JP2001028095A - Road traffic system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately obtain the positional information of a vehicle by reading the array pattern of the magnetic pole of a magnetic marker from the detection signal of a magnetic sensor and specifying the vehicle position. SOLUTION: A magnetic sensor 35 detects magnetism while a vehicle travels, outputs its detection signal to a waveform shaping circuit 36, and the circuit 36 shifts a clock signal of 0 or 1 on the basis of the detection signal to output the clock signal to a shift register 37 and acquires a binary code corresponding to an M sequence pattern during traveling. Then, the binary code information is collated with binary code information stored in a road map memory 20, a processing circuit 15 acquires the vehicle positional information of a self- vehicle and displays the vehicle positional information on a vehicle map displaying means 21. Thus, it is possible to accurately specify the vehicle position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road traffic system in which a magnetic marker is embedded in a road to specify the position of a vehicle.

[0002]

2. Description of the Related Art In recent years, traffic problems such as traffic accidents and traffic congestion are becoming more serious with the increase in vehicles, and a road traffic system has been proposed in order to solve these traffic accidents and traffic congestion. .

[0003]

In such a road traffic system, there is a method of acquiring position information of a vehicle using a GPS system, but it has been difficult to accurately acquire the position.

[0004] It is an object of the present invention to provide a road traffic system capable of accurately obtaining vehicle position information.

[0005]

According to one aspect of the present invention, there is provided a road traffic system for specifying a position of a vehicle traveling on a road, wherein the road is separated from the road by a predetermined distance. A marker is embedded in the vehicle, and a magnetic sensor for detecting the magnetic marker, and processing means for reading an array pattern of magnetic poles of the magnetic marker from a detection signal of the magnetic sensor and specifying a position of the vehicle are provided in the vehicle. Features.

According to a second aspect of the present invention, one magnetic pole of the magnetic marker is directed to a road surface, and the position of the vehicle is specified by an arrangement pattern of the magnetic poles directed to the road surface.

The invention according to claim 3 is characterized in that the arrangement pattern of the magnetic poles is an M-sequence pattern.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of a road traffic system based on two-way communication between vehicles to which a road traffic system according to the present invention is applied. 1 shows a vehicle traveling on a highway 1. Each of the vehicles 2 to 14 is running from left to right. Vehicles 2 to 4, 8 to 10, and 12 to 14 are mounted vehicles on which the inter-vehicle bidirectional transmission / reception device is mounted, vehicles 5 to 7, 1
Reference numeral 1 denotes a non-mounted vehicle on which the inter-vehicle two-way transmission / reception device is not mounted, and it is assumed that the vehicle 1 is traveling on the highway 1 in a state where the mounted vehicle and the non-mounted vehicle are mixed.

Each vehicle is equipped with a traffic system circuit shown in FIG. The traffic system circuit includes a processing circuit (processing means) 15 for performing a process required for the road traffic system by the two-way communication between the vehicles, and a front seat information (vehicle information) of the own vehicle from the own vehicle to each mounted vehicle. Transmitting means 16 for wirelessly transmitting position information, vehicle speed information, brake information), a response signal generating circuit 16 ', receiving means 17 for receiving front seat information transmitted by the transmitting means 16, Distance measuring means 18 for measuring the distance and direction, vehicle position detecting means 19 for detecting the vehicle position of the own vehicle, road map memory 20,
The vehicle roughly comprises a vehicle map display means 21 for displaying the position of each vehicle centering on the own vehicle.

The transmission means 16 comprises a carrier circuit 22, a PN code generation circuit 23, a modulation circuit 24, and a transmission circuit 25. The receiving means 17 includes a receiving circuit 26, a correlation detecting circuit 27
(27a-27g), demodulation circuit 28 (28a-28g)
Consists of The distance measuring means 18 is a PN code modulation circuit 2
9, a single pulse generating circuit 30, a count pulse generating circuit 31, a counting circuit 32, a reflected wave receiving circuit 33, and a correlation detecting circuit 34. The vehicle position detecting means 19 includes a magnetic sensor 35, a waveform shaping circuit 36 for both amplification and a shift register 37.

On the highway 1, first beacons 38 and 39 are provided at a predetermined interval L1 along the vehicle traveling direction, and at predetermined intervals L2 in the vehicle traveling direction with respect to the first beacons 38 and 39. Second beacons 40 and 41 are provided. The interval L1 is, for example, 1 km, and the interval L2 is, for example, 100 m.

As shown in FIG. 3, the first beacons 38 and 39 include a PN code assignment generating circuit 42 and a vehicle recognizing means 4.
3, a response signal detection circuit 44 and a transmission / reception circuit 45 are provided.

Here, a PN code assignment generating circuit 42
The short code length is used for the PN code generated from the PN code. In the example shown in FIG. 1 as an example, bidirectional communication is possible between seven mounted vehicles, that is, vehicles having PN codes PN1 to PN7, respectively. Have been. When the code length L is increased (when the code length is long), the number of the correlation detection circuits 27 increases and the cost increases, and communication with a vehicle located far from the own vehicle is necessary for traveling of the own vehicle. It is because the nature is thin.

The PN code assignment generating circuit 42 updates the code of the M-sequence pattern every time the onboard vehicle passes, and transmits code assignment information from the transmitting / receiving circuit 45 to the onboard vehicle. A dedicated carrier is used for the code assignment information, and the receiving circuit 26 of the onboard vehicle receives the code assignment information. The processing circuit 15 decodes the communication code assigned to the own vehicle based on the code assignment information, and outputs the communication code to the PN code generation circuit 23. At the same time, a response signal transmission command is output to the response signal generation circuit 16 '. The response signal generation circuit 16 'transmits the response signal to the first beacon 38, 3
Output to 9

The PN code generation circuit 23 superimposes the front sheet information from the processing circuit 15 on the PN code given by the code assignment information and outputs the superposed PN code.
Modulates the carrier from the carrier circuit 22 with the output signal and outputs the modulated signal to the transmission circuit 25.
Broadcast (wirelessly transmit) the code-modulated front seat information of the own vehicle to another vehicle. That is, the transmission circuit 25 outputs a signal modulated with both the PN code and the front sheet information.

The receiving circuit 26 receives the front seat information broadcasted from another vehicle and detects it by the correlation detecting circuit 27. Correlation detection circuits 27a to 27g
Detects the correlation of the transmission information transmitted from each vehicle,
Output to each of the demodulation circuits 28a to 28g. Each demodulation circuit 28
a to 28g output demodulated signals to the processing circuit 15, which extracts at least vehicle position information of the mounted vehicle based on the PN code information and the front seat information,
The relative position of each mounted vehicle with respect to the own vehicle is calculated, and the relative position information of each mounted vehicle is output to the map display means 21. The map display means 21 displays the position of each mounted vehicle as a vehicle travel map.

FIG. 1 shows that on-board vehicles 2, 2
The PN codes assigned to 3, 8, 10, 12, and 13 are indicated by decimal numbers. The same PN code is assigned to the onboard vehicle 2 and the onboard vehicle 13.
If the inter-vehicle distance between the vehicle and the on-board vehicle 13 is sufficiently large, and if the range of the two-way communication is within 200 m before and after the vehicle, it is considered that no interference will occur.

The first beacons 38 and 39 indicate that the vehicle
Each time the vehicle passes through the beacons 38 and 39, the vehicle recognition means 43 recognizes the difference between the vehicle and the mounted vehicle and the non-mounted vehicle,
Further, the response signal detection circuit 44 detects whether the PN code is assigned to the mounted vehicle by receiving the response signal. Each time the first beacon 38 receives a response signal, it changes the PN code and transmits it to the running vehicle. Since there is no response signal from the non-equipped vehicle, the PN code is not changed, and therefore, the PN code is not assigned to the non-equipped vehicle. The distinction between on-board and off-board vehicles is
Since the vehicle is identified based on the presence or absence of the response signal, the non-equipped vehicle is equipped with a vehicle-to-vehicle two-way communication means, but some vehicles have a failure in the response signal generation circuit 16 '.

The first beacon 38 transmits the vehicle running information to the map creator 46 of the base station upon completion of the allocation, and allocates the PN code from the beginning to the following mounted vehicles. In FIG. 1, when the following vehicle 14 crosses the first beacon 38, the PN code “1” is assigned. The map creator 46 creates a vehicle travel map of the passing vehicles 3 to 13 based on the vehicle travel information from the first beacon 38 and transmits the vehicle travel map to the second beacons 40 and 41. The second beacons 40 and 41 transmit the vehicle travel map to the traveling vehicle, and each mounted vehicle receives the vehicle travel map by a receiving circuit, and the processing circuit 15
Processes the vehicle travel map and displays it on the map display means 21. The map display means 21 displays the second beacon 4
The position of each vehicle is displayed based on the vehicle running map from 0 and 41.

The PN code modulation circuit 29 outputs a modulation signal based on a long code length PN code. Here, the PN code having a long code length is a PN code having a code length sufficient to detect all vehicles with high accuracy.

The single pulse generating circuit 30 outputs a single pulse wave modulated by PN code toward an object such as a vehicle or an obstacle. The single pulse generation circuit 30 having directivity is used, and the processing circuit 15 outputs a single pulse wave generation signal and outputs a count start signal to the count pulse generation circuit 31 at the same time. The count pulse generation circuit 31 outputs a clock signal to the count circuit 32. The counting circuit 32 counts the clock signal.

The reflected wave receiving circuit 33 receives the reflected wave of a single pulse wave reflected by the object, and a correlation detecting circuit 34
Detects the correlation signal based on the reflected wave, and the counting circuit 31 measures the transmission / reception time from the transmission start time of the single pulse wave to the correlation signal detection time using the correlation signal detected by the correlation detection circuit 34 as a counting end signal. Then, the processing circuit 15 measures the distance from the own vehicle to another vehicle based on the speed of the radio wave and the transmission / reception time.

The distance and direction to each vehicle existing around the vehicle are obtained by performing this measurement at predetermined angles in a 360-degree circumferential direction of the vehicle. For mounted vehicles, vehicle position information can be obtained by communication between the mounted vehicles, so that the distance and direction to the vehicle measured by the distance measuring means 18 are mainly used to determine the position of a non-mounted vehicle.

As shown in FIGS. 5 and 6, magnetic markers (magnets) are buried on the highway 1 at predetermined intervals. Either the N pole or the S pole of the magnetic marker is directed to the road surface, and the arrangement pattern of the polarity composed of the N pole and the S pole follows the M sequence pattern. Here, the magnetic pole N
Corresponds to the chip information “0” of the M-sequence pattern, and the magnetic pole S corresponds to the chip information “1”. In FIG. 5, magnetic markers are embedded according to the M-sequence pattern of m = 8 (m is the number of stages of the shift register). If eight consecutive chips of the magnetic marker are regarded as one binary code, it can correspond to 256 different positions.
For example, if m = 10, it can correspond to 1023 positions, and if magnetic markers are embedded at 1 m intervals,
Between 1023 m, the position can be specified every 1 m. As the order m is increased, for example, the order m = 1
00, it is large enough to cover expressways in Japan at 1 m intervals. Then, a road traffic system for specifying the position of the road by the magnetic markers embedded at predetermined intervals on the highway 1 is configured.

The magnetic sensor 35 detects magnetism while the vehicle is running and outputs a detection signal to a waveform shaping circuit 36. The waveform shaping circuit 36 generates a "0" or "1" clock signal based on the detection signal. Output to the shift register 37. Here, the shift register 37 has the order m = 8 of the M-sequence pattern.
Has the number of stages corresponding to. The shift register 37 acquires a binary code corresponding to the M-sequence pattern during traveling.

In FIG. 5, it is assumed that the mounted vehicle is traveling from left to right, and eight detection signals (N, N, N, N, N, N, N, S) are acquired by the magnetic sensor 35. It is assumed that At this time, the content of the shift register 37 is “10000000”.

When the vehicle further travels and the magnetic sensor 35 detects the next magnetic marker (polarity N), the content of the shift register 37 becomes "01000000", and a signal of chip information "0" is output from the highest rank. Output to the processing circuit 15. The shift register 37 outputs chip information “0” or “1” from the uppermost stage to the processing circuit 15 every time a detection signal is detected by the magnetic sensor 35.

As shown in the flowchart of FIG. 7, the processing circuit 15 sets an initial value "0" to a variable n of the count memory (S.1), and determines whether there is an output from the uppermost stage of the shift register 37. Is determined (S.2), and the content of the variable n is counted up by “+1” (S.3). Next, the processing circuit 15 determines whether or not the variable n is equal to or less than the order m (S.
4) When the variable n is smaller than the order m, the output from the uppermost stage of the shift register 37 is stored in a memory in a time-series order (S.5), and whether or not the variable n is equal to the order m is determined. It is determined (S.6), and when the variable n and the degree m do not match, S.P. Returning to S.2, 2 to S.R. 5 is repeated, and when the variable n and the degree m match, the binary code information stored in the memory in chronological order is compared with the binary code information stored in the road map memory 20. The circuit 15 acquires the vehicle position information of the own vehicle (S.7). The processing circuit 15 displays the vehicle position information of the own vehicle on the vehicle map display means 21 (S.8). Returning to 2, the presence or absence of the output of the shift register 37 is detected.

The processing circuit 15 has a 8, after the output of the shift register 37 is input, "+1" is added to the contents of the variable n (S.3), and it is determined whether or not the variable n is equal to or less than the order m (S.3). 4), when the variable n is greater than the degree m, Move to 9. S. In 9,
The bit information of the memory stored at the highest order is discarded. Next, the processing circuit 15 shifts the bit information stored in the lower memory to the upper memory one by one (S.
10), the output of the uppermost stage of the shift register 37 which is actually obtained is stored in the lowermost memory (S.11), and
Move to 7. The processing circuit 15 again stores the binary code information stored in the memory in chronological order in the road map memory 2.
The vehicle position information is obtained by collating with the binary code information stored in “0”.

The processing circuit 15 executes a series of processing S. 1 to S.S. By repeating step 11, it functions as position determining means for determining the position of the host vehicle.

The processing circuit 15 creates vehicle position map information based on the acquired vehicle position information of each mounted vehicle and the vehicle position information of the non-mounted vehicle, and displays the vehicle position map information on the map display means 21. Is displayed as shown in FIG.

In FIG. 8, "x" indicates that several vehicles are running before and after the on-board vehicle 4 as its own vehicle.

Here, focusing on the vehicle 4 shown in FIG.
In the on-board vehicle 4, the subsequent on-board vehicle 7 is hidden behind the non-on-board vehicles 5 and 6, and the position of the on-board vehicle 7 cannot be specified. By doing so, the vehicle map information of the mounted vehicles 8 and 9 is obtained, whereby the distance measuring unit 1 is hidden behind other vehicles.
8, the position of the non-mounted vehicle 7 whose position cannot be specified can be specified.

In each mounted vehicle, between the second beacon 40 and the second beacon 41, the position of each vehicle is acquired by the two-way communication between vehicles and the distance measuring means, and the vehicle position information is displayed on a map. In order to avoid the map information of the own vehicle becoming suspicious during traveling, the vehicle information is accurately updated from the second beacon and the map information is updated.

[0035]

According to the present invention, a magnetic marker is buried at a predetermined interval on a road, and a magnetic sensor for detecting the magnetic marker, and an arrangement pattern of magnetic poles of the magnetic marker are detected from a detection signal of the magnetic sensor. Since the processing means for reading and specifying the position of the vehicle is provided in the vehicle,
The position of the vehicle can be specified precisely.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a road traffic system based on bidirectional communication between vehicles to which a road traffic system according to the present invention is applied.

FIG. 2 is an overall view of a circuit mounted on a vehicle used in the two-way communication system between vehicles.

FIG. 3 is a schematic diagram showing an internal configuration of a first beacon shown in FIG.

FIG. 4 is a diagram illustrating a shift register as an example of a PN code assignment generation circuit.

FIG. 5 is a diagram conceptually illustrating an example of an arrangement of polarities of magnetic markers embedded in a road.

FIG. 6 is a diagram illustrating an example of detection of a magnetic marker by running a vehicle.

FIG. 7 is a flowchart showing a procedure for specifying a vehicle position based on a detection signal obtained by a magnetic marker.

FIG. 8 is a diagram showing an example of a vehicle travel map displayed on a map display means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Expressway 2-14 ... Vehicle 15 ... Processing circuit (processing means) 35 ... Magnetic sensor

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Claims (3)

[Claims] 1. A road traffic system for specifying a position of a vehicle traveling on a road, comprising: a magnetic marker embedded in the road at a predetermined interval; a magnetic sensor for detecting the magnetic marker; Processing means for reading the arrangement pattern of the magnetic poles of the magnetic marker from the detection signal to specify the position of the vehicle, provided in the vehicle. 2. The road traffic system according to claim 1, wherein one magnetic pole of said magnetic marker is directed to a road surface, and the position of the vehicle is specified by an arrangement pattern of the magnetic poles directed to the road surface. 3. The road traffic system according to claim 1, wherein the arrangement pattern of the magnetic poles is an M-sequence pattern.