JP2007293660A - Optical beacon, road-vehicle communication system, on-vehicle device used for the system, and distance recognition method using the system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical beacon for making a vehicle side to accurately recognize a distance to a prescribed position on a road positioned in front of a vehicle advancing direction in a communication area. <P>SOLUTION: The beacon includes a communication unit 2a having a communication area consisting of an up-link area capable of receiving up-link information and a down-link area capable of transmitting down-link information. The down-link information from the communication unit 2a includes the distance information to the prescribed position on the road positioned in front of the advancing direction of the vehicle in the communication area. A vehicle advancing direction length (a) from a starting end of the up-link area up to a final end of the down-link area is set within a range of a distance error of the prescribed position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is capable of obtaining a distance to a predetermined position located in front of a vehicle traveling direction in a communication area, an optical beacon, a road-to-vehicle communication system, an in-vehicle device used in a road-to-vehicle communication system, and The present invention relates to a distance recognition method performed using a road-vehicle communication system.

Conventionally, in order to prevent traffic accidents caused by vehicles in and near the intersection, red, yellow and blue display information of traffic lights provided at the intersection is provided in advance to the traveling vehicle and installed in the vehicle. Based on the information, the in-vehicle device can determine whether it can stop safely before the intersection, whether it can safely pass through the intersection, or urge the driver to be alerted by voice, etc. is there. And there exists a device which judges whether an in-vehicle machine can pass through an intersection safely, and performs driving control of vehicles based on the judgment (for example, refer to patent documents 1).
In the device described in Patent Document 1, for example, time information until the traffic light displaying blue turns red is transmitted from the transmission device provided on the road to the vehicle. If it is determined that there is no time to safely pass through the intersection, that is, if it is determined that the vehicle should stop before the intersection, the brake is applied automatically and the vehicle is Control is performed to decelerate and stop, and stop before the intersection.

Japanese Patent No. 2806801

In order for the vehicle to determine whether or not the vehicle should stop before the intersection, when it is determined that the vehicle should be further stopped, it can be safely stopped according to the stop line provided before the intersection In order for the vehicle side to determine whether or not, the vehicle-mounted device needs to accurately recognize the distance to the stop line. However, in the apparatus described in Patent Document 1, since the distance to the stop line cannot be accurately determined even when the vehicle is automatically decelerated, the vehicle can be appropriately stopped according to the stop line. It becomes difficult and may cause problems such as overrun. Therefore, the conventional technology is insufficient as a device for preventing an accident at an intersection.
On the other hand, the current driving position of the host vehicle can be detected by the function of the car navigation system using GPS, and the position of the intersection can be extracted from the map data of the car navigation system, so that the stop before the intersection from the current driving position. A distance to a predetermined position such as a line can be calculated. However, since the position detection error by GPS occurs on the order of several tens of meters, accurate operation control becomes difficult.

  Therefore, the present invention is used in an optical beacon, a road-to-vehicle communication system, and a road-to-vehicle communication system that can make the vehicle accurately recognize the distance to a predetermined position on the road located in front of the vehicle travel direction in the communication area. It is an object of the present invention to provide a distance recognition method performed using an in-vehicle device and a road-vehicle communication system.

  In order to achieve the above object, the present invention provides an optical beacon including a communication unit having a communication region including an uplink region in which uplink information can be received and a downlink region in which downlink information can be transmitted. The downlink information from the communication unit includes distance information to a predetermined position located forward of the communication area in the vehicle traveling direction, and the vehicle travels from the start of the uplink area to the end of the downlink area. The direction length is set within the distance error range of the predetermined position.

According to the optical beacon with this configuration, the vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is set within the distance error range of the predetermined position. Even if the vehicle side receives the distance information, the vehicle side can accurately recognize the distance to the predetermined position within the range of the distance error based on the distance information.
The “distance error at a predetermined position” means a distance error that can be considered that the vehicle is substantially at the predetermined position in relation to the vehicle dimensions. In the case of stopping (when the predetermined position is a road stop line), the normal stop distance that the driver feels that the vehicle stopped without a sense of incongruity before the predetermined position corresponds to the distance error. This normal stop distance can be set to about 2.5 m, for example, as will be described later in an embodiment.

  According to another aspect of the present invention, there is provided an optical beacon including a communication unit including a communication region including an uplink region in which uplink information can be received and a downlink region in which downlink information can be transmitted. The downlink information includes distance information to a predetermined position located in front of the communication region in the vehicle traveling direction, and the vehicle traveling direction length from the end of the uplink region to the end of the downlink region is It is set to be more than the distance obtained by the product of the transmission period of the downlink information and the maximum corresponding speed of the vehicle.

According to the optical beacon of this configuration, the vehicle traveling direction length from the end of the uplink region to the end of the downlink region is greater than the distance obtained by the product of the transmission period of the downlink information and the maximum corresponding speed of the vehicle. Since it is set, the vehicle traveling at the maximum corresponding speed can receive the downlink information for at least one period in the region from the end of the uplink region to the end of the downlink region. Accordingly, the vehicle side can reliably receive the distance information included in the downlink information, and the vehicle side can recognize the distance to the predetermined position with high accuracy based on the distance information.
The “maximum supported speed” is the maximum speed that guarantees that the vehicle side receives the distance information.
The downlink information is composed of one or a plurality of types of information, and each piece of information is composed of one or a plurality of frames. Then, the one or more frames are sequentially and repeatedly transmitted at a predetermined downlink transmission cycle. As used herein, “downlink information transmission cycle” refers to a cycle from the transmission of the first frame of the one or more frames to the transmission of the first frame again.

  Further, in this optical beacon, the vehicle traveling direction length from the end of the uplink region to the end of the downlink region is the distance obtained by the product of the transmission period of the downlink information and the maximum corresponding speed of the vehicle. It is preferably set to 1.2 times or less. In this case, the vehicle side can receive the distance information more reliably.

  According to another aspect of the present invention, there is provided an optical beacon including a communication unit including a communication region including an uplink region in which uplink information can be received and a downlink region in which downlink information can be transmitted. The downlink information includes distance information to a predetermined position located in front of the communication region in the vehicle traveling direction, and the vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is The length of the vehicle traveling direction from the end of the uplink region to the end of the downlink region is set within the distance error range of the predetermined position, and the maximum correspondence between the downlink information transmission cycle and the vehicle It is set more than the distance obtained by the product with the speed.

According to the optical beacon with this configuration, the vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is set within the distance error range of the predetermined position. Even if the vehicle side receives the distance information, the vehicle side can accurately recognize the distance to the predetermined position within the range of the distance error based on the distance information.
Furthermore, since the vehicle traveling direction length from the end of the uplink region to the end of the downlink region is set to be greater than or equal to the distance obtained by the product of the downlink information transmission cycle and the maximum corresponding speed of the vehicle, the maximum A vehicle traveling at a corresponding speed can receive downlink information for at least one period in a region from the end of the uplink region to the end of the downlink region. Accordingly, the vehicle side can reliably receive the distance information included in the downlink information, and the vehicle side can recognize the distance to the predetermined position with high accuracy based on the distance information.

  According to another aspect of the present invention, there is provided an optical beacon including a communication unit including a communication region including an uplink region in which uplink information can be received and a downlink region in which downlink information can be transmitted. The downlink information includes distance information to a predetermined position located in front of the communication region in the vehicle traveling direction, and the vehicle traveling direction length from the start of the uplink region to the end of the uplink region is It is set to be more than the distance obtained by the product of the transmission cycle of the uplink information and the maximum corresponding speed of the vehicle.

  According to this, the vehicle traveling direction length from the beginning of the uplink region to the end of the uplink region is set to be greater than or equal to the distance obtained by the product of the uplink information transmission cycle and the maximum corresponding speed of the vehicle. Therefore, the optical beacon can receive the uplink information for at least one cycle from the vehicle side that is in the uplink region and travels at the maximum corresponding speed. Thereby, the optical beacon can reliably receive the uplink information from the vehicle side, and thereafter, the optical beacon can transmit the predetermined downlink information including the distance information to the vehicle side to the vehicle side. The distance information can be received by the vehicle, and the distance to the predetermined position can be accurately recognized by the vehicle based on the distance information.

  Further, in this optical beacon, the vehicle traveling direction length from the start end of the uplink region to the end of the uplink region is the distance obtained by the product of the transmission period of the uplink information and the maximum corresponding speed of the vehicle. It is preferably set to 1.2 times or less. According to this, the optical beacon can receive the uplink information more reliably.

  According to another aspect of the present invention, there is provided an optical beacon including a communication unit including a communication region including an uplink region in which uplink information can be received and a downlink region in which downlink information can be transmitted. The downlink information includes distance information to a predetermined position located in front of the communication region in the vehicle traveling direction, and the vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is The length of the vehicle traveling direction from the start of the uplink region to the end of the uplink region is set within the distance error range of the predetermined position, and the maximum correspondence between the uplink information transmission cycle and the vehicle It is set more than the distance obtained by the product with the speed.

According to the optical beacon with this configuration, the vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is set within the distance error range of the predetermined position. Even if the vehicle side receives the distance information, the vehicle side can accurately recognize the distance to the predetermined position within the range of the distance error based on the distance information.
Furthermore, since the vehicle traveling direction length from the start end of the uplink region to the end of the uplink region is set to be more than the distance obtained by the product of the uplink information transmission period and the maximum corresponding speed of the vehicle, The optical beacon can receive uplink information for at least one period from the vehicle side that is in the uplink region and travels at the maximum corresponding speed. Thereby, the optical beacon can reliably receive the uplink information from the vehicle side, and thereafter, the optical beacon can transmit the predetermined downlink information including the distance information to the vehicle side to the vehicle side. The distance information can be received by the vehicle, and the distance to the predetermined position can be accurately recognized by the vehicle based on the distance information.

  The present invention also provides an optical beacon including a communication unit having a communication area including an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted, and the uplink in the communication area. In a road-to-vehicle communication system provided with an in-vehicle device that transmits and receives link information and downlink information, the downlink information from the communication unit of the optical beacon includes a predetermined position that is located forward of the communication region in the vehicle traveling direction. Distance information is included, and the vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is set within the range of the distance error of the predetermined position.

  And the distance recognition method performed using this road-to-vehicle communication system includes distance information to a predetermined position located forward in the vehicle traveling direction of the communication area in the downlink information from the communication unit of the optical beacon. The vehicle traveling direction length from the beginning of the uplink region to the end of the downlink region is set within the distance error range of the predetermined position, and is included in the downlink information received by the in-vehicle device. This is performed by recognizing the distance to the predetermined position based on the distance information.

  According to the road-to-vehicle communication system having such a configuration, the vehicle-mounted device used in the road-to-vehicle communication system, and the distance recognition method performed using the road-to-vehicle communication system, the downlink region from the start of the uplink region Since the vehicle traveling direction length to the end of the vehicle is set within the range of the distance error of the predetermined position, the on-vehicle device can receive this distance information at any position in the communication area. Based on the distance information, the distance to the predetermined position can be accurately recognized within the range of the distance error.

  According to the present invention, on the vehicle side, the distance to a predetermined position ahead can be accurately recognized based on the received distance information. Thus, the vehicle can be stopped accurately according to the predetermined position, or a warning for prompting the driver to stop or decelerate can be notified by voice or display.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an outline of a road-to-vehicle communication system using an optical beacon according to the present invention and an in-vehicle device mounted on a vehicle. FIG. 2 is a diagram for explaining driving support control for a vehicle using the road-to-vehicle communication system. FIG. 3 is a diagram showing a schematic configuration of a vehicle equipped with an optical beacon and an in-vehicle device.

  In FIG. 1, a central device 30 is provided on the traffic control station side, and is connected to each of a large number of optical beacons (optical vehicle detectors) 2 provided on a road via a communication line such as a telephone line. . Various information is transmitted and received between the central apparatus 30 and the terminal communication unit 2d (see FIG. 3) of each optical beacon 2 via a communication line. Specifically, referring to FIG. 2, the central device 30 is configured to communicate with each of the optical beacons 2 provided on the road R, and a road-to-vehicle communication area A (hereinafter referred to as a communication area A). Information on the distance to a predetermined position P on the road R located in front of the vehicle traveling direction (hereinafter referred to as distance information) is transmitted. This distance information is registered and stored in each optical beacon 2. The distance information may be information that is fixedly stored in the optical beacon 2 when the optical beacon 2 is installed, for example, in addition to being transmitted from the central device 30 and received by the optical beacon 2.

  In FIG. 3, the optical beacon 2 communicates with a communication unit 2a that communicates with the vehicle-mounted device 1 mounted on the vehicle C, a control unit 2b that is connected to the communication unit 2a, and a central device 30 for communication. Terminal communication unit 2d. In FIG. 2, the communication unit 2 a is attached to an upper portion of a column 6 erected on the road side, and is set so that a predetermined range with respect to the road R is a communication area A. The communication unit 2a transmits the distance information to the communication area A. The control unit 2b has a function of controlling the communication unit 2a and has a storage unit 2c that stores the distance information.

  The distance information will be described. In FIG. 2, when the predetermined position P in front of the vehicle traveling direction is, for example, a stop line P provided on the road R in front of an intersection where the traffic signal 10 is located, this distance information is obtained from the stop line P. Information about the actual distance to the communication area A by the beacon 2 is used. More specifically, the distance information can be information on the distance L between the position of the stop line P (arrow Z) and the end of the communication area A (arrow Xc). The communication area A is a range of a state where the optical beacon 2 and the vehicle-mounted device 1 can communicate.

The communication area A set in the communication unit 2a of the optical beacon 2 will be described. In FIG. 4, the communication area A includes a downlink communicable area (hereinafter referred to as a downlink area) and an uplink communicable area (hereinafter referred to as an uplink area). The uplink area is an area where the optical beacon 2 can receive the uplink information from the vehicle C side (vehicle equipment 1), and the downlink area is the area where the optical beacon 2 receives the downlink information from the vehicle C side (vehicle equipment 1). It is an area where the vehicle C side can receive the downlink information. In FIG. 4, the uplink region overlaps with the front portion (upstream portion) of the downlink region in the vehicle traveling direction, and the downlink region coincides with the communication region A.
Further, as shown by the solid line in FIG. 4, the start end of the uplink region in the vehicle traveling direction is matched with the start end of the downlink region in the vehicle traveling direction. The starting end of the link area may be further upstream (right side) in the vehicle traveling direction. In the following description, the case where the start edge of the uplink area matches the start edge of the downlink area will be described.

  In FIG. 3, the vehicle-mounted device 1 is mounted on the vehicle C, and enables bidirectional communication with the communication unit 2 a of the optical beacon 2 using near infrared rays. The in-vehicle device 1 includes a communication unit 11 as an antenna, and a control unit 12 that processes various information for signals received by the communication unit 11 and signals emitted from the communication unit 11. Then, the vehicle C travels toward the communication area A, the communication unit 11 receives a signal from the optical beacon 2 in a state where the in-vehicle device 1 is in the downlink area, and the control unit 12 uses this signal, For example, in order to stop the vehicle C on which the vehicle-mounted device 1 is mounted according to the stop line P, a distance from the current travel position to the stop line P ahead in the vehicle traveling direction is obtained.

  And in this invention, in FIG. 4, the optical beacon 2 has a vehicle traveling direction length a from the starting end Xa of the uplink region to the terminal end Xc of the downlink region, that is, the length a of the communication region A in the traveling direction of the vehicle. The length a of the communication region A in the vehicle traveling direction is set within the range of “distance error of the stop line P”. The “distance error of the stop line P” means a distance error that can be considered that the vehicle C is substantially at the position of the stop line P in relation to the length of the vehicle C, and specifically, Is the normal stop distance e at which the driver feels that the vehicle C has stopped comfortably before the stop line P. Therefore, in this case, the length a of the communication area A in the vehicle traveling direction is set to be equal to or less than the normal stop distance e (a ≦ e).

  And the distance recognition method which calculates | requires the distance to the stop line P ahead of the vehicle advancing direction performed by the road-to-vehicle communication system provided with this optical beacon 2 and the vehicle equipment 1 is the downlink information from the communication part 2a of the optical beacon 2. Includes the “distance information” to the stop line P located in front of the vehicle travel direction in the communication region A, and the vehicle travel direction length a from the start end Xa of the uplink region to the end point Xc of the downlink region, This can be done by setting the distance to the normal stop distance e or less and recognizing the distance to the stop line P based on the “distance information” included in the downlink information received by the in-vehicle device 1. The normal stop distance e can be set to about 2.5 m as described later.

  Also, in the present invention, in FIG. 4, the length a2 in the vehicle traveling direction of the region from the uplink region end Xb to the downlink region end Xc (hereinafter referred to as the second region A2) is the transmission of the downlink information. The optical beacon 2 is set so as to be equal to or greater than the distance obtained by the product of the period and the maximum corresponding speed of the vehicle C. In this case, the length a2 of the second region A2 in the vehicle traveling direction is set to 1.2 times or less of the distance obtained by the product of the transmission period of the downlink information and the maximum corresponding speed of the vehicle C. be able to.

The maximum supported speed is a maximum speed that guarantees that the in-vehicle device 1 receives the distance information, and is set in advance in a system including the optical beacon 2 and the in-vehicle device 2. Is speed. That is, there is a possibility that the distance information about the distance to the stop line P cannot be reliably given to the in-vehicle device 1 of the vehicle C traveling exceeding the maximum corresponding speed.
The downlink information from the optical beacon 2 is composed of one or a plurality of types of information, and each information is composed of one or a plurality of frames. Then, the one or a plurality of frames are sequentially and repeatedly transmitted at a predetermined transmission cycle. Here, the downlink information transmission cycle refers to a cycle from the transmission of the first frame of the one or more frames to the transmission of the first frame again.

  The length a2 in the vehicle traveling direction of the second area A2 set in the optical beacon 2 as described above will be specifically described. The case where the maximum corresponding speed is set to 90 km / h will be described. Moreover, in the optical beacon 2 currently used in the traffic control system (road-to-vehicle communication system), the downlink is composed of 1 to 80 frames, and this downlink is transmitted repeatedly in the downlink transmission cycle. Has been. The “distance information” and “lane notification information” to be described later are included in this downlink frame. Therefore, the transmission period of the downlink information from the optical beacon 2 is described as 84 msec corresponding to the case of 80 frames having the maximum number of frames.

In this case, the length a2 of the second region A2 in the vehicle traveling direction is set to 2.1 m or more which is a product of the transmission period of the downlink information: 84 msec and the maximum corresponding speed of the vehicle C: 90 km / h. Is preferred. And it is preferable to set the said length a2 to 2.52 m or less which is 1.2 times this 2.1 m. According to this, the vehicle-mounted device 1 of the vehicle C traveling at the maximum corresponding speed (90 km / h) can receive the downlink for at least one cycle (80 frames) in the second region A2. That is, the in-vehicle device 1 can receive the entire downlink frame at least once, and the length a2 of the second region A2 in the vehicle traveling direction is increased by 20% (1.2 times), thereby reliably downlinking. Can be received.
According to this, the optical beacon 2 receives uplink information from the vehicle-mounted device 1 for the first time at a position near the end Xb of the uplink region, and then the optical beacon 2 immediately transmits downlink information. However, the optical beacon 2 can transmit the “distance information” to the vehicle-mounted device 1 by setting the length a2 of the second region A2 to 2.1 m or more as described above. Can receive.

  Further, according to the present invention, the length a1 of the vehicle traveling direction of the region from the start Xa of the uplink region to the end Xb of the uplink region (hereinafter referred to as the first region A1) is determined by the uplink information transmission period and the vehicle The optical beacon 2 is set to be equal to or greater than the distance obtained by the product with the maximum corresponding speed. In this case, the length a1 of the first region A1 in the vehicle traveling direction is set to 1.2 times or less of the distance value obtained by the product of the uplink transmission cycle and the maximum corresponding speed of the vehicle C. Can do.

More specifically, when the maximum corresponding speed is set to 90 km / h and the uplink transmission cycle in the in-vehicle device 1 is set to 40 msec, the length a1 of the first region A1 in the vehicle traveling direction is the uplink. The transmission cycle is preferably set to 1.0 m or more which is the product of 40 msec and the maximum corresponding speed of the vehicle C: 90 km / h. And it is preferable that the said length a1 shall be 1.2 m or less which is 1.2 times this 1.0 m.
According to this, the optical beacon 2 can receive uplink information for at least one cycle from the in-vehicle device 1 of the vehicle C that is in the first region A1 and travels at the maximum corresponding speed (90 km / h). Further, by increasing the length a1 by 20% (1.2 times), it is possible to reliably receive an uplink. Thereby, the optical beacon 2 can surely receive the signal by the uplink transmission from the in-vehicle device 1, and based on this, the optical beacon 2 can transmit the downlink information to the in-vehicle device 1 and transmit the distance information to the in-vehicle device 1.

Bidirectional communication performed between the optical beacon 2 and the vehicle-mounted device 1 in the communication area A will be described with reference to FIG.
The optical beacon 2 continues to transmit “information including lane notification information” as first information to the downlink region of the communication region A of the road R at a predetermined transmission cycle (F1 in FIG. 5). Note that the vehicle ID is not stored in the lane notification information. When the vehicle C equipped with the vehicle-mounted device 1 enters the communication area A and the vehicle-mounted device 1 receives the “information including the lane notification information (no vehicle ID)”, the vehicle-mounted device 1 is in the communication area A. Can be recognized. When this recognition is performed, the vehicle-mounted device 1 starts uplink transmission (F2 in FIG. 5), and transmits “uplink information” to the optical beacon 2 at a predetermined transmission cycle (F3 in FIG. 5). This transmission by the in-vehicle device 1 is performed in the uplink region (see FIG. 4). Further, the vehicle ID of the vehicle itself is stored in the “uplink information”. Note that “uplink information” continues to be transmitted until the subsequent recognition by the in-vehicle device 1 that “the optical beacon 2 has performed downlink switching” is performed in the in-vehicle device 1.

  When the optical beacon 2 receives the “uplink information” from the in-vehicle device 1 (F4 in FIG. 5), “lane notification information (with vehicle ID)” for the in-vehicle device 1 as the second information. "Information including" is transmitted (F6 in FIG. 5). That is, based on the vehicle ID stored in the “uplink information” received by the optical beacon 2 first, the optical beacon 2 (control unit 2b) includes the “lane notification information as second information. The vehicle ID is stored in “information” (F5 in FIG. 5).

  The “information including lane notification information (with vehicle ID)” further includes the “distance information”. That is, when the optical beacon 2 receives “uplink information” including the vehicle ID from the vehicle-mounted device 1 (F4 in FIG. 5), the vehicle ID corresponding to the vehicle-mounted device 1 is included for the communication area A. “Information including lane notification information and distance information” is transmitted (F6 in FIG. 5), and the in-vehicle device 1 can receive this information in the downlink region (F7 in FIG. 5).

  Then, when the vehicle-mounted device 1 receives the “information including lane notification information and distance information” (F7 in FIG. 5), the control unit 2b of the vehicle-mounted device 1 indicates that “the optical beacon 2 performs downlink switching. The distance L (see FIG. 2) from the current travel position of the vehicle C (onboard device 1) to the front stop line P at this time is obtained as the distance based on the received “distance information” (see FIG. 2). (F8 in FIG. 5). Further, when the in-vehicle device 1 recognizes that “the optical beacon 2 has switched the downlink”, it stops the transmission of the “uplink information”.

  Further, as a modification of the bidirectional communication performed between the optical beacon 2 and the vehicle-mounted device 1 in the communication area A, even if the optical beacon 2 does not receive the uplink from the vehicle-mounted device 1 (receives the uplink). Regardless of whether or not), the “distance information” may be transmitted in the downlink region of the communication region A, and the in-vehicle device 1 may receive this in the downlink region.

Next, the case where the optical beacon 2 is set so that the length a in the vehicle traveling direction of the communication area A is equal to or less than the normal stop distance e (a ≦ e) will be specifically described.
A case where the normal stop distance e is set to 2.5 m will be described. In this case, in FIG. 2 and FIG. 3, the length a of the communication area A in the vehicle traveling direction is set to 2.5 m, which is the same as this, and the position of the stop line P (arrow Z) by the “distance information” The distance L from the end Xc of the communication area A will be described as 50 m.
First, the in-vehicle device 1 receives downlink information in a state where the in-vehicle device 1 exists at the position of the start end Xa of the uplink region (see FIG. 4), and then the optical beacon 2 receives the uplink information of the in-vehicle device 1 and runs. The vehicle-mounted device 1 of the vehicle C receives downlink information including “distance information” at a position (position indicated by an arrow X1) advanced by a travel distance G1 (see, for example, 1 m) from the position of the starting end Xa. A case where “distance information” is recognized will be described.

  In this case, the vehicle-mounted device 1 recognizes that there is a stop line P at a position (arrow Z1) ahead by a distance L1 (L1 = L = 50 m) according to the “distance information” from the point where the “distance information” is recognized (arrow X1). To do. That is, since the “distance information” is information on the distance L between the position of the stop line P (arrow Z) and the position of the terminal Xc of the communication area A, the vehicle-mounted device 1 is configured to detect the actual stop line P. It will be recognized that the position (arrow Z1) in front of the position (arrow Z) by “a certain distance f” is the position of the stop line P. However, even in this case, the error “a certain distance f” is obtained by subtracting the traveling distance G1 (1 m) from the length a (2.5 m) of the communication area A in the vehicle traveling direction ( 1.5m). That is, the vehicle-mounted device 1 can recognize that the position 1.5 m before the actual stop line P is the position of the stop line P, and can stop the vehicle C at the recognized position. As a result, the driver can feel that the vehicle has stopped without a sense of incongruity before the stop line P.

Next, the optical beacon 2 has received the uplink information from the in-vehicle device 1 at the position where the in-vehicle device 1 is present in the uplink region (see FIG. 4). Explanation is given for a case where the vehicle-mounted device 1 receives the downlink information from the optical beacon 2 and recognizes the “distance information” at a position that has traveled a traveling distance G2 of 2.5 m from the start end Xa of the uplink region (start end of the downlink region). To do.
In this case, the vehicle-mounted device 1 recognizes that there is a stop line P at a position (arrow Z) ahead by a distance L2 (L2 = L = 50 m) according to the “distance information” from the point where the “distance information” is recognized (arrow Xc). can do. In this case, the distance recognition error is zero.

  As described above, since the length a of the communication area A in the vehicle traveling direction is equal to or less than the normal stop distance e, the in-vehicle device 1 receives “distance information” at any position in the traveling direction in the communication area A. Even if it recognizes, the value of the normal stop distance e can be made into the maximum error, and the vehicle equipment 1 can obtain | require the distance to the stop line P based on "distance information". In this way, by limiting the length a of the communication area A in the vehicle traveling direction of the optical beacon 2, the communication area A is narrowed down, and the range in which the in-vehicle device 1 can receive information is limited. Thereby, it is possible to cause the vehicle C to perform control for stopping the vehicle C on which the vehicle-mounted device 1 is mounted according to the stop line P within the range of the normal stop distance e.

Moreover, the other form about recognition of the distance to the stop line P by the vehicle equipment 1 is demonstrated.
The case where the value of the normal stop distance e is set to the vehicle length of one ordinary passenger car (for example, 4.2 m to 4.8 m) will be described. Here, the normal stop distance e is assumed to be 4.2 m. In this case, the optical beacon 2 side is set so that the length a of the communication area A in the vehicle traveling direction is equal to or less than the normal stop distance e. Even in this case, as in the case described above, the value of the normal stop distance e (the vehicle of a normal passenger car) Length) is the maximum error, and the distance to the stop line P can be obtained.

  Further, in the embodiment in which the length a of the communication area A in the vehicle traveling direction is limited, the in-vehicle device 1 has the stop line P at a position before the stop line P that actually exists. The distance can be obtained so as to be recognized. That is, when the normal stop distance e is set to 2.5 m, the vehicle-mounted device 1 recognizes the position in front of the actual stop line P and the error within the range of 2.5 m as the position of the stop line P. it can. Thus, the vehicle C can be stopped within a range of 2.5 m before the actual stop line P by the action of the travel control means 9 (described later) mounted on the vehicle C. Further, when the normal stop distance e is the vehicle length of a normal passenger car, the vehicle C can be stopped at a position before the actual stop line P and within the vehicle length of one vehicle. In particular, when the normal stop distance e is set to 2.5 m, the driver of the own vehicle and the drivers of other surrounding vehicles can be made to think that the vehicle has stopped according to the stop line P at a distance that does not feel strange. That is, from such a viewpoint, it is preferable that the length a in the vehicle traveling direction of the communication area A by the optical beacon 2 is 2.5 m or less.

In the case of a general road, the communication area A in the optical beacon road-to-vehicle communication system using the optical beacon 2 and the in-vehicle device 1 is, for example, an uplink area of 1.6 m and a downlink area of 3. 7 m can be set. However, since the optical beacon of the road-to-vehicle communication system currently used is installed for the purpose of providing traffic information such as VICS to the in-vehicle device 1, it is important to ensure the amount of information and to ensure the communication. The actual range of the communication area A is set to be about twice as large as these values (1.6 m, 3.7 m).
Therefore, in the present invention, as described above, the range of the communication area A (the length a in the vehicle traveling direction) is limited and limited, thereby improving the accuracy of recognition of the distance of the predetermined position (stop line) P ahead. By setting the length of each area of the communication area A in the vehicle traveling direction to a predetermined value, the communication performance can be maintained.

  According to each embodiment by the optical beacon 2 and the vehicle-mounted device 1 configured as described above, the optical beacon 2a receives an uplink from the vehicle-mounted device 1 mounted on the vehicle C that has entered the communication area A. “Distance information” about the distance from the communication area A to the stop line P ahead in the vehicle traveling direction can be transmitted to the in-vehicle device 1. This “distance information” is received by the vehicle-mounted device 1 in the communication area A, and the vehicle-mounted device 1 can recognize the distance to the stop line P.

  And the control part 12 of the vehicle equipment 1 which recognized the distance to the stop line P is based on this distance, for example, in order to stop the vehicle C according to the stop line P, the traveling control means 9 with which the vehicle C is provided. To perform driving support control. The traveling control means 9 can control the traveling speed to be a predetermined speed based on the speed information of the vehicle C from the speed detecting means (acceleration sensor) 8 mounted on the vehicle C. That is, the traveling control means 9 can instruct the driving means (engine) 21 and the braking means (brake) 22 of the vehicle C to perform acceleration and deceleration operations. The traveling control means 9 is composed of a microcomputer and can be an ECU. Further, the speed detecting means 8 can be configured to be provided in the in-vehicle device 1 (FIG. 3), or can be configured to be provided in the vehicle C as a separate body from the in-vehicle device 1 (not shown).

  As shown in FIG. 2, the travel control means 9 is based on the distance L to the stop line P obtained by the control unit 12 of the in-vehicle device 1 and the travel speed detected by the speed detection means 8. The traveling is controlled so that the speed of the vehicle C becomes zero when the vehicle travels only by the time. That is, a control for automatically stopping the vehicle C at the front stop line P is performed. This travel control will be described in detail. Based on the distance L to the stop line P obtained by the control unit 12 of the in-vehicle device 1, the control unit 12, the speed detection unit 8, and the travel control unit 9 are mutually connected. As the vehicle C travels, the control unit 12 obtains the remaining distance to the point of the distance L as needed, and the travel control means 9 gradually adjusts the vehicle in the section to the point of the distance L. C is decelerated, and the speed of the vehicle C is set to zero when the vehicle travels a distance L. Thereby, the vehicle C can be automatically stopped on the stop line P.

Further, the present invention is not limited to the illustrated form, and may be other forms within the scope of the present invention. The operation of the vehicle C side that recognizes the distance to the predetermined position ahead is performed with respect to the vehicle C. Although the mode of braking and stopping has been described, other than this, a warning that prompts the driver who is driving the vehicle C to stop or decelerate may be output by voice or displayed on a monitor mounted in the vehicle. .
In the embodiment in which the vehicle C is braked and stopped, the predetermined position is described as the position of the stop line P. However, the predetermined position can be a position where a traffic light is present, a position of a vehicle detector, or the like. Further, regarding the distance information, in the above-described embodiment, the reference position on the communication area A side for the distance information has been described as the end Xc of the communication area A, but other distances may be used. The distance from the predetermined position P to the start end of the communication area A or the distance from the predetermined position P to the end position of the uplink area can be used. Furthermore, the reference position on the communication area A side may be the position of the communication unit 2a of the optical beacon 2, that is, the position directly below the communication unit 2a, and the distance from the position immediately below to the predetermined position P may be the distance based on the distance information.

  In addition, the distance information transmitted from the optical beacon 2 is not in the form of a direct information about the distance to the predetermined position (stop line) P as in the embodiment, but from the communication area A to the predetermined position P. It can be in other formats in which the distance to is stored. That is, as the distance information, a plurality of nodes are specified from the communication area A to the predetermined position P, the distance from the communication area A to the nearest node, the distance between the nodes, and the nearest position P. Each distance from the node to the predetermined position P can be stored.

It is a figure which shows the outline of the road-vehicle communication system by the optical beacon of this invention and the vehicle equipment mounted in a vehicle. It is a figure explaining the driving assistance control of the vehicle performed using a road-vehicle communication system. It is a figure which shows schematic structure of the vehicle carrying an optical beacon and vehicle equipment. It is a figure explaining the communication area | region set in the optical beacon. It is a figure explaining the bidirectional | two-way communication performed between an optical beacon and vehicle equipment in a communication area.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Onboard equipment 2 Optical beacon 2a Communication part 2b Control part 2c Memory | storage part A Communication area C Vehicle P Stop line (predetermined position)
R road

Claims (10)

In an optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted,
The downlink information from the communication unit includes distance information to a predetermined position located in front of the communication area in the vehicle traveling direction,
An optical beacon, wherein a length in a vehicle traveling direction from a start end of the uplink region to a terminal end of the downlink region is set within a range error range of the predetermined position. In an optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted,
The downlink information from the communication unit includes distance information to a predetermined position located in front of the communication area in the vehicle traveling direction,
The vehicle traveling direction length from the end of the uplink region to the end of the downlink region is set to be greater than or equal to the distance obtained by the product of the transmission period of the downlink information and the maximum corresponding speed of the vehicle. Characteristic light beacon.   The vehicle traveling direction length from the end of the uplink region to the end of the downlink region is set to 1.2 times or less of the distance obtained by the product of the transmission period of the downlink information and the maximum corresponding speed of the vehicle. The optical beacon according to claim 2. In an optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted,
The downlink information from the communication unit includes distance information to a predetermined position located in front of the communication area in the vehicle traveling direction,
The vehicle traveling direction length from the start end of the uplink region to the end of the downlink region is set within the range error distance of the predetermined position, and from the end of the uplink region to the downlink region An optical beacon characterized in that the vehicle traveling direction length to the end is set to be equal to or greater than the distance obtained by the product of the downlink information transmission cycle and the maximum corresponding speed of the vehicle. In an optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted,
The downlink information from the communication unit includes distance information to a predetermined position located in front of the communication area in the vehicle traveling direction,
The vehicle traveling direction length from the start end of the uplink region to the end of the uplink region is set to be greater than or equal to the distance obtained by the product of the uplink information transmission cycle and the maximum corresponding speed of the vehicle. Characteristic light beacon.   The length of the vehicle traveling direction from the start of the uplink region to the end of the uplink region is set to 1.2 times or less of the distance obtained by the product of the uplink information transmission cycle and the maximum corresponding speed of the vehicle. The optical beacon according to claim 5. In an optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted,
The downlink information from the communication unit includes distance information to a predetermined position located in front of the communication area in the vehicle traveling direction,
The vehicle traveling direction length from the start of the uplink region to the end of the downlink region is set within the distance error range of the predetermined position, and the length of the uplink region from the start of the uplink region An optical beacon characterized in that a vehicle traveling direction length to the end is set to be equal to or greater than a distance obtained by a product of a transmission cycle of the uplink information and a maximum corresponding speed of the vehicle. An optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted, and the uplink information and downlink information in the communication area In a vehicle-to-vehicle communication system equipped with an in-vehicle device that transmits and receives
The downlink information from the communication unit of the optical beacon includes distance information to a predetermined position located forward in the vehicle traveling direction of the communication area, from the start end of the uplink area to the end of the downlink area The road-to-vehicle communication system is characterized in that the vehicle traveling direction length is set within a range of a distance error of the predetermined position.   An in-vehicle device used in the road-to-vehicle communication system according to claim 8. An optical beacon including a communication unit having a communication area composed of an uplink area where uplink information can be received and a downlink area where downlink information can be transmitted, and the uplink information and downlink information in the communication area A distance recognition method performed using a road-to-vehicle communication system including
The downlink information from the communication unit of the optical beacon includes distance information to a predetermined position located forward in the vehicle traveling direction of the communication area, and the vehicle from the start end of the uplink area to the end of the downlink area The traveling direction length is set within the distance error range of the predetermined position,
A distance recognition method performed using a road-to-vehicle communication system, wherein a distance to the predetermined position is recognized based on the distance information included in the downlink information received by the in-vehicle device.

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