JPH11325929A - Present position calculating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute correction of running azimuth with few errors in the case of passing a Y-shaped road to the branch direction. SOLUTION: Just after passing a Y-shaped road to a branch direction, possibility that a present position is calculated on a wrong road by map matching is considered, and a processing equipment 1 does not execute correction for making the running azimuth coincide with the road azimuth of a present position. In the case that the azimuth difference of two branch roads is small, correction for making the running azimuth coincide with the road azimuth of a present position is executed. By this equipment, adverse influence on the calculation of a present position can be reduced which is caused by subsequent map matching, when the Y-shaped road is passed in the branch direction, and the running azimuth deviates from a true running azimuth exceeding an allowable range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for calculating a current position in a navigation device mounted on an automobile or the like.

[0002]

2. Description of the Related Art For example, in a navigation device mounted on an automobile, a current position of a vehicle is calculated by a technique called map matching.

In this map matching technique, for example, the current position is calculated as follows.

That is, first, a relative displacement of the vehicle with respect to the current position calculated last time is obtained from a running distance and a running direction obtained by using a vehicle speed sensor, a direction sensor and the like. Then, by adding this to the current position calculated last time,
Find the temporary current position of this time. Then, a point on the road that most closely matches the provisional current position and the current driving direction is determined in consideration of the distance between the point on the road and the provisional current position, the direction of the road, and the like. And the current position.

When a gyro device or the like is used as a direction sensor, for example, only the displacement of the direction can be obtained. The deviation of the heading from the true running heading increases with time. Also, when a sensor that measures displacement in another direction is used as a direction sensor, the direction that is greatly deviated from the true direction may be determined as the measured direction because the calculated direction includes an error. There is. In such a case, the current position cannot be correctly calculated depending on the map matching technique.

Therefore, conventionally, in order to correct such an error in the traveling direction, when the current position is determined at a point on the road by map matching, the current direction is added to the direction of the road on which the current position is located. Correction of the running direction has been performed.

In the correction of the traveling azimuth, immediately after passing in the direction of branching off the Y-shaped road, the current position is incorrectly calculated at the point on the road of the other branch, not the branch entered by map matching. And often
Considering that correcting the running direction to the wrong road direction will adversely affect the subsequent calculation of the current position,
Immediately after passing in a branching direction, the traveling azimuth is not corrected until the vehicle travels a certain distance.

[0008]

Immediately after the vehicle has traveled in a direction branching off the Y-shaped road, the traveling direction is not corrected for the direction of the road on which the current position calculated by map matching is located until the vehicle travels for a certain distance. According to this,
Since the traveling azimuth is not corrected, the traveling azimuth that is out of the allowable traveling range from the true traveling azimuth may be used next time when the current position is calculated. For this reason, the current position may be calculated on the wrong road by map matching as the next current position.
In this case, the traveling azimuth is corrected to the erroneous road azimuth, which has an adverse effect on the subsequent calculation of the current position.

In view of the above, the present invention provides a method for determining the present position of a current position by map matching, which is caused by the fact that the traveling azimuth deviates from the true traveling azimuth beyond the permissible range when the vehicle travels in the direction branching off the Y-shaped road. It is an object to reduce an adverse effect on calculation.

[0010]

In order to achieve the above object,
The present invention is, for example, a current position calculating device that calculates a current position of a moving object, the means for storing road map data representing a road map, and the current position of the moving object based on the traveling direction of the moving object obtained last time. Means for determining the traveling direction of the vehicle, means for determining the travel distance of the moving object, and road map data,
Means for calculating, as the current position, a position on the road that most closely matches a position obtained by adding the displacement of the moving object obtained from the traveling direction and the moving distance of the moving object since the previous current position calculation to the previously calculated current position, Correction means for correcting the running direction at the time when the current position is calculated to match the direction of the road on which the calculated current position is located, and a predetermined distance and a moving object immediately after passing in the direction of branching the Y-shaped road. While traveling, if the azimuth difference between the two branched roads is not smaller than a predetermined value, the correction means does not perform the correction, and if the azimuth difference between the two branched roads is smaller than a predetermined value, the correction means And a means for performing the correction.

According to such a current position calculating device, Y
Immediately after passing through a junction, the traveling azimuth is corrected only when the azimuth difference of the branched road is smaller than the threshold value. Is not corrected. Here, by setting the threshold value to an appropriate small angle value, if the azimuth difference between the branched roads is small, for example, if the true current position of the two branched roads is located on one road, If the current position is calculated by mistake on the other road, the difference between the direction of the wrong road and the direction of the other road on which the true current position is located is small. Even if the measurement azimuth is corrected to the azimuth of the road, almost correct correction will be performed. Further, when the current position is calculated on the road on which the true current position is located, correct correction can be performed by correcting the traveling azimuth. Therefore, when the directional difference between the branched roads is small, it is possible to perform a substantially correct correction of the traveling azimuth without waiting for the vehicle to travel a fixed distance as in the related art. An adverse effect on the calculation can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present position calculating device according to the present invention will be described below with reference to an application to an in-vehicle navigation device.

FIG. 1 shows the configuration of a navigation device according to this embodiment.

In the figure, reference numeral 1 denotes a processing unit composed of a microprocessor and a memory, 2 denotes a display device, 3 denotes a drive device for accessing a storage medium such as a CD-ROM in which map data is stored, and 4 denotes a user. An input device 5 for receiving the input of the instruction is a sensor device including a vehicle speed sensor, a direction sensor, and the like.

Next, a CD-ROM mounted on the drive device 3
FIG. 2 shows map data recorded on a storage medium such as the like.

Here, the CD-R mounted on the drive device 3
The map data recorded on a storage medium such as an OM will be described.

The map data is prepared for each rectangular geographical area called a mesh. As shown in FIG. 2, the map data of each mesh is composed of road data 21 provided for each road.
And the link information 23.

The road information 22 includes a road number 26 uniquely indicating a road, a road name 24 indicating a road name, a road type 27 indicating a type of the road (a toll road, a national road, a prefectural road), and the like. Other attribute 25 representing the information of the road.

The link information 23 includes link data 28 provided for each link constituting the road and representing link information. Here, the link is a straight line that approximates the shape position of the road as a set.

The link data 28 describes a link number 29 uniquely indicating a link and a cost 30 of the link.

The link data 28 includes, for each of the two nodes at both ends, a node number 32 uniquely indicating the node, a node coordinate 35 indicating the position of the node, and a link via the node and the link. An adjacent node number list 34, which is a list of node numbers of all connected nodes, is included. Here, the connection between the links is always performed at the node. For example, at a crossroad, a node is provided at the center, and four links are connected to the node provided at the center. In this case, the adjacent node number list 34 of the node provided at the center describes the node numbers of the other four nodes of the four links connected to the own node.

In such a configuration, the processing device 1
The process of calculating the current running direction is repeated by adding the running direction displacement of the vehicle input from the direction sensor of the sensor device 5 to the previously obtained running direction. Further, the processing device 1 repeats the process of integrating the vehicle speed input from the vehicle speed sensor with time and calculating the traveling distance of the vehicle.

The processing unit 1 adds the current relative displacement from the previously calculated current position obtained from the history of the calculated running azimuth and running distance to the previously calculated current position every 2 m, thereby Is repeated.

The processing device refers to the map data around the temporary current position every time the vehicle travels a fixed distance (for example, every 2 m), and performs the map matching process to most closely match the temporary current position and the current traveling direction. A point on the link is determined in consideration of the distance between the point on the link and the temporary current position, the direction of the link, and the like, and this is set as the current current position.

Further, the processing device 1 reads the map data by controlling the drive device 3 based on the calculated current position, the heading of the vehicle, and the contents specified by the user via the input device 5. The map represented by the map data is displayed on the display device 2. At this time, a mark indicating the current position and the traveling direction of the vehicle is superimposed on the map and displayed on the map.

Hereinafter, the traveling azimuth correction processing performed by the processing device 1 in the present embodiment will be described.

FIG. 3 shows the procedure of the traveling azimuth correction process.

The traveling azimuth correction processing is executed every time the vehicle travels 20 m.

As shown in the figure, in this processing, the processing device 1 first determines whether the vehicle has passed the Y-junction from the last calculated current position and the current position calculated immediately before the current position. , It is determined whether one of the two links forming the V portion of the Y-shaped road has entered from the link forming I (step 301). Here, whether or not the Y-shaped road is different is determined based on, for example, whether or not the azimuth difference between the two links forming the V portion is 30 degrees or less.

If the vehicle is passing in the direction of branching off the Y-shaped road, 500 m is set as the monitoring distance L (step 302).

Next, it is checked whether the monitoring distance L is larger than 0 (step 303). If it is smaller than 0, the monitoring distance L is set to 0 (step 308), the traveling direction is corrected to the direction of the link where the current position is located (step 309), and the process is terminated.

On the other hand, if the monitoring distance L is greater than 0, the azimuth difference θdiff between the two roads forming the V portion of the Y-shaped road that has passed is obtained (step 304). Here, the azimuth difference θdiff of the road to be determined is the difference between the azimuth of the link at which the current position at that time is located and the azimuth of the link that most closely matches the provisional current position or the traveling azimuth among the links of the other road. Here, the link on the other road used for calculating the heading difference is a link on which the current position can be obtained by map matching when only the other road is subjected to map matching. In other words, if the current position is calculated on a link of an erroneous road by map matching, it is a link of the other road on which the true current position can be estimated. Actually, in the map matching, when calculating the current position, for a plurality of links around the temporary current position, the position on the link matching the temporary current position and the traveling direction and the degree of matching are obtained, and the degree of matching is the highest. The position on the large link is calculated as the current position. Therefore, the link of the other road to be used for calculating the azimuth difference can be determined using the degree of matching of each link of the other road obtained in the map matching process.

Then, it is determined whether or not the azimuth difference θdiff is equal to or smaller than a predetermined threshold value mdeg (for example, 5 degrees) (step 305).

If the azimuth difference θdiff is not equal to or less than mdeg, the moved distance 20 m is subtracted from the monitoring distance L (step 307), and the processing is terminated.

On the other hand, if the azimuth difference θdiff is less than mdeg,
The traveling direction is corrected to the direction of the link where the current position is located (step 306).

As a result of the above processing, when the vehicle passes through the Y-junction in the direction of branching, the azimuth difference θdiff between the two roads forming the V portion becomes the threshold while traveling 500 m thereafter.
If the angle is equal to or less than mdeg, at that time, the measured direction is corrected to the direction of the link where the current position is located. On the other hand, if the azimuth difference θdiff between the two roads forming the V portion is not less than the threshold value mdeg while traveling 500 m,
When the vehicle travels, the measured direction is corrected to the direction of the link where the current position is located.

That is, in this embodiment, immediately after passing through the Y-shaped road, the traveling azimuth is corrected only when the azimuth difference of the branched road is small. Do not correct the running direction until the vehicle has traveled a certain distance. Here, when the direction difference of the branched road is small,
Even if the true current position of the two branched roads is located on one road, even if the current position is incorrectly calculated on the other road by map matching, the direction of the incorrect road and the true Since the difference in azimuth from the other road on which the current position is located is small, even if the measurement azimuth is corrected to the wrong road azimuth, almost correct correction will be performed. Also, if the current position is calculated on the road where the true current position is located by map matching,
Correct correction can be performed by correcting the traveling azimuth.

Therefore, according to this embodiment, when the azimuth difference between the branched roads is small, it is possible to perform a substantially correct azimuth correction without waiting for the vehicle to travel a certain distance as in the related art. , The adverse effect on the calculation of the current position by the subsequent map matching can be reduced.

The embodiment of the present invention has been described above.

The processing apparatus 1 according to the present embodiment
The computer may be a computer having a CPU, a memory, and an appropriate OS. In this case, each of the processes performed by the processing device
Is realized by executing a program describing the procedure of each process. In this case, these programs may be supplied to the processing device 1 via a storage medium such as a CD-ROM.

[0041]

As described above, according to the present invention, when the vehicle travels in a direction branching off a Y-shaped road, the traveling direction deviates from the true traveling direction by more than an allowable range. An adverse effect on the calculation of the current position by map matching can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a navigation device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of map data according to the embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the navigation device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing device 2 Display device 3 Drive device 4 Input device 5 Sensor device

Claims (4)

[Claims] 1. A current position calculating device for calculating a current position of a moving object, comprising: means for storing road map data representing a road map; and a current position of the moving object based on a traveling direction of the moving object obtained last time. Means for determining the traveling azimuth, means for determining the traveling distance of the moving body, and the moving body which is obtained from the traveling azimuth and the moving distance of the moving body since the previous current position calculation at the current position calculated last time by referring to the road map data. Means for calculating, as the current position, the position on the road that most closely matches the position obtained by adding the displacement of the vehicle, and correcting the running direction at the time when the current position is calculated to the direction of the road on which the calculated current position is located. And a correction unit that performs a predetermined distance and immediately after passing through the Y-shaped road in a branching direction, while the moving body moves, when the azimuth difference between the two branched roads is not smaller than a predetermined value, correction Not done, the orientation difference between the two roads branch current position calculating device including a means for such to perform the correction in the correcting means is smaller than a predetermined value. 2. A current position calculating device for calculating a current position of a moving object, comprising: means for storing road map data representing a road map; and a current position of the moving object based on a traveling direction of the moving object obtained last time. Means for determining the traveling azimuth, means for determining the traveling distance of the moving body, and the moving body which is obtained from the traveling azimuth and the moving distance of the moving body since the previous current position calculation at the current position calculated last time by referring to the road map data. Means for calculating, as the current position, the position on the road that is most consistent with the temporary current position that is the position obtained by adding the displacement of the current position. Correction means for performing correction to match the azimuth of, after passing in the direction of branching the Y-shaped road, a predetermined distance, while the moving body moves, the direction of the road where the current position is located among the two roads branching, Branch If the difference between the direction of the road at the position that most closely matches the provisional current position on the road on which the current position is not located is smaller than a predetermined value, the correction unit performs the correction. A current position calculating device comprising: means for preventing the correction means from performing the correction. 3. A method for calculating a current position of a moving object on a device for storing road map data representing a road map, wherein the current driving direction of the moving object is determined based on a previously obtained traveling direction of the moving object. Determining the moving distance of the moving body, and calculating the moving distance of the moving body by referring to the road map data and calculating the displacement of the moving body obtained from the traveling direction and the moving distance of the moving body since the previous current position calculation with reference to the road map data. Calculating the position on the road that most closely matches the added position as the current position; and after passing through the Y-junction in the direction in which it branches, the direction of the two roads that branch while the moving body moves a predetermined distance. If the difference is smaller than the predetermined value, the traveling direction at the time when the current position is calculated is corrected to match the direction of the road on which the calculated current position is located. The step of not performing the correction when the current position is not smaller than the predetermined direction, and the traveling azimuth at the time when the current position is calculated after the predetermined distance and the moving body have moved after passing in the direction of branching the Y-shaped road, is calculated. Making a correction to match the direction of the road on which the current position is located. 4. A storage medium storing a program read and executed by an electronic computer, the program comprising: obtaining a current traveling direction of a moving object based on a traveling direction of a moving object obtained last time; Obtaining the moving distance of the moving body, and referring to the road map data, to the position obtained by adding the displacement of the moving body obtained from the traveling direction and the moving distance of the moving body since the last calculation of the current position to the current position calculated last time. Calculating the position on the road that matches the most as the current position; and after passing through the Y-junction in the branching direction, while moving the mobile unit for a predetermined distance, the azimuth difference between the two roads that branch is a predetermined value. If it is smaller, the traveling azimuth at the time when the current position is calculated is corrected to match the azimuth of the road where the calculated current position is located. The step of not performing the correction if not smaller, the traveling azimuth at the time when the current position is calculated after the moving body has moved by the predetermined distance after passing through the Y-junction in the branching direction, and Making the computer execute a correction to match the direction of the road on which the position is located.