JP2008005432A - Wireless tag detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless tag detection system in which a radio wave used when a reader reads information from a wireless tag, and a radio wave used when the reader transmits information to a receiver, are prevented from interfering with each other without using a new frequency band. <P>SOLUTION: In the wireless tag detection system 1, a reader 101 generates a reading command including tag data corresponding to tag responses sent back from wireless tags 102, 103 and transmits the reading command. The reading command transmitted from the reader 101 is used not only for outputting tag responses from the wireless tags 102, 103 but also for acquiring tag data in a command receiver 104. The radio wave used when the reader 101 reads information from the wireless tags 102, 103, and the radio wave used when the reader 101 transmits information to the receiver, are therefore prevented from interfering with each other without using the new frequency band. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a system using a wireless tag and a reader, and detecting the presence of the reader by reading information held by the wireless tag. In particular, the present invention relates to a technology that contributes to traffic safety by notifying the presence of a pedestrian or another vehicle by providing a wireless tag to a pedestrian or mounting it on a vehicle and detecting it.

  In recent years, in the system as described above, a system has been devised in which a pedestrian is provided with a wireless tag or a wireless tag is mounted on a vehicle to notify another vehicle of the presence of the pedestrian or the vehicle ( For example, see Patent Document 1).

  In this system, the pedestrian is given a wireless tag, the presence of the pedestrian is detected by reading the wireless tag with a reader placed beside the road, and the detection result is sent to the vehicle using another communication device. Notification is made to the on-board communication device installed.

Furthermore, a system is also known in which a wireless tag is mounted on a vehicle, and a pedestrian is provided with a reading device so that the reading device detects the approach of the vehicle and notifies the pedestrian (see, for example, Patent Document 2). .
JP 2003-346297 A JP 2003-173499 A

However, when a pedestrian or a vehicle is detected using a wireless tag and its presence is notified to another vehicle, there is a problem with the notification method.
For example, in Patent Document 1, an in-vehicle communication device is used for notification. For this purpose, in addition to the RFID tag reader, a transmitter for notifying the in-vehicle communication device of the detection result is additionally required in addition to the equipment installed on the roadside, which increases the cost of the roadside equipment. There is.

  On the other hand, in the technique of Patent Document 2, since the wireless tag mounted on the vehicle and the reading device carried by the pedestrian directly communicate with each other, the system is simplified as compared with Patent Document 1, but the reading device is used by the pedestrian. It is necessary to carry a relatively complicated electronic device, and there are many problems in widespread use in terms of cost and power supply (that is, battery life).

Furthermore, both of the above techniques have concerns about problems when many pedestrians and vehicles use the system.
Specifically, in the technique of Patent Document 1, it is necessary to mount an in-vehicle communication device in a vehicle in order to receive a notification of a detection result. In addition, when the number of in-vehicle communication devices that want to receive notification of detection results increases, there is a possibility that interference such as so-called congestion occurs, in which individual communication is concentrated and information is difficult to be transmitted quickly.

  In addition, in this technology, it is necessary to secure two types of frequency bands, that is, frequency channels, that is, a radio wave for a wireless tag and a radio wave for an in-vehicle communication device, and there is a problem in terms of effective utilization of radio wave resources.

  Furthermore, in Patent Document 2, when many pedestrians with readers concentrate in a nearby place, there is a concern that the read signals transmitted by the readers may interfere with each other, making it difficult to read the wireless tag efficiently. .

  Therefore, in view of such a problem, in a wireless tag detection system in which a reading device receives information from a wireless tag and wirelessly transmits the received information to a receiver mounted on, for example, a vehicle, a new frequency Without using a band, radio waves when the reading device reads information from the wireless tag and radio waves when the reading device transmits information to the receiver are prevented from interfering with each other, and an inexpensive system It is an object of the present invention to provide

  The wireless tag detection system according to claim 1, wherein the reader generates a transmission signal including tag data corresponding to a response signal sent back from the wireless tag, and is configured to achieve the object. Send. The transmission signal transmitted from the reading device is used not only when the response signal is output by the wireless tag but also used by the receiving device to acquire tag data.

  Therefore, according to such a wireless tag detection system, the radio wave when the reading device reads information from the wireless tag and the information when the reading device transmits information to the receiver without using a new frequency band. The radio waves can be prevented from interfering with each other.

In addition, since it is not necessary to provide communication means for the receiver in the reading apparatus, a system can be constructed at a low cost.
The “recognition data” in the present invention indicates data such as the type of wireless tag and the individual number (identifier: ID) of the wireless tag. The “response signal” only needs to include at least recognition data. When the wireless tag has a function of detecting various information such as a moving speed and a moving direction, the wireless tag The various information may be transmitted as a response signal together with the recognition data.

  In addition, the “tag data” in the present invention is information on presence / absence of a wireless tag, the above-described recognition data, information on the number of wireless tags, information indicating that response signals transmitted from a plurality of wireless tags collide, etc. The data is shown.

  By the way, in the wireless tag detection system according to claim 1, the signal generation means of the reader extracts recognition data from the response signal received through the reception means as described in claim 2, and at least the recognition data is detected. A transmission signal including data as tag data may be generated.

  According to such a wireless tag detection system, the receiving device can receive wireless tag recognition data received by the reader. Therefore, the receiving apparatus can recognize detailed information (information included in the recognition data) of the wireless tag.

  Further, in the wireless tag detection system according to claim 1 or 2, the signal generation means of the reader detects whether or not a response signal has been received via the reception means as described in claim 3. Thus, the presence / absence of a wireless tag that has sent back a response signal may be detected, and a transmission signal including the detection result as the tag data may be generated.

  According to such a wireless tag detection system, even if response signals from a plurality of wireless tags collide and the content of each response signal cannot be identified by the reader, the receiving device can be sure only if there is a wireless tag. Can be detected.

  The wireless tag detection system according to any one of claims 1 to 3, wherein at least the wireless tag is present on the reception device based on the tag data extracted by the extraction unit as described in claim 4. Informing means for informing the user of the receiving apparatus of whether or not the information is present may be provided.

  According to such a wireless tag detection system, the presence or absence of a wireless tag can be notified to the user. Further, for example, even when the receiving device performs control of the device on which the receiving device is mounted (control for suppressing the moving speed of the receiving device, etc.) based on the received tag data, Since at least the presence / absence of the wireless tag is notified to the user, the user can recognize that the control of the device is performed by the receiving device.

  Furthermore, in the wireless tag detection system according to claim 4, as described in claim 5, the reader has successfully extracted the detection result of the presence or absence of the wireless tag that has returned the response signal and the recognition data. It is configured to generate a transmission signal in which the detection result of whether or not is included as tag data, and the receiving device extracts an extraction result indicating that there is a wireless tag that has sent back a response signal and that the recognition data has not been successfully extracted. If it is obtained by the means, the first detection information indicating that there are a plurality of wireless tags that have sent back response signals is notified to the user of the receiving device, and there are wireless tags that have sent back response signals, and the recognition data is normally extracted. If an extraction result indicating that it has been obtained is obtained, the second detection information indicating the contents of the tag data including the recognition data may be notified to the user of the receiving device.

  According to such a wireless tag detection system, the user of the receiving device indicates that a plurality of wireless tags are detected (first detection information) and that one wireless tag is detected (second detection information). Can be identified.

  Further, in the wireless tag detection system according to claim 4 or claim 5, as described in claim 6, the wireless tag is carried as at least a pedestrian as recognition data, or is a bicycle, a motorcycle, The mounting information indicating which vehicle of the automobile is mounted (the type of vehicle on which the wireless tag is mounted) is transmitted, and the reading device receives a transmission signal including the mounting information received from the wireless tag as the tag data. The generation device may be configured to notify the user of the reception device of the presence or absence of a pedestrian, bicycle, motorcycle, or automobile based on the mounting information included in the transmission signal received from the reading device.

According to such a wireless tag detection system, it is possible to notify the user of the receiving device whether the reading device has detected a pedestrian, bicycle, motorcycle, or automobile.
Furthermore, in the wireless tag detection system according to any one of claims 1 to 6, the reading device changes the receivable region of the transmission signal transmitted by the transmission unit as described in claim 7. The signal generation means may generate a transmission signal including area information representing a transmission range of the transmission signal by the range changing means in the tag data.

  According to such a wireless tag detection system, the receiving device can detect in which receivable region the wireless tag exists by extracting area information from the tag data of the transmission signal.

  Further, in the wireless tag detection system according to claim 7, the area changing unit changes the receivable area by causing the transmission unit to change the transmission output of the transmission signal, as described in claim 8. Alternatively, as described in claim 9, the receivable area may be changed by causing the transmission means to change the transmission angle of the transmission signal.

According to such a wireless tag detection system, the configuration as the area changing unit can be more specifically realized.
Furthermore, in the wireless tag detection system according to any one of claims 7 to 9, the area changing unit may sequentially increase the receivable area as described in claim 10.

  According to such a wireless tag detection system, a wireless tag existing near the reader can be detected at an early stage. For this reason, for example, if the reader is placed in a place where an accident such as an intersection is likely to occur, and the wireless tag is moved together with the pedestrian or the vehicle, the receiving device will read the information of the wireless tag in the order closer to the intersection. Therefore, it is possible to make an accident less likely to occur even in a place where an accident is likely to occur.

  In the wireless tag detection system according to claim 10, as described in claim 11, the signal generation means of the reader transmits the transmission signal by the transmission means while the receivable area is changed by the area change means. In addition, a transmission signal may be generated that includes, as tag data, a sequence number representing the number of executions of a series of transmission procedures until the transmission signal is transmitted again by the transmission means in the first receivable area. In this case, when the response means of the wireless tag receives the transmission signal, it analyzes the tag data, and if it detects that the sequence number included in the tag data has been changed from the previous sequence number, it is included in the tag data. The area information is stored in the storage means, a response signal is sent back, the sequence number is not changed from the previous sequence number, and the area information included in the tag data is changed from the area information stored in the storage means. If it is detected, the response signal may not be sent back.

  That is, if the reading device sequentially expands the receivable area and transmits a transmission signal, the number of wireless tags that respond to the transmission signal increases as the receivable area is expanded, so the probability that the response signal collides increases. . However, according to the configuration of the present invention, the wireless tag that responds to the transmission signal does not respond when the area information is changed (enlarged) in the same sequence number, so even when sequentially expanding the receivable area, It is possible to reduce collision of response signals with respect to transmission signals.

  Therefore, according to such a wireless tag detection system, the possibility of collision of responses of a plurality of wireless tags is reduced, and the detection time can be shortened, so that the reception accuracy of the response signal from the wireless tag is improved. Can do.

  Furthermore, in the wireless tag detection system according to claim 11, the wireless tag response means, as described in claim 12, is the state in which the sequence number has not been changed from the previous sequence number, and is added to the tag data. When it is detected that the included area information has not been changed from the area information stored in the storage means, it may be set whether or not to send back a response signal with a preset probability depending on the type of the wireless tag. .

  According to such a wireless tag detection system, it is possible to set a priority order for sending back a response signal according to the type of the wireless tag. For this reason, for example, if a high priority is set for a wireless tag mounted on an object that moves at a high speed, such as a bicycle or a motorcycle that has a high probability of an accident compared to a pedestrian (the probability that a response signal is sent back is set high). It is possible to preferentially detect an accident with a high probability.

  Note that the process of determining whether or not the wireless tag sends back a response signal can be performed in various ways, for example, by generating a random number in the wireless tag and determining whether or not the value of the random number exceeds a preset threshold value. Processing can be considered.

  In addition, in the wireless tag detection system according to claim 12, the wireless tag is moved at a speed equal to or higher than a preset threshold speed as described in claim 13, or the wireless tag That the wireless tag is moving at a speed equal to or higher than the threshold speed by the movement detection means, or that the wireless tag is approaching the reading apparatus. Probability changing means for changing the probability of sending back the response signal to a higher probability when it is detected may be provided.

  That is, in the present invention, the priority order for sending back a response signal is set high so that the wireless tag moving at a speed equal to or higher than the threshold speed and the wireless tag approaching the reader are dangerous.

  Therefore, according to such a wireless tag detection system, it is possible to preferentially detect a wireless tag moving at a speed equal to or higher than the threshold speed and a wireless tag approaching the reading device. It is possible to prevent the owner or a moving object equipped with a wireless tag and a moving object equipped with a receiving device from coming into contact with each other in the vicinity of the reading device. Therefore, if the reading device is arranged at a place where an accident is likely to occur, such as an intersection, the accident can be made difficult to occur.

  Further, in the wireless tag detection system according to any one of claims 7 to 13, the signal generation means of the reading device transmits the position information indicating the installation position of the reading device as the transmission signal as described in claim 14. You may make it produce | generate by including.

  According to such a wireless tag detection system, the signal generation unit of the reader generates the transmission signal by including the position information indicating the installation position of the reader and the area information indicating the transmission range of the transmission signal. Therefore, the receiving apparatus can specify the area where the wireless tag exists.

  Furthermore, in the wireless tag detection system according to claim 14, as described in claim 15, the reception device includes a current location detection unit that detects a current location of the reception device, a current location detected by the current location detection unit, and a reading There may be provided a positional relationship detecting means for detecting the positional relationship between the receiving device and the wireless tag based on the positional information received from the device.

  According to such a wireless tag detection system, since the current location of the receiving device can be detected in addition to the current location of the wireless tag (region where the wireless tag exists), the positional relationship between the receiving device and the wireless tag is detected. be able to.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic explanatory diagram of the wireless tag detection system 1 of the first embodiment. In this wireless tag detection system 1, a pedestrian or a bicycle is detected at a location on a road where an accident such as an intersection is likely to occur, and a vehicle such as a running passenger car (a command receiver 104 (104a mounted on the vehicle). ~ 104c)) is notified of its existence, which is useful for preventing traffic accidents.

  As shown in FIG. 1, the wireless tag detection system 1 has a reader 101 (reading device) installed near an intersection (for example, a utility pole with a traffic light or a signboard near the intersection), and a wireless tag 102 is provided to a pedestrian. (102a, 102b) is attached, and the wireless tag 103 (103a, 103b) is attached to the bicycle, and the wireless tag 102, 103 is detected by the reader 101.

  The vehicle 104 is equipped with a command receiver 104 (reception device), receives radio waves from the reader 101, analyzes the contents of a read command (transmission signal) issued by the reader 101, and detects the presence of the wireless tags 102 and 103. Detects and alerts the driver. A command analysis example and warning content will be described later.

  Next, each component which comprises the wireless tag detection system 1 is demonstrated using FIG. FIG. 3 is a block diagram illustrating a schematic configuration of the reader 101, the wireless tags 102 and 103, and the command receiver 104.

  The reader 101 modulates the read command generated by the control circuit 10 using the modulator 11, amplifies it using the power amplifier 12, and transmits it from the transmission / reception antenna 14 via the circulator 13. The reader 101 receives tag responses (response signals) from the wireless tags 102 and 103 by the transmission / reception antenna 14, amplifies them by the reception amplifier 15, demodulates them by the demodulator 16, and transmits them to the control circuit 10.

The circulator 13 prevents the read command output from the power amplifier 12 from entering the reception amplifier 15 side.
In addition, the reader 101 acquires a tag response from the wireless tags 102 and 103 by using a technique similar to that used in a known technique (for example, the technique described in ISO standard 18000-6). The radio tag is configured to detect a radio tag several meters to 10 meters ahead by using, for example, the UHF band as a radio wave used for transmission and reception.

  Next, transfer characteristics of radio waves transmitted / received from the transmission / reception antenna 14 of the reader 101 will be described with reference to FIG. FIG. 2A shows an example of a beam pattern from the transmission / reception antenna 14. FIG. 2B shows an example of attenuation when the radio wave transmitted from the antenna propagates through space.

  As shown in FIG. 2A, the transmission / reception antenna 14 is configured as a general directional antenna that transmits and receives radio waves in the front (0 deg) direction. Note that although the radio waves from the transmission / reception antenna 14 are weaker than the front, some radio waves are actually output to the side (± 90 deg) and the rear (180 deg). Therefore, radio waves can be transmitted and received even in directions other than the front.

  The transmission / reception antenna 14 has a gain of 2.15 dBi, for example. The transmission / reception antenna 14 is arranged at a position of 1.5 m above the ground, and 1 W of transmission power is transmitted at a position (reference point) of 0 m. When a radio wave having a frequency of 950 MHz is transmitted using a device, a received power characteristic as shown in FIG. 2B is obtained (theoretical calculation value).

  Here, for example, the operation reception power of a generally used wireless tag is about −20 dBm. Therefore, when a wireless tag that requires power of −20 dBm is used, it can be seen from the graph shown in FIG. 2B that the maximum distance that the wireless tag can detect is 15 m.

  On the other hand, the command receiver 104 used in the present embodiment includes the reception amplifier 53 and does not need to return a tag response to the reader 101. Therefore, the command receiver 104 can be operated with a small reception power. For example, it is very easy for the command receiver 104 to detect a power of −40 dBm even using a currently widely known technique.

  Therefore, the range in which the command receiver 104 can receive and analyze the read command from the reader 101 (command receiver detection area (see, for example, FIG. 9)) is much wider than the range in which the wireless tags 102 and 103 can respond. (In the example shown in FIG. 8B, it is within a range of 100 m or more).

In the present embodiment, in consideration of such characteristics, the command receiver 104 receives a read command from the reader 101.
Next, as the wireless tags 102 and 103, for example, a passive type wireless tag 102 or a semi-passive type wireless tag 103 is employed.

  In the passive type wireless tag 102, a part of the radio wave from the reader 101 received by the transmission / reception antenna 21 is guided to the rectifier circuit 24, converted into electric power, and used as the operating power of the wireless tag 102 itself. The remaining radio waves are guided to the reflection type modulator 22, and subjected to modulation based on recognition data (specific information such as ID and serial number) for specifying the wireless tag according to an instruction from the control circuit 23. Is sent back to the reader 101.

  The semi-passive type wireless tag 103 has the same basic operation principle as that of the passive type 102, but includes a power source 34, and supplies power to the reflective modulator 32, the control circuit 33, and the GPS receiver 37. Therefore, all the radio waves from the reader 101 can be used for the response of the wireless tag 103.

  In addition, as shown in FIG. 3, in the semi-passive type wireless tag 103, the speed sensor 35 and the direction sensor 36 are connected to the control circuit 33, so that the control circuit 33 uses the wireless tag 103 in addition to the recognition data. The speed of the mounted object (that is, the speed and traveling direction of the bicycle in the example of FIG. 1) can be returned to the reader 101 by placing it on the response of the wireless tag.

  Here, since the passive type wireless tag 102 does not require a power source, the wireless tag 102 can be manufactured without worrying about running out of the battery, small size, light weight, and low cost. Therefore, as described with reference to FIG. 1, it is particularly suitable for an application carried by a pedestrian.

  In addition, the semi-passive type wireless tag 103 separately supplies a power source 34 for the modulator and the control circuit 33. However, since the necessary power is very small, when mounting the wireless tag 103 on a bicycle, for example, A dynamo generator can be used for the power source 34.

  The control circuits 23 and 33 constituting the wireless tags 102 and 103 have a function of analyzing the contents of the received read command and determining whether or not to transmit a tag response according to the analysis result.

  The command receiver 104 does not have a radio wave transmission function, but has only a function of receiving a read command issued by the reader 101. Specifically, the read command received by the reception antenna 54 is amplified by the reception amplifier 53, demodulated by the demodulator 52, and then the content of the read command is analyzed by the command analysis unit 51. As a result of the analysis, when it is determined that the reader detects that a wireless tag is present in the vicinity, for example, the detection result is displayed on the detection result display unit 55 configured as a liquid crystal color display. A warning sound is output from the warning output unit 56 configured as follows to alert the driver of the vehicle on which the command receiver 104 is mounted. Thus, the driver knows that there are pedestrians and bicycles with wireless tags 102 and 103 at nearby intersections, and this vehicle comes into contact with pedestrians and bicycles with wireless tags 102 and 103. Accidents can be avoided.

Next, processing executed by the reader 101, the wireless tags 102 and 103, and the command receiver 104 in the wireless tag detection system 1 will be described in order.
First, FIG. 4 is a flowchart showing a reader process executed by the control circuit 10 of the reader 101. The reader process is a process that is repeatedly executed when the power of the reader 101 is turned on. First, the counter C is set to 0 (S110). Then, a GROUP_SELECT command (simultaneous call signal) is transmitted (S115).

  Subsequently, it is determined whether or not a tag response from the wireless tags 102 and 103 is received within a predetermined time set in advance and whether or not there is a collision in the tag response (S120). If no tag response has been received from the wireless tags 102 and 103 (S120: No), a SUCCESS command is transmitted (S125), and the counter C is incremented (S160).

  If the tag response is received from the wireless tags 102 and 103 and there is no collision (S120: Yes, no collision), the IDs of the wireless tags 102 and 103 included in the received tag response are extracted. A DATA_READ command for requesting a response from the wireless tags 102 and 103 is transmitted by designating the ID 103 (S130).

  Then, a tag response (data) is received from the designated wireless tags 102 and 103 (S135), and it is determined whether the tag response has been received normally (S140). If the tag response can be normally received (S140: Yes), a SUCCESS command is transmitted (S145), and the counter C is incremented (S160).

  If the tag response cannot be received normally (S140: No), a RESEND command is transmitted (S150), and the counter C is incremented (S160). The RESEND command is the same as the DATA_READ command, and the wireless tags 102 and 103 that have received the RESEND command operate in the same manner as when the DATA_READ command is received. However, the operation of the wireless tags 102 and 103 will be described later.

  Next, in S120, a tag response is received from the wireless tags 102 and 103. If there is a collision (S120: Yes, there is a collision), a FAIL command is transmitted (S155), and the counter C is incremented (S160).

  Subsequently, it is determined whether or not the value of the counter C has exceeded a preset specified number of times Cmax (Cmax is a value of about 10 to several tens, for example) (S165). If the value of the counter C exceeds the specified number of times Cmax (S165: Yes), the process returns to S120.

  If the value of the counter C does not exceed the specified number of times Cmax (S165: No), an INITIALIZE command is transmitted (S170), and the reader process is repeated from the beginning. Note that after transmitting each command in the reader process, the reader 101 continuously transmits unmodulated radio waves. This radio wave serves as an energy source for the passive type wireless tag 102 and is also used as a radio wave that modulates the tag response by the reflection modulator 22.

Next, FIG. 5 is a flowchart showing wireless tag processing executed by the control circuit 23 (33) of the wireless tag 102 (103).
This wireless tag process is started when various commands (read commands) transmitted in the above-described reader process are received. First, the type of the command transmitted from the reader 101 is analyzed (S210). ). Then, the following processing is executed according to the analysis result.

  That is, if a GROUP_SELECT command is received, the counter C is set to 0 (S215), a tag response including at least an ID is transmitted (S220), and the wireless tag processing is terminated.

  If the FAIL command is received, it is determined whether or not the counter C is 0 (S225). If the counter C is 0, a random number is generated, and 0 or 1 is held as a result value p according to the value of the random number (S230). As a process for generating random numbers in this way, for example, a random number table in which numerical values are arranged in random order is prepared in advance, and whether the numerical value selected using the random number table exceeds a preset random number threshold value. It may be configured to output 0 or 1 as the result value p based on whether or not.

  Subsequently, it is determined whether or not the result value p held according to the random number value is 1 (S235). If the result value p is 1 (S235: Yes), the counter C is incremented (S240), and the wireless tag process is terminated.

If the result value p is 0 (S235: No), a tag response including at least an ID is transmitted (S245) in the same manner as the process of S220, and the wireless tag process is terminated.
Next, if the SUCCESS command is received in S210, the counter C is decremented (S250), and it is determined whether the counter C is 0 or less (S255). If the counter C is 0 or less (S255: Yes), a tag response including at least an ID is transmitted (S260) as in the process of S220, and the wireless tag process is terminated.

If the counter C is greater than 0 (S255: No), the wireless tag process is terminated as it is.
Next, if the DATA_READ command (RESEND command) is received in S210, it is determined whether or not the ID possessed by itself is included in the DATA_READ command (S265). If the ID that the user owns is included in the DATA_READ command (S265: Yes), the ID and detailed information (for example, information by the speed sensor 35 and the direction sensor 36, etc.) are transmitted (S270), and the RFID tag processing is performed. finish.

If the ID owned by the user is not included in the DATA_READ command (S265: No), the wireless tag process is terminated.
If the INITIALISE command is received in S210, the stored data is initialized (counter C is cleared here), and the wireless tag processing is terminated.

Next, FIG. 6 is a flowchart showing a receiver process executed by the command analysis unit 51 of the command receiver 104.
The receiver process is a process started when the command receiver 104 is turned on. First, the counter C and the detection flag F indicating the detection state of the SUCCESS command are cleared. That is, the counter C is set to 0, and the detection flag F indicating the detection state of the SUCCESS command is set to 0 (S310).

  Subsequently, a process of receiving and analyzing a read command from the reader 101 is performed (S315), and it is determined whether or not the read command is received from the reader 101 within a preset specified time (S320). Then, it is determined whether or not a command other than the GROUP_SELECT command or the SUCCESS command has been received (S325). If a read command is received from the reader 101 within the specified time (S320: Yes) and a command other than a GROUP_SELECT command or a SUCCESS command is received (S325: Yes), the counter C is cleared (S330).

  Then, it is determined whether or not the detection flag F is 0 (that is, detection of a command other than the GROUP_SELECT command or the SUCCESS command is the first time) (S335). If the detection flag F is other than 0 (that is, 1) (S335: No), it is determined whether or not the received command (read command) is a FAIL command (S340).

  If the received command is a FAIL command (S340: Yes), the process returns to S315. If the received command is not a FAIL command (S340: No), the detected content is added to a memory such as a RAM based on the received command (for example, an ID included in the DATA_READ command) (S345), and the process of S315 is performed. Return.

  If the detection flag F is 0 in S335 (S335: Yes), it is determined whether or not the received command (read command) is a FAIL command (S350). If the received command is a FAIL command (S350: Yes), for example, warning information for alerting the driver such as “careful about popping out” is output (S360), and the detection flag F is set to 1. , The process returns to S315.

  If the received command is not a FAIL command (S350: No), an alarm such as “There is a pedestrian” is output based on the received command (for example, an ID included in the DATA_READ command) (S355), and a detection flag F is set to 1 (S365), and the process returns to S315. Note that the warnings and alarms output in S360 and S355 are performed by outputting a voice using the warning output unit 56 and displaying a message indicating the warning or warning on the detection result display unit 55.

  Further, when the read command from the reader 101 is not received within the designated time (S320: No), or even when the read command is received from the reader 101 within the designated time, the SUCCESS command is received. If this is the case (S325: No), the counter C is incremented (S370), and the value of the counter C (number of reception trials) is a predetermined number of times Cmax (Cmax is a value of about 10 to several tens, for example) (It may be a value different from Cmax in the container processing.) It is determined whether or not the value has exceeded (S375).

  If the value of the counter C exceeds the specified number of times Cmax (S375: Yes), the counter C and the detection flag F are cleared (S380), and the process returns to S315. If the value of the counter C does not exceed the specified number of times Cmax (S375: No), the process returns to S315.

  Next, an example of a signal exchanged in each of the above processes and an example of a process for the command receiver 104 receiving the read command from the reader 101 to analyze the command and know the presence of a pedestrian or a bicycle Show. FIG. 7 is a ladder chart showing signal exchange executed in the reader process, the wireless tag process, and the receiver process.

  In this example, the exchange of signals in the reader 101, the wireless tags 102a, 102b, and 103a and the command receivers 104a and 104b is described according to the temporal transition. As shown in FIG. 7, the wireless tags 102a, 102b, and 103a have a READY state, an ID state, and a DATA_EX state. The READY state indicates a state in which each command can be received, and an ID state. Indicates a state in which all of the wireless tags 102a, 102b, and 103a respond, and the DATA_EX state indicates a state in which only the specific wireless tags 102a, 102b, and 103a to which IDs are specified respond.

  In the ladder chart shown in FIG. 7, first, the reader 101 sends a GROUP_SELECT command (S115) to inform the wireless tags 102a, 102b, 103a to prepare to return an ID. As a result, the wireless tags 102 a, 102 b, and 103 a that are within the range where the radio wave from the reader 101 reaches return tag responses including their own IDs to the reader 101.

  Here, as shown in FIG. 7, when a plurality of wireless tags return responses simultaneously, interference of tag responses from each wireless tag (so-called tag response collision) occurs, and the reader 101 determines the ID. It cannot be read correctly (S120).

  The reader 101 which has detected such a tag response collision transmits a FAIL command (S155). The wireless tag that has received this FAIL command starts a plurality of reading processes known in the prior art. That is, the multiple reading process is a process of adjusting an opportunity to reply using a random number or the like so that the responses of the wireless tags do not overlap each other. Such multiple reading processing is disclosed in, for example, “Klaus Finkenzeller's RFID Handbook, published February 26, 2001, Nikkan Kogyo Shimbun P.145-147”.

  Incidentally, the FAIL command generated by the reader 101 reaches the command receiver 104 as well. Therefore, the command receiver 104 can know that the reader 101 has issued a FIAL command. Since this means that there are a plurality of wireless tags 102 and 103 around the reader 101, the command receiver 104 may issue a warning message that “a plurality of pedestrians or bicycles exist”. Yes (S360).

  Thereafter, the reader 101 sequentially reads the IDs of the wireless tags 102a, 102b, and 103a existing in the vicinity based on a plurality of reading processes. For example, when the wireless tag of 102b gets a response opportunity and returns its own ID (S245), the reader 101 recognizes the ID and transmits a DATA_READ command to the wireless tag of 102b (S130).

  This command specifies the ID of 102b itself. Thereby, although the DATA_READ command reaches all the wireless tags, since the ID of 102b is described as the designation destination, only the data 102b can return detailed data and transmit it to the reader 101.

  Here, when the command receiver 104 receives the DATA_READ command and analyzes the ID of the designated destination, the command receiver 104 can know that this command is directed to the wireless tag 102b held by the pedestrian ( However, it is assumed that 102a and 102b are wireless tags possessed by pedestrians when an ID number is assigned in advance. Therefore, the command receiver 104 is more specific than “there is a pedestrian”. Information can be transmitted (S345).

  Thereafter, the reader 101 sequentially reads information on the wireless tags 102a and 103a. At this time, since the DATA_READ command is transmitted by designating IDs of 102a and 103a, the command receiver that has received the command can sequentially know the existence of these pedestrians and bicycles.

  In the above example, since the conventional read command has been described as an example, the wireless tags 102a, 102b, and 103a only return an ID. However, for example, as in the wireless tag 103 described in FIG. In the case of the wireless tag provided, the wireless tag 103 returns speed information in addition to the ID, and when the reader transmits DATA_READ to the wireless tag 103, a read command is used to include the speed information in addition to the ID. If specified, the command receiver can be informed of the ID and speed, that is, information “30 km / h by bicycle”. Thereby, when issuing a warning to the driver, a more specific and effective warning can be issued.

In the present embodiment, the reader process (FIG. 4) corresponds to a signal generation unit and a transmission unit in the present invention.
Further, the wireless tag processing (FIG. 5) corresponds to the response means referred to in the present invention.

Further, the receiver processing (FIG. 6) corresponds to the extraction means and notification means (S355, S360) in the present invention.
In the wireless tag detection system 1 described in detail above, the reader 101 generates a read command including tag data corresponding to the tag response sent back from the wireless tags 102 and 103, and transmits this read command. The read command transmitted from the reader 101 is not only used when outputting a tag response by the wireless tags 102 and 103 but also used by the command receiver 104 to acquire tag data.

  Therefore, according to the wireless tag detection system 1 as described above, the radio wave when the reader 101 reads information from the wireless tags 102 and 103 without using a new frequency band and the reader 101 to the receiver. Thus, radio waves when transmitting information can be prevented from interfering with each other.

  In addition, according to such a wireless tag detection system 1, only the cost of the reader 101 is required to notify the detection results of the wireless tags 102 and 103 to the vehicle, and a new wireless device such as an in-vehicle communication device is required. Therefore, the system can be constructed at a low cost. In addition, since the detection of the wireless tags 102 and 103 only receives the transmission command of the reader 101, the problem of congestion does not occur even when there are many vehicles equipped with the command receiver 104.

  In addition, as described above, the wireless tags 102 and 103 according to the present embodiment detect a collision of the plurality of wireless tags 102 and 103 and then read the contents of the individual wireless tags 102 and 103. Is adopted. That is, the command transmitted by the reader 101 includes information that the collision of the wireless tags 102 and 103 has been detected, and the command receiver 104 receives the command transmitted by the reader 101, analyzes it, and analyzes the collision. Detect the presence or absence.

Therefore, the command receiver 104 can know whether or not the wireless tags 102 and 103 exist in the area where the read command from the reader 101 can be received (tag response area).
Further, in the wireless tag detection system 1, the reader 101 extracts ID (recognition data) from the tag response received via the transmission / reception antenna 14 or the like in the reader processing (FIG. 4), and at least this ID is a tag. A read command included as data is generated.

  Therefore, according to such a wireless tag detection system 1, the command receiver 104 can receive at least the IDs of the wireless tags 102 and 103 received by the reader 101. Therefore, the command receiver 104 can recognize detailed information (information included in the tag data) of the wireless tags 102 and 103.

  Further, the reader 101 detects the presence or absence of the wireless tags 102 and 103 that have returned the tag response by detecting whether or not the tag response has been received via the transmission / reception antenna 14 or the like, and the detection result is the tag data. Read command included.

  Therefore, according to the wireless tag detection system 1 as described above, even if tag responses from the plurality of wireless tags 102 and 103 collide and the content of each tag response cannot be identified by the reader 101, the command receiver 104. Can be reliably detected if only the presence or absence of the wireless tags 102 and 103 is present.

  Further, the command receiver 104 determines whether or not the wireless tags 102 and 103 exist based on the tag data extracted in the receiver processing (FIG. 6). To the vehicle driver).

  Therefore, according to such a wireless tag detection system 1, it is possible to notify the user of the presence or absence of the wireless tags 102 and 103. In addition, for example, the command receiver 104 performs control of a device on which the command receiver 104 is mounted (control for suppressing the moving speed of the command receiver 104) based on the received tag data. However, since the command receiver 104 notifies the user of at least the presence or absence of the wireless tags 102 and 103, the user can recognize that the command receiver 104 controls the apparatus.

  Further, the reader 101 is configured to generate a read command in which tag data includes detection results of presence / absence of the wireless tags 102 and 103 that have sent back tag responses and detection results of whether or not the IDs have been successfully extracted. If the extraction means that the command receiver 104 has the wireless tags 102 and 103 that have sent back tag responses and the ID means that the ID has not been successfully extracted is obtained by the extraction means, The first detection information indicating that there are a plurality of 103 is notified to the user of the command receiver 104, and there is an extraction result indicating that there are wireless tags 102 and 103 that have sent back tag responses and that the ID has been successfully extracted. If so, the user of the command receiver 104 is notified of the second detection information representing the contents of the tag data including the ID.

  Therefore, according to such a wireless tag detection system 1, when the command receiver 104 receives from the reader 101 that a collision has occurred in the tag response from the wireless tags 102 and 103, there is a possibility of some collision. The first detection information that there is is transmitted to the user, and the user is predicted for danger. Further, when receiving from the reader 101 that the ID included in the tag responses from the wireless tags 102 and 103 has been detected, the command receiver 104 uses detailed second detection information such as the presence of a bicycle. Can tell. Further, it is possible to give the user a margin for dealing with the danger and to issue a warning that the user can deal with more safely.

  Further, the wireless tags 102 and 103 are at least carried by pedestrians as IDs, or are mounted on bicycles, motorcycles, or automobiles (types of vehicles on which the wireless tags 102 and 103 are mounted). ) Is transmitted. Further, the reader 101 generates a read command including the mounting information received from the wireless tags 102 and 103 as tag data, and the command receiver 104 is based on the mounting information included in the reading command received from the reader 101. The user of the command receiver 104 is notified of the presence or absence of a pedestrian, bicycle, motorcycle, or automobile.

  Therefore, according to such a wireless tag detection system 1, it is possible to notify the user of the command receiver 104 whether the reader 101 has detected a pedestrian, a bicycle, a motorcycle, or an automobile.

  In addition, according to the wireless tag detection system 1 as described above, since the reader 101 is installed at an intersection or the like, other pedestrians, bicycles, motorcycles, and automobiles approach the intersection on the vehicle on which the command receiver 104 is mounted. It is possible to notify the approach information indicating that it is in progress. Since the command receiver 104 warns the user based on this approach information, it is possible to prevent a traffic accident at a location where the reader 101 such as an intersection is arranged.

[Second Embodiment]
Next, another form of the wireless tag detection system 2 will be described. In the present embodiment, only portions different from the RFID tag detection system 2 of the first embodiment will be described in detail, and the same components as those of the RFID tag detection system 1 of the first embodiment will be denoted by the same reference numerals and described. Omitted.

  In the wireless tag detection system 2 (not shown) of the second embodiment, the configuration of the reader 201, the reader 201, the wireless tags 102 and 103, and the command are compared with the wireless tag detection system 1 of the first embodiment. Various processes executed by the receiver 104 are different. Here, FIG. 8 is a block diagram showing a schematic configuration of the reader 201 in the wireless tag detection system 2 of the second embodiment.

  In the reader 201 of this embodiment, the power amplifier 12 of the reader 101 described with reference to FIG. 3 is replaced with a variable gain power amplifier 17. As a result, the control circuit 10 transmits a transmission power control signal for changing the output of the read command to the variable gain power amplifier 17. As a result, the reader 201 can control the output of the read command and can control the range in which the read command is transmitted.

This example will be described below. Note that the transmitting / receiving antenna 14 of the reader 201 in the second embodiment also has radio wave characteristics as shown in FIG.
Here, an area where the radio waves of the reader 201 reach in the second embodiment is illustrated as shown in FIG. 9, for example. FIG. 9 shows a state where the intersection is viewed from above, and is an example in which a reader 201 is installed at the intersection angle and a reading command is transmitted diagonally to the upper right in the figure.

  The control circuit 10 of the reader 201 controls the variable gain power amplifier 17 based on the flag value of the transmission area R described later, and switches the transmission power to three stages. Then, the range in which the wireless tags 102 and 103 operate, that is, the area where the wireless tags 102 and 103 can respond (tag response area or receivable region) varies as 201, 202, and 203. At this time, areas (command receiver detection areas) where the command receiver 104 can receive and analyze the read command of the reader 101 vary as 211, 212, and 213, respectively.

  As can be seen from this figure, the command receiver 104 can receive a read command in a wider range than the range to which the wireless tags 102 and 103 respond, for example, a pedestrian or bicycle approaching from the road above the page. It is possible to detect from a vehicle traveling on the road on the left and right of the page.

  Further, the reader 201 can control the detection range of the wireless tag by controlling the output (transmission power) of the read command. For example, when there are many people, the transmission power is weakened and walking in the vicinity. Control is possible to detect only pedestrians and increase transmission power when there are fewer people to detect more distant pedestrians and bicycles.

  Next, a specific example of the read command transmitted from the reader 201 and the tag response by the wireless tags 102 and 103 in the second embodiment will be described. FIG. 10A is an explanatory diagram showing the configuration of the read command, and FIG. 10B is an explanatory diagram showing the configuration of the tag response.

  The read command in the present embodiment includes header information 91, a read result 92, and reader installation information 93. The header information 91 is provided with a preamble consisting of a known number sequence indicating the head of data and three flag information of E, S, and R. These three flag information are all single-digit integer values.

  In particular, E indicates a wireless tag detection flag indicating whether or not a wireless tag has been detected in the previous reading. Examples of the wireless tag detection flag include 0: no wireless tag, 1: wireless tag (only one exists, The meaning of “successful ID reading”, 2: wireless tag present (multiple presence, collision detection) may be defined.

  S is a sequence number when a series of readings are counted as one sequence to change the transmission power from a low state to a high state, and the value of S is sequentially increased to 1, 2, 3,... Smax. . It should be noted that if the predetermined upper limit sequence number Smax is exceeded, the process may be repeated from 1.

  R indicates an area division when the transmission power is changed. For example, when the transmission power is controlled in three stages as shown in FIG. 9, it may be defined as 1: transmission area narrow 2: in transmission area 3: transmission area wide.

  Next, the read result 92 included in the read command holds detailed information of the wireless tags 102 and 103 recognized by the reader 201 in the previous reading. That is, as the read result 92, for each transmission area, the type of the representative wireless tag detected in that area (eg, pedestrian or bicycle), the state of the wireless tag (stationary or moving, or not yet) Whether or not there is any other wireless tag (if a collision is detected, a plurality of wireless tags are considered to be present, so that the other wireless tag is “present”) is stored.

  The reader installation information 93 included in the read command includes, for example, the latitude / longitude of the place where the reader is installed, the design value of the maximum distance at which the reader 201 can detect the wireless tags 102 and 103, and the transmission area The number of area divisions (3 in the example of FIG. 9) and the direction in which the read command is transmitted (for example, north-northeast: NNW) are stored.

After the above commands are transmitted, the transmission command is completed by transmitting an end identifier indicating that the command has finally ended.
As described above, by including the reading result of the wireless tags 102 and 103 and the reader installation information in the reading command, it is possible to notify the command receiver 104 of the presence and position of the wireless tags 102 and 103. Become.

  Next, as shown in FIG. 10B, the tag responses of the wireless tags 102 and 103 are composed of the wireless tag type, ID, and wireless tag state. The wireless tag type is, for example, the wireless tags 102 and 103. Describes whether the vehicle is a pedestrian, a bicycle, or a motorcycle.

The ID is a number for distinguishing the wireless tags 102 and 103 from the other wireless tags 102 and 103 and is the same as that mounted on the general wireless tags 102 and 103.
The wireless tag state is used particularly for the semi-passive type wireless tag 103 described with reference to FIG. 3, and notifies whether the wireless tag is stationary or moving based on the state of the speed sensor 35. In addition, the control circuit 33 is configured so that the wireless tag 103 is a reader based on the position information of the reader 201 included in the read command, the position information by the speed sensor 35, the azimuth sensor 36, and the GPS receiver 37 and the information on the moving direction. It is also possible to calculate whether the speed is approaching or moving away, and what is the speed, and transmit the result of the calculation as a wireless tag state.

Next, in the wireless tag detection system 2, the reader 201, the wireless tags 102 and 103, and the command receiver 104 execute processing as described below.
First, FIG. 11 is a flowchart showing reader processing executed by the control circuit 10 of the reader 201.

  In the reader processing of this embodiment, the flags (wireless tag detection flag E, sequence number S, area classification R) described in FIG. 10A are changed to initial values (S410), and the changed values are changed. Set and transmit (S415), and wait for a tag response from the wireless tags 102 and 103 (S420).

  When tag responses from the wireless tags 102 and 103 are detected (S420: Yes), it is determined whether or not there is a data error (whether the tag response has been received normally) (S425). If a data error has occurred (S425: Yes), the RFID tag detection flag E is set to 2 (“collision”) as a collision has occurred (S430), and the other corresponds to the current transmission area R. Information indicating whether or not the wireless tags 102 and 103 are present is set to “exist” (S435), and the process returns to S415.

  On the other hand, if no data error has occurred in S425 (S425: No), the wireless tag detection flag E is set to 1 (“reading success”) assuming that there is a single response from the wireless tags 102 and 103. (S440), the data acquired from the wireless tags 102 and 103 is written in the part corresponding to the area R of the read result 92 (S445), and the process proceeds to S465.

  Next, when the tag response from the wireless tags 102 and 103 cannot be detected in the process of S420 (S420: No), the wireless tag detection flag E is set to 0 (“not present”) (S450). . Then, it is determined whether or not the read command transmission process in S415 is the first transmission in the area section R (S455). In this determination, although not shown, the counter value may be referred to when the area division R is changed and is reset every time the transmission process in S415 is executed.

  Here, in the case of the first transmission in the area section R, it means that there was no response in the first transmission. In other words, as will be described later, the wireless tags 102 and 103 are set to always return a tag response when receiving a read command from the reader 201 for the first time, so there was no response in the first transmission. Is detected, it means that there is no wireless tag in the area R.

  Therefore, when the transmission process in S415 is the first transmission in the area section R (S455: Yes), the wireless tag detection flag E in the area R of the read result 92 is set to 0 (“not present”) (S460). , The process proceeds to S465.

  On the other hand, if it is not the first transmission in the area division R in S455, the tag responses from the wireless tags 102 and 103 collide once, and there is no response from the wireless tags 102 and 103 due to the second and subsequent reading requests. Means that. That is, as will be described later, since the wireless tags 102 and 103 use a procedure for avoiding collision of tag responses using random numbers, if it is determined in S455 that the transmission is not the first transmission in the area section R, It can be considered that all the existing wireless tags 102 and 103 stop responding depending on the situation of random numbers generated in the wireless tags 102 and 103.

  Here, if the reading command is repeatedly transmitted from the reader 201 in this state, the wireless tags 102 and 103 can be expected to return a response again. In the present embodiment, the wireless tags 102 and 103 are described in detail. Since it is more important to detect whether or not the wireless tags 102 and 103 exist than to read the recognition information, priority is given to detecting the wireless tags 102 and 103 at high speed.

  Therefore, if it is not the first transmission in the area section R (S455: No), the process proceeds to the next area expansion process (S465). In this case as well, the presence / absence of the other wireless tags 102 and 103 in the read result 92 in the area classification R before the area expansion remains “exist”, so that the command receiver 104 to be described later is notified. On the other hand, it can be notified that the wireless tags 102 and 103 exist in the area division R before the area expansion.

  In the area enlargement process (S465), the area division R is enlarged by one step (R is incremented), and it is determined whether or not the changed area division R exceeds the maximum area Rmax (S470). If the changed area section R does not exceed the maximum area Rmax (S470: No), the process returns to S415 as it is.

  On the other hand, if the area segment R after the change exceeds the maximum area Rmax (S470: Yes), the sequence number S is updated (S is incremented) and the area is reset (R is set to 1) because the sequence is completed. Set) (S475). Subsequently, it is determined whether or not the updated sequence number S exceeds the maximum sequence number Smax (S480).

When the updated sequence number S exceeds the maximum sequence number Smax (S480: Yes), the sequence is returned to 1 (S490), and the process returns to S415.
When the updated sequence number S does not exceed the maximum sequence number Smax (S480: No), the process returns to S415 as it is.

  Next, FIG. 12 is a flowchart showing a wireless tag process executed by the control circuit 23 (33) of the wireless tag 102 (103) of the second embodiment. Here, an area variable r for holding the area section R transmitted by the reader 201 together with the command, a sequence variable s for holding the sequence number S, and a counter c for avoiding collision are used. .

  This wireless tag process is started when the wireless tags 102 and 103 are activated. First, the area variable r, the sequence variable s, and the counter c are set to initial values (that is, 0) (S510) and received. Wait (S515). When the read command can be received, the header information 91 of the read command is acquired, and the wireless tag detection flag E, the area classification R, and the sequence number S included in the header information 91 are set as Er, Rr, and Sr, respectively. (33) (memory means: configured as a flash memory, for example) (S520). That is, the value of each flag included in the header information 91 is held for each area variable r in association with the area variable r.

  Subsequently, by comparing the value of Sr with s held in the wireless tag, it is determined whether or not the wireless tags 102 and 103 receive the read command in the current sequence for the first time (S525). If it is the first time (s ≠ Sr, S525: Yes), the area section Er and the sequence number Sr are stored (S530, S535), and the counter c is cleared (S540).

  Subsequently, a response is returned (S545), and the process returns to S515. By such processing, when a read command at a certain sequence number S is first received, the tag response can be surely returned after the information is temporarily stored.

  On the other hand, if there is a history that the wireless tags 102 and 103 have received the read command at the sequence number S (s = Sr, S525: Yes), whether or not a tag response should be transmitted in this area section R is determined. Judgment is made (S550). At this time, if the held area r and the area section R written in the read command header are different (r ≠ Rr, S550: No), the reader 201 uses another area section R in this sequence. Therefore, the tag response from the wireless tags 102 and 103 has already been received. Therefore, the wireless tags 102 and 103 return to the processing of S515 without transmitting the tag response, assuming that it is not necessary to transmit the tag response in the area division R.

  In addition, if the held area r is different from the area R written in the read command header (r ≠ Rr, S550: No), it means that a wireless tag collision has occurred in the previous response. Therefore, the procedure proceeds to the collision avoidance procedure surrounded by a dotted line in the figure. In the collision avoidance procedure, first, it is determined whether the reader 201 has detected the wireless tags 102 and 103 (S555). Here, the wireless tag detection flag E is referred to, and if E is 1 or more (1 or 2), it is determined that any wireless tag 102 or 103 is detected by the reader 201.

  When the reader 201 detects the wireless tags 102 and 103 (S555: Yes), it is determined that tag responses from the plurality of wireless tags 102 and 103 collide on the reader 201 side. In this case, first, it is determined whether or not the counter c is 0 (S560). If the counter c is not 0 (S560: No), the counter is added (S580), and the process returns to S515.

If the counter c is 1 (S560: Yes), the state of the wireless tag is detected and the random frequency is set (S565), and a random number of 0 or 1 is generated (S570).
Subsequently, it is determined whether or not the random number is 1 (S575). If the random number is 1 (S575: Yes), the counter is incremented (S580), and the process returns to S515 without transmitting a tag response. If the random number is 0 (S575: No), a tag response is transmitted (S585), and the process returns to S515.

  Here, in the process of S565, when the ID of the wireless tag 103 is an ID assigned to, for example, a thing mounted on a bicycle, the probability that 0 is generated compared to the wireless tag 102 carried by the pedestrian. (Probability of transmitting a tag response) is increased, and when the speed sensor of the wireless tag 103 mounted on the bicycle determines that the corresponding bicycle is moving, a process of further increasing the probability of 0 is added. Accordingly, when there are a plurality of wireless tags 102 and 103, it is possible to set so that a bicycle, and further a moving bicycle, responds with a higher probability than a pedestrian.

  In S555, when it is detected that the reader 201 has not detected the wireless tags 102 and 103 (S555: No), in the collision avoidance process, a plurality of wireless tags 102, It is thought that all 103 happened to be unanswered. Therefore, the wireless tags 102 and 103 decrement the counter c (decrement c) (S590), and determine whether the counter c is 0 or less (S595).

  If the counter c is 0 or less (S595: Yes), a tag response is transmitted (613), and the process returns to S515. If the counter c is not less than 0 (S595: No), the process returns to S515 as it is.

  Next, FIG. 13 is a flowchart illustrating receiver processing executed by the command analysis unit 51 of the command receiver 104 according to the second embodiment. Here, a counter C that manages the number of reception processes and a detection flag G that indicates whether or not the wireless tags 102 and 103 have been detected in the previous reception are used.

  The receiver process is started when the power of the command receiver 104 is turned on. First, the counter C and the detection flag G are cleared. That is, the counter C is set to 0, and the detection flag G is set to 0 (S610).

  Then, a process of receiving and analyzing the read command from the reader 201 is performed (S615), and it is determined whether or not the read command is received from the reader 201 within a preset designated time (S620). If no read command is received from the reader 201 within the specified time (S620: No), the counter C is incremented (S625), and the value of the counter C (number of reception trials) is set to a preset number of times Cmax. It is determined whether it has been exceeded (S630).

  If the value of the counter C exceeds the specified number of times Cmax (S630: Yes), the counter C and the detection flag G are cleared (S635), and the process returns to S615. If the value of the counter C does not exceed the specified number of times Cmax (S630: No), the process returns to S615 as it is.

  If a read command is received from the reader 201 within the specified time in S620 (S620: Yes), the counter C is cleared (S640). Then, whether or not the presence of the wireless tags 102 and 103 is described in the reading result 92 of the reader 201 (a specific wireless tag detection result is written or another wireless tag is “existing”). Whether or not) is determined (S645).

  If the presence of the wireless tags 102 and 103 is described (S645: Yes), it can be seen that the wireless tags 102 and 103 exist in the vicinity of the reader 201 (area corresponding to the area section R). Therefore, the detection flag G is used to determine whether this is the first detection. That is, it is determined whether or not the detection flag G is 0 (S655).

  If this is the first detection (G = 0, S655: Yes), an alarm as shown in S355 or S360 is output (S660), the detection flag G is set to 1 (S665), and the process of S615 Return to.

  If it is not the first detection in S655 (G ≠ 0, S655: No), the detection content is updated (S670), and the process returns to S615. In S670, the troublesomeness caused by repeatedly sounding the alarm is eliminated by limiting the processing to update the detected content.

  Further, in S645, when the reading result 92 by the reader 201 does not describe the presence of the wireless tags 102 and 103 (S645: No), the detection flag G and the detection contents on the detection result display unit 55 are detected. The display is cleared (S650), and the process returns to S615.

  Subsequently, in order to describe the operation of the second embodiment more specifically and in detail, the reader 201 and the wireless tag 102 are executed according to the transmission range of the read command and the presence of the wireless tags 102 and 103. 103, exchange of information between the command receiver 104 will be described.

  FIG. 14 is an explanatory diagram showing an example of the existence state (existing position) of the wireless tags 102 and 103. FIG. 14A shows an example in which wireless tags exist in all the transmission areas set in three stages. On the other hand, FIG. 14B shows an example in which no wireless tag exists in the transmission area 201 closest to the reader 201.

  14 (a) and 14 (b), although not shown, as shown in FIG. 9, the command reception is received in the command receiver detectable area when the area division R is 1. It is assumed that there are two vehicles 107a and 107c equipped with the machine 104, and that one vehicle 107b exists in the command receiver detectable area when the area division R is 3.

  Next, an example of signals exchanged in each of the above processes in the present embodiment and a command receiver 104 that has received a read command from the reader 101 analyzes the command to know the presence of a pedestrian or a bicycle. An example of processing is shown. FIG. 15 is a ladder chart showing signal exchange executed in the reader process, the RFID tag process, and the receiver process in the state of FIG.

  First, the reader 201 transmits a read command toward the transmission area 1 (area division R = 1) (S701). At this time, since only the wireless tag 102a exists in the transmission area 1, the wireless tag 102a responds, and the wireless tag 102a is successfully detected by the reader 201 (S702).

  Next, the reader 201 widens the transmission area, sets it so as to reach the transmission area 2 (area division R = 2), and transmits. At this time, the wireless tag detection flag E is set to 1 to notify the presence of the wireless tag 102a, and the information of the wireless tag 102a detected earlier is described in the read result 92 and transmitted (S703).

  Since the command receivers 104a and 104c that have received the read command know that the wireless tag 102a (that is, the pedestrian) exists in the transmission area 1, the command receivers 104a and 104c notify that the pedestrian exists.

  In addition, the wireless tag 102a does not respond to the read command for the transmission area 2, but the wireless tags 102b, 103a, 102c, and 102d located in the transmission area 2 receive the reception signal for the first time and return the response all at once. A collision occurs in the tag response received by the reader 201 (S704). Therefore, the reader 201 notifies the occurrence of a collision by setting the wireless tag detection flag E = 2, and additionally transmits another read command by setting another wireless tag in the transmission area 2 to “exist” in the read result 92 ( S705).

  The command receiver 104 that has received this read command can obtain information that there are pedestrians in the transmission area 1 and that there are a plurality of pedestrians or bicycles in the transmission area 2, so that an alarm is provided accordingly. And a warning.

  On the other hand, the wireless tags 102b, 103a, 102c, and 102d that have received this read command determine response / non-response with random numbers according to the collision avoidance process described with reference to FIG. As a result, for example, when it is assumed that only the wireless tag 103a mounted on the bicycle responds (S706), the reader 201 updates the reading result 92 based on the information of the 103a. There are also other wireless tags ", and the transmission area is further expanded to transmit a read command (S707).

By this read command, the read command reaches not only the command receivers 104a and 104c but also the command receiver 104b, and updates and notifies the result of each alarm.
Thereafter, similar processing is continued (S708, S709, S710), and the processing of sequence 1 is completed. Thereafter, the sequence 2 is started. The first command of the sequence 2 includes the last detection result of the sequence 1 (S711), and the command receiver 104 that has received the result detects the wireless tags 102 and 103. You can know the existence quickly.

  As shown in the flowchart of the reader 201 described with reference to FIG. 11, the detection result is cleared when the wireless tags are all moved away from the transmission area of the reader after the sequence 2 and no wireless tags exist. .

Next, FIG. 16 is a ladder chart showing signal exchange executed in the reader process, the wireless tag process, and the receiver process in the state of FIG.
In this example, since the wireless tags 102 and 103 are not in the transmission area 1, the read command in S751 reaches the command receivers 104a and 104c, but the value of each flag included in this read command is determined by the wireless tag detection flag E. 0 and the other wireless tag of the reading result 92 is not present. For this reason, the command receiver 104 does not notify a warning or alarm.

  After that, when a plurality of wireless tags 102 and 103 respond to the read command in S753 and a collision occurs in the tag response, the fact that another wireless tag 102 or 103 exists in the transmission area 2 is set and read. The device 201 transmits a read command (S755). As a result, since the command receivers 104a and 104c know that there are pedestrians or bicycles in the transmission area 2, detailed identification has not been made, but a notice that “a plurality of pedestrians or bicycles exist” is provided. Can be notified.

  Thereafter, in the collision avoidance process in the wireless tags 102 and 103, when both of the wireless tags 102b and 102c happen to return no response, the reader 201 completes transmission of the transmission area 2 as described above. The process proceeds to transmission in the transmission area 3. In this example, it is not possible to accurately detect whether the transmission area 2 is a pedestrian or a bicycle after all, but the presence of the plurality of wireless tags 102 and 103 indicates that the command receiver 104 is present. It is enough because it can be notified.

  Furthermore, if the wireless tags 102 and 103 are still positioned in the vicinity of the reader 201 when proceeding to the next sequence thereafter, the possibility of being able to be recognized correctly in the next and subsequent sequences increases. Can be effectively used for the purpose of preventing traffic accidents.

In the present embodiment, the reader process (FIG. 11) corresponds to the area changing means (S465) in the present invention.
The wireless tag processing (FIG. 12) corresponds to the movement detecting means (S565) and the probability changing means (S570) in the present invention.

  In the RFID tag detection system 2 described in detail above, the reader 101 sequentially expands the receivable area of the read command in the reader process (FIG. 11), and area information indicating the receivable range of the read command. Is generated in the tag data.

  Therefore, according to the wireless tag detection system 2 as described above, the command receiver 104 extracts the area information from the tag data of the read command to determine in which receivable area the wireless tags 102 and 103 exist. Can be detected.

  Further, according to the wireless tag detection system 1 as described above, the receivable area is sequentially expanded, so that the wireless tags 102 and 103 existing near the reader 201 can be detected at an early stage. For this reason, for example, if the reader 101 is arranged in a place where an accident is likely to occur, such as an intersection, and the wireless tags 102 and 103 are moved together with the pedestrian and the vehicle, the command receiver 104 can be connected to the wireless tags 102 and 103. Since the information can be received via the reader 101 in the order close to the intersection, the accident can be made difficult even in a place where the accident is likely to occur.

  Also, by setting the receivable area in order, it becomes easy to avoid the collision of tag responses that occur when all the wireless tags 102 and 103 respond simultaneously, and in particular, the wireless tags 102 and 103 are carried. The reading efficiency can be increased in a place where there are many pedestrians and vehicles equipped with the wireless tags 102 and 103.

  In the present embodiment, when the presence of the wireless tags 102 and 103 is detected by the reader 101 and the absence of the wireless tags 102 and 103 is detected in the receivable areas of the respective read commands. In addition, the coverage area is expanded to the next stage.

  For example, when the wireless tags 102 and 103 are used for logistics and merchandise management, it is important to read all the items with the wireless tags 102 and 103 attached. However, when the wireless tags 102 and 103 are used to notify the presence of pedestrians and other vehicles to help prevent traffic accidents, other vehicle users who are notified of the detection results are pedestrians in the vicinity. It is not necessary to know the number of vehicles or the number of vehicles, and information on whether or not they are present is important.

  For this reason, the reader 101 can quickly detect only the information on whether a pedestrian or vehicle having the wireless tags 102 and 103 in a certain receivable area is “present” or “not present” and Can be changed. Therefore, the detection speed of the wireless tags 102 and 103 can be improved, and information can be updated more quickly.

In particular, in the reader 201 of this embodiment, the receivable area is changed by changing the transmission output of the read command.
According to such a wireless tag detection system 1, if the transmission power from the reader 201 is weakened, only the wireless tags 102 and 103 located in the vicinity of the reader 201 can be detected, and if the transmission power is increased. The wireless tags 102 and 103 located further away can also be detected.

  Further, in the wireless tag detection system 1, the reader 201 transmits the read command while the receivable area is changed, and the number of executions of a series of transmission procedures before the read command is transmitted again in the first receivable area. A read command including a sequence number representing the tag data is generated. When receiving the read command, the wireless tags 102 and 103 analyze the tag data and send back a tag response only when it is detected that the sequence number included in the tag data has been changed. In this case, when receiving the read command, the wireless tags 102 and 103 analyze the tag data and detect that the sequence number included in the tag data is changed from the sequence number in the read command received last time. The area division R included in the data is stored and a tag response is sent back. Then, when it is detected that the sequence number is not changed from the sequence number in the read command received last time and the area segment R included in the tag data is changed from the stored area segment R, a response signal is sent back. I am trying not to.

  That is, if the reader 101 sequentially enlarges the receivable area and transmits a read command, the number of wireless tags 102 and 103 responding to the read command increases as the receivable area is enlarged, and the tag response collides. Probability increases. However, according to the configuration of the embodiment, the wireless tags 102 and 103 that respond to the read command do not respond when the area information is changed in the same sequence number, so even when sequentially expanding the receivable area, It is possible to reduce the collision of the tag response to the read command.

  Therefore, according to the wireless tag detection system 1 as described above, the possibility that the responses of the plurality of wireless tags 102 and 103 collide is reduced, and the detection time can be shortened. Can improve the receiving accuracy.

  In the wireless tag detection system 1, the wireless tags 102 and 103 are in a state in which the sequence number is not changed from the previous sequence number, and the area information included in the tag data is changed from the area information stored in the storage unit. When it is detected that there is no response, it is set whether or not to send back a response signal with a probability set in advance according to the type of the wireless tag.

  According to such a wireless tag detection system 1, it is possible to set a priority order for returning a tag response according to the type of the wireless tags 102 and 103. For this reason, for example, a high priority is set for the wireless tags 102 and 103 mounted on a bicycle that has a higher probability of an accident than a pedestrian or an object that moves at high speed, such as a motorcycle (the probability that a tag response is sent back is set higher). ), It is possible to preferentially detect an accident with a high probability of an accident.

  In addition, the wireless tags 102 and 103 are such that the wireless tag processing (FIG. 12) itself is moving at a speed equal to or higher than a preset threshold speed, or the wireless tags 102 and 103 approach the reader 101. If it is detected, the probability of sending back the tag response is changed to a higher probability.

  That is, in the wireless tag processing (FIG. 12), the wireless tags 102 and 103 that move at a speed equal to or higher than the threshold speed and the wireless tags 102 and 103 that are approaching the reader 101 are regarded as dangerous and a tag response is sent back. Set a higher priority.

  Therefore, according to the wireless tag detection system 1 as described above, the wireless tags 102 and 103 moving at a speed equal to or higher than the threshold speed and the wireless tags 102 and 103 approaching the reader 101 are detected with priority. Therefore, it is possible to prevent a person carrying the wireless tags 102 and 103 or a moving object equipped with the wireless tags 102 and 103 from contacting a moving object equipped with the command receiver 104 near the reader 101. can do. Therefore, if the reader 101 is arranged at a place where an accident is likely to occur, such as an intersection, the accident can be made difficult to occur.

Further, the reader 201 generates position information indicating the installation position of the reader 101 by including it in the read command.
Therefore, according to the RFID tag detection system 1 as described above, in the reader process (FIG. 4) of the reader 101, the position information indicating the installation position of the reader 101 and the area information indicating the transmission range of the read command. Therefore, the command receiver 104 can specify the area where the wireless tags 102 and 103 exist.

[Third Embodiment]
FIG. 17 shows the structure of a reader 301 used in the third embodiment of the present invention. Similar to the second embodiment, this reader is intended to control an area for transmitting a read command, but uses a multi-beam transmitting / receiving antenna 18 instead of changing the transmission power. .

  For example, the multi-beam transmitting / receiving antenna 18 has a configuration as shown in FIG. 18. The antenna is installed downward in an area close to the reader 301, and the antenna is installed in a distant area close to the ground.

  Here, since the transmission power is changed in the reader 201 of the second embodiment, for example, referring to FIG. 9, the response possible area of the wireless tags 102 and 103 is the transmission area 1 from the position of the reader 201 in the transmission area 1. From the reader 201 to the boundary of the area 2 in the transmission area 2, the very vicinity of the reader 201 was always included in the response possible area by the wireless tags 102 and 103.

  On the other hand, in the reader 301 of the third embodiment, the response area for the read command is changed by the antenna installation angle, so in the transmission area 1 from the very vicinity of the reader 301 to the boundary of the transmission area 1. However, in the transmission area 2, a donut-shaped (area excluding the transmission area 1) response possible area from the boundary of the transmission area 1 to the boundary of the transmission area 2 can be formed. Thereby, it is possible to suppress transmission of radio waves to an unnecessary range, and to more reliably suppress collision of tag responses from the wireless tags 102 and 103.

  The processing procedure of the reader, command receiver, and wireless tag shown in FIGS. 11 to 16 is the third implementation because the wireless tag that has responded once uses an algorithm that does not return a response even if the area is expanded thereafter. A common processing procedure can also be used in the form.

  If the reading command is transmitted downward from the reader 301 like the reader 301 described in detail above, only the wireless tags 102 and 103 located in the vicinity of the reader 101 can be detected, and the angle is reduced. If the reading command is transmitted in parallel with the road surface, the wireless tags 102 and 103 located farther can be detected.

[Fourth Embodiment]
FIG. 19 shows a fourth embodiment of the present invention. In the first embodiment, it is assumed that the wireless tags 102 and 103 are held by pedestrians and bicycles. However, in this embodiment, in addition to this, the wireless tag 105 (105a, 105b) is mounted on a motorcycle and the wireless tag is wirelessly connected. The tag 106 (106a-106c) was mounted in the automobile. Note that these wireless tags 105 and 106 can be of a semi-passive type.

  Further, the command receiver 104 may be mounted not only on the automobile but also on a motorcycle (command receiver 104d). According to this embodiment, an automobile or a motorcycle can detect the approach of each other, and can be used for an application that prevents a entanglement accident or a collision accident at an intersection.

[Fifth Embodiment]
FIG. 20 shows a fifth embodiment of the present invention. In this embodiment, the command receiver 504 is devised, and a signal from the GPS receiver 57 (current location detection means) is newly used. In this embodiment, the command receiver 504 also uses the reader installation information 93 among the read commands transmitted by the reader 201.

  As already described with reference to FIG. 10A, the reader installation information 93 includes the installation position of the reader 201 and the irradiation direction of radio waves. For example, if the positional relationship between the reader 201 and the command receiver 504 is detected together with the installation information 93 based on the result of determining the position of the vehicle by the GPS receiver 37 (position relationship detecting means), “the own vehicle is , Traveling north on a road south of an intersection, the reader is located north of itself and transmits radio waves eastward. The maximum transmission distance is 30 m and the information is divided into three transmission areas. At this time, if it is written in the reading result 92 of the reader 201 that “there is a pedestrian in the area 1”, from this information, “the pedestrian is detected within 10 m on the left side of the intersection on the left side” The driver can be notified more specifically, including the relative relationship with

  Further, when the wireless tag 103 is not moving in the direction of the intersection (the direction of the reader 201) by detecting the positional relationship between the command receiver 504 and the wireless tag 103 and the moving direction of the wireless tag 103, , You can turn off the warning.

[Other Embodiments]
The embodiment of the present invention is not limited to the above-described embodiment, and can take various forms as long as it belongs to the technical scope of the present invention.

  For example, in the wireless tag detection system 1 in the above-described embodiment, the passive or semi-passive type is used as the wireless tags 102 and 103. However, even an active type wireless tag that is equipped with a power source and actively transmits radio waves by itself is used. The features of the invention can be realized.

  In the collision avoidance process in the second embodiment, a process for setting a random number frequency and a process for generating a random number are performed. However, other procedures may be used for collision avoidance. However, in this case, in order to preferentially detect an object with a high moving speed (that is, an object that is likely to cause danger to the vehicle), a bicycle from a pedestrian and a moving bicycle are more It is desirable to set the processing so as to obtain a right to transmit a tag response with a high priority.

It is explanatory drawing which shows the outline | summary of the radio | wireless tag detection system of 1st Embodiment. It is explanatory drawing which shows the electromagnetic wave transmission characteristic transmitted / received from the transmission / reception antenna of the reader of 1st Embodiment. It is a block diagram which shows schematic structure of the reader of 1st Embodiment, a radio | wireless tag, and a command receiver. It is a flowchart which shows the reader process of 1st Embodiment. It is a flowchart which shows the radio | wireless tag process of 1st Embodiment. It is a flowchart which shows the receiver process of 1st Embodiment. It is a ladder chart which shows the exchange of the signal performed in a reader process, a radio | wireless tag process, and a receiver process. It is a block diagram which shows schematic structure of the reader in the wireless tag detection system of 2nd Embodiment. It is explanatory drawing which shows the example which transmits a reading command toward the diagonally upper right in the figure from the reader installed in the intersection angle | corner. It is explanatory drawing which shows the specific example of the read command transmitted from the reader in 2nd Embodiment, and the tag response by the wireless tags 102 and 103. FIG. It is a flowchart which shows the reader process of 2nd Embodiment. It is a flowchart which shows the radio | wireless tag process of 2nd Embodiment. It is a flowchart which shows the receiver process of 2nd Embodiment. It is explanatory drawing which shows an example of the presence state (presence position) of a wireless tag. FIG. 15 is a ladder chart showing signal exchange executed in the reader process, the wireless tag process, and the receiver process in the state of FIG. FIG. 15 is a ladder chart showing signal exchange executed in the reader process, the wireless tag process, and the receiver process in the state of FIG. It is a block diagram which shows schematic structure of the reader in 3rd Embodiment. It is explanatory drawing which shows schematic structure of the multi-beam transmission / reception antenna of 3rd Embodiment. It is explanatory drawing which shows the outline | summary of the radio | wireless tag detection system of 4th Embodiment. It is a block diagram which shows schematic structure of the command receiver in the radio | wireless tag detection system of 5th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... RFID tag detection system, 10 ... Control circuit, 11 ... Modulator, 12 ... Power amplifier, 13 ... Circulator, 14 ... Transmission / reception antenna, 15 ... Reception amplifier, 16 ... Demodulator, 17 ... Variable gain power amplifier, 18 ... Multi-beam transmitting / receiving antenna, 21 ... transmitting / receiving antenna, 22 ... reflective modulator, 23 ... control circuit, 24 ... rectifier circuit, 32 ... reflective modulator, 33 ... control circuit, 34 ... power supply, 35 ... speed sensor, 36 ... Direction sensor 37 ... GPS receiver 51 ... Command analysis unit 52 ... Demodulator 53 ... Reception amplifier 54 ... Reception antenna 55 ... Detection result display unit 56 ... Warning output unit 57 ... GPS receiver 91 ... header information, 92 ... reading result, 93 ... reader installation information, 101 ... reader, 102 ... wireless tag, 103 ... wireless tag, 104 ... command receiver, 105 ... Line tag, 106 ... wireless tag, 107a ... vehicle, 107 b ... vehicle, 201 ... reader, 301 ... reader, 504 ... command receiver.

Claims (15)

A radio tag having response means for sending back a response signal including at least its own recognition data by radio to a specific transmission signal transmitted by radio;
Receiving means for receiving a response signal sent back from the wireless tag, signal generating means for generating a transmission signal including tag data corresponding to the response signal received by the receiving means, and transmission generated by the signal generating means A reader having transmission means for transmitting a signal;
A receiving device having an extraction means for receiving a transmission signal transmitted from the reading device and extracting tag data from the transmission signal;
A wireless tag detection system comprising: The signal generation unit of the reading device extracts the recognition data from a response signal received via the reception unit, and generates a transmission signal including at least the recognition data as the tag data. The wireless tag detection system according to 1. The signal generation means of the reader detects whether or not there is a wireless tag that has sent back a response signal by detecting whether or not a response signal has been received via the receiving means, and the detection result is included as the tag data The wireless tag detection system according to claim 1, wherein the transmission signal is generated. The receiving device is provided with notifying means for notifying a user of the receiving device of at least information on whether or not a wireless tag is present based on the tag data extracted by the extracting means. The wireless tag detection system according to any one of claims 1 to 3. The signal generation means of the reader detects whether or not there is a wireless tag that has sent back a response signal by detecting whether or not a response signal has been received via the receiving means, and when the response signal is received The recognition data is extracted from the response signal, it is detected whether the recognition data has been extracted normally, the detection result of the presence or absence of the wireless tag that has sent back the detected response signal, and the recognition data is normal The detection result of whether or not it can be extracted is configured to generate a transmission signal included as the tag data,
The extraction unit of the receiving device determines whether or not the detection result of the presence / absence of the wireless tag that sent back the response signal and the recognition data have been normally extracted from the tag data included in the transmission signal received from the reading device. Extract the detection results,
The notifying means of the receiving apparatus has a wireless tag that has sent back the response signal, and if the extraction means that the recognition data has not been successfully extracted is obtained by the extracting means, the wireless device that has sent back the response signal. A first detection information indicating that there are a plurality of tags is notified to the user of the receiving device, and there is a wireless tag that sends back the response signal, and an extraction result indicating that the recognition data has been successfully extracted is the extraction result. The wireless tag detection system according to claim 4, wherein if obtained by the means, the second detection information indicating the content of the tag data including the recognition data is notified to a user of the receiving device. The wireless tag response means transmits, as the recognition data, at least information held by a pedestrian or mounted on a bicycle, a motorcycle, or an automobile.
The signal generation means of the reader generates a transmission signal including the mounting information received from the wireless tag as the tag data,
The notifying means of the receiving device notifies the user of the receiving device of the presence or absence of a pedestrian, bicycle, motorcycle, or automobile based on the mounting information included in the transmission signal received from the reading device. The wireless tag detection system according to claim 4 or 5, characterized in that The reader is
Comprising an area changing means for changing a receivable area of a transmission signal transmitted by the transmitting means;
The said signal generation means produces | generates the transmission signal which included the area information showing the transmission range of the transmission signal by the said range change means in the said tag data. Wireless tag detection system. The wireless tag detection system according to claim 7, wherein the area changing unit changes the receivable area by causing the transmission unit to change a transmission output of a transmission signal. The wireless tag detection system according to claim 7 or 8, wherein the region changing unit changes the receivable region by causing the transmitting unit to change a transmission signal transmission angle.   The wireless tag detection system according to any one of claims 7 to 9, wherein the area changing unit sequentially expands the receivable area. The signal generation means of the reading device transmits the transmission signal by the transmission means while the receivable area is changed by the area changing means, and again before the transmission signal is transmitted by the transmission means in the first receivable area. A transmission signal including a sequence number representing the number of times of execution of a series of transmission procedures up to the tag data,
The wireless tag response means includes:
When the transmission signal is received, the tag data is analyzed, and when it is detected that the sequence number included in the tag data is changed from the previous sequence number, the area information included in the tag data is stored in the storage means. And sending back the response signal,
When it is detected that the sequence number is not changed from the previous sequence number and the area information included in the tag data is changed from the area information stored in the storage means, the response signal is sent back. The wireless tag detection system according to claim 10, wherein the wireless tag detection system is not provided. The wireless tag response means indicates that the sequence number has not been changed from the previous sequence number, and that the area information included in the tag data has not been changed from the area information stored in the storage means. 12. The wireless tag detection system according to claim 11, wherein upon detection, it is set whether or not to send back the response signal with a probability set in advance according to the type of the wireless tag. The wireless tag is
Movement detecting means for detecting that the wireless tag is moving at a speed equal to or higher than a preset threshold speed, or that the wireless tag is approaching the reader;
When the movement detection means detects that the wireless tag is moving at a speed equal to or higher than the threshold speed or is approaching the reader, the probability that the response signal is sent back is higher. A probability changing means for changing to
The wireless tag detection system according to claim 12, further comprising: The wireless tag detection according to any one of claims 7 to 13, wherein the signal generation means of the reader generates at least position information indicating an installation position of the reader included in the transmission signal. system. The receiving device is:
Current location detection means for detecting the current location of the receiving device;
A positional relationship detecting unit that detects a positional relationship between the receiving device and the wireless tag based on the current location detected by the current location detecting unit and the positional information received from the reading device;
The wireless tag detection system according to claim 14, further comprising:

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