JP5034853B2 - Road-to-vehicle communication system, road-to-vehicle communication method, and in-vehicle device and vehicle used therefor - Google Patents

Description

  The present invention relates to a road-to-vehicle communication system and a road-to-vehicle communication method for performing bidirectional communication using an optical signal between an optical beacon installed on a road side and an in-vehicle device mounted on the vehicle, and the in-vehicle device and the vehicle used therefor It is about.

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. 15, the beacon head (projector / receiver) 8 of the optical beacon 4 normally has a communication area A set on the upstream side rather than immediately below. According to the “near infrared interface standard” of the optical beacon (optical vehicle sensor) 8, the uplink area UA overlaps with the upstream part (right side part in FIG. 15) of the downlink area DA in the vehicle traveling direction, The upstream ends of the downlink area DA and the uplink area UA are made to coincide with each other.

  Therefore, the vehicle traveling direction length of the downlink area DA matches the same direction length of the entire communication area A. Moreover, according to the said standard, in the case of the optical beacon 4 for general roads, 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 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.

However, in practice, the currently set upstream end of the downlink area DA is often set on the upstream side (for example, c ′ in FIG. 14) with respect to the upstream end c of the uplink area UA.
JP 2005-268925 A

In the road-to-vehicle communication system, the following bidirectional communication is performed between the optical beacon 4 and the vehicle-mounted device 2 in the communication area A.
First, the optical beacon 4 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 C enters the downlink area DA, the projector / receiver (vehicle-mounted head) of the vehicle-mounted device 2 mounted on the vehicle C receives the first downlink information, and the vehicle-mounted device 2 has its own vehicle ID. Transmission of the uplink information 35 in which is stored.

When the beacon head 8 of the optical beacon 4 receives the uplink information 35, the optical beacon 4 performs downlink switching, and the second down including the lane notification information having the vehicle ID with respect to the in-vehicle device 2. Transmission of the link information 36 is started. The second downlink information 36 is repeatedly transmitted as much as possible within a predetermined time and is received by the in-vehicle device 2.
By the way, the present applicant has already proposed a driving support system that performs safe driving support to a driver using the road-to-vehicle communication system (see Japanese Patent Application Nos. 2006-121700 and 2007-20910).

In this driving support system, for example, as shown in FIG. 15, the optical beacon 4 has a predetermined downstream position from a starting point position P <b> 1 determined so as to correspond to the traveling position of the vehicle C when the uplink information 35 is transmitted. The distance L1 to the position P0 is stored, and this distance L1 is included in the second downlink information 36 and transmitted to the in-vehicle device 2.
Then, the in-vehicle device 2 that has received the second downlink information 36 determines whether or not the vehicle C can be appropriately stopped at the stop line 40 based on the distance L1 and the vehicle speed, and before the stop line 40. The vehicle C is braked so as to be forcibly stopped, or the driver is instructed to stop or decelerate to provide safe driving assistance to the driver.

However, when such a driving assistance system is adopted, there are the following problems.
That is, in order to make the distance L1 notified by the second downlink information 36 coincide with the traveling distance of the vehicle C that actually travels on the road R, the starting point position P1 of the distance L1 is the transmission of the uplink information 35. The actual travel position of the vehicle C at the time needs to be associated as accurately as possible. Therefore, the starting point position P1 is defined as the vicinity of the starting point c of the communication area A as shown in FIG.

This is because the first uplink information 35 transmitted by the in-vehicle device 2 is normally received by the optical beacon 2 with a very high probability (approximately 90% or more), so the vehicle at the time of transmission of the first uplink information 35 This is because the traveling position of C most accurately represents the relative positional relationship with the communication area A.
The start point P1 of the distance L1 provided by the infrastructure side is that the vehicle C is traveling substantially parallel to the traveling surface of the road R, and the angle in the pitch direction of the in-vehicle head 27 of the in-vehicle device 2 is that of the road R. Although it is defined on the premise that it is always constant with respect to the surface, in reality, the angle in the pitch direction of the in-vehicle head 17 always fluctuates due to the shaking of the vehicle C during traveling. The starting point position P1 of the distance L1 defined in (1) may not correspond to the actual traveling position of the vehicle C, and the distance L1 may not match the actual traveling distance of the vehicle C.

That is, the actual vehicle C does not necessarily travel parallel to the traveling surface of the road R due to the uneven state of the road R, the load of the luggage or passengers, the acceleration / deceleration conditions, etc., and the fluctuation range is about ± 5 degrees. And traveling on the road R while changing the inclination in the pitch direction.
For this reason, for example, as indicated by a broken line in FIG. 15, the vehicle C passes through the vicinity of the start point c of the communication area A in a state where the vehicle C is inclined backward by Δφ with respect to the traveling surface of the road R. U may also be transmitted at an angle larger by Δφ than the predetermined transmission angle φ.

  As described above, when the transmission angle φ of the uplink light U is shifted upward, even if the vehicle C (on-vehicle device 2) has actually reached the predetermined start position P0, the up-link from the on-vehicle device 2 is increased. The link light U may not be received by the photo sensor 11 of the optical beacon 4 and the reception timing of the uplink information 35 may be delayed. Therefore, in this case, the distance L1 notified by the second downlink information 36 from the optical beacon 4 becomes longer than the actual travel distance of the vehicle C, and the accuracy of distance recognition by the in-vehicle device 2 is increased. Will drop.

  When the accuracy of the distance L1 is reduced as described above, the accuracy of the safe driving support using the distance L1 is similarly reduced. For example, the driving is stopped before the stop line 40 by the safe driving support function. Although the vehicle is braked so as to cause the vehicle to stop, the stop line 40 may be exceeded and the vehicle may stop.

  In view of such a situation, the present invention provides a road-to-vehicle communication system and a road-to-vehicle communication method capable of accurately performing safe driving support for a driver even when the vehicle is tilted in the pitch direction. An object is to provide a machine and a vehicle.

A first road-to-vehicle communication system of the present invention (Claim 1) is a projector / receiver in which a vehicle-mounted device of a vehicle traveling on a road and a communication area composed of an uplink area and a downlink area are set to a predetermined range of the road. A roadside-to-vehicle communication system in which the in-vehicle device transmits uplink information in the uplink region, and the light projector / receiver transmits downlink information in the downlink region,
The light emitter / receiver has a receiving unit for receiving uplink information transmitted by the in-vehicle device in the uplink region,
The optical beacon causes the projector / receiver to transmit downlink information including distance information regarding a distance from a start position corresponding to the travel position of the vehicle at the time of transmission of uplink information to a predetermined position downstream thereof. Having a communication control unit,
The vehicle device has a tilt detection means for detecting the pitch direction of inclination of the vehicle relative to the running surface of the road at the time of transmission of the uplink information, by correcting the distance information based on the come detected tilt A distance recognizing unit for obtaining the distance.

According to the first road-to-vehicle communication system, the communication control unit of the optical beacon transmits downlink information including distance information regarding the distance from the start position in the uplink region to a predetermined position on the downstream side to the projector / receiver. Since it transmits, the vehicle equipment which received the downlink information can obtain | require the distance to the predetermined position downstream of a communication area using the said distance information.
Then, the inclination detecting means of the vehicle-mounted machine, detects the inclination in the pitch direction of the vehicle relative to the running surface of the road at the time of transmission of the uplink information, distance identification of the vehicle unit is to come the detected inclination Since the distance information is corrected based on the distance, the distance can be determined accurately even if the vehicle is tilted in the pitch direction, and safe driving support for the driver can be accurately performed.

  In the first road-to-vehicle communication system (Claim 1), when the uplink region is a non-divided reception region by one receiving unit (non-division type: fifth embodiment), the uplink region is a vehicle traveling When the optical beacon projector / receiver has a plurality of receiving units that receive uplink information corresponding to each divided region (division type: first to fourth implementations). Form) and both.

The second road-to-vehicle communication system of the present invention (Claim 2) relates to a case where the uplink region is the above-mentioned division type (first to fourth embodiments).
In the second road-to-vehicle communication system (Claim 2), the optical beacon is a distance from a start position in the divided area corresponding to the receiving unit that has received uplink information to a predetermined position downstream thereof. Although the communication control unit that transmits the downlink information including the distance information to the projector / receiver is included, the configuration on the vehicle-mounted device side is the same as that of the first road-to-vehicle communication system (Claim 1). is there.

Therefore, also in the second road-to-vehicle communication system, the distance can be accurately obtained even if the vehicle is tilted in the pitch direction, and safe driving support for the driver can be accurately performed.
In the road-to-vehicle communication system (first to fourth embodiments) that employs the division type uplink region, the vehicle traveling direction length of the region is set to be large as a whole so that uplink information can be easily received. In addition, the length in the vehicle traveling direction of each divided region can be set to be relatively small. Accordingly, there is an advantage that the starting point position of the distance corresponding to each divided region is not greatly separated from the actual traveling position of the vehicle, and the distance to the predetermined position can be accurately recognized in the in-vehicle device.

In the road-to-vehicle communication system of the present invention (claims 1 and 2), as described in an embodiment described later, a gyro sensor, a G sensor, an acceleration sensor, and the like are used as the inclination detection means for detecting the inclination in the pitch direction of the vehicle. can do.
However, since the inclination in the pitch direction detected by these sensors is based on the horizontal plane, not the road running surface, it is detected by these sensors when the road running surface itself is inclined. The slope that is applied is not the slope from the road running surface.

Therefore, in the road-to-vehicle communication system of the present invention, the communication control unit employs a transmission that includes gradient information related to a road gradient in the uplink region included in the downlink information, and the distance recognition unit, Preferably, the distance is corrected by correcting the distance information based on the inclination detected by the inclination detecting means and the gradient information.
In this case, more specifically, the inclination in the pitch direction of the vehicle based on the road running surface can be obtained by canceling out the inclination detected by the inclination detecting means with the road gradient in the uplink region. Therefore, even when there is a road gradient in the uplink region, the distance to the predetermined position can be accurately corrected.
As will be described later, in the road-to-vehicle communication system of the present invention, specifically, the inclination detecting means employs a sensor device including at least two of a gyro sensor, a G sensor, and an acceleration sensor. (Claim 4).

The first vehicle-mounted device (Claim 5) of the present invention is used in the first road-to-vehicle communication system (Claim 1), and has the same effects as the system.
Moreover, the 2nd vehicle equipment (Claim 6) of this invention is used for a said 2nd road-vehicle communication system (Claim 2), and there exists an effect similar to the system.
A first road-to-vehicle communication method (Claim 7) of the present invention is a communication method performed in the first road-to-vehicle communication system (Claim 1), and has the same effects as the system.
The second road-to-vehicle communication method (Claim 8) of the present invention is a communication method performed in the second road-to-vehicle communication system (Claim 2), and has the same effects as the system.

  As described above, according to the present invention, the distance to a predetermined position on the downstream side of the communication area can be accurately obtained even when the vehicle is tilted in the pitch direction, and safe driving support for the driver is accurately performed. be able to.

[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 in the illustrated example) of photo sensors 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.
Accordingly, 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. Accordingly, the total length of the official communication area A in the vehicle traveling direction (the length between ac) 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 of the present embodiment 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. Yes.
The four photosensors 11 (see 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 35 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) 27A (see FIG. 3) and a photosensor (not shown), similar to the light beacon projector / receiver 8. Among these, the LED 27A 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.

The in-vehicle device 2 includes an inclination detector (inclination detecting means) 33 that detects an inclination of the vehicle C in the pitch direction. The inclination detector 33 uses a gyro sensor, a G sensor, or an acceleration sensor. The degree of inclination of the vehicle C with respect to the horizontal plane in the pitch direction is constantly monitored.
The gyro sensor is a sensor that measures the angular velocity of an object, and an angle (tilt) can be obtained by integrating the detection signal. The G sensor is a sensor that measures the acceleration of an object, and gravitational acceleration is also added to the G sensor. On the other hand, an acceleration sensor is often synonymous with a G sensor. In this specification, an acceleration sensor that senses only an acceleration component having frequency characteristics and does not sense static acceleration (gravity acceleration) is called an acceleration sensor. .

FIG. 8 is an explanatory diagram showing the principle of detection of the inclination of the vehicle C that can be implemented by the sensor.
Among these, Fig.8 (a) has shown the detection principle of the inclination detector 33 which combined the triaxial G sensor and the triaxial acceleration sensor.
When the object is placed on the horizontal plane, the output of the 3G sensor is gz = G (G: gravitational acceleration), gx = gy = 0, but when the object is tilted from the horizontal plane, gz <G and gx ≠ 0 or gy ≠ 0. Therefore, the inclination of the object with respect to the horizontal plane can be calculated by using the ratio of gz to the other gx, gy among the three outputs of the 3G sensor.

However, when dynamic acceleration is generated in the object, such as when the vehicle C is accelerating, the dynamic acceleration is superimposed on gx, gy, and gz. Therefore, a triaxial acceleration sensor that does not detect gravitational acceleration (static acceleration) is used at the same time.
That is, if the output in each direction of the triaxial acceleration sensor is ax, ay, az, the output component is subtracted in each direction, and the ratio of (gx-ax), (gy-ay), (gz-az) The absolute value of the inclination of the object in the pitch direction with respect to the horizontal plane can be calculated by the following equation (1) using.

As for the direction of the inclination in the pitch direction, it can be determined whether the front of the vehicle C is upward or downward with respect to the horizontal plane by the sign of (gy-ay).
It should be noted that the absolute value of the inclination in the pitch direction can be simply obtained using only the value of (gz-az) using a single-axis G sensor and a single-axis acceleration sensor.

FIG. 8B shows the detection principle of the inclination detector 33 that combines a one-axis gyro sensor and a one-axis or three-axis acceleration sensor.
If the single-axis gyro sensor detects the angular velocity in the direction of the arrow in FIG. 8B with the horizontal plane as the base point, the inclination in the pitch direction of the object with respect to the horizontal plane can be detected by integrating the angular velocity. However, since errors accumulate in the integrated value over time, it is necessary to periodically perform zero point correction.

Therefore, the 1-axis, 2-axis or 3-axis G sensor is used simultaneously. That is, in this case, the output of the G sensor is monitored, and when the output is gz = G (and gx = gy = 0) and the value is stable, it is determined that the object is stable in the horizontal state, and the gyro What is necessary is just to correct | amend the zero point of the output of a sensor.
In addition, as another example of the inclination detector 33, it can also be comprised from the vehicle-mounted camera which images the road R, and the image processing apparatus which analyzes the imaged image data and calculates | requires the relative inclination with respect to the road R. .

[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.
The support information includes signal information that is timing information for changing the color of the traffic light downstream from the optical beacon 4 and a predetermined position P0 (downstream from a predetermined start position P1 to P4 in the uplink area UA. For example, distance information regarding length information L1 to L4 to the stop line 40) and gradient information regarding the road gradient of the uplink area UA are 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 switching of the downlink in the optical beacon 4 at the time of receiving the second downlink information 36 (F7 in FIG. 5), and at this time, transmits the uplink information 35. Stop.

As shown in FIG. 3, the road-to-vehicle communication system according to the present embodiment allows the vehicle-mounted device 2 to recognize the distance from the start position P1 to P4 of the communication area A defined by the infrastructure side to the predetermined position P0 on the downstream side. It functions as a distance recognition system that performs orientation (F8 in FIG. 5) and provides safe driving support to the driver based on this.
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 end point position (downstream end) 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.

In addition, start positions (upstream ends) P1 to P4 of the distances L1 to L4 are set at four locations according to the divided areas UA1 to UA4 of the uplink area UA.
The starting point positions of the distances L1 to L4 need to be associated with the actual traveling position of the vehicle C at the time of transmission of the uplink information 35 as accurately as possible. However, in this embodiment, the uplink area UA is more than the vehicle C. Since it is divided into four divided areas UA1 to UA4 having a small length in the vehicle traveling direction, it is set at a substantially central position in the vehicle traveling direction on the road R in each divided area UA1 to UA4.

The beacon controller 7 selects one of the distance information regarding the plurality of distances L1 to L4 stored in advance, and stores it in the transmission frame of the second downlink information 36. Which distances L1 to L4 are selected by the beacon controller 7 is determined based on which photosensor (reception unit) 11 has received the uplink information 35 before switching the downlink.
For example, as shown in FIG. 6, when the photo sensor (first receiving unit) 11 corresponding to the most upstream divided area UA1 receives the uplink information 35, the beacon controller (downlink switching control unit) 7 The photo sensor 11 that has received the uplink information 35 is identified, the corresponding distance information L1 is selected, the downlink is switched, and the second downlink information 36 that includes the distance information about the distance L1 via the LED 10 is selected. Is transmitted to the in-vehicle device 2.

  On the other hand, even 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 still has the start point positions P2 to P4. Are selected, and the second downlink information 36 including the distance information about the distances L2 to L4 is transmitted to the in-vehicle device 2.

[Contents of distance recognition (safe driving support)]
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 extracts the distance information included in the frame of the downlink information 36, and Recognize the distances L1 to L4.
By the way, the start positions P1 to P4 of the distances L1 to L4 provided by the infrastructure-side optical beacon 4 are such that the vehicle C travels substantially parallel to the traveling surface of the road R, and the in-vehicle head 27 of the in-vehicle device 2 It is defined on the assumption that the angle in the pitch direction is always constant with respect to the traveling surface of the road R.

However, in reality, the actual vehicle C does not necessarily travel parallel to the traveling surface of the road R due to the uneven state of the road R, the load of the luggage or passengers, the acceleration / deceleration conditions, and the like. The vehicle travels on the road R while changing the inclination in the pitch direction within a fluctuation range of about ± 5 degrees.
For this reason, the starting point positions P1 to P4 of the distances L1 to L4 defined on the infrastructure side may not correspond to the actual travel position of the vehicle C, and the distances L1 to L4 may not match the actual travel distance of the vehicle C. .

For example, as shown in FIG. 7, the photosensors 11 corresponding to the divided areas UA1 to UA4 are respectively 11A to 11D, and when the vehicle C reaches a certain position α, the second photosensor 11B receives the uplink light U. Assume that the position of the third photosensor 11C is set so as to receive the uplink light U when it reaches another position β.
In this case, as shown in the lowermost stage in FIG. 7, when the vehicle C passes through the position α in a state where the vehicle C is inclined downward by Δφ with respect to the traveling surface of the road R, the uplink light U is also transmitted in a predetermined manner. It is transmitted at an angle smaller than the angle φ by Δφ.

Depending on the magnitude of the deviation angle Δφ, the uplink light U from the vehicle C at the position α may reach the third photosensor 11C corresponding to the position β on the downstream side.
In this way, when the transmission angle φ of the uplink light U deviates downward, the uplink light U reaches the position β downstream of the actual position α of the vehicle C (onboard unit 2), and the uplink light U The reception location of the information 35 may precede.

Therefore, in this case, the distance L3 notified by the second downlink information 36 from the optical beacon 4 becomes shorter than the actual travel distance of the vehicle C, and the accuracy of distance recognition in the in-vehicle device 2 is increased. Will drop.
Note that when the vehicle C is tilted backward by Δφ with respect to the traveling surface of the road R, the transmission angle φ of the uplink light U is shifted upward by Δφ. There is a risk that the photo sensor 11B uplink light U corresponding to the position α on the upstream side of the actual position β will reach and the reception location of the uplink information 35 will be retracted.

Therefore, in the present embodiment, the in-vehicle computer 26 stores the output value of the inclination detector 33 (the inclination in the pitch direction of the vehicle C with respect to the horizontal direction) when the uplink information 35 is transmitted, and based on this inclination. The correction unit 31 of the computer 26 calculates a correction value of the values of the distances L1 to L4 extracted from the second downlink information 36.
Further, the correction unit 31 of the in-vehicle computer 26 extracts the “gradient information” of the uplink area UA from the second downlink information 36, and specifies the inclination (Δφ) detected by the inclination detector 33 by the inclination information. The slope in the pitch direction of the vehicle C with respect to the traveling surface of the road R is obtained by offsetting the road gradient in the uplink area UA.

Specifically, the correction unit 31 calculates a distance error in the vehicle traveling direction caused by the inclination in the pitch direction of the vehicle C with respect to the traveling surface of the road R using a predetermined geometric formula, and calculates the distance error on the in-vehicle computer. It outputs to 26 distance recognition parts 30.
Note that when the “gradient information” is not included in the downlink information 36, the correcting unit 31 uses the output value (Δφ) of the slope detector 33 as a reference for the road R on the road R. The distance error is calculated by regarding the inclination as a direction.

Then, the distance recognizing unit 30 compares the distance error with a predetermined threshold value. If the distance error is larger than the threshold value, the distance recognition unit 30 adds the distance error to the distance information regarding the distances L1 to L4 obtained from the downlink information 36. Alternatively, the actual distances L1 to L4 are obtained by subtraction.
The support control unit 32 of the in-vehicle computer 26 performs safe driving support for the driver using the distances L1 to L4 corrected as described above.

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 L1-L4.

  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 26 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.
Further, 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 .

Note that the signal information may be only the currently displayed lamp color and its duration, or information for one cycle may be provided collectively. 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 inclination detector 33 of the in-vehicle device 2 detects the inclination in the pitch direction of the vehicle C when the uplink information 35 is transmitted, and the in-vehicle device Since the distance recognition unit 30 of No. 2 corrects the distance information based on the detected inclination to obtain the distances L1 to L4, the distances L1 to L4 are accurately obtained even if the inclination in the pitch direction occurs in the vehicle. Therefore, safe driving support for the driver can be performed with high accuracy.

  Moreover, 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 includes a plurality of photosensors 11 corresponding to the divided areas UA1 to UA4. Is selected, and distances L1 to L4 to the 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. Even if the entire uplink area UA is set wider in the vehicle traveling direction than prescribed, the starting positions P1 to P4 of the distances L1 to L4 and the actual position of the vehicle C (onboard unit 2) are greatly separated. There is almost nothing.

For this reason, the in-vehicle device 2 can accurately recognize the distance to the predetermined position P0, and 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 according to the present embodiment is also useful in that the distance to the predetermined position P0 can be recognized with high accuracy 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 rain and fog that light that transmits uplink information (uplink light) is difficult to reach the beacon head 8, vehicle C The condition is such that the uplink light is blocked by operating the wiper.
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 downlink switching. 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 present 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 one identification number corresponding to the photosensor 11 that has received the uplink information 35 is used as the second downlink information. 36 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 line (boundary part) 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.
Note that the in-vehicle device 2 corrects the distance information obtained from the second downlink information 36 based on the inclination in the pitch direction of the vehicle at the time of transmission of the uplink information detected by the inclination detector 33, and the actual distance The point which calculates | requires L1-L4 is the same as that of 1st Embodiment.

In the present embodiment, the boundary line (boundary portion) K can be assumed to have a predetermined width.
For example, as shown in FIG. 9 for the divided areas UA3 and UA4, there are two predetermined widths in the vicinity of the downstream end of the divided area UA3 and the vicinity of the upstream end of the divided area UA4 and 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. 10 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 upstream ends, and the predetermined position P0 is set 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. 10, 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. 11 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 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. 12) are calculated from the 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, this embodiment also has the same operational effects as the first 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.

[Fifth Embodiment]
13 to 15 show a road-vehicle communication system according to a fifth embodiment of the present invention.
This embodiment is different from the first embodiment in that the uplink area UA is not divided in the vehicle traveling direction as shown in FIGS. 13 to 15 and is not divided by one photosensor (receiving unit) 11. Is in the receiving area.
Hereinafter, members having the same structure and function as those in the first embodiment will be denoted by the same reference numerals in the drawings, and the description thereof will be omitted. Only portions different from those in the first embodiment will be mainly described.

In the present embodiment, for the second downlink information 36 provided by the optical beacon 4, not only the distance information about the distance L1 from the start position P1 of the communication area A to the predetermined position P0, but also downlink switching (FIG. 5 includes transmission progress information based on the transmission of the first second downlink information 36 after performing F5) (similar to the above-mentioned Japanese Patent Application No. 2006-121700).
This transmission progress information may be an elapsed time with the transmission time of the first second downlink information 36 as a reference time, or the number of transmissions based on the transmission of the first second downlink information 36 as a reference. There may be.

In this embodiment, the distance recognition unit 30 of the in-vehicle device 2 (in-vehicle computer 26) corrects the distance L1 obtained from the distance information using the transmission progress information, and the actual distance L to the predetermined position P0 is obtained. It comes to ask for.
For example, as shown in FIG. 15, it is assumed that the in-vehicle device 2 cannot receive the first downlink information D1 among the repeatedly transmitted downlink information D1 and D2, and can receive the second downlink information D2.

In this case, the correction unit 31 of the in-vehicle device 2 receives the second downlink information D2 from the time of transmission of the uplink information 35 based on the elapsed time or the number of elapsed times included in the second downlink information. The traveling distance of the vehicle C that has traveled in the meantime is obtained as the correction value E. And the distance recognition part 30 of the vehicle equipment 2 calculates | requires the actual distance L to the downstream stop line 40 by subtracting the said correction value E from the distance L1 contained in distance information.
As described above, in the present embodiment, the in-vehicle device 2 side corrects the distance information using the transmission progress information as well as the correction of the distance error based on the fluctuation Δφ of the transmission angle φ. In this case, it is possible to eliminate an error associated with the location where the downlink information 36 is received at different locations. For this reason, the precision of distance recognition to the front stop line 40 can be improved, and driving support control with high reliability can be performed.

The present invention is not limited to the above embodiments.
For example, as shown in FIG. 3, in the division type road-to-vehicle communication system in which the uplink area UA is divided, the positions of the upstream ends P1 to P4 of the distances L1 to L4 constituting the distance information are the divided areas UA1 to UA4. It is not limited to the approximate center position on the road R, and can be arbitrarily set. 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.

  For example, as shown in Japanese Patent Application No. 2007-188019 already filed by the present applicant, a photosensor (photodiode) capable of specifying the transmission position of the uplink light based on the light reception position where the uplink light U is incident on the light receiving surface. There is. If such a photosensor is employed as the light receiving unit for the uplink light U, a plurality of distance information corresponding to each of the divided areas UA1 to UA4 is obtained by dividing the light receiving area of the photosensor corresponding to the divided areas UA1 to UA4. Can be generated by one photosensor.

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 includes not only the value of the distance itself but also position information corresponding to the distance, and the absolute position (latitude / longitude or any arbitrary space in space) of the distance. The coordinate value of the three-dimensional space with the point of the origin as the origin) can be used as the information.
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.

When the distance information is information related to the absolute position, in the in-vehicle computer 26 of the in-vehicle device 2, an operation for obtaining a formal distance after the correction unit 31 first corrects the start point position in the uplink area UA. Processing can also be adopted, and calculation processing in which the correction unit 31 corrects this distance after calculating the distance from the starting point position to the predetermined position can also be adopted.
Thus, in this specification, “correcting the distance information” includes not only correcting the distance value itself but also correcting the starting point position of the uplink area UA that is the starting end of the distance. Is.

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 an optical beacon, but the communication area A conforms to the standard. It may be set to a dimension.

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 one receiving part receives uplink information. It is explanatory drawing which shows the generation | occurrence | production principle of the distance error by the inclination of a vehicle equipment (vehicle). It is explanatory drawing which shows the detection principle of the inclination of the vehicle equipment (vehicle) by an inclination detector. It is the side view to which a part of uplink area which concerns on 2nd Embodiment of this invention was expanded. It is a side view of 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 of the communication area | region of the optical beacon which concerns on 4th Embodiment of this invention. It is a block diagram which shows the whole structure of the road-vehicle communication system which concerns on 5th Embodiment of this 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.

Explanation of symbols

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)
26 On-vehicle computer 27 On-vehicle head (emitter / receiver: receiver)
27A Light Emitting Diode (LED)
30 Distance recognition unit 31 Correction unit 32 Support control unit 33 Tilt detector (tilt detection means)
34 First downlink information 35 Uplink information 36 Second downlink information A Communication area C Vehicle R Road P0 Stop line (predetermined position)
P1 to P4 Start position DA Downlink area UA Uplink area UA1 to UA4 Divided area

Claims (11)

An in-vehicle device of a vehicle traveling on a road, and an optical beacon having a light emitter / receiver in which a communication region composed of an uplink region and a downlink region is set to a predetermined range of the road, and the in-vehicle device in the uplink region Is a road-to-vehicle communication system in which uplink information is transmitted, and in the downlink region, the projector / receiver transmits downlink information,
The light emitter / receiver has a receiving unit for receiving uplink information transmitted by the in-vehicle device in the uplink region,
The optical beacon has a communication control unit that causes the projector / receiver to transmit downlink information including distance information related to a distance from a start point position in the uplink region to a predetermined position downstream thereof,
The vehicle device has a tilt detection means for detecting the pitch direction of inclination of the vehicle relative to the running surface of the road at the time of transmission of the uplink information, by correcting the distance information based on the come detected tilt A road-to-vehicle communication system comprising: a distance recognition unit for obtaining the distance. An in-vehicle device of a vehicle traveling on a road, and an optical beacon having a light emitter / receiver in which a communication region composed of an uplink region and a downlink region is set to a predetermined range of the road, and the in-vehicle device in the uplink region Is a road-to-vehicle communication system in which uplink information is transmitted, and in the downlink region, the projector / receiver transmits downlink information,
The light emitter / receiver has a plurality of receiving units for receiving uplink information corresponding to each divided region obtained by dividing the uplink region in the vehicle traveling direction,
The optical beacon transmits, to the projector / receiver, downlink information including distance information regarding a distance from a start point position in the divided area corresponding to the reception unit that has received uplink information to a predetermined position on the downstream side. Having a communication control unit to transmit,
The in-vehicle device includes an inclination detection unit that detects an inclination of the vehicle in the pitch direction when uplink information is transmitted, and a distance recognition unit that corrects the distance information based on the detected inclination and obtains the distance. A road-to-vehicle communication system comprising: The communication control unit transmits the downlink information including the gradient information related to the road gradient in the uplink region,
The road-to-vehicle communication system according to claim 1 or 2, wherein the distance recognizing unit is configured to correct the distance information based on the inclination detected by the inclination detecting unit and the gradient information, thereby obtaining the distance.   The road-to-vehicle communication system according to any one of claims 1 to 3, wherein the inclination detection unit includes at least two of a gyro sensor, a G sensor, and an acceleration sensor. It is an in-vehicle device for a vehicle traveling on a road, and transmits uplink information to an optical beacon transmitter / receiver in which a communication region consisting of an uplink region and a downlink region is set, and downlink information is transmitted from the transmitter / receiver. In-vehicle device that receives
A receiving unit for receiving, from the projector / receiver, downlink information including distance information regarding a distance from a start point position in the uplink region to a predetermined position on the road downstream thereof;
An inclination detecting means for detecting an inclination in the pitch direction of the vehicle with reference to a road running surface at the time of transmission of uplink information;
Vehicle device, characterized in that it comprises a distance recognition unit for determining the distance by correcting the distance information based on the come detected tilt. It is an in-vehicle device for a vehicle traveling on a road, and transmits uplink information to an optical beacon transmitter / receiver in which a communication region consisting of an uplink region and a downlink region is set, and downlink information is transmitted from the transmitter / receiver. In-vehicle device that receives
Downlink information including distance information related to a distance from a starting point position set in a divided area obtained by dividing the uplink area in the vehicle traveling direction to a predetermined position on the downstream side is received from the projector / receiver. A receiver,
Inclination detecting means for detecting inclination of the vehicle in the pitch direction at the time of transmission of uplink information;
An in-vehicle device, comprising: a distance recognition unit that corrects the distance information based on the detected inclination to obtain the distance. The downlink information includes gradient information related to the road gradient in the uplink region,
The in-vehicle device according to claim 5 or 6, wherein the distance recognition unit obtains the distance by correcting the distance information based on the inclination detected by the inclination detection unit and the gradient information.   The in-vehicle device according to any one of claims 5 to 7, wherein the tilt detection unit includes at least two of a gyro sensor, a G sensor, and an acceleration sensor. An in-vehicle device mounted on a vehicle transmits uplink information to an optical beacon transmitter / receiver in an uplink region set in a predetermined range of the road, and in response to reception of the uplink information, the projector / receiver A road-to-vehicle communication method for transmitting downlink information to the in-vehicle device in a downlink region set in a predetermined range of the road,
The optical beacon transmits distance information about a distance from a start position in the uplink region to a predetermined position downstream thereof in downlink information after receiving the uplink information, and transmits the information to the in-vehicle device. ,
The vehicle device, the road-vehicle communication method, wherein the relative to the running surface of a road based on the come pitch direction tilting of the vehicle by correcting the distance information obtaining the distance. An in-vehicle device mounted on a vehicle transmits uplink information to an optical beacon transmitter / receiver in an uplink region set in a predetermined range of the road, and in response to reception of the uplink information, the projector / receiver A road-to-vehicle communication method for transmitting downlink information to the in-vehicle device in a downlink region set in a predetermined range of the road,
The optical beacon receives the uplink information, the distance information related to the distance from the start point position set in the divided area obtained by dividing the uplink area in the vehicle traveling direction to the predetermined position on the downstream side. Included in the subsequent downlink information and sent to the in-vehicle device,
The on-vehicle device corrects the distance information based on an inclination in the pitch direction of the vehicle to obtain the distance.   The vehicle carrying the vehicle equipment of any one of Claims 5-8.

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