KR20220074688A - Vehicle localization method for urban environment using road traffic infrastructure and wireless communication technology - Google Patents

Abstract

The present embodiments provide a traffic signal system and vehicle capable of estimating the location and moving direction of a vehicle according to the driving state of the vehicle at an intersection based on wireless or mobile communication and improving positioning accuracy.

Description

A method of estimating the location of a city vehicle using road traffic facilities and wireless communication technology

The technical field to which the present invention pertains relates to a traffic signal system capable of estimating the location of an urban vehicle, and a vehicle communicating with the traffic signal system.

The content described in this section merely provides background information for the present embodiment and does not constitute the prior art.

Although very precise positioning accuracy is required for estimating the location of a vehicle, the conventional location estimation technique using a global positioning system (GPS) does not have high positioning accuracy in an urban environment.

US 2016/0035223 (2016.02.04.) KR 10-1962181 (2019.03.20.) KR 10-2019-0061395 (2019.06.05.) KR 10-2018-0040760 (2018.04.23.)

Embodiments of the present invention have a main purpose of estimating the location and movement direction of a vehicle according to the driving state of the vehicle at an intersection based on communication between the vehicle and a traffic signal system.

Other objects not specified in the present invention may be additionally considered within the scope that can be easily inferred from the following detailed description and effects thereof.

According to an aspect of this embodiment, in a vehicle, a first communication unit for transmitting and receiving a message to and from a traffic signal system; It is connected to the first communication unit, divides the driving state of the vehicle into a stopped state, a departure state, and a moving state, and transmits and receives a message to and from the traffic signal system according to the stopped state, the departure state, and the moving state a first processing unit that processes differently; and a moving device connected to the first processing unit and configured to move the vehicle.

The traffic signal system includes a plurality of traffic lights installed at different positions at an intersection, and in the stopped state, the first communication unit periodically transmits an arrival message to the traffic signal system, When the signal is a red signal, the first communication unit receives an arrival response message and a stop status message from the traffic signal system, and the first communication unit transmits a stop status response message and a pilot signal for positioning to the traffic signal system, and , the first communication unit may receive the vehicle location message estimated by using the arrival time and signal strength of the pilot signal by a plurality of traffic lights installed at different positions at the intersection.

The traffic signal system includes traffic lights installed at a plurality of adjacent intersections, and in the starting state, when the traffic signal for the traveling direction of the vehicle is converted to a green signal, the first communication unit can start from the traffic signal system Receiving the message, the first communication unit receives the departure possible message and after a preset waiting time elapses, transmits a departure status response message and a pilot signal for positioning to the traffic signal system, and receives the departure status response message One traffic light may transmit the vehicle entry message to the traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal.

The traffic signal system includes traffic lights installed at a plurality of adjacent intersections, and in the departure state, the traffic signal for the traveling direction of the vehicle is not considered, and the first communication unit sends a departure state response message to the traffic signal system and A traffic light that transmits a pilot signal for positioning and receives the departure status response message may transmit a vehicle entry message to a traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal.

The traffic signal system includes traffic lights installed at a plurality of adjacent intersections, and in the moving state, the first communication unit periodically transmits an arrival message to the traffic signal system, and the traffic signal for the traveling direction of the vehicle is recorded. When it is a signal, the first communication unit receives an arrival response message and a movement status message from the traffic signal system, and the first communication unit transmits a movement status response message and a pilot signal for positioning to the traffic signal system, and the movement The traffic light receiving the status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal, and the traffic light receiving the movement status response message transmits the pilot signal , a vehicle location message estimated using the moving speed and moving direction of the vehicle may be received.

According to another aspect of this embodiment, in the traffic signal system, a second communication unit for transmitting and receiving messages with the vehicle; and a second processing unit connected to the second communication unit and configured to differently process messages transmitted and received with the vehicle according to the driving state of the vehicle divided into a stopped state, a departure state, and a moving state. do.

The traffic signal system includes a plurality of traffic lights installed at different positions at an intersection, and in the stopped state, the second communication unit receives an arrival message from the traffic signal system, and a traffic signal for a traveling direction of the vehicle When it is a red signal, the second communication unit transmits an arrival response message and a stop status message to the vehicle, the second communication unit receives a stop status response message and a pilot signal for positioning from the vehicle, and the second processing unit The location of the vehicle is estimated using the arrival time and signal strength of the pilot signal by a plurality of traffic lights installed at different locations at the intersection, and the second communication unit is a vehicle location message for the location of the vehicle in the vehicle can be sent.

The traffic signal system includes traffic lights installed at a plurality of adjacent intersections, and in the starting state, when the traffic signal for the traveling direction of the vehicle is converted to a green signal, the second communication unit transmits a departure possible message to the vehicle. transmitting, the second communication unit receives a departure status response message and a pilot signal for positioning from the vehicle, the second processing unit estimates the position and movement direction of the vehicle using the pilot signal, and the second communication unit The vehicle entrance message can be delivered to the traffic light of the next intersection.

The traffic signal system includes traffic lights installed at a plurality of adjacent intersections, and in the departure state, the second communication unit sends a departure state response message and a pilot signal for positioning from the vehicle before transmitting the departure enable message to the vehicle. received, the second processing unit may estimate the position and movement direction of the vehicle using the pilot signal, and the second communication unit may transmit the vehicle entry message to the traffic light of the next intersection.

The traffic signal system includes traffic lights installed at a plurality of adjacent intersections, and in the moving state, the second communication unit receives an arrival message from the vehicle, and when the traffic signal for the traveling direction of the vehicle is a green signal, the A second communication unit transmits an arrival response message and a movement status message to the vehicle, the second communication unit receives a movement status response message and a pilot signal for positioning from the vehicle, and the second processing unit uses the pilot signal to estimate the location and movement direction of the vehicle, the second communication unit transmits a vehicle entry message to a traffic light of the next intersection, and the second processing unit uses the pilot signal and the vehicle movement speed and movement direction to determine the vehicle's movement direction. , and the second communication unit may transmit a vehicle location message for the location of the vehicle to the vehicle.

As described above, according to the embodiments of the present invention, there is an effect of estimating the location and movement direction of a vehicle according to the driving state of the vehicle at an intersection based on communication between the vehicle and the traffic signal system and improving the positioning accuracy.

Even if it is an effect not explicitly mentioned herein, the effects described in the following specification expected by the technical features of the present invention and their potential effects are treated as if they were described in the specification of the present invention.

1 is a diagram illustrating an intersection according to a traffic signal system.
2 is a block diagram illustrating a vehicle according to an embodiment of the present invention.
3 is a block diagram illustrating a traffic signal system according to another embodiment of the present invention.
4 is a diagram illustrating a message transmitted and received in a stopped state between a vehicle and a traffic signal system according to embodiments of the present invention.
5 is a diagram illustrating a message transmitted and received in a departure state between a vehicle and a traffic signal system according to embodiments of the present invention.
6 is a diagram illustrating messages transmitted and received in a moving state between a vehicle and a traffic signal system according to embodiments of the present invention.

Hereinafter, in the description of the present invention, if it is determined that the subject matter of the present invention may be unnecessarily obscure as it is obvious to those skilled in the art with respect to related known functions, the detailed description thereof will be omitted, and some embodiments of the present invention will be described. It will be described in detail with reference to exemplary drawings.

1 is a diagram illustrating an intersection according to a traffic signal system, FIG. 2 is a block diagram illustrating a vehicle according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating a traffic signal system according to another embodiment of the present invention It is a block diagram.

In the present invention, the driving state of the vehicle is divided into three types: stop, start, and move. The present invention performs different operations according to the driving state of the vehicle.

In the stationary state, the traffic signal system performs high-precision localization.

In the starting state, the traffic signal system estimates the moving direction of the vehicle, transmits vehicle entry information to the intersection reached when the vehicle proceeds in the estimated moving direction, and performs hand-off.

While in motion, the traffic signal system corrects the position in real time, improving the estimation accuracy.

In each state, signals are transmitted and received between the vehicle and the system. Depending on each state, the vehicle and the traffic signal system exchange different messages. A corresponding message may have a different configuration method and a different transmission method depending on the communication standard used by the system.

The location estimation system of the present invention can be used using road traffic facilities and infrastructure. In particular, it is possible to estimate the location more accurately by using it in conjunction with the traffic signal system. It can be installed and used at traffic lights existing at intersections.

The wireless communication used in this embodiment may be used in accordance with various communication methods and standards, such as commercial mobile communication technologies (LTE, NR, etc.) and dedicated short range communication (DSRC). For example, next-generation mobile communication such as 5G and 6G may be applied.

The location estimation system includes a vehicle 100 and a traffic signal system 200 .

The vehicle 100 includes a first communication unit 110 , a first processing unit 120 , and a mobile device 130 . The vehicle 100 may be an autonomous driving vehicle.

The first communication unit 110 transmits and receives messages to and from the traffic signal system 200 .

The first processing unit 120 is connected to the first communication unit 110 , and divides the driving state of the vehicle 100 into a stopped state, a starting state, and a moving state. The first processing unit 120 differently processes messages transmitted and received with the traffic signal system 200 according to the stop state, the departure state, and the moving state.

The vehicle 100 may correct its own location information or a driving plan by using the received location message.

The moving device 130 is connected to the first processing unit 120 and moves the vehicle 100 . It may be a drive device with some kind of wheel.

The traffic signal system 200 includes a second communication unit 210 and a second processing unit 220 . The traffic signal system 200 may include a plurality of traffic lights installed at different positions at the intersection. The traffic signal system 200 may include traffic lights installed at a plurality of adjacent intersections.

The second communication unit 210 transmits and receives messages to and from the vehicle 100 .

The second processing unit 220 is connected to the second communication unit 210 and differently processes messages transmitted and received with the vehicle according to the driving state of the vehicle divided into a stopped state, a departure state, and a moving state.

4 is a diagram illustrating a message transmitted and received in a stopped state between a vehicle and a traffic signal system according to embodiments of the present invention.

The vehicle periodically transmits an ARV message (vehicle arrival information). The traffic lights at the intersection receive the ARV message to confirm that the vehicle is approaching, and check the traffic signal in the vehicle's driving direction. When the traffic signal for the vehicle's traveling direction is a red light, the traffic light transmits an SC-A message (confirming the status of A) to the vehicle along with an ARV ACK message (response to the ARV message). After receiving the ARV ACK and SC-A, the vehicle stops and transmits RS (pilot signal for positioning) together with the SC-A ACK message (response to SC-A). After receiving the SC-A ACK, the traffic lights installed at different positions of the intersection estimate the vehicle's location using the difference in arrival time of the RS signal transmitted by the vehicle and the difference in received signal strength. After the location estimation is completed, the traffic light transmits a LOC message (information about the estimated location) to the vehicle to the vehicle.

In the stationary state, the first communication unit of the vehicle periodically transmits an arrival message to the traffic signal system. When the traffic signal for the traveling direction of the vehicle is a red signal, the first communication unit receives the arrival response message and the stop status message from the traffic signal system. The first communication unit transmits a stop state response message and a pilot signal for positioning to the traffic signal system. The first communication unit receives the vehicle position message estimated by using the arrival time and signal strength of the pilot signal by a plurality of traffic lights installed at different positions at the intersection.

In the stopped state, the second communication unit of the traffic signal system receives an arrival message from the traffic signal system. When the traffic signal for the traveling direction of the vehicle is a red signal, the second communication unit transmits an arrival response message and a stop status message to the vehicle. The second communication unit receives a stop state response message and a pilot signal for positioning from the vehicle. The second processing unit estimates the position of the vehicle by using the arrival time and signal strength of the pilot signal by a plurality of traffic lights installed at different positions at the intersection. The second communication unit transmits a vehicle location message about the location of the vehicle to the vehicle.

5 is a diagram illustrating a message transmitted and received in a departure state between a vehicle and a traffic signal system according to embodiments of the present invention.

Departure of a vehicle is divided into cases where a signal is required (go straight and turn left in Korea) and when a signal is not required (turn right in Korea). If a signal is required, when the traffic signal turns into a green light, the traffic light sends an SC-B message (confirming that it is in the B state) to vehicles traveling in that direction. After receiving the SC-B message and starting acceleration, the vehicle transmits RS along with the SC-B ACK message (response to SC-B) after a certain period of time has elapsed. Under the condition that the traffic signal system sends an SC-B message and the vehicle sends an SC-B ACK message after a preset waiting time has elapsed, the traffic signal system determines that the vehicle's moving direction is a straight-line and left-turn path (lane). can The traffic light receiving the SC-B ACK estimates the vehicle's location using RS to estimate the vehicle's moving direction.

Using the estimated vehicle movement direction, a VHA message (vehicle entry information) is delivered to the next intersection that the vehicle travels and arrives, and hand-off is performed. If the vehicle moves in a direction that does not require a signal, the vehicle transmits an SC-B ACK without receiving the SC-B message and performs the same process as above. In a condition in which the SC-B ACK message is received before the SC-B message is transmitted, the traffic signal system may determine that the moving direction of the vehicle is a right turn path (lane).

When a traffic signal for a traveling direction of the vehicle is converted to a green signal in a departure state requiring a signal, the first communication unit of the vehicle receives a departure enable message from the traffic signal system. The first communication unit receives the departure possible message and transmits a departure status response message and a pilot signal for positioning to the traffic signal system after a preset waiting time has elapsed. The traffic light receiving the departure status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal.

In the starting state where a signal is required, when the traffic signal for the traveling direction of the vehicle is converted to a green signal, the second communication unit of the traffic signal system transmits a departure enable message to the vehicle. The second communication unit receives a departure status response message and a pilot signal for positioning from the vehicle. The second processing unit estimates the position and the moving direction of the vehicle by using the pilot signal. The second communication unit transmits the vehicle entry message to the traffic light of the next intersection.

In the signal-free departure state, without considering the traffic signal for the traveling direction of the vehicle, the first communication unit of the vehicle transmits a departure state response message and a pilot signal for positioning to the traffic signal system. The traffic light receiving the departure status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal.

In the signal-free departure state, the second communication unit of the traffic signal system receives the departure state response message and the pilot signal for positioning from the vehicle before sending the departure enable message to the vehicle. The second processing unit estimates the position and the moving direction of the vehicle by using the pilot signal. The second communication unit transmits the vehicle entry message to the traffic light of the next intersection.

6 is a diagram illustrating messages transmitted and received in a moving state between a vehicle and a traffic signal system according to embodiments of the present invention.

Vehicles periodically transmit ARV messages. Traffic lights at intersections receive ARV messages to confirm that the vehicle is approaching. Check the traffic signals in the direction the vehicle is traveling. When the traffic signal for the traveling direction of the vehicle is a green signal, the traffic light transmits an SC-C message (confirming state C) along with an ARV ACK message to the vehicle. The vehicle moves and receives the ARV ACK and SC-C and then transmits the SC-C ACK message (response to the SC-C) and RS. Traffic lights estimate the vehicle's moving direction through RS and deliver the VHA to the intersection the vehicle is heading to based on this. At the same time, the LOC message is transmitted to the vehicle by correcting and updating the location information of the vehicle using the RS and the moving speed and direction of the vehicle. If the traffic signal changes to a red light when the vehicle enters the intersection, the process is switched to the state A and the corresponding process is performed.

In the moving state, the first communication unit of the vehicle periodically transmits an arrival message to the traffic signal system. When the traffic signal for the traveling direction of the vehicle is a green signal, the first communication unit receives the arrival response message and the movement status message from the traffic signal system. The first communication unit transmits a movement status response message and a pilot signal for positioning to the traffic signal system. The traffic light receiving the movement status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal. The traffic light receiving the movement status response message receives the vehicle position message estimated using the pilot signal, the vehicle's moving speed and the moving direction.

In the mobile state, the second communication unit of the traffic signaling system receives an arrival message from the vehicle. When the traffic signal for the traveling direction of the vehicle is a green signal, the second communication unit transmits an arrival response message and a movement status message to the vehicle. The second communication unit receives a movement status response message and a pilot signal for positioning from the vehicle. The second processing unit estimates the position and the moving direction of the vehicle by using the pilot signal. The second communication unit transmits the vehicle entry message to the traffic light of the next intersection. The second processing unit estimates the position of the vehicle by using the pilot signal, the moving speed and the moving direction of the vehicle. The second communication unit transmits a vehicle location message about the location of the vehicle to the vehicle.

The vehicle and traffic signal system may include at least one processor, a computer readable storage medium, and a communication bus.

The processor may control the vehicle and traffic signal system to operate. For example, the processor may execute one or more programs stored in a computer-readable storage medium. The one or more programs may include one or more computer-executable instructions, which, when executed by a processor, may be configured to cause vehicles and traffic signal systems to perform operations in accordance with the exemplary embodiment.

The computer-readable storage medium is configured to store computer-executable instructions or program code, program data and/or other suitable form of information. A program stored in a computer-readable storage medium includes a set of instructions executable by a processor. In one embodiment, the computer-readable storage medium includes memory (volatile memory, such as random access memory, non-volatile memory, or a suitable combination thereof), one or more magnetic disk storage devices, optical disk storage devices, flash memory device and other types of storage media that can be accessed by vehicles and traffic signal systems and can store desired information, or a suitable combination thereof.

A communication bus interconnects various other components of the vehicle and traffic signaling system, including processors, computer-readable storage media, and the like.

Vehicle and traffic signaling systems may also include one or more input/output interfaces and one or more communication interfaces that provide interfaces for one or more input/output devices. The input/output interface and the communication interface are coupled to the communication bus. The input/output device may be connected to the vehicle and other components of the traffic signal system via the input/output interface.

The vehicle and traffic signal system may be implemented in a logic circuit by hardware, firmware, software, or a combination thereof, and may be implemented using a general-purpose or special-purpose computer. The device may be implemented using a hardwired device, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like. In addition, the device may be implemented as a system on chip (SoC) including one or more processors and controllers.

The vehicle and traffic signal system may be mounted in a form of software, hardware, or a combination thereof on a computing device or server provided with hardware elements. A computing device or server includes all or part of a communication device such as a communication modem for performing communication with various devices or wired/wireless communication networks, a memory for storing data for executing a program, and a microprocessor for executing operations and commands by executing the program. It can mean a variety of devices, including

In Figures 4 to 6, it is described as executing each process sequentially, but this is only an exemplary description, and those skilled in the art are shown in Figs. Various modifications and variations may be applied by changing the described order, executing one or more processes in parallel, or adding other processes.

The operations according to the present embodiments may be implemented in the form of program instructions that can be performed through various computer means and recorded in a computer-readable medium. Computer-readable medium represents any medium that participates in providing instructions to a processor for execution. Computer-readable media may include program instructions, data files, data structures, or a combination thereof. For example, there may be a magnetic medium, an optical recording medium, a memory, and the like. A computer program may be distributed over a networked computer system so that computer readable code is stored and executed in a distributed manner. Functional programs, codes, and code segments for implementing the present embodiment may be easily inferred by programmers in the art to which this embodiment belongs.

The present embodiments are for explaining the technical idea of the present embodiment, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present embodiment.

Claims (10)

in a vehicle,
a first communication unit for transmitting and receiving messages to and from the traffic signal system;
It is connected to the first communication unit, divides the driving state of the vehicle into a stopped state, a departure state, and a moving state, and transmits and receives a message to and from the traffic signal system according to the stopped state, the departure state, and the moving state a first processing unit that processes differently; and
and a mobile device connected to the first processing unit and configured to move the vehicle. According to claim 1,
The traffic signal system includes a plurality of traffic lights installed at different positions at the intersection,
In the stopped state,
The first communication unit periodically transmits an arrival message to the traffic signal system,
When the traffic signal for the traveling direction of the vehicle is a red signal, the first communication unit receives an arrival response message and a stop status message from the traffic signal system,
The first communication unit transmits a stop state response message and a pilot signal for positioning to the traffic signal system,
The first communication unit receives the vehicle location message estimated by using the arrival time and signal strength of the pilot signal by a plurality of traffic lights installed at different positions in the intersection. According to claim 1,
The traffic signal system includes traffic lights installed at a plurality of adjacent intersections,
In the starting state,
When the traffic signal for the traveling direction of the vehicle is converted to a green signal, the first communication unit receives a departure possible message from the traffic signal system,
The first communication unit receives the departure possible message and transmits a departure status response message and a pilot signal for positioning to the traffic signal system after a preset waiting time has elapsed,
The traffic light receiving the departure status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the vehicle's position and moving direction estimated using the pilot signal. According to claim 1,
The traffic signal system includes traffic lights installed at a plurality of adjacent intersections,
In the starting state,
Without considering the traffic signal for the direction of travel of the vehicle,
The first communication unit transmits a departure status response message and a pilot signal for positioning to the traffic signal system,
The traffic light receiving the departure status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the vehicle's position and moving direction estimated using the pilot signal. According to claim 1,
The traffic signal system includes traffic lights installed at a plurality of adjacent intersections,
In the moving state,
The first communication unit periodically transmits an arrival message to the traffic signal system,
When the traffic signal for the traveling direction of the vehicle is a green signal, the first communication unit receives an arrival response message and a movement status message from the traffic signal system,
The first communication unit transmits a movement status response message and a pilot signal for positioning to the traffic signal system,
The traffic light receiving the movement status response message transmits the vehicle entry message to the traffic light of the next intersection in consideration of the location and movement direction of the vehicle estimated using the pilot signal,
The traffic light receiving the movement status response message receives the vehicle position message estimated using the pilot signal, the moving speed and the moving direction of the vehicle. A traffic signal system comprising:
a second communication unit for transmitting and receiving messages to and from the vehicle; and
and a second processing unit connected to the second communication unit and configured to differently process messages transmitted and received with the vehicle according to the driving state of the vehicle divided into a stopped state, a starting state, and a moving state. 7. The method of claim 6,
The traffic signal system includes a plurality of traffic lights installed at different positions at the intersection,
In the stopped state,
The second communication unit receives an arrival message from the traffic signal system,
When the traffic signal for the traveling direction of the vehicle is a red signal, the second communication unit transmits an arrival response message and a stop status message to the vehicle,
The second communication unit receives a stop state response message and a pilot signal for positioning from the vehicle,
The second processing unit estimates the position of the vehicle by using the arrival time and signal strength of the pilot signal by a plurality of traffic lights installed at different positions at the intersection,
The traffic signal system, characterized in that the second communication unit transmits a vehicle location message for the location of the vehicle to the vehicle. 7. The method of claim 6,
The traffic signal system includes traffic lights installed at a plurality of adjacent intersections,
In the starting state,
When the traffic signal for the traveling direction of the vehicle is converted to a green signal, the second communication unit transmits a departure possibility message to the vehicle,
The second communication unit receives a departure status response message and a pilot signal for positioning from the vehicle,
The second processing unit estimates the position and movement direction of the vehicle by using the pilot signal, and the second communication unit transmits a vehicle entry message to a traffic light of a next intersection. 7. The method of claim 6,
The traffic signal system includes traffic lights installed at a plurality of adjacent intersections,
In the starting state,
The second communication unit receives a departure status response message and a pilot signal for positioning from the vehicle before transmitting the departure possible message to the vehicle,
The second processing unit estimates the position and movement direction of the vehicle by using the pilot signal, and the second communication unit transmits the vehicle entry message to the traffic light of the next intersection. 7. The method of claim 6,
The traffic signal system includes traffic lights installed at a plurality of adjacent intersections,
In the moving state,
The second communication unit receives an arrival message from the vehicle,
When the traffic signal for the traveling direction of the vehicle is a green signal, the second communication unit transmits an arrival response message and a movement status message to the vehicle,
The second communication unit receives a movement status response message and a pilot signal for positioning from the vehicle,
The second processing unit estimates the position and movement direction of the vehicle by using the pilot signal, and the second communication unit transmits a vehicle entry message to a traffic light of the next intersection,
The second processing unit estimates the position of the vehicle by using the pilot signal, the moving speed and the moving direction of the vehicle, and the second communication unit transmits a vehicle position message about the position of the vehicle to the vehicle. traffic signal system.

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