JP2584303B2 - Travel route display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a traveling route display device for displaying a current position on a screen on which a map is projected in advance while obtaining a current position of a moving body such as an automobile.

2. Description of the Related Art Recently, as will be described in detail later, for example, when traveling a moving object such as a car in an unguided area, etc., in order to provide appropriate guidance so that the driver does not lose his way off the scheduled course. While detecting the traveling distance of the moving body with the distance sensor and the traveling direction of the moving body with the direction sensor, the current position on the two-dimensional coordinates of the moving body is calculated from the detected values as the traveling of the moving body. A travel route display device has been developed in which the current position of a moving object is updated and displayed on a map projected on a screen in advance, which is obtained cumulatively by arithmetic processing.

However, in such a traveling route display device, a position error due to each detection accuracy or the like in performing distance detection and direction detection according to the traveling state of the moving body cannot be denied, and the traveling of the moving body proceeds. Therefore, there is a problem that the error is accumulated and the current position deviates from the traveling course on the map, and it becomes impossible to determine on which road on the map the vehicle is traveling.

At this time, if a direction sensor based on a rate formula is used as the direction sensor that detects the angular velocity of the change in the yaw direction of the moving body and obtains the amount of change in the traveling direction, the direction detection error accumulates due to the influence of offset or the like. In addition, if a geomagnetic sensor that detects the traveling direction of a moving object by sensing geomagnetism is used, a temporary direction detection error occurs due to the influence of magnetic disturbance, and the type of direction sensor used The state of occurrence of the error in the current position of the moving object differs depending on the type of the moving object.

Conventionally, in order to correct the position error, a pattern matching between a road shape on a map and a traveling locus of a moving body obtained by storing and holding data of a current position sequentially updated according to the traveling of the moving body is performed. By calculating a correlation value between the two, the traveling locus is adjusted to the matched road, and the current position off the traveling course is corrected.

However, in order to match the pattern between the traveling trajectory of the moving object and the road shape in the map, the correlation value between the two is calculated at a single rate. Since the state of occurrence of the error of the current position of the body is different, it is impossible to perform an appropriate matching process that is actually appropriate.

Object The present invention has been made in consideration of the above points, and calculates a correlation value of a pattern between a road shape on a map and a traveling trajectory of a moving object, and matches the two to take a present value that is off the traveling course. It is an object of the present invention to provide a traveling route display device that appropriately performs a matching process in accordance with the type of a direction sensor to be used when a position and a correction are performed.

Configuration Hereinafter, an 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 traveling route display device according to the present invention, and a distance sensor 1 for detecting the traveling distance of a moving body.
And a direction sensor 2 for detecting a traveling direction of the moving body, and a position on a two-dimensional coordinate for each unit traveling distance of the moving body is sequentially calculated based on the outputs of the sensors.
And a signal processing device 3 comprising a microcomputer or the like for performing centralized control of the whole system, and data of the position on the two-dimensional coordinates that change every moment obtained by the signal processing device 3 are sequentially stored, and the current position of the moving object is stored. A travel locus storage device 4 that holds the information as finite continuous position information corresponding to the information, a map information storage medium 5 in which a plurality of digitized map information are stored in units of files, A storage medium reproducing device 6 for selectively reading a file of a map, a map image is displayed on a screen in accordance with the read map file, and a moving object is displayed on the basis of position data stored in a travel locus storage device 4. Display device that updates and displays the current position on the same screen as necessary along with the running trajectory and the current running direction so far. And an operation command to the signal processing device 3 to select and designate a map to be displayed on the display device 7 and to set a starting point of the moving object on the displayed map, and to give a display instruction such as a traveling locus. Give
An operation device 8 capable of appropriately changing the direction of the displayed map and traveling locus, shifting the display position, partially enlarging the map and locus, and changing the setting of the display form such as selecting the display scale. It is configured.

In such a configuration, as shown in FIG. 2, the selectively read map is displayed on the screen of the display device 7, and the vehicle from the starting point S set on the map is displayed. As the vehicle travels, a display mark M1 indicating the current position of the moving object on two-dimensional coordinates in accordance with the scale of the map set in advance by the signal processing device 3, and a display mark M2 indicating the traveling direction of the moving object at the current position. And a running locus display mark M3 from the starting point S to the current position is simulated and displayed following the running state of the moving body.

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

Therefore, in such a traveling route display device, the third
As shown in the figure, the current position and the traveling locus up to that point gradually deviate from the road on the map as the traveling of the moving object progresses due to the accumulated error described above. It becomes impossible to determine whether the vehicle is traveling.

In the present invention, the signal processing device 3 detects that the traveling locus deviates from the road by comparing the position data of the traveling locus of the moving object with the position data of the road on the map, and detects the departure of the deviated portion. By extracting a line segment of a candidate road having a pattern similar to the pattern of the traveling locus from nearby roads and calculating a correlation value of a pattern between the traveling locus of the deviated portion and the shape of the candidate road, The current position of the moving object is corrected by adjusting the traveling locus on the road on which the matching has been performed.

For example, as shown in FIGS. 4 (a) and 4 (b), as the correlation value of the pattern between the travel locus and the shape of the candidate road, the travel locus P of the moving object and the candidate road R extracted from the map are used. After approximating the broken line using the unit length vector V, as shown in FIG. 4 (c), the two are overlapped so that the leading Hp and Hr of the broken line approximated patterns P 'and R' coincide. Area A caused by displacement between the two when combined
1, A2, A3,..., The sum of the areas is calculated, and if the result is equal to or less than a predetermined threshold, the traveling locus P
The pattern matching between the pattern and the candidate road R is determined.

When the patterns P ′ and R ′ obtained by approximating the traveling locus P and the candidate road R by the unit length vector V are each folded, and the degree of matching is determined by superimposing the patterns P ′ and R ′, In addition to overlapping the heads Hp and Hr so that they coincide with each other, as shown in FIG. 5, the position Hr 'where the head Hr of the pattern R' of the candidate road is slightly extended and the pattern R 'of the candidate road are shown. If the degree of matching when the top Hp of the traveling trajectory pattern P 'coincides with the position Hr "where the top Hr is slightly reduced from the top Hr is matched, a more accurate matching process can be performed. Can be performed.

At this time, when a gyro-type or gas-type rate sensor is used as the direction sensor 2, the detection error of the direction accumulates due to the influence of an offset or the like. For example, as shown in FIG. The traveling locus P of the moving object displaced from the road R on the map is shown in FIG.
When the shifted traveling trajectory P is superimposed on the road R such that the current position Op at the tip of the traveling trajectory P is located at the current position Or of the actual moving body on the road R, the leading portion of the traveling trajectory P becomes smaller. It matches well with the shape of the road R, but its traveling locus P
, That is, the past locus, the deviation from the shape of the road R is greatly deviated.

Therefore, in the present invention, particularly when using a rate sensor as the direction sensor 2, when performing the above-described matching processing, when calculating the correlation value of the pattern between the traveling locus of the moving object and the shape of the candidate road, The calculation of the weighted correlation value from the current position to the past is performed, and the weight is reduced in the past.

More specifically, as described above, when the pattern P 'of the traveling locus approximated by the unit length vector V and the pattern R' of the candidate road are overlapped with each other, the areas A1 and A2 generated by the displacement between the two. , A3, ..., the weighting factor omega ₁ respectively _{an, ω 2, ω 3,} ..., after having multiplied the omega _n, the following equation (1)
As shown in the above, the sum is calculated, and if the result is equal to or smaller than a predetermined threshold value K, it is determined that the pattern matching between the traveling locus P and the candidate road R has been achieved. I have.

to _{ω 1 · A1 + ω 2 ·} A2 + ω 3 · A3 + ... + ω n · An ≦ K ... (1) FIG. 7 shows an example of characteristics of the weighting factor omega used in (1).

As described above, according to the present invention, when calculating the correlation value between the traveling locus of the moving object and the pattern of the road shape in the map, the latest traveling locus is emphasized, and the past traveling locus is more important. Since the correlation value is neglected, the matching process according to the characteristics of the direction sensor based on the rate equation can be optimally performed.

Further, when a geomagnetic sensor is used as the direction sensor 2, an error occurs in the direction detection temporarily due to a magnetic disturbance.

Therefore, in the present invention, particularly when a geomagnetic sensor is used as the direction sensor 2, when performing the above-described matching processing, when calculating the correlation value of the pattern between the traveling locus of the moving object and the shape of the candidate road, The weighting of the correlation value in a portion corresponding to the running locus when the sensor is subjected to magnetic disturbance is reduced.

At this time, for example, while monitoring the rate of change of the output of the geomagnetic sensor in the signal processing device 3, when the rate of change is greater than a certain value, the output state of the geomagnetic sensor becomes unstable and receives a magnetic disturbance. Is determined, the weight coefficient of the correlation value in that portion is determined according to the magnitude of the change rate of the output of the geomagnetic sensor when the disturbance is received.

More specifically, as described above, when the pattern P 'of the traveling locus and the pattern R' of the candidate road, each of which is approximated by the unit length vector V, are overlapped, the pattern corresponds to the area A3 caused by the displacement between the two. When it is determined that the geomagnetic sensor has received a magnetic disturbance in the portion of the traveling locus that has been determined, the weighting factor calculated according to the magnitude of the change rate of the output of the geomagnetic sensor at that time in the area A3 of the portion After multiplying by ω _x and performing a calculation as shown in the following equation (2), if the result is equal to or less than a preset threshold value K ′, the pattern of the traveling locus P and the candidate road R It is determined that matching has been achieved.

The _{A1 + A2 + ω x · A3} + ... + An ≦ K '... (2) FIG. 8, the change rate of the output of the geomagnetic sensor, i.e. the magnetic disturbance applied to the geomagnetic sensor size characteristics of the weighting factor omega _x issued comparatively accordance of An example is shown.

As described above, according to the present invention, when calculating the correlation value between the traveling locus of the moving object and the pattern of the road shape in the map, and when matching the two, when a magnetic disturbance is applied to the geomagnetic sensor, Since the weight of the correlation value corresponding to the traveling locus portion is reduced according to the degree of disturbance at that time, it is possible to optimally perform the matching process according to the characteristics of the geomagnetic sensor.

As described above, in the traveling route display device according to the present invention, when the current position sequentially updated and displayed from the road of the map projected on the screen according to the traveling of the moving body is shifted, the road shape and the traveling locus When calculating the correlation value of the pattern and correcting the current position deviating from the traveling course by matching the two, the correlation value is calculated according to the type of the direction sensor to be used, and the matching process is performed. It has the great advantage that it can be performed optimally.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a traveling route display device according to the present invention, FIG. 2 is a diagram showing an example of display contents in the embodiment, and FIG. 3 is a traveling locus deviating from a road on a map. FIGS. 4 (a) and 4 (b) are diagrams showing a state in which a traveling locus of a moving object and a candidate road extracted from a map are each approximated by a unit length vector, and FIGS. 4 (c) and 4 (c). ) Is a diagram showing a state in which a traveling locus pattern approximated to a folding line and a candidate road pattern are superimposed, and FIG.
FIG. 6A is a diagram showing a state in which a traveling locus pattern approximated to a broken line and a candidate road pattern are superimposed with their heads shifted, and FIG. 6A is a diagram in which the traveling locus of the moving body is displaced from the road on the map. FIG. 6 (b) shows a state in which the running locus shifted so that the current position of the tip of the running locus is located at the current position of the actual moving body on the road is superimposed on the road. FIG. 7 is a diagram showing an example of characteristics of a weight coefficient used for calculating a correlation value when using a rate type direction sensor. FIG. 8 is a diagram showing a weight coefficient used for calculating a correlation value when using a geomagnetic sensor. It is a figure showing an example of a characteristic. DESCRIPTION OF SYMBOLS 1 ... Distance sensor, 2 ... Direction sensor, 3 ... Signal processing device, 4 ... Traveling locus storage device, 5 ... Map information storage medium, 6 ... Storage medium reproduction device, 7 ... Display device, 8 ......
Operation device

Claims (2)

(57) [Claims] The present invention detects the current position of a moving object on a two-dimensional coordinate system, which is constantly changing, while detecting a traveling distance of the moving object by a distance sensor and a traveling direction accompanying the traveling of the moving object by a direction sensor based on a rate. The traveling locus of the moving object and the road shape in the map obtained by successively calculating and updating the current position of the moving object on a screen on which a road map is displayed in advance and storing and holding data of the current position are displayed. In a traveling route display device which calculates the correlation value of the pattern with the two, the two are matched, and the current position is corrected by adjusting the traveling locus on the road on which the matching has been taken. From the past to the past, perform cumulative addition of partially weighted pattern correlation values, and take measures to reduce the weighting in the past Driving route display device is characterized in that so as to make the calculations by the. 2. The method according to claim 1, further comprising: detecting a traveling distance of the moving body by a distance sensor and a traveling direction of the moving body by a geomagnetic type direction sensor; The traveling locus of the moving object and the road shape in the map obtained by successively calculating and updating the current position of the moving object on a screen on which a road map is displayed in advance and recording and holding data of the current position are obtained. In a traveling route display device that calculates the correlation value of the pattern and the two to match each other, and adjusts the current position by adjusting the traveling trajectory on the matched road, a geomagnetic type Means for monitoring the rate of change of the output of the direction sensor due to the above, and judging that a magnetic disturbance has been received when the rate of change becomes larger than a certain value. Means for reducing the weighting of the correlation value in the portion corresponding to the traveling locus according to the magnitude of the rate of change of the output of the direction sensor by the geomagnetic method when receiving magnetic disturbance. A driving route display device characterized in that: