JP5641961B2 - Radio wave emission source detection sensor and automatic toll collection system - Google Patents

Description

  An embodiment of the present invention relates to a radio wave emission source detection sensor that determines a travel lane of a vehicle traveling on a toll road, for example, and an automatic fee collection system that uses this sensor.

  ETC (Electronic) is a technology that automatically collects tolls on toll roads without stopping the vehicle by communicating between roadside devices installed at toll road tolls and on-board devices mounted on vehicles. Toll Collection) exists. ETC was developed to reduce the cost required to collect tolls and to alleviate the frequent traffic congestion at toll booths.

  However, in the conventional automatic toll collection system, radio waves are reflected by surrounding structures and the like, so that a roadside device installed in a predetermined ETC lane and an in-vehicle device installed in a vehicle existing in an adjacent lane are erroneous. There is a risk of communication. In such a case, there is a possibility that the roadside device will make an erroneous charge for the vehicle-mounted device in the adjacent lane.

JP 2008-108146 A

  As described above, in the conventional automatic toll collection system, the roadside device installed in a predetermined lane and the vehicle-mounted device existing in the adjacent lane may cause erroneous communication.

  Therefore, the purpose is to cancel the erroneous communication established between the roadside device installed in a predetermined lane and the vehicle-mounted device existing in the adjacent lane, and to prevent erroneous charges for the vehicle-mounted device. An object of the present invention is to provide a launch source detection sensor and an automatic toll collection system using the sensor.

  According to the embodiment, the radio wave emission source detection sensor connected to the first and second roadside devices that are installed in the first and second lanes and communicate with the transponder possessed by the moving body includes the antenna unit, A detection unit, a direction specifying unit, and an erroneous communication determination unit are provided. The antenna unit receives a response signal from the responder by a reception beam including the first and second lanes. The detector detects a necessary signal from the response signal based on the reception frequency of the first or second roadside device. The direction specifying unit measures the radio field intensity of the necessary signal based on the detection result, specifies the arrival direction of the response signal, and specifies the response frequency of the response signal. The miscommunication determination unit is configured so that a response frequency of a response signal that arrives from the first or second lane and whose radio field intensity exceeds a preset threshold is based on the radio field intensity, the arrival direction, and the response frequency. If it is determined that the received frequency of the first or second roadside device is not compatible, an erroneous communication notification that the communication with the responder is in error is output to the first and second roadside devices. To do.

It is a figure which shows an example of a structure with the automatic fee collection system which concerns on 1st Embodiment, and the ETC onboard equipment mounted in the vehicle. It is a block diagram which shows an example of a function structure with the roadside device of FIG. 1, a radio wave emission source detection sensor, and an ETC onboard equipment. It is a figure which shows an example of the 2nd receiving area by the radio wave emission source detection sensor of FIG. It is a block diagram which shows an example of a function structure of the determination process part of FIG. It is a figure which shows an example of the identification of the lane by the miscommunication determination part of FIG. It is a figure which shows an example of the miscommunication determination process by the miscommunication determination part of FIG. It is a figure which shows an example of the miscommunication determination process by the miscommunication determination part of FIG. It is a figure which shows an example of the miscommunication determination process by the miscommunication determination part of FIG. It is a figure which shows an example of the miscommunication determination process by the miscommunication determination part of FIG. It is a figure which shows an example of the miscommunication determination process by the miscommunication determination part of FIG. It is a figure which shows an example in case the roadside device of FIG. 1 communicates with the ETC vehicle-mounted device mounted in the vehicle which drive | works an adjacent lane. It is a sequence diagram which shows an example of operation | movement of the roadside device and radio wave emission source detection sensor of FIG. It is a figure which shows an example of the structure of the radio wave emission source detection sensor of FIG. It is a figure which shows the other example of a structure with an automatic fee collection system and the ETC onboard equipment mounted in the vehicle. It is a figure which shows an example at the time of seeing the 2nd receiving beam formed by the radio wave emission source detection sensor of FIG. 14 from the front of a lane. It is a figure which shows an example of the 2nd receiving area of the radio wave emission source detection sensor of FIG.

  Hereinafter, embodiments will be described with reference to the drawings. In the following embodiment, an example in which a radio wave emission source detection sensor is used in an ETC (Electronic Toll Collection) system will be described. However, a system that uses a radio wave emission source detection sensor is not limited to an ETC system.

(First embodiment)
FIG. 1 is an example of a schematic diagram illustrating configurations of an automatic fee collection system 10 according to the first embodiment and an ETC on-vehicle device 20 mounted on a vehicle V.

  An automatic fee collection system 10 shown in FIG. 1 is a system that conforms to the ARIB (Association of Radio Industries and Businesses) STD-T55 standard. The automatic toll collection system 10 includes a gantry 11, roadside devices 12-1 and 12-2, vehicle detectors 13-1, 13-2 to 15-1, 15-2, a signal processing unit 16, and a radio wave emission source detection sensor 17. Is provided.

  The gantry 11 is installed so as to straddle the ETC lanes 1 and 2. The gantry 11 is attached with roadside devices 12-1 and 12-2 and a radio wave emission source detection sensor 17. The roadside devices 12-1 and 12-2 are attached almost directly above the ETC lanes 1 and 2, respectively. The radio wave emission source detection sensor 17 is attached almost directly above the island, which is substantially in the middle between the roadside devices 12-1 and 12-2. Since ETC lane 1 and ETC lane 2 have the same configuration, ETC lane 1 will be described below.

  The vehicle detectors 13-1 to 15-1 detect the passing vehicle V and notify the roadside device 12-1 that the vehicle V has been detected.

  The roadside device 12-1 forms a transmission beam so as to transmit a notification signal for notifying the start of communication to a predetermined area in its own lane. Moreover, the roadside device 12-1 forms a 1st receiving beam so that the response signal from the ETC vehicle-mounted device 20 which exists in the 1st receiving area of an own lane may be received.

  When the vehicle detector 13-1 detects the vehicle V, the roadside device 12-1 transmits a notification signal at a preset frequency toward a predetermined area in its own lane. Note that the roadside device 12-1 always transmits some signal, and when the vehicle detector 13-1 detects the vehicle V, even if the signal is switched so as to transmit a signal notifying the start of communication. I do not care. When receiving the notification signal from the roadside device 12-1, the ETC on-vehicle device 20 returns a response signal having a frequency corresponding to the frequency of the notification signal to the roadside device 12-1. The roadside device 12-1 receives the response signal from the ETC vehicle-mounted device 20.

  The roadside device 12-1 outputs a synchronization signal to the radio wave emission source detection sensor 17. Thereby, the radio wave emission source detection sensor 17 is synchronized with the roadside device 12-1. The radio wave emission source detection sensor 17 may receive the notification signal from the roadside device 12-1, and may synchronize with the roadside device 12-1 based on this notification signal.

  When the roadside device 12-1 receives the response signal from the ETC on-vehicle device 20, the roadside device 12-1 starts communication with the ETC on-vehicle device 20. At this time, the roadside device 12-1 performs the billing process for the ETC vehicle-mounted device 20 together with the signal processing unit 16.

  When the roadside device 12-1 receives an erroneous communication notification described later from the radio wave emission source detection sensor 17, the roadside device 12-1 determines that the ETC vehicle-mounted device 20 exists in another lane, ends communication with the ETC vehicle-mounted device 20, and The charging process for the vehicle-mounted device 20 is interrupted.

  When the vehicle detector 14-1 detects the vehicle V after the vehicle detector 13-1 detects the vehicle V, the roadside device 12-1 recognizes that the vehicle V is moving forward. Further, when the vehicle detector 15-1 detects the vehicle V, the roadside device 12-1 recognizes that the vehicle V has passed through its own lane.

  FIG. 2 is a block diagram illustrating an example of functional configurations of the roadside devices 12-1 and 12-2 and the radio wave emission source detection sensor 17 and the ETC on-vehicle device 20 according to the first embodiment.

  As shown in FIG. 2, the radio wave emission source detection sensor 17 includes an antenna unit 171, a reception unit 172, and a determination processing unit 173.

  The antenna unit 171 includes, for example, a plurality of antenna elements arranged vertically and horizontally. The radio wave emission source detection sensor 17 forms a second reception beam by the plurality of antenna elements. In the present embodiment, the beam width in the elevation angle direction is set to be, for example, 45 degrees or less by narrowing the beam of the antenna elements arranged in the vertical direction. Further, the beam width in the azimuth direction is set to be, for example, ± 90 degrees by setting the lateral distance between the antenna elements to 0.5λ, for example. Accordingly, a range of 5 m from the position immediately below the radio wave emission source detection sensor 17 toward the entrance of the ETC lanes 1 and 2 becomes the second reception area. The hatched area shown in FIG. 3 shows an example of the second reception area according to the first embodiment. The second reception beam has a wider beam width than the first reception beam, and the second reception area is wider than the first reception area. The antenna unit 171 receives the response signal using the second reception beam.

  The receiving unit 172 converts the response signal received by the antenna unit 171 into an IF signal in the intermediate frequency band, and outputs the IF signal to the determination processing unit 173.

  FIG. 4 is a block diagram illustrating an example of a functional configuration of the determination processing unit 173 of the radio wave emission source detection sensor 17 according to the first embodiment. The determination processing unit 173 includes a CPU (Central Processing Unit) made of, for example, a microprocessor, and is configured as follows. That is, the determination processing unit 173 includes a detection unit 1731, a direction specifying unit 1732, and an erroneous communication determination unit 1733.

  The detection unit 1731 detects a necessary signal from the IF signal from the reception unit 172 based on the synchronization signal from the roadside device 12-1. At this time, the detection unit 1731 detects a necessary signal at a detection frequency corresponding to the reception frequency of the roadside device 12-1. The detection unit 1731 outputs the detection result to the direction specifying unit 1732 as the first detection result. The detection unit 1731 detects a necessary signal from the IF signal from the reception unit 172 based on the synchronization signal from the roadside device 12-2. At this time, the detection unit 1731 detects a necessary signal at a detection frequency corresponding to the reception frequency of the roadside device 12-2. The detection unit 1731 outputs the detection result to the direction specifying unit 1732 as the second detection result.

  The direction specifying unit 1732 measures the radio field intensity based on the first and second detection results from the detection unit 1731. The direction specifying unit 1732 acquires the first radio wave intensity information based on the first detection result, and acquires the second radio wave intensity information based on the second detection result. The direction specifying unit 1732 outputs the first and second radio wave intensity information to the erroneous communication determination unit 1733.

  In addition, the direction specifying unit 1732 specifies the arrival direction of radio waves in the azimuth direction based on the first and second detection results. The direction specifying unit 1732 acquires first arrival direction information based on the first detection result, and acquires second arrival direction information based on the second detection result. The direction specifying unit 1732 outputs the first and second arrival direction information to the erroneous communication determination unit 1733.

  Further, the direction specifying unit 1732 specifies the response frequency of the signal based on the first and second detection results. The direction specifying unit 1732 acquires the first frequency information based on the first detection result, and acquires the second frequency information based on the second detection result. The direction specifying unit 1732 outputs the first and second frequency information to the erroneous communication determination unit 1733.

  As shown in FIG. 5, the erroneous communication determination unit 1733 uses the first and second arrival direction information to determine whether the response signal received by the antenna unit 171 is a signal from one of the ETC lanes 1 and 2. to decide. For example, in this embodiment, signals with an elevation angle of 45 degrees or less and azimuth angles of +5 to +35 degrees are signals from ETC lane 1, and signals with an elevation angle of 45 degrees or less and −35 to -5 degrees are signals from ETC lane 2. Assume that the other signals are signals from other lanes.

  Further, the miscommunication determination unit 1733 determines whether or not the radio wave intensity of the response signal received by the antenna unit 171 exceeds a preset threshold, using the first and second radio wave intensity information.

  In addition, the erroneous communication determination unit 1733 uses the first and second frequency information, and the response frequency of the response signal received by the antenna unit 171 corresponds to any of the reception frequencies of the roadside devices 12-1 and 12-2. Judge whether to do. The erroneous communication determination unit 1733 uses these determination results to determine whether or not the roadside devices 12-1 and 12-2 are performing erroneous communication.

  A specific determination method will be described with reference to FIGS.

  The erroneous communication determination unit 1733 determines whether the response signal arriving from the ETC lane 1 corresponds to the reception frequency of the roadside device 12-1 and the radio wave intensity exceeds a preset threshold value. As illustrated in FIG. 6, when the erroneous communication determination unit 1733 determines that the response signal arriving from the ETC lane 1 corresponds to the reception frequency of the roadside device 12-1 and the radio wave intensity exceeds the threshold value, It is determined that the communication with the device 20 is “normal”. In addition, the erroneous communication determination unit 1733 determines whether the response signal arriving from the ETC lane 2 corresponds to the reception frequency of the roadside device 12-2 and the radio wave intensity exceeds a preset threshold value. As illustrated in FIG. 6, when the erroneous communication determination unit 1733 determines that the response signal arriving from the ETC lane 2 corresponds to the reception frequency of the roadside device 12-2 and the radio field intensity exceeds the threshold value, It is determined that the communication with the device 20 is “normal”.

  In addition, as illustrated in FIG. 7, when the erroneous communication determination unit 1733 determines that the response signal arriving from the ETC lane 1 corresponds to the reception frequency of the roadside device 12-2 and the radio field intensity exceeds the threshold value, It is determined that the communication with the ETC on-vehicle device 20 is “error”. In addition, as illustrated in FIG. 7, when the erroneous communication determination unit 1733 determines that the response signal arriving from the ETC lane 2 corresponds to the reception frequency of the roadside device 12-1 and the radio field intensity exceeds the threshold value, It is determined that the communication with the ETC on-vehicle device 20 is “error”. In addition, as shown in FIG. 8, when the erroneous communication determination unit 1733 determines that the response signal comes from other than the ETC lanes 1 and 2 and the radio field intensity exceeds the threshold, the communication with the ETC on-vehicle device 20 is performed. It is determined that it is an “error”. When the erroneous communication determination unit 1733 determines that the communication with the ETC on-vehicle device 20 is “error”, the erroneous communication determination unit 1733 outputs an erroneous communication notification to the roadside devices 12-1 and 12-2.

  In addition, as illustrated in FIG. 9, the erroneous communication determination unit 1733 determines that the response signal comes from a plurality of directions of the ETC lanes 1 and 2 and that the radio wave intensity exceeds the threshold value, It is determined that the communication is “not determined”. In the case as shown in FIG. 9, the erroneous communication determination unit 1733 determines that the communication with the ETC on-vehicle device 20 is an error, and outputs an erroneous communication notification to the roadside devices 12-1 and 12-2. It doesn't matter. Further, as illustrated in FIG. 10, the erroneous communication determination unit 1733 determines that the communication with the ETC on-vehicle device 20 is “determination impossible” when the radio wave intensity does not exceed the threshold.

  Next, operations of the roadside devices 12-1 and 12-2 and the radio wave emission source detection sensor 17 in the automatic toll collection system 10 configured as described above will be described in detail. FIG. 11 is a schematic diagram illustrating an example of a case where the ETC in-vehicle device 20-2 mounted on the vehicle V2 traveling on the ETC lane 2 communicates with the roadside device 12-1.

  In FIG. 11, the roadside device 12-1 transmits a notification signal of the frequency f1 and receives a response signal of the frequency f1. The roadside device 12-2 transmits a notification signal having the frequency f2 and receives a response signal having the frequency f2. The radio wave emission source detection sensor 17 detects a necessary signal corresponding to the frequency f1 and the frequency f2 from the IF signal from the reception unit 172 by the detection unit 1731.

  In FIG. 11, the notification signal transmitted from the roadside device 12-1 at the frequency f1 is reflected by the vehicle V1 traveling on the ETC lane 1 and received by the ETC onboard device 20-2 mounted on the vehicle V2. The ETC vehicle-mounted device 20-2 transmits a response signal having the frequency f1 in response to the notification signal having the frequency f1. Thereby, communication between the roadside device 12-1 and the ETC vehicle-mounted device 20-2 is started.

  12 shows the start of the charging process for the ETC on-board unit 20-2 by the roadside device 12-1 shown in FIG. 11, the interruption of the charging process for the ETC onboard unit 20-2 by the roadside unit 12-1, and the roadside unit 12- 2 is a sequence diagram showing operations of roadside devices 12-1 and 12-2 and radio wave emission source detection sensor 17 when searching for a new communication partner according to 1 and 12-2.

  The roadside devices 12-1 and 12-2 output a synchronization signal to the radio wave emission source detection sensor 17 every predetermined period.

  When the roadside device 12-1 receives a notification that the vehicle V1 has been detected from the vehicle detector 13-1 (sequence S121), a notification signal such as an FCMS (Frame Control Message Slot) signal and an MDS (Message Data Slot) signal. Is transmitted at a frequency f1 to a predetermined area in the own lane (sequence S122). When roadside device 12-2 receives notification from vehicle detector 13-2 that vehicle V2 has been detected (sequence S123), roadside device 12-2 transmits a notification signal at a frequency f2 to a predetermined area in its own lane (sequence). S124).

  In FIG. 11, the notification signal from the roadside device 12-1 is reflected by the vehicle V <b> 1 and received by the ETC on-vehicle device 20-2 mounted on the vehicle V <b> 2. When receiving the notification signal having the frequency f1, the ETC on-vehicle device 20-2 transmits a response signal such as an ACTS (Activation Slot) signal, an ACCC (Activation Channel) signal, or an MDS signal at the frequency f1.

  The roadside device 12-1 receives the response signal from the ETC vehicle-mounted device 20-2 (sequence S125), starts communication with the ETC vehicle-mounted device 20-2, and starts charging processing for the ETC vehicle-mounted device 20-2. (Sequence S126).

  The radio wave emission source detection sensor 17 receives the response signal from the ETC vehicle-mounted device 20-2 (sequence S127), and the detection unit 1731 transmits, for example, the ACTS signal of the frequency f1 included in the response signal from the roadside device 12-1. Is detected in synchronization with the synchronization signal (sequence S128). Based on the first detection result, the radio wave emission source detection sensor 17 acquires the first radio wave intensity information, the first arrival direction information, and the first frequency information by the direction specifying unit 1732 (sequence S129). Then, the radio wave emission source detection sensor 17 is configured so that the roadside device 12-1 and the ETC on-vehicle device are detected by the erroneous communication determination unit 1733-1 based on the first radio wave intensity information, the first arrival direction information, and the first frequency information. It is determined whether or not 20-2 is performing erroneous communication (sequence S1210). When the result shown in FIG. 7 is obtained, the radio wave emission source detection sensor 17 determines that the roadside device 12-1 and the ETC in-vehicle device 20-2 are performing erroneous communication, and the roadside devices 12-1, 12 -2 is notified of erroneous communication (sequence S1211).

  When the roadside device 12-1 receives the erroneous communication notification from the radio wave emission source detection sensor 17, the roadside device 12-1 interrupts the billing process for the ETC on-vehicle device 20-2 and transmits the notification signal again at the frequency f1 (sequence S1212).

  When the roadside device 12-2 receives an erroneous communication notification from the radio wave emission source detection sensor 17 in a state where there is no response signal from the vehicle V2 to the notification signal transmitted in sequence S124, the roadside device 12-2 transmits the notification signal again at the frequency f2 ( Sequence S1213).

  Next, an embodiment of the above-described radio wave emission source detection sensor 17 is shown in FIG. FIG. 13 is a diagram illustrating an example of the structure of the radio wave emission source detection sensor 17 according to the first embodiment.

  The radio wave emission source detection sensor 17 in FIG. 13 includes antenna elements 176-1 to 176-n serving as an antenna unit 171 and a receiving unit 172 in a casing covered with a radome 174 on the front side and a heat radiating plate 175 on the rear side. Frequency converters 177-1 to 177-n and a local signal generation board 178 and a signal processing board 179 as a determination processing unit 173 are provided.

  The antenna elements 176-1 to 176-n receive the response signal from the ETC vehicle-mounted device 20. The frequency converters 177-1 to 177-n convert the response signals received by the antenna elements 176-1 to 176-n into IF signals based on the local signals generated by the local signal generation board 178. The signal processing board 179 receives the IF signal from the frequency converters 177-1 to 177-n, and determines whether or not the roadside devices 12-1 and 12-2 are performing erroneous communication. The signal processing board 179 outputs an erroneous communication notification to the roadside units 12-1 and 12-2 when at least one of the roadside units 12-1 and 12-2 performs the erroneous communication.

  As described above, in the above embodiment, the radio wave emission source detection sensor 17 is installed between the ETC lanes 1 and 2, and the roadside devices 12-1 and 12-2 installed in the ETC lanes 1 and 2 are erroneous. Whether or not communication is being performed is monitored. As a result, the number of radio wave emission source detection sensors required is less than that required when radio wave emission source detection sensors are installed for each lane. That is, the facility cost can be kept low.

  Moreover, in the said embodiment, the radio wave emission source detection sensor 17 detects a required signal with the detection frequency according to the reception frequency of the roadside devices 12-1 and 12-2 of ETC lanes 1 and 2 from the received response signal. . The radio wave emission source detection sensor 17 acquires radio wave intensity information, arrival direction information, and frequency information based on the first and second detection results. The radio wave emission source detection sensor 17 determines whether or not the communication with the ETC on-vehicle device 20 is “error” based on the radio wave intensity information, the arrival direction information, and the frequency information. The radio wave emission source detection sensor 17 outputs an erroneous communication notification to the roadside devices 12-1 and 12-2 when the communication with the ETC on-vehicle device 20 is “error”. Thereby, when the roadside devices 12-1 and 12-2 and the ETC in-vehicle device 20 are performing erroneous communication, it is possible to interrupt the erroneous communication.

  Therefore, the automatic toll collection system 10 according to the above embodiment interrupts the erroneous communication established between the roadside device installed in the predetermined lane and the vehicle-mounted device existing in the adjacent lane, and makes an error for the vehicle-mounted device. Billing can be prevented.

(Other embodiments)
In the above embodiment, the case where the automatic fee collection system 10 has the configuration shown in FIG. 1 has been described. However, the configuration of the automatic fee collection system 10 is not limited to FIG. FIG. 14 is a schematic diagram illustrating another example of the configuration of the automatic fee collection system 10 and the ETC in-vehicle device 20 mounted on the vehicle V.

  The automatic toll collection system 10 shown in FIG. 14 includes a first gantry 11, roadside devices 12-1, 12-2, vehicle detectors 13-1, 13-2 to 15-1, 15-2, and a signal processing unit 16. The second gantry 112 and the radio wave emission source detection sensor 113 are provided.

  The first gantry 11 is installed across the ETC lanes 1 and 2. Roadside devices 12-1 and 12-2 are attached to the first gantry 11. The roadside devices 12-1 and 12-2 are attached almost directly above the ETC lanes 1 and 2, respectively. In this embodiment, the roadside units 12-1 and 12-2 are installed at a position of, for example, 5 m from the ground.

  The second gantry 112 is installed across the lane so that the radio wave emission source detection sensor 113 is positioned at the center position of the vehicle detectors 14 and 15 and substantially above the island. In the present embodiment, the radio wave emission source detection sensor 113 is installed, for example, at a position 6 m from the ground.

  The functional configuration of the radio wave emission source detection sensor 113 is the same as that of the radio wave emission source detection sensor 17 of FIG. 2, and includes an antenna unit, a reception unit, and a determination processing unit.

  The antenna unit includes, for example, a plurality of antenna elements arranged vertically and horizontally. The radio wave emission source detection sensor 113 forms a second reception beam by the plurality of antenna elements. In the example of FIG. 14, the beam width in the elevation angle direction is set to be, for example, ± 22 degrees by narrowing the beam of the antenna element arranged in the vertical direction. Further, the beam width in the azimuth direction is set to be, for example, ± 90 degrees by setting the lateral distance between the antenna elements to 0.5λ, for example. FIG. 15 is a diagram illustrating an example when the second reception beam formed by the radio wave emission source detection sensor 113 is viewed from the front of the lane.

  As a result, a range of 4 m from the position immediately below the radio wave emission source detection sensor 113 toward the entrance of the ETC lanes 1 and 2 becomes the second reception area. FIG. 16 is a schematic diagram illustrating an example of a second reception area of the radio wave emission source detection sensor 113.

  The functional configuration of the determination processing unit is the same as that of the determination processing unit 173 of FIG. 4, and includes a detection unit, a direction specifying unit, and an erroneous communication determination unit.

  The erroneous communication determination unit determines whether the response signal received by the antenna unit is a signal from one of the ETC lanes 1 and 2 using the arrival direction information. For example, as shown in FIG. 14 and FIG. 15, it is assumed that a signal with an elevation angle of ± 22 degrees or less and an azimuth angle of 9.9 to 37.8 degrees is a signal from ETC lane 1, and the elevation angle is within ± 22 degrees or less. It is assumed that a signal of −9.9 degrees to −37.8 degrees is a signal from ETC lane 2.

  The erroneous communication determination unit determines whether or not the radio wave intensity of the response signal received by the antenna unit exceeds a preset threshold value using the radio wave intensity information. The erroneous communication determination unit determines whether the response signal corresponds to the reception frequency of the roadside devices 12-1 and 12-2 using the frequency information. The erroneous communication determination unit determines whether the communication with the ETC on-vehicle device 20 is an error using these determination results.

  In this way, by installing the radio wave emission source detection sensor 113 at the center position of the vehicle detectors 14 and 15 and almost directly above the island, a large vehicle such as a truck where the ETC on-board unit is installed at a high position can be obtained. Even when passing, it is possible to accurately receive the response signal from the ETC on-vehicle device.

  Moreover, although the said embodiment demonstrated the example which identifies the arrival direction of the electromagnetic wave in an azimuth angle direction by the direction specific | specification part 1732, this embodiment is not necessarily limited to this. For example, the direction specifying unit 1732 may specify the arrival direction of radio waves in the elevation direction in addition to the azimuth direction. Thereby, the radio wave emission source detection sensor 17 can also grasp the position of the vehicle in the elevation angle direction. At this time, the radio wave emission source detection sensor 17 may output position information of the response signal to the roadside units 12-1 and 12-2 in addition to the erroneous communication notification. The roadside devices 12-1 and 12-2 can cope with a case where two or more vehicles exist in the own lane by acquiring the position information of the response signal.

  Note that when the erroneous communication determination process is performed using only the azimuth, it is possible to simplify the antenna unit and the reception unit, compared to the case where the erroneous communication determination process is performed using the azimuth angle and the elevation angle. In addition, when performing miscommunication determination processing using only the azimuth, the processing time required to specify the arrival direction of the response signal is shorter than when performing miscommunication determination processing using the azimuth and elevation angles. There is.

  Moreover, in the said embodiment, the radio wave emission source detection sensor 17 synchronizes with the roadside devices 12-1 and 12-2. The radio wave emission source detection sensor 17 utilizes this fact, and explained an example in which one necessary signal is detected from the received response signal and erroneous communication determination processing is performed on the detected necessary signal. However, the present invention is not limited to this. For example, the radio wave emission source detection sensor 17 may not be synchronized with the roadside devices 12-1 and 12-2. At this time, the radio wave emission source detection sensor 17 detects all signals included in the response signal, and performs an erroneous communication process for each signal. The radio wave emission source detection sensor 17 outputs an erroneous communication notification for each signal to the roadside units 12-1 and 12-2. And the roadside device 12 determines whether communication with the ETC onboard equipment 20 is "error" based on each miscommunication notification. For example, the roadside device 12-1 may determine that the communication with the ETC on-vehicle device 20 is “error” if it receives at least one erroneous communication notification. As a result, the accuracy is higher than in the case where the erroneous communication determination is performed for only one signal.

  In each of the above embodiments, the example in which the radio wave emission source detection sensor is used in the ETC system conforming to the ARIB STD-T55 standard has been described. However, the present invention is not limited to this. For example, the radio wave emission source detection sensor may be used in a DSRC (Dedicated Short Range Communication) system that conforms to the ARIB STD-T75 standard. In addition to the toll road, the radio wave emission source detection sensor according to the above embodiment may be used, for example, in a parking lot.

  In the above embodiment, the case where the radio wave emission source detection sensor is used in an ETC system such as a toll road has been described as an example. However, the present invention is not limited to this. For example, the automatic fee collection system according to the above embodiment may be used as an entrance gate for an amusement park or the like. In this case, the pedestrian is made to hold a responder corresponding to the ETC on-board device, and the radio wave emission source detection sensor determines whether or not the communication between the roadside device and the responder is an error.

  In the above-described embodiment, an example in which the ACTS signal is detected by the detection unit 1731 has been described. However, the present invention is not limited to this. For example, the detection unit 1731 may detect the ACCC signal or the MDS signal instead of the ACTS signal. The reason that the ACTS signal is detected in the embodiment is that the ACTS signal is the earliest signal among the response signals.

  In the above-described embodiment, the erroneous communication determination unit 1733 determines whether or not there is an erroneous communication with respect to all received response signals. However, the present invention is not limited to this. For example, the direction specifying unit 1732 may output the radio field intensity information, the arrival direction information, and the frequency information to the erroneous communication determination unit 1733 only when the acquired radio field intensity exceeds a threshold value. As a result, the erroneous communication determination unit 1733 determines whether or not there is an erroneous communication only for a response signal whose radio field intensity exceeds the threshold value.

  Although the embodiment has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

DESCRIPTION OF SYMBOLS 10 ... Automatic toll collection system 11, 112 ... Gantry 12-1, 12-2 ... Roadside devices 13-1, 13-2, 14-1, 14-2, 15-1, 15-2 ... Vehicle detector 16 ... Signal processing unit 17 ... Radio wave emission source detection sensor 171 ... Antenna unit 172 ... Receiving unit 173 ... Determination processing unit 1731 ... Detection unit 1732 ... Direction specifying unit 1733 ... Error communication determination unit 174 ... Radome 175 ... Heat sinks 176-1 to 176 -N ... antenna elements 177-1 to 177-n ... frequency converter 178 ... local signal generation board 179 ... signal processing board

Claims (16)

In the radio wave emission source detection sensor that is installed in the first and second lanes and is connected to the first and second roadside units that communicate with the responders carried by the mobile body,
An antenna unit for receiving a response signal from the responder by a reception beam including the first and second lanes;
From the response signal, a detection unit that detects a necessary signal based on the reception frequency of the first or second roadside device,
Based on the detection result, the radio signal intensity of the required signal is measured, the arrival direction of the response signal is specified, and the direction specifying unit that specifies the response frequency of the response signal;
Based on the radio field intensity, the direction of arrival, and the response frequency, the response frequency of the response signal that arrives from the first or second lane and whose radio field intensity exceeds a preset threshold is the first or second An erroneous communication determination unit that outputs an erroneous communication notification that the communication with the responder is in error to the first and second roadside devices when determining that the received frequency is incompatible with the reception frequency of the roadside device; A radio wave emission source detection sensor comprising:   When the erroneous communication determination unit determines that a response signal having a radio wave intensity exceeding the threshold is coming from other than the first and second lanes based on the radio wave intensity, the arrival direction, and the response frequency, 2. The radio wave emission source detection sensor according to claim 1, wherein a communication notification is output to the first and second roadside devices.   2. The radio wave emission source detection according to claim 1, wherein, when the radio wave intensity exceeds the threshold, the direction specifying unit outputs the radio wave intensity, the arrival direction, and the response frequency to the erroneous communication determination unit. Sensor.   The radio wave emission source detection sensor according to claim 1, wherein the direction specifying unit specifies the arrival direction based on an azimuth angle.   The radio wave emission source detection sensor according to claim 1, wherein the direction specifying unit specifies the arrival direction based on an azimuth angle and an elevation angle. The response signal includes a plurality of radio signals,
The detection unit is synchronized with the first and second roadside devices, and the plurality of radio waves included in the response signal received by the antenna unit based on the reception frequency of the first or second roadside device The radio wave emission source detection sensor according to claim 1, wherein any one of the signals is detected as the necessary signal. The response signal includes a plurality of radio signals,
The radio wave emission source detection sensor according to claim 1, wherein the detection unit detects all of the plurality of radio wave signals included in the response signal as the necessary signals. In the automatic toll collection system having the first and second roadside devices that are installed in the first and second lanes and communicate with the vehicle-mounted device mounted on the vehicle,
The reception beam comprising said first and second lane, and an antenna unit for receiving a response signal from the response unit,
From the response signal, a detection unit that detects a necessary signal based on the reception frequency of the first or second roadside device,
Based on the detection result, the radio signal intensity of the required signal is measured, the arrival direction of the response signal is specified, and the direction specifying unit that specifies the response frequency of the response signal;
Based on the radio field intensity, the direction of arrival, and the response frequency, the response frequency of the response signal that arrives from the first or second lane and exceeds the preset threshold is the first or second roadside. A miscommunication determination unit that outputs a miscommunication notification that the communication with the responder is in error to the first and second roadside devices. Equipped with a radio wave emission source detection sensor
The automatic toll collection system, wherein the first and second roadside devices interrupt communication with the vehicle-mounted device when receiving the erroneous communication notification.   When the erroneous communication determination unit determines that a response signal having a radio wave intensity exceeding the threshold is coming from other than the first and second lanes based on the radio wave intensity, the arrival direction, and the response frequency, 9. The automatic toll collection system according to claim 8, wherein a communication notification is output to the first and second roadside devices.   9. The automatic toll collection system according to claim 8, wherein, when the radio field intensity exceeds the threshold, the direction specifying unit outputs the radio field intensity, the arrival direction, and the response frequency to the erroneous communication determination unit. .   The automatic fee collection system according to claim 8, wherein the direction specifying unit specifies the arrival direction based on an azimuth angle.   9. The automatic toll collection system according to claim 8, wherein the direction specifying unit specifies the direction of arrival by an azimuth angle and an elevation angle. The response signal includes a plurality of radio signals,
The detection unit is synchronized with the first and second roadside devices, and the plurality of radio waves included in the response signal received by the antenna unit based on the reception frequency of the first or second roadside device 9. The automatic toll collection system according to claim 8, wherein any one of the signals is detected as the necessary signal. The response signal includes a plurality of radio signals,
The detector detects all of the plurality of radio signals included in the response signal as the necessary signals,
The erroneous communication determination unit performs erroneous communication determination for each necessary signal, creates an erroneous communication notification for each necessary signal,
9. The automatic toll collection system according to claim 8, wherein the first and second roadside devices interrupt communication with the vehicle-mounted device with reference to the plurality of erroneous communication notifications.   The radio wave emission source detection sensor is installed between the first and second roadside devices in the same gantry as the first and second roadside devices, and enters the entrances of the first and second lanes from directly below. 9. The automatic toll collection system according to claim 8, wherein the reception beam is formed by tilting in a direction by a preset angle.   The radio wave emission source detection sensor is installed at a position closer to the entrance direction of the first and second lanes than the first and second roadside devices, and forms the reception beam directly below. The automatic fee collection system according to claim 8.

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