JP2017092879A - Optical beacon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reflection light of downlink light from disturbing uplink communication at another lane.SOLUTION: An optical beacon according to one aspect of the present invention performs radio communication with an on-vehicle device of a travelling vehicle by using an optical signal. The optical beacon comprises: beacon heads installed on lanes included in a road; and a beacon controller for causing each of the beacon heads to transmit downlink light. The amount of downlink arrival light at a reference position located outside the lanes at a reference plane at a prescribed height from a road surface is set to a prescribed value or less.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an optical beacon that performs wireless communication using an optical signal with an in-vehicle device of a traveling vehicle.

As a traffic information service using a road-to-vehicle communication system, so-called VICS (Vehicle Information and Communication System: registered trademark of Road Traffic Information Communication System Center) using optical beacons, radio beacons or FM multiplex broadcasting has already been developed. ing.
Among these, the optical beacon employs optical communication using near infrared rays as a communication medium, and is capable of bidirectional communication with the in-vehicle device. Specifically, uplink information including travel time information between beacons held by the vehicle is transmitted from the in-vehicle device to the infrastructure-side optical beacon.

Conversely, downlink information including traffic jam information, section travel time information, event regulation information, lane notification information, and the like is transmitted from the optical beacon to the in-vehicle device (see, for example, Patent Document 1).
For this reason, the optical beacon includes a light projecting / receiving device (hereinafter also referred to as a “beacon head”) that projects and receives an optical signal with the vehicle-mounted device for each lane. In each beacon head casing, there is mounted a transmission / reception unit for optical communication having a light emitting element for transmitting downlink light toward the road and a light receiving element for receiving uplink light transmitted by the vehicle-mounted device. .

JP 2005-268925 A

In an optical beacon in which a beacon head is installed for each of a plurality of lanes, reflected light of downlink light from a beacon head of a certain lane (hereinafter referred to as “first lane”) is reflected in another lane (hereinafter referred to as “second lane”). May reach the beacon head.
In this case, the beacon head in the second lane cannot receive the uplink light transmitted by the vehicle traveling in the second lane due to the influence of the reflected light, and uplink communication in the second lane may be hindered.

In particular, in the case of a “high-speed optical beacon” that has two types of uplink optical transmission rates, the high-speed uplink frame transmission rate (256 kbit / s) is the low-speed uplink frame transmission rate (64 kbit / s). Compared to the transmission speed of the downlink light (1024 kbit / s).
For this reason, the high-speed uplink frame is more easily affected by the reflected light of the downlink light from other lanes than the low-speed uplink frame, and the above-described problem becomes even more remarkable.

  In view of the conventional problems, an object of the present invention is to suppress the reflected light of downlink light from hindering uplink communication in other lanes.

  (1) An optical beacon according to an aspect of the present invention is an optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal, the beacon head installed on a lane included in a road, A beacon controller that transmits a downlink light to a beacon head, and the amount of light reaching the downlink at a reference position located outside the lane on a reference surface at a predetermined height from the road surface is less than or equal to a predetermined value. Is set.

  (2) An optical beacon according to another aspect of the present invention is an optical beacon that performs wireless communication using an optical signal with an on-vehicle device of a running vehicle, and a beacon head installed on a lane included in a road; A beacon controller that transmits downlink light to the beacon head, wherein the beacon head has a reference light amount at a downlink reaching light amount at a predetermined position in a vehicle traveling direction on a reference surface having a predetermined height from the road surface. The distance in the road width direction from the center line passing through is set to be a predetermined distance or less.

  (3) An optical beacon according to another aspect of the present invention is an optical beacon that performs wireless communication using an optical signal with an on-vehicle device of a traveling vehicle, and a beacon head installed on a lane included in a road; A beacon controller that transmits downlink light to the beacon head, wherein the beacon head has a reference light amount at a downlink reaching light amount at a predetermined position in a vehicle traveling direction on a reference surface having a predetermined height from the road surface. The angle in the road width direction with respect to the center line passing through is set to a predetermined angle or less.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the reflected light of downlink light inhibits uplink communication in another lane.

It is a block diagram which shows schematic structure of a road-vehicle communication system. It is the top view of the road which looked at the installation part of an optical beacon from the top. It is a side view of the road which shows the communication area | region and incident area of an optical beacon. It is a frame block diagram of an uplink frame (uplink information). It is a frame block diagram of a downlink frame (downlink information). It is a figure which shows the road width direction range of the downlink area | region of the conventional optical beacon. It is a figure which shows the road width direction range of the downlink area | region of the optical beacon which concerns on this embodiment. It is a top view of the road which shows the specific example of the reference position which deviated from the lane. It is a figure which shows the specific example 1 of the restriction | limiting structure of the light emission range. It is a figure which shows the specific example 2 of the restriction | limiting structure of the light emission range. It is a figure which shows the specific example 3 of the restriction | limiting structure of the light emission range. It is a figure which shows the specific example 4 of the restriction | limiting structure of the light emission range.

<Outline of Embodiment of the Present Invention>
Hereinafter, an outline of embodiments of the present invention will be listed and described.
(1) The optical beacon according to the present embodiment is an optical beacon that performs wireless communication using an optical signal with an in-vehicle device of a running vehicle, and a beacon head installed on a lane included in a road, and the beacon head A beacon controller that transmits downlink light, and a downlink arrival light amount at a reference position located outside the lane on a reference plane having a predetermined height from a road surface is set to a predetermined value or less. Yes.

According to the optical beacon of the present embodiment, the amount of downlink light reaching the second lane from the beacon head of the first lane is determined by defining the above “predetermined value” regarding the amount of light reaching the downlink to an appropriate value. Can be reduced. That is, the irradiation range of the beacon head in the road width direction can be limited.
For this reason, the reflected light of the downlink light in the first lane does not easily reach the beacon head in the second lane, and the uplink light (particularly the high-speed uplink frame) transmitted by the vehicle traveling in the second lane is The possibility that the beacon head in the lane cannot be received can be reduced.

  (2) The optical beacon according to the present embodiment viewed from another viewpoint is an optical beacon that performs wireless communication with an in-vehicle device of a traveling vehicle using an optical signal, and is installed on a lane included in a road. And a beacon controller that causes the beacon head to transmit downlink light, and at a predetermined position in a vehicle traveling direction on a reference plane at a predetermined height from the road surface, the amount of light reaching the downlink is a reference value. The distance in the road width direction from the center line passing through the beacon head is set to be a predetermined distance or less.

According to the optical beacon of the present embodiment, the amount of downlink light reaching the second lane from the beacon head of the first lane by defining the “predetermined distance” related to the distance in the road width direction to an appropriate value. Can be reduced. That is, the irradiation range of the beacon head in the road width direction can be limited.
For this reason, the reflected light of the downlink light in the first lane does not easily reach the beacon head in the second lane, and the uplink light (particularly the high-speed uplink frame) transmitted by the vehicle traveling in the second lane is The possibility that the beacon head in the lane cannot be received can be reduced.

  (3) The optical beacon of this embodiment viewed from another viewpoint is an optical beacon that performs wireless communication with an on-vehicle device of a running vehicle using an optical signal, and is installed on a lane included in a road. And a beacon controller that causes the beacon head to transmit downlink light, and at a predetermined position in a vehicle traveling direction on a reference plane at a predetermined height from the road surface, the amount of light reaching the downlink is a reference value. The angle in the road width direction with respect to the center line passing through the beacon head is set to a predetermined angle or less.

According to the optical beacon of the present embodiment, the amount of downlink light reaching the second lane from the beacon head of the first lane by defining the “predetermined angle” related to the angle in the road width direction to an appropriate value. Can be reduced. That is, the irradiation range of the beacon head in the road width direction can be limited.
For this reason, the reflected light of the downlink light in the first lane does not easily reach the beacon head in the second lane, and the uplink light (particularly the high-speed uplink frame) transmitted by the vehicle traveling in the second lane is The possibility that the beacon head in the lane cannot be received can be reduced.

<Details of Embodiment of the Present Invention>
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the present embodiment, an uplink frame transmitted from the in-vehicle device 2 toward the optical beacon 4 may be referred to as “uplink information” or “uplink signal”.
In addition, a downlink frame transmitted from the optical beacon 4 toward the in-vehicle device 2 may be referred to as “downlink information” or “downlink signal”.

[Overall system configuration]
FIG. 1 is a block diagram showing a schematic configuration of a road-vehicle communication system according to the present embodiment. FIG. 2 is a plan view of the road R when the installation portion of the optical beacon 4 of this embodiment is viewed from above.
As shown in FIG. 1, the road-to-vehicle communication system of this embodiment includes an infrastructure-side traffic control system 1 and an in-vehicle device 2 mounted on a vehicle 20 (see FIG. 3) traveling on a road R. .

The traffic control system 1 includes a central device 3 provided in a traffic control room or the like, and a large number of optical beacons (optical vehicle detectors) 4 installed at various locations on the road R. The optical beacon 4 can perform wireless communication with the in-vehicle device 2 by optical communication using near infrared as a communication medium.
The optical beacon 4 includes a beacon controller (communication controller) 7 that performs communication control and the like, and a plurality (four in the example of FIG. 1) of beacon heads (transmit / receive) connected to the sensor interface of the beacon controller 7. 8).

The beacon controller 7 is connected to a communication unit 6 on the infrastructure side, and the communication unit 6 is connected to the central apparatus 3 by a communication line 5 such as a telephone line.
The communication unit 6 can be configured by, for example, a traffic signal controller that controls the color of a signal lamp, an information relay device that performs a relay process of traffic information on the infrastructure side, and the like.

The optical beacon 4 of this embodiment employs a full-duplex communication method. That is, the beacon controller 7 simultaneously performs transmission control in the downlink direction for the light emitting unit 13 for optical communication and reception control in the uplink direction for the light receiving unit 14 for optical communication.
On the other hand, the in-vehicle device 2 of the present embodiment employs a half-duplex communication method. That is, the below-described vehicle-mounted controller 21 (see FIG. 3) does not simultaneously perform uplink direction transmission control for the optical transmission unit 23 and downlink direction reception control for the optical reception unit 24.

[Overall configuration of optical beacon]
The beacon head 8 of the optical beacon 4 includes a transmission / reception unit 11 (optical transmission / reception unit) for optical communication and a sensor unit 12 for vehicle detection in a housing 31 (see FIGS. 1 and 3).
As described above, in the optical beacon 4 of the present embodiment, the optical communication function and the vehicle detection function are obtained by incorporating the units 11 and 12 for optical communication and vehicle detection into the casing 31 of one beacon head 8, respectively. It has a structure with both.

The optical communication transceiver unit 11 is an optical transceiver that wirelessly transmits and receives optical signals to and from the in-vehicle device 2.
As shown in FIG. 1, the transmission / reception unit 11 receives a light emitting unit 13 for optical communication that transmits a downlink light DO (see FIG. 3) and an uplink light UO (see FIG. 3) and converts them into electrical signals. And a light receiving unit 14 for optical communication.

A light emitting unit 13 for optical communication (hereinafter also referred to as “communication light emitting unit 13”) includes a transmission circuit that converts a downstream frame transmitted from the beacon controller 7 into a serial transmission signal having a predetermined transmission rate; A light emitting element made of a light emitting diode (LED) that converts the output transmission signal into an optical signal in a downlink direction.
The light emitting element of the communication light emitting unit 13 sends the downlink light DO, which is a near infrared light signal, obliquely downward toward the upstream side.

The light receiving unit 14 for optical communication (hereinafter also referred to as “communication light receiving unit 14”) amplifies a light receiving element such as a photodiode (PD) and an electric signal output from the light receiving element. A receiving circuit for generating a digital signal.
The light receiving element of the communication light receiving unit 14 receives the uplink light UO, which is a near-infrared optical signal transmitted by the vehicle-mounted device 2 before the beacon head 8, and converts it into an electrical signal. The reception circuit of the communication light receiving unit 14 sends a digital signal generated from the converted electrical signal to the beacon controller 7.

The sensor unit 12 is a light detection sensor for detecting the presence of the vehicle 20 passing almost directly below the beacon head 8 without contact.
As shown in FIG. 1, the sensor unit 12 includes a vehicle sensing light emitting unit 15 that transmits incident light IO (see FIG. 3), and a vehicle that receives reflected light RO (see FIG. 3) and converts it into an electrical signal. And a light receiving unit 16 for sensing.

The vehicle-sensing light-emitting unit 15 (hereinafter also referred to as “sensing light-emitting unit 15”) transmits incident light IO, which is an optical pulse signal having a predetermined cycle, downward.
The vehicle sensing light receiving unit 16 (hereinafter also referred to as “sensing sensing light receiving unit 16”) receives the reflected light RO of the incident light IO on the road R and the vehicle 20, and uses the received reflected light RO as an electrical signal. Convert and send to the beacon controller 7.

The beacon controller 7 includes a computer device having a signal processing unit, a CPU, a memory, and the like, and has a function as a communication control unit that performs communication with the central device 3 and communication between the in-vehicle device 2 and the vehicle according to a predetermined communication interface standard. And a function as a sensing control unit of the vehicle 20.
The beacon controller 7 stores a computer program for communication control and sensing control in a storage device (not shown), and the CPU reads out and executes the program so that the CPU performs the communication control. Functions as a control unit and a sensing control unit.

For example, the beacon controller 7 may include a downlink signal (first downlink frame) including lane notification information in which an identification value of a vehicle ID (hereinafter also referred to as “ID value”) is not stored, or predetermined provision information. Is transmitted to the communication light-emitting unit 13 at a predetermined cycle.
The beacon controller 7 continues to transmit the downlink signal, and receives the uplink signal (uplink frame) including the ID value that the vehicle-mounted device 2 will transmit when receiving the downlink signal. Judgment is made.

  When the beacon controller 7 detects the reception of the uplink signal by the communication light receiving unit 14, the lane notification information storing the ID value and the lane number value extracted from the uplink signal, the provision information for the vehicle 20, and And one or a plurality of downlink signals (second downlink frames) including the generated information are transmitted to the communication light emitting unit 13 for a predetermined time (for example, 250 to 350 ms).

Then, when the predetermined time elapses, the beacon controller 7 restores the content of the provision information included in the downlink signal and waits for reception of the uplink signal from the in-vehicle device 2 of the vehicle 20 that comes next. .
Note that the beacon controller 7 transfers information included in the uplink signal, such as probe data including a travel locus such as the position and time of the vehicle 20, to the central device 3.

The beacon controller 7 always sends the incident light IO of a predetermined wavelength to the sensing light emitting unit 15 at a constant intensity and pulse period, and whether the received light intensity of the reflected light RO received by the sensing light receiving unit 16 is equal to or greater than a threshold value. The presence of the vehicle 20 is sensed depending on whether or not.
That is, the beacon controller 7 generates a sensing signal of the vehicle 20 and transmits the sensing signal to the central device 3 when the light receiving intensity of the reflected light RO that is equal to or greater than the threshold value is detected in the sensing light receiving unit 16. This threshold value is not limited to a fixed value, and may vary depending on, for example, a follow-up process according to the received light intensity of the reflected light RO.

[Optical beacon installation status]
As shown in FIG. 2, the optical beacon 4 of the present embodiment is installed on a road R having a plurality (four in the illustrated example) of lanes R1 to R4 in the same direction.
The optical beacon 4 includes a plurality of the beacon heads 8 provided corresponding to the respective lanes R1 to R4, and one beacon controller 7 that is a communication control unit that collectively controls these beacon heads 8. Prepare.

The beacon controller 7 is installed on a support column 17 erected on the left side of the road R. Each beacon head 8 is attached to an erection bar (beam member) 18 that is laid horizontally on the road R side from the column 17 and is disposed immediately above the center position of each lane R1 to R4.
The communication light emitting unit 13 of the beacon head 8 emits the downlink light DO toward the upstream side in the vehicle traveling direction from directly below the own device. Thereby, the communication area A for performing road-to-vehicle communication with the vehicle-mounted device 2 is set on the upstream side of the beacon head 8.

  The sensing light emitting unit 15 of the beacon head 8 emits the incident light IO almost directly below the own device. As a result, the incident area B, which is the sensing area of the vehicle 20 passing through the predetermined lanes R1 to R4 on the road R, is set almost directly below the beacon head 8.

[Communication area and incident area of optical beacons]
FIG. 3 is a side view of the road R showing the communication area A and the incident area B of the optical beacon 4.
As shown in FIG. 3, the communication area A of the transmission / reception unit 11 includes a downlink area DA (solid hatched portion) that is a receivable range of the downlink light DO by the in-vehicle device 2 and an uplink light UO by the beacon head 8. And an uplink area UA (broken line hatched portion) which is a light receiving range.

According to the UTMS (Universal Traffic Management Systems) Association “Optical Vehicle Detector Near-Infrared Interface Standard Version 2” (hereinafter referred to as “Old Interface Standard”) established on August 3, 2001, each area DA, UA The standard values of the upstream / downstream end positions are as follows.
Downstream area DA downstream end position a0: +1.3 m
Downstream end position b0 of the uplink area UA: a0 + 2.1 m (= 3.4 m)
Upstream end position c0 of both areas DA and UA: b0 + 1.6 m (= 5.0 m)

In the “Advanced Optical Beacon Near-Infrared Interface Standard Version 3” (hereinafter referred to as “New Interface Standard”) of the UTMS Association, which was formulated on January 5, 2015, the standard value of the upstream end position of each area DA, UA ( For general roads):
Downstream area DA downstream end position a0: +0.70 m
Downstream end position b0 of the uplink area UA: a0 + 2.70 m (= 3.40 m)
Upstream end position c0 of both areas DA and UA: b0 + 2.64 m (= 6.04 m)
The standard values of the positions a0 to c0 are values when the upstream direction is a positive number from the position immediately below the light emitter / receiver 8 (origin O) on the reference plane having a height H of 1.0 m from the road surface. .

In the old interface standard, the transmission rate of the uplink optical UO transmitted by the vehicle-mounted device 2 is only 64 kbit / s, and the transmission rate of the downlink optical DO received by the vehicle-mounted device 2 is only 1024 kbit / s.
On the other hand, in the new interface standard, the transmission speed of the downlink optical DO is the same as the conventional one, but the transmission speed of the uplink optical UO is two types of high and low (low speed is 64 kbit / s and high speed is 256 kbit / s. s).

Therefore, the optical beacon 4 according to the new interface standard is a multi-rate compatible optical beacon (hereinafter referred to as “new optical beacon”) that can perform conventional low-speed uplink reception and new high-speed uplink reception.
The in-vehicle device 2 conforming to the new interface standard is a multi-rate in-vehicle device (hereinafter referred to as “new in-vehicle device”) that can perform conventional low-speed uplink transmission and new high-speed uplink transmission.

The optical beacon 4 and the in-vehicle device 2 according to the present embodiment may conform to any of the old interface standard and the new interface standard described above.
However, in the following description, it is assumed that the optical beacon 4 of the present embodiment is a new optical beacon, and the in-vehicle device 2 of the present embodiment is a new in-vehicle device.

The incident area B of the sensor unit 12 is an irradiation range of the incident light IO on which the sensing light emitting unit 15 enters the road R.
The center of the incident area B in the road width direction is at a position substantially equal to the center of the lanes R1 to R4 corresponding to the beacon head 8 in the road width direction. The emission direction V1 of the incident light IO is normally directed upstream (plus side) by a predetermined angle α (for example, 4.5 °) with respect to the vertical direction, but is downstream by a predetermined angle with respect to the vertical direction. It may be directed to the side (minus side).

[Configuration of in-vehicle device]
As shown in FIG. 3, the in-vehicle device 2 of the present embodiment includes an in-vehicle controller (communication control unit) 21 and an in-vehicle head (optical transmission / reception unit) 22. An optical transmitter 23 and an optical receiver 24 are accommodated in the in-vehicle head 22.
The optical transmitter 23 has a light emitting element that emits an uplink light UO (uplink direction optical signal) made of near infrared rays, and the optical receiver 24 has a downlink light UO (downlink direction made of near infrared rays). A light receiving element for receiving an optical signal).

The optical transmission unit 23 is a light emitting circuit that converts an upstream frame output from the in-vehicle controller 21 into a serial transmission signal having a predetermined transmission rate, and converts the output transmission signal into an optical signal in the uplink direction. And a light emitting element made of a diode or the like.
The optical receiver 24 includes a light receiving element such as a photodiode that photoelectrically converts an optical signal in the downlink direction and outputs an electric signal, and a receiving circuit that amplifies the output electric signal and generates a digital received signal. Have

The in-vehicle controller 21 includes a computer device having a signal processing unit, a CPU, a memory, and the like, and has a function as a communication control unit that performs road-vehicle communication with the optical beacon 4.
The in-vehicle controller 21 stores a computer program for communication control in a storage device (not shown), and the CPU reads and executes the program, so that the CPU functions as the communication control unit. To do.

The in-vehicle controller 21 generates traveling data of the host vehicle (for example, probe information that is traveling locus data in which passing positions and passing times are arranged in time series) as uplink data, and uploads it to the optical transmitter 23. It also has a function to transmit a link.
In this case, if the uplink speed is increased as in the new interface standard, more probe information (longer road sections that record the travel trajectory, higher recording density of passing positions and passing times in the same road section) Information can be transmitted.

The in-vehicle controller 21 of this embodiment may have a circuit configuration in which a simple control unit including an ASIC (Application Specific Integrated Circuit) is provided separately from the main body control unit including the CPU.
For example, when the optical receiving unit 24 receives any downlink frame, the simple control unit transmits only one uplink frame (conventional uplink frame having a transmission rate of 64 kbit / s) including the vehicle ID of the host vehicle. The unit 23 has a function of causing uplink transmission.

As shown in FIG. 3, a navigation device 25 is mounted on the vehicle 20. The navigation device 25 includes a route search unit that searches for an optimal route when traveling to a destination, an operation unit for a passenger to input to the route search unit, and an optimal route that is a calculation result using an image or voice. A display and a speaker for guiding the user.
In general, the route search unit calculates a minimum cost route that minimizes the link cost by a specific route search logic. As the route search logic, for example, the Dijkstra method or the potential method is used.

The navigation device 25 has a time synchronization function for acquiring the current time from the GPS signal, a position detection function for measuring the current position (latitude, longitude, and altitude) of the host vehicle from the GPS signal, and an azimuth and angular velocity of the host vehicle by the direction sensor. It has an orientation detection function that measures
The navigation device 25 also includes a storage device (not shown) in which road map data is stored. The road map data is used to map match the position information of the host vehicle during the search process by the route search unit.

The in-vehicle controller 21 outputs the information to the navigation device 25 when the information regarding the traffic restriction and the information useful for navigation (for example, “simple graphic information” of the road) are included in the downlink signal. .
For example, when the navigation device 25 acquires simple graphic information from the in-vehicle controller 21, the navigation device 25 displays the graphic information on the display. Thereby, the passenger of the vehicle 20 can visually recognize a simple image or the like indicating road traffic information in the vicinity of the intersection on the downstream side of the beacon head 8 in advance.

[Frame structure of upstream frame]
FIG. 4 is a frame configuration diagram of an uplink frame (uplink information).
As shown in FIG. 4, in the upstream frame storage area, in order from the beginning, a transmission control unit for synchronization (hereinafter referred to as “synchronizing unit”) for synchronizing with the receiving side, a header unit, and an actual data unit. And a CRC (Cyclic Redundancy Check) transmission control unit (hereinafter referred to as “CRC unit”).

In the upstream frame, 1 byte is assigned to the synchronization part, 10 bytes are assigned to the header part, 59 bytes at maximum are assigned to the real data part, and 4 bytes (1 byte idle part + 2 bytes CRC + 1 byte) are assigned to the CRC part. Of the last synchronization part).
The header portion of the upstream frame includes storage areas such as “number of subsystem key information”, “vehicle ID”, “vehicle equipment type”, “information type”, and “last frame flag”.

In the “number of subsystem key information” (hereinafter sometimes abbreviated as “number of information”), the number of “subsystem key information” stored in order from the top of the actual data portion is stored.
That is, when the number of information is zero, “subsystem key information” is not included in the actual data portion, and when the number of information is “1”, one “subsystem key information” is included in the actual data portion. When the number of information is “n”, n “subsystem key information” is included in the actual data part.

The above-mentioned “subsystem key information” indicates that the optical beacon 4 is a downlink of a public vehicle priority system (PTPS), a vehicle operation management system (MOCS), a field express support system (FAST), and a safe driving support system (DSSS). This is key information for selecting additional information.
The in-vehicle device 2 determines the contents of “subsystem key information” and “subsystem key information” according to which system of the UTMS standard the host vehicle is compatible with.

For example, the in-vehicle device 2 sets the value of the “number of subsystem key information” in the header part to “1” when the host vehicle corresponds to one system of the UTMS standard, and follows the standard of the one system. The “subsystem key information (1)” of the contents is stored in the actual data part.
In addition, when the host vehicle is compatible with two systems of the UTMS standard, the in-vehicle device 2 sets the value of the “number of subsystem key information” in the header part to “2”, and sets the standard of the two systems respectively. The “subsystem key information (1)” and “subsystem key information (2)” having the contents are stored in the actual data part.

  The data format of the “subsystem key information” is different depending on the standard of each system, so the details are omitted. For example, in the case of a safe driving support system (DSSS), the brake state, the turn signal state, the hazard state, Information such as vehicle speed, traveling direction, acceleration / deceleration, and accelerator pedal position is included.

On the other hand, the optical beacon 4 determines which system included in the in-vehicle device 2 is included in the UTMS standard according to the type of “subsystem key information” included in the uplink information, and conforms to the standard of the system. The provided information is stored in the downlink frame and transmitted in the downlink. This provided information is called “special information” in the standard.
In this way, the optical beacon 4 determines the type of “special information” to be included in the downlink information after uplink reception based on the type of “subsystem key information”.

“Vehicle ID” is an area for storing a vehicle ID identification value (which may be a numerical value or a symbol) generated by the vehicle-mounted device 2 itself or automatically generated by the optical beacon 4 and notified to the vehicle-mounted device 2. . The in-vehicle device 2 stores the value of the vehicle ID stored at the time of uplink transmission in the vehicle ID of the header portion of the uplink frame.
“In-vehicle device type” is an area in which the type of the in-vehicle device 2 is stored. “Information type” is an area for storing the type of uplink information. In the new interface standard, the values of these areas indicate whether the uplink transmission subject is new or old, and whether the uplink information is high speed or low speed.

Specifically, when transmitting a low-speed uplink frame, the in-vehicle device 2 stores a predetermined value (for example, “6”) indicating the new in-vehicle device in the “in-vehicle device type” and the predetermined in the “information type”. A value (for example, “1”) is stored.
Further, when transmitting the high-speed uplink frame, the in-vehicle device 2 stores a predetermined value (for example, “6”) indicating the new in-vehicle device in the “in-vehicle device type” and a predetermined value (for example, in the “information type”). , “4”).

Therefore, the optical beacon 4 can be determined as a low-speed frame from the new in-vehicle device when the in-vehicle device type value of the received upstream frame is “6” and the information type value is “1”. When the value of the in-vehicle device type of the upstream frame is “6” and the value of the information type is “4”, it can be determined that the high-speed frame is from the new in-vehicle device.
In the case of an old vehicle-mounted device, the value of the vehicle-mounted device type is set to a value other than “6”. Therefore, when the optical beacon 4 receives an uplink frame having a value of “vehicle-mounted device type” other than “6”, It can be determined that the communication partner is an old vehicle-mounted device that does not support high-speed uplink transmission.

The “last frame flag” is a storage area for indicating which of the uplink frames is the final frame when the in-vehicle device (which may be new or old) transmits an uplink frame group including a plurality of uplink frames. It is.
That is, the in-vehicle device 2 stores a predetermined flag value (for example, “1”) only in the “final frame flag” of the last frame among the plurality of uplink frames constituting the uplink frame group, and other uplink frames Does not store the flag value.

[Frame structure of downstream frame]
FIG. 5 is a frame configuration diagram of a downlink frame (downlink information).
As shown in FIG. 5, the downlink frame storage area also includes a synchronization part, a header part, an actual data part, and a CRC part in order from the top, as in the case of the frame structure of the upstream frame (FIG. 4). .

In the downstream frame, 1 byte is allocated to the synchronization section, 5 bytes are allocated to the header section, 123 bytes are allocated to the real data section, and 4 bytes are allocated to the CRC section (1 byte idle section + 2 bytes CRC + 1 byte final). Synchronous part) is assigned.
The type of information provided to the in-vehicle device 2 included in the actual data portion of the downstream frame may change before and after the optical beacon 4 receives the upstream frame from the in-vehicle device 2.

That is, the optical beacon 4 can switch the content of the information provided to the in-vehicle device 2 before and after receiving the uplink frame.
Specifically, the optical beacon 4 receives a downlink frame (hereinafter referred to as “first downlink frame”) 2015 that is downlink-transmitted before receiving an uplink frame from the in-vehicle device 2 (before uplink reception). Provision of uplink information in "Advanced Optical Beacon Near-Infrared AMIS Communication Application Standard Version 2" (hereinafter referred to as "Communication Application Standard (Version 2)") formulated by UTMS Association on January 5, It is possible to include information (such as “lane notification information”) that is defined not to be a condition in the actual data part.

  The optical beacon 4 has a communication application standard (version 2) in a downlink frame (hereinafter referred to as “second downlink frame”) transmitted in downlink after receiving the uplink frame from the in-vehicle device 2 (after receiving the uplink). ) In the communication application standard (version 2) as well as information stipulated not to be provided with the provision of uplink information (“lane communication information”, etc.) ("Route signal information" etc.) can also be included in the actual data part.

The optical beacon 4 provides the provision information to the in-vehicle device 2 by one downlink frame when the provision information of the single information type to the in-vehicle device 2 fits in the capacity of the actual data part (123 bytes).
The optical beacon 4 is divided into a plurality of downlink frames (downstream frame groups) when the provision information of the single information type to the in-vehicle device 2 does not fit in the capacity of the actual data part (123 bytes), The provided information is provided to the in-vehicle device 2. Therefore, different information types are not mixed in one downstream frame.

As shown in FIG. 5, examples of the provision information included in the first downlink frame include, for example, “lane notification information” (where the vehicle ID identification value is not stored), “current position information”, and the like. There is. The “lane notification information” is information for notifying the lane number where the vehicle 20 travels, and the “current position information” is the position information (latitude and longitude) of the installation location of the beacon head 8.
The storage area of “lane notification information” includes “vehicle ID”, “lane number”, and “beacon identification flag”. The optical beacon 4 does not store the identification value in the “vehicle ID” in the lane notification information included in the downlink frame before uplink reception.

When the optical beacon 4 receives the upstream frame including the identification value (ID value) of the vehicle ID from the in-vehicle device 2, the optical beacon 4 stores the acquired ID value in the “vehicle ID” of the lane notification information (hereinafter, this downstream frame). Is also referred to as a “turnback frame”), and the generated return frames are downlink transmitted at predetermined intervals.
Therefore, the in-vehicle device 2 can determine communication establishment with the optical beacon 4 based on whether or not the ID value of the host vehicle is included in the received lane notification information of the return frame.

In addition, the optical beacon 4 writes the lane number value corresponding to the beacon head 8 that acquired the uplink information in the “lane number” of the lane notification information included in the return frame.
Therefore, the in-vehicle device 2 can determine which lane the host vehicle is traveling from the lane number value included in the received lane notification information of the return frame.

The “beacon identification flag” is a storage area indicating whether or not the own device supports high-speed uplink reception.
When the optical beacon 4 is a new optical beacon, the optical beacon 4 stores a predetermined flag value (for example, “01”) in the “beacon identification flag” of the downstream frame. Other values (for example, “00”) are stored in the “beacon identification flag” of the downstream frame.

  Accordingly, the in-vehicle device 2 determines whether the optical beacon 4 of the communication partner is a new optical beacon or an old optical beacon based on the value of the “beacon identification flag” included in the “lane notification information” of the downlink frame. Can do.

The downlink frame group that is repeatedly transmitted by the transmission / reception unit 11 of the optical beacon 4 after uplink reception is composed of 1 to 80 downlink frames, and in the case of the old interface standard, the transmission time of the repeated transmission is 250 ms. .
Further, the downlink frame is composed of an arbitrary number of frames corresponding to the amount of data to be transmitted in the downlink direction, and is repeatedly transmitted within the above-described transmittable time range, and the downlink frame transmission period is about 1 ms.

Therefore, for example, when one significant data (provided information) is constituted by three downstream frames, the transmission cycle is about 3 ms, so that the data is about 80 times within a predetermined transmittable time (250 ms). It will be sent repeatedly.
However, in the optical beacon of the new interface standard, the downlink area DA is expanded to the vicinity immediately below the beacon head 8, so that the number of times of repeatedly transmitting a downlink frame group composed of 1 to 80 downlink frames is increased. be able to.

As shown in FIG. 5, examples of the provision information included in the second downlink frame include “route signal information” and “travel speed link information”.
“Route signal information” refers to route signal information at an intersection in the forward direction from the point where the optical beacon 4 is installed. “Travel speed link information” is travel speed information of provided links preset for each optical beacon 4.

[Problems caused by reflected light of downlink light]
FIG. 6 is a diagram illustrating a road width direction range of a downlink area DA of a conventional optical beacon.
As shown in FIG. 6, in each of the old and new interface standards, the road width direction range of the downlink area DA is the center of the lanes R1 to R4 on the reference plane having a predetermined height (H = 1.0 m) from the road surface. At a measurement position P of ± 1.75 m in the left-right direction as the origin, it is defined as a range in which a downlink reaching light amount equal to or greater than a predetermined reference value (= 4.5 μW / cm ² ) is obtained.

  The measurement position P needs to be within the vehicle traveling direction range of the downlink area DA (the range from the downstream end position a0 to the upstream end position c0 in FIG. 3), and is usually the downstream end position of the downlink area DA. Two locations, a0 and upstream end position c0, are employed. Therefore, for example, in the case of the new interface standard, the vehicle traveling direction position of the measurement position P is two locations of 0.70 m and 6.04 m from directly below the head to the upstream side.

For example, as shown in FIG. 6, when the downlink irradiation range of the beacon head 8 in each lane R1, R2 protrudes into the other lanes R2, R1, the reflected light of the downlink light DO from the beacon head 8 in the lane R1 May reach the beacon head 8 in the lane R2.
In this case, the beacon head 8 in the lane R2 cannot receive the uplink light UO transmitted by the vehicle 20 passing through the lane R2 due to the influence of reflected light, and uplink communication in the lane R2 may be hindered.

In particular, among the low-speed uplink frame UL1 and the high-speed uplink frame UL2 transmitted by the new vehicle-mounted device, the transmission rate of the high-speed uplink frame UL2 (256 kbit / s) is the transmission rate of the low-speed uplink frame UL1 (64 kbit / s). Compared to the transmission rate of the downlink optical DO (1024 kbit / s).
Therefore, it can be said that there is a higher possibility that the high-speed uplink frame UL2 cannot be received due to the influence of the reflected light of the downlink light DO, compared to the low-speed uplink frame UL1.

[Optical beacons to solve problems]
Therefore, in the present embodiment, the reflected light of the downlink light DO inhibits uplink communication in other lanes by narrowing the irradiation range in the road width direction of the downlink light DO transmitted by the beacon head 8 to an appropriate range. To suppress the above-mentioned problems.

FIG. 7 is a diagram illustrating a road width direction range of the downlink area DA of the optical beacon 4 according to the present embodiment.
The XY coordinates in FIG. 7 are orthogonal coordinates representing a planar position on a reference plane having a predetermined height H (= 1.0 m) from the road surface, and the origin is a position directly below the beacon head 8. The X coordinate represents the position in the vehicle traveling direction, and the upstream side is positive. The Y coordinate represents the position in the road width direction, and the left side is positive.

In FIG. 7, a broken line K extending from the beacon head 8 indicates a predetermined position Y1, −Y2 in the Y direction where the amount of light reaching the downlink is a predetermined reference value (= 4.5 μW / cm ² ), and the vicinity of the center of the beacon head 8. Represents a half line connecting
In the optical beacon 4 of the present embodiment, −Y2 ≦ Y ≦ Y1 at a predetermined position in the X direction (for example, at least one X direction position within a range including both ends from X = 0.70 to 6.04). The amount of light reaching the downlink is more than the reference value in the range, and the amount of light reaching the downlink is less than the reference value in the other ranges of −Y2> Y and Y> Y1.

That is, in the optical beacon 4 of the present embodiment, the amount of light reaching the downlink at a predetermined position in the vehicle traveling direction on the reference plane (an arbitrary X direction position included in the vehicle traveling direction range of the downlink area DA on the interface standard). Is set such that the distance Y in the road width direction where the value becomes the reference value (= 4.5 μW / cm ² ) is equal to or less than the predetermined distances Y1 and Y2, the irradiation range in the road width direction of the downlink light DO is limited. ing.

As long as the predetermined position in the vehicle traveling direction (X direction) is included in the range of the vehicle traveling direction in the downlink area DA, at least one arbitrary X direction position may be adopted. For example, X = 0. It is preferable to employ two locations of 70 m and 6.04 m.
In addition, when the predetermined position in the vehicle traveling direction (X direction) is limited to one place, one place of X = 0.70 m may be adopted.

According to the optical beacon 4 of the present embodiment, by defining the predetermined distances Y1 and Y2 in the Y direction to appropriate values, the irradiation range in the road width direction of the downlink light DO is not particularly limited (FIG. 6). In comparison, the amount of downlink light DO reaching the adjacent lane R2 from the beacon head 8 in the lane R1 decreases.
For this reason, it becomes difficult for reflected light of the downlink light DO of the lane R1 to reach the beacon head 8 of the adjacent lane R2, and the uplink light UO (particularly, the high-speed uplink frame UL2) transmitted by the vehicle 20 passing through the lane R2. , The possibility that the beacon head 8 in the lane R2 cannot be received can be reduced.

  In addition, if the irradiation range in the road width direction of the beacon head 8 installed in the lane R1 is limited, the probability that reflected light returns to the beacon head 8 in the lane R1 that is the own lane decreases, so the lane that is the own lane An indirect effect that the uplink communication in R1 can be inhibited from being inhibited by the reflected light of the downlink light DO from the lane R1 can be expected.

  The predetermined distances Y1 and Y2 for limiting the irradiation range of the downlink light DO may be selected from values in a range of W ≦ Y ≦ 1.5 × W, for example, where W is half of the lane width. For example, when W = 1.75 m, it is preferable to set the predetermined distances Y1 and Y2 to 2.0 m. In addition, the same value may be employ | adopted for the predetermined distance Y1 and the predetermined distance Y2, and a different value may be employ | adopted for it.

The irradiation range of the downlink light DO may be defined by an angle θ (see FIG. 7) in the road width direction with respect to the center line passing through the beacon head 8 instead of the Y coordinate.
That is, at a predetermined position in the vehicle traveling direction on the reference plane (range in the vehicle traveling direction of the downlink area DA according to the interface standard), the beacon head in which the amount of light reaching the downlink becomes the reference value (= 4.5 μW / cm ² ). By setting the angle θ in the road width direction with respect to the center line passing through 8 to be equal to or less than the predetermined angles θ1, θ2, the irradiation range in the road width direction of the downlink light DO may be limited.

For example, if Y1 = 2.0 m and the height from the reference plane to the beacon head 8 is Hb (= 4.5 m), the predetermined angle θ1 corresponding to the predetermined distance Y1 can be calculated by the following equation.
θ1 = tan ⁻¹ (Y1 / Hb)
= Tan ^-1 (2.0 / 4.5)

In the example of FIG. 7, as a measure for limiting the irradiation range of the downlink light DO in the road width direction, the Y coordinate (or angle coordinate θ) at which the amount of light reaching the downlink is a reference value (= 4.5 μW / cm ² ) or more. Limits the range.
However, as shown in FIG. 8, by limiting the amount of downlink arrival light at the reference position Q deviating from the focused lane R1 to a predetermined value or less, the irradiation range in the road width direction of the downlink light DO is limited. May be.

In the example of FIG. 8, it is assumed that the irradiation range of the beacon head 8 installed in the lane R1 is limited. The reference position Q in FIG. 8 is located outside the lane R1, and the specific coordinate values are X = 6.04m and Y = 3.5m.
In this case, by setting the amount of downlink arrival light at the reference position Q on the reference plane to a predetermined value (for example, 1.0 μW / cm ² ) or less, the downlink light DO of the beacon head 8 in the lane R1 in the road width direction is set. The irradiation range can be limited.

  A measure for limiting the irradiation range of the downlink light DO in the road width direction can be achieved by, for example, providing the communication light-emitting unit 13 with a light emission range limiting structure in the road width direction. Hereinafter, some specific examples of the light emission range limiting structure will be described.

[Specific example 1 of light emission range restriction structure]
FIGS. 9A to 9C are diagrams illustrating a specific example 1 of the light emission range limiting structure.
Specifically, FIG. 9A is a schematic view of the inside of the beacon head 8, FIG. 9B is a plan view of the light emitting unit 13 viewed from below, and FIG. 9C is a narrow directional element. FIG. Note that the X direction in FIG. 9 indicates the vehicle traveling direction, and the Y direction indicates the road width direction.

As shown in FIG. 9, the transmission / reception unit 11 in the housing 31 of the beacon head 8 includes a light emitting unit 13 and a light receiving unit 14 for communication. The light emitting unit 13 has a structure in which a plurality of narrow directivity elements 33 are arranged vertically and horizontally with respect to the circuit board 32.
The narrow directivity element 33 is made of, for example, an improved product of a surface mount type light emitting element (SMD: Surface Mount Device) 34, and includes the SMD 34 and a lens 35 made of, for example, a transparent resin bonded to the light emitting surface of the SMD 34. Prepare.

The SMD 34 is a light-emitting element having a relatively large full width at half maximum (for example, about 60 degrees). However, by attaching a lens 35 having a predetermined shape to the light emitting surface, the full width at half maximum in the Y direction is narrower than the full width at half maximum in the X direction. Yes.
Specifically, the lens 35 has a curved shape that is flat in the Y direction, in which the cross section in the X direction is substantially semicircular and the cross section in the Y direction is a vertically long semi-elliptical shape. Thereby, the directivity in the Y direction of the narrow directivity element 33 is narrower than the directivity in the X direction.

By mounting the narrow directional element 33 employing such a directional lens 35 on the circuit board 32, the light emitting unit 13 in which the light emission range in the road width direction (Y direction) is limited can be manufactured.
For this reason, by mounting the light emitting unit 13 on the beacon head 8, the irradiation range in the road width direction of the downlink light DO can be limited.

[Specific example 2 of light emission range restriction structure]
FIG. 10 is a diagram illustrating a specific example 2 of the structure for limiting the light emission range.
Specifically, FIG. 10 is an exploded perspective view of the communication light emitting unit 13 housed in the beacon head 8. In addition, the X direction of FIG. 10 shows a vehicle advancing direction, and a Y direction shows a road width direction.

As shown in FIG. 10, the light emitting unit 13 of the specific example 2 includes a plate-like light emitting member 36 in which a plurality of SMDs 34 are mounted on a circuit board 32, and a light emitting unit 36 that is polymerized on the light emitting surface side. A translucent lens plate 37.
The lens plate 37 is integrally formed with a plurality of lens portions 38 disposed at corresponding positions of the SMD 34. Each lens portion 38 has a substantially curved shape that is flat in the Y direction, in which the cross section in the X direction is substantially semicircular and the cross section in the Y direction is a vertically long semi-elliptical shape.

Thereby, the directivity in the Y direction of the narrow directivity element 33 of each lens unit 38 is narrower than the directivity in the X direction. By covering the light emitting surface side of the light emitting member 36 with the lens plate 37 on which the directional lens portion 38 is formed, the light emitting unit 13 in which the light emission range in the road width direction (Y direction) is limited can be manufactured. .
For this reason, by mounting the light emitting unit 13 on the beacon head 8, the irradiation range in the road width direction of the downlink light DO can be limited.

  In FIG. 10, the light emitting member 36 in which the SMD 34 is mounted alone is adopted. However, the light emitting element constituting the light emitting member 36 has a lens provided on the light emitting surface of the SMD 34 or a bullet structure other than the SMD 34. The LED may be adopted.

[Specific Example 3 of Light Emission Range Limiting Structure]
11A to 11C are diagrams showing a specific example 3 of the light emission range limiting structure.
Specifically, FIG. 11 (a) is a schematic diagram of the inside of the beacon head 8, FIG. 11 (b) is a plan view of the light emitting unit 13 viewed from below, and FIG. 11 (c) is another light emission. It is the top view which looked at the unit 13 from the bottom. Note that the X direction in FIG. 11 indicates the vehicle traveling direction, and the Y direction indicates the road width direction.

As shown in FIG. 11, the transmission / reception unit 11 in the housing 31 of the beacon head 8 includes a light emitting unit 13 and a light receiving unit 14 for communication. The light emitting unit 13 includes a plurality of light emitting elements 39 arranged vertically and horizontally with respect to the circuit board 32, and a plurality of shielding plates 40 provided at positions sandwiching the light emitting elements 39 from both the left and right sides.
The light emitting element 39 is formed of, for example, a bullet structure LED, but may be a surface mount type light emitting element (SMD 34).

The shielding plates 40 are arranged at intervals in the road width direction (Y direction) so as to shield the light emitting elements 39 arranged in a row in the vehicle traveling direction (X direction) from both the left and right sides, and hang downward from the position. It extends in a shape.
Although the fixing method of the shielding plate 40 is arbitrary, the upper end edge of the shielding plate 40 is fixed to the circuit board 32 in the illustrated example.

In the example of FIG. 11A, the shielding plate 40 penetrates the window portion of the casing 31 in the vertical direction. However, the shielding plate 40 may be accommodated in the casing 31 or the casing 31. It may be exposed in a hanging manner from the bottom surface.
As shown in FIG. 11B, a pair of shielding plates 40 may be provided with respect to the column in the X direction. Alternatively, as shown in FIG. It may be a plurality of small pieces of members.

By shielding the light emitting element 39 mounted on the circuit board 32 with the shielding plate 40, the light emitting unit 13 in which the light emission range in the road width direction (Y direction) is limited can be manufactured.
For this reason, by mounting the light emitting unit 13 on the beacon head 8, the irradiation range in the road width direction of the downlink light DO can be limited.

[Specific example 4 of light emission range restriction structure]
FIG. 12 is a diagram illustrating a specific example 4 of the light emission range limiting structure.
Specifically, FIG. 12 is a schematic diagram of the inside of the beacon head 8. Note that the X direction in FIG. 12 indicates the vehicle traveling direction, and the Y direction indicates the road width direction.

As shown in FIG. 12, the light emitting unit 13 in the housing 31 of the beacon head 8 includes a light source member 42 having a plurality of light emitting elements and a reflecting member 43 that substantially parallelizes the downlink light DO emitted from the light source member 42. With.
The reflecting surface of the reflecting member 43 is a parabolic surface with respect to the Y direction, and the light source member 42 is a substantially point light source having a sufficiently small light emitting portion as compared with the reflecting surface of the reflecting member 43. It is arranged near the focal point.

By adopting the reflecting member 43 that collimates the downlink light DO in the beacon head 8, the irradiation range of the downlink light DO in the road width direction can be limited.
In addition, the downlink light DO collimated by the reflection member 43 is, for example, “reflector method” or “lens cut method” in which the light source member 42 is covered with a lens having a cut surface with a complicated pattern. The irradiation range may be narrowed down in a predetermined direction.

[Other Embodiments]
By the way, since the vehicle-mounted head 22 of the vehicle-mounted device 2 is often installed on the left side of the dashboard in the vehicle 20, the uplink light UO of the vehicle 20 passing through the lane R1 is only the beacon head 8 in the lane R1. And may reach the beacon head 8 in the lane R2.
In addition, when the vehicle 20 travels across the line between the lanes R1 and R2 when the lane is changed, the uplink light UO may reach the beacon head 8 in another adjacent lane R2.

When the same uplink light DO arrives at a plurality of beacon heads 8, if the uplink signal received by the beacon controller 7 is transmitted as it is to the central device 3, the amount of data is particularly large in the case of the high-speed uplink frame UL2. Therefore, the communication line 5 may be tightened.
Therefore, in order to prevent the uplink light DO from reaching the beacon head 8 in another lane, a mechanism for limiting the irradiation range in the road width direction is also referred to as an in-vehicle head 22 (also referred to as an “optical beacon antenna”) mounted on the vehicle 20. .) Is also preferably adopted.

Even if the uplink light DO reaches a plurality of beacon heads 8, the beacon controller 7 performs at least one of the following data selection processes (a) to (d) and the merge process (d). If executed, it is possible to prevent the same uplink signal (such as the high-speed frame UL2) from being transmitted to the central apparatus 3 repeatedly.
That is, when a plurality of high-speed uplink signals with the same vehicle ID are detected within a predetermined time (for example, 1 to several seconds), the beacon controller 7 executes the above processing and determines an uplink signal to be transmitted. Is preferred.

(A) An uplink signal having a small or large lane number is selected from among a plurality of uplink signals having the same vehicle ID.
(B) From among a plurality of uplink signals having the same vehicle ID, an uplink signal having a reception time earlier or later is selected.

(C) An uplink signal having a large number of frames is selected from a plurality of uplink signals having the same vehicle ID.
(D) For each uplink signal obtained in a plurality of lanes R1 and R2, “OR” is performed for each frame number, thereby performing an uplink signal merging process.

A specific example of the data selection process (a) is as follows, for example.
In the case of selecting only the uplink signal having the smaller lane number, for example, the uplink light having the same vehicle ID although the vehicle 20 is traveling on the lane of number 1 on a two-lane road. When DO reaches both the beacon head 8 of the lane number 1 and the beacon head 8 of the lane number 2, the beacon controller 7 confirms the lane number included in both uplink signals, and the lane number is Only the uplink signal with the number 1 is selected and transmitted to the central unit 3.

A specific example of the data selection process (b) is as follows, for example.
In the case of selecting only the previous uplink signal at the reception time, for example, the uplink light DO is a beacon of the number 1 lane even though the vehicle 20 is traveling on the number 1 lane on the two-lane road. If the head 8 arrives at the time “10: 23: 11.400” and another uplink light DO having the same vehicle ID reaches the beacon head 8 of the lane number 2 at the time “10: 23: 11.401”, the beacon The controller 7 confirms the reception time included in both uplink signals, and selects only the uplink signal with the earlier reception time (uplink signal reaching the head of the lane with the lane number 1). To the central device 3.

A specific example of the data selection process (c) is as follows, for example.
When selecting only an uplink signal with a large number of frames, for example, an uplink light DO having the same vehicle ID is number 1 even though the vehicle is traveling on a lane number 1 on a two-lane road. The lane beacon head 8 and the beacon head 8 of the number 2 lane reach both, and the uplink signal of the beacon head 8 of the number 1 lane is 16 out of 16 frames, and the beacon head 8 of the number 2 lane If the uplink signal is 12 out of 16 frames, the beacon controller 7 selects only the uplink signal with the larger number of frames (uplink signal reaching the head of the lane with the lane number 1). Then, the data is transmitted to the central device 3.

A specific example of the merge process (d) is as follows, for example.
In the case of merging by taking OR for each frame number, for example, the uplink light DO having the same vehicle ID is numbered even though the vehicle 20 is traveling on the lane of number 1 on a two-lane road. Both the beacon head 8 of the lane 1 and the beacon head 8 of the lane number 2 reach the beacon head 8 of the lane number 1, and the uplink signals of the beacon head 8 of the lane number 1 are 1 to 3, 5 to 8, and 10 to 16 frames. Yes, if the uplink signal of the beacon head 8 in the lane number 2 is 1, 2, 4, 5, 8, 9, 12 out of 16 frames, the beacon controller 7 OR and take frames 4 and 9 in the uplink signal of the head of the lane number 2 and frames 1-3, 5-8 and 10-16 in the uplink signal of the head of the lane number 1 Integration was, transmits frames 1-16 to the central unit 3.

If the central device 3 receives the same uplink signal by passing through the beacon controller 7, the central device 3 executes at least one of the above processes (a) to (d). It is preferable.
In this way, it is possible to prevent a plurality of the same uplink signals transmitted by one vehicle 20 from being misunderstood as data relating to the two vehicles 20 and performing erroneous traffic signal control.

  The embodiments disclosed herein are illustrative in all respects and should be considered not restrictive. The scope of the right of the present invention is shown not by the contents of the above-described embodiment but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Traffic control system 2 Vehicle equipment 3 Central apparatus 4 Optical beacon 5 Communication line 6 Communication part 7 Beacon controller 8 Beacon head 11 Transmission / reception unit 12 Sensor unit 13 Light emitting unit for communication 14 Light receiving unit for communication 15 Light emitting unit for detection DESCRIPTION OF SYMBOLS 16 Light-receiving unit for a detection 17 Support | pillar 18 Beam member 20 Vehicle 21 Car-mounted controller 22 Car-mounted head 23 Light transmitter 24 Light receiver 25 Navigation device 31 Housing 32 Circuit board 33 Narrow directional element 34 SMD
35 Lens 36 Light emitting member 37 Lens plate 38 Lens part 39 Light emitting element 40 Shielding plate 42 Light source member 43 Reflecting member

Claims (3)

An optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal,
A beacon head installed on a lane included in the road;
A beacon controller that causes the beacon head to transmit downlink light, and
An optical beacon in which a downlink arrival light amount at a reference position located outside the lane on a reference plane having a predetermined height from a road surface is set to a predetermined value or less. An optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal,
A beacon head installed on a lane included in the road;
A beacon controller that causes the beacon head to transmit downlink light, and
The distance in the road width direction from the center line passing through the beacon head where the amount of light reaching the downlink is a reference value at a predetermined position in the vehicle traveling direction on the reference plane at a predetermined height from the road surface is set to be a predetermined distance or less. Light beacon. An optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal,
A beacon head installed on a lane included in the road;
A beacon controller that causes the beacon head to transmit downlink light, and
At a predetermined position in the vehicle traveling direction on a reference plane at a predetermined height from the road surface, the angle in the road width direction with respect to the center line passing through the beacon head where the amount of light reaching the downlink is a reference value is set to be a predetermined angle or less. Light beacon.

Images