JP2007256059A - Radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication device dispensing with synchronization processing, and having a small power consumption. <P>SOLUTION: This device is equipped with the first wireless apparatus 1 and the second wireless apparatus 2 communicating by radio mutually. The first wireless apparatus 1 includes a transmission circuit 3 for transmitting a distance measuring signal, and outputting a transmission timing signal at a transmission timing of the distance measuring signal; a reception circuit 5 for receiving a return signal, and outputting a reception timing signal at a reception timing of the return signal; a delay time measuring circuit 7 for measuring a time difference of the reception timing signal to the transmission timing signal as a delay time; and a distance operation circuit 8 for operating the distance between first wireless apparatus 1 and the second wireless apparatus 2. The delay time measuring circuit 7 has a plurality of delay circuits D1-Dn connected in parallel and having each different delay characteristic, and measures the delay time by using a delayed transmission timing signal acquired by delaying the transmission timing signal through the plurality of delay circuits D1-Dn and the reception timing signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless communication device that calculates a distance between a first wireless device and a second wireless device that communicate with each other wirelessly.

The conventional distance detection apparatus includes a transmission unit, a reception unit, a signal input unit, and a distance detection unit.
The transmission means generates a periodic signal using its own reference timer (reference clock) and transmits it to the partner station. The receiving means receives a signal transmitted from the partner station to the station by generating a periodic signal using the reference timer of the partner station. The signal input means inputs the transmission signal from the transmission means directly to the reception means.
The distance detection means measures the difference between the transmission timing when the signal is transmitted from the transmission means and the reception timing when the transmission signal is input to the reception means by the signal input means to determine the local signal delay time, Further, the reception timing at which the transmission signal from the partner station is received is measured by measuring the amount of deviation from the reference timing of the reference timer of the own station to determine the own station detection phase difference. The relative distance between the local station and the partner station is detected using the partner station signal delay time and the partner station detection phase difference obtained by the partner station (see, for example, Patent Document 1).

In the conventional apparatus, the delay time is measured using the reference timer (reference clock) of the local station and the partner station. The period of the reference timer is generated by an oscillation component such as a crystal oscillator or a crystal resonator.
However, since these oscillation components have individual differences in the accuracy of the generation cycle, a deviation occurs between the reference timer of the local station and the reference timer of the counterpart station as time elapses.
Therefore, in order to ensure sufficient distance measurement accuracy, it is necessary to perform synchronization processing that periodically matches the timings of the reference timer of the local station and the reference timer of the partner station.

In addition, in a network system using a short-range wireless technology such as a wireless sensor node having a communication distance of about several tens of meters, it is assumed that the installation interval of each device is as short as about 5 m.
For example, when the distance measurement accuracy is 1 m, the radio wave propagation delay time is about 3.3 ns per meter.
Therefore, when the delay time is measured using the reference timer as in the above-described conventional apparatus, a reference timer that operates at a high frequency is required to ensure sufficient distance measurement accuracy.

JP 2001-33543 A

In conventional distance detectors, as time elapses, a deviation occurs between the reference timer of the local station and the reference timer of the partner station. Therefore, in order to ensure sufficient distance measurement accuracy, frequent synchronization processing is executed. Therefore, there is a problem that the distance measurement processing is hindered.
In addition, in a network system that applies short-range wireless technology, a reference timer that operates at a high frequency is required to ensure sufficient distance measurement accuracy, which increases power consumption.

  An object of the present invention is to provide a wireless communication apparatus that does not require synchronization processing and consumes less power.

  A wireless communication apparatus according to the present invention includes a first wireless device and a second wireless device that wirelessly communicate with each other, and the first wireless device transmits a transmission signal to the second wireless device and transmits the transmission signal. A transmission means for outputting a transmission timing signal at a timing; a reception means for receiving a reception signal in which the transmission signal is returned by the second radio; and a reception timing signal at the reception timing of the reception signal; a transmission timing signal; In response to the reception timing signal, a delay time measuring unit that measures a time difference between the reception timing signal and the transmission timing signal as a delay time, and calculates a distance between the first radio and the second radio based on the delay time The delay time measuring means includes a plurality of delay elements that are connected in parallel and have different delay characteristics from each other, and are capable of reproducing transmission timing signals. A delayed transmission timing signal is delayed through a delay element, and measures the delay time by using the reception timing signal.

According to the radio communication apparatus of the present invention, the delay time measuring means includes a plurality of delay elements connected in parallel and having different delay characteristics, and delay transmission timing obtained by delaying the transmission timing signal via the plurality of delay elements. The delay time is measured using the signal and the reception timing signal.
Therefore, it is not necessary to use a reference timer, the synchronization process can be made unnecessary, and the power consumption can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a wireless communication apparatus according to Embodiment 1 of the present invention.
In FIG. 1, the wireless communication apparatus includes a first wireless device 1 and a second wireless device 2.
The first radio 1 includes a transmission circuit (transmission means) 3, a transmission antenna 4, a reception circuit (reception means) 5, a reception antenna 6, a delay time measurement circuit (delay time measurement means) 7, and a distance calculation. And a circuit (distance calculation means) 8.
The second radio 2 includes a reception circuit 9, a reception antenna 10, a folding circuit (folding means) 11, a transmission circuit 12, and a transmission antenna 13.

Here, the transmission circuit 3, the reception circuit 5, the reception circuit 9, the folding circuit 11, and the transmission circuit 12 are configured using analog circuits without using a reference timer (reference clock).
The transmission circuit 3, the reception circuit 5, and the delay time measurement circuit 7 operate under the control of a first control unit (not shown) provided in the first wireless device 1. In addition, the reception circuit 9, the folding circuit 11, and the transmission circuit 12 operate under the control of a second control unit (not shown) provided in the second wireless device 2.

  The distance calculation circuit 8, the first control unit, and the second control unit are configured by a microprocessor (not shown) having a CPU and a storage unit that stores a program.

  The transmission circuit 3 transmits a distance measurement signal (transmission signal) to the second radio 2 via the transmission antenna 4 and outputs a transmission timing signal to the delay time measurement circuit 7 at the transmission timing of the distance measurement signal. To do.

  The reception circuit 5 receives the return signal (reception signal) obtained by returning the distance measurement signal from the second radio device 2 via the reception antenna 6, and receives the reception timing to the delay time measurement circuit 7 at the reception timing of the return signal. Output a signal.

In response to the transmission timing signal from the transmission circuit 3 and the reception timing signal from the reception circuit 5, the delay time measurement circuit 7 measures the time difference between the reception timing signal and the transmission timing signal as a delay time.
The distance calculation circuit 8 calculates the distance between the first radio device 1 and the second radio device 2 based on the delay time measured by the delay time measurement circuit 7.

The receiving circuit 9 receives the distance measurement signal from the first radio device 1 via the receiving antenna 10 and outputs it to the folding circuit 11.
The loopback circuit 11 receives the distance measurement signal from the reception circuit 9 and outputs it to the transmission circuit 12 as a loopback signal after an arbitrarily set loopback time.
The transmission circuit 12 transmits the return signal from the return circuit 11 to the first radio device 1 via the transmission antenna 13.

  Here, a delay accompanying transmission in the transmission circuit 3 is defined as a delay time T1. Further, the time required for propagation of the distance measurement signal from the transmission antenna 4 to the reception antenna 10 is defined as a propagation time T2. A delay associated with reception by the receiving circuit 5 is defined as a delay time T3. Further, the time required for the return in the return circuit 11 is defined as a return time T4. A delay associated with transmission in the transmission circuit 12 is defined as a delay time T5. Further, the time required for propagation of the folded signal from the transmitting antenna 13 to the receiving antenna 6 is defined as a propagation time T2 as described above. A delay associated with reception by the receiving circuit 5 is defined as a delay time T6.

  That is, assuming that the delay time, propagation time, and return time taken from the transmission of the distance measurement signal by the transmission circuit 3 to the reception of the return signal by the reception circuit 5 are the total delay time Tt, the total delay time Tt is expressed by the following equation (1) ).

  Tt = T1 + T2 × 2 + T3 + T4 + T5 + T6 (1)

In equation (1), delay times T1, T3, T5, T6 and turnaround time T4 are values known as device specifications.
That is, as described above, since the transmission circuit 3, the reception circuit 5, the reception circuit 9, the folding circuit 11, and the transmission circuit 12 are configured using analog circuits, the delay times T1, T3, T5, T6 and The turnaround time T4 can be handled as a fixed value that is not affected by the reference timer (clock).

FIG. 2 is a block diagram showing in detail the delay time measuring circuit 7 of FIG.
In FIG. 2, the delay time measuring circuit 7 includes n delay circuits (delay elements) D1 to Dn connected in parallel, and n latch circuits L1 to Ln connected to the delay circuits D1 to Dn, respectively. have.

The delay circuits D1 to Dn have delay characteristics different from each other. The delay circuits D1 to Dn receive a transmission timing signal, delay the signal according to each delay characteristic, and output a delayed transmission timing signal.
Here, the delay time (delay characteristic) of the delay circuit D1 is ΔT, the delay time of the delay circuit D2 is ΔT × 2, and the delay time of the delay circuit Dn is ΔT × n.
ΔT is a value obtained by converting the required distance measurement accuracy (measurement resolution) into time.
The latch circuits L <b> 1 to Ln hold the delayed transmission timing signals output from the delay circuits D <b> 1 to Dn with the reception timing signals from the receiving circuit 5, and output the held values to the distance calculation circuit 8.

Hereinafter, the operation of the wireless communication apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. 3 together with FIG. 1 and FIG.
First, the distance measurement signal is transmitted from the transmission circuit 3 to the second radio device 2 via the transmission antenna 4. The distance measurement signal from the first radio 1 is received by the receiving circuit 9 via the receiving antenna 10 and output to the folding circuit 11.
The distance measurement signal is output to the transmission circuit 12 as a return signal after a return time T4 in the return circuit 11. The return signal is transmitted from the transmission circuit 12 to the first wireless device 1 via the transmission antenna 13.
The return signal from the second radio 2 is received by the receiving circuit 5 via the receiving antenna 6.

  The transmission timing signal is output from the transmission circuit 3 to the delay time measurement circuit 7 at the transmission timing of the distance measurement signal. The reception timing signal is output from the reception circuit 5 to the delay time measurement circuit 7 at the reception timing of the return signal.

FIG. 3 is a timing chart showing a delay time measurement operation by the delay time measurement circuit 7 of FIG.
In FIG. 3, the transmission timing signals output from the transmission circuit 3 are delayed by different delay times (ΔT, ΔT × 2,..., ΔT × n) in the delay circuits D1 to Dn, respectively, so that the delayed transmission timing is obtained. A signal is output to each of the latch circuits L1 to Ln.
The delayed transmission timing signals output from the delay circuits D1 to Dn are held in the latch circuits L1 to Ln as the reception timing signals rise.

That is, in the delay transmission timing signal in which the delay time in the delay circuit Di (i = 1, 2,..., N) is shorter than the time difference between the reception timing signal and the transmission timing signal, “1” is held and output. Is done. Further, “0” is held and output for a delayed transmission timing signal in which the delay time in the delay circuit Di is longer than the time difference between the reception timing signal and the transmission timing signal.
Here, the delay time ΔT × i in the delay circuit Di in which the outputs of the latch circuits L1 to Ln change from “1” to “0” becomes the total delay time (delay time) Tt shown in Expression (1). .

  The total delay time Tt measured by the delay time measurement circuit 7 is output to the distance calculation circuit 8. In the distance calculation circuit 8, the above-mentioned known delay times T1, T3, T5, T6 and the turnaround time T4 are subtracted from the total delay time Tt to calculate the propagation time T2. Furthermore, the distance between the first radio device 1 and the second radio device 2 is calculated based on the propagation time T2 and the propagation speed of radio waves (300,000 km / sec).

According to the wireless communication apparatus according to the first embodiment of the present invention, the delay time measurement circuit 7 includes delay circuits D1 to Dn that are connected in parallel and have different delay characteristics, and are output from the delay circuits D1 to Dn. The total delay time Tt is measured by holding the delayed transmission timing signal as a reception timing signal, and the known delay times T1, T3, T5, T6 and the turn-back time T4 are subtracted to propagate between the radios. Time T2 is calculated.
Therefore, the reference timer is not involved in the measurement of the total delay time Tt and the propagation time T2, and the synchronization process can be made unnecessary.
Further, by measuring the total delay time Tt using the delay circuits D1 to Dn, it is not necessary to mount a reference timer that operates at a high frequency, so the total delay time Tt is measured with high accuracy without increasing power consumption. can do.

In addition, according to the wireless communication apparatus according to the first embodiment of the present invention, by using different radio frequencies for the transmission signal and the reception signal, structures such as walls and pillars that are problematic when the same frequency is used. There is an advantage that interference (interference) between a reflected signal of a transmission signal and a reception signal due to an object or the like can be avoided, and a decrease in distance measurement accuracy due to radio wave interference can be prevented.
That is, since the reflected signal has the same frequency as the transmission signal and the reception signal has a different frequency from the transmission signal, it is possible to clearly separate the two.

Embodiment 2. FIG.
In the first embodiment, the latch circuits L1 to Ln of the delay time measurement circuit 7 hold the delayed transmission timing signals output from the delay circuits D1 to Dn as the reception timing signals from the reception circuit 5, Without being limited thereto, the latch circuits L1 to Ln may hold the reception timing signal as a delayed transmission timing signal.

FIG. 4 is a block diagram showing in detail the delay time measuring circuit 7A of the wireless communication apparatus according to Embodiment 2 of the present invention.
In FIG. 4, the latch circuits L1 to Ln hold the reception timing signals from the reception circuit 5 with the delayed transmission timing signals output from the delay circuits D1 to Dn, and output the held values to the distance calculation circuit 8. .
Here, it is assumed that the reception timing signal has a pulse width of ΔT × 2.
Other configurations are the same as those in the first embodiment, and the description thereof is omitted.

FIG. 5 is a timing chart showing a delay time measurement operation by the delay time measurement circuit 7A of FIG. Note that the description of the same operation as in the first embodiment is omitted.
In FIG. 5, the transmission timing signal output from the transmission circuit 3 is delayed by different delay times (ΔT, ΔT × 2,..., ΔT × n) by the delay circuits D1 to Dn. A signal is output to each of the latch circuits L1 to Ln.
The value of the reception timing signal from the reception circuit 5 is held in each latch circuit L1 to Ln by the rise of the delayed transmission timing signal output from each delay circuit D1 to Dn.

That is, when the rising edge of the reception timing signal matches the rising edge of the delayed transmission timing signal output from each of the delay circuits D1 to Dn, “1” is held and output. In other cases, “0” is held and output.
Here, the delay time ΔT × i in the delay circuit Di in which the outputs of the latch circuits L1 to Ln are “1” is the total delay time (delay time) Tt shown in FIG.

According to the wireless communication apparatus according to the second embodiment of the present invention, the delay time measurement circuit 7A is connected in parallel and has the delay circuits D1 to Dn having different delay characteristics, and the reception timing signal is transmitted to each of the delay circuits D1 to Dn. The total delay time Tt is measured by holding the delayed transmission timing signal output from Dn.
Therefore, the same effect as in the first embodiment can be obtained.

In the second embodiment, the reception timing signal has a pulse width of ΔT × 2, but the pulse width of the reception timing signal is not limited to ΔT × 2, and is held by the delayed transmission timing signal. Need only have a sufficient width.
Also in this case, the same effects as those of the second embodiment can be obtained.

Embodiment 3 FIG.
In the first and second embodiments, the first radio 1 measures the distance to one second radio 2. However, the present invention is not limited to this, and the first radio 1 transmits one distance measurement signal. Thus, the distance to the plurality of second radio devices 2 may be measured.

FIG. 6 is an explanatory diagram showing the arrangement topology of the radios of the radio communication apparatus according to Embodiment 3 of the present invention.
In FIG. 6, three second radio devices 2 a to 2 c are arranged around the first radio device 1.
Here, the folding times in the folding circuits of the second radio devices 2a to 2c are set to values different from each other, and are set to the folding times T4a, T4b, and T4c, respectively. In addition, the time required for propagation of the distance measurement signal or the return signal from the first wireless device 1 to each of the second wireless devices 2a to 2c is defined as propagation times T2a, T2b, and T2c, respectively.

FIG. 7 is a block diagram showing a wireless communication apparatus according to Embodiment 3 of the present invention. Here, the first radio device 1 and the second radio device 2a are shown.
In FIG. 7, a folding time T4a is set in the folding circuit 11a.
The second radio devices 2b and 2c have the same configuration as that shown in FIG. 7, and individual return times T4b and T4c are set in the respective return circuits.
Other configurations are the same as those in the first embodiment, and the description thereof is omitted.

Hereinafter, the operation of the wireless communication apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. 8 together with FIG. 6 and FIG. Note that the description of the same operation as in the first embodiment is omitted.
FIG. 8 is a timing chart showing a delay time measurement operation according to the third embodiment of the present invention.
In FIG. 8, the distance measurement signal transmitted from the first radio device 1 is received by each of the second radio devices 2a to 2c. The distance measurement signals received by each of the second radio devices 2a to 2c are output to the transmission circuit 12 as a return signal after passing through different return times T4a, T4b, and T4c in the return circuit, and transmitted to the first radio device 1. The
The return times T4a, T4b, and T4c are set with sufficient timing margins so that the return signals of the second radio devices 2a to 2c do not overlap.

  Here, the total delay time Tta from the transmission of the distance measurement signal of the first wireless device 1 to the reception of the return signal of the second wireless device 2a is expressed by the following equation (2).

    Tta = T1 + T2a × 2 + T3 + T4a + T5 + T6 (2)

  Similarly, total delay times Ttb and Ttc from the transmission of the distance measurement signal of the first radio 1 to the reception of the return signals of the second radios 2b and 2c are expressed by the following equations (3) and (4). expressed.

Ttb = T1 + T2b × 2 + T3 + T4b + T5 + T6 (3)
Ttc = T1 + T2c × 2 + T3 + T4c + T5 + T6 (4)

  In the equations (2) to (4), values other than the propagation times T2a, T2b, and T2c are all known values as device specifications as described above.

  The delay time measurement circuit 7 uses the delayed transmission timing signal output from each of the delay circuits D1 to Dn and the reception timing signal output at the reception timing of the return signal from each of the second radio devices 2a to 2c. Thus, the total delay times Tta, Ttb, and Ttc are measured in the same manner as in the first and second embodiments.

  These total delay times Tta, Ttb, and Ttc measured by the delay time measurement circuit 7 are output to the distance calculation circuit 8. In the distance calculation circuit 8, the known delay times T1, T3, T5, T6 and the different folding times T4a, T4b, T4c are subtracted from the total delay times Tta, Ttb, Ttc, respectively, and propagation times T2a, T2b, T2c are obtained. Calculated. Furthermore, the distance between the first radio 1 and each of the second radios 2a to 2c is calculated based on the propagation times T2a, T2b, T2c and the radio wave propagation speed (300,000 km / sec).

  According to the wireless communication apparatus according to Embodiment 3 of the present invention, by setting different return times T4a, T4b, and T4c in the return circuits of the second wireless devices 2a to 2c, the first wireless device 1 By transmitting the distance measurement signal once, the distance from the plurality of second radio devices 2a to 2c can be measured in a time division manner.

In the third embodiment, the case where there are three second radio devices 2 has been described. However, the present invention is not limited to this, and the number of second radio devices 2 may be two, or four or more. It may be.
Also in this case, by setting the turn-back time T4 so that the turn-back signals from the second radio devices 2 do not overlap, the distance to the plurality of second radio devices 2 is measured by transmitting the distance measurement signal once. be able to.

Embodiment 4 FIG.
In a network system using short-range wireless technology such as a wireless sensor node (wireless device), it is important that the wireless sensor node detects its own installation position. As a method, the wireless sensor node measures the distance from three or more wireless devices whose installation positions are known, and determines its own installation position by three-point positioning.
However, in wireless communication, there may be a case where the delay time and the actual distance between the wireless devices do not match due to radio wave attenuation or interference.

In the first to third embodiments, the distance between the first radio device 1 and the second radio device 2 is measured using only the total delay time Tt output from the delay time measurement circuit 7, but the delay is as described above. There may be a case where the time and the actual distance between the radios do not match.
Therefore, the first wireless device 1 determines the communication quality with the second wireless device 2 based on the radio wave intensity in addition to the total delay time Tt, and considers the communication quality and determines the distance to the second wireless device 2. It is desirable to calculate.

FIG. 9 is an explanatory diagram showing the arrangement topology of the radios of the radio communication apparatus according to Embodiment 4 of the present invention.
In FIG. 9, five second radio devices 2d to 2h are arranged around the first radio device 1A. Here, it is assumed that the installation positions of the second wireless devices 2d to 2h are already known.

FIG. 10 is a block diagram showing a wireless communication apparatus according to Embodiment 4 of the present invention. Here, the first radio device 1A and the second radio device 2d are shown.
The second radio devices 2e to 2h have the same configuration as that in FIG. In addition, at least three second radio devices 2d to 2h are provided.

In FIG. 10, the receiving circuit 5A of the first radio device 1A includes radio wave intensity measuring means (not shown) for measuring the radio wave strength of the return signals from the second radio devices 2d to 2h.
The first radio 1A includes a distance calculation / communication quality determination circuit (distance calculation means, communication quality determination means) 14 instead of the distance calculation circuit 8 shown in FIG.

The distance calculation / communication quality determination circuit 14 calculates the distance between the first radio 1A and each of the second radios 2d to 2h based on the total delay time Tt measured by the delay time measurement circuit 7. Further, the communication quality (reliability of the total delay time) with each of the second wireless devices 2d to 2h is determined based on the radio wave intensity measured by the receiving circuit 5A.
The distance calculation / communication quality determination circuit 14 further includes position identification means (not shown) for identifying its own position.

The position identification means selects three radio devices whose communication quality satisfies a predetermined condition from the second radio devices 2d to 2h, and uses the delay time with each selected second radio device 2d to 2h. Perform point positioning and identify your position.
The position identifying means determines that the above predetermined condition is satisfied when the radio wave intensity is equal to or greater than a predetermined intensity that is set arbitrarily, or the radio wave intensity fluctuation amount is equal to or less than a predetermined fluctuation amount that is arbitrarily set. When it is, it determines with satisfy | filling said predetermined conditions.
Other configurations are the same as those in the first embodiment, and the description thereof is omitted.

The communication quality determination operation according to the fourth embodiment of the present invention will be described below with reference to the flowchart of FIG. 11 together with FIGS.
First, the transmission circuit 3 transmits a distance measurement signal to measure the radio field intensity to each of the second radio devices 2d to 2h (step S21).
Subsequently, the receiving circuit 5A receives a return signal obtained by returning the distance measurement signal by each of the second radio devices 2d to 2h (step S22), and measures the radio wave intensity when the return signal is received (step S23).

Subsequently, the distance calculation / communication quality determination circuit 14 determines whether or not the number of receptions of the return signal has reached the specified number (step S24).
That is, when the radio wave interference is strong, it is assumed that the fluctuation of the radio wave intensity of the return signal becomes large. Therefore, the distance calculation / communication quality determination circuit 14 measures the radio field intensity a plurality of times, and determines the communication quality with each of the second radio devices 2d to 2h using the fluctuation amount of the radio field intensity.

If it is determined in step S24 that the number of receptions has reached the specified number (that is, Yes), the communication quality with each of the second radio devices 2d to 2h is determined based on the measured radio field intensity (step S24). S25).
Subsequently, the delay time measurement circuit 7 receives the return signals of the second radio devices 2d to 2h from the transmission of the distance measurement signal of the first radio device 1A in the same manner as in the first and second embodiments. Until the total delay time Tt is measured (step S26), and the process of FIG.

  On the other hand, if it is determined in step S24 that the number of receptions has not reached the specified number (that is, No), the process returns to step S21 again.

Subsequently, the position identifying operation of the position identifying unit according to the fourth embodiment of the present invention will be described with reference to FIGS. 9 to 11 and FIG.
FIG. 12 is an explanatory diagram illustrating a determination result when the communication quality is determined for each of the second radio devices 2d to 2h in FIG.
In FIG. 12, the minimum radio field intensity is a ratio of the radio field intensity at the time of reception to the radio field intensity at the time of transmission, and the radio field intensity fluctuation amount is the fluctuation of the radio field intensity at the time of reception with respect to the radio field intensity at the time of transmission. The quantity (difference between the maximum and minimum values) is expressed as a percentage.

First, the position identifying means determines whether or not the minimum radio field intensity is a predetermined intensity (for example, 50%) or more.
In FIG. 12, since the radio field intensity of the second radio 2g is 30%, which is lower than the predetermined intensity, the position identifying unit determines that the second radio 2g does not satisfy the predetermined condition.
In addition, the position identification unit determines whether or not the radio field intensity fluctuation amount is a predetermined fluctuation amount (for example, 30%) or less.
In FIG. 12, since the radio field intensity fluctuation amount of the second radio device 2e is 40%, which is higher than the predetermined fluctuation amount, the position identification unit determines that the second radio device 2e does not satisfy the predetermined condition.

Based on the determination result, the position identification unit selects the second radio devices 2d, 2f, and 2h that satisfy the predetermined condition, and identifies the position using the delay time for the second radio devices 2d, 2f, and 2h.
That is, in FIG. 12, the three-point positioning is executed using the distance measurement values with the second radio devices 2d, 2f, and 2h to identify the position of itself.

According to the wireless communication apparatus according to the fourth embodiment of the present invention, the position identification unit selects the three second wireless devices 2d to 2h based on the communication quality, and the selected second wireless devices 2d to 2h By executing the three-point positioning using the delay time, the position of itself is identified.
Therefore, it is possible to exclude the second wireless devices 2d to 2h, which are considered to have a delay time that does not match the actual distance between the wireless devices due to the attenuation of radio waves or interference. Identification can be performed.

In the first to fourth embodiments, the first radio device 1 and the second radio device 2 have been described as including the transmission antennas 4 and 13 and the reception antennas 6 and 10, respectively. However, the present invention is not limited to this.
When radio waves in the same frequency band are used for the distance measurement signal and the return signal, the transmission antenna and the reception antenna may be integrated into a transmission / reception antenna.
That is, as shown in FIG. 13, the first radio 1 </ b> B may have a transmission / reception antenna 15, and the second radio 2 </ b> B may have a transmission / reception antenna 16.
Also in this case, the same effect as in the first to fourth embodiments can be obtained by assigning different frequency channels to the transmission signal and the reception signal within the same frequency band.

It is a block diagram which shows the radio | wireless communication apparatus which concerns on Embodiment 1 of this invention. FIG. 2 is a block diagram illustrating in detail a delay time measurement circuit in FIG. 1. 3 is a timing chart showing a delay time measurement operation by the delay time measurement circuit of FIG. 2. It is a block diagram which shows in detail the delay time measuring circuit of the radio | wireless communication apparatus which concerns on Embodiment 2 of this invention. 5 is a timing chart showing a delay time measurement operation by the delay time measurement circuit of FIG. 4. It is explanatory drawing which shows the arrangement | positioning topology of the radio | wireless machine of the radio | wireless communication apparatus which concerns on Embodiment 3 of this invention. It is a block diagram which shows the radio | wireless communication apparatus which concerns on Embodiment 3 of this invention. It is a timing chart which shows the measurement operation of the delay time by Embodiment 3 of this invention. It is explanatory drawing which shows the arrangement | positioning topology of the radio | wireless machine of the radio | wireless communication apparatus which concerns on Embodiment 4 of this invention. It is a block diagram which shows the radio | wireless communication apparatus which concerns on Embodiment 4 of this invention. Reference is made to a flowchart showing a communication quality determination operation according to Embodiment 4 of the present invention. It is explanatory drawing which shows the determination result at the time of determining communication quality about each 2nd radio | wireless machine of FIG. It is another block diagram which shows the radio | wireless communication apparatus which concerns on Embodiment 1-4 of this invention.

Explanation of symbols

  1, 1A, 1B 1st radio, 2, 2a to 2h, 2B 2nd radio, 3 transmission circuit (transmission means), 5 reception circuit (reception means), 5A reception circuit (reception means, intensity detection means), 7, 7A Delay time measurement circuit (delay time measurement means), 8 Distance calculation circuit (distance calculation means), 11, 11a Folding circuit (folding means), 14 Distance calculation / communication quality judgment circuit (distance calculation means, communication quality judgment) Means), D1 to Dn delay circuit (delay element), Tt total delay time (delay time).

Claims (7)

A first wireless device and a second wireless device that wirelessly communicate with each other;
The first radio is
A transmission means for transmitting a transmission signal to the second radio and outputting a transmission timing signal at a transmission timing of the transmission signal;
Receiving means for receiving a reception signal returned by the second radio device and outputting a reception timing signal at a reception timing of the reception signal;
In response to the transmission timing signal and the reception timing signal, a delay time measuring unit that measures a time difference between the reception timing signal and the transmission timing signal as a delay time;
A distance calculating means for calculating a distance between the first radio and the second radio based on the delay time;
The delay time measuring means includes a plurality of delay elements connected in parallel and having different delay characteristics, a delayed transmission timing signal obtained by delaying the transmission timing signal via the plurality of delay elements, and the reception timing signal And measuring the delay time using a wireless communication device.   The wireless communication apparatus according to claim 1, wherein the delay time measuring unit measures the delay time by holding the delayed transmission timing signal using the reception timing signal.   The wireless communication apparatus according to claim 1, wherein the delay time measuring unit measures the delay time by holding the reception timing signal using the delayed transmission timing signal. A plurality of the second radio devices are provided, and each second radio device includes a return means for returning and transmitting the transmission signal at an individual return time,
4. The wireless communication apparatus according to claim 1, wherein a different value is set for each of the second wireless devices as the return time. 5. There are at least three second radio units,
The receiving means further includes radio wave intensity measuring means for measuring the radio wave intensity of the received signal,
The distance calculation means further includes communication quality determination means for determining communication quality with each second radio based on the radio field intensity, and position identification means for identifying its own position,
The position identification means includes
2. A second radio having the communication quality satisfying a predetermined condition is selected, and its own position is identified based on three-point positioning using a delay time with the selected second radio. The wireless communication device according to any one of claims 1 to 4.   The wireless communication apparatus according to claim 5, wherein the position identification unit determines that the predetermined condition is satisfied when the radio wave intensity is equal to or higher than a predetermined intensity.   The wireless communication apparatus according to claim 5 or 6, wherein the position identification unit determines that the predetermined condition is satisfied when a fluctuation amount of the radio wave intensity is equal to or less than a predetermined fluctuation amount.

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