JP2019149189A - Vehicle detector and vehicle detection system - Google Patents

Abstract

To provide a vehicle detector and a vehicle detection system capable of easily grasping detailed traffic situations without being largely affected by ambient environment.SOLUTION: A vehicle detector 11 comprises: an antenna 31 which receives radio waves to be transmitted from other devices; and a vehicle information creation part 33 which measures the radio waves to be received by the antenna to create vehicle information regarding a vehicle on the basis of variation of measurement results. The antenna is embedded under a road surface through which the vehicle passes or under a road surface on which the vehicle stops, or installed on the road surface through which the vehicle passes or the road surface on which the vehicle stops. The vehicle information creation part creates vehicle information on the basis of a measured reception level and measurement time.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vehicle detector and a vehicle detection system, and more particularly to a vehicle detector and a vehicle detection system using radio waves.

  In order to grasp the traffic situation on the road, traffic volume and speed are measured by a vehicle sensing device.

  Conventionally, vehicle sensing devices such as a loop type and a camera type have been used. The loop type vehicle sensing device senses passage of a vehicle or the like using a change in inductance of a loop coil embedded under the road surface. The camera-type vehicle sensing device senses the presence of a vehicle traveling on a road by processing an image captured using a camera.

  However, the loop-type vehicle sensing device has a problem that it is difficult to perform installation, and a failure due to cable disconnection is likely to occur even after installation. In addition, camera-type vehicle detectors may have low detection accuracy at night or during rainfall.

  On the other hand, a radio wave type buried vehicle sensing device can be installed relatively easily and is less affected by weather and day and night. As a radio wave type buried vehicle sensing system, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2004-21301) discloses the following vehicle sensing system. That is, the vehicle sensing system is disposed so as to be able to receive the radiated radio wave and the radio wave radiating means for radiating the radio wave upward from an antenna provided on a road on which the vehicle runs, and facing the travel location of the vehicle. A radio wave receiving means for detecting the presence or absence of a vehicle based on the presence or absence of a received radio wave, and a traffic flow determination means for determining a traffic flow including the number of passing vehicles and traffic congestion based on the vehicle presence / absence detection result. Prepare.

  Patent Document 2 (Japanese Patent Laid-Open No. 2-48799) discloses the following vehicle detector. That is, the vehicle detector is embedded under the road surface through which the vehicle passes, and a sensor unit that detects the passage of the vehicle, and a signal processing unit that is installed on the ground and receives the radio waves transmitted from the sensor unit and performs signal processing. The sensor unit receives a radio wave transmitted by itself, a modulation unit that modulates according to the intensity of the received radio wave, a transmission unit that transmits the modulated radio wave, and power to each of the units When the vehicle passes over the sensor unit, the radio wave is reflected from the vehicle and the reception level of the receiving means is increased, so that the passage of the vehicle is detected.

JP 2004-21301 A Japanese Patent Laid-Open No. 2-48799

  However, since the vehicle detection system described in Patent Document 1 and the vehicle sensor described in Patent Document 2 cannot detect the vehicle speed or the type of vehicle, it is necessary to grasp more detailed traffic conditions. Insufficient for use.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle sensor and a vehicle detection system capable of easily grasping detailed traffic conditions without being greatly affected by the surrounding environment. Is to provide.

  (1) In order to solve the above-described problem, a vehicle detector according to an aspect of the present invention measures an antenna that receives a radio wave transmitted from another device, and measures the radio wave received by the antenna. A vehicle information creation unit that creates vehicle information related to a vehicle based on a change in result, and the antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or It is installed on the road surface on which the vehicle passes or on the road surface on which the vehicle stops.

  (7) In order to solve the above-described problem, a vehicle detector according to another aspect of the present invention is embedded under a road surface through which the vehicle passes or under a road surface where the vehicle stops, or the vehicle passes through. A measurement antenna that receives a radio wave transmitted from a transmission device including a road surface antenna installed on a road surface or a road surface on which a vehicle stops; and the radio wave received by the measurement antenna is measured, and based on a change in the measurement result A vehicle information creation unit that creates vehicle information related to the vehicle, and the measurement antenna is installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops.

  (9) In order to solve the above-described problem, a vehicle detection system according to an aspect of the present invention includes a reception device and one or more vehicle detectors, and the vehicle detector is a device other than the vehicle detector. An antenna that receives radio waves transmitted from the device, a vehicle information creation unit that measures the radio waves received by the antenna and creates vehicle information related to a vehicle based on a change in measurement results, and the reception of the vehicle information The antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or a road surface through which the vehicle passes or the vehicle stops. Installed on the road surface, the receiving device creates comprehensive vehicle information based on the vehicle information received from each of the vehicle detectors.

  (11) In order to solve the above-described problem, a vehicle sensing system according to another aspect of the present invention is embedded under a road surface through which the vehicle passes or under a road surface where the vehicle stops, or the vehicle passes through. A transmission device including a road surface antenna installed on a road surface or a road surface on which the vehicle stops, and a vehicle detector, the vehicle detector receiving a radio wave transmitted from the road surface antenna; A vehicle information creation unit that measures the radio waves received by a measurement antenna and creates vehicle information related to the vehicle based on a change in measurement results, the measurement antenna being located above a road surface through which the vehicle passes or It is installed above the road surface where the vehicle stops.

  (14) In order to solve the above-described problem, a vehicle detector according to another aspect of the present invention includes a monitoring unit that monitors a change in a magnetic field, and a change in the magnetic field is predetermined based on a monitoring result of the monitoring unit. An acquisition unit that acquires timing satisfying a condition and a speed calculation unit that calculates the speed of the vehicle based on the timing acquired by the acquisition unit.

  (24) In order to solve the above-described problem, a vehicle detection system according to another aspect of the present invention includes a reception device and one or more vehicle detectors, and the vehicle detector monitors a change in a magnetic field. Based on the monitoring result of the monitoring unit, an acquisition unit that acquires a timing at which the change in the magnetic field satisfies a predetermined condition, and calculates a vehicle speed based on the timing acquired by the acquisition unit A speed calculation unit; and a communication unit that transmits vehicle information indicating the speed calculated by the speed calculation unit to the reception device, wherein the reception device is based on the vehicle information received from each vehicle sensor. To create comprehensive vehicle information.

  The present invention can be realized not only as a vehicle detector including such a characteristic processing unit, but also as a method using such characteristic processing as a step, or for causing a computer to execute such a step. Or as a program. Further, it can be realized as a semiconductor integrated circuit that realizes part or all of the vehicle detector.

  According to the present invention, it is possible to easily grasp the detailed traffic situation without being greatly affected by the surrounding environment.

FIG. 1 is a diagram showing a configuration of a vehicle sensing system according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating reception of sensing radio waves by the vehicle detector in the vehicle sensing system according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the first embodiment of the present invention. FIG. 4 is a diagram showing the configuration of the vehicle detector according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating an example of a sequence in which the vehicle sensor according to the first embodiment of the present invention transmits vehicle information to the radio device. FIG. 6 is a diagram showing an example of the relationship between the distance L shown in FIG. 2 and the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the second embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the third embodiment of the present invention. FIG. 8 is a diagram illustrating reception of radio waves for detection by the vehicle detector in the vehicle detection system according to the fourth embodiment of the present invention. FIG. 9 is a diagram illustrating an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the fourth embodiment of the present invention. FIG. 10 shows the relationship between the frequency of the sensing radio wave and the distance L shown in FIG. 2 when the reception level of the sensing radio wave reaches a predetermined value in the vehicle sensing system according to the fifth embodiment of the present invention. FIG. FIG. 11 is a diagram showing an example of the relationship between the distance L shown in FIG. 2 and the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the fifth embodiment of the present invention. FIG. 12 is a diagram illustrating reception of radio waves for detection by the vehicle detector in the vehicle detection system according to the sixth embodiment of the present invention. FIG. 13 is a diagram showing a configuration of a vehicle sensing system according to the seventh embodiment of the present invention. FIG. 14 is a diagram showing a configuration of a vehicle sensing system according to the eighth embodiment of the present invention. FIG. 15 shows an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector and a temporal change in the magnetic field level in the vehicle detector in the vehicle sensing system according to the eighth embodiment of the present invention. FIG. FIG. 16 shows another example of the temporal change in the reception level of the sensing radio wave received by the vehicle detector and the temporal change in the magnetic field level in the vehicle detector in the vehicle sensing system according to the eighth embodiment of the present invention. FIG. FIG. 17 is a diagram showing a configuration of a vehicle sensor according to the eighth embodiment of the present invention. FIG. 18 is a diagram showing magnetic field measurement in the vehicle sensing system according to the ninth embodiment of the present invention. FIG. 19 is a diagram showing the relationship between the distance L shown in FIG. 18 and the magnetic field level in the vehicle detector in the vehicle sensing system according to the ninth embodiment of the present invention. FIG. 20 is a diagram showing the reflection of the velocity detection radio wave radiated by the vehicle detector in the vehicle sensing system according to the tenth embodiment of the present invention. FIG. 21 is a diagram showing a configuration of a vehicle detector according to the tenth embodiment of the present invention. FIG. 22 is a diagram illustrating an example of the arrangement of antennas of the vehicle detector in the vehicle detection system according to the eleventh embodiment of the present invention. FIG. 23 is a diagram showing the configuration of the vehicle detector according to the eleventh embodiment of the present invention. FIG. 24 is a diagram showing another example of the antenna arrangement of the vehicle detector in the vehicle detection system according to the eleventh embodiment of the present invention. FIG. 25 is a diagram showing a configuration of a vehicle sensing system according to the twelfth embodiment of the present invention. FIG. 26 is a diagram showing a configuration of a vehicle sensing system according to the thirteenth embodiment of the present invention. FIG. 27 is a diagram illustrating reception of sensing radio waves by the vehicle detector in the vehicle sensing system according to the thirteenth embodiment of the present invention. FIG. 28 is a diagram illustrating the configuration of the transmission apparatus according to the thirteenth embodiment of the present invention. FIG. 29 is a diagram showing a configuration of a vehicle detector according to the thirteenth embodiment of the present invention. FIG. 30 is a diagram illustrating an example of measurement results of sensing radio waves by the vehicle detector according to the thirteenth embodiment of the present invention. FIG. 31 is a diagram showing another example of the measurement result of the sensing radio wave by the vehicle detector according to the thirteenth embodiment of the present invention. FIG. 32 is a diagram showing an example of a sequence in which the vehicle sensor according to the fourteenth embodiment of the present invention creates vehicle information. FIG. 33 is a diagram showing a configuration of a vehicle sensing system according to the fifteenth embodiment of the present invention. FIG. 34 is a diagram showing measurement of a magnetic field in the vehicle sensing system according to the fifteenth embodiment of the present invention. FIG. 35 is a diagram showing an example of the relationship between the distance L shown in FIG. 34 and the magnetic field level in the vehicle detector in the vehicle sensing system according to the fifteenth embodiment of the present invention. FIG. 36 is a diagram showing the configuration of the vehicle detector according to the fifteenth embodiment of the present invention. FIG. 37 is a diagram illustrating an example of a sequence in which the vehicle detector in the vehicle detection system transmits vehicle information to the reception device. FIG. 38 is a diagram showing a configuration of the vehicle sensing system according to the sixteenth embodiment of the present invention.

  First, the contents of the embodiment of the present invention will be listed and described.

  (1) A vehicle sensor according to an embodiment of the present invention includes an antenna that receives a radio wave transmitted from another device, the radio wave received by the antenna, and a vehicle based on a change in the measurement result. A vehicle information creation unit that creates vehicle information regarding the antenna, and the antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or a road surface through which the vehicle passes or the It is installed on the road surface where the vehicle stops.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. Further, from the change in the value obtained by measuring the radio wave, for example, not only the information on whether or not the vehicle is present above the vehicle detector but also the information on the speed, the vehicle type or the traveling direction of the vehicle. Therefore, it is possible to easily grasp the detailed traffic situation.

  (2) Preferably, the vehicle detector operates using electric power stored in a battery, and the vehicle detector further includes a sleep control unit that intermittently operates the vehicle information creation unit, The sleep control unit restarts the operation of the vehicle information creation unit when the predetermined condition is satisfied after the operation of the vehicle information creation unit is stopped.

  With such a configuration, when the vehicle does not pass over the vehicle detector for a predetermined period of time, the operation of the vehicle information creation unit is stopped, and when the vehicle is about to pass over the vehicle sensor, the vehicle information creation unit Since intermittent operation such as resuming operation can be performed, power consumption of the battery by the vehicle detector can be suppressed, and for example, the frequency of battery replacement can be reduced. In particular, when a vehicle sensor with a built-in battery or a single battery is embedded under the road surface, the maintenance cost of the vehicle sensor such as battery replacement work can be effectively reduced.

  (3) Preferably, the vehicle detector includes a communication unit that transmits the vehicle information to a receiving device, and the communication unit provides a notification that the vehicle information can be received or an instruction to transmit the vehicle information. When the vehicle sensor of its own receives from the receiving device, the vehicle information is transmitted to the receiving device.

  With such a configuration, for example, when a plurality of vehicle detectors are installed for one receiving device, each vehicle detector can transmit vehicle information at a different timing from the other vehicle detectors. The collision of radio waves transmitted from each vehicle sensor can be avoided. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of the vehicle information by a vehicle detector can be reduced, and consumption of electric power can be suppressed. Note that the receiving device may be a device that transmits a radio wave measured by the vehicle sensor, or may be a device other than a device that transmits the radio wave.

  (4) More preferably, the communication unit repeatedly transmits the vehicle information, and when the vehicle detector receives a notification that the reception of the vehicle information is completed from the receiving device, the vehicle Stop sending information.

  With such a configuration, for example, even when the state of the transmission path between the vehicle detector and the receiving device is bad, the vehicle information can be more reliably transmitted to the receiving device.

  (5) Preferably, the radio wave is a radio wave transmitted from a transmitter that transmits radio waves to communicate with a radio other than the vehicle detector.

  With such a configuration, vehicle information can be created using radio waves transmitted by existing equipment. Therefore, compared with the case where a device for transmitting radio waves for vehicle detection is newly installed, the vehicle detector is The introduction cost of the vehicle sensing system including it can be reduced.

  (6) Preferably, the vehicle detector further includes a communication unit that communicates with the other device by transmitting / receiving a signal to / from the other device via the antenna, and the vehicle information creation unit includes the measurement The vehicle information is created based on a change in the result and whether or not the communication unit can receive a signal transmitted from the other device.

  With such a configuration, for example, vehicle information can be created from the measurement result of the radio wave used for the communication in the case where the communication with the other device can be performed satisfactorily, so that the influence of noise and the like is small. More reliable vehicle information can be created using radio waves of good quality.

  (7) The vehicle detector according to the embodiment of the present invention is embedded under the road surface on which the vehicle passes or under the road surface on which the vehicle stops, or on the road surface on which the vehicle passes or on the road surface on which the vehicle stops. A measurement antenna that receives radio waves transmitted from a transmission device including a road surface antenna installed; and measures the radio waves received by the measurement antenna and creates vehicle information related to the vehicle based on changes in measurement results The measurement antenna is installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. Further, from the change in the value obtained by measuring the radio wave, for example, not only the information on whether or not the vehicle is present above the vehicle detector but also the information on the speed, the vehicle type or the traveling direction of the vehicle. Therefore, it is possible to easily grasp the detailed traffic situation.

  (8) Preferably, the vehicle detector further includes a communication unit that communicates with the transmission device by transmitting and receiving signals to and from the transmission device via the measurement antenna, and the vehicle information creation unit includes the measurement result The vehicle information is created on the basis of the change in the signal and whether or not the communication unit can receive the signal transmitted from the transmission device.

  With such a configuration, for example, when it is possible to communicate with the transmission device satisfactorily, vehicle information can be created from the measurement result of the radio wave used for the communication, so there is little influence of noise, More reliable vehicle information can be created using radio waves with good quality.

  (9) A vehicle detection system according to an embodiment of the present invention includes a receiving device and a plurality of vehicle detectors, and the vehicle detector receives radio waves transmitted from devices other than the vehicle detector. An antenna, a vehicle information creation unit that measures the radio wave received by the antenna, creates vehicle information about the vehicle based on a change in the measurement result, and a communication unit that transmits the vehicle information to the receiving device The antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops. Based on the vehicle information received from the vehicle detectors, comprehensive vehicle information is created.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. Further, from the change in the value obtained by measuring the radio wave, for example, not only the information on whether or not the vehicle is present above the vehicle detector but also the information on the speed, the vehicle type or the traveling direction of the vehicle. be able to. In addition, in the receiving device, the information acquired by each vehicle detector can be aggregated to create more accurate information of the vehicle that has passed over the vehicle detector, so that detailed traffic conditions can be easily grasped. be able to. Note that the receiving device may be a device that transmits a radio wave measured by the vehicle sensor, or may be a device other than a device that transmits the radio wave.

  (10) Preferably, the vehicle detection system further performs a process of synchronizing the reception device and each vehicle sensor by transmitting and receiving time information between the reception device and each vehicle sensor. A part.

  With such a configuration, for example, each vehicle detector can transmit vehicle information at a timing different from that of other vehicle detectors by transmitting vehicle information at a time determined for each vehicle detector. The collision of the radio waves transmitted by each vehicle detector can be avoided. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of vehicle information can be reduced and consumption of electric power can be suppressed. In addition, when the vehicle detection system includes a plurality of vehicle detectors, more accurate vehicle information can be acquired using the radio wave measurement results of the vehicle detectors synchronized with each other.

  (11) The vehicle sensing system according to the embodiment of the present invention is embedded under the road surface on which the vehicle passes or under the road surface on which the vehicle stops, or on the road surface on which the vehicle passes or on the road surface on which the vehicle stops. A transmitter that is installed; and a vehicle detector, wherein the vehicle detector measures an antenna that receives a radio wave transmitted from the transmitter, the radio wave received by the antenna, and changes in measurement results A vehicle information creation unit that creates vehicle information related to the vehicle based on the vehicle, and the antenna is installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. Also, from the change in the value obtained by measuring the radio wave, for example, not only the information on whether or not the vehicle is present above the transmission device but also the information on the speed, vehicle type or traveling direction of the vehicle Therefore, detailed traffic conditions can be easily grasped.

  (12) Preferably, the transmission device operates using power stored in a battery, and the transmission device transmits the radio wave using the road surface antenna, and the sensed radio wave transmission. A sleep control unit that intermittently operates the unit, and the sleep control unit restarts the operation of the sensed radio wave transmission unit when a predetermined condition is satisfied after the operation of the sensed radio wave transmission unit is stopped.

  With such a configuration, the operation of the sensing radio wave transmission unit is stopped when the vehicle does not pass above the transmission device for a predetermined period, and the operation of the sensing radio wave transmission unit is performed when the vehicle is about to pass above the transmission device. Since the intermittent operation such as resumption can be performed, the power consumption of the battery by the vehicle detector can be suppressed, and for example, the replacement frequency of the battery can be reduced. In particular, when a transmitter with a built-in battery or a single battery is buried under a road surface, maintenance costs for the transmitter such as battery replacement work can be effectively reduced.

  (13) Preferably, the vehicle detector further includes a communication unit that communicates with the transmission device by transmitting and receiving signals to and from the transmission device via the measurement antenna, and the vehicle information creation unit includes the measurement result The vehicle information is created on the basis of the change in the signal and whether or not the communication unit can receive the signal transmitted from the transmission device.

  With such a configuration, for example, vehicle information can be created from the measurement result of the radio wave used for the communication in the case where the communication with the other device can be performed satisfactorily, so that the influence of noise and the like is small. More reliable vehicle information can be created using radio waves of good quality.

  (14) A vehicle detector according to an embodiment of the present invention acquires a monitoring unit that monitors a change in a magnetic field, and a timing at which the change in the magnetic field satisfies a predetermined condition based on a monitoring result of the monitoring unit. And a speed calculation unit that calculates the speed of the vehicle based on the timing acquired by the acquisition unit.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using the magnetic field. In addition, it is possible to obtain not only information on whether the vehicle has passed by the vehicle detector from the change in the magnetic field, but also information on the speed of the vehicle, so that detailed traffic conditions can be easily grasped. Can do. In addition, compared to a vehicle detector that measures the speed of a vehicle using radio waves, a set of a configuration for transmitting and receiving radio waves used for vehicle sensing is unnecessary, and a change in magnetic field can be detected with a single configuration. The speed of the vehicle can be obtained with a simpler configuration.

  (15) Preferably, the predetermined condition is that the magnitude of the magnetic field rises from a state where it converges to a predetermined value or a predetermined range and reaches a peak value.

  With such a configuration, for example, a portion that generates a strong magnetic field in the vehicle can acquire the timing at which the vehicle sensor is closest to the vehicle detector. For example, until the peak value is reached after the magnitude of the magnetic field starts to increase. The speed of the vehicle can be calculated based on the time taken for.

  (16) Preferably, the speed calculation unit estimates the position of the specific unit in the vehicle based on the timing acquired by the acquisition unit, and based on the timing acquired by the acquisition unit and the estimated position. The speed of the vehicle is calculated.

  With such a configuration, for example, it is possible to estimate the distance between the tip of the vehicle and the portion that generates a strong magnetic field in the vehicle based on the change in the magnetic field, and based on the change in the magnetic field and the estimated distance, The speed of the vehicle can be calculated. That is, for example, an accurate vehicle speed can be obtained as compared with the case where the speed is calculated on the assumption that the distance is constant regardless of the vehicle.

  (17) More preferably, the acquisition unit has a first timing at which the magnitude of the magnetic field in a state where it converges to a predetermined value or a predetermined range, and the magnitude of the magnetic field peaks after the first timing. A second timing that reaches a value, and a third timing at which the magnitude of the magnetic field decreases and converges to the predetermined value or the predetermined range after the second timing, and the speed calculator is The position is estimated based on the acquired second timing and the third timing, and the speed calculator is configured to determine the first timing and the second timing acquired by the acquisition unit, and the estimated position. Based on this, the speed of the vehicle is calculated.

  With such a configuration, it is possible to obtain a more accurate vehicle speed by paying attention to a plurality of timings acquired based on changes in the magnetic field. Specifically, for example, first, the time taken from when the magnitude of the magnetic field started to reach the peak value and the time taken from when the magnitude of the magnetic field began to rise until it returned to the original value or range. Whether the vehicle is a large vehicle or the like is estimated based on the ratio. Next, the distance between the front end portion of the vehicle and the portion that generates a strong magnetic field in the vehicle is estimated based on an estimation result such as whether or not the vehicle is a large vehicle. Then, by dividing the estimated distance by the time taken to reach the peak value from the time when the magnitude of the magnetic field started to change, a more accurate vehicle speed can be calculated.

  (18) Preferably, the vehicle detector further includes a storage unit that stores information indicating a position of the specific unit in the vehicle, and the speed calculation unit includes the timing acquired by the acquisition unit, and the storage Based on the position indicated by the information stored by the unit, the speed of the vehicle is calculated.

  With such a configuration, for example, in a general vehicle, the distance between the front end of the vehicle and a portion that generates a strong magnetic field can be stored in the storage unit. Can be acquired. And based on the change of a magnetic field and the said distance acquired from the memory | storage part, the speed of a vehicle can be calculated easily.

  (19) Preferably, the acquisition unit includes a second timing at which the magnitude of the magnetic field reaches a peak value, and a second timing at which the magnitude of the magnetic field decreases and converges to a predetermined value or a predetermined range after the second timing. The vehicle detector further calculates a vehicle length based on the speed calculated by the speed calculator and the third timing acquired by the acquirer. A part.

  With such a configuration, for example, the length of the vehicle can be calculated by multiplying the speed of the vehicle by the time taken from when the magnitude of the magnetic field starts to rise to return to the original value or range.

  (20) More preferably, the vehicle detector further includes a determination unit that determines the type of the vehicle based on the length of the vehicle calculated by the vehicle length calculation unit.

  With such a configuration, for example, the vehicle can be classified into one of a large vehicle, a medium vehicle, and a small vehicle according to the length of the vehicle.

  (21) Preferably, the vehicle detector operates using electric power stored in a battery, and the vehicle detector further intermittently operates at least one of the speed calculation unit and the acquisition unit. A sleep control unit, and the sleep control unit stops the operation when a predetermined condition is satisfied after stopping the operation of at least one of the speed calculation unit and the acquisition unit. The operation of at least one of the acquisition units is resumed.

  With such a configuration, for example, when the vehicle does not pass by the vehicle detector for a predetermined period, the operation of the speed calculation unit and the acquisition unit is stopped, and when the vehicle approaches the vehicle detector, the speed calculation unit and acquisition are performed. It is possible to perform an intermittent operation such as resuming the operation of the unit. As a result, it is possible to suppress battery power consumption by the vehicle detector, for example, to reduce the frequency of battery replacement. In particular, when a vehicle sensor with a built-in battery or a single battery is embedded under the road surface, the maintenance cost of the vehicle sensor such as battery replacement work can be effectively reduced.

  (22) Preferably, the vehicle detector further includes a communication unit that transmits vehicle information indicating the speed of the vehicle calculated by the speed calculation unit to a receiving device, and the communication unit transmits the vehicle information. The vehicle information is transmitted to the receiving device when the vehicle detector of its own receives a notification that it can be received or an instruction to transmit the vehicle information from the receiving device.

  With such a configuration, for example, when a plurality of vehicle detectors are installed for one receiving device, each vehicle detector can transmit vehicle information at a different timing from the other vehicle detectors. The collision of radio waves transmitted from each vehicle sensor can be avoided. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of the vehicle information by a vehicle detector can be reduced, and consumption of electric power can be suppressed.

  (23) More preferably, the communication unit repeatedly transmits the vehicle information, and the vehicle detector receives a notification that the reception of the vehicle information is completed from the receiving device. Stop sending information.

  With such a configuration, for example, even when the state of the transmission path between the vehicle detector and the receiving device is bad, the vehicle information can be more reliably transmitted to the receiving device.

  (24) A vehicle detection system according to an embodiment of the present invention includes a reception device and one or more vehicle detectors, wherein the vehicle detector monitors a change in a magnetic field, and the monitoring unit. An acquisition unit that acquires a timing at which the change in the magnetic field satisfies a predetermined condition based on a monitoring result of the vehicle, a speed calculation unit that calculates a vehicle speed based on the timing acquired by the acquisition unit, and the speed calculation A communication unit that transmits vehicle information indicating the speed calculated by the unit to the receiving device, and the receiving device provides comprehensive vehicle information based on the vehicle information received from each of the vehicle detectors. create.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using the magnetic field. Further, from the change in the magnetic field, not only information on whether or not the vehicle has passed by the vehicle detector but also information on the speed of the vehicle can be acquired. In addition, in the receiving device, the information acquired by each vehicle detector can be aggregated to create more accurate information of the vehicle that has passed by the vehicle detector, so that detailed traffic conditions can be easily grasped. be able to. Compared to a vehicle sensing system that measures the speed of a vehicle using radio waves, a configuration for transmitting and receiving radio waves used for vehicle sensing is not necessary, and a change in magnetic field can be detected with a single configuration. The speed of the vehicle can be obtained with a simpler configuration.

  (25) Preferably, the vehicle detection system further performs synchronization processing for synchronizing the reception device and each vehicle sensor by transmitting and receiving time information between the reception device and each vehicle sensor. A part.

  With such a configuration, for example, each vehicle detector can transmit vehicle information at a timing different from that of other vehicle detectors by transmitting vehicle information at a time determined for each vehicle detector. The collision of the radio waves transmitted by each vehicle detector can be avoided. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of vehicle information can be reduced and consumption of electric power can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. Moreover, you may combine arbitrarily at least one part of embodiment described below.

<First Embodiment>
FIG. 1 is a diagram showing a configuration of a vehicle sensing system according to the first embodiment of the present invention.

  With reference to FIG. 1, the vehicle sensing system 101 includes a vehicle sensor 11, a radio device 12, and an antenna 13.

  The radio device 12 is installed beside the road 14 on which the vehicle 10 travels, for example. The wireless device 12 is connected to the antenna 13 and sends an electric signal having a frequency in the RF band to the antenna 13. The vehicle 10 is traveling in the direction indicated by the arrow 70.

  The antenna 13 is installed at a position higher than the road surface of the road 14, that is, above the road 14. The antenna 13 converts an RF band frequency electrical signal received from the wireless device 12 into a radio wave and radiates it to the road 14. As long as the antenna 13 is installed above the road 14, it may be directly above the road 14 or may be on the side of the road 14.

  The vehicle detector 11 is embedded under the road surface of the road 14, for example. The vehicle detector 11 receives the radio wave radiated from the antenna 13 and detects the vehicle 10 passing through the road 14 based on a change in the reception level of the received radio wave.

  Hereinafter, a radio wave emitted from a device other than the vehicle sensor 11 and used for the vehicle sensor 11 to sense the vehicle 10 is also referred to as a sensing radio wave.

  FIG. 2 is a diagram illustrating reception of sensing radio waves by the vehicle detector in the vehicle sensing system according to the first embodiment of the present invention.

  Referring to FIG. 2, vehicle 10 travels above vehicle detector 11, and a part of vehicle 10 is located on a straight line connecting antenna 13 and vehicle detector 11.

  The sensing radio wave radiated from the antenna 13 and traveling straight to the vehicle detector 11 is blocked by the vehicle 10 and therefore does not reach the vehicle detector 11. However, part of the sensing radio wave radiated from the antenna 13 goes around the vehicle 10 from the end of the vehicle 10 and reaches the vehicle detector 11.

  Hereinafter, the sensing radio wave traveling straight to the vehicle detector 11 is also referred to as a direct wave. Further, the sensing radio wave that travels from the end of the vehicle 10 to the lower side of the vehicle 10 is also called a diffracted wave.

  2 indicates a corresponding position of the front end of the vehicle 10 on the road surface, for example, a point on the road surface immediately below the front end of the vehicle 10 and a corresponding position of the antenna of the vehicle detector 11 on the road surface, for example, the antenna of the vehicle detector 11. Indicates the distance to a point on the road directly above.

  For example, the reception level of the sensing radio wave that reaches the vehicle detector 11 by going from the front end of the vehicle 10 to the lower side of the vehicle 10 decreases as the distance L increases.

  FIG. 3 is a diagram illustrating an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the first embodiment of the present invention.

  With reference to FIG. 3, the horizontal axis of the graph indicates time, and the vertical axis indicates the reception level of the sensing radio wave received by the vehicle detector 11. The graph shows the change over time of the reception level of the sensing radio wave received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11.

  The reception level of the sensing radio wave is level Sh when the vehicle 10 is not blocking the direct wave from the radio device 12. The reception level of the sensing radio wave starts to decrease from time t0 when the direct wave from the radio 12 is blocked by the vehicle 10, reaches a level Sb at time t1, and becomes constant. The level Sb is a measurement lower limit of the reception level by the vehicle detector 11, and is, for example, the reception level of floor noise.

  The reception level of the sensing radio wave starts to rise from time t2, and returns to level Sh at time t3 when the vehicle detector 11 starts receiving the direct wave from the radio 12 again.

  Further, a period Ta from time t0 to time t3, a period Tb from time t0 to time t1, a period Tc from time t1 to time t2, and a period Td from time t2 to time t3 depend on the speed of the vehicle 10. For example, the higher the speed of the vehicle 10, the shorter.

  Further, the period Tb and the period Td are constant regardless of the length of the vehicle 10 when the speed of the vehicle 10 is constant. On the other hand, the period Ta and the period Tc depend on the vehicle length of the vehicle 10 even when the speed of the vehicle 10 is constant. For example, the period Ta and the period Tc become longer as the vehicle 10 is longer.

In general, the higher the frequency of a radio wave, the more difficult it is to go into the shadow of an object, that is, a property that it is difficult to diffract. Therefore, depending on the frequency of the sensing radio wave, the period Tb and the period Td depend on the height of the bottom surface of the vehicle 10.
The wireless device 12 radiates sensing radio waves having a frequency that does not depend greatly on the height of the bottom surface of the vehicle 10 during the period Tb and the period Td.

  Here, when the vehicle length of the vehicle 10 is constant, for example, the ratio of Ta and Tc is constant regardless of the speed of the vehicle 10. Therefore, when the vehicle length of the vehicle 10 is constant, Tc / Ta is constant.

  On the other hand, Tc / Ta varies depending on the vehicle length of the vehicle 10. Specifically, when the vehicle 10 has a long vehicle length, Tc / Ta increases, and when the vehicle 10 has a short vehicle length, Tc / Ta decreases.

  Therefore, the vehicle detector 11 can obtain the vehicle length of the vehicle 10 based on Tc / Ta. Further, the vehicle detector 11 classifies the vehicle type of the vehicle 10 as a small vehicle or a large vehicle based on a predetermined threshold value based on, for example, Tc / Ta.

  Ta is a period during which the vehicle 10 is blocking direct waves, that is, after the front end of the traveling vehicle 10 has reached a specific position on the road 14, the rear end of the vehicle 10 is at the specific position. It is a period until it passes. Therefore, when the vehicle length of the vehicle 10 obtained based on Tc / Ta is D, the vehicle detector 11 calculates the speed of the vehicle 10 based on D / Ta.

  FIG. 4 is a diagram showing the configuration of the vehicle detector according to the first embodiment of the present invention.

  With reference to FIG. 4, the vehicle detector 11 includes an antenna 31, a communication unit 32, a vehicle information creation unit 33, a sleep control unit 34, a management unit 35, a storage unit 36, a battery unit 37, And a magnetic sensor 38.

  The vehicle sensor 11 operates using, for example, electric power stored in a battery. Specifically, the battery unit 37 includes the battery, converts the output of the battery into a predetermined voltage level, and supplies it to the entire vehicle detector 11.

  The vehicle detector 11 is not limited to the configuration including the battery unit 37, and may be configured to not include the battery unit 37. When the vehicle detector 11 does not include the battery unit 37, the vehicle detector 11 is supplied with power from, for example, a battery installed outside the vehicle detector 11.

  The antenna 31 is embedded under the road surface of the road 14 through which the vehicle 10 passes together with other units in the vehicle detector 11, and receives sensing radio waves from other devices such as the radio device 12. The antenna 31 converts the received sensing radio wave into an electrical signal and sends it to the communication unit 32, the vehicle information creation unit 33, and the sleep control unit 34.

  The antenna 31 is not limited to the road surface of the road 14 through which the vehicle 10 passes, and may be installed on the road surface of the road 14 through which the vehicle 10 passes. Moreover, the antenna 31 may be embed | buried under the road surface where the vehicle 10 stops like a parking lot, for example, and may be installed in the road surface where the vehicle 10 stops.

  The antenna 31 is also used for communication between the vehicle detector 11 and the wireless device 12. For example, the antenna 31 receives an electrical signal from the communication unit 32, converts the received electrical signal into a radio wave, and transmits the radio signal to the wireless device 12.

  The communication unit 32 communicates with the wireless device 12 by transmitting and receiving signals to and from the wireless device 12 that transmits radio waves via the antenna 31. Specifically, the communication unit 32 transmits information received from the management unit 35 to the wireless device 12 via the antenna 31, and transmits information received from the wireless device 12 via the antenna 31 to the management unit 35.

  The vehicle information creation unit 33 measures the sensing radio wave received by the antenna 31 and creates vehicle information related to the vehicle 10 based on a change in the measurement result. Specifically, the vehicle information creation unit 33 measures the level of the electric signal received from the antenna 31 at predetermined intervals, and for example, information on the relationship between time and reception level as shown in FIG. 3 (hereinafter, also referred to as time level information). To create).

  Further, the vehicle information creation unit 33 calculates Tc / Ta from Ta and Tc included in the created time level information to obtain the vehicle length D of the vehicle 10, and determines the vehicle type of the vehicle 10 based on the vehicle length D. To do.

  The vehicle information creation unit 33 creates vehicle length information indicating the vehicle length D of the vehicle 10 and vehicle type information indicating the vehicle type of the vehicle 10.

  Moreover, the vehicle information creation unit 33 calculates D / Ta, calculates the speed of the vehicle 10 based on D / Ta, and creates speed information indicating the speed of the vehicle 10.

  The vehicle information creation unit 33 sends the created time level information, vehicle length information, vehicle type information, and speed information to the management unit 35.

  The management unit 35 stores time level information, vehicle length information, vehicle type information, and speed information, which are vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  The sleep control unit 34 operates the vehicle information creation unit 33 intermittently. Specifically, for example, when the sleep control unit 34 determines that the vehicle 10 has not passed over the vehicle detector 11 for a predetermined period based on the level of the electrical signal received from the antenna 31, vehicle information creation is performed. The operation of the unit 33 is stopped.

  In addition, after stopping the operation of the vehicle information creation unit 33, the sleep control unit 34 resumes the operation of the vehicle information creation unit 33 when a predetermined condition is satisfied.

  Specifically, for example, the sleep control unit 34 monitors the level of the electrical signal received from the antenna 31, and when there is a change in the level, the sleep control unit 34 detects the approach of the vehicle 10 from the change in the level, and vehicle information The operation of the creation unit 33 is resumed. The vehicle information creation unit 33 measures the reception level of the sensing radio wave and creates vehicle information related to the vehicle 10 based on the change in the measurement result.

  For example, most of the vehicle body of the vehicle 10 is made of metal, and a strong magnetic field is generated around a dynamo that the vehicle 10 generally includes. Therefore, when the vehicle 10 approaches the vehicle sensor 11, the magnetic field level or the magnetic field direction in the vehicle sensor 11 changes.

  The magnetic sensor 38 measures the magnetic field level or the magnetic field direction in the vehicle sensor 11 and sends the measurement result to the sleep control unit 34.

  The sleep control unit 34 monitors the measurement result of the level of the magnetic field received from the magnetic sensor 38 or the direction of the magnetic field. For example, when there is a change in the measurement result, the sleep control unit 34 detects the approach of the vehicle 10 from the change in the measurement result. The operation of the vehicle information creation unit 33 is resumed.

  Note that the antenna 31 is not limited to a configuration that is installed below or on the road surface together with other units in the vehicle detector 11, and may be installed at a location separate from the other units. In this case, the other unit may be installed above the road surface, for example.

  Further, the vehicle information creation unit 33 calculates the average speed, the number of vehicles, and the occupation rate of the vehicle 10 during a predetermined period from the measurement result of the reception level of the sensing radio wave, and creates vehicle information indicating the calculation result. Good. Here, the occupation ratio refers to the ratio of the time during which the vehicle 10 exists above the vehicle detector 11. In general, the occupation rate increases as the traffic volume increases.

  Further, the vehicle detection system 101 is not limited to a configuration in which one vehicle sensor 11 is installed for one radio device 12, and a configuration in which a plurality of vehicle sensors 11 are installed for one radio device 12. It may be.

  FIG. 5 is a diagram illustrating an example of a sequence in which the vehicle detector in the vehicle detection system transmits vehicle information to the wireless device.

  Each device in the vehicle sensing system includes a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including a part or all of each step of the sequence shown below from a memory (not shown). Each of the programs of the plurality of apparatuses can be installed from the outside. The programs of the plurality of apparatuses are distributed while being stored in a recording medium.

  FIG. 5 shows a case where two vehicle detectors 11 </ b> A and 11 </ b> B are installed for one wireless device 12.

  Referring to FIG. 5, the wireless device 12 radiates a sensing radio wave toward the road 14 (step S11). The vehicle detector 11A and the vehicle detector 11B receive the sensing radio wave radiated from the wireless device 12, and sense the passing vehicle 10 based on the change in the reception level of the received sensing radio wave.

  Next, when detecting the vehicle 10, the vehicle detector 11A creates vehicle information of the vehicle 10 (step S12), and stores the created vehicle information in the storage unit 36 (step S13). Each time the vehicle 10 passes, the vehicle detector 11A creates vehicle information of the vehicle 10 and stores it in the storage unit 36 (steps S12 and S13).

  Further, when the vehicle detector 11B senses the vehicle 10, the vehicle sensor 11B creates vehicle information of the vehicle 10 (step S14), and stores the created vehicle information in the storage unit 36 (step S15). Each time the vehicle 10 passes, the vehicle detector 11B creates vehicle information about the vehicle 10 and stores it in the storage unit 36 (steps S14 and S15).

  Next, the vehicle information receiving device, for example, the wireless device 12 transmits a reception enable notification to the vehicle detector 11A as a notification that the vehicle information can be received (step S16).

  Next, the vehicle detector 11A receives a reception enable notification from the wireless device 12 and, if the vehicle information is stored in its own storage unit 36, transmits the vehicle information to the wireless device 12 (step). S17).

  Specifically, in the vehicle detector 11 </ b> A, the management unit 35 extracts vehicle information from the storage unit 36 and sends the vehicle information to the communication unit 32 when a receivable notification is received from the wireless device 12 via the communication unit 32. The communication unit 32 transmits the vehicle information received from the management unit 35 to the wireless device 12.

  Next, when the wireless device 12 appropriately receives the vehicle information transmitted from the vehicle detector 11A, the wireless device 12 transmits a reception completion notification to the vehicle detector 11A as a notification that reception of the vehicle information has been completed ( Step S18).

  Here, the vehicle detector 11 </ b> A repeatedly transmits the vehicle information to the wireless device 12 until the reception of the reception completion notification from the wireless device 12 after first transmitting the vehicle information to the wireless device 12.

  Specifically, for example, in the vehicle detector 11 </ b> A, the communication unit 32 repeatedly transmits the vehicle information to the wireless device 12, and the vehicle detector 11 </ b> A receives a reception completion notification of the vehicle information from the wireless device 12. Then, the transmission of the vehicle information is stopped.

  Next, the vehicle detector 11A receives the reception completion notification from the wireless device 12 and deletes the vehicle information transmitted to the wireless device 12 from its own storage unit 36 (step S19).

  Next, the wireless device 12 transmits a receivable notification to the vehicle detector 11B (step S20).

  Next, the vehicle detector 11B receives the reception enable notification from the wireless device 12 and, if the vehicle information is stored in its own storage unit 36, transmits the vehicle information to the wireless device 12 (step). S21). Further, the vehicle detector 11B repeatedly transmits the vehicle information to the radio device 12 until receiving the reception completion notification from the radio device 12.

  Next, when the wireless device 12 appropriately receives the vehicle information transmitted from the vehicle detector 11B, the wireless device 12 transmits a reception completion notification to the vehicle detector 11B (step S22).

  Next, the vehicle sensor 11B receives the reception completion notification from the wireless device 12 and deletes the vehicle information transmitted to the wireless device 12 from its own storage unit 36 (step S23).

  Next, the wireless device 12 creates comprehensive vehicle information based on the vehicle information received from the vehicle detector 11A and the vehicle information received from the vehicle detector 11B (step S24).

  For example, when one vehicle 10 travels on the road 14 and a plurality of vehicle detectors 11 create vehicle information for the vehicle 10 and transmit it to the radio device 12, the radio device 12 Vehicle information received from each vehicle detector 11 within a predetermined interval is associated with each other as vehicle information related to the specific vehicle 10. Then, the wireless device 12 creates more accurate vehicle information from the vehicle information associated with each other.

  Specifically, for example, the wireless device 12 acquires the speed of the vehicle 10 calculated by each vehicle sensor 11 from a plurality of vehicle information associated with each other, and averages the acquired speeds of the vehicle 10. A more accurate speed of the vehicle 10 is calculated.

  Further, for example, the wireless device 12 acquires the vehicle length of the vehicle 10 calculated by each vehicle sensor 11 from a plurality of vehicle information associated with each other, and averages the vehicle lengths of the acquired vehicles 10. A more accurate vehicle length of the vehicle 10 is calculated. Then, the wireless device 12 determines the vehicle type of the vehicle 10 from the calculated vehicle length of the vehicle 10.

  Further, for example, the wireless device 12 accumulates information indicating the speed of the vehicle 10 calculated by itself and the vehicle type of the vehicle 10 determined by itself for a predetermined period, and calculates the average speed and the number of vehicle types of the vehicle 10 in the period. To do.

  Note that the wireless device 12 is not limited to the configuration that transmits a receivable notification to the vehicle detector 11 and may transmit a vehicle information transmission instruction. When the vehicle sensor 11 receives a vehicle information transmission instruction from the wireless device 12, the management unit 35 in the vehicle sensor 11 extracts the vehicle information from the storage unit 36 and sends the vehicle information to the communication unit 32. The communication unit 32 transmits the vehicle information received from the management unit 35 to the wireless device 12.

  Further, the vehicle detector 11 is not limited to the configuration provided with the magnetic sensor 38, and may be configured without the magnetic sensor 38, or may be configured with a vibration sensor instead of the magnetic sensor 38.

  When the vehicle sensor 11 includes a vibration sensor instead of the magnetic sensor 38, the vibration sensor measures, for example, vibration of the road 14 and sends the measurement result to the sleep control unit 34.

  The sleep control unit 34 monitors the measurement result obtained by the vibration sensor. When there is a change in the vibration measurement result, for example, the sleep control unit 34 senses the approach of the vehicle 10 and restarts the operation of the vehicle information creation unit 33.

  In addition, the sleep control unit 34 may repeatedly stop the operation of the vehicle information creation unit 33 and restart the operation at predetermined intervals, for example, according to statistical accuracy required for the vehicle sensing system.

  Further, the management unit 35 may compress the vehicle information and store it in the storage unit 36. The management unit 35 may transmit vehicle information in a compressed state. When the management unit 35 compresses and transmits information, the power consumption of the battery in the battery unit 37 can be suppressed.

  The vehicle information creation unit 33 is not limited to a configuration that creates all of the time level information, the vehicle length information, the vehicle type information, and the speed information.

  For example, when the vehicle information creation unit 33 creates only time level information among these pieces of information, the vehicle detector 11 transmits the time level information to the wireless device 12 as vehicle information.

  The wireless device 12 receives time level information from the vehicle detector 11, and creates comprehensive vehicle information such as vehicle length information, vehicle type information, speed information, and the like based on the received time level information.

  By the way, in the vehicle detection system described in Patent Document 1 and the vehicle sensor described in Patent Document 2, it is not possible to detect the speed of the vehicle 10 or the type of the vehicle 10, so it is necessary to grasp a more detailed traffic situation. There are not enough for some applications.

  On the other hand, in the vehicle sensor according to the first embodiment of the present invention, the antenna 31 receives a sensing radio wave transmitted from the wireless device 12. The vehicle information creation unit 33 measures the sensing radio wave received by the antenna 31 and creates vehicle information related to the vehicle 10 based on a change in the measurement result. The antenna 31 is embedded under the road surface on which the vehicle 10 passes or under the road surface on which the vehicle 10 stops, or on the road surface on which the vehicle 10 passes or on the road surface on which the vehicle 10 stops.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. Further, from the change in the value obtained by measuring the sensing radio wave, for example, not only the information on whether or not the vehicle 10 exists above the vehicle detector 11 but also the information on the speed or vehicle type of the vehicle 10. Since it can be acquired, it is possible to easily grasp the detailed traffic situation.

  Moreover, in the vehicle sensor which concerns on the 1st Embodiment of this invention, the sleep control part 34 operates the vehicle information preparation part 33 intermittently. After stopping the operation of the vehicle information creation unit 33, the sleep control unit 34 resumes the operation of the vehicle information creation unit 33 when a predetermined condition is satisfied. Further, the vehicle detector 11 operates using electric power stored in the battery.

  With such a configuration, when the vehicle 10 does not pass over the vehicle detector 11 for a predetermined period, the operation of the vehicle information creation unit 33 is stopped, and the vehicle 10 is about to pass over the vehicle detector 11. Since an intermittent operation such as resuming the operation of the vehicle information creation unit 33 can be performed, the power consumption of the battery by the vehicle detector 11 can be suppressed, and for example, the frequency of battery replacement can be reduced. In particular, when the vehicle sensor 11 with a built-in battery or a single battery is embedded under the road surface, the maintenance cost of the vehicle sensor 11 such as battery replacement work can be effectively reduced.

  Further, in the vehicle sensor according to the first embodiment of the present invention, the communication unit 32 gives a notification that the vehicle information can be received or an instruction to transmit the vehicle information. Vehicle information is transmitted to the wireless device 12.

  With such a configuration, for example, when a plurality of vehicle detectors 11 are installed for one radio device 12, each vehicle detector 11 transmits vehicle information at a different timing from the other vehicle detectors 11. Therefore, it is possible to avoid collision of sensing radio waves transmitted from the vehicle detectors 11. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of the vehicle information by the vehicle detector 11 can be reduced, and consumption of electric power can be suppressed.

  Further, in the vehicle detector according to the first embodiment of the present invention, the communication unit 32 repeatedly transmits vehicle information, and the vehicle detector 11 of its own transmits a notification that the reception of the vehicle information is completed. When receiving from 12, the transmission of vehicle information is stopped.

  With such a configuration, for example, even when the state of the transmission path between the vehicle detector 11 and the wireless device 12 is poor, vehicle information can be transmitted to the wireless device 12 more reliably.

  In the vehicle sensing system according to the first embodiment of the present invention, the antenna 31 receives a sensing radio wave transmitted from a device other than the vehicle detector 11. The vehicle information creation unit 33 measures the sensing radio wave received by the antenna 31 and creates vehicle information related to the vehicle 10 based on a change in the measurement result. The communication unit 32 transmits vehicle information to the wireless device 12. The antenna 31 is embedded under the road surface through which the vehicle 10 passes or under the road surface where the vehicle 10 stops, or is installed on the road surface through which the vehicle 10 passes or the road surface where the vehicle stops. The wireless device 12 creates comprehensive vehicle information based on the vehicle information received from each vehicle sensor 11.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. In addition, in each vehicle detector 11, not only information on whether or not the vehicle 10 exists above the vehicle detector 11, for example, from the change in the value obtained by measuring the sensing radio wave, Information such as speed or vehicle type can also be acquired. Further, since the radio device 12 can collect information acquired by each vehicle detector 11 and create more accurate information of the vehicle 10 that has passed over the vehicle detector 11, detailed traffic conditions can be obtained. It can be easily grasped.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to a vehicle sensing system that differs in speed calculation method from the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 6 is a diagram showing an example of the relationship between the distance L shown in FIG. 2 and the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the second embodiment of the present invention.

  Referring to FIG. 6, the horizontal axis of the graph indicates the distance L, and the vertical axis indicates the reception level of the sensing radio wave received by the vehicle detector 11. The graph shows the change over time of the reception level of the sensing radio wave received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11.

  The reception level of the sensing radio wave is level Sh when the vehicle 10 is not blocking the direct wave from the radio device 12. The reception level of the sensing radio wave starts to decrease from the position of L = 0 where the direct wave from the wireless device 12 is blocked by the vehicle 10, reaches a level Sb at a distance L1, and becomes constant. The level Sb is a measurement lower limit of the reception level by the vehicle detector 11, and is, for example, the reception level of floor noise.

  Then, the reception level of the sensing radio wave starts to rise from the distance L2, and returns to the level Sh at the distance L3 at which the vehicle detector 11 starts receiving the direct wave from the wireless device 12 again.

  Hereinafter, the time from the time t0 when L = 0 to the time t1 when L = L1 is also referred to as a reception level falling time.

  The period from time t2 when L = L2 to time t3 when L = L3 is also referred to as a reception level rise time.

  For example, the distance L1 is constant regardless of the speed of the vehicle 10 and the vehicle length. On the other hand, the fall time of the reception level depends on the speed of the vehicle 10, and becomes smaller as the speed of the vehicle 10 is higher, for example.

  Therefore, the vehicle detector 11 can obtain the speed of the vehicle 10 based on the distance L1 and the fall time of the reception level.

  Depending on the frequency of the sensing radio wave, the distance L1 depends on the height of the bottom surface of the vehicle body of the vehicle 10, but the wireless device 12 has a frequency at which the distance L1 does not greatly depend on the height of the bottom surface of the vehicle body of the vehicle 10. Radiates sensing radio waves.

  FIG. 4 also shows the configuration of the vehicle detector according to the second embodiment of the present invention.

  Referring to FIG. 4, storage unit 36 stores distances L1, L2, and L3 obtained by an experiment performed in advance, for example.

  The vehicle information creation unit 33 measures the reception level of the sensing radio wave received by the antenna 31, and acquires time t1 and time t2 from the measurement result. Further, the vehicle information creation unit 33 acquires the distance L1 from the storage unit 36 via the management unit 35.

Here, if the speed of the vehicle 10 based on the falling time of the reception level is Va, the vehicle information creation unit 33 calculates the speed Va according to the following formula.
Va = L1 / (t1-t0)

Similarly, the vehicle information creation unit 33 calculates the speed of the vehicle 10 based on the rising time of the reception level. Assuming that the speed of the vehicle 10 based on the rising time of the reception level is Vb, the vehicle information creation unit 33 calculates the speed Vb according to the following formula.
Vb = (L3-L2) / (t3-t2)

  Moreover, the vehicle information creation part 33 can obtain | require the speed of the vehicle 10 more accurately using both the speed Va and the speed Vb. For example, the vehicle detector 11 can calculate the average value of the speed Va and the speed Vb as the speed of the vehicle 10.

  Further, as described above, the distance L1 depends on the height of the bottom surface of the vehicle 10 depending on the frequency of the sensing radio wave radiated from the radio device 12. When the radio device 12 emits a sensing radio wave having a frequency whose distance L1 depends on the height of the bottom of the vehicle body of the vehicle 10, the distance L1 increases as the vehicle height of the vehicle 10 increases, and the vehicle height of the vehicle 10 increases. The lower the value, the smaller. The height of the vehicle body varies depending on the type of the vehicle 10, and for example, large vehicles tend to be high and small vehicles tend to be low.

  When the height of the bottom of the vehicle body of the vehicle 10 greatly affects the distance L1, for example, when calculating the speed Va, the vehicle detector 11 switches the distance L1 used for calculating the speed Va for each vehicle type.

  Hereinafter, the distance L1 when the vehicle 10 is a large vehicle is referred to as a distance Lbb, and the distance L1 when the vehicle 10 is a small vehicle is referred to as a distance Lss. The distance Lbb is, for example, an average value of the distances L1 of a plurality of large vehicles obtained by an experiment performed in advance. The distance Lss is, for example, an average value of the distances L1 of a plurality of small cars obtained by an experiment performed in advance. The storage unit 36 stores a distance Lbb and a distance Lss in advance.

  The vehicle information creation unit 33 measures the level of the electric signal received from the antenna 31 at a predetermined interval. And the vehicle information creation part 33 acquires the time t0 and the time t1 from a measurement result.

  Moreover, the vehicle information creation part 33 acquires Tc and Ta shown in FIG. 3 from the said measurement result, and calculates Tc / Ta. And the vehicle information creation part 33 determines the vehicle type of the vehicle 10 based on Tc / Ta.

  The vehicle detector 11 selects and acquires either the distance Lbb or the distance Lss stored in the storage unit 36 according to the determination result of the vehicle type, and uses the acquired distance Lbb or the distance Lss. Calculate the speed.

Specifically, the vehicle information creation unit 33 calculates the speed of the vehicle 10 using one of the following formulas according to the vehicle type of the vehicle 10.
Va = Lbb / (t1-t0)
Va = Lss / (t1-t0)

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Third Embodiment>
The present embodiment relates to a vehicle sensing system in which the vehicle type determination method and the speed calculation method are different from those of the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 7 is a diagram illustrating an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the third embodiment of the present invention.

  With reference to FIG. 7, the horizontal axis of the graph represents time, and the vertical axis represents the reception level of the sensing radio wave received by the vehicle detector 11. The graph shows the change over time of the reception level of the sensing radio wave received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11.

  The reception level of the sensing radio wave is level Sh when the vehicle 10 is not blocking the direct wave from the radio device 12. The reception level of the sensing radio wave begins to decrease from time t0 when the direct wave from the radio 12 is blocked by the vehicle 10, and decreases to the level Sb that is the lowest reception level at time t1. Then, the reception level of the sensing radio wave rises from time t1, and returns to level Sh at time t2 when the vehicle detector 11 starts receiving the direct wave from the wireless device 12 again.

  The level Sb indicates a lower limit of measurement of the reception level by the vehicle detector 11, and is a floor noise reception level, for example. Ta represents a period from t0 to t2.

  In the graph shown in FIG. 7, the reception level of the sensing radio wave is not lowered to the level Sb as compared with the graph shown in FIG. For example, when the frequency of the sensing radio wave emitted by the antenna 13 is low, Su is higher than Sb because the sensing radio wave is easily diffracted.

  In addition, when the frequency of the sensing radio wave radiated from the antenna 13 is low, the sensing radio wave is easily diffracted. Therefore, the reception level of the sensing radio wave is hardly affected by the difference in the height of the bottom surface of the vehicle 10. .

  The vehicle sensor 11 determines the vehicle type of the vehicle 10 based on the time during which the vehicle 10 is blocking direct waves and the degree of reception level received.

  Specifically, for example, the vehicle type of the vehicle 10 is determined by comparing with a predetermined threshold value. When determining the vehicle type of the vehicle 10, the threshold value to be compared with the period Ta is Tth, and the threshold value to be compared with the level Su is Sth.

  FIG. 4 also shows the configuration of a vehicle sensor according to the third embodiment of the present invention.

  Referring to FIG. 4, storage unit 36 stores threshold value Tth and threshold value Sth in advance. The vehicle information creation unit 33 measures the sensing radio wave received by the antenna 31 and acquires the level Su and the period Ta from the measurement result. Further, the vehicle information creation unit 33 acquires the threshold value Sth and the threshold value Tth from the storage unit 36 via the management unit 35.

  The vehicle information creation unit 33 compares the period Ta with the threshold value Tth, compares the level Su with the threshold value Sth, classifies the cases based on these comparison results, and determines the vehicle type of the vehicle 10. .

  Specifically, for example, when Su ≦ Sth and Ta ≧ Tth, the vehicle information creation unit 33 determines that the vehicle 10 is a large vehicle. When Su ≧ Sth and Ta ≦ Tth, the vehicle information creation unit 33 determines that the vehicle 10 is a small vehicle. In other cases, the vehicle information creation unit 33 determines that the vehicle 10 is a medium-sized vehicle.

  Then, the vehicle information creation unit 33 creates vehicle type information indicating the determined vehicle type of the vehicle 10 and sends the created vehicle type information to the management unit 35.

  The management unit 35 stores the vehicle type information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Further, the vehicle information creation unit 33 calculates the average speed of the one or more vehicles 10 based on the determination result of the vehicle type of the one or more vehicles 10.

  Here, the average speed of the vehicle 10 passing above the vehicle detector 11 is Vav, the ratio of the large vehicle that makes the vehicle 10 passing above the vehicle detector 11 is α, and the vehicle 10 passes above the vehicle detector 11. The number of vehicles 10 is N, the average vehicle length of the vehicles 10 passing above the vehicle detector 11 is Dav, and the sum of the periods Ta shown in FIG. 7 of the vehicles 10 passing above the vehicle detector 11 is W And

  Also, let Db be the average vehicle length of large vehicles, and Ds be the average vehicle length of non-large vehicles. The storage unit 36 stores a vehicle length Db and a vehicle length Ds in advance.

  The vehicle information creation unit 33 counts the number N of vehicles 10 passing above the vehicle detector 11 based on, for example, a change in the electrical signal received from the antenna 31. Further, among the vehicles 10 passing above the vehicle detector 11, for example, the number of vehicles 10 determined as large vehicles by the above-described case division is counted. The vehicle information creation unit 33 calculates the ratio α of large vehicles based on the number N and the number of large vehicles.

The vehicle information creation unit 33 acquires the vehicle length Db and the vehicle length Ds from the storage unit 36 via the management unit 35, and calculates the vehicle length Dav according to the following formula.
Dav = (1−α) × Ds + α × Db

Moreover, the vehicle information creation part 33 calculates average speed Vav according to the following formula | equation.
Vav = N × Dav / W

  The vehicle information creation unit 33 creates average speed information indicating the average speed Vav, and sends the created average speed information to the management unit 35.

  The management unit 35 stores average speed information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Note that the wireless device 12 is not limited to a configuration that radiates a single-frequency sensing radio wave, and may radiate a radio wave obtained by modulating a signal including specific data as a sensing radio wave.

  When the vehicle detector 11 receives the sensing radio wave, the vehicle information creating unit 33 is based on the change in the measurement result of the sensing radio wave and whether the communication unit 32 can receive the signal transmitted from the wireless device 12. Create vehicle information. Specifically, when the communication unit 32 can receive the signal transmitted from the wireless device 12, that is, when the communication unit 32 can restore the original data from the sensing radio wave received by the antenna 31, vehicle information creation The unit 33 creates, for example, vehicle type information and average speed information using the sensing radio wave.

  When the communication unit 32 can restore the original data, it is possible to estimate that the value of the reception level Su is not affected by noise because the noise received by the antenna 31 from the surroundings is small.

  Therefore, the vehicle information creation unit 33 can increase the accuracy of vehicle type determination, for example, by creating vehicle information only when the communication unit 32 can restore the original data.

  The vehicle information creation unit 33 may determine the vehicle type based on the level Su. Specifically, for example, the vehicle information creation unit 33 compares the threshold value Su that is lower than the level Sh by a predetermined value with the level Su.

  The vehicle information creation unit 33 determines that the vehicle 10 is a large vehicle when the level Su is below the threshold value, and when the level Su is above the threshold value, It is determined that the vehicle 10 is other than a large vehicle.

  The vehicle information creation unit 33 may create the vehicle information based on the angle of the polarization plane of the sensing radio wave received by the antenna 31. For example, when the sensing radio wave is reflected by the vehicle 10, the angle of the polarization plane in the sensing radio wave after reflection changes with respect to the angle of the polarization plane in the sensing radio wave before reflection.

  The vehicle information creation unit 33 determines whether the sensing radio wave is a sensing radio wave reflected by the vehicle 10 from the angle of the polarization plane of the sensing radio wave received by the antenna 31.

  The vehicle information creation unit 33 can create more accurate vehicle information by not using the sensing radio wave reflected by the vehicle 10 when creating the vehicle information.

  As described above, in the vehicle detector according to the third embodiment of the present invention, the communication unit 32 communicates with the wireless device 12 by transmitting and receiving signals to and from the wireless device 12 via the antenna 31. The vehicle information creation unit 33 creates vehicle information based on the change in the measurement result and whether or not the communication unit 32 can receive the signal transmitted from the wireless device 12.

  With such a configuration, for example, vehicle information can be created from the measurement result of the sensing radio wave used for the communication when the communication with the wireless device 12 can be satisfactorily performed. It is possible to create more reliable vehicle information by using a sensing radio wave with less quality and good quality.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Fourth embodiment>
The present embodiment relates to a vehicle sensing system in which the vehicle type determination method and the speed calculation method are different from those of the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 8 is a diagram illustrating reception of radio waves for detection by the vehicle detector in the vehicle detection system according to the fourth embodiment of the present invention.

  Referring to FIG. 8, vehicle 10 travels in the direction of arrow 70 and is close to antenna 13 and vehicle detector 11.

  A part of the sensing radio wave radiated from the antenna 13 reaches the vehicle detector 11 after being reflected by the front portion of the vehicle 10.

  When a part of the sensing radio wave reaches the vehicle detector 11 after being reflected by the front part of the vehicle 10, the power of the reflected wave of the sensing radio wave increases as the front part of the vehicle 10 becomes wider. The reception level of the sensing radio wave in the device 11 becomes high.

  Here, in general, the front portion of a large vehicle is wide, and the front portion of a small vehicle is narrow. Therefore, the vehicle detector 11 can determine the vehicle type of the vehicle 10 by measuring the reception level of the sensing radio wave reflected by the vehicle 10.

  Further, after the vehicle 10 passes between the antenna 13 and the vehicle detector 11, similarly, a part of the radio wave radiated from the antenna 13 is reflected on the rear surface portion of the vehicle 10 and reaches the vehicle detector 11. To do.

  When a part of the radio wave radiated from the antenna 13 is reflected on the rear surface portion of the vehicle 10 and reaches the vehicle detector 11, the larger the rear surface portion of the vehicle 10 is, the larger the power of the reflected wave of the detection radio wave is. Therefore, the reception level of the sensing radio wave in the vehicle detector 11 is increased.

  Hereinafter, the sensing radio wave that reaches the vehicle detector 11 after being reflected from the front surface portion of the vehicle 10 is also referred to as a front surface reflected wave. Further, the sensing radio wave that reaches the vehicle detector 11 after being reflected from the rear surface portion of the vehicle 10 is also referred to as a rear surface reflected wave.

  FIG. 9 is a diagram illustrating an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the fourth embodiment of the present invention.

  Referring to FIG. 9, the horizontal axis of the graph indicates time, and the vertical axis indicates the reception level of the sensing radio wave received by the vehicle detector 11. The graph shows the change over time of the reception level of the sensing radio wave received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11.

  The reception level of the sensing radio wave is level Sh when the vehicle 10 is sufficiently away from the antenna 13 and the vehicle detector 11. The reception level of the sensing radio wave starts to rise from the time t0 when the vehicle detector 11 starts to receive the front-surface reflected wave, reaches the first peak level Sra at the time t1, and starts to fall.

  Then, the reception level of the sensing radio wave becomes equal to or lower than level Sh near time t2 when the direct wave from the radio 12 is blocked by the vehicle 10, and reaches level Sb at time t3. The level Sb is a measurement lower limit of the reception level by the vehicle detector 11, and is, for example, the reception level of floor noise.

  Then, the reception level of the sensing radio wave starts to increase from time t4 and becomes equal to or higher than level Sh near time t5 at which the vehicle detector 11 begins to receive the rear surface reflected wave.

  Then, the reception level of the sensing radio wave reaches the second peak level Srb at time t6 and starts to drop, and returns to level Sh at time t7 when the vehicle detector 11 does not receive the rear reflection wave. .

  The vehicle detector 11 determines the vehicle type of the vehicle 10 based on the level Sra and the level Srb.

  Specifically, for example, the vehicle detector 11 provides a threshold value Srt corresponding to a level higher than the level Sh by a predetermined value, and compares the level Sra and the level Srb with the threshold value Srt, respectively. Then, the vehicle detector 11 determines the vehicle type of the vehicle 10 based on the comparison result.

  FIG. 4 also shows the configuration of a vehicle sensor according to the fourth embodiment of the present invention.

  Referring to FIG. 4, storage unit 36 stores threshold value Srt in advance. The vehicle information creation unit 33 measures the level of the sensing radio wave received by the antenna 31 and acquires the level Sra and the level Srb from the measurement result.

  Further, the vehicle information creation unit 33 acquires the threshold value Srt from the storage unit 36 via the management unit 35. Then, the vehicle information creation unit 33 compares the level Sra, the level Srb, and the threshold value Srh respectively, and determines the vehicle type of the vehicle 10 based on the comparison result.

  Specifically, for example, vehicle information creation unit 33 determines that vehicle 10 is a large vehicle when one or both of level Sra and level Srb exceed threshold value Srt. Moreover, the vehicle information preparation part 33 determines with the vehicle 10 being a normal vehicle, for example, when neither the level Sra nor the level Srb exceeds the threshold value Srt.

  Then, the vehicle information creation unit 33 creates vehicle type information indicating the determined vehicle type of the vehicle 10 and sends the created vehicle type information to the management unit 35.

  The management unit 35 stores the vehicle type information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Further, due to the Doppler effect, the frequency of the sensing radio wave before reflection is different from the frequency of the sensing radio wave after reflection. The vehicle information creation unit 33 calculates the vehicle 10 based on the frequency of the sensing radio wave before reflection and the frequency of the sensing radio wave after reflection.

For example, when a radio wave T1 (t) represented by the following equation (1) is reflected on the surface of the object Y approaching the radio wave radiation source at a velocity vd, the radio wave R1d (after reflection) observed at the radiation source t) is expressed by the following equation (2).

  Here, φ1 is an initial phase. A is the amplitude of the radio wave before reflection. L is the distance between the radio wave radiation source and the object Y. c is the speed of light. a is a value determined by the amplitude A, the wavelength of the radio wave before reflection, the distance L, and the like.

  Comparing Equation (1) and Equation (2), the frequency f1r of the radio wave R1d (t) shown in Equation (2) is f1 × (2 × vd / c) to the frequency f1 of the radio wave T1 (t). The added frequency.

  That is, the higher the speed vd, the higher the frequency of the reflected radio wave. When the object Y moves away from the radio wave radiation source, that is, when vd is negative, the frequency of the radio wave after reflection is lower than the frequency of the radio wave before reflection.

  Referring to FIG. 4 again, for example, the storage unit 36 preliminarily detects the frequency of the sensing radio wave radiated by the wireless device 12, that is, the frequency of the sensing radio wave before being reflected by the vehicle 10 (hereinafter also referred to as the pre-reflection frequency). Is stored).

  The vehicle information creation unit 33 acquires the pre-reflection frequency from the storage unit 36 via the management unit 35.

  The vehicle information creation unit 33 measures the reception level of the sensing radio wave received by the antenna 31. Then, the vehicle information creation unit 33 performs, for example, FFT (Fast Fourier Transform) on the measurement result to obtain a frequency component included in the sensing radio wave.

  The vehicle information creation unit 33 acquires the frequency of the sensing radio wave after reflection from the FFT result. Specifically, for example, the vehicle information creation unit 33 uses the frequency component having the highest level as the frequency component of the sensing radio wave after reflection, excluding the frequency component of the pre-reflection frequency among the frequency components indicated by the FFT result. , Get the frequency.

  The vehicle information creation unit 33 calculates the speed of the vehicle 10 using the frequency of the sensing radio wave before reflection and the frequency of the sensing radio wave after reflection.

  The vehicle information creation unit 33 creates speed information indicating the speed of the vehicle 10 and sends it to the management unit 35. The management unit 35 stores speed information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Fifth embodiment>
The present embodiment relates to a vehicle sensing system that differs in speed calculation method from the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  In the vehicle sensing system 105 according to the fifth embodiment of the present invention, the wireless device 12 changes the frequency of the sensing radio wave radiated via the antenna 13. The vehicle detector 11 obtains the speed of the vehicle 10 based on a change in reception level for each frequency of the received sensing radio wave.

  For example, the radio device 12 alternately emits sensing radio waves having different frequencies. Let f1 and f2 be the two frequencies of the sensing radio wave radiated by the wireless device 12. Further, it is assumed that the frequency f1 is lower than the frequency f2.

Here, the decrease in the reception level of the diffracted wave is caused by the generation of diffraction loss. If the diffraction loss is J (u), the diffraction loss J (u) is expressed by the following equation.
J (u) = 6.9 + 20 log (sqrt ((u−0.1) 2 + 1) + u−0.1)

  In the above equation, u is a variable proportional to the square root of the frequency of radio waves. The unit of J (u) is dB. The diffraction loss increases as the frequency of radio waves increases.

  FIG. 10 shows the relationship between the frequency of the sensing radio wave and the distance L shown in FIG. 2 when the reception level of the sensing radio wave reaches a predetermined value in the vehicle sensing system according to the fifth embodiment of the present invention. FIG.

  Referring to FIG. 10, when the frequency of the sensing radio wave is fn, the reception level of the sensing radio wave received by vehicle detector 11 when L = Ln becomes a predetermined value. The distance L at which the reception level of the sensing radio wave becomes a predetermined value becomes longer as the frequency of the sensing radio wave decreases. When the frequency of the sensing radio wave is fm, L = Lm.

  That is, the sensing radio wave is more difficult to diffract as the frequency is higher, and is easier to diffract as the frequency is lower.

  Hereinafter, the sensing radio wave of frequency f1 is also referred to as sensing radio wave F1, and the sensing radio wave of frequency f2 is also referred to as sensing radio wave F2.

  FIG. 11 is a diagram showing an example of the relationship between the distance L shown in FIG. 2 and the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the fifth embodiment of the present invention.

  Referring to FIG. 11, the horizontal axis of graphs G <b> 1 and G <b> 2 indicates distance L, and the vertical axis indicates the reception level of sensing radio waves received by vehicle detector 11. The graph G1 shows the change over time of the reception level of the sensing radio wave F1 received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11. A graph G2 shows a change over time of the reception level of the sensing radio wave F2 received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11.

  Referring to graph G1, the reception level of sensing radio wave F1 is level Sh when vehicle 10 is not blocking direct waves from radio device 12.

  The reception level of the sensing radio wave F1 starts to decrease from the position of L = 0 where the direct wave from the radio device 12 is blocked by the vehicle 10, reaches a level Sb1 at a distance L13, and becomes constant. The level Sb1 is a measurement lower limit of the reception level of the sensing radio wave F1 by the vehicle detector 11.

  The reception level of the sensing radio wave F1 starts to rise from the distance L14, and becomes level Sh at the distance L16 where the vehicle detector 11 starts receiving the direct wave from the radio device 12 again.

  Referring to graph G2, the reception level of sensing radio wave F2 is level Sh when vehicle 10 is not blocking direct waves from radio device 12.

  The reception level of the sensing radio wave F2 starts to decrease from the position of L = 0 where the direct wave from the wireless device 12 is blocked by the vehicle 10, reaches the level Sb1 at the distance L11, and reaches the level Sb2 at the distance L12. Constant. The level Sb2 is a lower limit of measurement of the reception level of the sensing radio wave F2 by the vehicle detector 11.

  Then, the reception level of the sensing radio wave F2 starts to rise from the distance L15, and becomes the level Sh at the distance L16 at which the vehicle detector 11 begins to receive the direct wave from the wireless device 12 again.

  Since the frequency f2 is higher than the frequency f1, the sensing radio wave F2 is less diffracted than the sensing radio wave F1. Therefore, the reception level of the sensing radio wave F2 rapidly decreases as compared with the reception level of the sensing radio wave F1, and reaches the level Sb1 at time t22 when L = L11.

  On the other hand, the reception level of the sensing radio wave F1 reaches the level Sb1 at time t11 when L = L13. The vehicle detector 11 obtains the speed of the vehicle 10 using the difference between the time t11 and the time t22.

  FIG. 4 also shows the configuration of the vehicle detector according to the fifth embodiment of the present invention.

  Referring to FIG. 4, storage unit 36 stores, for example, distance L11 and distance L13 obtained by an experiment performed in advance.

  The vehicle information creation unit 33 alternately measures the reception level of the sensing radio wave F1 and the reception level of the sensing radio wave F2 in synchronization with the switching of the sensing radio wave F1 and the sensing radio wave F2 by the wireless device 12. . And vehicle information creation part 33 acquires time t11 and time t22 from a measurement result. Further, the vehicle information creation unit 33 acquires the distance L11 and the distance L13 from the storage unit 36 via the management unit 35.

  Then, the vehicle information creation unit 33 obtains the speed of the vehicle 10 based on (L13−L11) / (t11−t22), creates speed information indicating the speed of the vehicle 10, and sends the speed information to the management unit 35.

  The management unit 35 stores speed information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Note that the wireless device 12 is not limited to switching the frequency of the sensing radio wave, and may be configured to radiate one sensing radio wave including different frequency components.

  When the wireless device 12 radiates one sensing radio wave including different frequency components, the vehicle information creation unit 33 in the vehicle detector 11 uses the antenna 31 to measure the reception level of the sensing radio wave. And the vehicle information preparation part 33 may perform FFT with respect to a measurement result, for example, and may calculate the reception level for every frequency component which the said electromagnetic wave for a sensing contains.

  The wireless device 12 is not limited to the configuration in which the frequency of the sensing radio wave is alternately switched between the two frequencies, and may be configured to repeatedly sweep the frequency between the two frequencies.

  When the radio device 12 repeatedly sweeps the frequency between the two frequencies, the vehicle information creation unit 33 in the vehicle sensor 11 measures, for example, each reception level at three or more frequencies, and uses the measurement result to Ten speeds can be calculated. Thereby, the vehicle information creation unit 33 can calculate the speed of the vehicle 10 with higher accuracy.

  Further, the vehicle information creation unit 33 obtains the relationship between the time and the reception level as shown in FIG. 3, for example, using the highest frequency sensing radio wave in the frequency range to be swept. The difference between the time when the reception level of the sensing radio wave becomes equal to or lower than the predetermined value and the time when the reception level of the radio wave for sensing becomes equal to or higher than the predetermined value after the level becomes lower than the predetermined value (hereinafter also referred to as a level decrease period). The vehicle length of the vehicle 10 is calculated using.

Specifically, when the calculated speed of the vehicle 10 is Vc, the level reduction period is Tu, and the vehicle length of the vehicle 10 is D, the vehicle information creation unit 33 calculates the vehicle length D according to the following equation.
D = Vc × Tu

  The vehicle information creation unit 33 creates vehicle length information indicating the calculated vehicle length D and sends it to the management unit 35. The management unit 35 stores vehicle length information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Sixth Embodiment>
This embodiment relates to a vehicle detection system that uses a radio wave received by a vehicle detector from a device other than a radio as a detection radio wave, as compared with the vehicle detection system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  In the vehicle sensing system 106 according to the fifth embodiment of the present invention, the vehicle sensor 11 transmits radio waves to communicate with other radios other than the vehicle sensor 11, for example, an existing transmitter ( Hereinafter, a radio wave transmitted from an existing radio device) is used as a sensing radio wave.

  The existing radio is, for example, a quasi-zenith satellite transmitter, a GPS transmitter, a mobile phone base station transmitter, a broadcast transmitter, or a low-power radio.

  FIG. 12 is a diagram illustrating reception of radio waves for detection by the vehicle detector in the vehicle detection system according to the sixth embodiment of the present invention.

  Referring to FIG. 12, the vehicle 10 is traveling above the vehicle detector 11. The vehicle detector 11 is radiated from the wireless device 12 through the antenna 13, is detected from the end of the vehicle 10, and is emitted from the existing wireless device 15 to the end of the vehicle 10. The radio waves for sensing that have traveled downward from the vehicle 10 to the vehicle 10 are received.

  12 indicates a corresponding position of the front end of the vehicle 10 on the road surface, for example, a point just below the front end of the vehicle 10 on the road surface, and a corresponding position of the antenna of the vehicle detector 11 on the road surface, for example, the vehicle detector 11 on the road surface. Indicates the distance to the point directly above the antenna.

  Hereinafter, the sensing radio wave radiated from the wireless device 12 is also referred to as a sensing radio wave P1, and the sensing radio wave radiated from the existing radio device 15 is also referred to as a sensing radio wave P2. Further, the frequency of the sensing radio wave P1 is f1, and the frequency of the sensing radio wave P2 is f2. Further, it is assumed that the frequency f1 is lower than the frequency f2.

  FIG. 11 also shows the relationship between the distance L shown in FIG. 12 and the reception level of the sensing radio wave received by the vehicle detector 11 in the vehicle sensing system according to the sixth embodiment of the present invention.

  Referring to FIG. 11, the horizontal axis of graphs G <b> 1 and G <b> 2 indicates distance L, and the vertical axis indicates the reception level of sensing radio waves received by vehicle detector 11. A graph G1 shows a change with time of reception of the sensing radio wave P1 received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11. A graph G2 shows a temporal change in the reception level of the sensing radio wave P2 received by the vehicle detector 11 when the vehicle 10 passes above the vehicle detector 11.

  Referring to graph G1, the reception level of sensing radio wave P1 is level Sh when vehicle 10 is not blocking direct waves from radio device 12.

  Then, the reception level of the sensing radio wave P1 starts to decrease from the position where, for example, L = 0 when the direct wave from the radio 12 is blocked by the vehicle 10, reaches a level Sb1 at a distance L13, and becomes constant. Level Sb1 is a lower limit of measurement of the reception level of the radio wave P1 for detection by the vehicle detector 11.

  Then, the reception level of the sensing radio wave P1 starts to rise from the distance L14, and returns to the level Sh at the distance L16 where the vehicle detector 11 starts receiving the direct wave from the radio device 12 again.

  Referring to graph G2, the reception level of sensing radio wave P2 is level Sh when vehicle 10 is not blocking direct waves from existing radio equipment 15. Then, the reception level of the sensing radio wave P2 starts to decrease from the position where L = 0, for example, the direct wave from the existing radio 15 is blocked by the vehicle 10, becomes level Sb1 at L11, and reaches level Sb2 at distance L12. It reaches and becomes constant. The level Sb2 is a lower limit of measurement of the reception level of the sensing radio wave P2 by the vehicle detector 11. Then, the reception level of the sensing radio wave P2 starts to rise from the distance L15, and the vehicle detector 11 starts receiving the direct wave from the existing radio 15 again. For example, the level returns to the level Sh at the distance L16.

  Since the frequency f2 is higher than the frequency f1, the sensing radio wave P2 is less diffracted than the sensing radio wave P1. Therefore, the reception level of the sensing radio wave P2 is drastically reduced as compared with the reception level of the sensing radio wave P1, and reaches the level Sb1 at time t22 when L = L11.

  On the other hand, the reception level of the sensing radio wave P1 reaches the level Sb1 at time t11 when L = L13. The vehicle detector 11 obtains the speed of the vehicle 10 using the difference between the time t11 and the time t22.

  FIG. 4 also shows the configuration of the vehicle detector according to the sixth embodiment of the present invention.

  Referring to FIG. 4, storage unit 36 stores, for example, distance L11 and distance L22 obtained by an experiment performed in advance.

  The vehicle information creation unit 33 uses the antenna 31 to measure the reception levels of the sensing radio wave P1 and the sensing radio wave P2.

  Specifically, for example, the vehicle information creation unit 33 measures the sensing radio wave received by the antenna 31 for a predetermined period, performs FFT on the measurement result, and detects the sensing radio wave P1 and the sensing radio wave for the predetermined period. The reception level of the radio wave P2 is calculated.

  In addition, the vehicle information creation unit 33 acquires time t11 and time t22 from the temporal change in the reception level of the sensing radio wave P1 and the reception level of the sensing radio wave P2 obtained by performing FFT.

  Further, the vehicle information creation unit 33 acquires the distance L11 and the distance L22 from the storage unit 36 via the management unit 35.

  Then, the vehicle information creation unit 33 obtains the speed of the vehicle 10 based on (L11−L22) / (t11−t22), creates speed information indicating the speed of the vehicle 10, and sends the speed information to the management unit 35.

  The management unit 35 stores speed information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  When there is a change in the position of the existing wireless device 15 or the state of the radio wave from the existing wireless device 15, the wireless device 12 transmits change information that is information indicating the content of the change to the vehicle detector 11. May be.

  Based on the change information received from the wireless device 12, the vehicle detector 11 updates firmware used to create vehicle information, for example, and creates vehicle information using the updated firmware.

  In addition, when there is a change in the position of the existing wireless device 15 or the state of the radio wave from the existing wireless device 15, the wireless device 12 generates vehicle information by the vehicle detector 11 created based on the content of the change. New firmware used for creation may be transmitted to the vehicle detector 11.

  For example, when a new firmware is received from the wireless device 12, the vehicle sensor 11 updates its own firmware with the new firmware, and creates vehicle information using the updated firmware.

  As described above, in the vehicle sensing system according to the sixth embodiment of the present invention, the sensing radio wave is an existing radio that transmits the sensing radio wave to communicate with other radios other than the vehicle detector 11. This is a sensing radio wave transmitted from the machine.

  With such a configuration, vehicle information can be created using sensing radio waves transmitted by existing equipment, so compared to the case of newly installing a device for transmitting vehicle sensing radio waves, The introduction cost of the vehicle sensing system including the vehicle sensor 11 can be reduced.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Seventh embodiment>
The present embodiment further relates to a vehicle sensing system that determines the traveling direction of the vehicle 10 as compared to the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 13 is a diagram showing a configuration of a vehicle sensing system according to the seventh embodiment of the present invention.

  Referring to FIG. 13, the vehicle sensing system 107 includes a vehicle sensor 11, a radio device 12, and two antennas 13. The wireless device 12 radiates sensing radio waves having different frequencies from the two antennas 13.

  In FIG. 13, the antenna 13 close to the vehicle 10 is an antenna 13N, and the antenna 13 far from the vehicle 10 is an antenna 13F. Further, the sensing radio wave radiated from the antenna 13N is defined as a sensing radio wave N, and the sensing radio wave radiated from the antenna 13F is defined as a sensing radio wave N.

  When the vehicle 10 passes above the vehicle sensor 11, the direct wave from the antenna 13N to the vehicle sensor 11 and the direct wave from the antenna 13F to the vehicle sensor 11 are transmitted from the antenna 13N to the vehicle sensor 11. The direct wave which goes is cut off first. Therefore, in the vehicle detector 11, the reception level of the sensing radio wave N decreases before the reception level of the sensing radio wave F.

  The vehicle detector 11 determines which of the reception levels of the detection radio wave N and the reception level of the detection radio wave F has been reduced first, and based on the determination result, the traveling direction of the vehicle 10 Judging.

  FIG. 4 also shows the configuration of the vehicle sensor according to the first embodiment of the present invention.

  Referring to FIG. 4, vehicle information creation unit 33 uses antenna 31 to measure the reception levels of sensing radio wave N and sensing radio wave F.

  Specifically, for example, the vehicle information creation unit 33 measures the reception level of the sensing radio wave received by the antenna 31, performs FFT on the measurement result, and receives the sensing radio wave N from the FFT result. The level and the reception level of the sensing radio wave F are obtained.

  The vehicle information creation unit 33 then detects the reception level of the sensing radio wave N and the reception level of the sensing radio wave F from the temporal change in the reception level of the sensing radio wave N and the reception level of the sensing radio wave F obtained by performing FFT. Of these, the traveling direction of the vehicle 10 is determined based on which reception level has fallen first.

  The vehicle information creation unit 33 creates direction information indicating the determined traveling direction of the vehicle 10 and sends the created direction information to the management unit 35.

  The management unit 35 stores direction information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  The wireless device 12 is not limited to the configuration in which the sensing radio wave N and the sensing radio wave F having different frequencies are radiated at the same time, and the radio device 12 has a configuration in which the sensing radio wave N and the sensing radio wave F having the same frequency are alternately switched and radiated. May be.

  When the radio device 12 alternately emits the sensing radio wave N and the sensing radio wave F having the same frequency, the vehicle information creation unit 33 in the vehicle detector 11 is synchronized with the sensing radio wave switching by the radio device 12. Thus, the measurement of the reception level of the sensing radio wave N and the measurement of the reception level of the sensing radio wave F are alternately performed.

  Then, the vehicle information creation unit 33 receives any of the reception level of the sensing radio wave N and the reception level of the sensing radio wave F from the temporal change in the reception level of the sensing radio wave N and the reception level of the sensing radio wave F. Based on whether the level has dropped first, the traveling direction of the vehicle 10 is determined.

  As described above, in the vehicle sensing system according to the seventh embodiment of the present invention, the antenna 31 receives the sensing radio wave N and the sensing radio wave F transmitted from the wireless device 12. The vehicle information creation unit 33 measures the sensing radio wave N and the sensing radio wave F received by the antenna 31, and creates vehicle information related to the vehicle 10 based on a change in the measurement result. The antenna 31 is embedded under the road surface on which the vehicle 10 passes or under the road surface on which the vehicle 10 stops, or on the road surface on which the vehicle 10 passes or on the road surface on which the vehicle 10 stops.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using radio waves. Further, from the change in values obtained by measuring the sensing radio wave N and the sensing radio wave F, for example, not only information on whether the vehicle 10 exists above the vehicle detector 11 but also the speed of the vehicle 10. In addition, since it is possible to acquire information such as a vehicle type or a traveling direction, it is possible to easily grasp a detailed traffic situation.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Eighth Embodiment>
The present embodiment further relates to a vehicle sensing system that determines the traveling direction of the vehicle 10 as compared to the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 14 is a diagram showing a configuration of a vehicle sensing system according to the eighth embodiment of the present invention.

  Referring to FIG. 14, the vehicle sensing system 108 includes a vehicle sensor 11, a radio device 12, and an antenna 13. The antenna 13 is installed at a position away from the vehicle detector 11 in an oblique direction.

  In FIG. 14, the vehicle 10 close to the vehicle detector 11 and far from the antenna 13 is defined as a vehicle 10I, and the traveling direction of the vehicle 10I is indicated by an arrow 70I. Further, the vehicle 10 close to the antenna 13 and far from the vehicle detector 11 is defined as a vehicle 10J, and the traveling direction of the vehicle 10J is indicated by an arrow 70J.

  The vehicle detector 11 measures the reception level of the sensing radio wave radiated from the antenna 13. For example, when the vehicle 10I or the vehicle 10J cuts off the direct wave from the antenna 13, the reception level of the sensing radio wave received by the vehicle detector 11 decreases.

  Further, the vehicle sensor 11 measures the level of the magnetic field in the vehicle sensor 11. For example, when the vehicle 10I or the vehicle 10J approaches the vehicle detector 11, the magnetic field level in the vehicle detector 11 increases.

  When the vehicle 10I travels in the direction of the arrow 70I and passes above the vehicle detector 11, first, the vehicle 10I approaches the vehicle detector 11, so that the magnetic field level in the vehicle detector 11 increases. Then, after that, the vehicle 10I blocks the direct wave from the antenna 13, whereby the reception level of the sensing radio wave received by the vehicle detector 11 is lowered.

  On the other hand, when the vehicle 10J travels in the direction of the arrow 70J and passes above the vehicle detector 11, the vehicle 10J first receives a detection received by the vehicle detector 11 by blocking the direct wave from the antenna 13. The reception level of radio waves decreases. Thereafter, when the vehicle 10J further approaches the vehicle detector 11, the level of the magnetic field in the vehicle detector 11 increases.

  The vehicle sensor 11 measures the reception level and the magnetic field level, and determines the traveling direction of the vehicle 10 based on which of the reception level and the magnetic field level changes first.

  FIG. 15 shows an example of a temporal change in the reception level of the sensing radio wave received by the vehicle detector and a temporal change in the magnetic field level in the vehicle detector in the vehicle sensing system according to the eighth embodiment of the present invention. FIG.

  Referring to FIG. 15, the horizontal axis of graph G <b> 1 indicates time, and the vertical axis indicates the reception level of the sensing radio wave received by vehicle detector 11. A graph G1 shows a change over time of the reception level of the sensing radio wave received by the vehicle detector 11 when the vehicle 10I shown in FIG. 14 travels in the direction of the arrow 70I and passes above the vehicle detector 11. ing.

  In addition, the horizontal axis of the graph G2 indicates time, and the vertical axis indicates the magnetic field level in the vehicle detector 11. The graph G2 shows the time change of the magnetic field level in the vehicle detector 11 when the vehicle 10I shown in FIG. 14 travels in the direction of the arrow 70I and passes over the vehicle detector 11.

  The graph G1 and the graph G2 respectively show the reception level of the sensing radio wave and the magnetic field level during the same period.

  Referring to graph G1, the reception level of the sensing radio wave is Sh when vehicle 10 is not blocking the direct wave from wireless device 12. The reception level of the sensing radio wave starts to decrease from time t10 when the direct wave from the radio 12 is blocked by the vehicle 10, reaches a level Sb at time t11, and becomes constant. The level Sb is a measurement lower limit of the reception level by the vehicle detector 11. Then, the reception level of the sensing radio wave starts to rise from time t12, and returns to level Sh at time t13 when the vehicle detector 11 starts receiving the direct wave from the radio device 12 again.

  Sd indicates a predetermined threshold value set between the level Sh and the level Sb. Also, ts indicates the time when the reception level has fallen from the level Sh and has reached the same level as the threshold value Sd.

  Referring to graph G2, the level of the magnetic field is Hh when vehicle 10 is sufficiently away from vehicle detector 11. Then, the magnetic field level starts to increase from time t20 due to the approach of the vehicle 10, reaches Ht at time t21, and starts to decrease. Then, after becoming Hb at time t22, it rises and returns to Hh at time t23.

  Hd represents a predetermined threshold value set between the level Hh and the level Ht. Further, th indicates the time when the magnetic field level rises from Hh and reaches the same level as the threshold value Hd.

  Here, when the time ts is compared with the time th, the time th is earlier than the time ts.

  When the vehicle 10I travels in the direction of the arrow 70I and passes above the vehicle detector 11, the time th is earlier than the time ts.

  FIG. 16 shows another example of the temporal change in the reception level of the sensing radio wave received by the vehicle detector and the temporal change in the magnetic field level in the vehicle detector in the vehicle sensing system according to the eighth embodiment of the present invention. FIG.

  Referring to FIG. 16, the horizontal axis of graph G3 indicates time, and the vertical axis indicates the reception level of the sensing radio wave received by vehicle detector 11. A graph G3 shows a change over time of the reception level of the sensing radio wave received by the vehicle detector 11 when the vehicle 10J shown in FIG. 14 travels in the direction of the arrow 70J and passes above the vehicle detector 11. ing.

  Further, the horizontal axis of the graph G4 indicates time, and the vertical axis indicates the magnetic field level in the vehicle detector 11. A graph G4 shows a temporal change in the level of the magnetic field in the vehicle detector 11 when the vehicle 10J shown in FIG. 14 travels in the direction of the arrow 70J and passes over the vehicle detector 11.

  The graph G3 and the graph G4 respectively show the reception level of the sensing radio wave and the magnetic field level during the same period.

  In FIG. 16, the time ts is earlier than the time th as compared with FIG.

  When the vehicle 10J travels in the direction of the arrow 70J and passes above the vehicle detector 11, the time ts is earlier than the time th.

  FIG. 17 is a diagram showing a configuration of a vehicle sensor according to the eighth embodiment of the present invention.

  Referring to FIG. 17, the magnetic sensor 38 measures the level of the magnetic field in the vehicle sensor 11 and sends the measurement result to the vehicle information creation unit 33.

  The vehicle information creation unit 33 acquires the time ts shown in FIG. 15 or 16 from the measurement result of the magnetic field level received from the magnetic sensor 38.

  Further, the vehicle information creation unit 33 acquires the time th shown in FIG. 15 or 16 from the measurement result of the reception level of the sensing radio wave measured using the antenna 31.

  Then, the vehicle information creation unit 33 compares the acquired time ts with the time th, and when the time th is earlier than the time ts, the vehicle 10 moves the road 14 in the direction of the arrow 70I. It is determined that the vehicle has traveled. Further, when the time ts is earlier than the time th, it is determined that the vehicle 10 has traveled on the road 14 in the direction of the arrow 70J.

  The vehicle information creation unit 33 creates direction information indicating the traveling direction of the vehicle 10 from the determination result of the traveling direction of the vehicle 10 and sends the created direction information to the management unit 35.

  The management unit 35 stores direction information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Ninth embodiment>
The present embodiment relates to a vehicle sensing system in which a method for calculating the speed of the vehicle 10 is different from that of the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 18 is a diagram showing magnetic field measurement in the vehicle sensing system according to the ninth embodiment of the present invention.

  Referring to FIG. 18, vehicle 10 includes a strong magnetic field unit 16 that generates a strong magnetic field. The strong magnetic field unit 16 is, for example, a dynamo that the vehicle 10 generally includes.

  18 indicates a corresponding position of the front end of the vehicle 10 on the road surface, for example, a point immediately below the front end of the vehicle 10 on the road surface, and a corresponding position of the antenna of the vehicle detector 11 on the road surface, for example, the vehicle detector 11 on the road surface. Indicates the distance to the point directly above the antenna. L1 indicates the distance between the front end of the vehicle 10 and the strong magnetic field part 16, for example.

  When the strong magnetic field unit 16 is located immediately above the vehicle sensor 11, that is, for example, when L = L1, the level of the magnetic field in the vehicle sensor 11 is the strongest.

  FIG. 19 is a diagram showing the relationship between the distance L shown in FIG. 18 and the magnetic field level in the vehicle detector in the vehicle sensing system according to the ninth embodiment of the present invention.

  Referring to FIG. 19, the horizontal axis of the graph indicates the distance L, and the vertical axis indicates the level of the magnetic field in the vehicle detector 11. The graph shows the level of the magnetic field in the vehicle sensor 11 when the vehicle 10 passes over the vehicle sensor 11.

  The level of the magnetic field in the vehicle detector 11 is level Hh when the vehicle 10 is sufficiently away from the vehicle detector 11. The magnetic field level starts to rise from the position of L = 0, for example, when the vehicle 10 approaches. The magnetic field level reaches a level Ht at a distance L1 where the strong magnetic field portion 16 is located directly above the vehicle detector 11, reaches a constant level, and begins to decrease from the distance L2. Then, the level of the magnetic field reaches the level Hb at the distance L3 and becomes constant, starts increasing from L4, and returns to the level Hh at L5.

  Hereinafter, the period from time t0 when L = 0 to time t1 when L = L1 is also referred to as a rise time of the magnetic field level.

  The vehicle detector 11 calculates the speed of the vehicle 10 based on the rise time of the magnetic field level.

  FIG. 17 also shows the configuration of the vehicle sensor according to the ninth embodiment of the present invention.

  Referring to FIG. 17, storage unit 36 stores in advance a distance L1 for each vehicle type, for example. The magnetic sensor 38 measures the level of the magnetic field in the vehicle detector 11 and sends the measurement result to the vehicle information creation unit 33.

  The vehicle information creation unit 33 acquires the times t0 and t1 shown in FIG. 19 from the measurement result of the magnetic field level received from the magnetic sensor 38.

Moreover, the vehicle information creation part 33 acquires the vehicle type information of the vehicle 10 by the process similar to 1st Embodiment or 4th Embodiment, for example, and memorize | stores the distance L1 according to the vehicle type which the acquired vehicle type information shows Obtained from the unit 36. Here, assuming that the speed of the vehicle 10 is Vm, the vehicle information creation unit 33 calculates the speed Vm according to the following equation.
Vm = L1 / (t1-t0)

  The vehicle information creation unit 33 creates speed information indicating the speed Vm and sends the created speed information to the management unit 35.

  The management unit 35 stores speed information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Tenth Embodiment>
The present embodiment relates to a vehicle sensing system in which a vehicle detector emits radio waves to detect the speed of the vehicle, as compared to the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  In the vehicle detection system 110 according to the tenth embodiment of the present invention, the vehicle detector 11 radiates radio waves above the road surface of the road 14 in order to obtain the speed of the vehicle 10. Hereinafter, the radio wave radiated by the vehicle detector 11 to obtain the speed of the vehicle 10 is also referred to as a speed detection radio wave.

  FIG. 20 is a diagram showing the reflection of the velocity detection radio wave radiated by the vehicle detector in the vehicle sensing system according to the tenth embodiment of the present invention.

  Referring to FIG. 20, the velocity detection radio wave radiated from vehicle detector 11 is reflected on the front surface portion of vehicle 10 and returns toward vehicle detector 11.

  Since the vehicle 10 is traveling in the direction of the arrow 70, the reflected speed detection radio wave includes a higher frequency component than the speed detection radio wave before reflection due to the Doppler effect.

  The vehicle detector 11 obtains the speed of the vehicle 10 by utilizing the change in the frequency component of the speed detection radio wave due to the Doppler effect.

  FIG. 21 is a diagram showing a configuration of a vehicle detector according to the tenth embodiment of the present invention.

  Referring to FIG. 21, vehicle detector 11 further includes a transmission unit 40 and an antenna 41 as compared with the vehicle detector according to the first embodiment of the present invention.

  The transmission unit 40 transmits an electric signal having a frequency in the RF band to the antenna 41. The antenna 41 converts the electric signal received from the transmission unit 40 into a radio wave, and radiates it as a speed detection radio wave above the road 14. The storage unit 36 stores in advance the frequency of the velocity detection radio wave transmitted from the antenna 41 before reflection, that is, the frequency of the electrical signal transmitted from the transmission unit 40 to the antenna 41.

  The vehicle information creation unit 33 measures the radio wave received by the antenna 31, for example, performs FFT on the measurement result, and acquires the frequency of the velocity detection radio wave after reflection from the FFT result. Specifically, for example, the vehicle information creation unit 33 acquires the above frequency using the highest frequency component of the frequency components indicated by the FFT result as the frequency component of the velocity detection radio wave after reflection.

  Further, the vehicle information creation unit 33 acquires the frequency of the speed detection radio wave before reflection from the storage unit 36 via the management unit 35.

  The vehicle information creation unit 33 calculates the speed of the vehicle 10 by the same processing as that of the fourth embodiment of the present invention, using the frequency of the speed detection radio wave before reflection and the frequency of the speed detection radio wave after reflection. To do. Then, the vehicle information creation unit 33 creates speed information indicating the speed of the vehicle 10 and sends the created speed information to the management unit 35.

  The vehicle information creation unit 33 creates speed information using not only the speed detection radio wave reflected on the front surface of the vehicle 10 but also the speed detection radio wave reflected on the bottom surface part of the vehicle 10 or the rear surface part of the vehicle 10. May be.

  The management unit 35 stores speed information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Eleventh embodiment>
The present embodiment relates to a vehicle sensing system in which the vehicle detector includes a plurality of antennas as compared to the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 22 is a diagram illustrating an example of the arrangement of antennas of the vehicle detector in the vehicle detection system according to the eleventh embodiment of the present invention. FIG. 23 is a diagram showing the configuration of the vehicle detector according to the eleventh embodiment of the present invention.

  Referring to FIGS. 22 and 23, vehicle detector 11 in vehicle detection system 111 further includes antenna 30 as compared with the vehicle detector according to the first embodiment of the present invention. Units other than the antenna 30 and the antenna 31 in the vehicle detector 11 are included in the vehicle detector main body 45.

  The vehicle detector 11 measures the reception level of the sensing radio wave received by each of the antenna 30 and the antenna 31, and compares the measurement results to determine the traveling direction and speed of the vehicle 10, for example.

  The antenna 30 and the antenna 31 are installed apart from each other, and receive a sensing radio wave radiated from the wireless device 12.

  The vehicle information creation unit 33 compares the temporal change in the reception level of the sensing radio wave received by the antenna 30 with the temporal change in the reception level of the sensing radio wave received by the antenna 31.

  Based on the comparison result, the vehicle information creation unit 33 determines which of the direct waves from the antenna 13 to the antenna 30 and the direct waves from the antenna 13 to the antenna 31 has been blocked by the vehicle 10 first. Judging.

  The vehicle information creation unit 33 creates direction information indicating the traveling direction of the vehicle 10 based on the determination result, and sends the direction information to the management unit 35.

  In addition, for example, the vehicle information creation unit 33 calculates the speed of the vehicle 10 from the distance between the antenna 30 and the antenna 31 and the time required for the vehicle 10 to travel between the antenna 30 and the antenna 31.

  Specifically, the storage unit 36 stores a distance (hereinafter also referred to as an inter-antenna distance) between a position where the antenna 30 is installed and a position where the antenna 31 is installed in advance.

  The vehicle information creation unit 33 directly moves from the antenna 13 to the antenna 30 based on the temporal change in the reception level of the sensing radio wave received by the antenna 30 and the temporal change in the reception level of the sensing radio wave received by the antenna 31. A difference between the time when the vehicle 10 cuts off the wave and the time when the vehicle 10 cuts off the direct wave from the antenna 13 toward the antenna 31 (hereinafter also referred to as a cut-off time difference) is obtained.

  Then, the vehicle information creation unit 33 acquires the inter-antenna distance from the storage unit 36 via the management unit 35, and calculates the speed of the vehicle 10 based on the inter-antenna distance and the cutoff time difference.

  The vehicle information creation unit 33 creates speed information indicating the speed of the vehicle 10 from the calculation result, and sends the created speed information to the management unit 35.

  The management unit 35 stores the direction information and speed information, which are vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  The vehicle detector 11 is not limited to the configuration in which the antenna 30 and the antenna 31 are installed apart from each other, but may be configured to install the antenna 30 and the antenna 31 in different directions.

  Specifically, for example, the vehicle detector 11 includes the antenna 30 and the antenna 31 having directivity, and the direction of the main lobe of the antenna 30 and the direction of the main lobe of the antenna 31 are Install differently.

  FIG. 24 is a diagram showing another example of the antenna arrangement of the vehicle detector in the vehicle detection system according to the eleventh embodiment of the present invention.

  Referring to FIG. 24, antenna 30 and antenna 31 provided in vehicle detector 11 are embedded under the road surface of road 14. In addition, the antenna 30 and the antenna 31 are installed so that their main lobes are in different directions. The direction of the main lobe of the antenna 30 is indicated by an arrow 80, and the direction of the main lobe of the antenna 31 is indicated by an arrow 81.

  The direction of the arrow 80 is along the traveling direction of the vehicle 10, while the direction of the arrow 81 is along the opposite direction of the traveling direction of the vehicle 10.

  For example, in FIG. 24, when vehicle 10 travels in the direction of arrow 70, reception is performed by antenna 31 among the reception level of the sensing radio wave received by antenna 30 and the reception level of the sensing radio wave received by antenna 31. The reception level of the detected radio wave is lowered first.

  Referring to FIG. 23 again, vehicle information creation unit 33 determines which reception level is the first of the reception level of the sensing radio wave received by antenna 30 and the reception level of the sensing radio wave received by antenna 31. The traveling direction of the vehicle 10 is determined based on whether or not the vehicle 10 is lowered.

  The vehicle information creation unit 33 creates direction information indicating the traveling direction of the vehicle 10 based on the determination result, and sends the direction information to the management unit 35.

  Further, the vehicle information creation unit 33 is based on, for example, the difference between the time when the reception level of the sensing radio wave received by the antenna 30 decreases and the time when the reception level of the sensing radio wave received by the antenna 31 decreases. To calculate the speed of the vehicle 10. Then, the vehicle 10 creates speed information indicating the calculated speed of the vehicle 10 and sends it to the management unit 35.

  The management unit 35 stores the direction information and speed information, which are vehicle information received from the vehicle information creation unit 33, in the storage unit 36.

  The vehicle detector 11 may include all of the antenna 30 and the antenna 31 shown in FIG. 22 and the antenna 30 and the antenna 31 shown in FIG.

  Further, the vehicle detector main body 45 is not limited to the configuration not including the antenna 30 and the antenna 31, and may be configured to include one or both of the antenna 30 and the antenna 31.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Twelfth embodiment>
The present embodiment relates to a vehicle sensing system in which the vehicle detector transmits a vehicle information to a radio device in a different manner compared to the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 25 is a diagram showing a configuration of a vehicle sensing system according to the twelfth embodiment of the present invention.

  Referring to FIG. 25, the vehicle detection system 112 includes a vehicle detector 11, a radio device 12, an antenna 13, and a synchronization processing unit 39.

  The synchronization processing unit 39 performs processing for synchronizing the wireless device 12 and each vehicle detector 11 by transmitting and receiving time information between the wireless device 12 and the plurality of vehicle detectors 11.

  The synchronization processing unit 39 may be included in the vehicle detector 11, may be included in the wireless device 12, or may be a device other than the vehicle detector 11 and the wireless device 12 (hereinafter also referred to as a synchronization device). You may have. In addition, the synchronization processing unit 39 may be included in both the vehicle sensor 11 and the wireless device 12, or may be included in the vehicle sensor 11, the wireless device 12, and the synchronization device.

  Hereinafter, the synchronization processing unit 39 included in the vehicle detector 11 is referred to as a synchronization processing unit 39A, the synchronization processing unit 39 included in the wireless device 12 is referred to as a synchronization processing unit 39B, and the synchronization processing unit 39 included in the synchronization device is also referred to as a synchronization processing unit 39C. .

  For example, when the vehicle detector 11 and the wireless device 12 include the synchronization processing unit 39, the synchronization processing unit 39B in the wireless device 12 creates wireless device time information that is time information indicating the current time according to its own internal clock. It transmits to each vehicle sensor 11.

  The synchronization processing unit 39A in each vehicle sensor 11 corrects the time of the internal clock in its own vehicle sensor 11 based on the radio time information from the radio device 12, and the radio device 12 and its own vehicle sensor. 11 is synchronized.

  Further, for example, when the vehicle detector 11, the radio device 12, and the synchronization device all include the synchronization processing unit 39, the synchronization processing unit 39C in the synchronization device is a synchronization device that is time information indicating the current time by its own internal clock. Time information is created and transmitted to each vehicle sensor 11 and the wireless device 12.

  The synchronization processing unit 39A in each vehicle sensor 11 corrects the time of the internal clock in its own vehicle sensor 11 based on the synchronization device time information from the synchronization device, and the synchronization device and its own vehicle sensor 11 are connected. Synchronize.

  The synchronization processing unit 39B in the wireless device 12 corrects the time of the internal clock in the own wireless device 12 based on the synchronization device time information from the synchronizing device, and synchronizes the synchronizing device and the own wireless device 12. Thereby, each vehicle sensor 11 and the radio device 12 are synchronized with each other.

  Each vehicle detector 11 transmits vehicle information to the radio device 12 at a predetermined time for each vehicle detector 11.

  Based on the time when the vehicle information is received, the wireless device 12 recognizes the vehicle detector 11 that is the transmission source of the vehicle information. Since the vehicle sensor 11 and the wireless device 12 are synchronized, the wireless device 12 can accurately recognize the vehicle sensor 11 that is the transmission source of the vehicle information.

  In addition, the synchronization processing unit 39 in the device on the time information transmission side periodically creates and transmits time information, for example. For example, the synchronization processing unit 39 in the time information receiving side device stops operating except the time zone in which the receiving side device receives the time information, and in the time zone in which the receiving side device receives the time information. Resume operation. Thus, power consumption in the receiving device can be suppressed.

  The synchronization processing unit 39 is not limited to a configuration that synchronizes the time of the wireless device 12 and each vehicle detector 11, but may be a configuration that adjusts the elapsed time from the reference time, such as frame synchronization.

  In addition, the vehicle detection system 112 is not limited to a configuration in which one radio device 12 is installed for one vehicle sensor 11, and a configuration in which one radio device 12 is installed for a plurality of vehicle sensors 11. It may be.

  In this case, for example, the plurality of vehicle detectors 11 are installed several meters away from each other along the traveling direction of the vehicle 10.

  The vehicle information creation unit 33 in each vehicle sensor 11 passes the vehicle 10 above the own vehicle sensor 11 based on the measurement result of the sensing radio wave received by the antenna 31 in the own vehicle sensor 11. Each time, time information indicating the time when the vehicle 10 passed and the period during which the vehicle 10 existed above the vehicle detector 11 is created. Then, the vehicle information creation unit 33 sends the created existence time information to the management unit 35.

  The management unit 35 stores the existence time information, which is vehicle information received from the vehicle information creation unit 33, in the storage unit 36. Then, the management unit 35 acquires all the existing time information stored in the storage unit 36, for example, at an interval of 1 minute, and transmits the acquired existing time information to the wireless device 12 via the communication unit 32. Further, the management unit 35 deletes the existing time information transmitted to the wireless device 12 from the storage unit 36.

  The wireless device 12 confirms the existence time information received every minute from each vehicle sensor 11 and associates each existence time information related to the same vehicle 10 with each other. And the radio | wireless machine 12 calculates | requires the speed and vehicle type of each vehicle 10 using each presence time information linked | related with each other.

  Specifically, for example, the wireless device 12 obtains the speed of the specific vehicle 10 from the time indicated by each existence time information associated with each other. Further, the wireless device 12 obtains the vehicle length of the vehicle 10 from the speed and the period indicated by the existence time information, and determines the vehicle type of the vehicle 10 based on the vehicle length.

  Further, the wireless device 12 obtains comprehensive vehicle information, that is, an average speed of the vehicle 10 per minute and the number of vehicle types, for example, from the speed and vehicle type of each vehicle 10.

  The vehicle information creation unit 33 is not limited to the configuration for creating the existence time information every time the vehicle 10 passes above the own vehicle sensor 11, but the own vehicle sensor 11 starting from a specific time. Alternatively, information that alternately indicates a period in which the vehicle 10 exists and a period in which the vehicle 10 does not exist may be generated and transmitted to the wireless device 12.

  In this case, the wireless device 12 obtains the speed and the vehicle type of each vehicle 10 based on the information transmitted from each vehicle detector 11, and from the speed and the vehicle type of each vehicle 10, for example, the vehicle 10 of every minute. Find the average speed and number of cars.

  As described above, in the vehicle detection system according to the twelfth embodiment of the present invention, the synchronization processing unit 39 transmits and receives time information between the wireless device 12 and each vehicle detector 11, The process which synchronizes each vehicle sensor 11 is performed.

  With such a configuration, for example, each vehicle detector 11 transmits vehicle information at a time determined for each vehicle detector 11, thereby transmitting vehicle information at a different timing from the other vehicle detectors 11. Therefore, it is possible to avoid collision of sensing radio waves transmitted by each vehicle detector 11. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of vehicle information can be reduced and consumption of electric power can be suppressed. Further, when the vehicle detection system includes a plurality of vehicle detectors 11, more accurate vehicle information can be obtained using the measurement results of the sensing radio waves in the vehicle detectors 11 synchronized with each other.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.
<Thirteenth embodiment>

  The present embodiment relates to a vehicle sensing system in which a vehicle detector is installed above the road surface as compared with the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

  FIG. 26 is a diagram showing a configuration of a vehicle sensing system according to the thirteenth embodiment of the present invention.

  With reference to FIG. 26, the vehicle sensing system 113 includes a vehicle sensor 21 and a transmission device 22. The vehicle detector 21 includes an antenna (measurement antenna) 51 and a vehicle detector main body 57.

  For example, the transmission device 22 is embedded under the road surface of the road 14 and radiates upward from below the road surface of the road 14.

  The vehicle detector 21 is installed at a position higher than the road surface of the road 14, for example. The vehicle detector 21 measures the radio wave received by the antenna 51 and detects the vehicle 10 passing through the road 14 based on the change in the measurement result.

  Hereinafter, the radio wave radiated from the transmission device 22 and used for the vehicle detector 21 to detect the vehicle 10 is also referred to as a sensing radio wave.

  FIG. 27 is a diagram illustrating reception of sensing radio waves by the vehicle detector in the vehicle sensing system according to the thirteenth embodiment of the present invention.

  Referring to FIG. 27, vehicle 10 is traveling above transmission device 22, and a part of vehicle 10 is located on a straight line connecting antenna of transmission device 22 and antenna 51.

  The sensing radio wave radiated from the transmission device 22 and traveling straight to the antenna 51 is blocked by the vehicle 10 and therefore does not reach the vehicle detector 21. However, a part of the sensing radio wave radiated from the transmission device 22 goes around the vehicle 10 from the end of the vehicle 10 and reaches the vehicle detector 21.

  Hereinafter, the sensing radio wave traveling straight to the vehicle detector 21 is also referred to as a direct wave. The sensing radio wave that travels from the end of the vehicle 10 to the upper side of the vehicle 10 is also referred to as a diffracted wave.

  27 indicates a corresponding position of the front end of the vehicle 10 on the road surface, for example, a point on the road surface directly below the front end of the vehicle 10 and a corresponding position of the antenna of the transmission device 22 on the road surface, for example, the true position of the antenna of the transmission device 22. Indicates the distance to a point on the upper road surface.

  For example, the reception level of the sensing radio wave that reaches the vehicle detector 21 by going around the vehicle 10 from the front end of the vehicle 10 decreases as the distance L increases.

  FIG. 3 also shows an example of temporal change in the reception level of the sensing radio wave received by the vehicle detector in the vehicle sensing system according to the thirteenth embodiment of the present invention.

  Referring to FIG. 3, the horizontal axis of the graph indicates time, and the vertical axis indicates the reception level of the sensing radio wave received by the vehicle detector 21. The graph shows the time change of the reception level of the sensing radio wave received by the vehicle detector 21 when the vehicle 10 passes above the transmission device 22.

  The reception level of the sensing radio wave is level Sh when the vehicle 10 is not blocking the direct wave from the transmission device 22.

  The reception level of the sensing radio wave starts to decrease from time t0 when the direct wave from the transmission device 22 is blocked by the vehicle 10, reaches a level Sb at time t1, and becomes constant. The level Sb is a measurement lower limit of the reception level by the vehicle detector 21 and is, for example, a reception level of floor noise.

  The reception level of the sensing radio wave starts to rise from time t2, and returns to level Sh at time t3 when the vehicle detector 21 starts receiving the direct wave from the transmission device 22 again.

  Further, a period Ta from time t0 to time t3, a period Tb from time t0 to time t1, a period Tc from time t1 to time t2, and a period Td from time t2 to time t3 depend on the speed of the vehicle 10. For example, the higher the speed of the vehicle 10, the shorter.

  FIG. 28 is a diagram illustrating the configuration of the transmission apparatus according to the thirteenth embodiment of the present invention.

  Referring to FIG. 28, transmission device 22 includes antenna (road surface side antenna) 71, communication unit 72, sensed radio wave transmission unit 73, sleep control unit 74, management unit 75, storage unit 76, battery, and the like. A unit 77 and a magnetic sensor 78 are provided.

  The transmission device 22 operates using, for example, power stored in a battery. Specifically, the battery unit 77 includes the battery, converts the output of the battery into a predetermined voltage level, and supplies the converted voltage to the entire transmitter 22.

  The transmission device 22 is not limited to the configuration including the battery unit 77, and may be configured not to include the battery unit 77. When the transmission device 22 does not include the battery unit 77, the transmission device 22 receives power supply from, for example, a battery installed outside the transmission device 22.

  The antenna 71 is embedded under the road surface of the road 14 through which the vehicle 10 passes along with other units in the transmission device 22. The antenna 71 is not limited to the road surface of the road 14 through which the vehicle 10 passes, and may be installed on the road surface of the road 14 through which the vehicle 10 passes. Moreover, the antenna 71 may be embedded under the road surface where the vehicle 10 stops, for example, like a parking lot, or may be installed on the road surface where the vehicle 10 stops.

  The sensing radio wave transmission unit 73 transmits a sensing radio wave from the antenna 71 to the vehicle detector 21 by transmitting, for example, an RF band electrical signal to the antenna 71.

  The antenna 71 is also used for communication between the vehicle detector 21 and the transmission device 22. The communication unit 72 communicates with the vehicle detector 21 by transmitting and receiving signals to and from the vehicle detector 21 via the antenna 71. Specifically, the communication unit 72 transmits information received from the management unit 75 to the vehicle detector 21 via the antenna 71, and transmits information received from the vehicle sensor 21 via the antenna 71 to the management unit 75.

  The sleep control unit 74 operates the sensed radio wave transmission unit 73 intermittently. Specifically, for example, when the sleep control unit 74 determines that the vehicle 10 has not passed over the transmission device 22 for a predetermined period based on the reception level of the radio wave received by the antenna 71, the sensed radio wave The operation of the transmission unit 73 is stopped.

  The sleep control unit 74 restarts the operation of the sensing radio wave transmission unit 73 when the predetermined condition is satisfied after the operation of the sensing radio wave transmission unit 73 is stopped.

  Specifically, for example, the sleep control unit 74 monitors the reception level of the radio wave received by the antenna 71, and detects the approach of the vehicle 10 from the change in the reception level when the reception level changes. Then, the operation of the sensed radio wave transmission unit 73 is resumed.

  Further, for example, most of the vehicle 10 is made of metal, and a strong magnetic field is generated around the dynamo that the vehicle 10 generally has, so that the vehicle 10 approaches the transmission device 22. The magnetic field level or the magnetic field direction in the transmitter 22 changes.

  The magnetic sensor 78 measures the magnetic field level or magnetic field direction in the transmission device 22 and sends the measurement result to the sleep control unit 74.

  The sleep control unit 74 monitors the measurement result of the magnetic field level or magnetic field direction received from the magnetic sensor 78. For example, when there is a change in the measurement result, the sleep control unit 74 detects the approach of the vehicle 10 from the change in the measurement result. The operation of the radio wave transmission unit 73 is resumed.

  The transmission device 22 is not limited to the configuration including the magnetic sensor 78, and may be a configuration not including the magnetic sensor 78, or may be a configuration including a vibration sensor instead of the magnetic sensor 78.

  When the vehicle sensor 21 includes a vibration sensor instead of the magnetic sensor 78, the vibration sensor measures, for example, vibration of the road 14 and sends the measurement result to the sleep control unit 74.

  The sleep control unit 74 monitors the measurement result of the vibration received from the vibration sensor. When there is a change in the measurement result, for example, the sleep control unit 74 detects the approach of the vehicle 10 and restarts the operation of the sensed radio wave transmission unit 73.

  FIG. 29 is a diagram showing a configuration of a vehicle detector according to the thirteenth embodiment of the present invention.

  Referring to FIG. 29, vehicle detector 21 includes an antenna (measurement antenna) 51 and a vehicle detector main body 57. The vehicle detector main body 57 includes a communication unit 52, a vehicle information creation unit 53, a management unit 55, and a storage unit 56.

  The antenna 51 is installed at a position higher than the road surface of the road 14, that is, above the road surface of the road 14, and receives radio waves transmitted from the transmission device 22. The antenna 51 converts the sensing radio wave received from the transmission device 22 into an electrical signal and sends it to the communication unit 52 and the vehicle information creation unit 53.

  The antenna 51 is also used for communication between the vehicle detector 21 and the transmission device 22. The antenna 51 receives an electrical signal from the communication unit 52, converts the received electrical signal into a radio wave, and transmits it to the transmission device 22.

  The communication unit 52 communicates with the transmission device 22 by transmitting and receiving signals to and from the transmission device 22 via the antenna 51. Specifically, the communication unit 52 transmits information received from the management unit 55 to the transmission device 22 via the antenna 51, and transmits information received from the transmission device 22 via the antenna 51 to the management unit 55.

  The vehicle information creation unit 53 measures the sensing radio wave received by the antenna 51 and creates vehicle information regarding the vehicle 10 based on a change in the measurement result. Specifically, the vehicle information creation unit 53 measures the level of the electric signal received from the antenna 51 at a predetermined interval, for example, information on the relationship between time and reception level as shown in FIG. 3 (hereinafter also referred to as time level information). To create).

  The vehicle information creation unit 53 calculates Tc / Ta from Ta and Tc included in the created time level information to obtain the vehicle length D of the vehicle 10 and determines the vehicle type of the vehicle 10 based on the vehicle length D.

  The vehicle information creation unit 53 creates vehicle length information indicating the vehicle length D of the vehicle 10 and vehicle type information indicating the vehicle type of the vehicle 10.

  In addition, the vehicle information creation unit 53 calculates D / Ta, calculates the speed of the vehicle 10 based on D / Ta, and creates speed information indicating the speed of the vehicle 10.

  The vehicle information creation unit 53 is not limited to a configuration that creates all of the time level information, the vehicle length information, the vehicle type information, and the speed information.

  The vehicle information creation unit 53 sends time level information, vehicle length information, vehicle type information, and speed information, which are created vehicle information, to the management unit 55.

  The management unit 55 stores the vehicle information received from the vehicle information creation unit 53 in the storage unit 56.

  The vehicle detection system 113 is not limited to a configuration in which one transmission device 22 is installed for one vehicle sensor 21, and a configuration in which a plurality of transmission devices 22 are installed for one vehicle sensor 21. It may be.

  In addition, the antenna 71 is not limited to a configuration installed below or on the road surface together with other units in the transmission device 22, and may be installed at a location separate from the other units. In this case, the other unit may be installed above the road surface, for example.

  Further, the vehicle information creation unit 53 may measure the sensing radio wave received by the antenna 51 and create the vehicle information by the same process as in the second embodiment.

  Further, the vehicle information creation unit 53 may measure the sensing radio wave received by the antenna 51 and create the vehicle information by the same processing as in the third embodiment. For example, the vehicle information creation unit 53 may create the vehicle information based on the change in the measurement result of the sensing radio wave and whether or not the communication unit 52 can receive the signal transmitted from the transmission device 22.

  In addition, the vehicle information creation unit 53 may measure the sensing radio wave received by the antenna 51 and create the vehicle information by the same process as in the fourth embodiment.

  The transmitting device 22 may alternately switch the frequency of the radiating sensing radio wave, sweep the frequency of the radiating sensing radio wave, or radiate the sensing radio wave having two different frequency components. May be. In these cases, the vehicle information creation unit 53 in the vehicle detector 21 measures the sensing radio wave received by the antenna 51, and creates vehicle information by the same processing as in the fifth embodiment.

  In addition, the vehicle detector 21 may include two antennas 51. When the vehicle detector 21 includes two antennas 51, the vehicle information creation unit 53 measures the sensing radio wave received by each antenna 51, and creates vehicle information by the same processing as in the seventh embodiment. May be.

  The transmission device 22 may transmit the measurement result of the magnetic field level by the magnetic sensor 78 to the vehicle detector 21. When the transmission device 22 transmits the measurement result of the magnetic field level by the magnetic sensor 78 to the vehicle sensor 21, the vehicle information creation unit 53 in the vehicle sensor 21 includes the measurement result of the magnetic field level received from the transmission device 22, The vehicle information may be created by a process similar to that of the eighth embodiment by comparing the measurement result of the sensing radio wave received by the antenna 51.

  Hereinafter, the measurement result of the sensing radio wave by the vehicle detector 21 when the vehicle 10 passes above the transmission device 22 will be described.

  FIG. 26 also shows an example of a measurement system for the reception level of sensing radio waves using the vehicle detector and the transmission device according to the thirteenth embodiment of the present invention.

  The transmission device 22 is embedded under the road surface of the road 14 and radiates sensing radio waves.

  The antenna 51 is installed at a location 10 m away from the transmission device 22 and receives the sensing radio wave radiated from the transmission device 22. The vehicle detector 21 measures the reception level of the sensing radio wave received by the antenna 51.

  The vehicle 10 is a light vehicle and travels on the road 14 at a speed of 30 to 40 km per hour and passes above the transmission device 22.

  FIG. 30 is a diagram illustrating an example of measurement results of sensing radio waves by the vehicle detector according to the thirteenth embodiment of the present invention.

  With reference to FIG. 30, the horizontal axis of the graph represents time [seconds] from the start of measurement, and the vertical axis represents the reception level [dBm] of the sensing radio wave received by the antenna 51.

  The reception level, which was minus 83 dBm at the beginning, starts to decrease after about 1.8 seconds from the start of measurement, reaches minus 97 dBm after about 2.0 seconds from the start of measurement, and then rises to about 3.2 from the start of measurement. After a second, it stabilized at minus 83 dBm.

  From the measurement result shown in FIG. 30, when the vehicle 10 passes above the transmission device 22, the vehicle detector 21 confirms the change in the reception level of the sensing radio wave and based on the change in the reception level of the sensing radio wave. It can be seen that the passage of the vehicle 10 can be sensed.

  FIG. 31 is a diagram showing another example of the measurement result of the sensing radio wave by the vehicle detector according to the thirteenth embodiment of the present invention.

  FIG. 31 shows the measurement results of the sensing radio waves when two vehicles 10 pass over the transmitter 22 in succession. With reference to FIG. 31, the horizontal axis of the graph represents time [seconds] from the start of measurement, and the vertical axis represents the reception level [dBm] of the sensing radio wave received by the antenna 51.

  The reception level, which was minus 77 dBm at the beginning, started to rise after about 0.9 seconds from the start of measurement, and reached minus 75 dBm after about 1.1 seconds from the start of measurement. The reception level then dropped, reached minus 82 dBm after about 1.6 seconds from the start of measurement, and rose again, and stabilized at minus 77 dBm after about 2.0 seconds from the start of measurement.

  Further, the reception level started to increase after about 3.7 seconds from the start of measurement, and reached minus 74 dBm after about 3.9 seconds from the start of measurement. The reception level then decreased, reached minus 84 dBm after about 4.3 seconds from the start of measurement, rose again, and stabilized at minus 77 dBm after about 4.7 seconds from the start of measurement.

  From the measurement results shown in FIG. 31, when a plurality of vehicles 10 pass above the transmission device 22, the vehicle detector 21 can detect the number of vehicles 10 passing based on the change in the reception level of the sensing radio wave. I understand.

  Note that the reception level of the sensing radio wave received by the antenna 51 temporarily increased from about 0.9 seconds after the start of measurement. The sensing radio wave reflected from the front surface of the first vehicle 10 is applied to the antenna 51. It is thought that it is because it reached.

  In addition, the reception level of the sensing radio wave received by the antenna 51 temporarily increased from about 3.7 seconds after the start of measurement. The sensing radio wave reflected from the front surface of the second vehicle 10 is applied to the antenna 51. It is thought that it is because it reached.

  As described above, in the vehicle detector according to the thirteenth embodiment of the present invention, the antenna 51 receives the sensing radio wave transmitted from the transmission device 22. The transmission device 22 includes an antenna 71 which is embedded under a road surface through which the vehicle 10 passes or under a road surface through which the vehicle 10 stops, or is installed on a road surface through which the vehicle 10 passes or a road surface through which the vehicle 10 stops. . The vehicle information creation unit 53 measures the sensing radio wave received by the antenna 51 and creates vehicle information regarding the vehicle 10 based on a change in the measurement result. The antenna 51 is installed above the road surface on which the vehicle 10 passes or above the road surface on which the vehicle 10 stops.

  With such a configuration, from the change in the value obtained by the measurement of the sensing radio wave, for example, not only the information on whether or not the vehicle 10 exists above the transmission device 22, but also the speed, the vehicle type, or the vehicle 10 Information such as the direction of travel can also be acquired. Therefore, it is possible to easily grasp the detailed traffic situation without being greatly affected by the surrounding environment.

  In the vehicle detector according to the thirteenth embodiment of the present invention, the communication unit 52 communicates with the transmission device 22 by transmitting and receiving signals to and from the transmission device 22 via the antenna 51. The vehicle information creation unit 53 creates vehicle information based on the change in the measurement result and whether or not the communication unit 52 can receive the signal transmitted from the transmission device 22.

  With such a configuration, for example, vehicle information can be created from the measurement result of the sensing radio wave used for the communication in the case where the communication with the transmission device 22 can be satisfactorily performed. It is possible to create more reliable vehicle information by using a sensing radio wave with less quality and good quality.

  In the vehicle sensing system according to the thirteenth embodiment of the present invention, the antenna 71 is embedded under the road surface through which the vehicle 10 passes, or under the road surface where the vehicle 10 stops, or the vehicle 10 passes through. It is installed on the road surface where the vehicle 10 stops or the road where the vehicle 10 stops. The antenna 51 receives the sensing radio wave transmitted from the antenna 71. The vehicle information creation unit 53 measures the sensing radio wave received by the antenna 51 and creates vehicle information regarding the vehicle 10 based on a change in the measurement result. The antenna 51 is installed above the road surface on which the vehicle 10 passes or above the road surface on which the vehicle 10 stops.

  With such a configuration, from the change in the value obtained by the measurement of the sensing radio wave, for example, not only the information on whether or not the vehicle 10 exists above the transmission device 22, but also the speed, the vehicle type, or the vehicle 10 Information such as the direction of travel can also be acquired. Therefore, it is possible to easily grasp the detailed traffic situation without being greatly affected by the surrounding environment.

  Moreover, in the vehicle sensing system which concerns on the 13th Embodiment of this invention, the transmitter 22 operate | moves using the electric power stored in the battery. The sensing radio wave transmission unit 73 transmits a sensing radio wave using the antenna 71. The sleep control unit 74 operates the sensed radio wave transmission unit 73 intermittently. The sleep control unit 74 restarts the operation of the sensing radio wave transmission unit 73 when the predetermined condition is satisfied after the operation of the sensing radio wave transmission unit 73 is stopped.

  With such a configuration, when the vehicle 10 does not pass above the transmission device 22 for a predetermined period of time, the operation of the sensing radio wave transmission unit 73 is stopped, and when the vehicle 10 is about to pass above the transmission device 22, Since an intermittent operation such as resuming the operation of the transmission unit 73 can be performed, power consumption of the battery by the vehicle detector 21 can be suppressed, and for example, the frequency of battery replacement can be reduced. In particular, when the transmitter 22 with a built-in battery or a single battery is embedded under the road surface, the maintenance cost of the transmitter 22 such as battery replacement work can be effectively reduced.

  In the vehicle sensing system according to the thirteenth embodiment of the present invention, the communication unit 52 communicates with the transmission device 22 by transmitting and receiving signals to and from the transmission device 22 via the antenna 51. The vehicle information creation unit 53 creates vehicle information based on the change in the measurement result and whether or not the communication unit 52 can receive the signal transmitted from the transmission device 22.

  With such a configuration, for example, vehicle information can be created from the measurement result of the sensing radio wave used for the communication in the case where the communication with the other device can be satisfactorily performed. It is possible to create more reliable vehicle information by using a sensing radio wave with less quality and good quality.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Fourteenth embodiment>
The present embodiment relates to a vehicle sensing system that determines whether or not a vehicle is present above a transmission device, as compared with the vehicle sensing system according to the thirteenth embodiment. The contents other than those described below are the same as those of the vehicle sensing system according to the thirteenth embodiment.

  In the vehicle sensing system 114 according to the fourteenth embodiment of the present invention, the antenna 71 of the transmission device 22 is embedded under the road surface on which the vehicle 10 stops. For example, the antennas 71 of the transmission device 22 are embedded one by one in a frame where the vehicle 10 is parked in the parking lot together with other units of the transmission device 22. Moreover, the vehicle detector 21 is installed beside the parking lot, for example.

  FIG. 32 is a diagram showing an example of a sequence in which the vehicle sensor according to the fourteenth embodiment of the present invention creates vehicle information.

  Each device in the vehicle sensing system includes a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including a part or all of each step of the sequence shown below from a memory (not shown). Each of the programs of the plurality of apparatuses can be installed from the outside. The programs of the plurality of apparatuses are distributed while being stored in a recording medium.

  FIG. 32 shows a case where two transmission devices 22 </ b> A and 22 </ b> B are installed for one vehicle sensor 21.

  Referring to FIG. 32, vehicle detector 21 transmits a transmission instruction, which is an instruction to radiate sensing radio waves, to transmission device 22A regularly or irregularly (step S51).

  Next, the transmitting device 22A receives a transmission instruction from the vehicle detector 21, and radiates, for example, a radio wave obtained by modulating a signal including specific data as a sensing radio wave for a predetermined period (step S52).

  Next, the vehicle detector 21 receives the sensing radio wave radiated from the transmission device 22A, and determines whether or not the vehicle 10 is parked in the frame where the transmission device 22A is installed (step S53). .

  Specifically, the vehicle information creation unit 53 in the vehicle detector 21 determines whether the transmission device 22A has received the signal transmitted from the transmission device 22A and the reception level of the sensing radio wave received by the antenna 51. It is determined whether or not the vehicle 10 is parked in the installed frame.

  For example, in the vehicle detector 21, when the communication unit 52 can restore the original data from the sensing radio wave received by the antenna 51, the vehicle information creation unit 53 sends a signal from the transmission device 22A. Is determined to have been received.

  Further, when the communication unit 52 cannot restore the original data from the sensing radio wave received by the antenna 51, the vehicle information creation unit 53 indicates that the communication unit 52 could not receive the signal from the transmission device 22 </ b> A. judge.

  The vehicle information creation unit 53 is a case where the communication unit 52 can receive a signal from the transmission device 22A and the reception level of the sensing radio wave received by the antenna 51 is greater than or equal to a predetermined value. Is determined that the vehicle 10 is not parked in the frame in which the transmission device 22A is installed.

  Further, the vehicle information creation unit 53, when the communication unit 52 cannot receive the signal from the transmission device 22A, or when the reception level of the sensing radio wave received by the antenna 51 is below a predetermined value. Then, it is determined that the vehicle 10 is parked in the frame in which the transmission device 22A is installed.

  Note that the vehicle information creation unit 53 also causes the communication unit 52 to transmit the transmission device 22A even when the antenna 51 cannot receive the sensing radio wave from the transmission device 22 for a predetermined period after the vehicle detector 21 transmits the transmission instruction. It is determined that the signal from is not received.

  Next, the vehicle detector 21 transmits a transmission instruction to the transmission device 22B (step S54).

  Next, the transmission device 22B receives a transmission instruction from the vehicle detector 21, and radiates, for example, a radio wave obtained by modulating a signal including specific data as a detection radio wave for a certain period (step S55).

  Next, the vehicle detector 21 receives the sensing radio wave radiated from the transmission device 22B, and determines whether or not the vehicle 10 is parked in the frame where the transmission device 22B is installed (step S56). .

  Specifically, the vehicle information creation unit 53 in the vehicle detector 21 determines whether the transmission device 22B receives the signal transmitted from the transmission device 22B and the reception level of the sensing radio wave received by the antenna 51. It is determined whether or not the vehicle 10 is parked in the installed frame (step S57).

  Next, the vehicle information creation unit 53 installs the transmission device 22A and the transmission device 22B based on the parking determination result in the frame in which the transmission device 22A is installed and the parking determination result in the frame in which the transmission device 22B is installed. Parking information indicating the parking status of the vehicle 10 in the parking lot that has been created is created as vehicle information (step S57).

  Then, the vehicle information creation unit 53 sends the created vehicle information to the management unit 55. The management unit 55 stores the vehicle information received from the vehicle information creation unit 53 in the storage unit 56 (step S58).

  According to the procedure as described above, each transmission device 22 can transmit vehicle information at a timing different from that of the other transmission devices 22, so that a detection radio wave transmitted by itself and a radio wave transmitted from the other transmission device 22 are transmitted. Collisions can be avoided.

  Further, since the transmission device 22 only needs to transmit the sensing radio wave during a specific period, the transmission time of the sensing radio wave can be reduced, and for example, the battery power consumption in the battery unit 77 can be suppressed.

  Further, the sleep control unit 74 in each transmission device 22 may cause the sensed radio wave transmission unit 73 to operate intermittently. Specifically, when the transmission instruction from the vehicle detector 21 is not received by the antenna 71 for a predetermined period, the sleep control unit 74 stops the operation of the detected radio wave transmission unit 73, and the antenna 71 receives the signal from the vehicle detector 21. When the transmission instruction is received, the operation of the sensed radio wave transmission unit 73 may be resumed.

  When the vehicle detector 21 periodically transmits a transmission instruction, the sleep control unit 74 in the transmission device 22 operates the detected radio wave transmission unit 73 during a time period when the vehicle detector 21 does not transmit the transmission instruction. The operation of the sensing radio wave transmission unit 73 may be resumed during a time period when the vehicle detector 21 transmits a transmission instruction.

  Further, the antenna of the transmission device 22 is not limited to the configuration embedded under the road surface of the parking lot, but is embedded under the road surface of the road 14 where the vehicle 10 stops, for example, under the stop position of the vehicle 10 at the railroad crossing. It may be a configuration.

  Further, the antenna of the transmission device 22 is not limited to the configuration embedded in the parking lot or the road surface of the road 14, but may be installed on the road surface, for example.

  Since other configurations and operations are the same as those of the vehicle sensing system according to the thirteenth embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Fifteenth embodiment>
The present embodiment relates to a vehicle sensing system that creates vehicle information using a magnetic field as compared to the vehicle sensing system according to the first embodiment. The contents other than those described below are the same as in the vehicle sensing system according to the first embodiment.

[Configuration and basic operation]
FIG. 33 is a diagram showing a configuration of a vehicle sensing system according to the fifteenth embodiment of the present invention.

  Referring to FIG. 33, the vehicle sensing system 115 includes a vehicle sensor 211 and a receiving device 212.

  The vehicle 10 is traveling on the road 14 in the direction indicated by the arrow 70. The vehicle detector 211 is embedded under the road surface of the road 14, for example. The vehicle sensor 211 includes a magnetic sensor, and creates vehicle information related to the vehicle 10 passing above itself based on a change in the magnetic field. The magnetic sensor included in the vehicle sensor 211 is a geomagnetic sensor, for example. The vehicle sensor 211 includes, for example, a battery, and operates using electric power stored in the battery.

  The receiving device 212 acquires vehicle information from the vehicle sensor 211 by communicating with the vehicle sensor 211. The receiving device 212 is installed beside the road 14 on which the vehicle 10 travels, for example.

  FIG. 34 is a diagram showing measurement of a magnetic field in the vehicle sensing system according to the fifteenth embodiment of the present invention.

  Referring to FIG. 34, vehicle 10 includes a strong magnetic field part (specific part) 16 that generates a strong magnetic field, for example. The strong magnetic field unit 16 is, for example, a dynamo that the vehicle 10 generally includes.

  34 indicates a corresponding position of the front end of the vehicle 10 on the road surface, for example, a point directly below the front end of the vehicle 10 on the road surface, and a corresponding position of the magnetic sensor of the vehicle detector 211 on the road surface, for example, the vehicle detector 211 on the road surface. The distance from the point directly above the magnetic sensor is shown.

  L1 indicates the distance between the front end of the vehicle 10 and the strong magnetic field part 16, for example. L5 indicates the distance between the front end and the rear end of the vehicle 10, for example.

  When the strong magnetic field unit 16 is located immediately above the vehicle sensor 211, that is, for example, when L = L1, the level of the magnetic field in the vehicle sensor 211 is the highest.

  FIG. 35 is a diagram showing an example of the relationship between the distance L shown in FIG. 34 and the magnetic field level in the vehicle detector in the vehicle sensing system according to the fifteenth embodiment of the present invention.

  FIG. 35 shows the measurement result of the magnetic field by the magnetic sensor included in the vehicle sensor 211. Referring to FIG. 35, the horizontal axis of the graph indicates the distance L, and the vertical axis indicates the level of the magnetic field in the vehicle sensor 211. The graph shows the level of the magnetic field in the vehicle sensor 211 when the vehicle 10 passes above the vehicle sensor 211.

  When the vehicle 10 is sufficiently away from the vehicle detector 211, that is, in a steady state, the level of the magnetic field in the vehicle detector 211 converges to a range from level Hh1 to level Hh2, specifically, level Hm. The level Hm indicates, for example, the level of geomagnetism.

  The magnetic field level starts to rise, for example, at time t0 when L = 0 due to the approach of the vehicle 10. For example, the time t0 is a time at which the magnetic field level in the vehicle detector 211 that has converged in the range from the level Hh1 to the level Hh2 starts to rise out of the range due to the approach of the vehicle 10.

  Then, the magnetic field level reaches a peak level Ht at time t1 when L = L1 and becomes constant, and starts to decrease at time t2 when L = L2. The magnetic field level reaches the level Hb at time t3 when L = L3 and becomes constant, and starts to rise from time t4 when L = L4.

  Then, the magnetic field level again converges to the range from level Hh1 to level Hh2, specifically, level Hm at time t5 when L = L5. Time t5 is, for example, the time at which the level of the magnetic field in the vehicle detector 211 has converged again within the range after the vehicle 10 passes the range from the level Hh1 to the level Hh2.

  Here, the strong magnetic field portion 16, which is a dynamo, for example, is provided at the front portion of the vehicle 10 in most vehicles 10. For this reason, the length of the distance L5 with respect to the distance L1 is smaller when the vehicle 10 is a large vehicle than when the vehicle 10 is a small vehicle.

  From this, for example, the length of the time Tf from the time t0 to the time t5 with respect to the time Tr from the time t0 to the time t1 is longer than that in the case where the vehicle 10 is a large vehicle and the vehicle 10 is a small vehicle. Get smaller.

  The vehicle sensor 211 estimates the vehicle type of the vehicle 10 that has passed above itself based on the ratio of the time Tr and the time Tf. Here, the vehicle detector 211 classifies the vehicle 10 according to a rough classification of the vehicle type, such as whether or not the vehicle 10 that has passed over it is a large vehicle.

  For example, the vehicle sensor 211 stores in advance an average distance L1 of large vehicles and an average distance L1 of vehicles other than large vehicles. The vehicle sensor 211 selects a distance L1 corresponding to the estimated vehicle type from the stored distances L1, and calculates the speed of the vehicle 10 using the selected distance L1.

  Then, the vehicle detector 211 calculates the vehicle length of the vehicle 10 based on the calculated speed of the vehicle 10 and determines the vehicle type of the vehicle 10 based on the calculated vehicle length. Here, the vehicle detector 211 discriminates the vehicle type of the vehicle 10 according to a more detailed category than the vehicle type category applied when the vehicle type is estimated as described above. Specifically, for example, the vehicle detector 211 classifies the vehicle 10 into one of a large vehicle, a medium vehicle, and a small vehicle.

  FIG. 36 is a diagram showing the configuration of the vehicle detector according to the fifteenth embodiment of the present invention.

  Referring to FIG. 36, the vehicle detector 211 includes an antenna 82, a communication unit 83, a management unit 84, a storage unit 85, a magnetic sensor 86, a sleep control unit 87, a monitoring unit 88, and a battery unit. 89 and a vehicle information creation unit 90.

  The vehicle information creation unit 90 includes an acquisition unit 92, a speed calculation unit 93, a vehicle length calculation unit 94, and a determination unit 95.

  Battery unit 89 includes a battery, converts the level of the output voltage of the battery into a predetermined voltage level, and supplies the converted voltage to each unit in vehicle detector 211.

  The antenna 82 is used for communication between the vehicle sensor 211 and the receiving device 212. The communication unit 83 communicates with the receiving device 212 via the antenna 82. Specifically, the communication unit 83 transmits information received from the management unit 84 to the reception device 212 via the antenna 82, and transmits information received from the reception device 212 via the antenna 82 to the management unit 84.

  The storage unit 85 stores information indicating the position of the strong magnetic field unit 16 in the vehicle 10. Specifically, for example, the storage unit 85 stores the distance L1 as the position of the strong magnetic field unit 16.

  More specifically, the vehicle 10 can be classified into any one of vehicle types such as a large vehicle, a medium vehicle, and a small vehicle. The memory | storage part 85 has memorize | stored the distance L1 for every vehicle model of the vehicle 10, for example.

  Here, the storage unit 85 stores in advance an average distance L1 of large vehicles and an average distance L1 of vehicles other than large vehicles.

  The magnetic sensor 86 measures the magnetic field and sends a sensor signal indicating the measurement result to the monitoring unit 88. The monitoring unit 88 uses the sensor signal received from the magnetic sensor 86 to monitor the change in the magnetic field accompanying the traveling of the vehicle 10.

  For example, when the monitoring unit 88 recognizes that the vehicle 10 has passed over the vehicle detector 211 based on the sensor signal, the monitoring unit 88 generates magnetic field change information indicating a change in the magnetic field when the vehicle 10 passes. 90 to the acquisition unit 92. The magnetic field change information is, for example, information indicating a time change of the magnetic field level.

  The acquisition unit 92 acquires the timing at which the change of the magnetic field satisfies a predetermined condition based on the monitoring result of the monitoring unit 88. The predetermined condition is, for example, that the change in the magnetic field matches or resembles a predetermined pattern.

  Specifically, for example, based on the magnetic field change information received from the monitoring unit 88, the acquisition unit 92 first increases the magnitude of the magnetic field in a state of being converged on the predetermined range outside the predetermined range. A timing, a second timing at which the magnitude of the magnetic field reaches a peak value after the first timing, and a third timing at which the magnitude of the magnetic field decreases and converges to a predetermined range after the second timing are acquired.

  For example, the acquisition unit 92 determines that the magnitude of the magnetic field has converged to the predetermined range when the state in which the magnitude of the magnetic field is included in the predetermined range continues for a predetermined time after the second timing. Then, the acquisition unit 92 acquires the timing before the predetermined time of the timing when the magnitude of the magnetic field converges within the predetermined range as the third timing. Here, the “magnitude of the magnetic field” is, for example, the magnitude of the magnetic field based on the magnitude of the magnetic field in a steady state. The “predetermined range” is a range including the level of the magnetic field in the steady state.

  For example, the acquisition unit 92 acquires time t0 illustrated in FIG. 35 as the first timing, acquires time t1 as the second timing, and acquires time t5 as the third timing.

  The speed calculation unit 93 estimates the position of the strong magnetic field unit 16 in the vehicle 10 based on the timing acquired by the acquisition unit 92. Specifically, for example, the speed calculation unit 93 estimates the position of the strong magnetic field unit 16 based on the second timing and the third timing acquired by the acquisition unit 92.

  For example, as described with reference to FIG. 35, the speed calculation unit 93 determines that the own vehicle is based on the ratio between the time Tr that is the difference between the time t1 and the time t0 and the time Tf that is the difference between the time t5 and the time t0. The vehicle type of the vehicle 10 that has passed above the sensor 211 is estimated. Here, for example, the speed calculation unit 93 classifies the vehicles 10 according to the rough classification of the vehicle type, such as whether or not the vehicle 10 that has passed over the vehicle detector 211 is a large vehicle.

  And the speed calculating part 93 estimates the position of the strong magnetic field part 16, for example, distance L1, based on the estimated vehicle type. Specifically, the speed calculation unit 93 selects the distance L1 corresponding to the estimated vehicle type from the plurality of distances L1 stored in the storage unit 85, and acquires the selected distance L1 via the management unit 84.

  The speed calculation unit 93 calculates the speed of the vehicle 10 based on the timing acquired by the acquisition unit 92 and the estimated position of the strong magnetic field unit 16.

  Specifically, for example, the speed calculation unit 93 calculates the speed of the vehicle 10 based on the first timing and the second timing acquired by the acquisition unit 92 and the estimated position of the strong magnetic field unit 16, for example, the distance L1. To do.

Specifically, for example, when the speed of the vehicle 10 is the speed Vs, the speed calculation unit 93 calculates the speed Vs according to the following equation.
Vs = L1 / (t1-t0)

  For example, the vehicle length calculation unit 94 calculates the vehicle length of the vehicle 10 based on the speed Vs calculated by the speed calculation unit and the third timing acquired by the acquisition unit 92.

Specifically, for example, when the vehicle length of the vehicle 10 is Dm, the vehicle length calculation unit 94 calculates the vehicle length Dm according to the following equation.
Dm = Vs × (t5−t0)

  The determination unit 95 determines the vehicle type of the vehicle 10 based on the vehicle length Dm calculated by the vehicle length calculation unit 94, for example.

  Specifically, for example, the determination unit 95 classifies the vehicle 10 into one of a large vehicle, a medium vehicle, and a small vehicle according to the vehicle length Dm.

  The management unit 84 acquires, as vehicle information, each of the speed Vs calculated by the speed calculation unit 93, the vehicle length Dm calculated by the vehicle length calculation unit 94, and the vehicle type of the vehicle 10 determined by the determination unit 95. And stored in the storage unit 85.

  As described above, the configuration using the magnetic field can suppress the influence of the surrounding environment such as the brightness of the surroundings or the presence of rain as compared with the camera-type vehicle sensing device described above, as in the configuration using the radio wave. it can.

  When receiving the vehicle information from the vehicle sensor 211, the reception device 212 transmits a reception enable notification to the vehicle sensor 211 as a notification that the vehicle information can be received.

  The communication unit 83 in the vehicle sensor 211 receives the notification that the vehicle is received from the receiving device 212, that is, the communication unit 83 receives the notification that the vehicle is received via the antenna 82. Information is transmitted to the receiving device 212.

  Specifically, when the communication unit 83 receives a receivable notification via the antenna 82, the management unit 84 acquires vehicle information from the storage unit 85 and sends the vehicle information to the communication unit 83. The communication unit 83 transmits the vehicle information received from the management unit 84 to the receiving device 212 via the antenna 82.

  When reception of the vehicle information is completed, the reception device 212 transmits a reception completion notification to the vehicle detector 211 as a notification that reception of the vehicle information has been completed.

  The communication unit 83 transmits vehicle information to the receiving device 212 for the first time, then repeatedly transmits the vehicle information, and when the vehicle detector receives a notification from the receiving device 212 that the reception of the vehicle information is completed. , Stop sending vehicle information.

  When the monitoring unit 88 senses the approach of the vehicle 10 based on the sensor signal received from the magnetic sensor 86, the monitoring unit 88 sends a vehicle approach notification for notifying the approach of the vehicle 10 to the sleep control unit 87.

  The sleep control unit 87 intermittently operates all or part of the acquisition unit 92, the speed calculation unit 93, the vehicle length calculation unit 94, and the determination unit 95 included in the vehicle information creation unit 90.

  For example, when the sleep control unit 87 does not continuously receive the vehicle approach notification from the monitoring unit 88 for a predetermined time, all or part of the acquisition unit 92, the speed calculation unit 93, the vehicle length calculation unit 94, and the determination unit 95 Stop the operation.

  In addition, the sleep control unit 87 is a unit that has stopped the operation when the predetermined condition is satisfied after the operation of each unit included in the vehicle information creation unit 90 is stopped. The acquisition unit 92, the speed calculation unit 93, the vehicle length The operation of all or part of the calculation unit 94 and the determination unit 95 is resumed. Specifically, when receiving a vehicle approach notification from the monitoring unit 88, the sleep control unit 87 resumes the operation of the unit that has stopped operating.

  The vehicle detector 211 may include a vibration sensor that detects the approach of the vehicle 10 by vibration. In this case, the monitoring unit 88 detects the approach of the vehicle 10 based on the sensor signal received from the vibration sensor, and sends a vehicle approach notification to the sleep control unit 87.

  In addition, the sleep control unit 87 may repeatedly stop the operation of each unit included in the vehicle information creation unit 90 and restart the operation at predetermined intervals according to, for example, statistical accuracy required for the vehicle sensing system. .

[Operation]
Each device in the vehicle sensing system 115 includes a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including a part or all of each step of the following sequence from a memory (not shown). Each of the programs of the plurality of apparatuses can be installed from the outside. The programs of the plurality of apparatuses are distributed while being stored in a recording medium.

  FIG. 37 is a diagram illustrating an example of a sequence in which the vehicle detector in the vehicle detection system transmits vehicle information to the reception device.

  FIG. 37 shows a case where two vehicle detectors 211A and 211B are installed for one receiving device 212.

  Referring to FIG. 37, vehicle detector 211A senses a passing vehicle 10 based on a change in magnetic field, creates vehicle information of the vehicle 10 (step S62), and stores the created vehicle information in a storage unit. It saves in 85 (step S63). Each time the vehicle 10 passes, the vehicle detector 211A creates vehicle information of the vehicle 10 and stores it in the storage unit 85 (step S62 and step S63).

  Further, the vehicle detector 211B senses the vehicle 10, creates vehicle information of the vehicle 10 (step S64), and stores the created vehicle information in the storage unit 85 (step S65). Each time the vehicle 10 passes, the vehicle detector 211B creates vehicle information of the vehicle 10 and stores it in the storage unit 85 (steps S64 and S65).

  Next, the reception device 212 transmits a reception enable notification to the vehicle sensor 211A (step S66).

  Next, the vehicle detector 211A receives the reception enable notification from the reception device 212, and transmits the vehicle information to the reception device 212 when the vehicle information is stored in its storage unit 85 (step S67). . The vehicle detector 211A repeatedly transmits the vehicle information to the receiving device 212, for example.

  Next, when the vehicle information transmitted from the vehicle sensor 211A is properly received, the reception device 212 transmits a reception completion notification to the vehicle sensor 211A (step S68).

  Next, the vehicle detector 211A receives a reception completion notification from the reception device 212 and stops transmitting vehicle information. Then, the vehicle detector 211A deletes the vehicle information transmitted to the receiving device 212 from its own storage unit 85 (step S69).

  Next, the receiving device 212 transmits a receivable notification to the vehicle detector 211B (step S70).

  Next, the vehicle detector 211B receives the notification that reception is possible from the reception device 212, and when the vehicle information is stored in its own storage unit 85, transmits the vehicle information to the reception device 212 (step S71). . The vehicle detector 211B repeatedly transmits the vehicle information to the receiving device 212, for example.

  Next, when the vehicle information transmitted from the vehicle sensor 211B is properly received, the reception device 212 transmits a reception completion notification to the vehicle sensor 211B (step S72).

  Next, the vehicle detector 211B receives a reception completion notification from the receiving device 212 and stops transmitting vehicle information. Then, the vehicle sensor 211B deletes the vehicle information transmitted to the receiving device 212 from its own storage unit 85 (step S73).

  Next, the receiving device 212 creates comprehensive vehicle information based on the vehicle information received from the vehicle sensor 211A and the vehicle information received from the vehicle sensor 211B (step S74).

  For example, when one vehicle 10 travels on the road 14 and a plurality of vehicle detectors 211 generate vehicle information for the vehicle 10 and transmit it to the receiving device 212, the receiving device 212 The vehicle information received from each vehicle detector 211 within a predetermined interval is associated with each other as vehicle information related to the specific vehicle 10. And the receiver 212 produces more exact vehicle information from the vehicle information linked | related with each other.

  Specifically, for example, the receiving device 212 acquires the speed of the vehicle 10 calculated by each vehicle sensor 211 from a plurality of vehicle information associated with each other, and averages the acquired speeds of the vehicle 10. A more accurate speed of the vehicle 10 is calculated.

  Further, for example, the receiving device 212 acquires the vehicle length of the vehicle 10 calculated by each vehicle sensor 211 from a plurality of vehicle information associated with each other, and averages the vehicle lengths of the acquired vehicles 10. A more accurate vehicle length of the vehicle 10 is calculated. Then, the reception device 212 determines the vehicle type of the vehicle 10 from the calculated vehicle length of the vehicle 10.

  Further, for example, the receiving device 212 accumulates information indicating the speed of the vehicle 10 calculated by itself and the vehicle type of the vehicle 10 determined by itself for a predetermined period, and calculates the average speed and the number of vehicle types of the vehicle 10 during the period. To do.

  Note that the vehicle sensing system 115 according to the fifteenth embodiment of the present invention is not limited to a configuration in which one or two vehicle detectors 211 are installed for one receiving device 212, but one receiving device 212. The configuration may be such that three or more vehicle detectors 211 are installed.

  In the vehicle sensing system 115 according to the fifteenth embodiment of the present invention, the acquisition unit 92 sets the timing at which the magnitude of the magnetic field in a state where it converges to the predetermined range starts to rise outside the predetermined range. Although the configuration is such that it is acquired as one timing, it is not limited to this. For example, the acquisition unit 92 may be configured to acquire, as the first timing, the timing at which the magnitude of the magnetic field that has converged to a predetermined value starts to increase.

  In the vehicle sensing system 115 according to the fifteenth embodiment of the present invention, the acquisition unit 92 acquires, as the third timing, the timing at which the magnitude of the magnetic field decreases and converges to a predetermined range after the second timing. Although it is the configuration, it is not limited to this. For example, the acquisition unit 92 may be configured to acquire the timing at which the magnitude of the magnetic field decreases and converges to a predetermined value after the second timing as the third timing.

  Further, although the vehicle detection system 115 according to the fifteenth embodiment of the present invention is configured to create vehicle information in the vehicle detector 211, the present invention is not limited to this. The vehicle sensor may be configured to create vehicle information.

  In this case, for example, the vehicle sensor 211 measures a change in the magnetic field using the magnetic sensor 86 and transmits information indicating the measurement result to the receiving device 212.

  The receiving device 212 includes, for example, a monitoring unit 88 and a vehicle information creation unit 90. The receiving device 212 monitors the change of the magnetic field based on the information received from the vehicle detector 211, and creates the vehicle information based on the monitoring result.

  Further, the vehicle detection system 115 according to the fifteenth embodiment of the present invention is configured such that the vehicle detector 211 is embedded under the road surface of the road 14, but the present invention is not limited to this. The vehicle detector 211 may be configured on the road surface of the road 14, or the vehicle sensor 211 may be configured on the side of the road 14.

  In the vehicle detection system 115 according to the fifteenth embodiment of the present invention, the vehicle detector 211 is configured to include the battery unit 89, but the present invention is not limited to this. The battery unit 89 may be omitted. In this case, the vehicle sensor 211 is supplied with power from, for example, a battery installed outside the vehicle sensor 211.

  In the vehicle detection system 115 according to the fifteenth embodiment of the present invention, the vehicle detector 211 is configured to calculate the speed Vs and the vehicle length Dm of the vehicle 10 and to determine the vehicle type of the vehicle 10. However, the present invention is not limited to this. For example, the vehicle detector 211 may be configured to calculate the speed Vs and the vehicle length Dm of the vehicle 10 and not to determine the vehicle type of the vehicle 10, or to calculate the speed Vs of the vehicle 10 The configuration may be such that the calculation of the length Dm and the determination of the vehicle type of the vehicle 10 are not performed.

  In the vehicle detector 211 according to the fifteenth embodiment of the present invention, the storage unit 85 uses a plurality of distances L1 corresponding to the vehicle type of the vehicle 10 as information indicating the position of the strong magnetic field unit 16 in the vehicle 10. Although the configuration is stored in advance, the configuration is not limited to this, and a configuration in which one representative distance L1 is stored may be used.

  In this case, the speed calculation unit 93 calculates the speed of the vehicle 10 based on the timing acquired by the acquisition unit 92 and the position of the strong magnetic field unit 16 stored by the storage unit 85, that is, the representative distance L1. .

  Specifically, for example, the speed calculation unit 93 does not estimate the vehicle type of the vehicle 10 that has passed over its own vehicle sensor 211 in a stage before calculating the speed Vs. And when calculating the speed Vs of the vehicle 10, said typical distance L1 which the memory | storage part 85 memorize | stores is used.

  Further, in the vehicle detector 211 according to the fifteenth embodiment of the present invention, the communication unit 83 includes all the information indicating the speed Vs, the information indicating the vehicle length Dm, and the information indicating the vehicle type of the vehicle 10 as vehicle information. Although the configuration is such that the transmission is performed, the present invention is not limited to this, and a configuration in which part of the information is transmitted may be used.

  Further, in the vehicle detector 211 according to the fifteenth embodiment of the present invention, the communication unit 83 is configured to transmit vehicle information to the receiving device 212 when receiving a reception enable notification from the receiving device 212. However, the present invention is not limited to this, and the vehicle information may be transmitted to the receiving device 212 when a transmission instruction is received from the receiving device 212.

  The vehicle detector 211 and the vehicle detection system 115 according to the fifteenth embodiment of the present invention are at least one of the configurations of the vehicle detector and the vehicle detection system according to the first to fourteenth embodiments of the present invention. It is possible to combine with parts.

  For example, the vehicle detector 211 according to the fifteenth embodiment of the present invention may include a plurality of magnetic sensors 86. In this case, the magnetic sensors 86 are arranged away from each other along the road 14. The vehicle sensor 211 includes a plurality of monitoring units 88 and vehicle information creation units 90 corresponding to the magnetic sensors 86. The management unit 84 acquires vehicle information from each vehicle information creation unit 90 and stores it in the storage unit 85.

  Further, the vehicle detector 211 according to the fifteenth embodiment of the present invention is similar to the vehicle detector 11 according to the eighth embodiment of the present invention in that the reception level and magnetic field of the radio wave radiated from the radio device are the same. In other words, the traveling direction of the vehicle 10 may be determined based on which of the reception level and the magnetic field level changes first.

  In this case, the vehicle detector 211 further includes an antenna 31 and a vehicle information creation unit 33 shown in FIG.

  Further, the vehicle sensing system 115 according to the fifteenth embodiment of the present invention may include a synchronization processing unit 39, similarly to the vehicle sensing system according to the twelfth embodiment of the present invention.

  In this case, the synchronization processing unit 39 performs processing for synchronizing the receiving device 212 and each vehicle sensor 211 by transmitting and receiving time information between the receiving device 212 and the plurality of vehicle detectors 211. Each vehicle detector 211 transmits vehicle information to the receiving device 212 at a predetermined time for each vehicle detector 211.

  As described above, in the vehicle sensor according to the fifteenth embodiment of the present invention, the monitoring unit 88 monitors the change of the magnetic field. The acquisition unit 92 acquires the timing at which the change of the magnetic field satisfies a predetermined condition based on the monitoring result of the monitoring unit 88. The speed calculation unit 93 calculates the speed Vs of the vehicle 10 based on the timing acquired by the acquisition unit 92.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using the magnetic field. In addition, information on whether or not the vehicle has passed by the vehicle detector 211 as well as information on the speed of the vehicle can be acquired from changes in the magnetic field, so that detailed traffic conditions can be easily grasped. be able to. In addition, compared to a vehicle detector that measures the speed of a vehicle using radio waves, a set of a configuration for transmitting and receiving radio waves used for vehicle sensing is unnecessary, and a change in magnetic field can be detected with a single configuration. The speed of the vehicle can be obtained with a simpler configuration.

  Here, as a vehicle sensing system for acquiring the speed of the vehicle 10, the following configuration is also conceivable. In other words, the vehicle detection system includes two vehicle detectors installed at some distance along the road 14 and a receiving device that communicates with each of these vehicle detectors. The receiving device calculates the speed of the vehicle 10 based on the difference in time when the vehicle is detected by each vehicle detector and the distance between the vehicle detectors.

  Specifically, each vehicle sensor includes a magnetic field sensor, and acquires a time when the vehicle 10 passes above itself based on an output signal of the magnetic field sensor. Each vehicle detector transmits information indicating the acquired time to a receiving device installed beside the road 14. The receiving device calculates the time required for the vehicle 10 to pass between the two vehicle detectors based on the information received from each vehicle detector. Then, the receiving device calculates the speed of the vehicle 10 based on the calculated time and the distance between the vehicle detectors.

  However, in this vehicle sensing system, the receiving device collects information from the two vehicle detectors and calculates the speed of the vehicle 10 by performing calculations based on the collected information. A receiving device and two vehicle detectors are required.

  In contrast, the vehicle detector according to the fifteenth embodiment of the present invention can calculate the speed of the vehicle 10 alone based on the result of the magnetic field measurement performed by itself. For this reason, the cost concerning introduction of a vehicle sensing system can be held down, for example.

  In the vehicle detector according to the fifteenth embodiment of the present invention, the predetermined condition is that the magnitude of the magnetic field rises from a state where it converges to a predetermined value or a predetermined range and reaches a peak value. .

  With such a configuration, for example, a portion that generates a strong magnetic field in the vehicle can acquire the timing at which the vehicle sensor 211 comes closest to the vehicle detector 211. For example, the peak value is reached after the magnitude of the magnetic field starts to increase. The speed of the vehicle can be calculated based on the time taken until.

  In the vehicle detector according to the fifteenth embodiment of the present invention, the speed calculation unit 93 estimates the position of the specific unit, that is, the strong magnetic field unit 16 in the vehicle 10 based on the timing acquired by the acquisition unit 92. . Then, the speed calculation unit 93 calculates the speed Vs of the vehicle 10 based on the timing acquired by the acquisition unit 92 and the estimated position of the strong magnetic field unit 16.

  With such a configuration, for example, it is possible to estimate the distance between the tip of the vehicle and the portion that generates a strong magnetic field in the vehicle based on the change in the magnetic field, and based on the change in the magnetic field and the estimated distance, The speed of the vehicle can be calculated. That is, for example, an accurate vehicle speed can be obtained as compared with the case where the speed is calculated on the assumption that the distance is constant regardless of the vehicle.

  Further, in the vehicle detector according to the fifteenth embodiment of the present invention, the acquisition unit 92 has a first timing and a first timing at which the magnitude of the magnetic field in a state where it converges to a predetermined value or a predetermined range starts to increase. After that, the second timing when the magnitude of the magnetic field reaches the peak value and the third timing when the magnitude of the magnetic field decreases and converges to a predetermined value or a predetermined range after the second timing are acquired. The speed calculation unit 93 estimates the position of the strong magnetic field unit 16 in the vehicle 10 based on the second timing and the third timing acquired by the acquisition unit 92. The speed calculation unit 93 calculates the speed Vs of the vehicle 10 based on the first timing and the second timing acquired by the acquisition unit 92 and the estimated position of the strong magnetic field unit 16.

  With such a configuration, it is possible to obtain a more accurate vehicle speed by paying attention to a plurality of timings acquired based on changes in the magnetic field. Specifically, for example, first, the time taken from when the magnitude of the magnetic field started to reach the peak value and the time taken from when the magnitude of the magnetic field began to rise until it returned to the original value or range. Whether the vehicle is a large vehicle or the like is estimated based on the ratio. Next, the distance between the front end portion of the vehicle and the portion that generates a strong magnetic field in the vehicle is estimated based on an estimation result such as whether or not the vehicle is a large vehicle. Then, by dividing the estimated distance by the time taken to reach the peak value from the time when the magnitude of the magnetic field started to change, a more accurate vehicle speed can be calculated.

  In the vehicle detector according to the fifteenth embodiment of the present invention, the storage unit 85 stores information indicating the position of the strong magnetic field unit 16 in the vehicle 10. The speed calculation unit 93 calculates the speed Vs of the vehicle 10 based on the timing acquired by the acquisition unit 92 and the position of the strong magnetic field unit 16 indicated by the information stored in the storage unit 85.

  With such a configuration, for example, the distance between the front end portion of the vehicle and a portion that generates a strong magnetic field in a general vehicle can be stored in the storage unit 85, so that the distance is calculated and processed. Can get without. Then, the speed of the vehicle can be easily calculated based on the change in the magnetic field and the distance acquired from the storage unit 85.

  Further, in the vehicle detector according to the fifteenth embodiment of the present invention, the acquisition unit 92 reduces the magnitude of the magnetic field after the second timing when the magnitude of the magnetic field reaches the peak value and after the second timing. A third timing for convergence to a predetermined value or a predetermined range is acquired. The vehicle length calculation unit 94 calculates a vehicle length Dm that is the length of the vehicle 10 based on the speed calculated by the speed calculation unit 93 and the third timing acquired by the acquisition unit 92.

  With such a configuration, for example, the length of the vehicle can be calculated by multiplying the speed of the vehicle by the time taken from when the magnitude of the magnetic field starts to rise to return to the original value or range.

  In the vehicle detector according to the fifteenth embodiment of the present invention, the determination unit 95 determines the type of the vehicle 10, that is, the vehicle type of the vehicle 10, based on the vehicle length Dm calculated by the vehicle length calculation unit 94. To do.

  With such a configuration, for example, the vehicle can be classified into one of a large vehicle, a medium vehicle, and a small vehicle according to the length of the vehicle.

  Moreover, the vehicle detector according to the fifteenth embodiment of the present invention operates using electric power stored in the battery included in the battery unit 89. The sleep control unit 87 operates at least one of the speed calculation unit 93 and the acquisition unit 92 intermittently. Then, after stopping the operation of at least one of the speed calculation unit 93 and the acquisition unit 92, the sleep control unit 87 stops at least the speed calculation unit 93 and the acquisition unit 92 when the predetermined condition is satisfied. Resume one of the operations.

  With such a configuration, for example, when the vehicle does not pass by the vehicle detector 211 for a predetermined period of time, the operations of the speed calculation unit 93 and the acquisition unit 92 are stopped, and when the vehicle approaches the vehicle detector 211, the speed is increased. An intermittent operation such as resuming the operations of the calculation unit 93 and the acquisition unit 92 can be performed. As a result, the battery power consumption by the vehicle detector 211 can be suppressed, and for example, the battery replacement frequency can be reduced. In particular, when the vehicle sensor 211 with a built-in battery or a single battery is embedded under the road surface, the maintenance cost of the vehicle sensor 211 such as battery replacement work can be effectively reduced.

  In the vehicle detector according to the fifteenth embodiment of the present invention, the communication unit 83 transmits vehicle information indicating the speed of the vehicle 10 calculated by the speed calculation unit 93 to the receiving device 212. The communication unit 83 transmits the vehicle information to the receiving device 212 when the vehicle detector 211 receives the notification that the vehicle information can be received or the vehicle information transmission instruction from the receiving device 212.

  With such a configuration, for example, when a plurality of vehicle detectors 211 are installed for one receiving device 212, each vehicle detector 211 transmits vehicle information at a different timing from the other vehicle detectors 211. Therefore, collision of radio waves transmitted from each vehicle detector 211 can be avoided. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of the vehicle information by the vehicle detector 211 can be reduced, and consumption of electric power can be suppressed.

  In the vehicle detector according to the fifteenth embodiment of the present invention, the communication unit 83 repeatedly transmits vehicle information, and the vehicle detector 211 receives a notification that reception of vehicle information is completed. When receiving from 212, transmission of vehicle information is stopped.

  With such a configuration, for example, even when the state of the transmission path between the vehicle detector 211 and the receiving device 212 is bad, the vehicle information can be transmitted to the receiving device 212 more reliably.

  In the vehicle detection system according to the fifteenth embodiment of the present invention, the monitoring unit 88 in the vehicle detector 211 monitors a change in the magnetic field. The acquisition unit 92 acquires the timing at which the change of the magnetic field satisfies a predetermined condition based on the monitoring result of the monitoring unit 88. The speed calculation unit 93 calculates the speed Vs of the vehicle 10 based on the timing acquired by the acquisition unit 92. The communication unit 83 transmits vehicle information indicating the speed Vs calculated by the speed calculation unit 93 to the receiving device 212. The receiving device 212 creates comprehensive vehicle information based on the vehicle information received from each vehicle sensor 211.

  As described above, the influence of the surrounding environment can be suppressed by the configuration using the magnetic field. In addition, from the change in the magnetic field, not only information on whether or not the vehicle has passed by the vehicle detector 211 but also information on the speed of the vehicle can be acquired. Further, in the receiving device 212, the information acquired by each vehicle detector 211 can be aggregated to create more accurate information of the vehicle that has passed by the vehicle detector 211, which facilitates detailed traffic conditions. Can grasp. Compared to a vehicle sensing system that measures the speed of a vehicle using radio waves, a configuration for transmitting and receiving radio waves used for vehicle sensing is not necessary, and a change in magnetic field can be detected with a single configuration. The speed of the vehicle can be obtained with a simpler configuration.

  Since other configurations and operations are similar to those of the vehicle sensing system according to the first embodiment, detailed description thereof will not be repeated here.

<Sixteenth Embodiment>
The present embodiment relates to a vehicle sensing system in which the vehicle detector transmits a vehicle information to a receiving device, as compared with the vehicle sensing system according to the fifteenth embodiment. The contents other than those described below are the same as those of the vehicle sensing system according to the fifteenth embodiment.

  FIG. 38 is a diagram showing a configuration of the vehicle sensing system according to the sixteenth embodiment of the present invention.

  With reference to FIG. 38, the vehicle sensing system 116 includes a vehicle detector 211, a receiving device 212, and a synchronization processing unit 239.

  The synchronization processing unit 239 performs processing for synchronizing the receiving device 212 and each vehicle sensor 211 by transmitting and receiving time information between the receiving device 212 and the plurality of vehicle detectors 211.

  The synchronization processing unit 239 may be included in the vehicle sensor 211, the reception device 212, or a device other than the vehicle sensor 211 and the reception device 212 (hereinafter also referred to as a synchronization device). You may have. In addition, the synchronization processing unit 239 may be included in both the vehicle detector 211 and the reception device 212, or may be included in the vehicle detector 211, the reception device 212, and the synchronization device.

  Hereinafter, the synchronization processing unit 239 included in the vehicle detector 211 is referred to as a synchronization processing unit 239A, the synchronization processing unit 239 included in the reception device 212 is referred to as a synchronization processing unit 239B, and the synchronization processing unit 239 included in the synchronization device is also referred to as a synchronization processing unit 239C. .

  For example, when the vehicle sensor 211 and the reception device 212 include the synchronization processing unit 239, the synchronization processing unit 239B in the reception device 212 creates radio time information that is time information indicating the current time according to its own internal clock. It transmits to each vehicle sensor 211.

  The synchronization processing unit 239A in each vehicle sensor 211 corrects the time of the internal clock in its own vehicle sensor 211 based on the radio time information from the reception device 212, and the reception device 212 and its own vehicle sensor. 211 is synchronized.

  In addition, for example, when the vehicle detector 211, the receiving device 212, and the synchronization device all include the synchronization processing unit 239, the synchronization processing unit 239C in the synchronization device is a synchronization device that is time information indicating the current time according to its own internal clock. Time information is created and transmitted to each vehicle sensor 211 and receiving device 212.

  The synchronization processing unit 239A in each vehicle sensor 211 corrects the time of the internal clock in its own vehicle sensor 211 based on the synchronization device time information from the synchronization device, and the synchronization device and its own vehicle sensor 211 are connected. Synchronize.

  The synchronization processing unit 239B in the receiving device 212 corrects the time of the internal clock in the own receiving device 212 based on the synchronizing device time information from the synchronizing device, and synchronizes the synchronizing device and the own receiving device 212. Thereby, each vehicle sensor 211 and the receiving device 212 are synchronized with each other.

  Each vehicle detector 211 transmits vehicle information to the receiving device 212 at a predetermined time for each vehicle detector 211.

  Based on the time when the vehicle information is received, the reception device 212 recognizes the vehicle detector 211 that is the transmission source of the vehicle information. Since the vehicle detector 211 and the receiving device 212 are synchronized, the receiving device 212 can accurately recognize the vehicle detector 211 that is the transmission source of the vehicle information.

  In addition, the synchronization processing unit 239 in the apparatus on the time information transmission side periodically creates and transmits time information, for example. For example, the synchronization processing unit 239 in the time information receiving side device stops operating except for the time zone in which the receiving side device receives the time information, and in the time zone in which the receiving side device receives the time information. Resume operation. Thus, power consumption in the receiving device can be suppressed.

  Note that the synchronization processing unit 239 is not limited to a configuration that synchronizes the time of the reception device 212 and each vehicle detector 211, and may be a configuration that adjusts the elapsed time from the reference time, such as frame synchronization.

  As described above, in the vehicle detection system according to the sixteenth embodiment of the present invention, the synchronization processing unit 239 transmits and receives time information between the reception device 212 and each vehicle detector 211, thereby receiving the reception device 212 and The process which synchronizes each vehicle sensor 211 is performed.

  With such a configuration, for example, each vehicle detector 211 transmits vehicle information at a different timing from the other vehicle detectors 211 by transmitting vehicle information at a time determined for each vehicle detector 211. Therefore, it is possible to avoid collision of sensing radio waves transmitted by each vehicle sensor 211. Moreover, since vehicle information should just be transmitted in a specific timing, the frequency | count of transmission of vehicle information can be reduced and consumption of electric power can be suppressed.

  Since other configurations and operations are the same as those of the vehicle sensing system according to the fifteenth embodiment, detailed description thereof will not be repeated here.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The above description includes the following features.

[Appendix 1]
An antenna for receiving radio waves transmitted from other devices;
A vehicle information creation unit that measures the radio waves received by the antenna and creates vehicle information related to the vehicle based on a change in measurement results;
The antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops,
The vehicle information creation unit is a vehicle detector that creates the vehicle information indicating part or all of the speed, vehicle length, vehicle type, and traveling direction of the vehicle.

[Appendix 2]
A radio wave transmitted from a transmission device that is embedded under a road surface through which a vehicle passes or under a road surface through which the vehicle stops, or a road surface antenna that is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops. Measuring antenna to receive,
A vehicle information creation unit that measures the radio waves received by the measurement antenna and creates vehicle information related to the vehicle based on a change in measurement results;
The measurement antenna is installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops,
The vehicle information creation unit is a vehicle detector that creates the vehicle information indicating part or all of the speed, vehicle length, vehicle type, and traveling direction of the vehicle.

[Appendix 3]
A receiving device;
One or more vehicle detectors,
The vehicle sensor is
An antenna for receiving radio waves transmitted from a device other than the vehicle detector;
A vehicle information creation unit that measures the radio waves received by the antenna and creates vehicle information related to the vehicle based on a change in measurement results;
A communication unit that transmits the vehicle information to the receiving device,
The antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops,
The receiving device creates comprehensive vehicle information based on the vehicle information received from each of the vehicle detectors,
The vehicle information creating unit is a vehicle sensing system that creates the vehicle information indicating a part of or all of a speed, a vehicle length, a vehicle type, and a traveling direction of the vehicle.

[Appendix 4]
A transmission device comprising a road surface side antenna that is embedded under a road surface through which a vehicle passes or under a road surface through which the vehicle stops, or is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops;
A vehicle sensor,
The vehicle sensor is
A measurement antenna for receiving radio waves transmitted from the road surface antenna;
A vehicle information creation unit that measures the radio waves received by the measurement antenna and creates vehicle information related to the vehicle based on a change in measurement results;
The measurement antenna is installed above the road surface on which the vehicle passes or above the road surface on which the vehicle stops,
The vehicle information creating unit is a vehicle sensing system that creates the vehicle information indicating a part of or all of a speed, a vehicle length, a vehicle type, and a traveling direction of the vehicle.

[Appendix 5]
A monitoring unit that monitors changes in the magnetic field;
An acquisition unit that acquires a timing at which the change in the magnetic field satisfies a predetermined condition based on a monitoring result of the monitoring unit;
A speed calculation unit that calculates the speed of the vehicle based on the timing acquired by the acquisition unit;
The monitoring unit monitors a change in the magnetic field accompanying the traveling of the vehicle using a geomagnetic sensor,
A vehicle detector embedded in a road surface through which the vehicle passes, or installed on a road surface through which the vehicle passes or a side of a road through which the vehicle passes.

[Appendix 6]
A receiving device;
One or more vehicle detectors,
The vehicle sensor is
A monitoring unit that monitors changes in the magnetic field;
An acquisition unit that acquires a timing at which the change in the magnetic field satisfies a predetermined condition based on a monitoring result of the monitoring unit;
Based on the timing acquired by the acquisition unit, a speed calculation unit that calculates the speed of the vehicle,
A communication unit that transmits vehicle information indicating the speed calculated by the speed calculation unit to the receiving device;
The receiving device creates comprehensive vehicle information based on the vehicle information received from each of the vehicle detectors,
The monitoring unit monitors a change in the magnetic field accompanying the traveling of the vehicle using a geomagnetic sensor,
The vehicle sensor system is embedded in a road surface through which the vehicle passes, or is installed on a road surface through which the vehicle passes or a side of a road through which the vehicle passes.

DESCRIPTION OF SYMBOLS 10 Vehicle 11,21,211 Vehicle detector 12 Radio | wireless machine 13,30,31,41,51,71,82 Antenna 14 Road 15 Existing radio | wireless machine 16 Strong magnetic field part 22 Transmitter 32,52,72,83 Communication part 33 , 53, 90 Vehicle information creation unit 34, 74, 87 Sleep control unit 35, 55, 75, 84 Management unit 36, 56, 76, 85 Storage unit 37, 77, 89 Battery unit 38, 78, 86 Magnetic sensor 39, 239 Synchronization processing unit 40 Transmitting unit 45 Vehicle detector body 57 Vehicle detector body 73 Detected radio wave transmission unit 88 Monitoring unit 92 Acquisition unit 93 Speed calculation unit 94 Vehicle length calculation unit 95 Discrimination unit 101, 105, 106, 107, 108, 110, 111, 112, 113, 114, 115 Vehicle sensing system 212 Receiver

Claims (20)

An antenna for receiving radio waves transmitted from other devices;
A vehicle information creation unit that measures the radio waves received by the antenna and creates vehicle information related to the vehicle based on a change in measurement results;
The antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops,
The vehicle information creation unit is a vehicle detector that creates the vehicle information based on the measured reception level and measurement time.   The vehicle information creation unit creates the vehicle information indicating at least one of the speed, the vehicle length, the vehicle type, and the traveling direction of the vehicle based on the measured reception level and the measurement time. The vehicle detector according to claim 1.   The vehicle detector according to claim 1, wherein the vehicle information creation unit creates the vehicle information based on a transition time during which the reception level is transitioned.   The vehicle detector according to claim 3, wherein the vehicle information creation unit creates the vehicle information based on the transition time and the time when the reception level is lowered and becomes a constant value.   The vehicle detector according to any one of claims 1 to 4, wherein the vehicle information creation unit creates the vehicle information based on a peak value reached when the reception level increases. The vehicle sensor operates using electric power stored in a battery,
The vehicle detector further includes a sleep control unit that intermittently operates the vehicle information creation unit,
The said sleep control part restarts operation | movement of the said vehicle information preparation part, when predetermined conditions are satisfy | filled after stopping the operation | movement of the said vehicle information preparation part. Vehicle detector. The vehicle detector further includes a communication unit that transmits the vehicle information to a receiving device,
The communication unit transmits the vehicle information to the receiving device when the vehicle detector receives a notification that the vehicle information can be received or an instruction to transmit the vehicle information from the receiving device. The vehicle detector according to any one of claims 1 to 6.   The communication unit repeatedly transmits the vehicle information, and stops the transmission of the vehicle information when the vehicle detector receives a notification that the reception of the vehicle information is completed from the receiving device. The vehicle sensor according to claim 7.   9. The radio wave according to claim 1, wherein the radio wave is a radio wave transmitted from a transmitter that transmits a radio wave in order to communicate with a radio other than the vehicle sensor. 10. Vehicle detector. The vehicle sensor further includes:
A communication unit that communicates with the other device by transmitting and receiving signals to and from the other device via the antenna;
The vehicle information creation unit creates the vehicle information based on a change in the measurement result and whether or not a signal transmitted from the other device can be received by the communication unit. The vehicle detector according to claim 1. A radio wave transmitted from a transmission device that is embedded under a road surface through which a vehicle passes or under a road surface through which the vehicle stops, or a road surface antenna that is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops. Measuring antenna to receive,
A vehicle information creation unit that measures the radio waves received by the measurement antenna and creates vehicle information related to the vehicle based on a change in measurement results;
The measurement antenna is installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops,
The vehicle information creation unit is a vehicle detector that creates the vehicle information based on the measured reception level and measurement time. The vehicle sensor further includes:
A communication unit that communicates with the transmission device by transmitting and receiving signals to and from the transmission device via the measurement antenna;
The vehicle detector according to claim 11, wherein the vehicle information creation unit creates the vehicle information based on a change in the measurement result and whether the communication unit can receive a signal transmitted from the transmission device. A vehicle detector,
An antenna for receiving radio waves transmitted from other devices;
A magnetic sensor for measuring a magnetic field in the vehicle sensor;
A vehicle detector comprising: a vehicle information creation unit that measures the radio wave received by the antenna and creates vehicle information related to the vehicle based on the measurement result of the radio wave and the measurement result of the magnetic field. A receiving device;
One or more vehicle detectors,
The vehicle sensor is
An antenna for receiving radio waves transmitted from a device other than the vehicle detector;
A vehicle information creation unit that measures the radio waves received by the antenna and creates vehicle information related to the vehicle based on a change in measurement results;
A communication unit that transmits the vehicle information to the receiving device,
The antenna is embedded under a road surface through which the vehicle passes or under a road surface through which the vehicle stops, or is installed on a road surface through which the vehicle passes or a road surface through which the vehicle stops,
The receiving device creates comprehensive vehicle information based on the vehicle information received from each of the vehicle detectors,
The vehicle information creation unit creates the vehicle information based on the measured reception level and measurement time. The vehicle sensing system further includes:
The vehicle detection system according to claim 14, further comprising a synchronization processing unit that performs processing of synchronizing the reception device and each vehicle sensor by transmitting and receiving time information between the reception device and each vehicle sensor. A transmitter including a road surface antenna that is embedded under a road surface through which the vehicle passes or under a road surface where the vehicle stops, or is installed on a road surface through which the vehicle passes or a road where the vehicle stops;
A vehicle sensor,
The vehicle sensor is
A measurement antenna for receiving radio waves transmitted from the road surface antenna;
A vehicle information creation unit that measures the radio waves received by the measurement antenna and creates vehicle information related to the vehicle based on a change in measurement results;
The measurement antenna is installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops,
The vehicle information creation unit creates the vehicle information based on the measured reception level and measurement time. The transmitter operates using power stored in a battery,
The transmitter is
A sensing radio wave transmission unit that transmits the radio wave using the road surface antenna;
A sleep control unit that intermittently operates the sensing radio wave transmission unit,
The vehicle detection system according to claim 16, wherein the sleep control unit resumes the operation of the sensing radio wave transmission unit when a predetermined condition is satisfied after the operation of the sensing radio wave transmission unit is stopped. The vehicle sensor further includes:
A communication unit that communicates with the transmission device by transmitting and receiving signals to and from the transmission device via the measurement antenna;
The vehicle information creation unit creates the vehicle information based on a change in the measurement result and whether the communication unit can receive a signal transmitted from the transmission device. Vehicle sensing system. A receiving device;
One or more vehicle detectors,
The vehicle sensor is
An antenna for receiving radio waves transmitted from a device other than the vehicle detector;
A magnetic sensor for measuring a magnetic field in the vehicle sensor;
A vehicle information creation unit that measures the radio wave received by the antenna and creates vehicle information related to the vehicle based on the measurement result of the radio wave and the measurement result of the magnetic field;
A communication unit that transmits the vehicle information to the receiving device,
The receiving device creates comprehensive vehicle information based on the vehicle information received from each of the vehicle detectors. A transmitter including a road surface antenna that is embedded under a road surface through which the vehicle passes or under a road surface where the vehicle stops, or is installed on a road surface through which the vehicle passes or a road where the vehicle stops;
A vehicle sensor,
The vehicle sensor is
A measurement antenna for receiving radio waves transmitted from the road surface antenna;
A magnetic sensor for measuring a magnetic field in the vehicle sensor;
A vehicle information creation unit that measures the radio wave received by the measurement antenna and creates vehicle information related to the vehicle based on the measurement result of the radio wave and the measurement result of the magnetic field;
The measurement antenna is a vehicle sensing system installed above a road surface on which the vehicle passes or above a road surface on which the vehicle stops.

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