JP2012084064A - Wireless tag system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and surely collect measurement data of a maintenance/monitor target, by extending a maximum response time in a tag between the tag installed on the maintenance/monitor target such as a manhole embedded in the underground under a road and a reader installed in a vehicle travelling on the road above the maintenance/monitor target.SOLUTION: As for the reader, a reader transmission part 11 for transmitting a start signal is installed forward of the moving direction of a moving body 1 and a reader reception part 12 for receiving a response signal is installed backward of the moving direction of the moving body 1. As for the tag, a tag reception part 21 for receiving the start signal is installed on the front of the moving direction of the moving body 1, a tag transmission part 22 for transmitting the response signal is installed on the end of the moving direction of the moving body 1, and the tag transmission part 22 transmits the response signal in response to a reception notification of the start signal from the tag reception part 21. The tag has a control means for storing analysis data of measurement data including measurement of a state of the maintenance/monitor target 5, reading out the analysis data in response to the reception notification of the start signal and transmitting it as the response signal.

Description

  The present invention relates to a wireless tag system for exchanging information by a wireless signal between a reader and a tag at least one of which moves.

  For example, a tag that collects maintenance monitoring information in a manhole and a reader mounted on a vehicle that passes on a road with a manhole, and the manhole collected by the tag with respect to a reader of a vehicle that passes in the vicinity of the manhole The present invention relates to a wireless tag system that transmits maintenance monitoring information.

FIG. 13 shows a first configuration example of a conventional wireless tag system (Patent Document 1).
In FIG. 13, for example, a tag 6 including a sensor 62 that measures the state of a maintenance monitoring target 5 such as a bridge receives an activation signal transmitted from a reader 41 mounted on the vehicle 4 by a tag receiver 61. The measurement data measured by the sensor 62 using a start signal as a trigger is transmitted from the tag transmitter 64 as a response signal, and the reader 41 of the vehicle 4 receives the response signal. Here, the tag receiver 61 and the tag transmitter 64 are installed apart from both ends of the maintenance monitoring target 5 along the traveling direction of the vehicle 4, and the timing at which the vehicle 4 passes through each communication area is maintained. There is a time lag according to the length of the monitoring object 5.

  The tag 6 includes a tag receiver 61, a sensor 62, a measurement result storage device 63, a tag transmitter 64, and a timer 65. When the tag receiver 61 receives the activation signal, it notifies the sensor 62, the measurement result storage device 63, the tag transmitter 64, and the timer 65 of the activation control signal. The sensor 62 measures the state of the maintenance monitoring object 5 according to the activation control signal, and outputs the measurement data to the measurement data storage device 63 and the tag transmitter 64. The measurement data storage device 63 stores the measurement data output from the sensor 62 in response to the activation control signal. The timer 65 notifies the tag transmitter 64 of the transmission timing corresponding to the time lag from the input of the activation control signal, and the tag transmitter 64 reads the measurement data stored in the measurement data storage device 63 at the notified transmission timing, Send as response signal. Thereby, the sensor 62 measures the state of the maintenance monitoring object 5 while the vehicle 4 passes through the maintenance monitoring object 5, and the measurement data at the timing when the vehicle 4 passes the communication area of the tag transmitter 64. Can receive.

JP 2009-295051 A

  Incidentally, the maintenance monitoring object 5 shown in FIG. 13 is a relatively long object such as a bridge, and the time required for the vehicle 4 equipped with the reader 41 to pass through the maintenance monitoring object 5 is also relatively long. Therefore, it is possible to secure a sufficient time for measuring the state of the maintenance monitoring target 5 by the tag 6 and further for transmitting the measurement data from the tag 6 to the reader 41 as a response signal.

  However, as shown in FIG. 14, when the maintenance monitoring object 5 is a manhole or the like, the vehicle 4 travels on a general road with a manhole, and wirelessly collects measurement data measured by a tag sensor 62 installed in the manhole. The tag system has the following problems.

  The maintenance monitoring target 5 in FIG. 14 has the same configuration as the tag 6 shown in FIG. 13, but only the tag receiver 61, tag transmitter 64, and sensor 62 are schematically shown here. In general, the distance between the tag receiver 61 and the tag transmitter 64 installed in the manhole is about several meters, and the reach of the activation signal transmitted by the reader 41 and the response signal transmitted by the tag transmitter 64 (the radio wave reaches). The distance) is also about several meters. For this reason, the start signal transmitted by the reader 41 of the vehicle 4 is received by the tag receiver 61 and the response signal transmitted by the tag transmitter 64 can be received by the reader 41 is a communication distance (travel distance of the vehicle 4) of several tens of meters. Degree. That is, in the meantime, the sensor 62 needs to measure the state of the maintenance monitoring object 5, process the measurement data, and transmit it as a response signal from the tag transmitter 64.

Here, as shown in FIG. 14, the maximum reach distance of the activation signal transmitted by the reader 41 is L1 (m), the maximum reach distance of the response signal transmitted by the tag transmitter 64 is L2 (m), and the tag receiver 61. And the tag transmitter 64 is Lm (m), and the speed of the vehicle 4 is V (m / sec). At this time, the maximum response time allowed from when the tag receiver 61 receives the activation signal to when the tag transmitter 64 transmits the response signal is:
(L1 + Lm + L2) / V (seconds)
It becomes.

  For example, if L1 = 2 m, L2 = 7 m, Lm = 5 m, V = 16.7 m / sec (= 60 km / hr), the maximum response time of the tag is (2 + 5 + 7) /16.7=0.84 sec, and the tag transmitter 64 May transmit a response signal within the maximum response time. For example, when the transmission cycle of the activation signal is 2 milliseconds (travel distance is 3.3 cm), the propagation time of the activation signal and the response signal is such that the distance between the reader 41 and the tag receiver 61 is L1 or less. Ignoring.

  Further, in the case of a tag in which the tag receiver 61 and the tag transmitter 64 are integrated, the interval Lm between the tag receiver 61 and the tag transmitter 64 is 0 m. The maximum response time that can be secured before transmission is further shortened to (2 + 7) /16.7=0.54 seconds.

  However, in order to measure the state of the maintenance monitoring object 5 within 0.84 seconds or 0.54 seconds of the maximum response time after receiving the activation signal in this way, process the measurement data, and transmit it as a response signal. When high-speed processing is required and the maintenance monitoring object 5 is a manhole, the response signal may not be transmitted in time. Alternatively, it is necessary to significantly slow down the traveling speed of the vehicle 4, and there are significant restrictions in operating on a general road with a manhole.

  The present invention extends the maximum response time in a tag between a tag installed on a maintenance monitoring target such as a manhole buried under a road and a reader installed on a vehicle traveling on a road on the maintenance monitoring target, An object of the present invention is to provide a wireless tag system capable of efficiently and reliably collecting measurement data of a maintenance monitoring object.

  The present invention comprises a tag installed on an object to be monitored and a reader installed on a moving body that passes in the vicinity of the object to be monitored, and transmits an activation signal from the reader at a predetermined cycle, In a wireless tag system in which a response signal is transmitted from a tag that has received the signal and the response signal is received by the reader, the reader places a reader transmission unit that transmits an activation signal in front of the moving body, and transmits the response signal. The reader receiving unit for receiving is installed behind the moving direction of the moving body, and the tag has a tag receiving unit for receiving an activation signal in front of the moving direction of the moving body, and a response signal ahead of the moving body in the moving direction. The tag transmission unit is configured to transmit a response signal in response to the reception notification of the activation signal from the tag reception unit, and the tag further includes measurement data obtained by measuring the state of the maintenance monitoring target. It analyzes, stores the analysis data, a control means for transmitting a response signal reads the analysis data in response to receiving notification of the start signal.

  In the wireless tag system of the present invention, there are at least two maintenance monitoring objects on the moving path of the moving body, a tag receiving unit is installed on the first maintenance monitoring object before the moving direction of the moving body, and the moving body moves The tag transmission unit is installed in the second maintenance monitoring target in the direction, and the reception signal of the activation signal is sent from the tag reception unit to the tag transmission unit via the cable. The analysis data corresponding to the state of at least one of the maintenance monitoring object and the second maintenance monitoring object is transmitted as a response signal.

  In the wireless tag system of the present invention, the tag receiving unit of the tag is installed in front of the moving object away from the object to be monitored and the activation signal is notified from the tag receiving unit to the tag transmitting unit via the cable. It is a configuration.

  In the wireless tag system of the present invention, the moving body is composed of at least two units that move at a predetermined interval, the reader transmitting unit is installed on the first moving body on the front side, and the second moving body on the rear side is installed. The reader receiving unit is installed.

  In the wireless tag system of the present invention, the tag transmission unit determines the timing when the tag transmission unit and the reader reception unit can communicate with each other after receiving the activation signal reception notification, and transmits the response signal at the timing. Transmission timing control means for starting is provided.

  In the wireless tag system of the present invention, the moving body is composed of at least two units that move at a predetermined interval, the reader transmitting unit is installed on the first moving body on the front side, and the second moving body on the rear side is installed. The reader receiving unit is installed, and the tag transmitting unit can communicate with the tag transmitting unit and the reader receiving unit after receiving an activation signal reception notification due to the time difference between the first moving body and the second moving body. A transmission timing control means is provided for determining the timing of the positional relationship and starting transmission of the response signal at the timing.

  The first moving body and the second moving body may be realized by a single moving body that moves at a predetermined time difference.

  In the wireless tag system of the present invention, the reader receiving unit is configured to include two receiving means for receiving a response signal and means for diversity combining the received signals.

  In the wireless tag system of the present invention, the tag transmitter is configured to repeatedly transmit a response signal at a predetermined transmission cycle.

  The wireless tag system of the present invention extends the maximum response time until the tag transmission unit transmits a response signal by the interval by arranging the reader transmission unit and the reader reception unit separately before and after the moving body. Can do.

  Further, the tag control means stores the measurement data indicating the state of the maintenance monitoring object as compact analysis data, and transmits it as a response signal, thereby responding from the activation signal reception to the response signal transmission. Can significantly reduce the response time required. As a result, for example, maintenance monitoring analysis data such as manholes can be reliably acquired while the vehicle is running.

It is a figure which shows the structural example of the wireless tag system of Example 1 of this invention. 1 is a diagram illustrating a configuration example of a reader in a wireless tag system according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration example of a tag in a wireless tag system according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating an example of an operation sequence of the wireless tag system according to the first embodiment. It is a figure which shows the structural example of the wireless tag system of Example 2 of this invention. It is a figure which shows the structural example of the radio | wireless tag system of Example 3 of this invention. It is a figure which shows the structural example 1 of the wireless tag system of Example 4 of this invention. It is a figure which shows the structural example 2 of the wireless tag system of Example 4 of this invention. It is a figure which shows the other structural example of the tag in the radio | wireless tag system of this invention. It is a figure which shows the structural example of the wireless tag system of Example 6 of this invention. It is a figure which shows the structural example of the wireless tag system of Example 7 of this invention. It is a figure explaining the beam tilt antenna effect of the radio | wireless tag system of Example 7 of this invention. It is a figure which shows the 1st structural example of the conventional radio | wireless tag system. It is a figure which shows the 2nd structural example of the conventional wireless tag system.

FIG. 1 shows a configuration example of a wireless tag system according to a first embodiment of the present invention.
In FIG. 1, a reader mounted on a vehicle 1 includes a reader transmission unit (T) 11 that transmits an activation signal to the tag at a predetermined cycle, and a reader reception unit (R) 12 that receives a response signal from the tag. Are separated from each other, the reader transmitter (T) 11 is installed in the front of the vehicle, and the reader receiver (R) 12 is installed in the rear of the vehicle. For example, a tag installed on the maintenance monitoring target 5 such as a manhole includes a tag receiving unit 21 that receives an activation signal, a tag transmission unit 22 that transmits a response signal, and a sensor 23 that measures the state of the maintenance monitoring target 5. Is provided. The tag receiving unit 21 and the tag transmitting unit 22 are arranged separately according to the traveling direction of the vehicle 1. Alternatively, the traveling direction of the vehicle 1 is determined in the arrangement order of the tag receiving unit 21 and the tag transmitting unit 22.

  The first feature of the present invention resides in that the reader transmitter (T) 11 is installed in the front of the vehicle and the reader receiver (R) 12 is installed in the rear of the vehicle. The second feature of the present invention is that in the tag, the sensor 23 that operates asynchronously with the activation signal from the reader and the analysis data obtained by analyzing the measurement data are stored, and the analysis data according to the activation signal from the reader is stored. Is provided as a response signal. The detailed configuration of the reader and tag will be described separately.

  The activation signal transmitted from the reader transmission unit (T) 11 at the front of the vehicle is received by the tag reception unit 21 and notified to the tag transmission unit 22 as an activation control signal. On the other hand, the tag transmission unit 22 sequentially inputs measurement data from the sensor 23, analyzes the measurement data and stores it as analysis data, and transmits the analysis data stored according to the activation control signal as a response signal. . The response signal transmitted from the tag transmitter 22 is received by the reader receiver (R) 12 at the rear of the vehicle.

Here, as shown in FIG. 1, the maximum reach distance of the activation signal transmitted by the reader transmitter (T) 11 is L1 (m), and the maximum reach distance of the response signal transmitted by the tag transmitter 22 is L2 (m). , The distance (manhole length) between the tag receiver 21 and the tag transmitter 22 is Lm (m), and the distance between the reader receiver (R) 12 of the vehicle 1 and the transmitter (T) 11 (length of the vehicle 1). Is Lc (m), and the speed of the vehicle 1 is V (m / sec). At this time, the maximum response time allowed from when the tag receiving unit 21 receives the activation signal to when the tag transmitting unit 22 transmits the response signal is:
(Lc + L1 + Lm + L2) / V (second)
It becomes. For example, if L1 = 2m, L2 = 7m, Lm = 5m, Lc = 4m, V = 16.7m / second (= 60km / hour), the maximum response time of the tag is 1.08 seconds, and the tag transmitter 22 is controlled to start. What is necessary is just to transmit a response signal within this maximum response time after inputting a signal. The maximum response time will be 29% longer than the conventional 0.84 seconds. In addition, when the position where the reader transmission unit (T) 11 transmits the activation signal falls within L1 according to the transmission cycle (the transmission cycle is 3.3 cm at the maximum with 2 milliseconds), the propagation time of the activation signal and the response signal Is ignored.

  The sections Lc, L1, Lm, and L2 shown in FIG. 1 are schematically shown and do not necessarily match the magnitudes of the above numerical examples. The same applies to the embodiments described below.

  As described above, since the reader transmission unit (T) 11 and the reader reception unit (R) 12 are separately provided before and after the vehicle 1, the maximum response time is extended by the interval Lc. Further, by connecting a timer to the tag transmission unit 22 and repeatedly transmitting the response signal at a predetermined transmission period from the input time of the activation control signal to the maximum response time + α (α is an arbitrary margin), the reader reception unit ( R) 12 can surely receive the response signal, and power transmission can be suppressed by stopping transmission of the response signal thereafter.

FIG. 2 illustrates a configuration example of a reader in the wireless tag system according to the first embodiment.
In FIG. 2, the reader transmission unit (T) 11 includes a control circuit 111 that controls a transmission cycle of the activation signal and a transmission circuit / transmission antenna 112 that transmits the activation signal. The reader receiving unit (R) 12 combines two receiving antennas / receiving circuits 121 and 122 for receiving a response signal (analysis data) transmitted from the tag, and combining / demodulating the signals by diversity combining the outputs of the receiving circuits. The circuit 123 and the data storage circuit 124 that stores the demodulated analysis data are included. In the configuration of diversity combining using two receiving circuits, the maximum reachable distance L2 of the response signal transmitted by the tag transmitting unit 22 can be extended by improving the reception characteristics, but the configuration is not necessarily limited to the configuration of diversity combining. It is not a thing.

FIG. 3 illustrates a configuration example of a tag in the wireless tag system according to the first embodiment.
In FIG. 3, the tag includes a tag receiving unit 21, a tag transmitting unit 22, and a sensor 23. The tag reception unit 21 receives the activation signal transmitted from the reader transmission unit (T) 11 by the reception antenna / reception circuit 211, generates an activation control signal, and outputs it to the tag transmission unit 22. The tag transmission unit 22 includes a transmission circuit / transmission antenna 221 and a data analysis storage circuit 222 that operate using the activation control signal as a trigger, a measurement data collection circuit 223 that inputs measurement data from the sensor 23, a measurement data collection circuit 223, and data It comprises a measurement data collection / analysis timer 224 that gives operation timing to the analysis storage circuit 222.

  The sensor 23 is a facility in the manhole, such as a water pressure sensor for detecting inundation in the manhole, an acceleration sensor or gauge sensor for detecting vibration or distortion that affects the manhole structure, or a temperature sensor for detecting the temperature in the manhole. Outputs various maintenance monitoring data used for inspection. The measurement data collection circuit 223 collects measurement data from the sensor 23 at a time interval set by the measurement data collection / analysis timer 224 and outputs it to the data analysis storage circuit 222. The data analysis storage circuit 222 stores analysis data obtained by analyzing the measurement data, and stores the analysis data stored in accordance with the activation control signal input from the tag receiver 21 to the transmission circuit / transmission antenna 221. Output. For example, the data analysis storage circuit 222 analyzes the duration (period) of the manhole inundation, analyzes the number of times the manhole shake detected by the acceleration sensor exceeds a predetermined threshold, or detects the temperature detected by the temperature sensor. Is analyzed and stored as analysis data. The transmission circuit / transmission antenna 221 transmits the analysis data as a response signal toward the reader reception unit (R) 12 in response to the activation control signal input from the tag reception unit 21. Note that, as described above, the transmission circuit / transmission antenna 221 may repeatedly transmit the response signal at a predetermined transmission cycle from the input time of the activation control signal to the maximum response time + α.

FIG. 4 illustrates an example of an operation sequence of the wireless tag system according to the first embodiment.
In FIG. 4, each part of the reader shown in FIG. 2 and the tag shown in FIG. 3 is arranged in the horizontal direction, and the vertical direction shows time. The operation sequence of the wireless tag system is stored in the tag according to the operation sequence 1 in which the tag performs from the collection of the measurement data to the storage of the analysis data in the maintenance monitoring target 5 such as a manhole, and the activation signal from the reader. It is roughly classified into an operation sequence 2 for transmitting the analyzed data to the reader.

  In the operation sequence 1, the sensor 23 periodically operates to output measurement data, the measurement data collection circuit 223 collects the measurement data, and the data analysis storage circuit 222 analyzes the measurement data and stores it as analysis data.

  In the operation sequence 2, when a vehicle equipped with a reader enters a communication area with a tag, an activation signal transmitted from the transmission circuit / transmission antenna 112 of the reader is received by the reception antenna / reception circuit 211 of the tag. When receiving the activation signal, the reception antenna / reception circuit 211 notifies the data analysis storage circuit 222 and the transmission circuit / transmission antenna 221. The data analysis storage circuit 222 reads the analysis data and outputs the analysis data to the transmission circuit 221. A response signal is transmitted from the antenna 221. The reader receiving circuits 121 and 122 and the synthesizing / demodulating circuit 123 receive and demodulate the response signal, and store the obtained analysis data in the data storage circuit 124.

  As described above, in the operation sequence 1, the data analysis storage circuit 222 analyzes the enormous measurement data measured by the sensor 23 and stores it as analysis data. As a result, in the operation sequence 2, the measurement data of the sensor 23 is not transmitted as it is as a response signal, but analysis data in which the measurement data is compacted (the duration of inundation, the number of times the shaking or temperature exceeds the threshold value) is transmitted. The response time required for the response process from the reception of the activation signal to the transmission of the response signal can be greatly shortened.

  Therefore, in this embodiment, the reader / writer (T) 11 and the reader / receiver (R) 12 are separated and installed at the front and rear of the vehicle 1, thereby extending the maximum response time and analyzing the measurement data in the tag as analysis data. By reducing the response time by converting to, it becomes possible to reliably acquire analysis data for maintenance monitoring such as manholes while driving a vehicle passing thereover.

FIG. 5 shows a configuration example of a wireless tag system according to the second embodiment of the present invention.
In FIG. 5, the feature of the second embodiment is that the tag receiving unit 21 and the tag transmitting unit 22 are not installed at both ends of one maintenance monitoring object 5, but the tags installed in different maintenance monitoring objects 5 </ b> A and 5 </ b> B, respectively. The receiving unit 21 and the tag transmitting unit 22 are connected via a cable. The maintenance monitoring objects 5 </ b> A and 5 </ b> B are assumed to be manholes that are sequentially arranged in the traveling direction of the vehicle 1.

  The activation signal transmitted from the reader transmission unit (T) 11 at the front of the vehicle is received by the tag reception unit 21 of the maintenance monitoring target 5A, and the activation control signal is notified to the tag transmission unit 22 of the maintenance monitoring target 5B. The On the other hand, the tag transmission unit 22 of the maintenance monitoring target 5B sequentially inputs measurement data from the sensor 23, analyzes the measurement data, stores it as analysis data, and responds with the analysis data stored in response to the activation control signal. Send as a signal. The maintenance monitoring target 5A is also provided with a sensor 23, and the measurement data is transmitted to the tag transmission unit 22 of the maintenance monitoring target 5B, and each of the sensors 23 of the maintenance monitoring target 5A, 5B is transmitted within the tag transmission unit 22. The measurement data may be analyzed and stored as analysis data, and the analysis data stored in response to the activation control signal may be transmitted as a response signal. In this case, the identifiers of the maintenance monitoring objects 5A and 5B are added to each analysis data. The response signal transmitted from the tag transmitter 22 is received by the reader receiver (R) 12 at the rear of the vehicle.

Here, as shown in FIG. 5, the maximum reach distance of the activation signal transmitted by the reader transmitter (T) 11 is L1 (m), and the maximum reach distance of the response signal transmitted by the tag transmitter 22 is L2 (m). The distance between the tag receiving unit 21 and the tag transmitting unit 22 (the sum of the length and interval of the two manholes) is 2Lm + Lt (m), and the interval between the reader receiving unit (R) 12 and the transmitting unit (T) 11 of the vehicle 1 is Lc. (M) Let the speed of the vehicle 1 be V (m / sec). At this time, the maximum response time allowed from when the tag receiving unit 21 receives the activation signal to when the tag transmitting unit 22 transmits the response signal is:
(Lc + L1 + 2Lm + Lt + L2) / V (seconds)
It becomes. For example, if L1 = 2m, L2 = 7m, Lm = 5m, Lt = 50m, Lc = 4m, V = 16.7m / second (= 60km / hour), the maximum response time of the tag is 4.37 seconds, and the tag transmitter 22 may transmit the response signal within the maximum response time after the activation control signal is input. Note that when the position where the reader transmission unit (T) 11 transmits the activation signal falls within L1 according to the transmission cycle, the propagation time of the activation signal and the response signal is ignored.

  Thus, by installing the tag receiving unit 21 and the tag transmitting unit 22 on the different maintenance monitoring objects 5A and 5B, the maximum response time is extended by the interval 2Lm + Lt. Further, by connecting a timer to the tag transmission unit 22 and repeatedly transmitting the response signal at a predetermined transmission period from the input time of the activation control signal to the maximum response time + α (α is an arbitrary margin), the reader reception unit ( R) 12 can surely receive the response signal, and power transmission can be suppressed by stopping transmission of the response signal thereafter.

  The maintenance monitoring target 5A may be provided with a tag transmission unit 22 and may have the same configuration as that of the tag reception unit 21 of the maintenance monitoring target 5 one before. Further, the tag receiving unit 21 may be provided in the maintenance monitoring target 5B, and the same configuration may be adopted between the maintenance monitoring target 5B and the tag transmission unit 22 of the next maintenance monitoring target 5. In addition, the tag receiving unit 21 and the tag transmitting unit 22 in the present embodiment are not limited to being installed on the adjacent maintenance monitoring objects 5, but may be installed on every other maintenance monitoring object 5, for example. In such a case, if it is necessary to specify the maintenance monitoring object 5 or the sensor 23 in which the tag transmission unit 22 for transmitting the response signal is installed, these identifiers may be added to the response signal and transmitted. . Thereby, the maintenance monitoring object 5 or the sensor 23 can be specified by the identifier of the response signal, and an unnecessary response signal can be deleted.

FIG. 6 shows a configuration example of a wireless tag system according to the third embodiment of the present invention.
In FIG. 6, the feature of the third embodiment is that the tag receiving unit 21 and the tag transmitting unit 22 are not installed at both ends of the maintenance monitoring object 5, but the tag receiving unit 21 is maintained and monitored with respect to the traveling direction of the vehicle 1. It is installed in front of the object 5, and the tag receiving unit 21 and the tag transmitting unit 22 are connected via a cable.

  The activation signal transmitted from the reader transmission unit (T) 11 at the front of the vehicle is received by the tag reception unit 21, and the activation control signal is notified to the tag transmission unit 22 of the maintenance monitoring object 5. On the other hand, the tag transmission unit 22 of the maintenance monitoring object 5 sequentially inputs measurement data from the sensor 23, analyzes the measurement data, stores it as analysis data, and responds with the analysis data stored according to the activation control signal. Send as a signal. The response signal transmitted from the tag transmitter 22 is received by the reader receiver (R) 12 at the rear of the vehicle.

Here, as shown in FIG. 6, the maximum reach distance of the activation signal transmitted by the reader transmitter (T) 11 is L1 (m), and the maximum reach distance of the response signal transmitted by the tag transmitter 22 is L2 (m). The distance between the tag receiver 21 and the tag transmitter 22 is Lm + Ls (m), the distance between the reader receiver (R) 12 and the transmitter (T) 11 of the vehicle 1 is Lc (m), and the speed of the vehicle 1 is V ( m / sec). At this time, the maximum response time allowed from when the tag receiving unit 21 receives the activation signal to when the tag transmitting unit 22 transmits the response signal is:
(Lc + L1 + Lm + Ls + L2) / V (seconds)
It becomes. For example, if L1 = 2m, L2 = 7m, Lm = 5m, Ls = 30m, Lc = 4m, V = 16.7m / second (= 60km / hour), the maximum response time of the tag is 2.87 seconds, 22 may transmit a response signal within the maximum response time after inputting the activation control signal. Note that when the position where the reader transmission unit (T) 11 transmits the activation signal falls within L1 according to the transmission cycle, the propagation time of the activation signal and the response signal is ignored.

  Thus, by installing the tag receiving unit 21 in front of the maintenance monitoring object 5, the maximum response time is extended by the interval Lm + Ls. Further, by connecting a timer to the tag transmission unit 22 and repeatedly transmitting the response signal at a predetermined transmission period from the input time of the activation control signal to the maximum response time + α (α is an arbitrary margin), the reader reception unit ( R) 12 can surely receive the response signal, and power transmission can be suppressed by stopping transmission of the response signal thereafter.

FIG. 7 shows a configuration example 1 of the wireless tag system according to the fourth embodiment of the present invention.
In FIG. 7, the feature of the fourth embodiment is that the reader transmitting unit (T) 11 and the reader receiving unit 12 are not installed at both ends of one vehicle 1, but the reader transmitting unit is installed in the vehicles 1 </ b> A and 1 </ b> B that travel back and forth. (T) 11 and reader receiving unit 12 are located separately. The vehicles 1A and 1B are assumed to travel at predetermined intervals in that order. Each of the vehicles 1A and 1B includes a reader transmission unit (T) 11 and a reader reception unit (R) 12. The vehicle 1A traveling at the head operates the reader transmission unit (T) 11, and the following vehicle 1B The reader receiving unit (R) 12 may operate. In this case, the reader transmitting unit (T) 11 and the reader receiving unit (R) 12 do not necessarily need to be installed separately at the front and rear parts of the vehicle, and may be installed integrally at the same position. Good.

  The activation signal transmitted from the reader transmission unit (T) 11 of the vehicle 1A is received by the tag reception unit 21 of the maintenance monitoring object 5, and the activation control signal is notified to the tag transmission unit 22. On the other hand, the tag transmission unit 22 sequentially inputs measurement data from the sensor 23, analyzes the measurement data and stores it as analysis data, and transmits the analysis data stored in response to the activation control signal as a response signal. The response signal transmitted from the tag transmitter 22 is received by the reader receiver (R) 12 of the vehicle 1B following the vehicle 1A.

Here, as shown in FIG. 7, the maximum reach distance of the activation signal transmitted by the reader transmitter (T) 11 is L1 (m), and the maximum reach distance of the response signal transmitted by the tag transmitter 22 is L2 (m). The distance between the tag receiver 21 and the tag transmitter 22 is Lm (m), the distance between the reader transmitter (T) 11 of the vehicle 1A and the reader receiver (R) 12 of the vehicle 1B is 2Lc + Lp (m), the vehicle 1A, The speed of 1B is set to V (m / sec). Lp is an interval between the vehicle 1A and the vehicle 1B, and Lc is an interval (vehicle length) between the reader transmission unit (T) and the reader reception unit (R) in the vehicle. At this time, the maximum response time allowed from when the tag receiving unit 21 receives the activation signal to when the tag transmitting unit 22 transmits the response signal is:
(2Lc + Lp + L1 + Lm + L2) / V (second)
It becomes. For example, if L1 = 2m, L2 = 7m, Lm = 5m, Lc = 4m, Lp = 50m, V = 16.7m / second (= 60km / hour), the maximum response time of the tag is 4.31 seconds, and the tag transmitter 22 may transmit a response signal within the maximum response time after inputting the activation control signal. Note that when the position where the reader transmission unit (T) 11 transmits the activation signal falls within L1 according to the transmission cycle, the propagation time of the activation signal and the response signal is ignored.

  Thus, by installing the reader transmitting unit (T) 11 and the reader receiving unit (R) 12 in different vehicles 1A and 1B, the maximum response time is extended by the interval 2Lc + Lp. Further, a timer is connected to the tag transmission unit 22 so that a response signal is transmitted from the input time of the activation control signal to the maximum response time + α (α is a margin corresponding to fluctuations in the speed and interval of the vehicles 1A and 1B). By repeating the transmission, the reader receiving unit (R) 12 can surely receive the response signal, and the power consumption can be suppressed by stopping the transmission of the response signal thereafter.

  Since the reader transmission unit (T) 11 that transmits the activation signal and the reader reception unit (R) 12 that receives the response signal are installed in different vehicles 1A and 1B, the tag transmission unit 22 that transmits the response signal. If it is necessary to specify the maintenance monitoring object 5 or the sensor 23 in which is installed, these identifiers may be added to the response signal and transmitted. Thereby, the maintenance monitoring object 5 or the sensor 23 can be specified by the identifier of the response signal, and an unnecessary response signal can be deleted.

By the way, as shown in FIG. 8, the response signal transmitted by the tag transmission unit 22 also reaches the front of the tag transmission unit 22 in the traveling direction of the vehicle. Therefore, the mileage until the reader reception unit (R) 12 of the vehicle 1B can receive the response signal transmitted by the tag transmission unit 22 is
2Lc + Lp + L1 + Lm-L2
It becomes. That is, the vehicle 1B traveling behind Lp of the vehicle 1A is (2Lc + Lp + L1 + Lm−L2) to (2Lc + Lp + L1 + Lm + L2) after the vehicle 1A transmits the activation signal.
It is possible to receive a response signal transmitted by the tag transmitter 22 while traveling in the range.

The response signal transmission start time and response signal transmission end time (maximum response time of the tag) in the tag transmission unit 22 in accordance with the traveling of the vehicle 1B are as follows:
Response signal transmission start time: (2Lc + Lp + L1 + Lm−L2) / V
Response signal transmission end time: (2Lc + Lp + L1 + Lm + L2) / V
It becomes. In the above numerical example, the timing at which the reader reception unit (R) 12 of the vehicle 1B can receive the response signal transmitted by the tag transmission unit 22 is 3.47 seconds to 4.31 seconds after the tag reception unit 21 receives the activation signal. It becomes a range.

  However, the important point in the present invention is that the maximum response time of the tag is extended to 4.31 seconds, and the tag transmitter 22 sends the response signal before 3.47 seconds after the tag receiver 21 receives the activation signal. Even if it is transmitted, there is no particular problem as long as the reader receiver (R) 12 of the vehicle 1B cannot receive the response signal. In order to reduce power consumption, it is effective to connect a timer to the tag transmitter 22 and control the response signal transmission start time and the response signal transmission end time.

  For example, like the tag transmission unit 22 shown in FIG. 9, a response signal transmission timer 225 is connected to the transmission circuit / transmission antenna 221 and the data analysis storage circuit 222, and the response signal transmission start time and the response are determined according to the activation control signal. This can be handled by a configuration for controlling the signal transmission end time. Further, the control for stopping the transmission of the response signal at the maximum response time + α in the first to third embodiments can be handled by using the response signal transmission timer 225. Except for the response signal transmission timer 225 of the tag transmission unit 22, the configuration is the same as that of FIG.

  The first to fourth embodiments are based on the assumption that the speed V (m / s) of the vehicle 1 or the vehicles 1A and 1B is a specified value (for example, 16.7 m / second = 60 km / hour).

  The feature of the fifth embodiment is that, for example, in the vehicle 1 of the first to third embodiments or the vehicle 1A of the fourth embodiment, the traveling speed Vr of the vehicle is added to the activation signal and transmitted. In the tag of FIG. 9, the reception antenna / reception circuit 211 of the tag receiving unit 21 that has received the activation signal receives the activation signal, generates an activation control signal including the traveling speed Vr, and notifies the tag transmission unit 22 of the activation control signal. The response signal transmission timer 225 of the tag transmission unit 22 uses the travel speed Vr instead of the above-described maximum response time or the speed V of the formula for calculating the response signal transmission start time and the response signal transmission end time. The response signal can be accurately transmitted according to the timing at which the vehicle 1 or the vehicle 1B passes the reception area of the response signal.

  In the fourth embodiment, when the time difference between the vehicle 1A and the vehicle 1B is several hours or several days, the tag transmission unit 22 does not start the transmission of the response signal in response to the activation signal transmitted by the vehicle 1A. Controlling the transmission start time of the response signal in response to reception of the signal is extremely effective for reducing power consumption. For example, when it is known that the vehicle 1A passes the maintenance monitoring object 5 in the morning and the vehicle 1B passes the maintenance monitoring object 5 six hours after the vehicle 1A, the response signal of the tag transmission unit 22 The transmission timer 225 starts counting from the input time of the activation control signal, and the transmission circuit 221 starts transmission of the response signal after 6-β hours (β is a margin corresponding to fluctuations in the passing time of the vehicle 1B). And the data analysis storage circuit 222 is controlled.

  When the vehicle 1B passes through the maintenance monitoring object 5 three days after the vehicle 1A, the response signal transmission timer 225 starts counting from the input time of the activation control signal, and after 2 × 24−β hours ( β controls the transmission circuit 221 and the data analysis storage circuit 222 so as to start transmission of a response signal at a margin corresponding to the variation in the passing time of the vehicle 1B. Alternatively, a calendar function may be added to the timer 225, and the transmission circuit 221 and the data analysis storage circuit 222 may be controlled so as to start transmission of a response signal every predetermined maintenance inspection date.

  As described above, the feature of the sixth embodiment is that the tag transmitter 22 controls the transmission start time of the response signal when the interval between the vehicle 1A and the vehicle 1B is several hours or several days.

  In the present embodiment, the vehicle 1A and the vehicle 1B do not have to be separate vehicles, and can be sufficiently handled by the same vehicle. Even if the vehicle 1B travels in the opposite direction to the traveling direction of the vehicle 1A, the response signal transmission timer 225 is used to set the transmission start time of the response signal to the transmission circuit 221 and the data analysis storage circuit 222. It can respond by controlling. For example, one vehicle transmits an activation signal from the reader transmission unit (T) 11 on the forward path to start control of the transmission start time of the response signal in the tag, and the reader reception unit (R) 12 transmits a response signal on the return path. The present invention can also be applied to a receiving form.

  As described above, in the configuration of the sixth embodiment, the reader transmission unit (T) 11 and the reader reception unit (R) 12 are arranged separately in the front and rear of the vehicle, and the tag reception unit 21 and the tag transmission unit 22 are maintained. It is not always necessary to dispose the monitor object 5 separately. The tag receiving unit 21 and the tag transmitting unit 22 are linked, and the reader receiving unit (R) 12 and the reader transmitting unit (T) 11 are linked. Just do it. A configuration example of the wireless tag system of the sixth embodiment is shown in FIG.

  FIG. 10 (1) shows a state in which the reader transmission unit (T) 11 of the vehicle 1A transmits an activation signal, the tag reception unit 21 receives the activation signal, and the activation control signal is notified to the tag transmission unit 22. . The tag transmission unit 22 starts control of the transmission start time of the response signal so as to match the timing at which the vehicle 1B passes the maintenance monitoring object 5 with the start control signal as a trigger.

  In FIG. 10 (2), in accordance with the timing when the vehicle 1B passes the maintenance monitoring object 5, the tag transmitter 22 transmits a response signal, and the reader receiver (R) 12 of the vehicle 1B receives the response signal. In response to reception of the response signal, the reader transmitter (T) 11 transmits a stop signal, the tag receiver 21 receives the stop signal, and the stop control signal is notified to the tag transmitter 22. As shown in FIG. 10 (3), the tag transmission unit 22 is controlled to transmit a response signal from the response signal transmission start time to the response signal transmission end time. Transmission can be stopped.

FIG. 11 shows a configuration example of a wireless tag system according to the seventh embodiment of the present invention.
In FIG. 11, the feature of the seventh embodiment is that the vehicle 1 is provided with a reader transmission / reception unit (T / R) 13 and a beam tilt antenna 14, and an area having a high reception level is formed at the front and rear of the vehicle to reach the reach of radio waves. Is to extend

In the first embodiment, the reader transmission unit (T) 11 and the reader reception unit (R) 12 are installed separately at the front and rear of the vehicle 1 so that the maximum response time is extended by the interval Lc. . In this embodiment, the maximum reachable distance of the activation signal and the response signal transmitted / received from the reader transmitting / receiving unit (T / R) 13 via the beam tilt antenna 14 is L3 (m), and the interval between the tag receiving unit 21 and the tag transmitting unit 22 Let (the length of the manhole) be Lm (m) and the speed of the vehicle 1 be V (m / sec). At this time, the maximum response time allowed from when the tag receiving unit 21 receives the activation signal to when the tag transmitting unit 22 transmits the response signal is:
(2L3 + Lm + L2) / V (seconds)
It becomes. For example, if L3 = 10 m, Lc = 4 m, and V = 16.7 m / second (= 60 km / hour), the maximum response time of the tag is 1.44 seconds, and the tag transmission unit 22 receives this activation control signal and inputs this maximum A response signal may be transmitted within the response time. Note that when the position where the reader transmission unit (T) 11 transmits the activation signal falls within L3 according to the transmission cycle, the propagation time of the activation signal and the response signal is ignored.

  In the numerical examples of L1 = 2m and L2 = 7m in the first to fourth embodiments, the LF signal is used as the activation signal and the UHF signal is used as the response signal. L2 = 7 m and the maximum response time can be further extended. In the present embodiment, the UHF signal is used for both the activation signal and the response signal, and the beam tilt antenna 14 is used to extend L3 = 10 m. That is, L3> L1, L3> L2, and 2L3> Lc + L1 + L2.

  Here, the effect of the beam tilt antenna 14 will be described with reference to FIG. FIG. 12 shows the situation on the road where the vehicle 1 looking down from the sky travels. The same vehicle as the left vehicle 1 approaching the maintenance monitoring object (manhole) 5 at the center in the same arrangement as FIG. 1 shows a situation in which a maintenance monitoring object (manhole) 5 passes through the right side. A beam tilt antenna 14 is mounted on the roof of the vehicle 1, and a region where a UHF signal transmitted from the beam tilt antenna 14 can be received at a high level is drawn by a broken-line circle. In particular, on the road, the reception area having a high level of the UHF signal can be a front area A and a rear area B of the traveling vehicle 1. This indicates that one beam tilt antenna 14 can logically generate an effect similar to that in which transmission and reception are spatially separated before and after the vehicle 1 of the first to fourth embodiments. That is, the seventh embodiment and the first to fourth embodiments can be regarded as embodiments having the same effect due to the effect of creating a region with a high reception level before and after the vehicle 1.

  As described above, by using the beam tilt antenna 14, the maximum response time is extended by an amount corresponding to the increase in the maximum reach distance of the activation signal and the response signal. Further, by connecting a timer to the tag transmission unit 22 and repeatedly transmitting the response signal at a predetermined transmission period from the input time of the activation control signal to the maximum response time + α (α is an arbitrary margin), the reader reception unit ( R) 12 can surely receive the response signal, and power transmission can be suppressed by stopping transmission of the response signal thereafter.

  Also in the present embodiment, as in the fifth embodiment, the travel speed Vr of the vehicle 1 is notified to the tag, and the travel speed Vr is used in place of the speed V in the equation for calculating the maximum response time. The response signal can be accurately transmitted according to the timing at which 1 passes through the response signal reception area.

1,1A, 1B Vehicle 5,5A, 5B Maintenance monitoring object (manhole)
11 Reader transmitter (T)
111 Control Circuit 112 Transmitter Circuit / Transmitter Antenna 12 Reader Receiver (R)
121, 122 Receiving antenna / receiving circuit 123 Combining / demodulating circuit 124 Data storage circuit 13 Reader transmission / reception unit (T / R)
14 beam tilt antenna 21 tag receiving unit 211 receiving antenna / receiving circuit 22 tag transmitting unit 221 transmitting circuit / transmitting antenna 222 data analysis storage circuit 223 measurement data collection circuit 224 measurement data collection / analysis timer 225 response signal transmission timer 23 sensor

Claims (9)

A tag installed on a maintenance monitoring object and a reader installed on a moving body that passes in the vicinity of the maintenance monitoring object. The activation signal is transmitted from the reader at a predetermined cycle, and the activation signal is In the wireless tag system that transmits a response signal from the received tag and receives the response signal by the reader,
The reader has a configuration in which a reader transmission unit that transmits the activation signal is installed in front of the moving body, and a reader receiver that receives the response signal is installed in the rear of the moving body,
The tag has a tag receiving unit that receives the activation signal before the moving direction of the moving body, and a tag transmitting unit that transmits the response signal ahead of the moving direction of the moving body. The response signal is transmitted from the tag receiver in response to the activation signal reception notification.
Further, the tag analyzes measurement data obtained by measuring the state of the maintenance monitoring object, stores the analysis data, reads the analysis data in response to the reception notification of the activation signal, and transmits it as the response signal A wireless tag system comprising a control means for performing the operation. The wireless tag system according to claim 1,
There are at least two maintenance monitoring objects on the moving path of the moving body, the tag receiving unit is installed on the first maintenance monitoring object before the moving direction of the moving body, The tag transmission unit is installed in a second maintenance monitoring object, and the activation signal is notified from the tag reception unit to the tag transmission unit via a cable.
The tag control means is configured to transmit the analysis data corresponding to the state of at least one of the first maintenance monitoring object and the second maintenance monitoring object as the response signal. Wireless tag system. The wireless tag system according to claim 1,
A configuration in which the tag receiving unit of the tag is installed in front of the moving body away from the maintenance monitoring object, and the activation signal is notified from the tag receiving unit to the tag transmitting unit via a cable. A wireless tag system characterized by being. The wireless tag system according to claim 1,
The moving body is composed of at least two units that move at a predetermined interval. The reader transmitting unit is installed in the first moving body at the front, and the reader receiving unit is installed in the second moving body at the rear. A wireless tag system characterized by the above. The wireless tag system according to claim 1,
The tag transmission unit determines a timing when the tag transmission unit and the reader reception unit can communicate with each other after receiving the activation signal reception notification, and starts transmission of the response signal at the timing A wireless tag system comprising a timing control means. The wireless tag system according to claim 1,
The moving body is composed of at least two units that move at a predetermined interval. The reader transmitting unit is installed in the first moving body at the front, and the reader receiving unit is installed in the second moving body at the rear. Is a configuration to
The tag transmission unit has a positional relationship in which the tag transmission unit and the reader reception unit can communicate after receiving the reception notification of the activation signal due to a time difference between the first mobile unit and the second mobile unit. A wireless tag system comprising: a transmission timing control unit that determines timing and starts transmission of the response signal at the timing. The wireless tag system according to claim 4 or 6,
The wireless tag system according to claim 1, wherein the first moving body and the second moving body are realized by a single moving body that moves at a predetermined time difference. The wireless tag system according to claim 1,
The reader receiving unit is configured to include two receiving means for receiving the response signal and means for diversity combining the received signals. The wireless tag system according to claim 1,
The tag transmission unit is configured to repeatedly transmit the response signal at a predetermined transmission cycle.

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