JP4802955B2 - Communication device, position detection device, and road-vehicle communication system - Google Patents

Description

  The present invention relates to a communication device, a position detection device, and a road-to-vehicle communication system, and more particularly, to a communication device, a position detection device, and a road-to-vehicle communication system that communicate using beacons.

  In a road-to-vehicle communication system, a device installed on the road side communicates with a communication device mounted on a vehicle to provide traffic information, current position information, and the like to the vehicle. In VICS (Vehicle Information and Communication System), which is a type of road-to-vehicle communication system, roadside devices transmit information to vehicles using optical beacons, radio wave beacons, FM multiplex broadcasts, etc., but optical beacons further transfer from vehicles to roadside devices. Uplink to transmit information is possible. In the uplink, for example, the vehicle ID number is transmitted to the roadside device, and the roadside device calculates the passing time of a predetermined section based on the vehicle ID and provides it to each vehicle.

  By the way, in the infrastructure cooperation system, roads acquired from VICS etc., such as using the road-to-vehicle communication system to a high degree and automatically applying braking when the driver does not take an evasive operation in front of the intersection at the red light. Intervention control according to specific traffic regulation information is being studied. In order to realize such an advanced infrastructure cooperation system, it is conceivable to effectively use vehicle information transmitted by the uplink. On the other hand, the communication range of the optical beacon is several meters before the roadside device. Therefore, it is necessary to transmit a lot of information while traveling this short distance.

  The uplink period may be shortened as one method for transmitting a lot of information. However, in the uplink using an optical beacon, the communication device repeatedly turns on and off the light emitting diode (LED) and transmits information to the roadside device. Therefore, if the light emission period of the LED is shortened, there is an inconvenience that the amount of light is reduced due to heat generation of the LED, and the life is shortened due to image sticking.

In order to reduce the burden on the LED, an optical beacon transmission device that controls the uplink transmission procedure in accordance with the speed of entry into the communicable range has been proposed (see, for example, Patent Document 1). The optical beacon transmission device described in Patent Document 1 shortens the uplink transmission interval when the intrusion speed is fast, and lengthens the uplink transmission interval when the intrusion speed is slow. To reduce the burden.
Japanese Patent Laid-Open No. 10-332803

  However, the optical beacon device described in Patent Document 1 has a problem in that, when the intrusion speed is high, the uplink transmission interval is shortened, and thus the LED is still burdened.

  An object of this invention is to provide the communication apparatus and road-to-vehicle communication system which perform an uplink, without overloading the communication apparatus of an optical beacon in view of the said subject. Moreover, it aims at providing the position detection apparatus which detects the position of a vehicle from the information acquired from the infrastructure cooperation system by uplink.

In view of the above problems, the present invention is specified by an uplink success position specifying means for specifying an uplink failure position and a success position and an uplink success position specifying means in a vehicle communication device that communicates with a roadside beacon head. And an uplink position storage means for storing at least one of the failed position and the successful position , and an uplink position control means for starting an uplink from the successful position .

  According to the present invention, since it is not necessary to always uplink with a short cycle, the durability of the optical element of the optical beacon does not deteriorate.

The present invention also provides an uplink means for uplink to a roadside beacon head, an uplink success position specifying means for specifying an uplink failure position and a success position, and a failure position specified by the uplink success position specifying means. Or an uplink position storage means for storing at least one of the successful positions, an uplink position control means for starting an uplink from the successful position, and a point at which a downlink transmitted from the beacon head after the uplink is received. There is provided a position detection device characterized by comprising position evaluation means for detecting the position of a moving body.

  According to the present invention, since the position is evaluated at a point where the uplink succeeds reliably, the position of the host vehicle can be detected with high accuracy based on information obtained by road-to-vehicle communication.

  It is possible to provide a communication device and a road-to-vehicle communication system that perform uplink without imposing an excessive burden on the optical beacon communication device.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The road-to-vehicle communication system of the present embodiment makes it possible to use the uplink position in communication using an optical beacon as a medium as vehicle position information in the infrastructure cooperation system.

  In the infrastructure coordination system, the vehicle speed capable of relieving about 90% of accidents in consideration of the accident reduction effect is set to a relatively high vehicle speed (for example, 90 km / h). Therefore, it is necessary to evaluate the uplink position so that the position of the error falls within a predetermined error. Note that rating refers to determining the position of a vehicle based on position information such as features acquired by a road-to-vehicle communication system.

  FIG. 1 is a diagram illustrating an example of communication between a roadside device and a vehicle in communication using an optical beacon as a medium. In FIG. 1, an arrow in the direction from the roadside device to the vehicle 1 indicates downlink communication, and an arrow in the direction from the vehicle 1 to the roadside device indicates uplink communication. A space seen from the roadside optical beacon head 2 of the roadside device at a predetermined depression angle with respect to the road is a space where the communication device 3 and the roadside optical beacon head 2 can communicate. In FIG. 1, the side close to the vehicle 1 that travels (area indicated as DW) is an area where downlink is possible, and the side close to the roadside optical beacon head 2 (area indicated as UP & DW) is downlink and uplink. (Hereinafter, both are simply referred to as an optical beacon region, and the starting point is referred to as an optical beacon region start position).

  The roadside optical beacon head 2 always transmits traffic information such as traffic jam information to the optical beacon area, and the communication device 3 automatically receives the traffic information when entering the optical beacon area. And when it is detected that the communication device 3 has entered the optical beacon area by receiving traffic information through the downlink, when transmitting a vehicle ID to the roadside optical beacon head 2 or requesting additional information, The communication device 3 uplinks to the roadside optical beacon head 2.

  Here, in the infrastructure cooperation system, it is assumed that information such as the color of the signal ahead (hereinafter referred to as a signal state) is transmitted from the roadside optical beacon head 2, and the vehicle 1 has a red signal. Nevertheless, when the vehicle 1 is likely to enter an intersection without decelerating, it is expected that the in-vehicle device of the vehicle 1 automatically intervenes in the driver and stops automatically.

  Therefore, in this embodiment, the position of the vehicle 1 is determined based on the feature such as the roadside device by determining the successful uplink position as the position of the vehicle 1 immediately after receiving the downlink from the roadside optical beacon head 2. Is accurately evaluated.

  For example, in FIG. 1, uplink arrows a to c are described, but if succeeding in a, the position of the uplink a becomes the position of the vehicle 1. In other words, the vehicle 1 can be automatically stopped before the stop line, if necessary, assuming that a traffic light is present XX meters ahead of the successful uplink position.

  By the way, all the uplinks performed by the communication device 3 are not necessarily successful, and may fail depending on the transmittance of the windshield (the angle of the windshield with respect to the depression angle of the roadside optical beacon head 2), the sensitivity of the receiving device, and the like. For this reason, the communication apparatus 3 is set to repeat the uplink at a predetermined cycle. For example, when the uplink a in FIG. 1 fails and the uplink b is established, the position of the uplink b is set. Is the position of the vehicle 1, and when the uplink b fails and the uplink c is established, the position of the uplink c is set as the position of the vehicle 1.

  However, the position information of the intersection and stop line transmitted in the downlink (for example, XX m ahead from the roadside optical beacon head 2, position coordinates, etc.) is fixed information, whereas the position where the uplink succeeds. If is undefined, the error in the position of the vehicle 1 to be rated will increase.

  Here, even if the uplink is scheduled to fail, if the uplink cycle is short, the uplink is successively performed, so that the uplink succeeds early, and the error of the estimated position can be reduced. The uplink period and error magnitude will be described.

  FIG. 2A shows an example of conventional communication with a long uplink cycle, and FIG. 2B shows an example of communication when the uplink cycle is short. For example, when the vehicle 1 travels at 90 km / h when the conventional cycle shown in FIG. 2A is 60 milliseconds, the vehicle travels 1.5 m during one uplink. An error of 1.5 m also occurs in the position of the vehicle 1 to be rated.

  Assuming that the accuracy of the position required for intervention control is within an error of about 2.5m, for example, if the position evaluated by the uplink includes an error of 1.5m, other errors (for example, vehicle speed, etc.) May not meet the accuracy required for interventional control.

  Therefore, it is conceivable to shorten the uplink period (for example, about half = 30 milliseconds). As shown in FIG. 2 (b), when the uplink period is k times, the estimated position error can be expected to be 1 / k. However, as described above, if the period is shortened, it is expected that the temperature of the optical element of the optical beacon will rise and the life of the communication device 3 will be shortened, which is not preferable. That is, it is difficult to improve the accuracy of the position of the vehicle to be evaluated simply by shortening the uplink cycle.

  Incidentally, the cause of the communication device 3 failing in the uplink, such as the above-described transmittance of the windshield, is unique to each vehicle. On the other hand, the optical beacon area is almost constant regardless of the road side optical beacon head 2 of any road. Therefore, the position where the communication device 3 fails in the uplink in the optical beacon region can be specified for each vehicle.

  As described above, in the present embodiment, the success or failure of the uplink in the optical beacon area is recorded in advance, and the uplink is efficiently performed at the position where the uplink is established, so that the deterioration of the optical element is reduced and the position of the accurate position is improved. Allows rating.

  FIG. 3A shows an example of the success or failure of the recorded uplink. In FIG. 3A, the uplinks a to d made at a predetermined cycle alternately repeat success and failure. When such a record is obtained, the communication device 3 evaluates the position by uplinking at the positions of the uplinks b and d without performing the uplink at the positions of the failed a and c. In FIG. 3B, uplinks that are not actually performed are indicated by dotted lines.

  As shown in FIG. 3B, since the number of uplinks is small even if it enters the optical beacon area, there is no possibility that the lifetime of the optical element will be shortened. The position can be accurately evaluated even if the period is long.

  The configuration of the road-vehicle communication system will be described. FIG. 4 shows an example of a schematic configuration diagram of a road-vehicle communication system using an optical beacon as a medium. In the road-to-vehicle communication system for optical beacons, data is transmitted and received using a far-infrared ray from a road-side optical beacon head 2 provided on a road using a beacon as a medium.

  When the vehicle 1 enters the optical beacon area, a downlink for transmitting the entry from the road side optical beacon head 2 to the optical beacon area is transmitted to the communication device 3.

  The communication device 3 receives the downlink with the photodiode 16 and amplifies it with low noise by the amplifier 15. The amplified signal is converted into a square wave by the comparator 14 and input to the control unit 13. The control unit 13 is a CPU that executes a program, a RAM that serves as a work area for program execution or temporarily stores data, an NV (nonvolatile) -RAM that retains data even when the ignition is turned off, and inputs and outputs data These microcomputers are connected to each other by an input / output interface and a ROM for storing programs.

  When the CPU executes the program, the uplink success position specifying means 13a and the uplink position control means 13b are realized. The uplink position storage means 13c corresponds to, for example, NV-RAM, and stores the uplink failure position and success position specified by the uplink success position specifying means 13a.

  The control unit 13 checks whether the downlink converted into the square wave has a predetermined frame pattern and whether the error check is consistent, and if it is determined that it is a downlink, the optical beacon region Recognize that it is in the area.

  The control unit 13 that has received the downlink outputs uplink data such as a vehicle ID to the drive circuit 12. The drive circuit 12 lights the optical element 11 according to the uplink data. Thereby, an optical beacon reaches the roadside beacon head 2 from the communication device 3 and is received by the roadside beacon head 2 in the same procedure.

  When the uplink succeeds and the roadside optical beacon head 2 receives the vehicle ID or the like, the roadside optical beacon head 2 transmits the traffic information based on the situation of each vehicle to the vehicle 1 again through the downlink together with the vehicle ID. The traffic information transmitted again includes, for example, the above-described intersection and stop line position information, traffic signal status, traffic regulation, travel time between links, and the like.

  The communication device 3 receives the downlink including the vehicle ID, and confirms that the uplink is established when the vehicle ID is included. The control unit 13 is connected to an in-vehicle LAN such as a CAN (Controller Area Network), and sends traffic information and the like transmitted together with the vehicle ID to the navigation system 18 and the brake ECU 19.

  The navigation system 18 detects the position of the vehicle 1 by GPS (Global Positioning System) or autonomous navigation. Then, the position rating means 18a corrects the position based on the traffic information acquired on the downlink, assuming that the host vehicle exists at a predetermined distance from the intersection (stop line). Further, the travel distance from the uplink position is measured by the vehicle speed sensor 17, and if necessary, the brake ECU 19 is requested to automatically decelerate and stop.

  The traffic information is edited and distributed by the roadside device 4. The roadside device 4 is configured as a computer and is connected to a traffic signal in the traveling direction of the vehicle 1 and a center for collecting traffic jam information, and forms traffic information such as traffic signal status and traffic jam information in a predetermined frame pattern, Send to the optical beacon head 2.

  In the above configuration, the uplink success position specifying unit 13a specifies the uplink failure position and the success position. As described above, the uplink success position specifying unit 13a repeats the uplink with a cycle shorter than the conventional one (for example, half of the conventional cycle B, hereinafter referred to as the cycle A). For example, every time it passes through the roadside optical beacon head 2, the uplink is repeated with a period A, and the success or failure of the uplink is recorded until it passes through the roadside optical beacon head 2 N times. Since the vehicle speed when passing through the roadside optical beacon head 2 is not always constant, for example, the success or failure of the uplink is recorded in association with the distance from the first downlink position. The uplink success position specifying unit 13a specifies a position where the uplink is likely to succeed and a position where the uplink is likely to fail from the N times of passing results, and stores the position in the uplink position storage unit 13c.

  FIG. 5A is a diagram illustrating an example of success or failure of the stored uplink. According to FIG. 5A, it can be seen that the uplink is likely to succeed at distances a and c from the downlink position S. The uplink position control means 13b refers to the success / failure record as shown in FIG. 5 (a), and starts the uplink from the successful uplink position a closest to the first downlink position S. Control timing.

  FIG. 5B is a diagram illustrating an example of the position where the uplink position control unit 13b performs uplink when the success / failure record of FIG. 5A is obtained. Since uplink is normally performed periodically, the uplink position control means 13b performs uplink at a period later than the period A (for example, the conventional period B). Since the uplink is started in the period B from the uplink position a, the uplink can be reliably performed at a successful position. Therefore, it is not necessary to increase the uplink period, the deterioration of the optical element can be reduced, and the position can be evaluated with high accuracy.

  FIG.5 (c) is a figure which shows another example of the success or failure of the stored uplink. According to FIG.5 (c), it turns out that an uplink is easy to succeed at the distance of c and d from the downlink position S. FIG. The uplink position control means 13b refers to the success / failure record as shown in FIG. 5 (c), and starts the uplink from the successful uplink position c closest to the first downlink position S. Control timing.

  FIG. 5D is a diagram illustrating an example of a position where the uplink position control unit 13b performs uplink when the success / failure record of FIG. 5C is obtained. In FIG.5 (c), since the success position of an uplink is adjoining, in order to perform uplink several times, it uplinks with a period (for example, period A) earlier than the period B. FIG. Since the number of uplinks is the same even if the period is earlier than that of the conventional one, the deterioration of the optical element can be suppressed, and the uplink can be reliably performed, and the position can be accurately evaluated. In addition, since it is known that it succeeds at the uplink position c, the uplink may be performed only at the uplink position c.

  FIG. 5E is a diagram illustrating another example of the success or failure of the stored uplink. According to FIG. 5 (e), it can be seen that the uplink is likely to succeed at a distance from the downlink position S to b. The uplink position control means 13b refers to the success / failure record as shown in FIG. 5E and controls the uplink timing so that the uplink is started at the uplink position b.

  FIG. 5 (f) is a diagram showing an example of the position where the uplink position control means 13b performs uplink when the success / failure record of FIG. 5 (e) is obtained. As shown in FIG. 5E, when the number of successful uplink positions is small, uplink is reliably performed at the uplink position b. To do. In the case of FIG. 5 (f), since the position of the uplink is limited and the number of times is small, the deterioration of the optical element can be reduced, and the uplink is reliably performed at the position that succeeds, so that the position can be evaluated with high accuracy. In addition, since it is known that it succeeds at the uplink position b, the uplink may be performed only at the uplink position b.

  The position evaluation by uplink will be described. FIG. 6 is a diagram showing a state in which the vehicle 1 is uplinked to the roadside optical beacon head 2 in front of the intersection and evaluated for position. When the communication device 3 enters the optical beacon area and receives the first downlink, the communication device 3 uplinks at a position controlled by the uplink position control means 13b. Since this uplink position is a position that is surely successful, the communication device 3 can receive the distance (L [m]) from the roadside optical beacon head to the stop line 20, the state of the traffic signal, and the like on the downlink.

  Since the communication device 3 sends the traffic information received on the downlink to the navigation system 18, the position rating means 18a indicates that there is an intersection (stop line 20) at a distance L from the position where the downlink for the uplink is received. To detect. The distance L to the stop line is corrected based on the uplink position unique to the vehicle. The point where the position is evaluated may be an uplink point or a point where a downlink is received with respect to the uplink.

  Since the position coordinates of the intersection can be acquired from the map database, the position evaluation means 18a corrects the position detected by the GPS or the like, assuming that the vehicle is traveling at a distance L from the intersection. That is, the position of the vehicle 1 can be corrected with high accuracy each time it passes through the roadside optical beacon head 2.

  Further, the position rating means 18a measures the distance traveled from the position where the downlink is received by the vehicle speed sensor 17. When the vehicle 1 travels a distance L, the vehicle reaches the stop line 20. Therefore, if the vehicle 1 does not decelerate even when the predetermined distance is reached, the brake ECU 19 or the like is requested to alert or decelerate. That is, intervention control based on the position of the vehicle 1 detected with high accuracy in the infrastructure cooperation system is possible. Note that the position rating means 18a may be included in the control unit 13.

  According to this embodiment, the position of the vehicle 1 can be accurately evaluated by the uplink, and the position accuracy required for the infrastructure cooperation system can be realized. Even if the accuracy of the position is improved, the uplink period is about the same as or lower than that in the prior art, so that it is possible to prevent an excessive load on the optical element.

It is a figure which shows an example of communication of the roadside apparatus and vehicle in communication which used the optical beacon as a medium. It is a figure which shows an example of the period of an uplink. It is a figure which shows an example of the success or failure of an uplink, and an uplink position. It is an example of the schematic block diagram of the road-to-vehicle communication system which used the optical beacon as a medium. It is a figure which shows an example of the success or failure of an uplink, and an uplink position. It is a figure which shows a mode that a vehicle uplinks to the roadside optical beacon head in front of an intersection, and positions are evaluated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Roadside optical beacon head 3 Communication apparatus 4 Roadside apparatus 11 Optical element 12 Drive circuit 13 Control part 14 Comparator
15 Amplifier 16 Photodiode 17 Vehicle speed sensor 18 Navigation system

Claims (7)

In a vehicle communication device that communicates with a roadside beacon head,
An uplink success position specifying means for specifying an uplink failure position and a success position;
Uplink position storage means for storing at least one of the failed position or the successful position specified by the uplink successful position specifying means;
Uplink position control means for starting an uplink from the successful position ;
A communication apparatus comprising: The uplink success position specifying means performs uplink in a predetermined cycle, specifies the failure position and the success position,
The uplink position control means uplinks at a cycle shorter than the cycle at the successful position.
The communication apparatus according to claim 1.   The communication apparatus according to claim 1, wherein the uplink position control unit prohibits uplink at the failed position.   The communication apparatus according to claim 1, wherein the uplink position control means performs uplink only at the successful position. The uplink position control means starts an uplink from the successful position closest to the beginning of an area where downlink communication with the roadside beacon head is possible .
The communication apparatus according to claim 1. An uplink means for uplinking to a roadside beacon head;
An uplink success position specifying means for specifying an uplink failure position and a success position;
Uplink position storage means for storing at least one of the failed position or the successful position specified by the uplink successful position specifying means;
Uplink position control means for starting an uplink from the successful position ;
Position assessment means for detecting the position of the moving body at a point where the downlink transmitted from the beacon head is received after the uplink;
A position detecting device comprising: In the road-to-vehicle communication system that performs road-to-vehicle communication between the roadside and the vehicle,
The roadside includes a beacon head that communicates with the vehicle by a beacon,
The vehicle has an uplink success position specifying means for specifying a failure position and a success position when uplinked to the beacon head;
Uplink position storage means for storing at least one of the failed position or the successful position specified by the uplink successful position specifying means;
Uplink position control means for starting an uplink from the successful position ;
A road-vehicle communication system characterized by comprising:

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