JP5734159B2 - ETC communication area multipoint simultaneous measurement device - Google Patents

Description

  The present invention relates to a measuring apparatus. The present invention particularly relates to an ETC (registered trademark) (Electronic, Toll, Collection) communication area multipoint simultaneous measurement apparatus.

  Conventionally, as a measuring device used to measure the electric field strength distribution of an ETC / DSRC (Dedicated Short Range Communication) roadside wireless device (also referred to as a “roadside device”), an electric field strength measuring instrument is used. There are two types: a “trolley type” (see, for example, Patent Document 1) mounted on a truck, and an “in-vehicle type” (for example, refer to Patent Documents 2 and 3) in which a field strength measuring instrument is mounted on a vehicle. When measuring the electric field strength distribution of the roadside wireless device in the operational state, the bogie type measuring device cannot perform the measurement unless road traffic is regulated. On the other hand, in-vehicle type measuring devices can perform measurements without restricting road traffic.

Japanese Patent Laid-Open No. 10-96786 JP 2009-164876 A JP 2011-2288 A

  In a conventional in-vehicle type measuring apparatus, the mounting position of the antenna is a carrier installed at the top of the vehicle or a dashboard inside the vehicle. For this reason, there is a problem that it is difficult to measure an accurate value due to a large influence of radio wave reflection by a vehicle body (such as a bonnet) and attenuation by a vehicle windshield.

  In addition, in the ETC standard, the communication area in which the roadside device and the vehicle-mounted device communicate with each other is defined by a height of 1 meter above the ground, so it is necessary to perform measurement by installing an antenna at a height of 1 meter above the ground. However, when the antenna is attached to the carrier, it is difficult to set the height to 1 meter, and when the antenna is attached to the dashboard, it depends on the height of the vehicle, so it is difficult to adjust the height. There was a problem.

  Also, at the ETC toll booth, the roadside radio device usually radiates radio waves from the moment when the front end of the vehicle enters the communication area, and the roadside radio device stops radio waves at the moment the front end of the vehicle leaves the communication area. For this reason, if the antenna is attached to a carrier or dashboard, radio waves received behind the front end of the vehicle are subject to measurement, and there is a problem that the electric field strength in the communication area cannot be measured accurately. .

  An object of the present invention is, for example, to accurately measure the electric field strength in an ETC communication area.

An ETC communication area multipoint simultaneous measurement apparatus according to one aspect of the present invention is provided.
At the front end of the vehicle traveling direction between the front end of the front bumper of the vehicle and the position about 0.5 m behind the boundary between the front bumper and the body of the vehicle, at a position of about 1 meter from the lower end of the vehicle, A plurality of antennas installed side by side in the width direction of the vehicle, and a vehicle detector installed at a first point on the road starts to transmit radio waves at a first time point when detecting a front end portion in the traveling direction of the vehicle. A roadside for ETC (Electronic Toll Collection) communication that stops transmission of the radio wave at a second time point when another vehicle detector installed at a second point on the side road detects the tip of the vehicle in the traveling direction. A plurality of antennas each receiving the radio wave from a wireless device;
A detection unit that detects positions of the vehicle at a plurality of time points between the first time point and the second time point, and outputs the detection data as detection data;
A measurement unit that measures radio waves received by the plurality of antennas at the plurality of times and outputs the measurement data;
A storage unit for storing the detection data output from the detection unit and the measurement data output from the measurement unit in association with each other;

  According to one aspect of the present invention, the ETC communication area multipoint simultaneous measurement apparatus can accurately measure the electric field strength in the ETC communication area by including a plurality of antennas at the front end in the traveling direction of the vehicle. It becomes possible.

The figure which shows the structure of the measuring apparatus which concerns on Embodiment 1 mounted in the vehicle. FIG. 3 shows an example of how to attach a receiving antenna to a vehicle in the first embodiment. The figure which compared the electromagnetic wave received by Embodiment 1 and the antenna in the past. FIG. 3 shows a relationship between a communication area and a measurement area in the first embodiment. The figure which shows the relationship between the communication area in the past, and a measurement area. 5 is a flowchart showing an example of the operation of the measuring apparatus according to the first embodiment. FIG. 6 shows an example of measurement results of electric field strength in Embodiment 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a measurement apparatus 20 according to the present embodiment that is mounted on a vehicle 10. FIG. 2 is a diagram illustrating an example of attachment of the receiving antenna 21 to the vehicle 10.

  In FIG. 1, a vehicle 10 is equipped with an electronic control unit 11, a measuring device 20, and the like.

  The electronic control unit 11 is mounted inside the vehicle 10. For example, the electronic control unit 11 detects the rotation of the wheel, generates a vehicle speed pulse corresponding to the rotation of the wheel, and inputs it to the processing device 22.

  The measuring device 20 includes a receiving antenna 21, a processing device 22, an operation PC 23 (personal computer), and an operation controller 24. The operating PC 23 may be installed outside the vehicle 10.

  The receiving antenna 21 is an example of an antenna, and at least one receiving antenna 21 is installed at the distal end portion 12 in the traveling direction of the vehicle 10. The receiving antenna 21 receives a radio wave transmitted from a roadside apparatus for ETC communication.

  In the present embodiment, the front end portion 12 of the vehicle 10 refers to a portion between the front end of the front bumper 13 of the vehicle 10 and a position behind D meters from the boundary between the front bumper 13 and the body 14 of the vehicle 10. D is about 0.5 (50 centimeters) at the longest, desirably about 0.3 (30 centimeters), more desirably about 0.2 (20 centimeters).

  In the present embodiment, a plurality of receiving antennas 21 are installed at the front end portion 12 of the vehicle 10 side by side in the width direction of the vehicle 10. This makes it possible to perform multipoint simultaneous measurement of radio waves in the communication area.

  In the example of FIG. 2, five receiving antennas 21 are attached to the front end portion 12 of the vehicle 10 so as to be arranged at equal intervals in the width direction of the vehicle 10. Each receiving antenna 21 has a width W centimeters and a length L centimeters, and is installed at a position H meters from the lower end of the vehicle 10 (that is, the ground height). H is preferably about 1 (meter). W is, for example, 9 (centimeter), and L is, for example, 15 (centimeter). In this case, assuming that the receiving antenna 21 is attached with an inclination of 15 degrees from the horizontal direction, the position of the rear end of the receiving antenna 21 in the traveling direction of the vehicle 10 is approximately 14.5 cm from the position of the front end of the receiving antenna 21. (= 15 · cos 15 °) It will come back. Here, the depth (thickness) of the receiving antenna 21 is not considered.

  The positions of the front end and the rear end of the receiving antenna 21 may be appropriately adjusted according to the shape of the front bumper 13 and the body 14 of the vehicle 10. For example, the receiving antenna 21 may be attached between the front end of the front bumper 13 and the front end of the bonnet (that is, the front end of the body 14). In this case, the rear end of the receiving antenna 21 comes forward from the bonnet. . Alternatively, for example, the receiving antenna 21 may be attached to the bonnet at the very end of the bonnet. In this case, the front end of the receiving antenna 21 is about 14.5 cm from the bonnet front, and the rear end of the receiving antenna 21 is about 14.5 cm from the bonnet front. You will come to a position behind the meter. Alternatively, for example, the receiving antenna 21 may be attached to the inside of the bonnet, and in this case, the front end of the receiving antenna 21 comes behind the front end of the bonnet. When the receiving antenna 21 is attached to the inside of the hood, it is necessary to replace the hood with a material that can easily transmit radio waves. Further, when the receiving antenna 21 is attached between the front end of the front bumper 13 and the bonnet tip or on the bonnet, the receiving antenna 21 may be covered with a protective cover made of a material that easily allows radio waves to pass through.

  Each receiving antenna 21 is connected to the processing device 22 via a cable 28. Of the five receiving antennas 21, the two receiving antennas 21 on the right side from the center toward the traveling direction of the vehicle 10 have a cable 28 connected to the left side surface thereof. The two receiving antennas 21 on the left side from the center toward the traveling direction of the vehicle 10 are connected to a cable 28 on the right side. The central receiving antenna 21 has a cable 28 connected to the left side, but the cable 28 may be connected to the right side. Cables 28 extending from the respective receiving antennas 21 are drawn into the inside of the body 14 through holes formed in the body 14 (for example, a bonnet) of the vehicle 10, bundled and connected to the processing device 22.

  Thus, in the present embodiment, the plurality of receiving antennas 21 are installed so as to be as symmetric as possible. That is, the one receiving antenna 21 and the receiving antenna 21 on the right side of the one receiving antenna 21 are connected to the cable 28 from the left direction, and the receiving antenna 21 on the left side of the one receiving antenna 21 is The cable 28 is connected from the right direction. This makes it easier to bundle the cables 28 inside the body 14. Further, since the cable 28 does not protrude outward in the width direction of the vehicle 10, the receiving antenna 21 can be installed to both left and right ends of the vehicle 10, and the measurement range in the width direction of the vehicle 10 can be widened. Such an effect becomes remarkable particularly when the cable 28 (coaxial cable or the like) made of a material that is difficult to bend is used.

  Each receiving antenna 21 receives a radio wave transmitted from a roadside apparatus installed at an ETC toll gate.

  The processing device 22 is mounted inside the vehicle 10 and includes a detection unit 25, a measurement unit 26, and a storage unit 27.

  The detection unit 25 detects the position of the vehicle 10 at a predetermined time and outputs it as detection data. In the present embodiment, the detection unit 25 detects the position of the vehicle 10 by counting vehicle speed pulses input from the electronic control unit 11. The detection unit 25 detects the position of the vehicle 10 using a GPS (Global Positioning System) or a quasi-zenith satellite system, or detects the position of the vehicle 10 using other methods. Also good.

  The measuring unit 26 measures the radio waves received by the respective receiving antennas 21 at the predetermined time point and outputs it as measurement data. In the present embodiment, the measurement unit 26 measures the electric field strength of the radio wave received by each receiving antenna 21 at the predetermined time point, and outputs the digital data of the measurement value as measurement data. Note that the measurement unit 26 may output analog data of radio waves received by the receiving antennas 21 at the predetermined time point as measurement data.

  The storage unit 27 is a memory, a tape, or the like, and stores the detection data output from the detection unit 25 and the measurement data output from the measurement unit 26 in association with each other. In addition, the memory | storage part 27 may be installed in the state which can be attached or detached. When the measurement unit 26 outputs analog data as measurement data, the output analog data may be recorded on a magnetic tape in the storage unit 27, for example.

  Note that any one or a part of the detection unit 25, the measurement unit 26, and the storage unit 27 may be mounted on the operation PC 23 instead of the processing device 22.

  The operation PC 23 is an example of an analysis unit, and is mounted inside the vehicle 10 in the example shown in FIG. The operation PC 23 analyzes the characteristics of the radio wave for each position of the vehicle 10 from the detection data and measurement data stored in the storage unit 27 of the processing device 22 and outputs the result as a graph or the like on a screen or the like. In the present embodiment, the operation PC 23 graphs the relationship between the position of the vehicle 10 and the electric field strength and displays the graph.

  As described above, the operation PC 23 may be installed outside the vehicle 10. When installing the operation PC 23 outside the vehicle 10, the storage unit 27 is detached from the vehicle 10 and used. For example, the removed storage unit 27 is connected to the operation PC 23 installed outside the vehicle 10, and the characteristics of the radio wave at each position of the vehicle 10 are analyzed from the detection data and measurement data stored in the storage unit 27. And output to a screen or the like as a graph or the like. Alternatively, when the operation PC 23 is installed outside the vehicle 10, a communication unit (not shown) is provided in the vehicle 10 as a part of the processing device 22. For example, the detection data and measurement data stored in the storage unit 27 are transmitted to the operation PC 23 installed outside the vehicle 10 via the communication unit having a wireless communication function, and the transmitted detection data and measurement data are transmitted. From the above, the characteristics of the radio wave for each position of the vehicle 10 are analyzed and output as a graph or the like on a screen or the like.

  Although not shown, the processing device 22 and the operation PC 23 include a CPU (Central Processing Unit) that executes a program. The CPU controls ROM (Read / Only / Memory), RAM (Random / Access / Memory), and other hardware devices. In the description of the present embodiment, what is described as “to part” may be “to circuit”, “to device”, “to device”, and “to step”, “to process”, “to”. ~ Procedure "," ~ process ". That is, what is described as “˜unit” may be realized by firmware stored in the ROM. Alternatively, what is described as “˜unit” may be realized only by software, or only by hardware such as an element, a device, a board, and wiring. Alternatively, what is described as “to part” may be realized by a combination of software and hardware, or a combination of software, hardware and firmware. Firmware and software are stored in the recording medium as programs. The program is read by the CPU and executed by the CPU. That is, the program causes the computer to function as “to part” described in the description of the present embodiment. Or a program makes a computer perform the procedure and method of "-part" described by description of this Embodiment.

  The operation controller 24 is an example of an operation unit and is mounted inside the vehicle 10. The operation controller 24 receives a measurement start operation, a measurement end operation, and a marking operation. The operation controller 24 includes, for example, a button for accepting each operation. Details of each operation will be described later.

  As described above, in the present embodiment, the measuring device 20 receives radio waves transmitted from the roadside radio device for ETC communication using the plurality of receiving antennas 21, and each reception is performed using the processing device 22. The electric field strength of the radio wave received by the antenna 21 is measured. That is, the measuring device 20 functions as an ETC communication area multipoint simultaneous measuring device. Note that the measurement apparatus 20 may use a DSRC system other than the ETC as a measurement target, or may use a system that employs another wireless communication method as a measurement target.

  FIG. 3 is a diagram comparing radio waves received by an antenna in the present embodiment and in the prior art.

  As shown in FIG. 3, conventionally, when an antenna is attached to a carrier or a dashboard, it has been easily affected by radio wave reflection from the vehicle body. On the other hand, in the present embodiment, since the receiving antenna 21 is attached to the distal end portion 12 of the vehicle 10, the vehicle body is positioned behind the receiving antenna 21, and is not easily affected by radio wave reflection from the vehicle body. . Therefore, according to the present embodiment, it is possible to accurately measure the electric field strength of radio waves from the ETC / DSRC roadside wireless device 30 (roadside wireless device for ETC communication) installed at an ETC toll booth.

  Conventionally, when an antenna is attached to a carrier, the height of the antenna cannot be adjusted to 1 meter. Further, when the antenna is attached to the dashboard, it is difficult to adjust the antenna attachment height to 1 meter because the antenna attachment height is determined depending on the vehicle type or the like. On the other hand, in the present embodiment, since the receiving antenna 21 is attached to the distal end portion 12 of the vehicle 10, the mounting height of the receiving antenna 21 can be easily adjusted to 1 meter. Therefore, according to the present embodiment, it is possible to accurately measure the electric field strength of 1 meter above the ground defined by the ETC standard.

  FIG. 4 is a diagram showing the relationship between the communication area and the measurement area in the present embodiment. FIG. 5 is a diagram illustrating a relationship between a communication area and a measurement area in the related art.

  At an ETC toll gate, a vehicle detector 31a is installed at the start point (first point on the road) of the communication area, and another vehicle detector 31b is installed at the end point (second point on the road) of the communication area. The vehicle detectors 31a and 31b both detect the front end portion 12 (for example, a bumper) of the vehicle 10. The ETC / DSRC roadside apparatus 30 starts transmission (radiation) of radio waves at a first time point when the vehicle detector 31a detects the front end portion 12 of the vehicle 10, that is, at a timing when the front end of the vehicle 10 enters the communication area. . And the ETC / DSRC roadside radio | wireless apparatus 30 stops transmission of an electromagnetic wave at the 2nd time point which the vehicle detector 31b detects the front-end | tip part 12 of the vehicle 10, ie, the timing which the front-end | tip of the vehicle 10 comes out of a communication area.

  As shown in FIG. 5, conventionally, when an antenna is attached to a carrier, radio waves received behind the front end of the vehicle 10 are to be measured, so the electric field strength in the communication area cannot be measured accurately. It was. For example, the radio wave stops from the moment when the tip of the vehicle 10 leaves the communication area, but at this time, the antenna has not reached the end point of the communication area, and thus there is a region where the electric field strength cannot be measured in a part of the communication area. End up. Further, since the communication area and the measurement area are shifted, it is necessary to correct the position of the vehicle 10 when associating the position of the vehicle 10 with the measurement result of the electric field strength. These problems also occur when the antenna is attached to the dashboard.

  On the other hand, as shown in FIG. 4, in this embodiment, the receiving antenna 21 is attached to the front end portion 12 of the vehicle 10, so that the electric field strength in the communication area can be accurately measured. For example, the radio wave stops from the moment when the tip of the vehicle 10 leaves the communication area. At this point, the receiving antenna 21 reaches the end point of the communication area, so that the electric field strength in the entire communication area can be measured. . Further, since the communication area and the measurement area coincide with each other, the position of the vehicle 10 and the measurement result of the electric field strength can be easily associated with each other.

  Below, operation | movement of the measuring apparatus 20 is demonstrated.

  FIG. 6 is a flowchart illustrating an example of the operation of the measurement apparatus 20. FIG. 7 is a diagram illustrating an example of the measurement result of the electric field strength in the present embodiment.

  In step S <b> 11 of FIG. 6, when the operation controller 24 receives a measurement start operation (for example, performed by pressing a button) by the user, the operation controller 24 inputs a signal instructing the start of measurement to the processing device 22. The user may perform the measurement start operation at an arbitrary timing, but here, the vehicle 10 performs the measurement start operation while traveling in front of the vehicle detector 31a (for example, at a position about 5 meters before). To do.

  In step S <b> 12 of FIG. 6, when a signal instructing the start of measurement is input from the operation controller 24, the processing device 22 starts counting vehicle speed pulses by the detection unit 25 and measuring electric field strength by the measurement unit 26. To do. Thereafter, the detection unit 25 counts the number of vehicle speed pulses input from the electronic control unit 11 at regular intervals, and in real time as count data (for example, every time a vehicle speed pulse is input from the electronic control unit 11). Output. For each reception antenna 21, the measurement unit 26 converts the electric field strength of the radio wave of the ETC / DSRC roadside wireless device 30 received by the reception antenna 21 into a digital value, and outputs it as measurement data in real time. Each time the count data is output from the detection unit 25, the storage unit 27 outputs the count data, the corresponding time, and the measurement data for each reception antenna 21 output from the measurement unit 26 (the reception antenna 21 at the same time). (Measured value of the electric field strength of the received radio wave).

  As shown in FIG. 7, before the front end 12 of the vehicle 10 passes through the vehicle detector 31a, no radio wave is radiated from the ETC / DSRC roadside radio device 30, and the receiving antenna 21 receives only noise. A value close to 0 is recorded as measurement data. When the front end 12 of the vehicle 10 passes the vehicle detector 31a, radio waves are radiated from the ETC / DSRC roadside radio device 30 and the reception antenna 21 receives the radio waves. A value (unit: dBm) is recorded as measurement data. At this time, a ripple may occur in the measured value due to the influence of the reflected wave from the road surface or the like. Further, when the receiving antenna 21 moves in the vicinity immediately below the ETC / DSRC roadside apparatus 30, the measurement value once reduced due to the side lobe of the beam radiated from the ETC / DSRC roadside apparatus 30 increases again. Become.

  In step S <b> 13 of FIG. 6, when the operation controller 24 receives a marking operation (for example, performed by pressing a button) by a user, the operation controller 24 inputs a signal instructing marking to the processing device 22. The user performs a marking operation when the vehicle 10 passes the position of the vehicle detector 31b (that is, the end point of the communication area).

  In step S <b> 14 of FIG. 6, when a signal instructing marking is input from the operation controller 24, the processing device 22 records mark information in the storage unit 27. At this time, the memory | storage part 27 memorize | stores the time stamp (Time data and the identification signal which can be identified as a time stamp) which shows the time when the vehicle 10 passed the position of the vehicle detector 31b as mark information.

  As shown in FIG. 7, after the front end 12 of the vehicle 10 passes the vehicle detector 31b, no radio wave is radiated from the ETC / DSRC roadside radio device 30, and the receiving antenna 21 receives only noise. A value close to 0 is recorded as measurement data.

  In step S15 of FIG. 6, when the operation controller 24 receives a measurement end operation (for example, performed by pressing a button) by the user, the operation controller 24 inputs a signal instructing the end of the measurement to the processing device 22. The user may perform the measurement end operation at an arbitrary timing. Here, the user performs the measurement end operation while the vehicle 10 travels beyond the vehicle detector 31b (for example, at a position about 10 meters ahead). To do.

  In step S <b> 16 of FIG. 6, when a signal instructing the end of measurement is input from the operation controller 24, the processing device 22 ends counting of vehicle speed pulses by the detection unit 25 and measurement of electric field strength by the measurement unit 26. To do. At this time, the detection unit 25 reads the corresponding time (hereinafter referred to as “measurement time”) from the storage unit 27 for each combination of count data and measurement data stored in the storage unit 27. The detection unit 25 reads count data corresponding to the time indicated by the mark information stored in the storage unit 27 (hereinafter referred to as “marking time”) from the storage unit 27. For each measurement time, the detector 25 detects the difference between the measurement time and the marking time, the number of vehicle speed pulses indicated by the count data corresponding to the measurement time, and the vehicle speed pulse indicated by the count data corresponding to the marking time. The relative position of the vehicle 10 from the position of the vehicle detector 31b (that is, the end point of the communication area) at the measurement time is calculated from the difference from the number. Then, the detection unit 25 outputs detection data indicating the calculated relative position of the vehicle 10. That is, the detection unit 25 calculates a difference between each measurement time (an example of a predetermined time) and a time when the marking operation is received by the operation controller 24, and based on the calculated difference, the vehicle at each measurement time. As the position of 10, the relative position of the vehicle 10 from the position of the vehicle detector 31b (an example of a predetermined point) is detected. The storage unit 27 stores the detection data output from the detection unit 25 in association with the measurement data corresponding to each measurement time.

  In step S <b> 17 of FIG. 6, the operation PC 23 refers to the detection data and measurement data stored in the storage unit 27 of the processing device 22, and the electric field for each position of the vehicle 10, that is, the position of the reception antenna 21. The received electric field strength distribution in the communication area is analyzed from the measured intensity value. Then, the operation PC 23 displays the analysis result on the screen as a graph as shown in FIG. 7, for example.

  When the operation PC 23 is installed outside the vehicle 10, the storage unit 27 is removed from the vehicle 10 as described above. Thereafter, the removed storage unit 27 is connected to the operation PC 23 installed outside the vehicle 10, and the characteristics of the radio wave for each position of the vehicle 10 are analyzed from the detection data and measurement data stored in the storage unit 27. For example, a graph as shown in FIG. 7 is displayed on the screen. Alternatively, when the operation PC 23 is installed outside the vehicle 10, as described above, the detection data and measurement data stored in the storage unit 27 are transmitted to the outside of the vehicle 10 via the communication unit provided in the vehicle 10. The characteristics of the radio wave for each position of the vehicle 10 are analyzed from the transmitted detection data and measurement data, and a graph as shown in FIG. 7, for example, is displayed on the screen.

  As described above, the measurement device 20 according to the present embodiment can measure the antenna position and structure of the measuring device in the electric field strength distribution measurement of the ETC roadside wireless device using the in-vehicle type measuring device. It is possible to reduce the influence of radio wave reflection by the vehicle and to measure the electric field strength at a more accurate position.

  As described above, conventionally, in an electric field strength measuring apparatus using an in-vehicle type measuring device, a method of installing a measurement antenna on a dashboard in a vehicle or on a carrier attached to a vehicle ceiling has been adopted. However, with such a method, it is difficult to accurately measure the electric field strength due to disturbances such as the influence of reflected waves on the vehicle ceiling and bonnet and the attenuation of radio waves by the windshield. In addition, it is difficult to perform measurement at a desired height (1 meter above the ground) due to the antenna installation position. Furthermore, at the ETC toll booth, radio waves are radiated from the moment when the vehicle tip enters the communication area, but since the receiving antenna is not attached to the vehicle tip, the electric field strength in the communication area cannot be measured accurately. It was.

  On the other hand, in the present embodiment, by installing the measurement antenna near the bumper at the front end of the vehicle, the vehicle body is behind the antenna, so that the influence of the reflected wave by the vehicle body can be reduced. Further, since the antenna is attached to the front end of the vehicle, the electric field strength in the communication area of the ETC toll gate can be accurately measured, and the installation height can be adjusted to a desired height by adjustment at the time of mounting. Moreover, it has a structure that is easy to mount on a vehicle by using two types of wiring for connecting the antenna and the measuring instrument main body in the left-right direction.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, A various change is possible as needed.

  10 vehicle, 11 electronic control unit, 12 tip, 13 front bumper, 14 body, 20 measuring device, 21 receiving antenna, 22 processing device, 23 operating PC, 24 operating controller, 25 detecting unit, 26 measuring unit, 27 Storage unit, 28 cables, 30 ETC / DSRC roadside wireless device, 31a, 31b Vehicle detector.

Claims (4)

At the front end of the vehicle traveling direction between the front end of the front bumper of the vehicle and the position about 0.5 m behind the boundary between the front bumper and the body of the vehicle, at a position of about 1 meter from the lower end of the vehicle, A plurality of antennas installed side by side in the width direction of the vehicle, and a vehicle detector installed at a first point on the road starts to transmit radio waves at a first time point when detecting a front end portion in the traveling direction of the vehicle. A roadside for ETC (Electronic Toll Collection) communication that stops transmission of the radio wave at a second time point when another vehicle detector installed at a second point on the side road detects the tip of the vehicle in the traveling direction. A plurality of antennas each receiving the radio wave from a wireless device;
A detection unit that detects positions of the vehicle at a plurality of time points between the first time point and the second time point, and outputs the detection data as detection data;
A measurement unit that measures radio waves received by the plurality of antennas at the plurality of times and outputs the measurement data;
An ETC communication area multipoint simultaneous measurement apparatus comprising: a storage unit that stores detection data output from the detection unit and measurement data output from the measurement unit in association with each other. The ETC communication area multipoint simultaneous measurement device further includes:
An operation unit that receives an operation performed when the vehicle passes a predetermined point;
The detection unit calculates a difference between the plurality of time points and a time point when the operation is accepted by the operation unit, and based on the calculated difference, the position of the vehicle at the plurality of time points is determined from the predetermined point. 2. The ETC communication area multipoint simultaneous measurement apparatus according to claim 1, wherein a relative position of the vehicle is detected. The plurality of antennas are connected to the measurement unit via cables, respectively.
Of the plurality of antennas, one antenna and an antenna on the right side from the one antenna toward the traveling direction of the vehicle are connected to the cable from the left direction, and from the one antenna toward the traveling direction of the vehicle. 3. The ETC communication area simultaneous multipoint measurement apparatus according to claim 1, wherein the left antenna is connected to the cable from the right direction.   4. The ETC communication area according to claim 1, wherein the measurement unit outputs, as the measurement data, data indicating electric field strengths of radio waves received by the plurality of antennas at the plurality of time points. 5. Multi-point simultaneous measurement device.

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