell division is performed in three stages, the cell size is C1 in the first stage, and the cell size is in the second stage. The size is C2, and the cell size is C3 in the third stage.

Specifically, p = 4 km, q = 4 km, φ
= 360 ° to set the search parameter space and 2K
When searching a road map for a road RD that matches the shape of the traveling locus LP of the moving object having a length of about m, the size of the cell C1 is set to Δp = Δq = 160 m, Δφ =
4 ° and the size of cell C2 is Δp = Δq = 40
m, Δφ = 1 °, and the size of the cell C3 is set to Δp = Δ
Set q = 10 m and Δφ = 0.25 °.

Thus, according to the present invention, by performing hierarchical processing over a wide search parameter space, it is possible to effectively reduce the memory capacity and speed up the processing while effectively suppressing the calculation amount. Thus, the road RD that matches the shape of the traveling locus LP of the moving object can be accurately searched from the road map.

[0034]

As described above, in the moving object current position display apparatus according to the present invention, the traveling locus of the moving object and the road on the road map are not actually approximated by a line segment or the like without any line segment. Using the shape of the traveling trajectory of the moving object as it is, searching for a road on the road map that matches it,
Since the current position of the moving object is corrected by adjusting the traveling locus to the searched road, there is an advantage that the current position can be corrected with high accuracy.

Further, in the present position display apparatus for a moving object according to the present invention, a road that matches the shape of the traveling locus of the moving object is searched from the road map by hierarchical processing. This has the advantage that the memory capacity can be reduced and the processing speed can be effectively reduced while effectively suppressing the calculation amount, and the search can be accurately performed over a wide range of the road map.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a present position display device of a moving object according to the present invention.

FIG. 2 is a diagram showing an example of display contents in the embodiment.

FIG. 3 is a diagram showing a state in which a traveling locus deviates from a road on a map.

FIG. 4 is a diagram illustrating an example of a traveling locus.

FIG. 5 is a diagram showing a correlation between the position of a road on the road map and the travel locus of FIG. 4;

FIG. 6 is a diagram showing a search parameter space.

FIG. 7 is a diagram showing a state in which a search parameter space is divided into cells.

FIG. 8 is a diagram showing an area on a road map corresponding to one cell in a search parameter space.

FIG. 9 is a diagram showing a state of hierarchical division of cells in a search parameter space.

[Description of Signs] 1 Distance sensor 2 Direction sensor 3 Signal processing device 4 Travel locus storage device 5 Map information storage medium 6 Storage medium reproduction device 7 Display device 8 Operation device

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01C 21/00 G08G 1/0969 G09B 29/10

Claims (3)

(57) [Claims] 1. While detecting a traveling distance and a traveling direction of a moving body, a current position on a two-dimensional coordinate which changes with the traveling of the moving body is sequentially obtained according to the respective detection results, and the storage medium is previously determined. A non-directional generalized Hough transform is performed by a current position display device of a moving body that updates the display of the current position of the moving body on a screen on which map data is read out and a predetermined road map is projected. Means for searching a road map for a road shape that matches the shape of the traveling trajectory of the moving object obtained by sequentially storing data of the current position of the moving object in the memory by the predetermined algorithm used; Means for correcting the current position of a moving object that has deviated from the road on the map by adjusting the traveling locus to the portion of the road shape that has been set. Characteristic current position display device for moving objects. 2. As a predetermined algorithm using a non-directional generalized Hough transform, a displacement on a XY coordinate between a traveling locus and a road shape corresponding to the traveling locus is represented by p (displacement in the X-axis direction). , Q (Y axis direction deviation), φ (Rotation deviation)
, The three-dimensional space composed of the search parameters p, q, and φ is divided into cells, a plurality of points are set on the travel locus, one cell is selected, and one cell on the travel locus is selected. If there is a road in the area of the road map corresponding to the selected cell corresponding to the point, the number of votes is added to 1, and the process is executed for all points on the traveling locus to select the selected cell. Of the parameters p, q, and φ from the position in the space of the cell having the larger value among the total votes of each cell obtained by performing the above processing for all the cells. 2. The current position display device for a moving object according to the above item 1, wherein each value is obtained. 3. A cell having a large value of the number of votes is determined by setting a large cell size, and the obtained cell is further divided into smaller cells. 3. The method according to claim 2, wherein the values of the parameters p, q, and φ are obtained from the position of the finally obtained minimum cell by performing a hierarchical process for obtaining a small cell. Display device of the current position of the moving object.