JP3613593B2 - Vehicle position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle position detection apparatus that lays a magnetic marker on a road and identifies the position of the vehicle.
[0002]
[Prior art]
Conventionally, as this type of vehicle position detecting device, for example, there is JP-A-2001-28095. This is because a magnetic marker is embedded at a predetermined interval on the road, and a magnetic sensor for detecting the magnetic marker, and an array pattern (M-sequence pattern) of magnetic poles of the magnetic marker are read from the detection signal of the magnetic sensor, and the position of the vehicle The vehicle is provided with processing means for specifying the above.
[0003]
The M sequence (maximum length sequence) is a kind of pseudo-random code (PN (Pseudo Noise) code), which is represented by a basic formula: M = 2 ^ n−1, and the meaning thereof is M. By optimizing the polarity of the magnets (magnetic markers), it is a series that makes it possible to determine which position of the M array of magnet rows is possible by determining the n marker polarities.
[0004]
By the way, in the above-described apparatus, the position can be specified only by one type of predetermined M sequence. As a problem of the M series, information in one series cannot be changed. Therefore, when a malicious third party places another magnetic marker between the magnetic markers, there is a problem that the position information cannot be restored until n magnetic markers are read again.
[0005]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a vehicle position detection device that can solve the conventional problems as described above and can specify a vehicle position from several types of M-sequence information.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is directed to a magnetic marker arranged according to an M-sequence PN code in a vehicle traveling direction on a road and laid by determining a direction of a magnetic pole, and traveling on a road. In a vehicle position detection device that includes a magnetic sensor that is mounted on a vehicle and detects a magnetic pole of the magnetic marker, and that identifies a vehicle position from an array of magnetic poles of the magnetic marker detected by the magnetic sensor, the installation interval of the magnetic marker is The vehicle position is specified by discriminating M sequence information to be referred to from several different types of M sequence information.
[0007]
A second aspect of the present invention is the first aspect according to the first aspect, further comprising a sensor for detecting a wheel pulse or a distance traveled by the vehicle, and M-sequence information in which a magnetic marker laying interval is arranged at a first interval. , The second database having M series information in which the magnetic marker laying interval is arranged at the second interval, the information detected by the sensor and the information of the magnetic marker laying interval detected by the magnetic sensor When the magnetic marker laying interval is the first interval, the M sequence information in the first database is used, and when it is the second interval, the M sequence information in the second database is used. And an arithmetic unit that discriminates the series information and switches the database.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram, and magnetic markers 1 arranged according to an M-sequence PN code are laid at a predetermined interval L on a road. On the other hand, the vehicle 2 includes a sensor 3 for detecting wheel pulses or a distance traveled by the vehicle, a magnetic sensor 4 for detecting the magnetic force and polarity (magnetic pole) of the magnetic marker 1, the interval between the detected magnetic markers 1, and information from various sensors. Arithmetic device 5 for identifying the interval between magnetic markers 1, first database 6 having M-sequence information arranged with L1 (for example, 4 m) intervals between magnetic markers 1, and L2 (for example, 3 m) between magnetic markers 1 ) A second database 7 having M-sequence information arranged at intervals is arranged. The contents of the first database 6 and the second database 7 are code information based on the M series, for example, traveling vehicle position information of the host vehicle.
[0009]
The first database 6 stores M-sequence information when the interval between the magnetic markers 1 is L1, and the second database 7 stores M-sequence information when the interval between the magnetic markers 1 is L2. Yes. The arithmetic unit 5 calculates the interval between the magnetic markers 1 from various information, and switches between the first and second databases 6 and 7 to be referred to.
[0010]
The operation will be described below. The vehicle 2 is traveling at a speed V [km / h]. It is assumed that the traveling distance is confirmed from the speed and wheel pulse during traveling. The magnetic sensor 4 attached to the vehicle 2 detects the magnetic marker 1 laid on the road and sends the information to the arithmetic unit 5. The arithmetic unit 5 determines a database to be referred to by using the speed and the vehicle pulse for the interval between the magnetic markers 1. When the interval is L1, the M sequence information of the first database 6 is used. Similarly, when the interval is L2, the position is specified using the M sequence information of the second database 7.
[0011]
A method of calculating the interval between the magnetic markers 1 will be described with reference to FIG. The magnetic marker 4 laid on the road is detected by the magnetic sensor 4. The wheel pulses are counted until the magnetic sensor 1 next detects the magnetic marker (the wheel pulse interval is assumed to be known in advance). And the space | interval L of the magnetic marker 1 is calculated from the count number of this wheel pulse.
[0012]
FIG. 3 shows an application example in the case of specific use. This is an application to the determination before the intersection (by adding the M-sequence code string for the intersection before) or the determination of the curve entrance as shown (by adding the M-sequence code string for the curve entrance). Normal M-sequence information is arranged at intervals of L1. Therefore, the vehicle normally travels along the information from the first database 6. In front of the curve, there is M-sequence information for curve entrances arranged at intervals of L2, and the information in the second database 7 is referenced to confirm that it is a curve entrance.
[0013]
As described above, in the case of laying in the M series as in the conventional magnetic marker, it is read continuously as one code length, and a malicious third party put another magnetic marker between the magnetic markers. However, in this embodiment, the M-sequence information of the magnetic marker row arranged in L1 and the magnetic marker row arranged in L2 is separated. Therefore, there is no such false detection.
[0014]
In the above embodiment, two types of L1 and L2 are shown as the magnetic marker laying intervals. However, three or more types of L3, L4...
[0015]
【The invention's effect】
As described above, according to the first and second aspects of the invention, the vehicle position can be specified from several types of M-sequence information by changing the laying interval of the magnetic markers laid on the road.
[Brief description of the drawings]
FIG. 1 is a schematic diagram according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining a magnetic marker interval calculation method;
FIG. 3 is a diagram illustrating an application example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic marker 2 Vehicle 3 Sensor 4 Magnetic sensor 5 Arithmetic device 6 1st database 7 2nd database

Claims (2)

A magnetic marker arranged in accordance with an M-sequence PN code in the vehicle traveling direction on the road and laid by determining the direction of the magnetic pole, and a magnetic sensor mounted on a vehicle traveling on the road and detecting the magnetic pole of the magnetic marker In a vehicle position detection device for identifying a vehicle position from an array of magnetic poles of the magnetic marker detected by the magnetic sensor,
A vehicle position detection device characterized by identifying M-sequence information to be referred to from several types of M-sequence information having different magnetic marker laying intervals to identify a vehicle position. A sensor for detecting a wheel pulse or a distance traveled by the vehicle, a first database having M-sequence information in which the magnetic marker laying interval is arranged at the first interval, and the magnetic marker laying interval being the second interval When the magnetic marker laying interval is the first interval from the second database having the M-sequence information arranged in the above and the information detected by the sensor and the magnetic marker laying interval information detected by the magnetic sensor. Uses the M-sequence information of the first database and, if the interval is the second interval, uses the M-sequence information of the second database to determine the M-sequence information to be referenced and switches the database. The vehicle position detecting device according to claim 1, comprising:

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