JPH11265497A - Road traffic system by two-way communication between vehicles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a road traffic system capable of grasping positions, running conditions of other vehicles centering around an own vehicle on which a two-way transmitting and receiving means between vehicles is mounted even under traffic conditions in which the vehicles on which the two-way transmitting and receiving means between vehicles is mounted or the vehicles on which no such means is mounted coexist. SOLUTION: Each vehicle on which a transmitting and receiving means for two-way communication between vehicles is mounted is provided with a distance measuring means 18 of the distance and the direction from the own vehicle to other vehicles. A transmission signal is outputted by radio from the own vehicle to the outside by performing PN code modulation to vehicle information in which at least vehicle position information is included by each transmitting means 16. The vehicle position information on each of other vehicles on which the transmitting and receiving means for two-way communication between vehicles is mounted is acquired by receiving the transmission signal from other vehicles on which the two-way transmitting and receiving means between vehicles is mounted and decoding the signal by a correlation circuit by each receiving means 17. The vehicle position information on the vehicles on which no transmitting and receiving means for two-way communication between vehicles is not mounted is acquired by the distance measuring means 18 by each of the vehicles on which the transmitting and receiving means for two-way communication between vehicles is not mounted and each of the vehicles on which the transmitting and receiving means for two-way communication between vehicles is mounted is provided with a processing means 15 to create the positions of other vehicles centering around the own vehicle as a vehicle running map based on each piece of the vehicle position information.

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 using two-way communication between vehicles, and more particularly, to so-called front seat information such as vehicle position information, vehicle speed information, and brake information as to whether or not a brake is applied. The present invention relates to a road traffic system using an inter-vehicle two-way communication system for transmitting data to a vehicle.

[0002]

2. Description of the Related Art In recent years, traffic problems such as traffic accidents and traffic congestion have become more serious with the increase in vehicles, and information communication systems have been introduced to solve these traffic accidents and traffic congestion. Research and development are underway to improve safety and solve congestion problems.

For this information communication system, it is considered to employ a method called spread spectrum communication which is excellent in interference resistance and interference resistance. Here, the spread spectrum communication is a method of performing communication by modulating front information using a PN code.

Conventionally, in a road traffic system using two-way communication between vehicles, it has been considered to construct the system only for vehicles equipped with transmission / reception means for two-way communication between vehicles.

[0005]

However, some vehicles are not equipped with a vehicle-to-vehicle two-way communication transmission / reception means. It is essential to think that the vehicle and the vehicle are mixed and traveling on the road. Under such traffic conditions, it is difficult to grasp the position of the other vehicle and the running condition of the vehicle around the own vehicle. When constructing a road traffic system based on two-way communication between vehicles, creating a vehicle running map in a mixed state becomes an issue.

[0006] When a network based on two-way communication between vehicles is constructed, front seat information such as position information, speed information, brake information, etc. of a vehicle existing around the own vehicle is important. The front seat information of a vehicle located farther away from the vehicle is less important, and in consideration of this, a network by two-way communication between vehicles should be constructed.

In particular, when constructing a road traffic system based on two-way communication between vehicles by modulating the front seat information with PN code, if each vehicle is identified by associating a different PN code with all vehicles, A PN code having a large code length (a PN code having a long code length) for identifying each of the ten million and several hundred million mounted vehicles is prepared and the front seat information is transmitted. When demodulating and receiving the modulated front sheet information,
Correlation detection circuits of the number corresponding to the code length of the PN code must be prepared for each vehicle, and the number of correlation detection circuits increases as the code length of the PN code increases. Is a problem.

Further, in the case of creating a vehicle running map of each vehicle existing near the own vehicle with the own vehicle as a center,
Although it is required to accurately obtain the position information of each vehicle, the method of obtaining the position information of the vehicle using the conventional GPS system identifies each vehicle existing within several meters from the own vehicle. It is difficult to accurately obtain the position.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the position and traveling state of another vehicle centering on the own vehicle can be determined even in a traffic situation in which mounted and non-mounted vehicles are mixed. It is an object of the present invention to provide a road traffic system with two-way communication between vehicles that can be grasped and has high possibility.

[0010]

According to a first aspect of the present invention, there is provided a road traffic system using vehicle-to-vehicle bidirectional communication, wherein the vehicle includes a vehicle-to-vehicle bidirectional communication transceiver. Each mounted vehicle is provided with distance measuring means for measuring a distance and a direction from the own vehicle to another vehicle, and each transmitting means performs PN code modulation on vehicle information including at least vehicle position information to transmit a signal. Wirelessly output from the own vehicle to the outside, each receiving means receives a transmission signal transmitted from another mounted vehicle and demodulates it by a correlation circuit to acquire vehicle position information of each other mounted vehicle, The vehicle acquires the position information of the non-equipped vehicle on which the inter-vehicle two-way communication transmission / reception means is not mounted by the distance measuring means. The position of Processing means for creating a two running map is provided.

In the road traffic system according to the present invention, a first beacon is provided at a predetermined interval in the vehicle traveling direction and along the road, and the first beacon has a short code length PN toward the mounted vehicle. PN for assigning code
PN code assignment signal generating means for transmitting a code assignment signal and response signal detection means for detecting a response signal from the onboard vehicle are provided, and each of the onboard vehicles is provided with a PN code assignment signal from the first beacon. And a PN code generation circuit for generating a PN code.

The road traffic system according to claim 3, wherein a second beacon is provided adjacent to the first beacon, a map making means is provided in a base station, and the first beacon is passed by a vehicle recognizing means. And the on-vehicle and non-on-vehicle vehicles are identified based on the response signal, and the map creating means has passed the first beacon every time the assignment of the short code length PN code by the first beacon is completed. A vehicle travel map is created based on the vehicle, and a PN code is assigned from the beginning to each of the subsequent on-board vehicles each time the assignment is completed, and the second beacon transmits a vehicle travel map to the on-board vehicle, The vehicle updates a vehicle travel map of its own vehicle based on the vehicle travel map.

According to a fourth aspect of the present invention, there is provided a road traffic system, wherein each on-vehicle vehicle has its own vehicle in order to identify the position of a non-on-vehicle which cannot be located by the distance measuring means of the own vehicle and cannot be located by the shadow of another vehicle. It is possible to obtain vehicle map information between the vehicle and another vehicle.

According to a fifth aspect of the present invention, in the road traffic system, the receiving means includes a number of correlation detection circuits corresponding to the short code length for detecting the correlation of the PN code.

According to a sixth aspect of the present invention, there is provided a road traffic system, wherein each distance measuring means transmits a single pulse wave modulated by a long code length PN code to each vehicle as a distance measuring signal. A correlation detection circuit for receiving a reflected wave of the ranging signal reflected from each vehicle and detecting a correlation signal, and a correlation signal from the correlation detection circuit from the start of transmission of a single pulse wave output from the transmission means Calculating means for measuring the transmission / reception time up to the point of detection and calculating the distance to each vehicle based on the transmission / reception time and the speed of the radio wave.

According to a seventh aspect of the present invention, there is provided a road traffic system, wherein magnets are buried in the roadway at equal intervals in a vehicle traveling direction, and the magnet has one of an N pole and an S pole directed to a road surface; A polarity sensor pattern consisting of an N-pole and an S-pole follows an M-sequence pattern, and the mounted vehicle detects a magnetism of each magnet and outputs a detection signal according to the M-sequence pattern; Position information determining means for determining chip position based on the binary code by regarding chip information including a predetermined number of consecutive chips of a pattern as one binary code is provided.

[0017]

FIG. 1 is a schematic view of a road traffic system according to the present invention, in which two-way communication between vehicles is used. 1 is a highway as a motorway, and 2-14 are running on the highway 1. Is shown. Each of the vehicles 2 to 14 is running from left to right. Vehicles 2-4, 8-1
Reference numerals 0, 12 to 14 denote mounted vehicles on which the inter-vehicle bidirectional transmitting / receiving device is mounted, and vehicles 5 to 7, 11 denote non-mounted vehicles on which the inter-vehicle bidirectional transmitting / receiving device is not mounted. It is assumed that the vehicle is traveling on the highway 1 in a mixed state.

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 transmitting means 16 comprises a carrier circuit 22, a PN code generating circuit 23, a modulating circuit 24, and a transmitting 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, 39 are provided at a predetermined interval L1 along the vehicle running direction, and at predetermined intervals L2 in the vehicle running direction with respect to the first beacons 38, 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.

The first beacons 38 and 39 are, as shown in FIG.
3, a response signal detection circuit 44 and a transmission / reception circuit 45 are provided.

Here, the PN code assignment generation 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 generation circuit 42 updates the code of the M-sequence pattern every time the on-board vehicle passes, and transmits code assignment information from the transmission / reception circuit 45 to the on-board 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 and outputs the front sheet information from the processing circuit 15 on the PN code given by the code assignment information, and outputs the 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 the range of the two-way communication is within 200 m before and after the vehicle, it is considered that there will be no interference.

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 by 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 modulated 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 generation 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 a single-pulse wave reflected by the object, and outputs a correlation detection 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 on-board vehicles, vehicle position information can be obtained by communication between on-board vehicles, and the distance and direction to the vehicle measured by the distance measuring means 18 are mainly used to determine the position of non-on-board vehicles.

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.

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 or not 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 chronological 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 obtained 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 the 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 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 obtained 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.

[0044]

According to the road traffic system based on the two-way communication between vehicles according to the first aspect of the present invention, a vehicle equipped with the two-way vehicle-to-vehicle transmission / reception means and a non-mounted vehicle without the two-way vehicle-to-vehicle transmission / reception means are mounted. Even in a traffic situation where vehicles are mixed, it is possible to grasp the position and traveling state of other vehicles around the own vehicle.

According to the road traffic system based on the two-way communication between vehicles according to the second aspect, since the PN code having a short code length is assigned to each on-board vehicle, two-way communication between each on-board vehicle is performed. The number of correlation detection circuits in the receiving means can be reduced, the cost of the receiving means for bidirectional communication between vehicles can be reduced, and a highly feasible system can be constructed.

According to the road traffic system based on the two-way communication between the vehicles according to the third aspect, the vehicle running map held by the own vehicle is updated based on the map creating means of the base station. Even if the accuracy of the vehicle travel map held by the vehicle deteriorates due to noise, it is possible to prevent the accuracy of the vehicle travel map from being deteriorated.

According to the road traffic system based on the two-way communication between vehicles according to the fourth aspect, each mounted vehicle can acquire a vehicle running map between the own vehicle and another vehicle. The distance measuring means can specify the position of a non-mounted vehicle that cannot be specified because it is hidden by the shadow of another vehicle.

According to the road traffic system based on the two-way communication between vehicles according to the seventh aspect, the magnet is provided on the road and the polarity is M.
Since it is decided to embed at a predetermined interval so as to follow the sequence pattern, the code length of the M sequence pattern is increased,
Acquiring a binary code consisting of a predetermined continuous code of the M-sequence pattern during traveling has an effect that the position of the mounted vehicle during traveling can be specified with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a road traffic system based on two-way communication between vehicles according to the present invention.

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) 16 ... Transmission means 17 ... Receiving means 18 ... Distance measuring means 28 ... Correlation circuit

Claims (7)

[Claims] 1. A vehicle having a vehicle-to-vehicle two-way communication transmitting / receiving means mounted thereon, and each mounted vehicle having the vehicle-to-vehicle two-way communication transmitting / receiving means measuring a distance and a direction from the own vehicle to another vehicle. Each transmitting means performs PN code modulation on the vehicle information including at least the vehicle position information and wirelessly outputs a transmission signal from the own vehicle to the outside, and each receiving means is transmitted from another mounted vehicle. The received transmission signal is received and demodulated by a correlation circuit to obtain vehicle position information of each of the other mounted vehicles, and each mounted vehicle has position information of a non-mounted vehicle that does not have a transmitting / receiving means for bidirectional communication between vehicles. Is provided by the distance measuring means, and each mounted vehicle is provided with processing means for creating the position of another vehicle as a vehicle travel map around the own vehicle based on the vehicle position information. by Road traffic system. 2. A first beacon is provided along a roadway at a predetermined interval in a vehicle running direction, and the first beacon is a PN code assignment signal for assigning a short code length PN code to the onboard vehicle. And a response signal detecting means for detecting a response signal from the onboard vehicle, wherein each of the onboard vehicles has a PN code based on a PN code allocation signal from the first beacon. 2. The road traffic system according to claim 1, further comprising a PN code generation circuit that generates the PN code. 3. A second beacon is provided adjacent to the first beacon, a map making means is provided in a base station, and the first beacon recognizes a passing vehicle by a vehicle recognizing means and is based on a response signal. The on-vehicle and non-on-vehicle vehicles are identified, and the map creating means creates a vehicle travel map based on the vehicles that have passed through the first beacon each time the first beacon assigns a short code length PN code. At the same time, each time the assignment is completed, a PN code is assigned to each subsequent on-board vehicle from the beginning, the second beacon transmits a vehicle running map to the on-board vehicle, and each on-board vehicle is based on the vehicle running map. 3. The road traffic system according to claim 2, wherein the vehicle travel map of the own vehicle is updated. 4. In order to identify the position of a non-mounted vehicle that cannot be located by the distance measuring means using the own vehicle and is hidden by the shadow of another vehicle, each mounted vehicle has a vehicle map between the own vehicle and the other vehicle. The road traffic system according to claim 3, wherein information can be obtained. 5. The road traffic system according to claim 2, wherein said receiving means includes a number of correlation detection circuits corresponding to a short code length for detecting a correlation of said PN code. 6. Each distance measuring means has a long code length PN.
Transmitting means for transmitting a single pulse wave modulated by a code as a ranging signal to each vehicle, a correlation detecting circuit for receiving a reflected wave of the ranging signal reflected from each vehicle and detecting a correlation signal, and Measuring the transmission / reception time from the start of transmission of the single pulse wave output from the transmission means to the detection of the correlation signal by the correlation detection circuit, and determining the distance to each vehicle based on the transmission / reception time and the speed of the radio wave. The road traffic system according to claim 2, further comprising a calculating unit that performs a calculation. 7. A magnet embedded in the road at equal intervals in the vehicle traveling direction, the magnet having one of an N-pole and an S-pole directed to a road surface and having a polarity comprising an N-pole and an S-pole. Is arranged according to the M-sequence pattern. The mounted vehicle includes a magnetic sensor that detects the magnetism of each of the magnets and outputs a detection signal according to the M-sequence pattern, and a predetermined number of continuous chips of the M-sequence pattern. Chip information is one of two
And position determining means for determining the position of the host vehicle based on the binary code as a binary code.
Road traffic system as described in.