JP6659748B2 - Optical beacon - Google Patents

Description

  The present invention relates to an optical beacon having both a two-way communication function with an in-vehicle device and a vehicle sensing function.

  Information such as traffic congestion and traffic regulation is very important for vehicles running on roads. Therefore, an information communication system in which road traffic information such as traffic congestion and traffic regulation edited and processed at a VICS (registered trademark) center is transmitted to a vehicle and displayed on a vehicle-mounted device using characters and graphics has been put to practical use. As one of means for transmitting the road traffic information to the vehicle, an optical beacon is used.

  The optical beacon is the main equipment for realizing the new traffic management system (UTMS). It is possible to construct an optimal road-to-vehicle system for narrow roads. It is small and easy to install and handle. No license under the Radio Law is required. It has features such as low cost.

  The optical beacon emits near-infrared light having extremely high directivity from a high place toward a road. In addition, the device has both a vehicle sensing function of detecting a traveling vehicle by receiving reflected light from the vehicle and a two-way communication function with an in-vehicle device of the traveling vehicle.

  In two-way communication, light for transmitting information from the optical beacon to the on-vehicle device is referred to as downlink light, and light for transmitting information from the on-vehicle device to the optical beacon is referred to as uplink light. The light used by the optical beacon for detecting the traveling vehicle is referred to as sensing light. Further, an area where the in-vehicle device can receive the downlink light is called a downlink area, and an area where the optical beacon can receive the uplink light is called an uplink area.

  In recent years, while increasing communication capacity and increasing information collected from vehicles using uplink light, advanced optical beacons with expanded uplink and downlink areas have been put into practical use, and vehicles equipped with advanced It offers new services.

  On the other hand, the advanced optical beacon has been developed to enable communication using the conventional uplink speed of communication speed and transmission of downlink information in the conventional downlink area in order to ensure compatibility with the conventional in-vehicle device. Has become.

JP-A-10-213662

  As shown in FIG. 8A, a downlink light 501 and a sensing light 502 are emitted toward the road from an optical beacon light emitting / receiving device 500, and a downlink area DA1 capable of receiving the downlink light 501 and a vehicle detection. Possible sensing areas SA are provided according to the rules.

  In the conventional optical beacon, the downlink area DA1 and the sensing area SA are separated from each other, but in the advanced optical beacon light emitting and receiving device 510, the downlink area DA2 is enlarged. As shown in (1), there is an area IA where the downlink area DA2 and the sensing area SA overlap.

  Since both the downlink light 501 and the sensing light 502 use near infrared rays, in the area IA, there is a problem that the sensing light 502 interferes with the downlink light 501 and causes a decrease in downlink communication quality. I have.

  Therefore, an object of the present invention is to reduce interference of sensing light used for vehicle detection with downlink light in an optical beacon.

In order to solve the above problem, an optical beacon according to one embodiment of the present invention is an optical beacon that performs communication with an in-vehicle device using communication light and detects a traveling vehicle using sensing light, and the communication light A light emitting unit for communication that emits light, a first light emitting unit for sensing that emits the sensing light, and irradiation farther from an irradiation region of the light emitting unit for communication than an irradiation region of the first light emitting unit for sensing. A second light emitting unit for sensing the area, and a sensing control unit for stopping light emission of the first light emitting unit for sensing when the in-vehicle device to be communicated is an advanced in-vehicle device corresponding to communication with increased capacity. It is characterized by having.
Here, the sensing control unit may cause the first sensing light emitting unit to emit light after a predetermined time has elapsed after stopping the light emission of the sensing first light emitting unit.
In addition, the sensing control unit is configured to determine whether the light emission of the first sensing light emitting unit is stopped, rather than the light amount of the second sensing light emitting unit when the first sensing light emitting unit is emitting light. The light amount of the second light emitting unit for sensing can be increased.
The apparatus further includes a sensing processing unit that measures a sensing light area occupation time of the traveling vehicle based on the reflected light of the sensing light, wherein the sensing processing unit is configured to stop emitting light of the sensing first light emitting unit. Can be corrected.
At this time, the sensing processing unit can perform the correction using a preset estimated value of the average vehicle length of the traveling vehicle.
Further, a communication control unit that determines whether or not the in-vehicle device to be communicated is the advanced in-vehicle device based on the communication light received from the in-vehicle device may be further provided.

  According to the present invention, in an optical beacon, it is possible to reduce interference of sensing light used for vehicle detection with downlink light.

It is a block diagram showing composition of an optical beacon of this embodiment. It is a figure showing an irradiation area of the 1st sensing light, and an irradiation area of the 2nd sensing light. FIG. 4 is a block diagram illustrating a configuration of a sensing light emitting driver unit that drives a first sensing light emitting unit and a second sensing light emitting unit. It is a flowchart explaining sensing light emission control of an optical beacon. FIG. 7 is a diagram illustrating a sensing light region when a communication target is a conventional vehicle-mounted device and a sensing light region when a communication target is an advanced vehicle-mounted device. It is a flowchart explaining the procedure of the correction process of an occupation time. It is a figure which illustrates typically the correction process of an occupation time. FIG. 7 is a diagram illustrating a conventional relationship between a downlink area and a sensing area.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of the optical beacon 10 according to the present embodiment. The optical beacon 10 is an advanced optical beacon having an increased communication capacity, and can perform bidirectional wireless communication with an advanced in-vehicle device mounted on a vehicle and a conventional in-vehicle device by optical communication using near-infrared light as a communication medium. it can. Further, the vehicle has a vehicle sensing function of detecting a traveling vehicle by emitting sensing light and receiving reflected light from the vehicle.

  As shown in the figure, the optical beacon 10 includes a plurality of light emitting and receiving devices 100 (100a, 100b... 100n) and a controller 200. The controller 200 includes an emitter / receiver interface unit 210 and a sensing / communication processing unit 220. The sensing / communication processing unit 220 generates a downlink signal output from the light emitter / receiver 100, performs signal processing on the uplink signal received by the light emitter / receiver 100 and a reflection signal of the sensed light, and performs communication with a higher-level device (not shown). Perform communication.

  The light emitter / receiver 100 includes a communication block and a sensing block. The communication block includes a communication light emitting unit 101, a communication light emitting driver unit 102, a communication light receiving unit 103, an amplifier 104, a filter 105, and a communication control unit 106.

  The communication control unit 106 encodes the downlink signal generated by the sensing / communication processing unit 220 and reproduces the uplink signal from the uplink light received by the communication light receiving unit 103. At this time, it is possible to determine whether the uplink signal is from the conventional vehicle-mounted device or the advanced vehicle-mounted device based on the transmission speed of the uplink signal.

  The communication light emitting unit 101 outputs downlink light by driving the communication light emitting driver unit 102 based on the control of the communication control unit 106. The communication light receiving unit 103 receives the uplink light. The light reception signal is input to the communication control unit 106 via the amplifier 104 and the filter 105. The communication control unit 106 outputs an uplink signal reproduced from the uplink light to the controller 200.

  The sensing block includes a first sensing light emitting unit 111, a second sensing light emitting unit 112, a sensing light receiving unit 113, an amplifier 114, a filter 115, a sensing control unit 116, a peak hold unit 117, and a sensing light emitting driver unit 120. It has. The sensing control unit 116 generates a sensing signal that is a pulse signal having a predetermined period.

  The first sensing light emitting unit 111 and the second sensing light emitting unit 112 output sensing light by driving the sensing light emitting driver unit 120 based on the control of the sensing control unit 116. That is, in the present embodiment, the sensing light can be output from the plurality of light emitting units.

  The sensing first light emitting unit 111 can independently switch between light emission and non-light emission. A state in which the first sensing light emitting unit 111 and the second sensing light emitting unit 112 emit light at the same time is referred to as a first sensing light emitting state. The first sensing light emitting unit 111 is turned off, and the second sensing light emitting unit is turned off. A state in which only 112 emits light is referred to as a second sensing light emission state.

  The sensing light receiving unit 113 receives reflected light of the sensing light. The light reception signal is input to the peak hold unit 117 via the amplifier 114 and the filter 115. The peak hold unit 117 outputs the held peak value to the controller 200 as a reflected signal of the sensing light.

  In the present embodiment, the irradiation area is different between the first sensing light emitting state and the second sensing light emitting state. Specifically, as shown in FIG. 2, the irradiation area 302 (dotted line) in the second sensing light emitting state in which only the second sensing light emitting unit 112 emits light includes the first sensing light emitting unit 111 and the sensing light emitting unit 111. This is an irradiation area farther from the downlink areas (DA1, DA2) than the irradiation area 301 (solid line) in the first sensing light emission state where the second light emitting unit 112 emits light simultaneously. This is because the irradiation area of the first sensing light emitting unit 111 extends upstream (downlink area side) from the irradiation area of the second sensing light emitting unit 112.

  The irradiation area 301 in the first sensing light emission state is set to be the same as the conventional sensing area SA. The irradiation area 301 in the first sensing light emitting state has a portion that overlaps with the downlink area DA2 when communicating with the advanced in-vehicle device, whereas the irradiation area 302 in the second sensing light emitting state has , Do not overlap with the downlink area DA2. The reason why the downstream end of the irradiation area 301 in the first sensing light emitting state does not match the downstream end of the irradiation area 302 in the second sensing light emitting state will be described later.

  The first light emitting unit for sensing 111 and the second light emitting unit for sensing 112 are respectively arranged by, for example, arranging an optical element such as a prism or a lens whose angle is adjusted on each of a plurality of LEDs arranged in an array. Can be set.

  FIG. 3 is a block diagram illustrating a configuration of the sensing light emitting driver unit 120 that drives the sensing first light emitting unit 111 and the sensing second light emitting unit 112. As shown in the figure, the sensing light emitting driver unit 120 drives the first sensing light emitting unit 111 with the current Ia and drives the second sensing light emitting unit 112 with the current Ib or the current Ic.

  The current Ia is controlled by a resistor A121a and a switch A122a (path A), the current Ib is controlled by a resistor B121b and a switch B122b (path B), and the current Ic is controlled by a resistor C121c and a switch C122c (path C). You. On / off of the switch A 122a, the switch B 122b, and the switch C 122c is controlled by the sensing control unit 116.

  Here, the resistance B121b and the resistance C121c have different resistance values, and the second light emitting unit for sensing 112 has a different light amount when the switch B122b is turned on and when the switch C122c is turned on. . Details will be described later. Note that it is sufficient that the amount of light of the second light emitting unit for sensing 112 can be controlled in two ways, and the control path of the second light emitting unit for sensing 112 is not limited to the example in this drawing.

  Next, the sensing light emission control of the optical beacon 10 having the above configuration will be described with reference to the flowchart of FIG.

  In normal times, the sensing control unit 116 simultaneously emits the sensing first light emitting unit 111 and the sensing second light emitting unit 112 as sensing light (S101). That is, the irradiation area 301 in the first sensing light emission state shown in FIG. 2 is the sensing light area. This is the same area as the conventional sensing light area SA.

  When the communication light receiving unit 103 receives the uplink light (S102: Yes), the communication control unit 106 determines whether the communication target is an advanced in-vehicle device or a conventional in-vehicle device based on the transmission speed of the received signal. It is determined whether there is.

  As a result, if the communication target is the conventional in-vehicle device (S103: No), the first light emitting unit for sensing 111 and the second light emitting unit for sensing 112 continue to emit light simultaneously (S101). This is because, as shown in FIG. 5A, the irradiation area 301 in the first sensing light emitting state does not overlap with the downlink area DA1 for the conventional in-vehicle device, so that the sensing light interferes with the downlink light. Because there is no.

  On the other hand, if the communication target is the advanced in-vehicle device (S103: Yes), the sensing control unit 116 turns off the switch A 122a to stop the light emission of the first sensing light emitting unit 111, and causes the second sensing light emitting unit 112 to emit light. Only the second sensing light is emitted. As shown in FIG. 5B, the irradiation area 302 in the second sensing light emission state does not overlap with the downlink area DA2 for the in-vehicle advanced device, so that the sensing light does not interfere with the downlink light.

  The light emission of only the second light emitting unit for sensing 112 continues for a predetermined time (S105), and thereafter, the simultaneous light emission of the first light emitting unit for sensing 111 and the second light emitting unit for sensing 112 is restarted (S101).

  As described above, in the optical beacon 10 of the present embodiment, the first light emitting unit for sensing 111 and the second light emitting unit for sensing 112 are usually emitted at the same time, and the first light emitting for sensing is performed at the time of communication with the advanced in-vehicle device. Although the light emission of the unit 111 is stopped and only the second sensing light emitting unit 112 emits light, it is not preferable that the intensity of the reflected light to be received is reduced when the light emission is switched to the light emission of only the second sensing light emitting unit 112. .

  Therefore, in the optical beacon 10, as described above, the light amount of the second sensing light emitting unit 112 is different between when the switch B122b is turned on and when the switch C122c is turned on.

  In the process (S101), when the first sensing light emitting unit 111 and the second sensing light emitting unit 112 emit light simultaneously, the switch A 122a (path A) and the switch B 122b (path B) shown in FIG. Is turned on, and the switch C122c (path C) is turned off. The amount of reflected light from the road surface or the like obtained at this time is P1.

  In the process (S104), when the second light emitting unit for sensing 112 emits light alone, the switch A 122a (path A) and the switch B 122b (path B) shown in FIG. 3 are turned off, and the switch C 122c ( Turn on the path C). The amount of reflected light from the road surface or the like obtained at this time is P2.

  Here, the values of the resistors A121a, B121b, and C121c are determined so that the amount of reflected light P1 and the amount of reflected light P2 are substantially the same. At least in the relationship between the resistances B121b and C121c, the resistance C121c is made smaller than the resistance B1121b so that the current Ic is larger than the current Ib. Accordingly, the light amount of the second sensing light emitting unit 112 when emitting light alone can be made larger than when emitting light simultaneously with the first sensing light emitting unit 111. As a result, the downstream end of the irradiation region 302 in the second sensing light emitting state extends downstream from the downstream end of the irradiation region 301 in the first sensing light emitting state.

  By the way, the sensing / communication processing unit 220 of the controller 200 generally measures the occupation time of the detection target vehicle in the sensing light area when detecting the traveling vehicle based on the reflected light of the sensing light. In the optical beacon 10 of the present embodiment, the light emission of the sensing first light emitting unit 111 is stopped and the light emission of only the sensing second light emitting unit 112 is stopped for the vehicle equipped with the advanced in-vehicle device. The width of the region in the running direction is reduced. For this reason, if the measured occupation time is used as it is, the occupation time will be shorter than the occupation time measured in the conventional sensing light region.

  Therefore, for example, it is desirable to perform the occupation time correction processing as shown in the flowchart of FIG. That is, when the sensing / communication processing unit 220 detects the traveling vehicle by the reflected light of the sensing light (S201: Yes), the sensing / communication processing unit 220 measures the occupation time of the sensing light area by the vehicle (S202). Here, the occupation time can be, for example, a time from when the intensity of the received light of the reflected light exceeds a predetermined reference value to when it falls below the predetermined reference value.

  If the vehicle does not have the advanced in-vehicle device (S203: No), there is no need to correct the occupation time, and the process waits for detection of the next running vehicle (S201). Whether or not the advanced in-vehicle device is installed can be determined based on the uplink communication speed or the like as in the process (S102).

  On the other hand, if the vehicle is equipped with an advanced in-vehicle device (S203: Yes), the occupancy time is corrected (S204). The correction of the occupation time can be performed, for example, as follows. Here, as shown in FIG. 7, the sensing light region in the first sensing light emitting state where the first sensing light emitting unit 111 and the second sensing light emitting unit 112 emit light is denoted by SA1, and the second sensing light emitting region is emitted. The sensing light area in the second sensing light emitting state where only the portion 112 emits light is defined as SA2. The sensing light area SA1 is the same as the conventional sensing light area SA.

Assuming that the occupation time measured in the sensing light area SA1 is time T1 and the occupation time measured in the sensing light area SA2 is time T2 when the vehicle of the vehicle length L passes at the speed V, time T1 and time T2 Are respectively
Time T1 = (SA1 + L) / V
Time T2 = (SA2 + L) / V
And
Time T1 / Time T2 = (SA1 + L) / (SA2 + L)
Therefore, for vehicles equipped with advanced in-vehicle devices,
Occupancy time after correction = (SA1 + L) / (SA2 + L) × time T2
It can be.

  Although the lengths of SA1 and SA2 are known, L differs for each vehicle. Since it is difficult to obtain L for each traveling vehicle in real time, the corrected occupation time is calculated from the time T2 by estimating the average value of the vehicle length L of the vehicle traveling on the road. .

  For example, the vehicle length L is divided into 3.5 m, 4 m, 4.5 m, 5 m, 9 m, 10 m, and 11 m, and the actual mixing ratio for each vehicle length L is observed, and the weighted average of the vehicle length L is obtained. Is calculated, an average value of L on the road can be obtained.

For example, when the mixing rates of 3.5 m, 4 m, 4.5 m, 5 m, 9 m, 10 m, and 11 m were observed on the road, they were 15%, 20%, 20%, 15%, 10%, and 10%, respectively. , 10%, the average value Lav of the vehicle length L is
Lav = 3.5mx15% + 4mx20% + 4.5mx20% + 5mx15% + 9mx10% + 10mx10% + 11mx10% = 5.12m
Becomes In this case, the estimated occupation time can be calculated from the measured time T2 by estimating the vehicle length L to be 5.12 m and setting it in the sensing / communication processing unit 220 in advance.

  Although the example in which the sensing light is output from the first sensing light emitting unit 111 and the second sensing light emitting unit 112 has been described, the sensing light may be output from more sensing light emitting units. Also in this case, when communicating with the advanced in-vehicle device, light emission from the sensing light emitting unit in the irradiation area overlapping with the downlink area DA2 may be stopped.

Reference Signs List 10 optical beacon 100 emitter / receiver 101 communication light emitting unit 102 communication light emitting driver unit 103 communication light receiving unit 104 amplifier 105 filter 106 communication control unit 111 first sensing light emitting unit 112 second sensing light emitting unit 113 sensing light receiving unit 114 Amplifier 115 Filter 116 Sensing control unit 117 Peak hold unit 120 Light emitting driver unit for sensing 200 Controller 210 Transmitter / receiver interface unit 220 Sensing / communication processing unit

Claims (6)

An optical beacon that performs communication with an in-vehicle device using communication light and detection of a traveling vehicle using sensing light,
A communication light emitting unit for emitting the communication light,
A first light emitting unit for sensing that emits the sensing light, and a second light emitting unit for sensing of an irradiation area farther from the irradiation area of the communication light emitting unit than the irradiation area of the first light emitting unit for sensing;
In the case where the in-vehicle device to be communicated is an advanced in-vehicle device corresponding to communication with increased capacity, a sensing control unit that stops emitting light from the first light emitting unit for sensing,
An optical beacon comprising:   The optical beacon of claim 1, wherein the sensing control unit causes the first sensing light emitting unit to emit light after a lapse of a predetermined time after the emission of the sensing first light emitting unit is stopped.   The sensing control unit is configured to perform the sensing when the first sensing light emitting unit stops emitting light, more than the light amount of the second sensing light emitting unit when the first sensing light emitting unit emits light. The optical beacon according to claim 1, wherein a light amount of the second light emitting unit is increased. Further comprising a sensing processing unit that measures the sensing light area occupancy time of the traveling vehicle based on the reflected light of the sensing light,
4. The sensing processing unit according to claim 1, wherein the sensing processing unit corrects a sensing light area occupation time measured when the first sensing light emitting unit stops emitting light. 5. Light beacon.   The optical beacon according to claim 4, wherein the sensing processing unit performs the correction using a preset estimated value of the average length of the traveling vehicle.   The communication control unit according to claim 1, further comprising a communication control unit configured to determine whether an in-vehicle device to be communicated is the advanced in-vehicle device based on communication light received from the in-vehicle device. An optical beacon according to claim 1.

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