JPH02130415A - Running path display device - Google Patents

Abstract

PURPOSE:To achieve a correction of the current position accurately by extracting a minimum necessary road alone on which a moving object is supposed to have run to be subjected to a matching processing. CONSTITUTION:When there is no branch within a fixed distance L from a setting point of a preceding estimated current position x', an estimated current position x is set at a position advanced by a fixed distance L according to the running of the moving body. When there are branches within the fixed distance L, estimated current positions x1, x2 and x3 are set separately for all of the branches. Then, it is judged whether a distance between an estimated current position set and the current position of a moving body displayed off the surface of the road as then calculated is within a specified allowable range or not, and an estimated current position within the range is selected to make a candidate for matching a road alone in which the estimated current position selected exists.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving route display device that displays the current position of a moving object such as a car on a screen on which a road map is displayed in advance.

Conventionally, as will be explained in detail later, when driving a car in an unfamiliar area, for example, in order to provide appropriate guidance so that the driver does not deviate from the planned course and get lost. As the vehicle travels, a distance detector detects the distance traveled according to the speed of the vehicle, and a direction detector detects the direction of travel, and based on these detected values, the vehicle's current position on the X-Y coordinates changes from moment to moment. A driving route that allows the driver to confirm the current position by determining the current position by sequential calculations and updating and displaying the calculated current position using point information on a screen on which a road map is displayed in advance. A display device has been developed.

However, in such a driving route display device, it is unavoidable that position errors occur due to factors such as the accuracy of each detection when detecting distance and direction according to the driving condition of the car, etc., and as the car etc. progresses, position errors occur. Therefore, as the errors accumulate, the updated and displayed current position gradually deviates from the road on the map, making it impossible to determine which road on the map the vehicle is traveling on. There is.

Therefore, by matching the road pattern on the map with the travel trajectory pattern obtained by storing and retaining the current position data that is updated sequentially as the vehicle travels, it is possible to eliminate errors on the road. It is conceivable to have the current position that has deviated be corrected. In other words, all roads are extracted from the road network in the vicinity of the current location, and the compatibility between the pattern of each road and the pattern of the travel trajectory of a car, etc. is examined to find the pattern with the highest matching rate. The road you are driving on is considered the road you are currently driving on.

The display position of the current position is moved to the matching road.

However, if such a correction method is used, if the roads in the vicinity of the current location are complex5, all the roads are extracted and each road pattern is compared with the pattern of the travel trajectory of a car, etc. It takes a lot of time to perform matching processing.

l blur The present invention has been made in consideration of the above points.

When correcting the current position of a moving object that has deviated from the road due to an error by matching the moving trajectory pattern of the moving object with the road pattern on the map, To provide a travel route display device that extracts only the minimum necessary number of roads that may be lost, performs efficient matching processing, and allows accurate correction of the current position of a moving object. be.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of the configuration of a travel route display device according to the present invention. 1 For example, it is a photoelectric type, electromagnetic type, or mechanical contact type that outputs a pulse signal for each unit travel distance according to the rotation of a car tire. Distance sensors 1 and 1 Count the number of pulse signals from the direction sensor 2, which outputs a signal proportional to the amount of direction change as the car travels, and the distance sensor 1, which is composed of a gyroscope that detects changes in angular velocity in one direction, for example, when the car is running. The distance traveled by the vehicle is measured, and the position on the X-Y coordinates for each unit distance traveled by the vehicle is determined by successive calculations by calculating the change in the traveling direction according to the output signal of the direction sensor 2, and A signal processing device 3 consisting of a CPU that performs centralized control of the entire system, a program ROM, a control RAM, etc., and data on positions on x-y coordinates that change every moment determined by the signal processing device 3 are sequentially stored. and a travel trajectory storage device (RAM) 4 that holds the finite continuous position information corresponding to the current position of the vehicle, and a map information storage medium 5 in which a plurality of map information is stored in advance in file units. A storage medium playback device Ef6 selectively reads a necessary map file from the storage medium 5, displays a map surface image on the screen according to the read map file, and stores the map image in the travel trajectory storage device 4. A display bag that constantly updates and displays the car's current location, previous travel trajectory, and current direction of travel on the same screen based on the location data! i! 17, gives operation commands to the signal processing device 3, selects and specifies the map to be displayed on the display bag [7] and sets the starting point of the vehicle on the displayed map, and also controls the displayed map and driving direction. It is comprised of an operating device 8 that can appropriately change the display format settings such as changing the direction of the trajectory, shifting its display position, partially enlarging display of the map and traveling trajectory, and selecting the display scale ratio. .

With this configuration, the selectively read map is displayed on the screen of the display device 7, and the signal processing device 3 presets the map according to the vehicle travel from the starting point set on the map. The current position on the X-Y coordinates is calculated every moment according to the scale factor of the map, and the calculation results are sequentially sent to the travel trajectory storage device 4 to update its memory contents. The stored contents are constantly read out and sent to the display device 7. As a result, as shown in FIG. 2, the display bag [7 has a display mark Ml indicating the current position of the vehicle on the map displayed on its screen, a display mark M2 indicating the direction of travel of the vehicle at the current position, and A driving trajectory display mark M3 from the starting point S to the current position is displayed in a simulated manner following the driving state of the automobile.

The above configuration and operation are the same as the conventional travel route display device described at the beginning.

Therefore, in such a driving route display device.

As shown in Figure 3, due to the cumulative error mentioned above, the current position and the travel trajectory up to that point gradually deviate from the road on the map as the car travels, and eventually the current position of the car deviates from the road on the map It becomes impossible to judge which point the vehicle is traveling.

In the present invention, in such a driving route display device, under the control of the signal processing device 3, when the current position of the moving object and the driving trajectory up to that point deviate from the road on the map,
The pattern of each road in the vicinity is matched with the pattern of the moving trajectory of the moving object, and the road on which the pattern is matched is regarded as the road on which the moving object is currently traveling. The display position of the travel trajectory is corrected.

In this case, especially in the present invention, when matching the traveling trajectory pattern of the moving object with the road pattern, the road candidates to be matched with the pattern are selected to the minimum necessary as follows. The present invention is characterized in that it reduces the burden of matching processing.

First, the traveling distance of the moving object is set to a constant value, and therefore the estimated current position of the moving object is set on the road on which the moving object is currently traveling and on all roads branching from the road on the map.

At that time, as shown in Fig. 4(a), the previous estimated current position 1i! If there is no branching road within a certain distance l- from the set point 2X', the estimated current position rnx is set at a position that has progressed by the certain distance as the moving object travels. Further, as shown in FIG. 4(b), if there is a branch road within the certain distance ML, all of the branch roads have the estimated current positions xi, x2, . Set x3 respectively. Here, Q 1+Q2=Q 1+Q3=Q 1+Q
There is a relationship of 4=L.

The estimated current position is set every time the distance sensor 1 detects that the moving object has traveled a certain distance WIL. This is automatically performed by the processing in the signal processing device 3 according to the following. The setting of the estimated current position may be performed by sequentially setting the estimated current position every predetermined time period as the moving object travels, without depending on the distance traveled by the moving object. It is also conceivable to make the setting of the estimated current position [1] variable depending on the traveling condition of the moving object. Position data of each road on the X-Y coordinates is stored in the map information storage medium 5.

Next, it is determined whether the distance between the estimated current position set as described above and the current position of the moving object calculated at that time and displayed off the road is within a predetermined tolerance range. Then, the estimated current position within the range is selected, and only the roads on which the selected estimated current position exists are candidates for matching.

For example, given the relationship shown in Figure 5, the estimated current position x (
xi, x2. x3) and the current location IP as D (
Di, D2. D3), select the estimated current position that satisfies the following relationship:

Here, M is a preset tolerance range, for example, 5
It is set to about 0m. α is a coefficient related to the positional accuracy when the traveling distance of the moving object is used as a parameter, and is set to 1, for example, about 5%. Also, for L, it is 100
It is set to about m.

In this case, it may be possible to select an estimated current position that is set on a road whose direction is within a certain allowable angular difference with respect to the traveling direction of the mobile object's current position IP. .

However, if the value of 1M is set relatively small in the relationship shown in FIG. 5, only x2, for example, is selected as the estimated current position that satisfies the condition of equation (1), and the estimated current position 1tx2 exists. The road is considered as a candidate road to be subjected to matching processing.

Therefore, according to the present invention, even if there are many roads in the vicinity of the current location that are off the road, the minimum number of road candidates that have a high probability of being matched for matching processing is selected. Therefore, the burden of matching processing can be effectively reduced.

Furthermore, in the present invention, when matching the traveling trajectory pattern of a moving object and the candidate road pattern, the matching process is performed sequentially every time the moving object travels a certain distance and the estimated current position is set. Therefore, the amount of change in direction of the traveling trajectory of the moving object is constantly monitored, and when the value that integrates the amount of direction change exceeds a certain value, a significant change in the shape of the traveling trajectory is detected. It is assumed that this has occurred, and at that time, a matching process is executed at once according to the pattern of the travel locus of the moving object during the previous integration period.

That is, as shown in Fig. 6, for each fixed travel distance Q of the moving body, the angle wi (i==1.2° 3,・
), and the integrated value W of the amount of direction change is calculated sequentially according to the following formula.

w=ffi1w, -W,l (n=1.2,3
．． -)...(2) i-l l◆11 When the total amount W of the calculated direction change exceeds a preset value, the starting point a (previous The travel trajectory up to (the matching processing point) is extracted as the target of the current matching processing.

Therefore, if the extracted pattern is matched with the road according to the traveling trajectory of the moving object that has significant characteristics, the number of matching processes will be reduced overall, and the matching will be performed with high accuracy according to the characteristics of the pattern. It becomes possible to perform efficient matching processing. At this time, the road pattern to be matched is 1. For example, as shown in FIG. Cut out a road pattern that connects a plurality of past set points of estimated current positions [X' up to S.

In addition, if you want to cut out a road pattern with multiple estimated current positions and perform the matching process all at once, each estimated current position that satisfies the relationship of the (+) formula is selected as described above. At each point in time, the distance between the current position of the moving object and the estimated current position set on the road gradually increases as the moving object progresses. It is necessary to increase the value of M in equation (1) as the process progresses.

In addition, in the present invention, when matching the extracted traveling locus pattern of the moving object with the pattern of the candidate road cut out as described above, the processing in the signal processing device 3 is performed as shown in FIG. 8(a). As shown, the traveling trajectory RP
The pattern of the candidate road KP is approximated as a broken line by line segments of unit length, and the pattern of the candidate road KP is similarly approximated as shown in Fig. 8 (b
), the line segment is approximated by a line segment of unit length, and
Matching is performed using a vector sequence of each line segment approximated by a broken line.

However, by matching the travel trajectory of a moving object and the road on the map using each pattern that approximates a broken line under the same conditions, it is easy to compare the direction and position of each corresponding line segment. The matching process can be easily performed with high precision.

The specific matching process is performed as follows.

First, the positional correlation between the travel locus pattern approximated by a broken line using line segments of unit length and the candidate road pattern is determined. At that time, the travel trajectory pattern is rotated in a predetermined manner to match the directionality of the road pattern, and then the distance between the chain points of each corresponding line segment between the travel trajectory pattern and the road pattern is integrated. Let it be a correlation of position.

That is, as the first step, the vector sequence obtained by the broken line approximation of the traveling trajectory is (11, 12, J3°..., in).
The vector sequence approximated by the broken line of the candidate road is (r 1
*T2. r 31 ...+ r n), (I sll = I s21 =-= I snl
= I rl= l r21 =-= I rnl)
, the rotation angle θ of the vector sequence of the traveling trajectory is determined according to the following equation.

θ='Lω(i)-cos' (Si-ri/ I s
i l ·l r i l ) t1 × 1/, ω(i) ... (3) 1; pupil Here, ω(i) is a weighting function.

As a second step, the locus vector sequence is rotated according to the rotation angle O using a linear equation.

Note that by performing such rotation processing on the vector sequence of the travel trajectory, it is possible to correct the direction detection error as a result.

As a third step, a positional correlation value f is determined according to the following equation according to the rotationally processed traveling locus vector sequence and the road vector sequence.

Next, taking into account the distance detection error when calculating the current position [iP] of the moving object, a road vector is obtained by extending the starting position X of the candidate road by a certain distance + δ (several tens of meters) according to the road pattern. In the same manner as described above, the correlation value f of the position with the vector sequence of the travel trajectory is determined using the vector sequence of the road whose leading position of the candidate road is shortened by a certain distance -δ according to the road pattern.

Alternatively, while shifting the leading position of the candidate road by a fixed distance δ, the correlation value f between each candidate road whose leading position has been shifted and the corresponding travel trajectory is determined.

Finally, the smallest correlation value f is selected, and when the selected correlation value f is less than a certain reference value, it is determined that matching has been achieved. As shown in the figure, after moving the traveling trajectory RP in parallel so that the current position [P of the traveling trajectory is located in the order of the matching road pattern ff1 (for example, X + δ), Rotate by angle O around point P and match it to the matched road.

By performing such a matching process, the display position of the current position 1i[P of the mobile object that has deviated from the road on the map and the travel trajectory up to it will be corrected.

In performing the above matching process, in particular, in the present invention, when the extracted traveling trajectory of the moving object and the corresponding candidate road are approximated by line segments of unit length, the length of the line segment is The present invention is characterized in that the distance is set to be equal to the constant distance δ when performing the matching process while shifting the leading position of the candidate road by a constant distance δ.

However, if such a measure is taken, the starting position of the candidate road is shifted by a certain distance δ, and the original candidate road, the candidate road whose starting position has been shifted, and the driving trajectory are each converted into lines of unit length. After making a broken line approximation by
When calculating each correlation value f, the process can be performed easily.

In other words, if the length of the line segment that approximates the candidate road and the travel trajectory as a broken line is different from the constant distance δ, the candidate road whose leading position is shifted by a certain distance δ is again approximated as a broken line using a line segment of unit length. Then, it becomes necessary to recalculate the position data of the vector sequence based on the line segment of each unit length.

However, if the length of the line segment approximating the candidate road and the travel trajectory as broken lines is the same as the constant distance δ, then the original candidate road and the travel trajectory before shifting the starting position can be divided into unit-length line segments. Each data approximated by a broken line is processed using a signal processing bag T/! Once stored in the internal memory of 13, the position data of the vector sequence when the candidate road whose starting position is shifted by a certain distance δ is again approximated by a line segment of unit length can be used to calculate the starting position of the candidate road. You can now easily obtain it from the data stored in memory without having to recalculate it every time you shift it.

It becomes possible to significantly reduce the calculation required for matching processing.

As described above, the driving route display device according to the present invention can extract only the minimum number of roads that are thought to have been traveled by a moving object and use them as targets for matching processing, and can perform efficient matching processing. can be done quickly,
This has the excellent advantage that the current position can be corrected accurately.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing an embodiment of a travel route display device according to the present invention, FIG. 2 is a diagram showing an example of a display screen in the same embodiment, and FIG. 3 is a diagram showing a moving object. A diagram showing a state in which the current position of is displayed off the road, Figure 4 (a),
(b) is a diagram showing how the estimated current position of a moving object is set on the road every certain distance traveled, and Figure 5 shows the current position of a moving object that has deviated from the road and the estimated current position set on the road. A diagram showing the relationship with the estimated current position, FIG. 6 is a diagram showing an example of a state of change in direction in the travel trajectory of a moving object, FIG. 7 is a diagram showing a state of extraction of candidate road patterns to be matched, and FIG. Figure (a) is a diagram showing a state in which the traveling locus pattern of a moving object is approximated by a line segment of unit length,
Figure 8(b) is a diagram showing a state in which the road pattern is approximated by line segments of unit length, and Figure 9 is a diagram showing a state in which the current position and traveling trajectory of the moving object are matched to the matched road. FIG. 1...Distance sensor 2...Direction sensor 3...Signal processing device 4...Travel trajectory storage device 5...Map information storage medium 6...Storage medium playback device 7...Display device 8.・・Operation device

Claims (1)

[Claims] While detecting the traveling distance and direction of the moving object, the current position that changes every moment as the moving object is calculated is calculated sequentially, and the calculated current position data is stored and retained to determine the moving trajectory of the moving object. In a system in which the current position of a moving object is updated on a screen on which a road map is displayed, each time the moving object travels a certain distance, the road on which it is currently traveling on the map and the roads branching from that road are displayed. means for setting the estimated current position of the moving object at the same distance interval on the road, and a means for setting the estimated current position of the moving object on the road each time the moving object travels a certain distance and the current position of the moving object at that time. means for determining whether or not a predetermined positional relationship is established between them, and selecting an estimated current position at which the relationship is established; means for cutting out a candidate road that connects the selected estimated current positions; and means for approximating the cut out candidate road and the travel trajectory of the corresponding moving object using line segments each having a unit length;
The top of the candidate road approximated by the broken line is shifted by a line segment of the unit length, and the correlation values with the travel trajectory of the moving object approximated by the broken line are calculated, and the one with the highest calculated correlation value is taken as the one between the two. A travel route display device comprising means for matching patterns and means for correcting the current position of a moving object so that it is at the beginning of the matched road pattern.