JPH085716A - Road-to-vehicle communication system - Google Patents

Abstract

PURPOSE:To enable a communication system between on-road equipment and vehicle using optical signals to perform communication by surely directing the transmitter-receiver of on-an vehicle equipment to a beacon. CONSTITUTION:The light emitting section 10a of an on-road equipment transmits optical signals containing the positional information of the on-road equipment. The light receiving section 12a of an on-vehicle equipment receives the optical signals from the on-road equipment and the control section 12c of the on-road equipment detects the positional information contained in the optical signals and recognizes the relative position between its own equipment and a beacon. The beam direction changing section 12d and output changing section 12e of the on-vehicle equipment optimize and output the beam direction and based on the relative position so as to transmit and receive information to and from the beacon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road-to-vehicle communication system, and more particularly to a road-to-vehicle communication system using an optical signal.

[0002]

2. Description of the Related Art With the increase in traffic volume in recent years, many traffic congestions have occurred, and how to solve them has become an important issue. As one of the methods, there has been proposed a road-vehicle communication system that centrally manages the traveling state and road condition of each vehicle and supplies road information to each vehicle as appropriate. In a road-to-vehicle communication system, a roadside device (beacon) having a transmitter / receiver is installed at a desired point on the road, and communication is performed with an in-vehicle device including a transmitter / receiver mounted on a traveling vehicle by radio waves or light. , Collects traveling information from each vehicle and manages it collectively, and provides road conditions etc. to the in-vehicle device.

For example, in the control system disclosed in Japanese Patent Laid-Open No. 5-217097, a fan-shaped light beam is rotatively scanned from a light source station provided on the road toward a plurality of vehicle-mounted reflection stations, and each reflection station is scanned. Proposes a system that collects information on multiple vehicles by receiving the light from this light source station, emitting modulated reflected light toward the light source station, and detecting the reflected light from each reflecting station. Has been done. When performing two-way communication using a light beam in this way, the optical signal transmitted from the beacon is reliably received from the vehicle side, and,
It is important to accurately transmit the optical signal toward the beacon. In the above-mentioned conventional technology, the light source station (beacon)
The laser beam with a sharp directivity is rotationally scanned, and a retroreflector such as a corner cube is used on the reflection station (vehicle-mounted device) side to transmit an optical signal toward the beacon.

[0004]

However, since the structure for transmitting an optical signal to the beacon using a retroreflector such as a corner cube is basically based on the optical properties of the corner cube, its processing accuracy is high. Greatly influences
Not only is it difficult to transmit the optical signal to the beacon with high accuracy, but there is also the problem of increasing the cost of the vehicle-mounted device. Also, instead of using such an optical element,
A configuration in which an optical signal from a beacon is received and the position where the beacon is present is estimated by calculation from the intensity of the received signal and the like is also conceivable, but it is necessary to provide a separate calculation device, which also causes a problem of cost increase.

On the other hand, it is difficult to uniformly determine the installation position of the beacon due to road restrictions. For example, a beacon is installed directly above each lane, or a beacon is provided in the middle of two lanes. Therefore, various installation forms such as a side emission type that covers two lanes are considered, and therefore, it is difficult to reliably receive the optical signal from the beacon in the configuration in which the direction of the transmitter / receiver of the vehicle-mounted device is fixed. Also, it becomes difficult to transmit an optical signal to the beacon.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to reliably receive an optical signal from a beacon and to reliably transmit the optical signal toward the beacon. An object of the present invention is to provide an inexpensive road-vehicle communication system capable of improving communication efficiency.

[0007]

In order to achieve the above object, a road-vehicle communication system according to claim 1 is a road for performing optical communication between a roadside device including a roadside transceiver and a vehicle-mounted device including a vehicle-mounted transceiver. In the vehicle-to-vehicle communication system, the roadside device transmits an optical signal including the position information of the roadside transceiver, and the vehicle-mounted device receives the optical signal and detects the position of the roadside transceiver from the position information included in the optical signal. It is characterized by having a position specifying means for specifying a position.

In order to achieve the above object, the road-vehicle communication system according to a second aspect is the road-vehicle communication system according to the first aspect, wherein the vehicle-mounted device is further specified by the position specifying means. It is characterized by further comprising direction control means for controlling the direction of the on-vehicle transceiver according to the position.

In order to achieve the above object, the road-vehicle communication system according to a third aspect of the present invention is the road-vehicle communication system according to the first aspect or the second aspect, wherein the vehicle-mounted device further extends to a position specified by the position specifying means. Intensity control means for controlling the intensity of the optical signal transmitted from the in-vehicle transmitter / receiver in accordance with the distance of 1.

Further, in order to achieve the above object, the road-vehicle communication system according to claim 4 is the road-vehicle communication system according to claim 1 or claim 2 or claim 3, wherein the road unit further comprises: It is characterized in that an optical signal including position information of the next roadside device installed on the vehicle travel route is transmitted.

[0011]

In the road-to-vehicle communication system according to the first aspect of the present invention, an optical signal including the position information from the roadside device (beacon) side is provided instead of providing an arithmetic unit or the like for estimating the position where the beacon is present on the onboard side. Is transmitted, and the vehicle-mounted device detects the position information to very easily specify the position of the on-road transceiver of the on-road device.

In the road-to-vehicle communication system according to claim 2,
The direction of the vehicle-mounted transceiver of the vehicle-mounted device is controlled in the direction of the on-road transceiver thus detected. This allows
The optical signal from the beacon can be reliably received, and the optical signal can be accurately transmitted to the beacon.

In the road-to-vehicle communication system according to claim 3,
The intensity of the optical signal to the roadside equipment is changed according to the position of the roadside transceiver thus detected. That is, as the distance to the on-road transceiver increases, the intensity of the optical signal to be transmitted is increased, and the vehicle information is reliably transmitted to the on-road device.

In the road-to-vehicle communication system according to claim 4,
The roadside device includes not only its position information but also the position information of the next roadside device installed on the route of the vehicle with which it is communicating, in the optical signal, and provides it to the vehicle-mounted device. As a result, the in-vehicle device can detect the existing position of the next on-road device in advance, and the direction and strength of the on-vehicle transceiver can be set in advance until the position of the next on-road device. Communication with the machine.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a road-vehicle communication system according to the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of the system. The light emitting unit 10
a, a light receiving unit 10b, and a control unit 10c that controls them. The light emitting section 10a and the light receiving section 10b are each composed of a plurality of light emitting elements such as LEDs and light receiving elements,
Sends and receives near infrared light. The data to be transmitted is sent from the center station (not shown) to the control unit 10c, and the control unit 10c
Then, this data is supplied to the light emitting unit 10a and is transmitted on the road as an optical signal. On the other hand, the light receiving unit 10b receives an optical signal transmitted from an in-vehicle device described later and outputs it to the control unit 10c. On the other hand, the in-vehicle device has a light receiving portion 12a, a light emitting portion 12b,
The control unit 12c is provided, and further, a beam direction changing unit 12d for controlling the light receiving unit 12a and the light emitting unit 12b based on a control signal from the control unit 12c, and an output changing unit 12e are provided. The light receiving section 12a and the light emitting section 12b are composed of a plurality of light receiving elements and light emitting elements, and the optical signal of the near infrared light received by the light receiving section 12a is output to the control section 12c.
The control unit 12c detects the position information of the road device included in the received optical signal, and outputs a control signal to the beam direction changing unit 12d and the output changing unit 12e based on the position information.
Based on this control signal, the beam direction changing unit 12d directs the light receiving unit 12a and the light emitting unit 12b toward the roadside device, and the output changing unit 12e changes the intensity of the optical signal output from the light emitting unit 12b according to the position of the roadside device. Control.

FIG. 2 shows a beam direction changing portion 12d of the vehicle-mounted device.
An example is shown. Gears are provided at the swing centers of the light receiving portion 12a and the light emitting portion 12b, and the gear of the pulse motor 16 is arranged so as to mesh with the gears. Control unit 12c
The pulse motor rotates left and right by a predetermined amount in response to a control signal from the light receiving unit 12a and the light emitting unit 12b, which swings left and right by a predetermined amount, in a predetermined direction, that is, the light emitting unit 1 of the roadside machine.
0a, facing the direction of the light receiving portion 10b.

On the other hand, FIG. 3 shows the output variable section 12e of the vehicle-mounted device.
An example is shown. The output port P1 of the control unit 18,
Resistors R1, R2 and R3 are connected to P2 and P3, respectively. Then, the control unit 18 controls the H and L of each output port.
By controlling the ON / OFF combination of the FETs, the drive current to the light emitting element is controlled by the control of the.
The intensity of the optical signal from is controlled. In addition, each resistor R1,
The values of R2 and R3 may be different from each other so that the intensity of the optical signal can be controlled in more steps.

The configuration of this embodiment is as described above, but the characteristic of this embodiment is that the optical signal transmitted from the light emitting section 12a of the road device includes the position information of the road device. is there. FIG. 4 shows an example of a data format of an optical signal transmitted from the light emitting unit 12a of the roadside device.
The optical signal data includes a control unit, a header, and actual data, but the optical signal in the present embodiment is characterized in that part of the actual data includes its position information as beacon information. The beacon position information includes the number of communication lanes and the installation position as shown in FIG. 4, and the installation position includes the distance to the lane and the elevation angle for each lane covered by the beacon. It should be noted that FIG. 4 shows a case of two lanes, which includes position information of the distance A and the elevation angle A for the lane A, and the distance B and the elevation angle B for the lane B.
Location information is included. Since the optical signal transmitted from the light emitting unit 10a of the beacon includes the position information of the beacon in this way, the in-vehicle device side can easily identify the position of the beacon only by detecting the position information. The light receiving portion 12a and the light emitting portion 12 can be formed based on this position information.
The optical signal can be reliably received by directing b to a predetermined direction, and the optical signal can be reliably transmitted by changing the intensity of the optical signal to be transmitted according to the distance to the beacon.

The communication process of this embodiment will be described in more detail below with reference to the flowchart of FIG.

First, the control unit 12c determines whether or not the demodulation level of the optical signal received by the light receiving unit 12a is not less than a specified value (S101). When the vehicle enters the communication area of the roadside device, an optical signal of sufficient intensity is incident on a predetermined position of the vehicle, for example, the light receiving unit 12a of the vehicle-mounted device installed on the dashboard. That is all.
In this case, it is determined that the user has entered the area where communication is possible, and communication is started (S102). That is, the control unit 12c recognizes the traveling lane in which the vehicle is currently traveling based on the optical signal from the beacon, and further identifies the beacon based on the position information included in the optical signal from the roadside device received by the light receiving unit 12a. Recognize relative position, that is, beacon direction and distance. In this embodiment, the distance means the distance between the beacon and the center of the communication area, and the elevation angle means the angle at which the beacon is desired from the center of the communication area. After the position of the beacon is specified, the control unit 12c determines the minimum output level required for communication, and also determines the optimum beam direction for communication (S104). The power level can be determined in proportion to the distance to the beacon, and the beam direction can use the elevation angle of the beacon. After the minimum output level and the beam direction are determined, the control unit 12c outputs a control signal to the beam direction changing unit 12d and the output changing unit 12e,
The output of the optical signal to be transmitted and the beam direction are adjusted (S
105). After the output and the beam direction have been adjusted in this way, the light emitting unit 12b of the vehicle-mounted device transmits predetermined information as an optical signal to the light receiving unit 12b of the beacon based on the data from the control unit 12c. The light receiving unit 12a receives the optical signal transmitted from the light emitting unit 10a. At this time, since the output is optimized based on the distance to the beacon, it is possible to reduce the light emission power consumption and prolong the life of the light emitting element, and since the light receiving unit 12a is directed toward the beacon, The demodulation level is increased, the S / N is improved, and high quality communication can be performed.
When the desired communication is performed and the vehicle escapes from the communication area of the beacon, the demodulation level of the optical signal received by the light receiving unit 12a becomes equal to or lower than the specified value, and the communication with the beacon ends (S106, S107). After the communication is completed, the output and the beam direction are initialized, that is, the output is set to the maximum value, and the beam direction is set above the vehicle traveling direction (for example, about 40 degrees in elevation angle) to prepare for the next communication ( S10
8).

As described above, in the present embodiment, the beam direction and the output of the vehicle-mounted device are adjusted based on the position information of the beacon included in the optical signal from the beacon, so that the light receiving level is increased and the S / N ratio is high. Can communicate, and also
It is also possible to suppress an unnecessary increase in the amount of light emission to save power and reduce the number of light receiving and emitting elements.

In this embodiment, the position information of the beacon is transmitted as the position information from the beacon,
It is also possible to simultaneously transmit the position information of the next beacon on the traveling route of the vehicle recognized based on the optical signal from the vehicle-mounted device. FIG. 5 shows an example of the data format of beacon information in such a case. In FIG. 4, the position information of the beacon includes the number of communication lanes and the installation position of the beacon, but in FIG. 5, not only the position information of the beacon as beacon information but also the next installed position on the vehicle route. Includes the number of communication lanes and installation location information for the beacon. By detecting not only the position information of the current beacon but also the position information of the next beacon, the control unit 12c of the vehicle-mounted device can control the output and the beam direction in advance for the next communication. That is,
In the communication processing of the above-described embodiment, the output and the beam direction are initialized when the communication is completed once (see S108), but once the position information of the next beacon is recognized in advance, the communication is performed once. When the communication of 1 is completed, the output and the beam direction can be preset based on the position information of the next beacon. As a result, the time required for control from the initial value to the optimum value is shortened, and communication with the beacon can be performed more quickly and reliably.

Depending on the case, it is possible to include only the beacon position information in the optical signal next time, which is effective when the vehicle is traveling at high speed.

[0024]

As described above, according to the road-to-vehicle communication system of claims 1 to 4, the amount of light emission at the time of transmitting an optical signal is optimized to suppress unnecessary increase, and the life of the light emitter is long. It is possible to improve the S / N ratio of the received signal, and it is possible to perform high-quality road-to-vehicle communication.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a beam direction changing unit in the embodiment.

FIG. 3 is a configuration diagram of an output variable unit in the embodiment.

FIG. 4 is a data format diagram of an optical signal from a beacon in the embodiment.

FIG. 5 is a data format diagram of an optical signal from a beacon according to another embodiment of the present invention.

FIG. 6 is a processing flowchart in the embodiment of the present invention.

[Explanation of symbols]

 10a Light emitting part of road equipment 10b Light receiving part of road equipment 10c Control part of road equipment 12a Light receiving part of onboard equipment 12b Light emitting part of onboard equipment 12c Control part of onboard equipment 12d Beam direction changing part 12e Output changing part 16 Pulse motor 18 Control Department

Claims (4)

[Claims] 1. A road-to-vehicle communication system for performing optical communication between a roadside device including a roadside transceiver and an in-vehicle device including an in-vehicle transceiver, wherein the roadside device transmits an optical signal including position information of the roadside transceiver. The on-vehicle device includes a position specifying unit that receives the optical signal and specifies the position of the road transceiver from the position information included in the optical signal. 2. The road-vehicle communication system according to claim 1, wherein the vehicle-mounted device further includes direction control means for controlling the direction of the vehicle-mounted transceiver according to the position specified by the position specifying means. Road-to-vehicle communication system characterized by. 3. The in-vehicle device according to claim 1 or 2, further controlling the intensity of an optical signal transmitted from the in-vehicle transceiver in accordance with the distance to the position specified by the position specifying means. A vehicle-to-vehicle communication system, comprising: 4. Claim 1 or claim 2 or claim 3.
In the road-vehicle communication system described above, the road-vehicle communication system further transmits an optical signal including position information of a next road-vehicle installed on a vehicle travel route.