JPH07109368B2 - Current position display of mobile - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a current position display device for a mobile body, which displays the current position of the mobile body on a road map previously projected on a screen while obtaining the current position of the mobile body.

Conventional technology Conventionally, for example, when driving a moving body such as an automobile in a non-guidance area, in order to provide appropriate guidance so that the driver does not get lost from the planned traveling course,
While detecting the traveling distance and the traveling direction of the moving body by using the distance sensor and the direction sensor, the current position on the two-dimensional coordinates is obtained by calculation, and the present position that changes momentarily as the moving body travels is calculated. The driver can confirm the current position by displaying the map information of the driving area read in advance from the map information storage medium and sequentially updating and displaying the point information on the road map displayed on the screen. A current position display device for a mobile body has been developed.

However, in such a current position display device for a moving body, it is unavoidable that a position error occurs due to the accuracy of each sensor of the distance sensor and the direction sensor and the calculation accuracy of the effective digit when calculating the current position. As the driving progresses, the error accumulates, and the current position displayed on the screen gradually deviates from the road on the map, and it is possible to judge which road on the map the vehicle is driving. There is a problem of being unable to do it.

Even if there is no error in the calculated current position of the moving body, if the map displaying the current position has deformation, the current position displayed on the screen may deviate from the road on the map. Become.

Therefore, in the past, in order to correct the current position deviating from the road on the map, the travel obtained by storing and holding the data of the current position which is sequentially updated according to the travel of the road pattern and the moving body on the map The matching process with the pattern of the locus is periodically performed to match the running locus on the matched road to correct the current position of the moving body (see JP-A-1-41817). .

As a road map used for the current position display device of such a moving body, it is desirable to use a detailed map that matches the actual road condition in terms of matching accuracy. If you use a map,
The number of roads to be subjected to the matching processing increases and the processing load increases, so that the matching processing takes time, and the processing cannot keep up depending on the traveling state of the mobile body.

In addition, it is difficult to create a detailed road map over a wide area nationwide, and the capacity of a storage medium for storing such map information becomes enormous.

The present invention has been made in consideration of the above points, and a main road map and a detailed road map in the same area such as an urban area included in the main road map are prepared in advance, and the matching processing time is set to the moving object. Depending on whether or not to follow the running of
The present invention provides a current position display device for a mobile body, which is adapted to appropriately switch between a main road map and a detailed road map so as to be optimal for matching processing.

Configuration 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 current position display device for a moving body according to the present invention. For example, a speed sensor 1 for detecting the traveling speed of the moving body and a moving body for detecting the angular velocity of a change in the yaw direction A rate-based direction sensor 2 that outputs a signal proportional to the amount of change in direction with traveling, and the traveling speed of the moving body is measured by integrating the traveling speed detected by the speed sensor 1 with time. The present position of the moving body on the XY coordinates for each unit traveling distance is sequentially obtained by calculating the amount of change in the moving direction of the moving body by time-integrating the detected angular velocity, and the current position of the moving body is obtained. The signal processing device 3 including a microcomputer for controlling the entire display device and the traveling of the moving body determined by the signal processing device 3 were set. And X-Y sequentially stores the data of the current position on the coordinate, the travel locus storing unit 4 for storing and holding it as a finite continuous positional information of the movable body that constantly change I,
Based on the map information storage medium 5 in which information of a plurality of road maps is stored in advance, the storage medium reproducing device 6 for selectively reading the road map information from the storage medium 5, and the read map information. A predetermined road map is displayed on the screen, and the current position of the moving body is displayed on the road map displayed on the screen along with the traveling locus and the traveling direction of the moving body at the current position, if necessary. According to the display device 7 and the signal processing device 3, an operation command is given, and the selection and designation of the map to be displayed on the display device 7 and the starting point of the moving body on the displayed map are performed. Selective display commands such as running locus, direction change of displayed map and running locus, shift of its display position, partial enlarged display of map and running locus, table It is constituted by an operating device 8 to change settings of the display form, such as the scale factor selection can be performed appropriately.

With such a configuration, the map read from the map information storage medium 5 is displayed on the screen of the display device 7, and 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 every moment in accordance with the preset map scale ratio, and the calculation result is sequentially sent to the traveling locus storage device 4 to update the stored contents. As it goes, the stored contents are constantly read and sent to the display device 7.

Thereby, on the display device 7, for example, as shown in FIG. 2, a display mark M1, which indicates the current position of the moving body, is displayed on the map displayed on the screen, and the traveling direction of the moving body at the current position is shown. The display mark M2 and the display mark M3 of the traveling locus from the starting point ST to the current position are simulated and displayed following the traveling state of the moving body.

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

Therefore, in such a current position display device for a moving body, as shown in FIG. 3, the current position and the traveling locus gradually deviate from the road on the map as the traveling of the moving body progresses due to the accumulated error described above. In the end, it becomes impossible to judge where on the map the vehicle is currently traveling.

In such a current position display device for a moving body, in the signal processing device 3, when the current position of the moving body and the traveling locus up to that point deviate from the road on the map, as described below, the vicinity thereof Matches the pattern of each road with the pattern of the traveling path of the moving body, considers the road with the matching pattern as the currently running road, and matches the traveling path on the road to move the moving body. The present position and the display position of the traveling locus are corrected.

At that time, when matching the pattern of the traveling locus with the pattern of the road, for example, the traveling locus of the moving body such as a road along the traveling locus of the moving body or a road within a certain distance range from the current position of the moving body, or Roads that have a certain correlation with the current position are extracted as road candidates for matching to reduce the burden of matching processing.

A specific example of extracting the candidate road will be described below.

First, the estimated current position of the moving body is set on the road on which the vehicle is currently traveling and on all roads branching from the road according to the constant traveling distance of the moving body.

At this time, as shown in FIG. 4 (a), if there is no branch road within a certain distance L from the set point of the previous estimated current position x ', the road is currently running and the moving body is running. Therefore, the estimated current position x is selected at a position advanced by the certain distance L. Further, as shown in FIG. 4 (b), if there are branch roads within the certain distance L, the estimated current positions x1, x2, x3 are set to all of the branch roads, respectively. Where 1+
There is a relationship of l2 = 1 + l3 = 1 + l4 = L.

It should be noted that the setting of the estimated current position is performed by the moving body at a certain distance
Every time it is detected that the vehicle has traveled, it is automatically performed under the control of the signal processing device 3 according to the position data of the road on the map displayed on the screen of the display device 7 at that time. The estimated current position may be set independently of the travel distance of the moving body, and the estimated current position may be sequentially set every time a predetermined time elapses as the moving body travels. It is also conceivable to change the set interval of the estimated current position according to the traveling condition of the mobile body. Each road is segmented into lines, and position data on the XY coordinates of each line segment is stored in the map information storage medium 5.

Next, check whether the distance between the estimated current position set as described above and the current position of the moving body calculated and displayed off the road is within a predetermined allowable range. A determination is made and an estimated current position within that range is selected, and only roads where the selected estimated current position exists are candidates for matching.

Now, for example, in the relationship of FIG. 5, the estimated current position x (x
1, x2, x3) and the current position P is D (D1, D2, D3)
In such a case, the estimated current position that satisfies the following equation D ≦ αL + M (1) is selected.

Here, M is a preset allowable range, for example, 50
It is set to about m. α is a coefficient relating to position accuracy when the traveling distance of the moving body is used as a parameter, and is, for example, 5
It is set to about%. Further, L is set to about 100 m.

At that time, it is possible to select an estimated current position set on a road having a direction within a certain allowable angular difference with respect to the traveling direction of the current position P of the moving body. .

Then, in the relationship of FIG. 5, if the value of M is set to be relatively small, for example, only x2 is selected as the estimated current position satisfying the condition of the equation (1), and the estimated current position x2 exists. The roads to be set are candidate roads to be subjected to the matching process.

Therefore, even if there are many roads near the current position deviating from the road, it is possible to select the minimum number of road candidates that have a high probability of being targeted for the matching process. The burden of matching processing is effectively reduced.

Further, when matching the pattern of the traveling path of the moving body and the pattern of the candidate road, if the matching process is sequentially performed every time the moving body travels a certain distance and the estimated current position is set, the processing load is large. Therefore, it is considered that the change in the shape of the traveling locus has a great feature when the direction variation of the traveling locus of the moving body is constantly monitored and the integrated value of the direction variation becomes larger than a certain value. At that time, the matching process according to the pattern of the traveling locus of the moving body during the integration period until then is executed at one time.

That is, as shown in FIG. 6, the angle wi (i = 0,1,2, i) between the X-axis of the travel locus at each point a, b, c, d, ... 3, ...), and the integrated value W of the direction change amount is sequentially calculated according to the following equation.

When the calculated total amount W of directional changes is equal to or greater than a preset value, traveling from the current position P of the moving body at that time to a start point a (which becomes the previous matching processing point) The locus is extracted as the target of this matching process.

Therefore, if the matching with the road is performed according to the traveling locus of the moving body in which the extracted pattern has a large feature, the number of matching processes is reduced as a whole, and the accuracy of the pattern is high according to the feature of the pattern. It becomes possible to perform efficient matching processing.

At this time, as the road pattern to be matched, as shown in FIG. 7, for example, as shown in FIG. 7, the estimated current position x selected according to the current position P of the moving body is set as the head and the previous matching processing point is set. The pattern of the road that cuts the set points of the past estimated current positions x'up to S is cut out.

When cutting out a road pattern in which a plurality of such estimated current positions are set so that the matching process is performed at one time, select each estimated current position that satisfies the relationship of equation (1) as described above. At each point of
Since the distance between the current position of the moving body and the estimated current position set on the road at that time gradually increases as the traveling of the moving body progresses, as the traveling of the moving body progresses (1 It is necessary to increase the value of M in the equation).

In the case of matching the extracted traveling locus pattern of the moving body with the pattern of the candidate road cut out as described above, for example, the traveling locus LP pattern as shown in FIG. Is approximated to a polygonal line by an equal length line segment, and the pattern of the candidate road RP is also approximated to a polygonal line shape by an equal length line segment as shown in FIG. Matching is performed using the vector sequence of each line segment.

By matching the traveling locus of the moving body and the road on the map with the respective polygonal-line-approximated patterns under the same conditions, the direction and position of each corresponding line segment can be easily compared. As a result, the matching process can be accurately and easily performed.

A specific matching process is performed as follows.

First, the position correlation between the running trajectory pattern and the candidate road pattern, which are approximated by polygonal lines by equal length line segments, is obtained. At that time, after rotating the traveling locus pattern in a predetermined manner so as to match the directionality of the road pattern, the distances between the head points of the corresponding line segments of the traveling locus pattern and the road pattern are integrated. It is a correlation of position.

That is, as the first step, the vector sequence approximated to the broken line of the traveling locus is And the vector sequence approximated by the polygonal line of the candidate road (| S1 | = | s2 | = ... = | sn | = | r1 | = | r2 | = ... =
| rn |) and the rotation angle θ of the vector sequence of the traveling locus is calculated according to the following equation.

Here, ω (i) is a weighting function.

As the second step, the trajectory vector sequence is rotated according to the rotation angle θ using the following equation.

By performing the rotation processing of the vector sequence of the traveling locus, the direction detection error can be corrected as a result.

As a third step, the correlation value f of the position is obtained according to the following equation in accordance with the vector sequence of the traveling locus and the vector sequence of the road that have been subjected to the rotation processing.

Next, taking into account the distance detection error in obtaining the current position P of the moving body, the head position x of the candidate road is taken into consideration.
With a vector sequence of roads extended by a certain distance + δ (several tens of meters) according to the road pattern, and with a vector sequence of roads shortened at the beginning position of the candidate road by a certain distance -δ according to the road pattern, the same as above. The correlation value f of the position with the vector sequence of the locus is obtained.

Finally, the smallest one of the obtained correlation values f is selected, and when the selected correlation value f is less than or equal to a reference value, it is determined that matching is achieved, and the result is shown in FIG. As shown, the travel locus LP is translated such that the current position P of the travel locus is at the head position (for example, the position of x + δ) of the matched road pattern, and then the travel locus is moved to the point P. Rotate by the angle θ to the center and fit on the matched road.

By performing such matching processing, the display position of the current position P of the moving body deviating from the road on the map and the display position of the traveling locus up to that position are corrected.

At that time, the roads cut out by dividing each position x + δ, x−δ from the estimated current position x on the candidate road by a fixed distance δ into a large number and dividing each position into the head position. If the correlation value f with each traveling locus pattern is obtained based on the pattern, and if the smallest correlation value f among them is equal to or less than the reference value, it is determined that matching has been achieved, the matching accuracy will be improved. You will be able to raise it.

According to the present invention, in the present invention, the map information storage medium 5 in the configuration of FIG. 1 stores the map information of the main road map and the detailed road map of the same area separately, and performs signal processing. Under the control of the device 3, the map information of the main road map or the detailed road map is selectively read according to the traveling condition of the mobile body, and the matching process is performed according to the read map information. It is characterized by that.

Specific means for performing selective switching between the main road map and the detailed road map according to the traveling state of the mobile body will be described below.

Now, for example, as shown in FIG.
And a detailed road map B that overlaps a part of the area, and switches to the detailed road map B when it is detected that the current position of the moving body enters the area of the detailed road map B, Further, when it is detected that the current position of the moving body is out of the area of the detailed road map B, it is switched to the main road map A.

At that time, in order that the mobile body does not frequently switch between the main road map A and the detailed road map B by moving in and out of the boundary portion of the detailed road map B,
A predetermined boundary area Z is set around the inside of the detailed road map B, and when it is detected that the current position of the moving body exceeds the boundary area Z and enters the area of the detailed road map B, the first time. The main road map A is switched to the detailed road map B.

Further, at that time, instead of setting the boundary area, when it is detected that the vehicle has traveled a predetermined distance after the current position of the moving body enters the area of the detailed road map B, it may be switched to the detailed road map B. Good.

Furthermore, it may be configured to switch to the detailed road map B when it is detected that a predetermined time has passed since the current position of the mobile body entered the area of the detailed road map B.

When such switching between the main road map A and the detailed road map B is performed, the map information storage medium 5 separately stores the map information as having no relation to each other. If the road map used for the matching process is switched when the mobile body travels inside and outside the area B, the matching process up to that point cannot be continued.

For example, when the current position of the moving body enters the area of the detailed road map B and is switched from the main road map A to the detailed road map B, the candidate road to be subjected to the matching process for the switched detailed road map B is selected. It is necessary to newly perform extraction, and the continuity of the matching process that has been performed using the main road map A up to that point will be lost.

Therefore, when importance is attached to the continuity of the matching process, it is desirable to prevent switching between the main road map A and the detailed road map B as much as possible.

Therefore, in the present invention, the signal processing device 3 employs the following road map switching means.

When entering the area of the detailed road map B, the matching process is continuously performed using the previous main road map A without immediately switching to the detailed road map B. When approaching a road that is not on the map A and the current position deviates from the road on the main road map A and the matching cannot be obtained, the detailed road map B is first switched at that point.

At that time, the determination that the current position of the moving body deviates from the road of the main road map A is, for example, in the relationship shown in FIG. When the distance D between them does not satisfy the relationship of the expression (1), the road is outside the main road map A. Alternatively, when the angle difference between the direction of the road where the estimated current position x is set and the traveling direction of the moving body at the current position P is outside the preset allowable range, the road is outside the main road map A.

Further, in the present invention, when the traveling speed of the moving body is taken into consideration, it is detected by the signal processing device 3 that the traveling speed detected by the speed sensor 1 is in a high traveling state equal to or higher than a preset threshold value. , Even if the moving body enters the area of the detailed road map B, without switching to the detailed road map B,
The matching process is continuously performed using the main road map A.

Further, when it is detected that the traveling speed of the moving body is lower than a preset threshold value, if the current position of the moving body falls within the area of the detailed road map B, the detailed road map B Switch to.

Further, in the present invention, in consideration of the matching processing time, in the signal processing device 3, when the moving body is in the area of the detailed road map B, when the matching processing time follows the traveling of the moving body, the detailed road map. When B is selected and the matching processing time does not follow the traveling of the mobile body, the main road map A is selected.

For example, at the time of executing the matching process using the detailed road map B, when a large number of candidate roads to be subjected to the matching process are selected and the processing load increases, the processing time of the matching at that time becomes long, and during that time. Since the traveling of the moving body progresses and the matching process cannot follow, the main road map A is switched to.

Further, when the roads in the detailed road map B are very complicated and the amount of information is large, it takes time to read the unitized map information as the traveling of the moving body progresses for the matching process, Since the reading of the map information cannot follow the traveling of the moving body, the map is switched to the main road map A.

As the detailed road map B, it is possible to prepare a plurality of maps in which the degree of detail is changed stepwise, and to switch the detailed road map B in multiple stages.

When switching to the detailed road map B, for example, as shown in FIG. 11, a flag mark of the shape shown at the intersection of the main roads is displayed.
It is also possible to stand M4 and display a predetermined intersection name in the flag mark M4.

In that case, the intersection name of the main road and the data of the flag mark M4 are previously stored together with the road data in the map information storage medium 5
Stored under the control of the signal processing device 3,
When the detailed road map B is displayed, the intersection name and the data of the flag mark M4 are read out, and the intersection name is displayed together with the flag mark M4 corresponding to the position of the predetermined intersection.

As described above, in the current position display device for a mobile body according to the present invention, the current position of the mobile body is always on the road while matching the pattern of the traveling locus of the mobile body and the pattern of the road on the map. When making a correction so that the matching process time is appropriately changed according to whether or not the matching processing time follows the traveling of the moving body, the selected main road map and detailed road map are selected and switched. It has an excellent advantage that the matching process using the road map can be performed optimally and accurately.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an embodiment of a current position display device for a mobile body according to the present invention, FIG. 2 is a diagram showing an example of a display screen in the same embodiment, and FIG. FIG. 4 is a diagram showing a state of being displayed off the road, and FIGS. 4 (a) and 4 (b) are diagrams showing a state in which an estimated current position is set on the road for each constant traveling distance of a moving body. ,
FIG. 5 is a diagram showing the relationship between the current position of a moving body that has deviated from the road and the estimated current position set on the road, and FIG. 6 is a diagram showing an example of the state of change in the traveling trajectory of the moving body.
FIG. 7 is a diagram showing a cut-out state of a candidate road pattern to be matched, and FIG. 8 (a) is a diagram showing a state in which a traveling locus pattern of a moving body is approximated by broken lines by equal-length line segments. FIG. 9B is a diagram showing a state in which a road pattern is approximated by broken lines by equal-length line segments, and FIG. 9 shows a state in which the current position and traveling locus of a moving body are aligned on the matched road. FIG. 10 is a diagram showing a detailed map overlapping a main road map and a part of the area, and FIG. 11 is a diagram showing an example of a display state of the detailed road map. 1 ... Speed sensor, 2 ... Direction sensor, 3 ... Signal processing device, 4 ... Running track storage device, 5 ... Map information storage medium, 6 ... Storage medium reproducing device, 7 ... Display device, 8 ......
Operating device, A: main road map, B: detailed road map

Continuation of front page (56) Reference JP-A-1-277714 (JP, A) JP-A-60-224021 (JP, A) JP-A-59-197817 (JP, A) JP-A-63-12912 (JP , A) Actual flat 1-104514 (JP, U) Actual 64-19117 (JP, U)

Claims (7)

[Claims] 1. A current position on a two-dimensional coordinate that changes with the traveling of a moving body is sequentially calculated by detecting a traveling distance and a traveling direction of the moving body, and map data is read out from a storage medium in advance. The current position of the moving body is updated and displayed on the screen on which the predetermined road map is displayed, and the traveling locus pattern and road of the moving body obtained by sequentially storing and holding the data of the current position in the memory. A current position display device for a mobile body that matches a road pattern on a map and adjusts the current position of the mobile body that has deviated from the road by matching the traveling locus on the matched road At
The main road map and the detailed road map in the same area are prepared as the road maps to be matched, and when the matching processing time follows the traveling of the moving body, the detailed road map is selected, and the matching processing time is selected. A current position display device for a mobile body, characterized in that a means for selecting a main road map is provided when the mobile body does not follow the traveling of the mobile body. 2. The main road map is selected when the traveling speed of the moving body is a certain speed or more, and the detailed road map is selected when the traveling speed of the moving body is less than the certain speed. The present position display device for a mobile body according to the above item 1. 3. A detailed road map for a part of the area of the main road map is prepared, switched to the detailed road map when the moving body enters the area, and switched to the detailed road map when the moving body leaves the area. The present position display device for a moving body according to the above-mentioned item 1 is characterized in that the means for switching to the present position is adopted. 4. A boundary area is set in the periphery of the area, and when the moving body crosses the boundary area and enters the area, the detailed road map is switched to. The present position display device of the moving body according to the description. 5. The current position display device for a moving body according to claim 3, wherein when the moving body travels a predetermined distance after entering the area, the detailed road map is switched. 6. The current position display device for a moving body according to claim 3, wherein the detailed road map is switched to when a predetermined time has elapsed after the moving body entered the area. 7. The method according to claim 3, wherein when a main road map is selected and the current position of the moving body deviates from the road on the map and the matching cannot be obtained, the detailed road map is switched. The present position display device of the moving body according to the description.