JP2007117176A - Racing time counting system, wireless device and time transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a racing time counting system capable of appropriately counting a racing time of each player while suppressing the generation of collision. <P>SOLUTION: A wireless tag 50 detects a time-counting point based on increase/decrease of the strength of an electromagnetic field generated on a loop antenna 20 and specifies a racing time. The wireless tag 50 selects a channel to be used according to the racing time, determines a busy state in the selected channel and appropriately waits till the wireless communication becomes possible. When the wireless communication becomes possible, the wireless tag 50, for example, appropriately staggers the transmission timings of a first time from the second time or more and transmits the racing times or the like to a receiver 30. On the other hand, the receiver 30 receives at least a single racing time or the like for every wireless tag 50 out of the racing times or the like transmitted a plurality of times from the respective wireless tags 50 for every channel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a competition timing system, a wireless device, and a time transmission method capable of appropriately timing the competition time of each athlete while suppressing the occurrence of collision.

In recent years, in marathon competitions, attempts have been made to measure (clock) the goal time of each individual athlete. For example, a measurement system that measures a competitor's individual goal time based on the time when a barcode was printed on a competitor's race bib and the reader's barcode was read by a reader has been put into practical use. Yes.
Recently, in order to be able to measure the competition time including the passing time at each timing point, an attempt has been made to measure the competition time of each athlete without contact. For example, a measurement system for measuring a competition time has been developed based on information sent from the tag transmitter by allowing a player to hold a tag transmitter, and an operation test for practical use has been attempted.

More specifically, a trigger signal is transmitted from a square loop coil or the like into the measurement area on the competition track, and when the athlete holding the tag transmitter travels within the measurement area, In response, an ID (such as an identification number) is transmitted from the tag transmitter. And ID receiving unit receives this ID, and measures the number of laps of each athlete, competition time, etc. (for example, refer to patent documents 1).
In addition to this, a technique is also disclosed in which the tag transmitter transmits an ID using weak radio waves in the UHF band, etc., so as to increase the communication distance of the tag transmitter (see, for example, Patent Document 2).
JP 2003-141497 A (page 2-4, FIG. 2) JP 2004-125765 A (page 3-4, FIG. 2)

In the techniques of Patent Documents 1 and 2 described above, the tag transmitter continues to transmit the ID without interruption while receiving the trigger signal in the timing area (Patent Document 2 at random intervals). Repeated transmission).
This is because a trigger signal is transmitted by a square loop coil, and it is extremely difficult to detect an accurate trigger point (for example, a time line such as a goal line) in the time measuring area with a tag transmitter. Due to For this reason, the tag transmitter starts transmitting ID as soon as the competitor enters the timing area and detects the trigger signal, and continues to transmit the ID until it exits the timing area and finishes detecting the trigger signal.
On the other hand, when receiving the ID for the first time, the ID receiving unit sets the time as the start time, and when receiving the ID, sets the time as the end time. And the competition time of the player corresponding to this ID was time-measured by calculating | requiring the intermediate | middle time from a start time to an end time.

However, with such techniques of Patent Documents 1 and 2, when a large number of athletes reach the timekeeping area at the same time, the ID receiving unit may not be able to properly receive the ID that should be transmitted. This is because a situation in which the processing on the ID receiving unit side cannot catch up due to a plurality of tag transmitters continuously transmitting IDs to each other in the timing area, or a collision occurs when each ID is transmitted. Because.
For this reason, the start time and end time cannot be obtained correctly in the ID receiving unit, and the inaccurate competition time is timed, or the competition time to be timed is lost with almost no ID reception. There was a problem.
In the technique disclosed in Patent Document 2, the tag transmitter transmits IDs at random intervals to suppress the occurrence of collision. In reality, however, a collision occurred while each tag transmitter repeatedly transmitted an ID within the timing area.

  The present invention has been made in view of the above circumstances, and includes a competition timing system, a wireless device, and a time transmission method that can appropriately measure the competition time of each athlete while suppressing the occurrence of collision. The purpose is to provide.

In order to achieve the above object, a timing system for competition according to the first aspect of the present invention is:
A competition timing system including a plurality of wireless devices carried by each athlete and a receiver for receiving information transmitted from each wireless device on a predetermined channel,
The wireless device includes
A time measuring means for measuring time;
Detection means for detecting a pre-set time point based on the increase or decrease of the electromagnetic field strength of the electromagnetic field generated on the runway;
When the time measuring point is detected by the detecting means, a time specifying means for specifying a time measured by the time measuring means as a time measuring time;
Channel selecting means for selecting one of a plurality of channels according to the time measured by the time specifying means;
In the channel selected by the channel selection means, the presence / absence of transmission from another wireless device to the receiver is determined, and when it is determined that there is no transmission, the timing specified by the time specifying means Wireless communication means for transmitting time information including time to the receiver using the channel, and
The receiver includes
Receiving means for receiving the time information transmitted from the wireless communication means of the wireless device is provided for each channel.
It is characterized by that.

  According to this invention, in the wireless device, the time measuring means, for example, measures the time synchronized with the reference time. The detecting means detects a time point set in advance based on the increase or decrease of the electromagnetic field intensity of the electromagnetic field generated on the runway. The time specifying means specifies the time measured by the time measuring means as the time measured when the time measuring point is detected by the detecting means. The channel selection means selects one channel (for example, one channel out of 10 channels) of the plurality of channels according to the time measured by the time specification means. Then, the wireless communication unit determines whether or not transmission from another wireless device to the receiver is performed on the channel selected by the channel selection unit (that is, whether or not busy), and there is no transmission (that is, busy) Time information including the time measured by the time specifying means is transmitted to the receiver using the channel. On the other hand, in the receiver, the receiving means receives time information from the wireless communication means of the wireless device for each channel.

As described above, the wireless device appropriately waits until wireless communication can be performed while determining busy on the selected channel. When wireless communication is ready, time information is transmitted to the receiver using the channel.
Thus, even when a collision occurs in one transmission, the time information can be transmitted to the receiver without causing a collision in the other transmission.
As a result, it is possible to appropriately time the competition time of each athlete while suppressing the occurrence of collision.

  The channel selection means may select one of the 10 channels according to a value of 1/10 second unit of the time measured.

The wireless device may be provided with transmission control means for transmitting the time information from the wireless communication means over a plurality of times while shifting the transmission timing.
In this case, the plurality of wireless devices are grouped in advance based on, for example, their own identification information (tag ID, etc.), and the transmission control means receives the time information from the wireless communication means. The transmission timing may be shifted for each group.

In order to achieve the above object, a wireless device according to the second aspect of the present invention provides:
A wireless device carried by each competitor,
A time measuring means for measuring time;
Detection means for detecting a pre-set time point based on the increase or decrease of the electromagnetic field strength of the electromagnetic field generated on the runway;
When the time measuring point is detected by the detecting means, a time specifying means for specifying a time measured by the time measuring means as a time measuring time;
Channel selecting means for selecting one of a plurality of channels according to the time measured by the time specifying means;
In the channel selected by the channel selection means, the presence / absence of transmission from another wireless device to a predetermined receiver is determined, and when it is determined that there is no transmission, the time specified by the time specifying means is specified. Wireless communication means for transmitting time information including a time measurement time to the receiver using the channel;
It is characterized by providing.

  According to this invention, the time measuring means measures time synchronized with the reference time, for example. The detecting means detects a time point set in advance based on the increase or decrease of the electromagnetic field intensity of the electromagnetic field generated on the runway. The time specifying means specifies the time measured by the time measuring means as the time measured when the time measuring point is detected by the detecting means. The channel selection means selects one channel (for example, one channel out of 10 channels) of the plurality of channels according to the time measured by the time specification means. Then, the wireless communication unit determines whether or not transmission from another wireless device to the receiver is performed on the channel selected by the channel selection unit (that is, whether or not busy), and there is no transmission (that is, busy) Time information including the time measured by the time specifying means is transmitted to the receiver using the channel.

As described above, the wireless device appropriately waits until wireless communication can be performed while determining busy on the selected channel. When wireless communication is ready, time information is transmitted to the receiver using the channel.
Thus, even when a collision occurs in one transmission, the time information can be transmitted to the receiver without causing a collision in the other transmission.
As a result, it is possible to appropriately time the competition time of each athlete while suppressing the occurrence of collision.

In order to achieve the above object, a time transmission method according to a third aspect of the present invention includes:
A time transmission method in a competition timing system including a plurality of wireless devices carried by each athlete and a receiver that receives information transmitted from each wireless device on a predetermined channel,
In the wireless device, a time measuring step for measuring time;
In the wireless device, based on the increase or decrease of the electromagnetic field strength of the electromagnetic field generated on the runway, a detection step of detecting a pre-installed time point,
In the wireless device, when the time measurement point is detected in the detection step, a time specification step for specifying the time measured in the time measurement step as a time measurement time,
In the wireless device, a channel selection step of selecting one of a plurality of channels according to the time measured specified in the time specification step;
In the wireless device, in the channel selected in the channel selection step, the presence / absence of transmission from another wireless device to the receiver is determined, and when it is determined that there is no transmission, the time specification is performed. Wireless communication step of transmitting time information including the time measured in the step to the receiver using the channel; and
In the receiver, for each channel, a receiving step of receiving time information transmitted from the wireless device in the wireless communication step;
It is characterized by providing.

  According to this invention, in the wireless device, the time measuring step measures time synchronized with the reference time, for example. Moreover, a detection step detects the timing point installed previously based on the increase / decrease in the electromagnetic field intensity | strength of the electromagnetic field produced | generated on the runway. In the time specifying step, the time measured in the time measuring step is specified as the time measuring time when the time measuring point is detected in the detecting step. In the channel selection step, one channel of the plurality of channels (for example, one channel out of 10 channels) is selected according to the time measured in the time specification step. The wireless communication step determines whether or not there is transmission from another wireless device to the receiver (that is, whether or not busy) in the channel selected in the channel selection step, and there is no transmission (that is, busy) Time information including the measured time specified in the time specifying step is transmitted to the receiver using the channel. On the other hand, in the receiver, the reception step receives time information transmitted from the wireless device in the wireless communication step for each channel.

As described above, the wireless device appropriately waits until wireless communication can be performed while determining busy on the selected channel. When wireless communication is ready, time information is transmitted to the receiver using the channel.
Thus, even when a collision occurs in one transmission, the time information can be transmitted to the receiver without causing a collision in the other transmission.
As a result, it is possible to appropriately time the competition time of each athlete while suppressing the occurrence of collision.

  According to the present invention, it is possible to appropriately time the competition time of each player while suppressing the occurrence of collision.

  A game timing system according to an embodiment of the present invention will be described below with reference to the drawings. As an example, a case where the timing system for competition is applied to a marathon competition will be described.

(Embodiment 1)
FIG. 1 is a schematic diagram showing an example of a configuration of a game timing system applied to the embodiment of the present invention.
As shown in the figure, this competition timing system is held by the athlete RN, the signal generation device 10, the loop antenna 20, the receiver 30, and the processing device 40 arranged on and around the runway where the competition is performed. And a wireless tag 50.

  The signal generator 10 is disposed along the road and supplies a signal to the loop antenna 20 to generate an electromagnetic field on the loop antenna 20. Specifically, the signal generator 10 generates an LF (Low Frequency) signal having a predetermined frequency, amplifies it appropriately, and supplies it to the loop antenna 20.

The loop antenna 20 is an antenna (coil) formed in a predetermined shape, and is appropriately arranged on the runway (specifically, the time point defined by the time line L) on which the player RN runs.
As an example, the loop antenna 20 includes a setting antenna unit 21 and a timing antenna unit 22 as shown in FIG.

The setting antenna portion 21 is formed in a substantially rectangular shape (square shape) having a width w, and is arranged so as to cross the running path along the straight lines a and b orthogonal to the running direction (arrow A direction) of the player RN. The feeding point s1 is formed on one side, and a current flows from the feeding point s1 in the direction of the arrow.
On the other hand, the timing antenna unit 22 is formed in a substantially rectangular shape having two widths w, and is arranged so as to cross the running path along the straight lines c and d and the straight lines d and e orthogonal to the running direction. And it forms so that it may have feeding point s2 and s3, and an electric current flows in the direction of an arrow from each feeding point, respectively. Note that the straight line d is arranged so as to overlap with a timing line L for timing.
Further, the setting antenna unit 21 and the timing antenna unit 22 are spaced apart by an interval h.

The loop antenna 20 is configured such that a current flows in the direction of the arrow from each of the feeding points s1 to s3 in FIG. 2A. When an LF signal is supplied from the signal generator 10, each loop antenna 20 Generate an electromagnetic field. Specifically, as shown in FIG. 2B, the electromagnetic field 20a is generated on the setting antenna unit 21, and the electromagnetic fields 20b and 20c are generated on the timing antenna unit 22, respectively.
Note that the interval h separating the setting antenna unit 21 and the timing antenna unit 22 from the electromagnetic field 20a has a small influence on the electromagnetic fields 20b and 20c, and the characteristics of the timing antenna unit 22 are exhibited. It has been obtained in advance by experiments or the like.
Specifically, it is preferable that the setting antenna unit 21 and the timing antenna unit 22 are separated so that the ratio of the length w between the width w and the interval h of each antenna unit is 3: 1. It is clear that an electromagnetic field can be obtained.

  In the electromagnetic field generated on the loop antenna 20 as shown in FIG. 2 (b), the detection direction of the electromagnetic field (direction perpendicular to the detection coil surface D) is perpendicular to the competition track (that is, the detection coil surface D is When an electromagnetic field detection coil C (an LF antenna 51 of a radio tag 50 described later) arranged in a direction parallel to the runway moves in the direction of arrow B, an electromagnetic field intensity distribution as shown in FIG. . That is, since the electromagnetic field detection coil C captures the magnetic flux in the direction perpendicular to the competition track on the coil surface D, the electromagnetic field strength becomes extremely small between the straight lines b and c and on the straight line d. Then, an electromagnetic field intensity distribution as shown in FIG.

Such an electromagnetic field intensity distribution varies to some extent for each loop antenna 20 (signal generator 10).
Therefore, the electromagnetic field 20a generated on the setting antenna unit 21 is used to set a gain (amplification factor) in the amplification circuit 52 of the wireless tag 50 described later. For example, the wireless tag 50 measures (samples) the electromagnetic field intensity of the electromagnetic field 20a for a certain time T, obtains a maximum value, an average value, and the like, and sets an appropriate gain accordingly.
Then, the wireless tag 50 appropriately amplifies the detection signal by the electromagnetic field detection coil C of the electromagnetic fields 20b and 20c generated on the timing antenna unit 22 with the set gain, and the electromagnetic field based on the amplified detection signal. An increase / decrease in the electromagnetic field strength of 20b, 20c is detected, and a timing point is detected based on the increase / decrease in the electromagnetic field strength.

Returning to FIG. 1, the receiver 30 is arranged in the vicinity of the loop antenna 20 described above, and receives the competition time and the tag ID sent from the wireless tag 50 that has passed over the loop antenna 20.
Specifically, the receiver 30 receives a competition time or the like transmitted from the wireless tag 50 at any frequency (any channel) among a plurality of predefined frequencies (for example, 10 channels). . Then, the received competition time and the like are supplied to the processing device 40.

The processing device 40 is composed of a personal computer or the like, and collects the competition time counted by each wireless tag 50.
In other words, when the processing device 40 receives the competition time and the tag ID transmitted from each wireless tag 50 that has passed over the loop antenna 20 via the receiver 30, the processing device 40 stores them in a predetermined storage unit.

  On the other hand, the wireless tag 50 held by the player RN moves on the track together with the player RN. When the wireless tag 50 first detects an electromagnetic field generated by the loop antenna 20 (setting antenna unit 21), the wireless tag 50 sets an appropriate gain from the measured electromagnetic field strength. When the inflection point of the electromagnetic field generated by the loop antenna 20 (clocking antenna unit 22) is detected after setting the gain, the time measured at that timing is specified as the competition time.

  As an example, the wireless tag 50 includes an LF antenna 51, an amplifier circuit 52, a detection circuit 53 as a detection unit, a time specifying unit, a channel selection unit, a control unit 54 as a transmission control unit, and a timing unit. The timer unit 55 is configured to include a storage unit 56, a communication circuit 57 as a wireless communication unit, and a communication antenna 58.

The LF antenna 51 is set so that the detection direction of the electromagnetic field is perpendicular to the competition track (that is, the detection surface is parallel to the track), and detects the electromagnetic field generated by the loop antenna 20 described above. . That is, the electromagnetic field generated on the setting antenna unit 21 and the timing antenna unit 22 by the signal generator 10 is detected.
Then, the LF antenna 51 supplies a detection signal indicating the detected electromagnetic field strength of the electromagnetic field to the amplifier circuit 52.

The amplifier circuit 52 appropriately amplifies the detection signal supplied from the LF antenna 51 and supplies the amplified detection signal to the detection circuit 53.
For example, the amplification circuit 52 can perform automatic gain control (AGC), and when an electromagnetic field generated by the loop antenna 20 (setting antenna unit 21) is first detected, an appropriate gain is obtained from the measured electromagnetic field strength. Set.
Specifically, the amplification circuit 52 measures the electromagnetic field intensity of the electromagnetic field 20a generated by the setting antenna unit 21 for a certain time T, obtains the maximum value, the average value, etc., and sets an appropriate gain according to them. To do. Then, after setting the gain, the detection signals of the electromagnetic fields 20b and 20c generated by the timing antenna unit 22 are amplified.
The amplifier circuit 52 clears the gain setting value in response to an instruction from the control unit 54 in order to reset the gain for each loop antenna 20 (for each time point).

The detection circuit 53 detects an inflection point (trigger point) of the electromagnetic field on the timing antenna unit 22 based on the detection signal (electromagnetic field strength) supplied from the amplification circuit 52.
That is, the trigger point (that is, the time measuring point) is detected based on the increase / decrease of the electromagnetic field intensity of the electromagnetic field supplied from the amplification circuit 52 in which the gain is set.
Specifically, the detection circuit 53 generates a signal having a waveform as shown in FIG. 3B for the electromagnetic fields 20a to 20c on the loop antenna 20 as shown in FIG. Since the waveform corresponding to the electromagnetic field 20a is used for setting the gain of the amplifier circuit 52, the rising after the start of the waveform detection shown in FIG. 3B, that is, the electromagnetic field 20b on the timing antenna unit 22 is obtained. , 20c is specified as a time point (time line L).

Returning to FIG. 1, the control unit 54 controls the entire wireless tag 50.
In the control unit 54, the timing unit 55 counts the timing when the amplification circuit 52 sets the gain and the detection circuit 53 detects the inflection point of the electromagnetic field (the inflection point of the electromagnetic fields 20b and 20c) on the timing antenna unit 22. Specify time as competition time. Then, the specified competition time is stored in the storage unit 56.

Moreover, the control part 54 selects the frequency used for transmission from the specified competition time. Specifically, the control unit 54 selects one of the 10 channels (channel 1 to channel 10) according to the value (0 to 9) in units of 1/10 seconds in the competition time.
That is, when a plurality of wireless tags 50 reach the timing point at the same time in a group, the channels to be used for transmission are divided according to the value of 1/10 second unit of the measured competition time. .
Specifically, in the case of a marathon, the wireless tag 50 (competitor RN) moves about 50 cm in 1/10 second. Therefore, as shown in FIG. 4, for example, in the range of 1 second (about 5 m), one different channel (channel 1 to channel 10) is assigned to every 1/10 second unit (about 50 cm unit). become. Each wireless tag 50 uses the same channel only within 1/10 second (about 50 cm area). That is, the channels used for transmission are assigned to different channels in units of 1/10 seconds, and the number assigned to the same channel is limited.
More specifically, in a marathon, within the range of 1/10 second (about 50 cm), depending on the track width, a maximum of approximately 6 athletes RN can pass through the normal track width, The number assigned is limited to about six at most.
In addition, after 1 second has passed, each channel is sequentially assigned to each subsequent wireless tag 50 in the same manner, but each wireless tag 50 of the preceding same channel has been (until 9/10 seconds) until then. B) Since communication is completed, communication is not performed at the same time on the same channel.

In this way, when one channel is selected according to the value of 1/10 second unit in the competition time, the control unit 54 controls the communication circuit 57 to store the competition time and tag ID (stored in the storage unit 56). The self tag ID) is transmitted to the receiver 30 using the channel.
At this time, the control unit 54 determines whether or not another wireless tag 50 in the same channel (other wireless tag 50 using the same channel) is transmitting (busy) and is in a state where wireless communication can be performed. Wait as appropriate until When the wireless communication is ready, the competition time and the like are transmitted to the receiver 30.
Note that if such a competition time or the like is transmitted only once, depending on the timing, it may overlap with the transmission in the other wireless tag 50 on the same channel, and there is a possibility that collision will occur. Moreover, even if transmission can be performed without causing a collision, rarely data corruption (parity error, etc.) such as competition time may occur.
As a countermeasure against such collision and data corruption, the control unit 54 causes the communication circuit 57 to transmit the same competition time and the like over a plurality of times.

  Hereinafter, the wireless communication controlled by the control unit 54 will be specifically described with reference to FIG. As a countermeasure against collision and data corruption, the control unit 54 causes the communication circuit 57 to perform the same transmission multiple times (N times) within 9/10 seconds.

First, as a simplest example, a case where transmission is performed twice or more in a state where no busy state is generated will be described with reference to FIG.
First, when the competition time is specified, the control unit 54 causes the communication circuit 57 to perform carrier sense (in the same channel) at timing T1. When performing carrier sense, the communication circuit 57 is in a reception mode.

If it is determined that the communication is not in progress, the control unit 54 waits for the data processing time γ.
This data processing time γ is a time required for the receiver 30 to supply (transfer) the received data (competition time, etc.) to the processing device 40, and during this time, the receiver 30 receives wireless data from the wireless tag 50. The transmission cannot be received (that is, the wireless non-reception period is reached). Therefore, in order to avoid this wireless non-reception period, the control unit 54 waits for the data processing time γ.

When the standby of the data processing time γ is finished, the control unit 54 causes the communication circuit 57 to perform carrier sense at timing T2, and when it is determined that the communication is not busy, the control unit 54 waits for the monitoring time (carrier sense monitoring time) β.
This monitoring time β is equivalent to the time required for the communication circuit 57 to switch from the reception mode to the transmission mode (reception / transmission switching time). That is, it takes only time β (reception transmission switching time β) until the wireless tag 50 after carrier sense actually starts transmission, and during this time, it is determined that the other wireless tag 50 is not busy and performs transmission. Since something (or what has already been done) may occur, the control unit 54 waits for the monitoring time β.

When waiting for the monitoring time β is completed, the control unit 54 causes the communication circuit 57 to perform carrier sense again at timing T3, and when determining that the communication circuit 57 is not busy, switches the communication circuit 57 from the reception mode to the transmission mode.
As described above, the communication circuit 57 requires time β (reception transmission switching time β) to switch to the transmission mode (reception / transmission switching).

When the reception / transmission switching is completed, the control unit 54 transmits the competition time and the like from the communication circuit 57 at the timing T4.
The communication circuit 57 requires the communication time α for this transmission.

In this way, when the first transmission is completed, the control unit 54 waits for a series of processing times τ from the timing T5.
The series processing time τ is a time obtained by adding the above-described data processing time γ, monitoring time β, reception / transmission switching time β, and communication time α. By waiting for this series of processing times τ, the other wireless tag 50 is given an opportunity to perform similar wireless communication.
Note that the control unit 54 switches the communication circuit 57 from the transmission mode to the reception mode using this interval.

  When the standby for the series of processing times τ is completed, the control unit 54 causes the communication circuit 57 to perform carrier sense at timing T6, and when it is determined that it is not busy, it waits for the data processing time γ.

When waiting for the data processing time γ is completed, the control unit 54 causes the communication circuit 57 to perform carrier sense at timing T7, and if it is determined that it is not busy, it waits for the group time χ.
This group time χ is a time that differs in advance for each group to which each wireless tag 50 belongs. Specifically, according to the group, the time β is an integral multiple (for example, 1 time, 2 times, 3 times,.・ ・) It is the time of the minute.
Note that the wireless tags 50 are grouped in advance based on, for example, tag ID values (bit values, etc.). That is, each wireless tag 50 has a different group time χ defined according to the group to which the wireless tag 50 belongs.

When waiting for the group time χ ends, the control unit 54 causes the communication circuit 57 to perform carrier sense again at timing T8, and when determining that the communication circuit 57 is not busy, switches the communication circuit 57 from the reception mode to the transmission mode.
When the reception / transmission switching is completed, the control unit 54 transmits the competition time and the like from the communication circuit 57 at timing T9. That is, the second transmission is performed.

In this way, when the second transmission is completed, the control unit 54 waits for the series processing time τ from the timing T10, and then performs the third transmission. The third transmission is the same as the second transmission.
That is, the control unit 54 waits for the data processing time γ when it is determined that it is not busy at the timing T11, and waits for the group time χ when it is determined that it is not busy at the timing T12. If it is determined at time T13 that the communication circuit 57 is not busy, the communication circuit 57 is switched from the reception mode to the transmission mode, and the competition time is transmitted from the communication circuit 57 at time T13.

In the first transmission and the second and subsequent transmissions performed in this way, whether to wait for the monitoring time β after waiting for the data processing time γ (timing T2) or whether to wait for the group time χ (timing) T7, T12) are different.
Even if a collision occurs in the first transmission (overlaps with the transmission of another wireless tag 50 in the same channel), the second time transmission has a different group time χ ( This is to prevent the occurrence of collision by shifting the transmission timing by an integral multiple of time β.

Note that the transmission timing is originally shifted by an integral multiple of the time β, and collision may occur by shifting the transmission timing by an integral multiple of the time β in the second transmission. Still, in that case, the collision is not generated in the first transmission, and the transmission is effectively completed. Further, even if a collision with another wireless tag 50 occurs in the first transmission, the transmission can be performed in the third transmission.
In addition, the larger the number of groups, the smaller the probability of collision occurrence, so it may be possible to increase the number of groups. However, the adverse effect is that the processing time per unit processing time can be increased by increasing the group time χ. Number will decrease.
Therefore, the number of groups is appropriately determined in consideration of the number of RFID tags 50 that must be processed at the same time (the number of competitors RN expected to reach the timing point at the same time), etc. Yes.

Next, a case where a busy state occurs during communication will be described with reference to FIGS.
FIG. 5B shows an example in which a busy state occurs at timing T21. This timing T21 corresponds to the timing T1 (T6, T11) shown in FIG.
FIG. 5C shows an example in which a busy state occurs at timing T33. This timing T33 corresponds to the timing T3 (T8, T13) shown in FIG.

First, as shown in FIG. 5B, at timing T21, when the communication circuit 57 performs carrier sense (in the same channel) and determines that it is busy, the control unit 54 waits for the communication time α. To do. That is, it waits for the busy transmission to end.
When the standby for the communication time α is completed, the control unit 54 causes the communication circuit 57 to perform carrier sense at timing T22. When the control unit 54 determines that it is not busy, the control unit 54 waits for the data processing time γ. That is, the wireless non-reception period of the receiver 30 is avoided.

When waiting for the data processing time γ is completed, the control unit 54 causes the communication circuit 57 to perform carrier sense at timing T23 and determines that the communication circuit 57 is not busy. ) Just wait.
When waiting for the monitoring time β (or group time χ) is completed, the control unit 54 causes the communication circuit 57 to perform carrier sense again at timing T24. Switch to transmission mode from.
When the reception / transmission switching is completed, the control unit 54 transmits the competition time and the like from the communication circuit 57 at the timing T25.

On the other hand, as shown in FIG. 5 (c), when it is determined that the communication is in progress at the timing T33 after waiting for the data processing time γ and the monitoring time β (the group time χ if it is the second time or more), Similarly, the control unit 54 waits for the communication time α.
Thereafter, assuming that the busy state does not occur, similarly to the above, the control unit 54 finishes waiting for the data processing time γ and the monitoring time β (or the group time χ for the second time or more), and then the communication circuit 57. The reception / transmission switching is performed, and the competition time and the like are transmitted from the communication circuit 57 at timing T37.

  As described above, the control unit 54 determines whether the communication circuit 57 is busy on the same channel and appropriately waits until wireless communication can be performed. When the wireless communication can be performed, the transmission timing is appropriately shifted between the first time and the second time or more, and the competition time and the like are transmitted from the communication circuit 57 to the receiver 30.

Returning to FIG. 1, the timing unit 55 appropriately corrects (sets) the control unit 54 and counts the time synchronized with the reference time that is the reference in the competition.
Note that the timekeeping unit 55 includes a highly stable crystal oscillator, and can keep time keeping stable.

The storage unit 56 includes, for example, a non-volatile memory, and stores the competition time and the like specified by the control unit 54.
The storage unit 56 is provided with, for example, storage areas for time points of competitions, and the competition times measured at the respective time points can be stored in different storage areas.
In addition, the memory | storage part 56 has memorize | stored beforehand the specific identification information (tag ID) etc. which differ for every radio | wireless tag 50 (every player RN) etc. in the separate area, for example. As described above, this tag ID is used for grouping to determine the group time χ.

The communication circuit 57 is controlled by the control unit 54 and transmits the competition time and the like to the receiver 30 using the selected channel. Specifically, the communication circuit 57 determines whether another wireless tag 50 is transmitting on the same channel by carrier sense via the communication antenna 58, and supplies the determination result to the control unit 54. When wireless communication can be performed on the channel, the competition time and the like are transmitted to the receiver 30 via the communication antenna 58 based on the control of the control unit 54.
In addition, the communication circuit 57 transmits the same competition time etc. several times as a countermeasure against a collision or garbled data. At that time, based on the control of the control unit 54, transmission is performed by appropriately shifting the transmission timing between the first time and the second time or more.
The communication antenna 58 is an antenna used for communication.

  Hereinafter, the operation of the wireless tag 50 in the competition timing system having the above-described configuration will be described with reference to FIG. FIG. 6 is a flowchart for explaining time transmission processing executed by the wireless tag 50. This time transmission process is started, for example, when the wireless tag 50 moving with the player RN detects an electromagnetic field on the loop coil 20.

  First, the wireless tag 50 waits until it detects a trigger point (timekeeping point) (step S11). That is, as shown in FIG. 3B described above, after the detection circuit 53 finishes setting the gain of the amplifier circuit 52, the rising edge after the start of detection is specified, and the inflection point of the electromagnetic field on the timing antenna unit 22 is determined. The execution of the subsequent processing is waited until a time point that becomes (the inflection point of the electromagnetic fields 20b and 20c) is detected.

  When the trigger point is detected, the wireless tag 50 specifies the competition time (step S12). That is, the control unit 54 specifies the time measured by the time measuring unit 55 as the competition time at the timing when the inflection point of the electromagnetic field on the time measuring antenna unit 22 is detected. Then, the specified competition time is stored in the storage unit 56.

  The wireless tag 50 selects a channel to be used for transmission from the identified competition time (step S13). That is, the control unit 54 selects one of the 10 channels according to the value of 1/10 second unit in the competition time.

  The wireless tag 50 determines whether or not the selected channel is busy (step S14). That is, the wireless tag 50 causes the communication circuit 57 to perform carrier sense, and determines whether another wireless tag 50 is transmitting on the same channel.

  If it is determined that the wireless tag 50 is busy, the wireless tag 50 waits for the communication time α (step S15). That is, it waits for the busy transmission to end. Then, the process returns to step S14 described above.

On the other hand, if it is determined in step S14 that the communication is not in progress, the wireless tag 50 waits for the data processing time γ (step S16). That is, the wireless non-reception period of the receiver 30 is avoided.
Then, the wireless tag 50 determines whether or not it is busy (step S17). If it is determined that the communication is in progress, the process returns to step S15 described above. If it is determined that it is not busy, the wireless tag 50 determines whether or not it has been transmitted once (step S18). That is, it is determined whether the first transmission will be performed from now on, and whether the second transmission or more will be performed from now on.

If it is determined that the wireless tag 50 has not been transmitted once (the first transmission will be performed from now on), the wireless tag 50 waits for the monitoring time β (step S19). On the other hand, if it is determined that the transmission has been completed once (from now on, transmission is performed for the second time or more), the system waits for the group time χ (step S20).
That is, in the case of the first transmission, since it is not known which wireless tag 50 (the other wireless tag 50) overlaps, the wireless tag 50 waits for the monitoring time β as it is. Further, in the case of the second transmission or more, in consideration of the case where a collision occurs in the first transmission or the like, the transmission timing is shifted to wait for a different group time χ (integer multiple of time β) for each group.

  When the standby for the monitoring time β or the group time χ is finished, the wireless tag 50 determines whether or not it is busy (step S21). If it is determined that the communication is in progress, the process returns to step S15 described above. If the wireless tag 50 is determined not to be busy, the wireless tag 50 performs reception / transmission switching (step S22). That is, the communication circuit 57 is switched from the reception mode to the transmission mode.

  When the reception / transmission switching is completed, the wireless tag 50 transmits the competition time and the like to the receiver 30 (step S23). That is, the competition time and the tag ID are transmitted from the communication circuit 57.

  When the transmission is finished, the wireless tag 50 determines whether or not the transmission has been performed N times (step S24). That is, it is determined whether or not a predetermined N-th transmission has been completed by the current transmission.

If it is determined that the wireless tag 50 has not been transmitted N times (the Nth transmission has not been completed), the wireless tag 50 waits for a series of processing times τ (step S25). That is, after waiting for a series of processing times τ (processing time γ + monitoring time β + reception / transmission switching time β + communication time α), another wireless tag 50 has an opportunity to perform similar wireless communication on the same channel.
When the standby for the series of processing times τ ends, the wireless tag 50 returns the process to the above-described step S14 in order to perform the second or more transmission.

  If it is determined in step S24 that the transmission has been performed N times (the Nth transmission has been completed), the wireless tag 50 ends the time transmission process.

By such a time transmission process, the wireless tag 50 appropriately waits until wireless communication is possible while determining busy on the selected channel. When the wireless communication is ready, the transmission timing is appropriately shifted between the first time and the second time or more, and the competition time and the like are transmitted to the receiver 30.
Thereby, even when a collision occurs in one transmission, the competition time or the like can be transmitted to the receiver 30 without causing a collision in the other transmission. Further, by transmitting the same competition time etc. multiple times, it is possible to cope with data corruption (parity error, etc.).
As a result, it is possible to appropriately time the competition time of each athlete while suppressing the occurrence of collision.

Next, with reference to FIG. 7, the operation of the competition timing system as a whole will be described. FIG. 7 is a schematic diagram for explaining a state of transmission in each wireless tag 50 and reception in the receiver 30 (processing device 40).
As an example, transmission / reception of channel 1 will be described, but similar transmission / reception is performed in other channels (channels 2 to 10).

First, the tags A and B that specify the competition time determine whether or not they are talking at timings T11 and T21. In this case, the tags A and B wait for the data processing time γ and the monitoring time β because they are not busy. Then, since it is not busy after that, after switching to the transmission mode, the first transmission is performed at timings T12 and T22.
These transmissions collide with each other (collision occurs).

Similarly, the tag C that specified the competition time determines whether or not it is busy at timing T31. In this case, since it is not busy, the tag C waits for the data processing time γ and the monitoring time β. After that, at timing T32, it is determined that talking is in progress (tags A and B are being transmitted), and tag C waits for communication time α, data processing time γ, and monitoring time β.
The tag D specifying the competition time is determined to be busy (tags A and B are transmitting) at timing T41, and waits for a communication time α, a data processing time γ, and a monitoring time β.
Since the tags C and D that have finished waiting for the monitoring time β are not busy after that, the first transmission is performed at timings T33 and T42 after switching to the transmission mode.
These transmissions collide with each other (collision occurs).

The tags A and B that have completed the first transmission (collision) at the timings T12 and T22 wait for a series of processing times τ, and determine whether or not they are busy at the timings T13 and T23. In this case, since it is busy (tags C and D are transmitting), the tags A and B wait for the communication time α, the data processing time γ, and the group time χ.
Since the tags A and B have different groups, the group times χ are also different.

  Since the tag A that has finished waiting for the group time χ is not busy thereafter, the tag A is switched to the transmission mode and then transmitted at the timing T14 for the second time. Although omitted in the figure, the tag A repeats the same transmission process until the Nth transmission.

The tag B that has finished waiting for the group time χ is determined to be busy (tag A is transmitting) at timing T24, and waits for the communication time α, the data processing time γ, and the group time χ.
Since it is not busy this time, the tag B performs the second transmission at timing T25 after switching to the transmission mode. Although omitted in the figure, tag B repeats the same transmission process until the Nth transmission.

  The tags C and D that have completed the first transmission (collision) at the timings T33 and T42 wait for a series of processing times τ, and determine whether or not they are busy at the timings T34 and T43. In this case, since it is busy (the tag A is transmitting), the tags C and D wait for the communication time α, the data processing time γ, and the group time χ. Since the tags C and D have different groups, the group times χ are also different.

  The tags C and D that have finished waiting for the group time χ are determined to be busy (tag B is transmitting) at timings T35 and T44, and further, the communication time α, data processing time γ, group time χ and standby To do.

  Since the tag C that has finished waiting for the group time χ is not busy thereafter, the tag C is switched to the transmission mode, and then the second transmission is performed at timing T36. Although omitted in the figure, the tag C repeats the same transmission process until the Nth transmission.

The tag D that has finished waiting for the group time χ is determined to be busy (the tag C is transmitting) at timing T45, and further waits for the communication time α, the data processing time γ, and the group time χ.
Then, since it is not busy this time, the tag D performs the second transmission at timing T46 after switching to the transmission mode. The tag D repeats the same transmission process until the Nth transmission is performed.

In this way, the tags A to D (each wireless tag 50) that have selected the channel 1 appropriately wait until the wireless communication can be performed while determining that the channel 1 is busy. When wireless communication can be performed, transmission is performed by appropriately shifting the transmission timing between the first time and the second time or more.
Thereby, for example, even when both transmissions collide (collision occurs) during the first transmission of the tags A and B, the group time χ differs between the tag A and the tag B. The transmission timing is different at the second transmission of both, and the competition time and the like can be transmitted to the receiver 30 without colliding with both transmissions.
As a result, it is possible to appropriately time the competition time of each athlete while suppressing the occurrence of collision.

(Other embodiments)
In the above-described embodiment, the case where one receiver 30 receives transmissions from all the wireless tags 50 using each channel has been described. However, a plurality of receivers 30 can receive from each wireless tag 50 for each channel. You may make it receive the competition time etc. which are transmitted.
For example, ten receivers 30 may be arranged so that each receiver 30 receives a transmission of a different channel.

In the above-described embodiment, the case where the competition time or the like is unilaterally transmitted from the wireless tag 50 side has been described. However, an arbitrary wireless tag 50 may be designated by polling to be transmitted.
For example, when the player RN passes the time line L and the transmission from the wireless tag 50 cannot be received even after a predetermined time has elapsed (for example, even after 5 seconds have elapsed), the A tag ID is transmitted toward the wireless tag 50.
In other words, when the competition time or the like cannot be received by the receiver 30 and 5 seconds have elapsed, the processing device 40 transmits a tag ID from a predetermined transmitter, designates the wireless tag 50, and transmits it. Make a request.
Then, the designated wireless tag 50 transmits the competition time and the like toward the receiver 30.
As described above, by further performing polling reception, it is possible to prevent the transmission from the wireless tag 50 from being missed.

In the above embodiment, the marathon competition has been described as an example, but the competition to be timed is not limited to this and is arbitrary.
For example, the present invention can be applied as appropriate to relay races, racewalking, disabled wheelchair road races, bicycle road races, triathlons, and mountain sports such as running and orientation.

  As described above, according to the present invention, it is possible to appropriately time the competition time of each player while suppressing the occurrence of collision.

It is a schematic diagram which shows an example of a structure of the timing system for competitions concerning embodiment of this invention. (A) is a schematic diagram which shows an example of the loop antenna arrange | positioned on a runway, (b) is a schematic diagram for demonstrating the direction of the electromagnetic field and magnetic field detection coil which are produced | generated, (c) is detected It is a schematic diagram for demonstrating intensity distribution of the electromagnetic field to be performed. (A) is a schematic diagram which shows an example of the electromagnetic field produced | generated on an antenna, (b) is a schematic diagram for demonstrating the detection waveform produced | generated by a detection circuit. It is a schematic diagram for demonstrating the relationship between an area and a channel. (A)-(c) is a schematic diagram for demonstrating the specific mode of radio | wireless communication. It is a flowchart for demonstrating the time transmission process which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the mode of transmission of each wireless tag in one channel, and reception of a receiver (processing apparatus).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Signal generator 20 Loop antenna 30 Receiver 40 Processing apparatus 50 Wireless tag

Claims (6)

A competition timing system including a plurality of wireless devices carried by each athlete and a receiver for receiving information transmitted from each wireless device on a predetermined channel,
The wireless device includes
A time measuring means for measuring time;
Detection means for detecting a pre-set time point based on the increase or decrease of the electromagnetic field strength of the electromagnetic field generated on the runway;
When the time measuring point is detected by the detecting means, a time specifying means for specifying a time measured by the time measuring means as a time measuring time;
Channel selecting means for selecting one of a plurality of channels according to the time measured by the time specifying means;
In the channel selected by the channel selection means, the presence / absence of transmission from another wireless device to the receiver is determined, and when it is determined that there is no transmission, the timing specified by the time specifying means Wireless communication means for transmitting time information including time to the receiver using the channel, and
The receiver includes
Receiving means for receiving the time information transmitted from the wireless communication means of the wireless device is provided for each channel.
A timekeeping system for competitions. The channel selection means selects one of 10 channels according to a value of 1/10 second unit of the timekeeping time;
The competition timekeeping system according to claim 1, wherein: The wireless device is provided with transmission control means for transmitting the time information from the wireless communication means over a plurality of times while shifting the transmission timing.
The timing system for competition according to claim 1 or 2, wherein The plurality of wireless devices are grouped in advance,
The transmission control means causes the wireless communication means to transmit the time information with a transmission timing shifted for each group.
The game timekeeping system according to claim 3. A wireless device carried by each competitor,
A time measuring means for measuring time;
Detection means for detecting a pre-set time point based on the increase or decrease of the electromagnetic field strength of the electromagnetic field generated on the runway;
When the time measuring point is detected by the detecting means, a time specifying means for specifying a time measured by the time measuring means as a time measuring time;
Channel selecting means for selecting one of a plurality of channels according to the time measured by the time specifying means;
In the channel selected by the channel selection means, the presence / absence of transmission from another wireless device to a predetermined receiver is determined, and when it is determined that there is no transmission, the time specified by the time specifying means is specified. Wireless communication means for transmitting time information including a time measurement time to the receiver using the channel;
A wireless device comprising: A time transmission method in a competition timing system including a plurality of wireless devices carried by each athlete and a receiver that receives information transmitted from each wireless device on a predetermined channel,
In the wireless device, a time measuring step for measuring time;
In the wireless device, based on the increase or decrease of the electromagnetic field strength of the electromagnetic field generated on the runway, a detection step of detecting a pre-installed time point,
In the wireless device, when the time measurement point is detected in the detection step, a time specification step for specifying the time measured in the time measurement step as a time measurement time,
In the wireless device, a channel selection step of selecting one of a plurality of channels according to the time measured specified in the time specification step;
In the wireless device, in the channel selected in the channel selection step, the presence / absence of transmission from another wireless device to the receiver is determined, and when it is determined that there is no transmission, the time specification is performed. Wireless communication step of transmitting time information including the time measured in the step to the receiver using the channel; and
In the receiver, for each channel, a receiving step of receiving time information transmitted from the wireless device in the wireless communication step;
A time transmission method comprising:

Images