JP4687817B2 - Road-to-vehicle communication system and optical beacon - Google Patents

Description

The present invention relates to a road-to-vehicle communication system that performs bidirectional communication using an optical signal between an optical beacon installed on a road side and an in-vehicle device mounted on a vehicle, and light that can be used in the road-to-vehicle communication system. it relates to the beacons.

As a traffic information service using a road-to-vehicle communication system, so-called VICS (Vehicle Information and Communication System) using optical beacons, radio wave beacons or FM multiplex broadcasting has already been developed. Among these, the optical beacon employs optical communication using near infrared rays as a communication medium, and enables two-way 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 optical beacon on the infrastructure side, and conversely, traffic jam information, section travel time information, event regulation information, and lanes Downlink information including notification information and the like is transmitted from the optical beacon to the vehicle-mounted device (see, for example, Patent Document 1).

The optical beacon includes a beacon head (projector / receiver) that performs bidirectional communication with an in-vehicle device. The projector / receiver includes a light-emitting diode (LED) that transmits downlink information and an in-vehicle device. And a photo sensor for receiving the uplink information.
For example, as shown in FIG. 11, the communication area A of the beacon head (projector / receiver) 108 of the optical beacon 104 is set on the upstream side from immediately below. According to the “near-infrared interface standard” of the optical beacon (optical vehicle sensor) 104, the uplink area UA overlaps with the upstream part of the downlink area DA in the vehicle traveling direction (the right part in FIG. 11). The upstream ends of the downlink area DA and the uplink area UA are made to coincide with each other. In practice, the currently set upstream end of the downlink area DA is often set upstream (for example, c ′ in FIG. 11) from the upstream end c of the uplink area UA.

  Therefore, the vehicle traveling direction length of the downlink area DA matches the same direction length of the entire communication area A. Further, according to the above standard, in the case of the optical beacon 104 for general roads, the downstream end a of the downlink area DA is located on the upstream side of 1.0 to 1.3 m immediately below the beacon head 108, and the downlink The distance from the downstream end a of the area DA to the downstream end b of the uplink area UA is defined as 2.1 m, and the distance from the downstream end b of the uplink area UA to the upstream end c of the area UA is 1.6 m. It is prescribed. Accordingly, in this case, the total length of the communication area A in the vehicle traveling direction is 3.7 m.

JP 2005-268925 A

In the road-to-vehicle communication system, the following communication is performed between the optical beacon 104 and the vehicle-mounted device 102. First, the optical beacon 104 first always transmits the first downlink information including the lane notification information (no vehicle ID) to the downlink area DA of the road at a predetermined transmission cycle.
When the vehicle enters the downlink area DA and the projector / receiver (vehicle-mounted head) of the vehicle-mounted device 102 mounted on the vehicle receives the first downlink information, the vehicle-mounted device 102 receives the own vehicle. Transmission of uplink information including lane notification information storing the ID is started.
Then, when the beacon head 108 of the optical beacon 104 receives the uplink information, the optical beacon 104 performs downlink switching, and the second down including the lane notification information having the vehicle ID with respect to the in-vehicle device 102. Start sending link information. This second downlink information is repeatedly transmitted as much as possible within a predetermined time and is received by the in-vehicle device 102.

  By such a road-to-vehicle communication system using an optical beacon, for example, a specific position in the communication area A (for example, the upstream end in the vehicle traveling direction) is regarded as the position of the vehicle (onboard unit 102), and the downstream from the specific position. The “distance information” to the predetermined position P0 on the side (for example, the stop line 40 provided in front of the traffic light) is included in the second downlink information, and the in-vehicle device 102 that has received this distance information Using the distance information, the vehicle may be braked so as to be forcibly stopped before the stop line 40, or the driver may be advised to stop or decelerate to provide safe driving assistance to the driver. (For example, Japanese Patent Application Nos. 2006-121692 and 2006-121700 proposed by the present applicant).

However, when such safe driving support is performed, there are the following problems.
Currently, the communication area A of the optical beacon 104 that is actually operated, particularly the uplink area UA, receives the uplink information from the in-vehicle device 102 more reliably. For example, as shown by a virtual line in FIG. In many cases, the area is considerably wider than the official area defined by the standard (for example, an area indicated by Δdb′c ′). Similarly, the downlink area DA is often set more than the standard area.
Thus, if the communication area A is wider than the official area, the difference between the specific position in the communication area A that is the starting point of the “distance information” and the actual position when the vehicle receives the distance information Is likely to increase, and the accuracy of the distance information decreases. For this reason, the accuracy of the safe driving support using the distance information is similarly reduced. For example, although the vehicle is braked so as to stop before the stop line 40 by the safe driving support function, A situation may occur in which the vehicle stops after the stop line 40 is exceeded.

Therefore, the uplink region is configured by dividing the uplink region into a plurality of divided regions in the vehicle traveling direction, and providing the projector / receiver with a plurality of receiving units that receive uplink information corresponding to each divided region. It can be considered that each divided region is set narrow in the vehicle traveling direction.
In this case, the predetermined downlink information after receiving the uplink information includes distance information related to the distance from the position in the divided region corresponding to the receiving unit that has received the uplink information to the predetermined position downstream thereof. If it does in this way, it will become possible to make it recognize the exact distance to a predetermined position in vehicle equipment.

However, in the case where a plurality of receiving units are provided corresponding to the divided areas obtained by dividing the uplink area in the vehicle traveling direction as described above (hereinafter sometimes referred to as “PD division type”), the vehicle is divided into the divided areas. When uplink information is transmitted from the in-vehicle device while traveling in the vicinity of the boundary line (boundary part), the two reception units corresponding to the two divided regions straddling the boundary line simultaneously transmit the uplink information. There is a possibility of receiving.
In this case, since it is not possible to specify one receiving unit that has received the uplink information, it is not possible to specify the upstream position of the distance information to be estimated as the transmission position of the uplink information, resulting in inconvenience that the distance information cannot be generated.

In the present invention, in view of such a situation, in a PD division type optical beacon and a road-to-vehicle communication system using the same, two reception units corresponding to two division regions adjacent to or overlapping each other simultaneously transmit uplink information. It is an object to be able to determine the transmission position of uplink information even if it is received .

  The road-to-vehicle communication system of the present invention includes a light having a light emitter / receiver in which a communication region including an uplink region capable of receiving uplink information and a downlink region capable of transmitting downlink information is set to a predetermined range of a road. A road-to-vehicle communication system comprising a beacon and an in-vehicle device that transmits and receives the uplink information and the downlink information to and from the projector / receiver in the communication area. The uplink area is divided into a plurality of divided areas in the vehicle traveling direction, and the projector / receiver has a plurality of receiving units for receiving the uplink information corresponding to the divided areas. It is characterized by.

Further, the light beacon of the present invention comprises a projector-receiver communication area consisting of a transmittable downlink section the possible uplink region and the down link information receive uplinks information is set to a predetermined range of the road An optical beacon, wherein the uplink region is divided into a plurality of divided regions in a vehicle traveling direction, and the light receiver / receiver includes a plurality of receiving units that receive the uplink information corresponding to the divided regions. It is characterized by having.

Further, in these cases, the road-to-vehicle communication system and the optical beacon have a communication control unit that transmits predetermined downlink information to the projector / receiver after receiving the uplink information by the receiving unit, When the uplink information is simultaneously received by two receiving units corresponding to two adjacent divided areas, the predetermined downlink information relates to a distance from a boundary portion to the predetermined position in the two divided areas. Contains distance information.

Alternatively, in the road-to-vehicle communication system and the optical beacon, the uplink region includes a divided region having a region overlapping with another divided region adjacent in the vehicle traveling direction, and corresponds to two divided regions overlapping each other. When the uplink information is received simultaneously by two receiving units, the predetermined downlink information includes distance information related to a distance from a position in the overlapping area in the two divided areas to the predetermined position.

According to the road-to-vehicle communication system and the optical beacon, even when two receivers receive uplink information at the same time, distance information with the position in the boundary or overlapping area as the upstream end is included in the predetermined downlink information Therefore, the transmission position of the uplink information can be determined by the upstream end, and the distance information provided to the vehicle side can be generated.

In the above case, the optical beacon has an estimation unit that estimates the position of the vehicle in the boundary portion or the overlapping region based on the light reception levels of the two light reception units that have received uplink information at the same time. It is preferable that downlink information includes the distance information in which an upstream end is set based on the position of the vehicle estimated by the estimation unit.
In this case, since the estimation unit accurately estimates the position of the vehicle based on the light reception levels of the two light receiving units and sets the upstream end of the distance information based on the estimated vehicle position, more accurate distance information Can be provided to the vehicle-mounted device side .

According to the present invention, in a PD split type optical beacon and a road-to-vehicle communication system using the same, even if two receiving units corresponding to two divided areas adjacent to each other receive uplink information at the same time, The transmission position of the uplink information can be determined .

1 is a block diagram showing an overall configuration of a road-vehicle communication system according to a first embodiment of the present invention. It is a top view of an optical beacon. It is a side view which shows the communication area | region of an optical beacon. It is a schematic block diagram of the vehicle equipment in which this vehicle equipment is mounted, and the vehicle equipment which carries out road-to-vehicle communication with an optical beacon. It is a conceptual diagram which shows the procedure and data content of the road-vehicle communication performed in a communication area. It is the schematic which shows the procedure which transmits downlink information, after receiving uplink information by one receiving part. It is a side view which expands and shows a part of uplink area | region about 2nd Embodiment of this invention. It is a side view which shows the communication area | region of the optical beacon which concerns on 3rd Embodiment of this invention. It is a side view which expands and shows a part of the uplink area | region. It is a side view which shows the communication area | region of the optical beacon which concerns on 4th Embodiment of this invention. It is a side view which shows the communication area | region of the conventional optical beacon.

Of the first to fourth embodiments described below, only when the two receiving units simultaneously receive uplink information (second and third embodiments) is an embodiment related to the present invention.
[First Embodiment]
[Overall system configuration]
FIG. 1 is a block diagram showing the overall configuration of the road-vehicle communication system according to the first embodiment.
As shown in FIG. 1, the road-to-vehicle communication system includes an infrastructure-side traffic control system 1 and an in-vehicle device 2 mounted on each vehicle C traveling on a road R.
The traffic control system 1 includes a central device 3 provided in a control room, and a large number of optical beacons (optical vehicle detectors) 4 installed at various locations on the road R. The optical beacon 4 performs bidirectional communication with the in-vehicle device 2 by optical communication using near infrared rays as a communication medium. The central device 3 is provided in the traffic control room.

[Configuration of optical beacon]
The optical beacon 4 includes a communication unit 6 that is a communication interface connected to the central apparatus 3 via a communication line 5 such as a telephone line, a beacon controller 7 to which the communication unit 6 is connected, and the beacon controller 7. And a plurality (four in the illustrated example) of beacon heads (projector / receiver) 8 connected to the sensor interface.
Each beacon head 8 is configured by housing a light emitting diode (LED) 10 and a photosensor (reception unit) 11 inside a casing (see FIG. 3). Among them, the LED 10 emits downlink information made of near infrared rays to a communication area A described later, and the photo sensor 11 receives uplink information made of near infrared rays from the in-vehicle device 2. The beacon head 8 of the present embodiment is provided with a plurality (four) of photosensors 11.

FIG. 2 is a plan view of the optical beacon 4. As shown in FIG. 2, the optical beacon 4 of this embodiment is installed on a road R having a plurality of lanes R1 to R4 (four in the illustrated example) in the same direction, and corresponds to each lane R1 to R4. The plurality of beacon heads 8 provided and a single beacon controller 7 serving as a control unit that collectively controls the beacon heads 8.
The beacon controller 7 includes a programmable microcomputer having a CPU, a memory (RAM), and a storage device (ROM). The beacon controller 7 is a two-way communication with the central device 3 by the communication unit 6 (FIG. 1), and is mounted on the vehicle by the beacon head 8. It has a function as a communication control unit that performs road-to-vehicle communication with the machine 2. The contents of road-to-vehicle communication by the beacon controller 7 will be described later.

The beacon controller 7 is installed on a support column 13 standing on the side of the road, and each beacon head 8 is attached to an installation bar 14 installed horizontally on the road R side from the support column 13, and each lane R1 of the road R. It is arrange | positioned just above -R4.
The LED 10 of each beacon head 8 emits near-infrared rays toward the upstream side in the vehicle traveling direction rather than directly below the lanes R1 to R4, thereby performing road-to-vehicle communication with the in-vehicle device 2. Is set on the upstream side of the head 8.

[About communication area]
FIG. 3 is a side view showing the communication area A of the optical beacon 4.
As shown in FIG. 3, the communication area A of the optical beacon 4 is a downlink area in which the in-vehicle head 27 which is the light emitter / receiver of the in-vehicle device 2 can receive downlink information (in FIG. 3, a solid line hatching is provided). DA) and an uplink area (area provided with broken-line hatching in FIG. 3) UA in which the beacon head 8 of the optical beacon 4 can receive uplink information from the in-vehicle head 27.

  The downlink area DA is set in a range indicated by Δdac having apexes at the light emitting / receiving position d of the beacon head 8 and the positions a and c on the road R. The uplink area UA is set in the range indicated by Δdbc with the position d and the positions b and c on the road R as vertices. Therefore, the upstream end c of the downlink area DA and the uplink area UA coincide with each other, and the uplink area UA overlaps with the upstream portion (right side portion in FIG. 3) of the downlink area DA in the vehicle traveling direction. Further, the vehicle traveling direction length of the downlink area DA coincides with the same direction length of the entire communication area A.

  According to the “near infrared interface standard” of the optical beacon (optical vehicle sensor) 4, the formal area dimensions of the downlink area DA and the uplink area UA are defined. In this rule, in the case of an optical beacon 4 for a general road, the downstream end a of the downlink area DA is located 1.0 to 1.3 m upstream immediately below the beacon head 8 and is downstream of the downlink area DA. The distance from the end a to the downstream end b of the uplink area UA is defined as 2.1 m. Further, the distance from the downstream end b of the uplink area UA to the upstream end c of the area UA is defined as 1.6 m. Therefore, the total length (the length between ac) of the official communication area A in the vehicle traveling direction is 3.7 m.

However, in this embodiment, the distance from the downstream end b of the uplink area UA to the upstream end c of the area UA is set longer to the upstream side and the downstream side than the above definition. As a result, the uplink area UA extends in the vehicle traveling direction from the above definition, and the downlink area DA also extends in the vehicle traveling direction from the above definition.
Thus, when the uplink area UA and the downlink area DA are widened, the certainty of transmission / reception of uplink information and downlink information between the in-vehicle device 2 and the optical beacon 4 is increased.

Further, the uplink area UA is divided into a plurality in the vehicle traveling direction. Specifically, the uplink area UA is divided into four by three boundary lines (boundary portions) K having a position d as an upper end and positions e1 to e3 on the road R as lower ends.
The four photosensors 11 (FIG. 1) provided in the beacon head 8 use the divided areas UA1 to UA4 of the uplink area UA as reception areas. Therefore, for example, the uplink information transmitted from the in-vehicle head 27 in the divided area UA1 is received by the photosensor 11 corresponding to the divided area UA1.

[Configuration of in-vehicle device and vehicle]
FIG. 4 is a schematic configuration diagram of the in-vehicle device 2 that performs road-to-vehicle communication with the optical beacon 4 and a vehicle C in which the in-vehicle device 2 is mounted.
As shown in FIG. 4, the vehicle C includes a vehicle body 21 having a driver's boarding seat (not shown), the vehicle-mounted device 2 mounted on the vehicle body 21, and electronic control that integrally controls each part of the vehicle C. An apparatus (ECU) 22, an engine 23 that drives the vehicle body 21, a brake device 24 that brakes the vehicle body 21, and a speed detector 25 that constantly detects the current speed of the vehicle C are provided. The ECU 22 performs various controls on the vehicle C, such as drive control of the engine 23 based on the accelerator operation of the driver and braking control based on the brake operation.

The in-vehicle device 2 includes an in-vehicle computer 26, an in-vehicle head (projector / receiver) 27 connected to the sensor interface of the computer 26, a display 28 and a speaker device 29 as a human interface for the driver of the passenger seat. Yes.
The vehicle-mounted head 27 includes a light emitting diode (LED) and a photosensor (not shown), similar to the light beacon projector / receiver 8. Among these, the LED emits uplink information composed of near infrared rays, and the photosensor receives downlink information composed of near infrared rays emitted to the communication area A.

The in-vehicle computer 26 includes a programmable microcomputer having a CPU, a memory (RAM), and a storage device (ROM), and performs control processing for road-to-vehicle communication with the optical beacon 4 by the in-vehicle head 27.
The in-vehicle computer 26 stores a program for executing predetermined functions in a storage device, and includes a distance recognition unit 30, a correction unit 31, and a support control unit 32 as functional units to be executed by the program. . The processing contents of these functional units 30, 31, and 32 will be described later.

[Contents of road-to-vehicle communication]
FIG. 5 shows a two-way road-to-vehicle communication procedure performed between the beacon head 8 and the vehicle-mounted head 27 in the communication area A. Hereinafter, the contents of the road-to-vehicle communication of the present embodiment will be described with reference to FIG.
First, the beacon controller 7 of the optical beacon 4 sends the first downlink information 34 including the lane notification information from the beacon heads 8 corresponding to the lanes R1 to R4 as the first information before switching the downlink. The transmission continues to the downlink area DA of each lane R1 to R4 at a predetermined transmission cycle (F1 in FIG. 5). At this stage, the vehicle ID is not yet stored in the lane notification information.

When the vehicle C equipped with the in-vehicle device 2 enters the actual downlink area DA, the in-vehicle head 27 of the in-vehicle device 2 receives the first downlink information 34 including the lane notification information (no vehicle ID).
At this time, the in-vehicle computer 26 of the in-vehicle device 2 recognizes that the vehicle C exists in the actual communication area A. Thereafter, the in-vehicle computer 26 starts transmission of the uplink information 35 (F2 in FIG. 5), and transmits this uplink information 35 to the beacon head 8 at a predetermined transmission cycle (uplink transmission cycle) (FIG. 5). 5 F3).

  The in-vehicle computer 26 stores a specific vehicle ID for the vehicle C in the uplink information 35 and transmits the uplink information 35. If the in-vehicle computer 26 has travel time information between beacons, this information is also uploaded. It is included in the link information 35. The in-vehicle computer 26 continues to transmit the uplink information 35 until it recognizes that the beacon controller 7 of the optical beacon 4 has switched the downlink.

  On the other hand, when the beacon head 8 of the optical beacon 4 receives the uplink information 35 (F4 in FIG. 5), the beacon controller 7 performs downlink switching, and uses the lane notification information having the vehicle ID information as the second information. The transmission of the included second downlink information 36 is started (F5 in FIG. 5), and the transmission of the second downlink information 36 is repeated as much as possible within a predetermined time (F6 in FIG. 5).

  The lane notification information includes a field for storing a vehicle ID for each lane R1 to R4 (FIG. 2), and a lane number can be assigned to each vehicle ID. For this reason, the in-vehicle computer 26 of each vehicle C traveling in different lanes R1 to R4 determines which lane R1 to R4 the host vehicle is in by determining which of the storage fields includes the vehicle ID of the host vehicle. Can recognize if you are driving.

The second downlink information 36 includes traffic information, section travel time information, event regulation information, and support information for safe driving support for the driver, in addition to the lane notification information including the vehicle ID. Yes.
This support information includes signal information that is timing information for changing the color of the traffic light downstream from the optical beacon 4 and length information from the communication area A to a predetermined position (for example, a stop line) downstream thereof. Some distance information is included.

As shown in FIG. 5, the second downlink information 36 includes a single or a plurality of minimum frames 37. According to the “near infrared interface standard”, the data amount of the minimum frame 37 is defined as a total of 128 bytes, and 5 bytes are allocated to the header portion 38 and 123 bytes are allocated to the actual data portion 39.
According to the standard, the second downlink information 36 can be composed of 1 to 80 minimum frames 37, and the transmittable time is set to 250 ms. The downlink information 36 includes an arbitrary number of minimum frames 37 corresponding to the amount of information to be transmitted, and is repeatedly transmitted within the range of the transmittable time.

The transmission period of the minimum frame 37 is about 1 ms. Therefore, for example, when one downlink information 36 is constituted by three minimum frames 37, the transmission period of the downlink information 36 is about 3 ms. Therefore, the downlink information 36 has a predetermined transmittable time (250 ms). ) Will be repeatedly transmitted about 80 times during this period.
The in-vehicle computer 26 of the in-vehicle device 2 recognizes the downlink switching in the optical beacon 4 at the time of receiving the second downlink information 36 (F7 in FIG. 6), and transmits the uplink information 35 at this time. Stop.

As shown in FIG. 3, the road-to-vehicle communication system according to the present embodiment recognizes the distance from the communication area A to the predetermined position P0 on the downstream side, and performs position location (F8 in FIG. 5). It functions as a distance recognition system that provides safe driving support to the driver.
Hereinafter, the content of the distance information described above and distance recognition for safe driving support performed by the vehicle-mounted device 2 based on the content will be described.

[Contents of distance information]
As shown in FIG. 3, the beacon controller 7 of the optical beacon 4 stores in advance the distance information that is a numerical value of distances L1 to L4 from the predetermined positions P1 to P4 in the communication area A to the predetermined position P0 on the downstream side thereof. It is stored in the device. Then, the distance information about the distances L1 to L4 is stored in the transmission frame of the second downlink information 36, and the frame is repeatedly transmitted from the beacon head 8.
The downstream end (end point) P0 of the distances L1 to L4 is set, for example, at the position of the stop line 40 installed on the downstream side of the optical beacon 4 before the traffic light. Further, upstream ends (start points) P1 to P4 of the distances L1 to L4 are set at four locations according to the respective divided areas UA1 to UA4 of the uplink area UA. Specifically, the positions of the upstream ends P1 to P4 are set at approximately the center position in the vehicle traveling direction on the road R in each of the divided areas UA1 to UA4.

The beacon controller 7 selects any one of the distance information about the plurality of distances L1 to L4 stored in advance and stores it in the transmission frame of the second downlink information 36. Then, which distances L1 to L4 are selected is determined based on the photosensor 11 that has received the uplink information before switching the downlink.
For example, in the uppermost divided area UA1, the in-vehicle head 27 of the vehicle C traveling on the road R transmits the uplink information 35, and as shown in FIG. 6, the photosensor corresponding to the divided area UA1. When the (first receiving unit) 11 receives the uplink information 35, the beacon controller (downlink switching control unit) 7 identifies the photosensor 11 that has received the uplink information 35, and distance information corresponding thereto. While selecting L1, the downlink is switched and the second downlink information 36 including the distance information about the distance L1 is transmitted via the LED 10.

  When any of the photosensors (second to fourth receiving units) 11 corresponding to the other divided areas UA2 to UA4 receives the uplink information 35, the beacon controller 7 has the upstream points P2 to P4. One of the distances L2 to L4 is selected, and the second downlink information 36 including the distance information about the distances L2 to L4 is transmitted.

[Contents of distance recognition (safe driving support)]
As shown in FIG. 4, when the in-vehicle head 27 receives the second downlink information 36 including the distance information, the distance recognition unit 30 of the in-vehicle computer 26 includes the distance included in the frame of the downlink information 36. Information is extracted to recognize the distances L1 to L4.
And the assistance control part 32 of the vehicle-mounted computer 26 performs the safe driving assistance with respect to a driver using the distances L1-L4.

  For example, the support control unit 32 calculates a deceleration (negative acceleration) for stopping before the stop line 40 from the distances L1 to L4 to the stop line 40 and the current traveling speed of the vehicle C, The deceleration is notified to the ECU 22. The ECU 22 operates the brake device 24 so as to achieve the deceleration, whereby the vehicle C can be automatically stopped before the stop line 40.

Further, the safe driving support of the support control unit 32 may be alerting the driver using the display 28 or the speaker device 29.
For example, the distance L1 to the stop line 40 may be displayed on the display 28 by the support control unit 32. When the current traveling speed of the vehicle C is too fast, the support control unit 32 displays a warning for stopping or decelerating on the display 28, or outputs the warning from the speaker device 29 as a voice. May be.

Moreover, the assistance control part 32 can also perform safe driving assistance using the signal information contained in 2nd downlink information with the said distance information.
Here, the signal information refers to information related to the current or future signal lamp color displayed by the traffic signal device, and includes information (display schedule information) regarding the display continuation period of each signal lamp color, the display order, and the like. For example, “the current lamp color is blue and the scheduled duration is 5 seconds, the next lamp color is yellow and the scheduled duration is 8 seconds, and the next lamp color is a right turn blue arrow lamp and the scheduled duration is 10 seconds. It is information such as “second”.

  The support control unit 32 of the in-vehicle computer 27 that has received this signal information determines the distance from the distances L1 to L4 (the above-mentioned distance information) to the stop line 40 and the traveling speed or acceleration of the vehicle C until the stop line 40 is reached. After estimating the required time, the signal lamp color after the required time can be estimated. For example, if the current signal lamp color is a blue signal, but the signal lamp color is predicted to be a red signal when arriving at the stop line 40, it can be safely stopped before the stop line 40. Thus, control for braking the vehicle C is performed. Conversely, if it can be determined that the vehicle can safely pass through the intersection unless the vehicle is decelerated, the control for maintaining the speed of the vehicle C can be performed.

  In order to brake the vehicle C or maintain the speed, the support control unit 32 may directly control the brake device 24 (FIG. 4) and the accelerator of the vehicle. Further, the support control unit 32 may simply generate information related to braking and speed maintenance and notify the ECU 22 of the information to control the brake device 24 and the accelerator by the ECU 22. That is, the support control unit 32 may perform indirect control.

  In addition, the support control unit 32 may perform not only control led by the in-vehicle device but also operation for assisting the driving operation of the driver such as brake assist.

The support control unit 32 may notify the passenger of the vehicle C of the result of the signal lamp color estimation by voice or image information. For example, sound such as “Since the signal changes soon and should be stopped” is emitted from the speaker device 29 to the driver, or displayed on the display 28 such as a head-up display or a navigation device with characters or symbols. Can do.
For safe driving assistance, a human interface that does not notify the driver of information at an inappropriate timing or content, for example, it is possible to prevent notification by voice or image display during low-speed driving .

The signal information may be only the currently displayed lamp color and its duration, or information for one cycle may be provided collectively. Further, in addition to these pieces of information, parameter information related to the control, information on a time zone in which the control is performed, and the like may be included at the point where the point sensitive control is performed.
The signal information may be acquired from an optical beacon or may be acquired from an infrastructure device other than the optical beacon. In the latter case, for example, when the signal controller of the traffic signal is equipped with a wireless communication device, it may be acquired from the wireless communication device, or may be acquired by inter-vehicle communication from the preceding vehicle that acquired the signal information. Also good. The signal information receiving unit that receives the signal information may use the in-vehicle head 27 or may be another receiver provided in the in-vehicle device 2.

As described above in detail, according to the road-to-vehicle communication system of the present embodiment, the uplink area UA is divided into a plurality of divided areas UA1 to UA4, and the beacon head 8 corresponds to each of the divided areas UA1 to UA4. A plurality of photosensors 11 are provided, and distances L1 to L4 to a predetermined position P0 are selected according to the photosensor 11 that has received the uplink information 35, and the distance information is included in the second downlink information 36. Therefore, even if the entire uplink area UA is set wider in the vehicle traveling direction than prescribed, the starting point of the distance information (upstream end in the vehicle traveling direction) and the position of the actual vehicle (vehicle equipment 2) And the vehicle-mounted device 2 can accurately recognize the distance to the predetermined position P0. Therefore, safe driving support for the driver can be performed with high accuracy.
In other words, according to the road-to-vehicle communication system of the present embodiment, the uplink area UA can be expanded in the vehicle traveling direction, so that it is possible to more reliably receive the uplink information from the in-vehicle device 2. it can.

In addition, the road-to-vehicle communication system of the present embodiment is very useful because it is possible to accurately recognize the distance to the predetermined position P0 even under conditions where the reliability of road-to-vehicle communication is low. Hereinafter, this point will be described in detail.
In addition, the conditions with low reliability of road-to-vehicle communication include, for example, weather conditions such as rainy weather or heavy fog that light that transmits uplink information (uplink light) is difficult to reach the beacon head 8, or during rain The condition is such that the uplink light is blocked by operating the wiper of the vehicle C.

In general, if the reliability of road-to-vehicle communication is high, the uplink information 35 first transmitted in the uplink area UA is accurately received by the photosensor 11, and the in-vehicle computer 26 recognizes the switching of the downlink. The position of the vehicle C at the time of receiving (receiving the second downlink information) is considered to be approximately near the uppermost stream end c of the uplink area UA.
However, under conditions where the reliability of road-to-vehicle communication is low, the uplink information 35 initially transmitted in the uplink area UA may not be accurately received by the beacon head 8, and the in-vehicle computer 26 may switch the downlink. Until it can be recognized, the uplink information 35 is repeatedly transmitted every uplink transmission period. For this reason, the position of the vehicle C at the time of recognizing the downlink switching is farther downstream than the uppermost stream end c of the uplink area UA by the distance traveled while repeatedly transmitting the uplink information 35. It becomes a spot.

  At this time, if the starting point of the distance information included in the second downlink information is the uppermost stream end c of the uplink area UA, the uppermost stream end c and the actual position of the vehicle C are greatly separated from each other. Recognition accuracy decreases. In particular, when the traveling speed of the vehicle is high or the uplink transmission cycle is set to be long, the distance recognition accuracy may be further reduced.

  In the case of this embodiment, since the uplink area UA is divided into the divided areas UA1 to UA4, even if the first uplink information 35 is not received in the divided area UA1 on the most upstream side, for example, the uplink information Since the second downlink information can include distance information starting from the positions in the other divided areas UA2 to UA4, the distance recognition accuracy hardly decreases.

In the above embodiment, the vehicle traveling direction length of each of the divided areas UA1 to UA4 can be set according to a level required as distance recognition accuracy. Moreover, the vehicle traveling direction lengths of the divided areas UA1 to UA4 may be different from each other.
In the present embodiment, the method of selecting the distance according to the photosensor 11 that received the uplink information 35 from the distances L1 to L4 and including the distance information in the second downlink information 36 has been described. However, for example, all of the distances L1 to L4 are given identification numbers and the like, all the distances L1 to L4 and the corresponding identification numbers are included in the second downlink information, and at the same time, the uplink information 35 is One identification number corresponding to the received photosensor 11 may also be included in the second downlink information 36. In this case, the distance recognition unit 30 of the in-vehicle computer 26 can select and recognize an accurate distance based on the first identification number included in the second downlink information 36. Further, when the in-vehicle computer 26 stores the distances L1 to L4 and their identification numbers in advance, only the one identification number corresponding to the photosensor 11 that has received the uplink information 35 is used as the second downlink information. May be included.

[Second Embodiment]
In the first embodiment, as shown in FIG. 3, the uplink information 35 is transmitted from the in-vehicle device 2 when the vehicle C is traveling near the boundary lines (boundary portions) K of the divided areas UA1 to UA4. Then, the two photosensors 11 corresponding to the two divided areas UA1 to UA4 straddling the boundary line K may receive the uplink information 35 at the same time. In such a case, in the first embodiment described above, it becomes impossible to select one of the plurality of distances L1 to L4 constituting the distance information.
Therefore, in the second embodiment, assuming such a situation, each boundary position e1, e2, e3 on the road R of the divided areas UA1 to UA4 is an upstream end, and each distance having a predetermined position P0 is a downstream end. Is also stored in advance in the storage device of the beacon controller 7. When the same uplink information is simultaneously received by the two photosensors 11, the beacon controller 7 determines the boundary positions e1, e2, and two boundary areas UA1 to UA4 corresponding to the two photosensors 11. The distance information about the distance with e3 as the upstream end is selected and included in the second downlink information 36.

  Therefore, in this embodiment, the choice of distance information further increases, and the in-vehicle device 2 can recognize a more accurate distance to the predetermined position P0. Therefore, safe driving support for the driver can be performed with higher accuracy.

  In the present embodiment, the boundary line (boundary portion) K can be assumed to have a predetermined width. For example, as shown for the divided areas UA3 and UA4 in FIG. 7, the predetermined width is provided in the vicinity of the downstream end of the divided area UA3 and the upstream end of the divided area UA4, and 2 corresponding to each divided area UA3 and UA4. Boundary portions UA3e and UA4e can be assumed in which two photosensors 11 (third and fourth receiving units) can simultaneously receive uplink information. In this case, when two boundary portions UA3e and UA4e are combined to set one boundary region UA34e, and the third and fourth receivers simultaneously receive uplink information, the position on the road R in the boundary region UA34e ( For example, distance information having an upstream end at a substantially central position in the vehicle traveling direction) can be included in the second downlink information 36.

Further, when uplink information is simultaneously received by the third and fourth receivers as described above, by comparing the received light levels, the vehicle-mounted device 2 of the vehicle C is located in the boundary area of the UA 34e. The beacon controller 7 is provided with an estimation unit that estimates whether the uplink information 35 is transmitted, and the upstream end of the distance information can be set based on the point estimated by the estimation unit.
For example, in the boundary area UA34e, if the light reception level of the third reception unit is high and the light reception level of the fourth reception part is low, the estimation unit causes the vehicle (onboard unit 2) to move closer to the upstream side in the boundary area UA34e. It is estimated that the uplink information is transmitted at a position (close to the divided area U3). Furthermore, the estimation unit can estimate the transmission position of the uplink information of the vehicle after allocating the area length of the boundary area UA34e according to the ratio of the received light level.

Specifically, when the light receiving level of the third receiving unit is 3.0 μW / cm 2 and the light receiving level of the fourth receiving unit is 1.0 μW / cm 2, the boundary is based on the ratio (3: 1) of both light receiving levels. The area length of the area UA34e is equally divided into four, and the first position P5 from the upstream end of the area can be estimated as the transmission position of the uplink information of the vehicle.
In addition, the beacon controller 7 can include the light reception level information about the light reception level or the light reception level ratio of each reception unit in the second downlink information 36 and transmit it to the in-vehicle device 2. In this case, the in-vehicle device 2 can perform distance recognition more accurately by correcting the distance information using the light reception level information in the correction unit 31 (FIG. 4).

[Third Embodiment]
FIG. 8 is a side view showing the communication area A of the optical beacon 4 according to the third embodiment of the present invention. In the present embodiment, the plurality of divided areas UA1 to UA4 constituting the uplink area UA are set to overlap with the other adjacent divided areas UA1 to UA4 in the vehicle traveling direction. In this embodiment, distance recognition is performed using distance information by the same method as in the first embodiment.
In the case of the present embodiment, as described in the second embodiment, it is considered that there are many cases where the uplink information 35 is simultaneously received by the two photosensors 11. Therefore, in the present embodiment, positions on the road R (for example, center positions in the vehicle traveling direction) f1, f2, and f3 in the overlapping areas VA1 to VA3 of the divided areas UA1 to UA4 are set as the upstream ends, and the predetermined position P0 is set as the downstream. Information on the distance as the end is also stored in advance in the storage device of the beacon controller 7. When the uplink information 35 is received by the two photosensors 11, the beacon controller 7 positions f1 to f3 in the overlapping area VA of the two divided areas UA1 to UA4 corresponding to the two photosensors 11. Is selected as the upstream end, and is included in the second downlink information 36.

  Also in this embodiment, the choice of distance information increases, and the vehicle-mounted device 2 can recognize a more accurate distance to the predetermined position P0. Therefore, safe driving support for the driver can be performed with higher accuracy.

  In the present embodiment, when two photosensors 11 receive the uplink information 35 in any one of the overlapping areas VA1 to VA3, the vehicle C is compared by comparing the light reception levels of the two photosensors 11. The beacon controller 7 is provided with an estimation unit that estimates at which point in the overlapping areas VA1 to VA3 the uplink information 35 is transmitted, and the upstream end of the distance information is set based on the estimated point. This distance information can be included in the second downlink information 36.

  For example, as shown for the divided areas UA3 and UA4 in FIG. 9, when uplink information is simultaneously received by the photosensors 11 (third and fourth receiving sections) corresponding to the divided areas U3 and UA4, the third receiving section If the received light level of the fourth receiver is low, the estimating unit transmits the uplink information at a position closer to the upstream side (close to the divided area U3) of the overlapping area VA3. Presumed to have been sent.

Further, the estimation unit can estimate the transmission position of the uplink information of the vehicle after allocating the area length of the overlapping area VA3 according to the ratio of the received light level.
Specifically, when the light receiving level of the third receiving unit is 3.0 μW / cm 2 and the light receiving level of the fourth receiving unit is 1.0 μW / cm 2, they overlap based on the ratio (3: 1) of both light receiving levels. The area length of the area VA3 is divided into four equal parts, and the first position P6 from the upstream end of the area VA3 is estimated as the transmission position of the uplink information of the vehicle.
In addition, the beacon controller 7 can include the light reception level information about the light reception level or the light reception level ratio of each reception unit in the second downlink information 36 and transmit it to the in-vehicle device 2. In this case, the in-vehicle device 2 can perform distance recognition more accurately by correcting the distance information using the light reception level information in the correction unit 31 (FIG. 4).

[Fourth Embodiment]
FIG. 10 is a side view showing the communication area A of the optical beacon 4 according to the fourth embodiment of the present invention. In this 4th Embodiment, the distance information memorize | stored in the memory | storage device of the beacon controller 7 is 1st distance information about the distance L0 from the most upstream end c of the uplink area | region UA to the predetermined position P0 of the downstream side. And second distance information on the distances L1 ′ to L4 ′ from the most upstream end c of the uplink area UA to the predetermined positions P1 to P4 in each of the divided areas UA1 to UA4. Then, the beacon controller 7 stores the first distance information and the second distance information corresponding to the photosensor 11 that has received the uplink information 35 in the transmission frame of the second downlink information 36, and A transmission frame is repeatedly transmitted from the beacon head 8.

When the in-vehicle head 27 receives the second downlink information 36, the distance recognition unit 30 of the in-vehicle computer 26 receives the first distance included in the transmission frame of the downlink information 36 as shown in FIG. Information and second distance information are extracted, and actual distances L1 to L4 (FIG. 10) are calculated from these first and second distance information. That is, the calculation is performed by subtracting the distances L1 ′ to L4 ′ constituting the second distance information from the distance L0 constituting the first distance information.
And the assistance control part 32 of the vehicle-mounted computer 26 performs the safe driving assistance with respect to a driver using the real distance L1-L4.

Therefore, the same effects as those of the first embodiment can be obtained in this embodiment.
Also in the present embodiment, when the uplink information 35 is simultaneously received by the two photosensors 11, the most upstream end c of the uplink area UA can be controlled so that the same control as in the second embodiment can be performed. Is stored in advance in the storage device of the beacon controller 7 as second distance information with respect to the distance having the upstream ends and the boundary positions e1, e2, e3 on the road R of the divided areas UA1 to UA4 as the downstream ends. You may keep it.

  In the present embodiment, for example, identification numbers are assigned to all of the distances L1 ′ to L4 ′, and all the distances L1 to L4 and the corresponding identification numbers are included in the second downlink information. At the same time, one identification number corresponding to the photosensor 11 that received the uplink information 35 may be included in the second downlink information 36. In this case, the distance recognition unit 30 of the in-vehicle computer 26 selects the corresponding distance from the distances L1 ′ to L4 ′ based on the identification number 1 included in the second downlink information 36, and The actual distance to the predetermined position P0 can be recognized by subtracting the distance from the distance L0.

The present invention is not limited to the above embodiments.
For example, as shown in FIG. 3, the positions of the upstream ends P1 to P4 of the distances L1 to L4 constituting the distance information are not limited to the approximate center positions on the road R of the divided areas UA1 to UA4, and are arbitrarily set. Can do. For example, the upstream ends P1 to P4 are set to the upstream ends (positions indicated by c, e1, e2, and e3) of the divided areas UA1 to UA4 on the road R, or on the road R of the divided areas UA1 to UA4. It can be set at the downstream end (position indicated by e1, e2, e3, b).

Further, the number of divided areas UA1 to UA4 (number of photosensors 11) may be two, three, or five or more.
Further, the photosensor 11 can logically divide the reception area into a plurality of areas, thereby making each a reception unit. That is, one photosensor 11 can have a plurality of receiving units. Then, these receiving units can be made to correspond to the divided areas UA1 to UA4 on the road, respectively, and distance information can be selected according to which area of the photosensor 11 is irradiated with the uplink light. In this case, it is possible to correspond to all the divided areas by using the photosensors 11 smaller than the number of the divided areas.

About the downstream end of distance L1-L4 which comprises distance information, it is good also as the installation position of a traffic light, and the position of a vehicle detector other than the stop line 40. FIG.
Further, the distance information in each of the above embodiments is not limited to a format that directly stores a distance value to the predetermined position P0, and any format may be used as long as the information can uniquely determine the distance to the predetermined position P0. There may be.

  For example, one or a plurality of nodes may be set between the uplink area UA and a predetermined position P0 on the downstream side, and the distance information may be configured by a plurality of distance value groups corresponding to these nodes. For example, a distance from a predetermined position (for example, upstream end c of the uplink area UA) to the nearest node in the uplink area UA that is the starting point, a distance between the nodes, and a predetermined position from the node nearest to the predetermined position P0 The distance information can be configured by the distance to P0. In this case, the in-vehicle computer 26 that has received the distance information can recognize the distance to the predetermined position P0 by obtaining the total value of the distances.

Further, the distance information transmitted by the optical beacon 4 is not the distance value, but the absolute position (latitude / longitude or a coordinate value in a three-dimensional space with an arbitrary point in outer space as the origin) of the distance. Etc.). For example, the distance information is configured to include information related to the absolute position in the uplink area UA obtained by the present invention and information related to the absolute position of the predetermined position P0. The distance recognition unit 30 may calculate the distance. Moreover, when the information regarding the absolute position of the predetermined position P0 is stored on the in-vehicle device 2 side, the optical beacon 4 may transmit only the information regarding the absolute position in the uplink area UA obtained by the present invention. Good.
Further, the road shape information and detailed map information indicating the shape of the road including the point of the predetermined position P0, and the position on the road or the map and corresponding to the position in the uplink area UA obtained by the present invention A method in which the optical beacon 4 transmits information and the in-vehicle device 2 acquires the distance to the predetermined position P0 based on this information may be used. In this case, road shape information and map information may be stored in the in-vehicle device 2 in advance, or may be transmitted to the in-vehicle device 2 by wireless communication other than the optical beacon 4.

Furthermore, each function part 30,31,32 of the vehicle-mounted computer 26 can also be integrated in the electronic controller (ECU) of the vehicle C.
In each of the above embodiments, the communication area A (particularly, the uplink area UA) has been described as being wider than the “near infrared interface standard” of the optical beacon, but the communication area A conforms to the standard. It may be set to a dimension.

2 In-vehicle device 4 Optical beacon 7 Beacon controller (communication controller)
8 Beacon head (emitter / receiver)
10 Light emitting diode (LED)
11 Photosensor (receiver)
30 Distance recognition unit 35 Uplink information 36 Second downlink information A Communication area C Vehicle R Road P0 Stop line (predetermined position)
DA Downlink area UA Uplink area UA1-UA4 Divided area

Claims (11)

An optical beacon having a projector / receiver in which a communication area composed of an uplink area capable of receiving uplink information and a downlink area capable of transmitting downlink information is set to a predetermined range of the road, and mounted on a vehicle A vehicle-to-vehicle communication system comprising: an in-vehicle device that transmits and receives the uplink information and the downlink information to and from the projector / receiver in the communication area,
The uplink region is divided into a plurality of divided regions in the vehicle traveling direction,
The light emitter / receiver has a plurality of receiving units for receiving the uplink information corresponding to the divided areas,
The optical beacon has a communication control unit that transmits predetermined downlink information to the projector / receiver after receiving uplink information by the receiving unit,
When the uplink information is simultaneously received by two reception units corresponding to two adjacent divided areas, the predetermined downlink information relates to a distance from the boundary between the two divided areas to the predetermined position. A road-to-vehicle communication system characterized by including distance information. The optical beacon has an estimation unit that estimates the position of the vehicle at the boundary based on the light reception levels of two reception units that simultaneously receive the uplink information;
The road-to-vehicle communication system according to claim 1, wherein the predetermined downlink information includes the distance information in which an upstream end is set based on the position of the vehicle estimated by the estimation unit. An optical beacon having a projector / receiver in which a communication area composed of an uplink area capable of receiving uplink information and a downlink area capable of transmitting downlink information is set to a predetermined range of the road, and mounted on a vehicle A vehicle-to-vehicle communication system comprising: an in-vehicle device that transmits and receives the uplink information and the downlink information to and from the projector / receiver in the communication area,
The uplink region is divided into a plurality of divided regions in the vehicle traveling direction,
The light emitter / receiver has a plurality of receiving units for receiving the uplink information corresponding to the divided areas,
The optical beacon has a communication control unit that transmits predetermined downlink information to the projector / receiver after receiving uplink information by the receiving unit,
The uplink region includes a divided region having a region overlapping with another divided region adjacent in the vehicle traveling direction,
When the uplink information is simultaneously received by two receiving units corresponding to two overlapping regions that overlap each other, the predetermined downlink information is transmitted from a position in the overlapping region to the predetermined position in the two divided regions. A road-to-vehicle communication system characterized in that it includes distance information regarding the distance of the vehicle. The optical beacon has an estimation unit that estimates the position of the vehicle in the overlapping area based on the light reception levels of two reception units that simultaneously receive the uplink information;
The road-to-vehicle communication system according to claim 3, wherein the predetermined downlink information includes the distance information in which an upstream end is set based on the position of the vehicle estimated by the estimation unit. A transmitter / receiver in which a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted is set within a predetermined range of the road, and a predetermined downlink after receiving uplink information. A communication control unit that transmits link information to the projector / receiver, and an optical beacon comprising:
The uplink region is divided into a plurality of divided regions in the vehicle traveling direction,
The light emitter / receiver has a plurality of receiving units for receiving the uplink information corresponding to the divided areas,
When the uplink information is simultaneously received by two reception units corresponding to two adjacent divided areas, the predetermined downlink information relates to a distance from the boundary between the two divided areas to the predetermined position. An optical beacon characterized by including distance information. Further comprising an estimation unit that estimates the position of the vehicle at the boundary based on the light reception levels of the two reception units that simultaneously receive the uplink information;
The optical beacon according to claim 5, wherein the predetermined downlink information includes the distance information in which an upstream end is set based on the position of the vehicle estimated by the estimation unit. A transmitter / receiver in which a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted is set within a predetermined range of the road, and a predetermined downlink after receiving uplink information. A communication control unit that transmits link information to the projector / receiver, and an optical beacon comprising:
The uplink region is divided into a plurality of divided regions in the vehicle traveling direction,
The light emitter / receiver has a plurality of receiving units for receiving the uplink information corresponding to the divided areas,
The uplink region includes a divided region having a region overlapping with another divided region adjacent in the vehicle traveling direction,
When the uplink information is simultaneously received by two receiving units corresponding to two overlapping regions that overlap each other, the predetermined downlink information is transmitted from a position within the overlapping region of the two divided regions to the predetermined position. An optical beacon characterized in that it contains distance information regarding the distance. Further comprising an estimation unit that estimates the position of the vehicle in the overlapping region based on the light reception levels of the two reception units that simultaneously receive the uplink information;
The optical beacon according to claim 7, wherein the predetermined downlink information includes the distance information in which an upstream end is set based on the position of the vehicle estimated by the estimation unit. A projector / receiver having a plurality of receiving units for receiving uplink information corresponding to a plurality of divided areas obtained by dividing the uplink area in the vehicle traveling direction;
When the two reception units corresponding to the two divided areas adjacent to each other or overlapping each other receive the uplink information at the same time, the position of the boundary between the two divided areas or the position in the overlapping area is determined as the uplink information. A beacon controller as a transmission position of
An optical beacon characterized by comprising:   The optical beacon according to claim 9, wherein the beacon controller estimates a transmission position of the uplink information in the boundary portion or an overlapping region based on a light reception level of two reception units that simultaneously receive the uplink information. .   10. The light according to claim 9, wherein the beacon controller includes, in predetermined downlink information to be transmitted after receiving the uplink information, a light reception level or a level ratio of the two reception units that simultaneously receive the uplink information. beacon.

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