JP4136071B2 - Current position calculation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for calculating a current position in a navigation device or the like mounted on an automobile.
[0002]
[Prior art]
For example, in a navigation device mounted on an automobile, the current position of the vehicle is calculated by a technique called map matching.
[0003]
In this map matching technique, for example, the current position is calculated as follows.
[0004]
That is, first, the relative displacement of the vehicle with respect to the previously calculated current position is obtained from the travel distance and travel direction obtained using a vehicle speed sensor, a direction sensor, and the like. And this provisional present position is calculated | required by adding this to the present position calculated last time. Then, the point on the road that most closely matches the temporary current position and the current driving direction is obtained in consideration of the distance between the point on the road and the temporary current position, the direction of the road, and the like. The current position of
[0005]
By the way, for example, when a gyro device or the like is used as an azimuth sensor, only the displacement of the azimuth is obtained. Therefore, if this is integrated and used as the running azimuth, the measurement error of the azimuth sensor is accumulated, and the true traveling azimuth is obtained. The deviation with respect to the traveling direction increases with time. In addition, when a sensor that measures displacement in other directions is used as the direction sensor, since the obtained traveling direction includes an error, a direction greatly deviating from the true traveling direction is obtained as the measured direction. There is. In such a case, the current position cannot be calculated correctly depending on the map matching technique.
[0006]
Therefore, conventionally, in order to correct such an error in the traveling direction, the traveling direction at that time is corrected to the direction of the road where the current position calculated by map matching is located.
[0007]
In addition, in order to correct the travel direction error, a GPS (Global Positioning System) receiver is used to correct the travel direction error. In other words, the travel direction obtained from the direction sensor is compared with the travel direction obtained from the GPS receiver, and if the difference exceeds a certain value, the travel direction obtained from the GPS receiver is The running direction of was corrected. Considering that the accuracy of the moving direction obtained from the GPS receiver deteriorates as the traveling speed of the vehicle decreases, such correction is not performed when the traveling speed of the vehicle is below a certain value. Control was done.
[0008]
[Problems to be solved by the invention]
According to the conventional technique for correcting the traveling direction at that time to the moving direction obtained from the GPS receiver, the following problem occurs because the correction is not performed when the traveling speed of the vehicle is below a certain value. Has occurred.
[0009]
That is, for example, consider a case where the road is congested when traveling back to the road after traveling in a plaza or a multilevel parking lot.
[0010]
Here, an incorrect current position has been calculated on the surrounding road due to complicated driving in a plaza or multistory parking lot, or because map matching cannot be applied to the inside of a plaza or multistory parking lot. As a result, if the traveling direction is out of order, and the vehicle can travel only at a low speed due to traffic congestion even if it travels back on the road, the traveling direction cannot be corrected using the traveling direction obtained from the GPS receiver. For this reason, the correct current position cannot be calculated by map matching, and the subsequent calculation of the current position will continue to be adversely affected.
[0011]
Therefore, the present invention can determine whether or not the traveling azimuth is larger than the error in the moving azimuth obtained from the receiver, regardless of the moving speed. It is an object of the present invention to provide a current position calculation device capable of correcting a traveling direction to a moving direction obtained from a receiver having a small value.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides, for example, a current position calculation device that calculates a current position of a mobile object,
Means for storing road map data representing a road map;
Means for determining the current traveling direction of the moving body based on the traveling direction of the moving body obtained last time;
Means for determining the moving speed and moving distance of the moving body;
Referring to the road map data, the position on the road that most closely matches the current position calculated last time plus the displacement of the moving object obtained from the travel direction and distance of the moving object since the previous current position calculation is Means for calculating as a position;
A receiver for obtaining a moving direction of a moving object using a positioning system using a satellite;
Means for correcting the traveling direction to the traveling direction only when the difference between the traveling direction and the traveling direction is greater than or equal to the nth threshold value in the nth range (where n is an integer equal to or greater than 2). And
The k-th range of movement speeds (where k is an integer between 2 and n) includes only movement speeds that are smaller than the movement speeds included in the k-th range of movement speeds, and the k-th threshold is Provided is a current position calculating device characterized by being a value larger than a threshold value of k-1.
[0013]
According to such a current position calculation device, when the moving speed is low, the accuracy of the moving direction obtained from a receiver such as a GPS receiver is considered to be low, and the vehicle travels more than when the moving speed is high. Only when the difference between the azimuth and the moving azimuth is large, the traveling azimuth is adjusted to the moving azimuth. As a result, even if the moving speed is low and the accuracy of the moving direction obtained from the receiver is low by setting the range and threshold value of the moving speed appropriately, for example, empirically obtained values, the traveling direction is more than a certain degree. It is possible to determine whether or not there is a large error, and when the error is more than a certain degree, the traveling direction can be corrected to a moving direction obtained from a receiver having a smaller error.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a current position calculation device according to the present invention will be described taking application to an in-vehicle navigation device as an example.
[0015]
FIG. 1 shows a configuration of a navigation device according to the present embodiment.
[0016]
In the figure, 1 is a processing unit composed of a microprocessor and a memory, 2 is a display device, 3 is a drive unit responsible for accessing a storage medium such as a CD-ROM storing map data, and 4 is a user instruction. An input device for receiving input, 5 is a sensor device including a vehicle speed sensor, a direction sensor, and the like, and 6 is a GPS receiver.
[0017]
Next, FIG. 2 shows map data recorded on a storage medium such as a CD-ROM attached to the drive device 3.
[0018]
Here, map data recorded on a storage medium such as a CD-ROM mounted on the drive device 3 will be described.
[0019]
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 road data 21 is composed of road information 22 and link information 23.
[0020]
The road information 22 includes a road number 26 that uniquely represents the road, a road name 24 that represents the name of the road, a road type 27 that represents the type of the road (toll road, national road, prefectural road), and other road information. Other attributes 25 representing information are included.
[0021]
The link information 23 includes link data 28 representing link information provided for each link constituting the road. Here, the link is a straight line that approximates the shape position of the road as a set.
[0022]
The link data 28 describes a link number 29 that uniquely represents a link and a cost 30 of the link.
[0023]
The link data 28 includes, for each of the two nodes at the two ends, a node number 32 uniquely indicating the node, a node coordinate 35 indicating the position of the node, and all of the nodes connected via the link. The adjacent node number list 34 is a list of node numbers of the nodes. Here, the links are always connected at the nodes. For example, in 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 node numbers of the four nodes at the other end of the four links connected to the own node are described in the adjacent node number list 34 of the node provided at the center.
[0024]
In such a configuration, the processing device 1 repeats the process of calculating the current travel direction by adding the travel direction displacement of the vehicle input from the direction sensor of the sensor device 5 to the travel direction obtained last time. The processing device 1 repeats the process of calculating the travel distance of the vehicle by integrating the vehicle speed input from the vehicle speed sensor with time.
[0025]
The processing device 1 adds the current relative displacement from the previously calculated current position obtained from the calculated travel direction and travel distance history to the current position calculated last time for every 2 m travel, thereby Repeat the process of finding the position.
[0026]
Then, the processing device refers to the map data around the temporary current position for every fixed distance traveling (for example, every 2 m), and on the link that most closely matches the temporary current position and the current traveling direction by map matching processing. The point 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 position. At this time, the traveling direction is corrected to the direction of the road where the current position is located.
[0027]
Further, the processing device 1 controls the drive device 3 based on the calculated current position, the traveling direction of the vehicle, and the content specified by the user via the input device 5 to read out the map data, A map to be displayed is displayed on the display device 2. At this time, a mark representing the current position and traveling direction of the vehicle is superimposed on the map and displayed.
[0028]
Hereinafter, in this embodiment, the traveling direction correction process using the GPS receiver performed by the processing device 1 will be described.
[0029]
FIG. 3 shows a procedure of traveling direction correction processing using a GPS receiver.
[0030]
This process is executed every certain period or every certain distance (for example, 20 m).
[0031]
As shown in the figure, in this process, the processing device 1 first obtains the traveling direction θc calculated at the present time (step 301), and then the moving direction obtained from the GPS receiver 6 using a GPS satellite. θg is acquired (step 302). Then, the absolute value θ of the difference between the traveling direction θc and the moving direction θg is obtained (step 302).
[0032]
Hereinafter, the magnitude relationship between the predetermined threshold values v1, v2, v3 and the current vehicle speed v, the absolute value θ of the difference between the traveling direction θc and the moving direction θg, and the predetermined threshold values θ1, θ2, It is determined whether or not to perform correction to match the traveling direction θc with the moving direction θg according to the magnitude relationship with θ3. However, the threshold values v1, v2, and v3 have a relationship of v1 <v2 <v3, and the threshold values θ1, θ2, and θ3 have a relationship of θ1>θ2> θ3.
[0033]
First, if the current vehicle speed v is not greater than the threshold value v1 (step 304), the process is terminated without correcting the traveling direction θc.
[0034]
Next, when the vehicle speed v is larger than the threshold value v1 (step 304) and not larger than the threshold value v2 (step 305), it is checked whether or not the absolute value θ of the difference is larger than the threshold value θ1 (step). 310). If the absolute value θ of the difference is larger than the threshold value θ1, correction is made to match the traveling direction θc with the moving direction θg (step 308), and if not, processing is performed without correcting the traveling direction θc. finish.
[0035]
Next, when the vehicle speed v is larger than the threshold values v1 and v2 (steps 304 and 305) and not larger than the threshold value v3 (step 306), whether or not the absolute value θ of the difference is larger than the threshold value θ2. (Step 309). If the absolute value θ of the difference is larger than the threshold value θ2, correction is performed to match the traveling direction θc with the moving direction θg (step 308), and if not, processing is performed without correcting the traveling direction θc. finish.
[0036]
Next, when the vehicle speed v is greater than the threshold values v1, v2, and v3 (steps 304, 305, and 306), it is checked whether or not the absolute value θ of the difference is greater than the threshold value θ3 (step 309). If the absolute value θ of the difference is larger than the threshold value θ3, correction is performed so that the traveling direction θc matches the moving direction θg (step 308). If not, the processing is performed without correcting the traveling direction θc. finish.
[0037]
As a result of the above processing, as shown in FIG. 4, when the vehicle speed is higher, even if the absolute value of the difference between the travel direction θc and the travel direction θg is relatively small, the travel direction is corrected to match the travel direction. However, when the vehicle speed is smaller, only when the absolute value of the difference between the traveling azimuth θc and the moving azimuth θg is relatively large, correction for adjusting the traveling azimuth to the moving azimuth is performed.
[0038]
That is, this embodiment considers that the accuracy of the moving direction obtained from the GPS receiver is low when the vehicle speed is low, and the case where the difference between the traveling direction and the moving direction is larger than when the vehicle speed is high. Only the traveling direction is corrected to match the moving direction. In this way, by setting the threshold values v1, v2, v3, θ1, θ2, and θ3 appropriately, for example, empirically obtained values, the vehicle speed can be reduced and the movement obtained from the GPS receiver. Even if the direction accuracy is low, it can be judged from the moving direction obtained from the GPS receiver whether or not the traveling direction is largely incorrect to some extent. Can correct the driving direction to the moving direction obtained from a GPS receiver with small errors. Accordingly, it is possible to further reduce errors in the traveling direction during low-speed traveling, and to reduce adverse effects on the subsequent calculation of the current position.
[0039]
The position embodiment of the present invention has been described above.
[0040]
In the above embodiment, the vehicle speed is divided into four ranges, and whether or not the travel direction is corrected is determined based on different criteria for each range. However, the vehicle speed is divided into an arbitrary number of ranges of 3 or more. Whether or not to correct the azimuth may be determined based on different criteria for each range. In this case as well, when the vehicle speed is relatively high, even if the absolute value of the difference between the travel direction θc and the travel direction θg is relatively small, the travel direction is corrected to match the travel direction, and the vehicle speed is compared. In other words, if the absolute value of the difference between the traveling azimuth θc and the moving azimuth θg is relatively large, each reference is set so that the correction for adjusting the traveling azimuth to the moving azimuth is performed. Alternatively, when the absolute value θ> F (v) of the difference between the travel direction θc and the travel direction θg is satisfied in the full vehicle speed range or the partial vehicle speed range, the travel direction is corrected to the travel direction, If it does not hold, the correction for adjusting the traveling direction to the moving direction may not be performed. However, F (v) is a function that gives a value that does not satisfy F (vl)> F (vs) when vl> vs in all v ranges, and vl> vs in at least some v ranges. Is a function that gives a value such that F (vl) <F (vs).
[0041]
The processing device 1 in the present embodiment may be an electronic computer having a CPU, a memory, and an appropriate OS. In this case, the CPU describes the procedure of each processing performed by the processing device 1. This is realized by executing the program. In this case, these programs may be supplied to the processing apparatus 1 via a storage medium such as a CD-ROM.
[0042]
【The invention's effect】
As described above, according to the present invention, it is possible to further reduce errors in the traveling direction during low-speed traveling, and to reduce adverse effects on subsequent calculation of the current position.
[Brief description of the drawings]
FIG. 1 is a block diagram showing 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.
FIG. 4 is a diagram showing criteria for determining whether or not travel direction correction is possible according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Display apparatus 3 Drive apparatus 4 Input apparatus 5 Sensor apparatus 6 GPS receiver

Claims (4)

A current position calculation device for calculating a current position of a moving object,
Means for storing road map data representing a road map;
Means for determining the current traveling direction of the moving body based on the traveling direction of the moving body obtained last time;
Means for determining the moving speed and moving distance of the moving body;
Referring to the road map data, the position on the road that most closely matches the current position calculated last time plus the displacement of the moving object obtained from the travel direction and distance of the moving object since the previous current position calculation is Means for calculating as a position;
A receiver for obtaining a moving direction of a moving object using a positioning system using a satellite;
The threshold value set so as to be smaller as the moving speed of the moving body is larger is compared with the absolute value of the difference between the current traveling direction and the moving direction, and the current traveling direction and the Means for performing a correction to replace the current traveling direction with the moving direction when the absolute value of the difference in moving direction is larger than the threshold value according to the moving speed of the moving body;
A current position calculation device characterized by comprising: A current position calculation device for calculating a current position of a moving object,
Means for storing road map data representing a road map;
Means for determining the current traveling direction C of the moving body based on the traveling direction of the moving body obtained last time;
Means for determining the moving speed V and moving distance of the moving body;
Referring to the road map data, the position on the road that most closely matches the current position calculated last time plus the displacement of the moving object obtained from the travel direction and distance of the moving object since the previous current position calculation is Means for calculating as a position;
A receiver for obtaining a moving direction G of a moving object using a positioning system using a satellite;
Determining whether or not a predetermined condition is satisfied, and when satisfying, a means for performing correction to replace the traveling direction C with the moving direction;
The predetermined condition is:
If the moving speed V is greater than or equal to the predetermined moving speed V1 and less than the predetermined moving speed V2 greater than the moving speed V1, the absolute value of the difference between the traveling direction C and the moving direction G is greater than a predetermined positive angle θ1. Big or
If the moving speed V is greater than or equal to the moving speed V2 and less than a predetermined moving speed V3 that is greater than the moving speed V2, the absolute value of the difference between the traveling direction C and the moving direction G is greater than the predetermined positive angle θ1. Greater than a small positive angle θ2, or
If the moving speed V is equal to or higher than the moving speed V3, any one of the absolute value of the difference between the traveling direction C and the moving direction G is larger than the positive angle θ3 smaller than the predetermined positive angle θ2. A current position calculation device characterized by satisfying: A method for calculating a current position of a moving object,
Obtaining the current traveling direction of the moving body based on the traveling direction of the moving body obtained last time;
Determining the moving speed and moving distance of the moving object;
Referring to the road map data, the position on the road that most closely matches the current position calculated last time plus the displacement of the moving object obtained from the travel direction and distance of the moving object since the previous current position calculation is Calculating as a position;
Obtaining a moving direction of the moving object using a positioning system using a satellite;
The threshold value set so as to be smaller as the moving speed of the moving body is larger is compared with the absolute value of the difference between the current traveling direction and the moving direction, and the current traveling direction and the Performing a correction to replace the current traveling direction with the moving direction when the absolute value of the difference in moving direction is greater than the threshold value according to the moving speed of the moving body;
A method characterized by comprising: A storage medium storing a program to be read and executed by an electronic computer,
The program is
Obtaining the current traveling direction of the moving body based on the traveling direction of the moving body obtained last time;
Determining the moving speed and moving distance of the moving object;
Refers to the road map data stored by the electronic computer, and is most consistent with the current position calculated last time plus the displacement of the mobile object obtained from the travel direction and travel distance of the mobile object after the previous current position calculation. Calculating the position on the road as the current position;
Obtaining a moving direction of the moving object using a positioning system using a satellite;
The threshold value set so as to be smaller as the moving speed of the moving body is larger is compared with the absolute value of the difference between the current traveling direction and the moving direction, and the current traveling direction and the A step of performing correction to replace the current traveling direction with the moving direction when the absolute value of the difference in moving direction is larger than the threshold value corresponding to the moving speed of the moving body. To implement,
A storage medium storing a program characterized by the above.

Images