WO2016035418A1 - Distance measurement system, distance measurement device, device that is measured, and position detection system - Google Patents

Abstract

This distance measurement system comprises a detected device 2 and a distance measurement device for calculating the distance to the detected device 2. The detected device 2 is provided with a transmission unit 6 which synchronizes the phases of and wirelessly transmits a first signal of frequency f₁ and a second signal of frequency f₂ different from that of the first signal. The distance measurement device is provided with a receiving unit which receives the first signal and the second signal, and a calculation unit which calculates the distance from the distance measurement device to the detected device 2 on the basis of the phase difference between the received first signal and second signal.

Description

Distance measurement system, distance measurement device, device under measurement, and position detection system

The present invention relates to a distance measurement system, a distance measurement device, a device under measurement, and a position detection system using radio waves.

In order to measure the distance to a predetermined measurement object, a distance measuring sensor using light such as laser light or electromagnetic waves may be used. Such a distance measuring sensor projects light or electromagnetic waves on a measurement object and receives the reflected light, thereby obtaining a distance from the time until the reflected light is received, or the projected light and reflected light. There is one that obtains the distance based on the phase difference between the two (see, for example, Patent Document 1).

JP-A-10-206544

In the above distance measuring sensor, since it is necessary to project light to the measurement target and receive the reflected light, for example, when there is an obstacle between the measurement target and the measurement target is a moving object Therefore, it is impossible to measure accurately.

The present invention has been made in view of such circumstances, and an object thereof is to provide a technique capable of accurately measuring the distance to a measurement object.

A distance measurement system according to an embodiment is a distance measurement system including a device under measurement and a distance measurement device that obtains a distance to the device under measurement, wherein the device under measurement has a first frequency of a predetermined frequency. A transmission unit that wirelessly transmits a signal and a second signal having a frequency different from that of the first signal in phase synchronization, and the distance measuring device includes a reception unit that receives the first signal and the second signal; A calculation unit that obtains a distance from the distance measuring device to the device under measurement based on a phase difference between the received first signal and the second signal.

A distance measuring device according to an embodiment is a distance measuring device that determines a distance to a device under measurement, and is a wirelessly transmitted first signal having a predetermined frequency and a frequency different from the first signal and having a phase. A receiving unit that receives the second signal synchronized with each other, and a calculation unit that obtains a distance from the device to the device to be measured based on a phase difference between the received first signal and the second signal. I have.

An apparatus to be measured according to an embodiment is a device to be measured that causes a distance measurement device to obtain a distance to the distance measurement device, and is a distance from the distance measurement device to the device to be measured based on a mutual phase difference. A transmitter that wirelessly transmits a first signal having a predetermined frequency for obtaining the second signal and a second signal having a frequency different from the first signal in phase synchronization.

A position detection system according to an embodiment is a position detection system including a detected device and a position detecting device that detects a position of the detected device, and the detected device has a predetermined frequency. A transmission unit configured to wirelessly transmit a first signal and a second signal having a frequency different from that of the first signal in a phase-synchronized manner; the position detection device includes: a plurality of distance measurement units; and the plurality of distance measurement units A detection unit that detects the position of the device to be detected based on the distances from the plurality of distance measurement units to the detected device, respectively, and each of the plurality of distance measurement units has the first signal. And a reception unit that receives the second signal, and a calculation unit that obtains a distance from each distance measurement unit to the detected device based on a phase difference between the received first signal and the second signal. I have.

According to the present invention, the distance to the measurement object can be measured with high accuracy, and the position of the measurement object can be detected with high accuracy.

1 is a diagram illustrating an overall configuration of a position detection system according to a first embodiment. It is a block diagram which shows the principal part structure of a to-be-detected apparatus. It is a figure which shows the aspect at the time of producing | generating a 1st pulse signal and a 2nd pulse signal. It is a figure which shows a part of frequency spectrum of a 1st pulse signal. It is a block diagram which shows the structure of a distance measurement part. It is a block diagram which shows the principal part structure of the to-be-detected apparatus which concerns on a modification. It is a block diagram which shows the principal part structure of the to-be-detected apparatus with which the position detection system which concerns on 2nd Embodiment is provided. It is a figure which shows a part of frequency spectrum of a pulse signal. It is a figure which shows the 2 input delta-sigma modulator used in order to produce | generate a pulse signal in 2nd Embodiment.

[Description of Embodiment of Present Invention]
When the measurement target of the distance measurement is a mobile object, if a known wireless signal is transmitted to the measurement target, the light from the measurement target can be transmitted without projecting light and receiving reflected light as in the conventional example. There is a possibility that a wireless signal is received and the distance can be obtained with high accuracy based on the phase of the wireless signal.

Here, when a known radio signal is transmitted to the measurement target, it is necessary that time is synchronized between the measurement target side (transmission side) that transmits the radio signal and the reception side. This is because it is necessary to specify the phase of the radio signal when transmitted from the measurement object, which is a reference for obtaining the distance.

However, when time synchronization is performed between the transmission side and the reception side, a function for exchanging time information is required on both the transmission side and the reception side, and the configuration becomes complicated.

Also, since the power of the radio signal transmitted from the measurement target side has a correlation with the propagation distance, information on the distance can be obtained based on the received power of the received radio signal. In this case, information about the distance can be obtained without performing time synchronization between the transmitting side and the receiving side, but the received power is easily influenced by factors other than the distance, and compared with the distance measurement based on the phase. Measurement accuracy is lowered.

For this reason, there is a demand for a method that can accurately measure the distance using a radio signal even when the transmission side and the reception side are asynchronous.

First, the contents of the embodiments of the present invention will be listed and described.
(1) A distance measurement system according to an embodiment is a distance measurement system including a device under measurement and a distance measurement device for obtaining a distance to the device under measurement, wherein the device under measurement has a predetermined frequency. And a transmitter that wirelessly transmits a first signal of a frequency different from that of the first signal in phase synchronization, and the distance measuring device receives the first signal and the second signal. A receiving unit; and a calculation unit that obtains a distance from the distance measuring device to the device under measurement based on a phase difference between the received first signal and the second signal.

According to the distance measuring system configured as described above, the first signal and the second signal transmitted in phase synchronization with each other in the device under test are received, and the phase difference is obtained from the distance measuring device. Since the distance to the device under test is determined, the distance can be measured accurately even when there is an obstacle between the device under measurement and the device under test moving. it can.
Further, since the distance is obtained based on the phase difference between the first signal and the second signal, it is not necessary to synchronize the time between the device under measurement and the distance measuring device, and the distance can be obtained with a simple configuration with high accuracy. be able to.

(2) In the distance measurement system, the transmission unit of the device under measurement has a signal pattern for outputting a first digital signal including the first signal and a second digital signal including the second signal. The stored memory unit, and the first digital signal and the second digital signal based on the signal pattern are acquired from the memory unit, and the first signal and the second digital signal included in the first digital signal are obtained. It is preferable to include a control unit that wirelessly transmits the second signal included in a phase-synchronized manner.
In this case, since the first digital signal and the second digital signal are output from the memory unit and the first signal and the second signal are wirelessly transmitted, the phase between the first signal and the second signal is transmitted in synchronization. It becomes easy.

(3) In the distance measurement system, it is preferable that the first digital signal and the second digital signal are pulse signals obtained by performing ΔΣ modulation on the first signal and the second signal.

(4) The memory unit may store one signal pattern for outputting a pulse signal including both the first signal and the second signal as the signal pattern.
In this case, since the first signal and the second signal are included in one modulation signal and output, the phase between the first signal and the second signal can be reliably synchronized.
(5) In addition, the memory unit outputs a first signal pattern for outputting a pulse signal including the first signal and a pulse signal including the second signal as the signal pattern. Two signal patterns may be stored.
In this case, it becomes easy to change the combination of the first signal pattern and the second signal pattern, and the combination of the first signal and the second signal can be easily changed according to the measurement distance or the like.

(6) Moreover, it is preferable that the frequency of the first signal and the frequency of the second signal are set to values at which the first signal and the second signal can be transmitted and received by a single antenna. .
In this case, since the first signal and the second signal can be transmitted and received with a single antenna, the configuration can be simplified.
Further, since the frequency of the first signal and the frequency of the second signal are included in a relatively narrow band, it is possible to suppress the influence on the transmission path characteristics of the parent's name due to the difference in frequency, and to obtain the distance more accurately. be able to.

(7) A distance measuring device according to an embodiment is a distance measuring device that calculates a distance to a device under measurement, and is transmitted by a wirelessly transmitted first signal having a predetermined frequency and a frequency different from the first signal. A receiving unit that receives a second signal that is synchronized in phase, and a calculation unit that obtains a distance from the device itself to the device under test based on a phase difference between the received first signal and the second signal. And.

(8) A device under measurement according to an embodiment is a device under measurement that causes a distance measurement device to obtain a distance to the distance measurement device, and is based on the phase difference between the distance measurement device and the device under measurement. A transmission unit that wirelessly transmits a first signal having a predetermined frequency for obtaining the distance to the second signal and a second signal having a frequency different from that of the first signal in phase synchronization.

According to the distance measuring device and the device under measurement configured as described above, the distance from the distance measuring device to the device under measurement can be obtained with high accuracy.

(9) In the device under measurement, the transmission unit of the device under measurement has a signal pattern for outputting a first digital signal including the first signal and a second digital signal including the second signal. The stored memory unit, and the first digital signal and the second digital signal based on the signal pattern are acquired from the memory unit, and the first signal and the second digital signal included in the first digital signal are obtained. It is preferable to include a control unit that wirelessly transmits the second signal included in a phase-synchronized manner.

(10) A position detection system according to an embodiment is a position detection system including a detected device and a position detecting device that detects a position of the detected device, and the detected device has a predetermined frequency. The first signal and a second signal having a frequency different from that of the first signal are wirelessly transmitted with their phases synchronized with each other, and the position detection device includes a plurality of distance measurement units, Each of the plurality of distance measurement units, and a detection unit that detects the position of the detected device based on the distance from the plurality of distance measurement units to the detected device, each of the plurality of distance measurement units, A receiving unit that receives the first signal and the second signal, a phase difference between the received first signal and the second signal, and a detected device from each distance measuring unit based on these phase differences An arithmetic unit for calculating the distance to It is provided.

According to the position detection system having the above configuration, the distance from the distance measuring unit to the detected device can be obtained with high accuracy, and therefore the position of the measured device can be detected with high accuracy.

[Details of the embodiment of the present invention]
Hereinafter, preferred embodiments will be described with reference to the drawings.
Note that at least a part of each embodiment described below may be arbitrarily combined.
[1 About the first embodiment]
FIG. 1 is a diagram illustrating an overall configuration of a position detection system according to the first embodiment.
The position detection system 1 includes a detected device 2 and a position detecting device 3 that detects the position of the detected device 2.

The detection device 2 includes a first signal frequency f ₁ is a predetermined frequency and a second signal frequency f ₁ and a different frequency f _2, the function of wirelessly transmitted to each other by phase-synchronized.
The position detecting device 3 receives the first signal and the second signal transmitted from the detected device 2 and obtains the distance to the detected device 2, and the detected device 2 obtained by the distance measuring unit 4. And a detection unit 5 that detects the position of the detected device 2 based on the distance up to.

The position detection device 3 includes a plurality of distance measuring units 4 (three in the illustrated example). Each distance measuring unit 4 has a function of receiving the first signal and the second signal from the detected device 2 and obtaining the distance to the detected device 2.

FIG. 2 is a block diagram illustrating a configuration of a main part of the detected device 2.
As shown in the figure, the device to be detected 2 includes a transmission unit 6 for transmitting the first signal and the second signal.
The transmission unit 6 includes a signal output unit 7, a first band pass filter (first BPF) 8 to which a signal output from the signal output unit 7 is provided, and a second band pass to which a signal output from the signal output unit 7 is provided. A filter (second BPF) 9 and an antenna 10 are provided.

The signal output unit 7 includes a control unit 11 and a memory unit 12.
The memory unit 12 has a function of storing various data in the storage area. The memory unit 12 stores a first pulse signal pattern 13 and a second pulse signal pattern 14.
The first pulse signal pattern 13 is a pattern in which the first pulse signal generated in advance is stored in the memory unit 12 as a pattern. Therefore, if the memory unit 12 outputs a signal according to the first pulse signal pattern 13, the memory unit 12 can output the first pulse signal.
Similarly, the second pulse signal pattern 14 is a pattern in which a second pulse signal generated in advance is stored in the memory unit 12 as a pattern. The memory unit 12 outputs a signal according to the second pulse signal pattern 14. The second pulse signal can be output.

The first pulse signal (first digital signal) is a digital modulation signal obtained by subjecting the first signal to ΔΣ modulation, and includes the first signal as a main signal component.
The second pulse signal (second digital signal) is a digital modulation signal obtained by subjecting the second signal to ΔΣ modulation, and includes the second signal as a main signal component.

FIG. 3 is a diagram illustrating an aspect when the first pulse signal and the second pulse signal are generated.
As shown in the figure, the first pulse signal (second pulse signal) is generated in advance by applying a first signal (second signal) to a bandpass delta-sigma modulator (DSM: Band Pass Delta-Sigma Modulator) 15. Is done.
The ΔΣ modulator 15 performs ΔΣ modulation on the given first signal (second signal), and outputs a first pulse signal (second pulse signal) that is a quantized signal. The sampling frequency f _S of the ΔΣ modulator 15 is set to be larger than the frequency f ₁ of the first signal (frequency f ₂ of the second signal) given to the ΔΣ modulator 15 (f ₁ (f ₂ ) <f _S ).

FIG. 4 is a diagram illustrating a part of the frequency spectrum of the first pulse signal.
As shown in the figure, the first pulse signal includes the first signal having the frequency f ₁ as the main signal component. Further, the first pulse signal includes a quantization noise component generated by ΔΣ modulation in a band other than the band near the frequency f ₁ .
The frequency spectrum of the second pulse signal is also includes a second signal of frequency f ₂ as the main signal component, in addition to the band other than the band of the frequency f ₂ vicinity, including quantization noise component generated by the ΔΣ modulation This is almost the same as FIG.

Returning to FIG. 2, the memory unit 12 converts the first pulse signal and the second pulse signal into the first pulse signal and the second pulse signal generated by performing ΔΣ modulation on the first signal and the second signal as described above. It is stored as a pattern for outputting as a signal.
The memory unit 12 outputs a first pulse signal and a second pulse signal by outputting a signal according to the first pulse signal pattern 13 and the second pulse signal pattern 14 according to the control of the control unit 11.
Thus, the signal output unit 7 in the transmission unit 6 of the device to be detected 2 outputs the first pulse signal including the first signal, thereby outputting the first signal as a digital signal. The signal output unit 7 outputs the second signal as a digital signal by outputting a second pulse signal including the second signal.

The memory unit 12 gives the output first pulse signal to the first BPF 8 and gives the second pulse signal to the second BPF 9.
The 1BPF8 is a band-pass filter of the analog, among signal components included in the first pulse signal is a digital signal provided from the memory unit 12, the frequency f ₁ of input signal components including a first signal as an analog signal It is configured to pass and block the passage of quantization noise components in other bands.
The antenna 10 is connected to the subsequent stage of the first BPF 8. The first BPF 8 gives a passing signal that is an analog signal passing through the first BPF 8 to the antenna 10.
Therefore, when the first pulse signal is given from the memory unit 12, the first BPF 8 passes the signal component near the frequency f ₁ as a passing signal, and gives the first signal included in the passing signal to the antenna 10.

Similarly to the first BPF 8, the second BPF 9 is an analog band-pass filter, and among the signal components included in the second pulse signal that is a digital signal supplied from the memory unit 12, a signal in the vicinity of the frequency f ₂ including the second signal. The components are passed as analog signals, and the quantization noise components in other bands are blocked from passing.
An antenna 10 is connected to the subsequent stage of the second BPF 9. The second BPF 9 gives the antenna 10 a passing signal that is an analog signal passing through the second BPF 9.
Therefore, the 2BPF9, when the second pulse signal from the memory unit 12 is supplied, passed through a frequency f ₂ near the signal component as a passing signal, providing a second signal included in the passing signal to the antenna 10.

The antenna 10 radiates the first signal and the second signal given from the first BPF 8 and the second BPF 9 to space.
As described above, the transmission unit 6 can wirelessly transmit the first signal and the second signal from the antenna 10.
Note that the frequency f _{1 of} the first signal and the frequency f ₂ of the second signal are set to values at which the first signal and the second signal can be transmitted and received by a single antenna. Also in the antenna 10, the frequency f ₁ of the first signal, in accordance with the frequency f ₂ of the second signal are set so as to be able to both emit a first signal and a second signal.

The control unit 11 has a function of controlling the memory unit 12 and causing the memory unit 12 to output the first pulse signal and the second pulse signal.
The control unit 11 controls the memory unit 12 to output the first pulse signal and the second pulse signal simultaneously. Usually, in the memory, data is stored in units of 8 to 32 bits for each address (accessible unit). Using this structure, for example, the first pulse signal pattern 13 and the second pulse signal pattern 14 are stored in one unit of address 1, and the control unit 11 can read data from the address 1 of the memory unit 12. For example, both patterns 13 and 14 included in one unit of address 1 can be read out almost simultaneously, and the first pulse signal and the second pulse signal can be output in synchronization.

Thereby, the memory unit 12 can always output the phase relationship between the first signal included in the first pulse signal and the second signal included in the second pulse signal in the same state.
Thereby, the transmission unit 6 is configured to wirelessly transmit the phase-synchronized phase so that the phase of the first signal and the phase of the second signal are the same.
That is, the control unit 11 of the transmission unit 6 acquires the first pulse signal and the second pulse signal from the memory unit 12, and phase-synchronizes the first signal and the second signal included in the first pulse signal and the second pulse signal. Wireless transmission.

FIG. 5 is a block diagram showing a configuration of the distance measuring unit 4. In the illustrated example, one distance measuring unit 4 is shown, but the other distance measuring units 4 have the same configuration.
The distance measurement unit 4 receives a reception signal 17 including a first signal and a second signal transmitted from the detected device 2 via the antenna 16, and based on the received first signal and second signal. And a calculation unit 18 for obtaining a distance to the detected device 2.

When the reception unit 17 receives the reception signal including the first signal and the second signal by the antenna 16 that is a single antenna, the reception unit 17 performs amplification processing, A / D conversion processing, and the like on the reception signal. The receiving unit 17 gives the received signal that has undergone processing such as A / D conversion to the computing unit 18.

The calculation unit 18 includes a first phase detection unit 19 for detecting the phase of the first signal included in the reception signal, and a second phase detection unit 20 for detecting the phase of the second signal included in the reception signal. It has.
A reception signal from the reception unit 17 is given to each of the first phase detection unit 19 and the second phase detection unit 20.
The first phase detector 19 has a function of detecting and outputting the phase of the first signal from the signal component of the first signal included in the received signal when the received signal is given.
The second phase detector 20 has a function of detecting and outputting the phase of the second signal from the signal component of the second signal included in the received signal when the received signal is given.

Further, the calculation unit 18 is provided with the phase of the first signal output from the first phase detection unit 19 and the phase of the second signal output from the second phase detection unit 20, and obtains a phase difference between the two phases. 21 and a processing unit 22 that obtains the distance from the distance measuring unit 4 that is the device itself to the detected device 2 based on the phase difference between the two phases output from the adder 21.

Here, the calculation for obtaining the distance from the distance measurement unit 4 to the detected device 2 performed in the calculation unit 18 of the distance measurement unit 4 will be described.

When the signal Tx1 when the first signal is transmitted from the detected device 2 is expressed by the following formula (1), the signal Rx1 when the first signal is received by the distance measuring unit 4 is expressed by the following formula (2 ).
Tx1 = Acos (ω ₁ t) (1)
Rx1 = Ae− ^αr cos (ω ₁ (t−τ))
= Ae ^−αr cos (ω ₁ t−ω ₁ τ) (2)

In the above formulas (1) and (2), t is the time, τ is the time required for the first signal to be transmitted and received, A is the amplitude, ω ₁ is the angular frequency of the first signal, and r is the distance measurement. The distance from the unit 4 to the detected device 2, α represents a constant indicating the attenuation characteristic of the signal according to the distance.

Similarly, when the signal Tx2 when the second signal is transmitted from the detected device 2 is expressed by the following equation (3), the signal Rx2 when the second signal is received by the distance measuring unit 4 is The following equation (4).
Tx2 = Acos (ω ₂ t) (3)
Rx2 = Ae− ^αr cos (ω ₂ (t−τ))
= Ae ^−αr cos (ω ₂ t−ω ₂ τ) (4)

In the above formulas (3) and (4), ω ₂ indicates the angular frequency of the second signal.

In the above formulas (2) and (4), the first signal and the second signal are wirelessly transmitted from the detected apparatus 2 in a phase-synchronized state so as to be in phase with each other. It can be considered that the relationship between 2) and equation (4) is the same.
Further, since both the first signal and the second signal are transmitted from the detected device 2 and received by the distance measuring unit 4, τ is considered to be the same in the relationship between the equations (2) and (4). be able to.

Therefore, the phase difference Δθ between the phase of Rx1 which is a signal when the first signal is received by the distance measuring unit 4 and the phase of Rx2 which is the signal when the second signal is received by the distance measuring unit 4 is From the above formulas (2) and (4), the following formula (5) can be obtained.
Phase difference Δθ = ω ₂ τ-ω ₁ τ
= (Ω ₂ −ω ₁ ) τ (5)

ω1 and ω2 are known values. Further, τ can be expressed as in the following formula (6).
τ = r / c (6)

In the above formula (6), r represents the distance from the distance measuring unit 4 to the detected device 2 as described above. c shows the speed of electromagnetic waves.
Therefore, if the phase difference Δθ between the phase of Rx1 and the phase of Rx2 is obtained, r that is the distance from the distance measuring unit 4 to the detected device 2 can be obtained.

As described above, in the calculation unit 18, the first phase detection unit 19 detects the phase of the received first signal, and the second phase detection unit 20 detects the phase of the received second signal.
Further, the adder 21 obtains a phase difference from the phase of the first signal and the phase of the second signal given from the detection units 19 and 20.
That is, the detection units 19 and 20 and the adder 21 obtain a phase difference Δθ between the phase of Rx1 and the phase of Rx2.

The adder 21 gives the calculated phase difference Δθ to the processing unit 22. The processing unit 22 performs calculation according to the above formulas (5) and (6) using the given phase difference Δθ, and obtains the distance r from the distance measuring unit 4 to the detected device 2.

As described above, the distance measuring unit 4 can obtain the distance from the distance measuring unit 4 to the detected device 2.
That is, the device to be detected 2 as the device to be measured and the distance measuring unit 4 as the distance measuring device constitute a distance measuring system that obtains the distance from the distance measuring unit 4 to the device to be detected 2.

According to the distance measuring system, the distance measuring unit 4 receives the first signal and the second signal transmitted in phase-synchronized state with each other in the device to be detected 2 (device to be measured), and obtains the phase difference therebetween. Since the distance from the (distance measuring device) to the detected device 2 is obtained, even when there is an obstacle between the measured device 2 to be measured and the detected device 2 is moving The distance can be measured with high accuracy.
In addition, since the distance is obtained based on the phase difference between the first signal and the second signal, it is not necessary to synchronize the time between the detected device 2 and the distance measuring unit 4, and the distance is accurate with a simple configuration. Can be requested.

In the present embodiment, the transmission unit 6 of the detected device 2 is based on the memory unit 12 that stores the first pulse signal pattern 13 and the second pulse signal pattern 14, and both signal patterns 13 and 14 from the memory unit 12. The first pulse signal (first digital signal) and the second pulse signal (second digital signal) are acquired, and the first signal included in the first pulse signal and the second signal included in the second pulse signal are phase-shifted. And a control unit 11 that performs wireless transmission in synchronization.
In this case, since the first pulse signal and the second pulse signal are output from the memory unit and the first signal and the second signal are wirelessly transmitted, the phase between the first signal and the second signal is transmitted in synchronization. It becomes easy.

In the present embodiment, the frequency f _{1 of} the first signal and the frequency f ₂ of the second signal are set to values that allow the first signal and the second signal to be transmitted and received by a single antenna.
Therefore, since the first signal and the second signal can be transmitted and received by the antennas 10 and 16 that are single antennas, the configuration can be simplified.
Further, since the frequency f ₁ of the first signal and the frequency f ₂ of the second signal are included in a relatively narrow band, the influence on the transmission path characteristics of both signals due to the difference in frequency can be suppressed, and the accuracy is improved. You can often find the distance.

In the present embodiment, the memory unit 12 includes, as signal patterns, a first pulse signal pattern 13 (first signal pattern) for outputting a first pulse signal including the first signal, and a second signal. The second pulse signal pattern 14 (second signal pattern) for outputting the second pulse signal is stored.
For this reason, it becomes easy to change the combination of the 1st pulse signal pattern 13 and the 2nd pulse signal pattern 14, and it can change the combination of the 1st signal and the 2nd signal easily according to measurement distance etc. it can.

In the above embodiment, the phase difference Δθ between the phase of Rx1 and the phase of Rx2 is displaced in the range of 0 to 2π. However, depending on the value of the distance r from the distance measuring unit 4 to the detected device 2 and the frequency difference between the first signal and the second signal, the phase of Rx1 or the phase of Rx2 may go around. In this case, since the phase difference Δθ is displaced in the range of 0 to 2π even if the phase makes one round, the calculation unit 18 recognizes that the phase of Rx1 or the phase of Rx2 has rounded only from the phase difference Δθ. I can't. For this reason, an upper limit value of the distance r to be measured is set in advance, and the frequency difference between the first signal and the second signal is set so that the phase of Rx1 or the phase of Rx2 does not make a round even if the upper limit value is measured. Can be set in advance.
As a result, when measuring the distance r in the range of the upper limit value, the distance r can be measured in a range in which the phase of Rx1 or the phase of Rx2 goes around, and the distance r can be measured only by the phase difference Δθ. .

For example, when the upper limit value of the distance r to be measured is set to 5 m, from the above formulas (5) and (6), when the phase difference Δθ is set to 3 × 10 ⁸ m / s of the electromagnetic wave velocity c, the following formula It is expressed as (7).
Phase difference Δθ = (ω ₂ -ω ₁ ) τ
= 360 × (f ₂ −f ₁ ) × (5 / (3 × 10 ⁸ ))
= (F ₂ −f ₁ ) × 6 × 10 ⁻⁶ (7)

Since the phase difference Δθ is desired to be displaced in the range of 0 to 2π, the range of (f ₂ −f ₁ ) is expressed by the following formula (8).
0 ≦ (f ₂ −f ₁ ) × 6 × 10 ⁻⁶ ≦ 360
0 ≦ (f ₂ −f ₁ ) × 10 ⁻⁶ ≦ 60
0 ≦ (f ₂ −f ₁ ) ≦ 60 × 10 ⁶ (Hz)
... (8)

From the above equation (8), the range of (f ₂ −f ₁ ) is a range of 0 to 60 MHz.
As described above, when the upper limit value of the distance r to be measured is set to 5 m, the phase difference of Rx1 is set if the frequency difference between the frequency f ₁ of the first signal and the frequency f ₂ of the second signal is set to 60 MHz or less. Alternatively, the distance measurement can be performed within a range until the phase of Rx2 goes around.
In this way, if the upper limit value of the distance r to be measured is set, the frequency f ₁ of the first signal and the frequency f _{2 of} the second signal can be appropriately measured for a preset measurement range. A frequency difference can be set.

When the distance r is measured without setting an upper limit value for the distance r to be measured, as described above, the calculation unit 18 recognizes that the phase of Rx1 or the phase of Rx2 has made one round from the phase difference Δθ alone. However, if the attenuation of the received power is considered in addition to the phase difference Δθ, it can be determined whether the phase of Rx1 or the phase of Rx2 has made one round.
This is because the attenuation of the received power has a correlation with the distance r, and it can be determined by the attenuation of the received power whether or not the phase of Rx1 or the phase of Rx2 has made one round.

Returning to FIG. 1, the distance measurement unit 4 gives the detection unit 5 distance information indicating the distance r from the distance measurement unit 4 to the detected device 2, which is obtained by the calculation unit 18.
The detection unit 5 can acquire the distance r from each distance measurement unit 4 to each detected device 2 obtained by each distance measurement unit 4 based on the distance information given from each distance measurement unit 4.
Each distance measuring unit 4 is installed at a different position, and measures the distance from each installation position to the detected device 2. Therefore, the detection unit 5 can detect the position of the detected device 2 based on the installation position of each distance measurement unit 4 and the distance r obtained by each distance measurement unit 4.

As described above, according to the position detection system of the present embodiment, since the position of the detected device 2 can be detected based on the distance r obtained by each distance measuring unit 4, the detected device can be detected from each distance measuring unit. The distance to 2 can be obtained with high accuracy, and the position of the detected device 2 can be detected with high accuracy.

In addition, in the position detection system of this embodiment, although the case where the three distance measurement parts 4 were provided was illustrated, if at least two distance measurement parts 4 were provided, the position of the to-be-detected apparatus 2 will be detected by the detection part 5. Can be detected.
However, in order to detect the position of the device 2 to be detected with higher accuracy, it is preferable that three or more distance measuring units 4 are provided.

The signal output unit 7 of the device to be detected 2 according to the present embodiment outputs the first pulse signal and the second pulse signal from the memory unit 12 storing the first pulse signal pattern 13 and the second pulse signal pattern 14. For example, as illustrated in FIG. 6, when the signal output unit 7 includes a plurality of (two in the illustrated example) first memory unit 12 a and second memory unit 12 b, The first pulse signal pattern 13 is stored in the memory unit 12a, the second pulse signal pattern 14 is stored in the second memory unit 12b, and the first pulse signal and the second pulse signal are output from the separate memory units 12a and 12b. You may comprise as follows.

In this case, however, the control unit 11 has the same phase as the phase of the first pulse signal output from the first memory unit 12a and the phase of the second pulse signal output from the second memory unit 12b. So that the phase is synchronized.

[2 About the second embodiment]
FIG. 7 is a block diagram illustrating a main configuration of the detected device 2 included in the position detection system according to the second embodiment.
In the detected device 2 of the present embodiment, one pulse signal pattern 25 is stored in the memory unit 12, and the pulse signal output from the memory unit 12 based on the pulse signal pattern 25 includes a first signal and a second signal. Both are different from the first embodiment in that both are included. Since other points are the same as those in the first embodiment, description thereof is omitted.

In FIG. 7, the memory unit 12 of the present embodiment stores one pulse signal pattern 25. The pulse signal pattern 25 is obtained by storing a pulse signal generated in advance in the memory unit 12 as a pattern. Therefore, the memory unit 12 can output a pulse signal by outputting a signal according to the pulse signal pattern 25.

The pulse signal is a digital modulation signal obtained by ΔΣ modulation of the first signal and the second signal, and includes both the first signal and the second signal as main signal components.

FIG. 8 is a diagram showing a part of the frequency spectrum of the pulse signal.
As shown in the figure, the pulse signal of the present embodiment includes a first signal having a frequency f ₁ as a main signal component. The pulse signal also includes a _second signal having a frequency f2 as a main signal component.
The pulse signal includes a quantization noise component generated by ΔΣ modulation in a band near the frequency f ₁ and a band other than the band near the frequency f ₂ .

Such a pulse signal is generated using a 2-input ΔΣ modulator having two input ports for receiving a signal to be modulated.
The two-input ΔΣ modulator will be described later.

Returning to FIG. 7, the memory unit 12 stores a pulse signal generated by performing ΔΣ modulation on the first signal and the second signal as a pattern for outputting as a pulse signal.
The memory unit 12 outputs a pulse signal by outputting a signal according to the pulse signal pattern 25 under the control of the control unit 11.
Thus, the signal output unit 7 outputs a pulse signal including both the first signal and the second signal.

The memory unit 12 provides the output pulse signal to each of the first BPF 8 and the second BPF 9.
The 1BPF8, as described above, the pulse signal from the memory unit 12 is provided and passed through the frequency f ₁ of input signal components including a first signal as a pass signal, blocks passage of the signal components of other bands It is configured as follows.
Therefore, the first BPF 8 blocks the passage of the first signal included in the passing signal by blocking the passage of the signal component of the other band including the second signal, the quantization noise component, and the like. To give.

The 2BPF9, as described above, the pulse signal from the memory unit 12 is supplied, passed through a frequency f ₂ near the signal component including the second signal as a pass signal, blocks passage of the signal components of other bands It is configured as follows.
Therefore, the second BPF 9 blocks the passage of the second signal included in the passing signal by blocking the passage of the signal component of the other band including the first signal, the quantization noise component, and the like. To give.

The antenna 10 radiates the first signal and the second signal given from the first BPF 8 and the second BPF 9 to space.
Thereby, the transmission unit 6 of the detected device 2 wirelessly transmits the first signal and the second signal from the antenna 10.
The first signal and the second signal transmitted by the detected device 2 are received by the distance measuring unit 4 (FIG. 5) and used to obtain the distance from the distance measuring unit 4 to the detected device 2 or detected. The unit 5 (FIG. 1) is used to detect the position of the device 2 to be detected.

As described in the first embodiment, the distance measurement unit 4 determines the distance from the distance measurement unit 4 to the detected device 2 based on the phase difference between the phase of the first signal and the phase of the second signal at the time of reception. Ask.
Therefore, if the first signal and the second signal are not accurately phase-synchronized so that they have the same phase at the time of transmission, the distance measuring unit 4 accurately determines the distance from the distance measuring unit 4 to the detected device 2. I can't find it well.
In this regard, in this embodiment, the memory unit 12 stores a pulse signal pattern 25 that is one signal pattern for outputting a pulse signal including both the first signal and the second signal as a signal pattern. The signal output unit 7 outputs a pulse signal including both the first signal and the second signal obtained by ΔΣ modulation of the first signal and the second signal. And the second signal can be surely synchronized with each other in the phase between the first signal and the second signal. Thereby, it is possible to cause the distance measurement unit 4 to accurately obtain the distance from the distance measurement unit 4 to the detected device 2.

[3 2-input ΔΣ modulator in the second embodiment]
FIG. 9 shows a two-input ΔΣ modulator 30 used to generate a pulse signal in the second embodiment.
ΔΣ modulator 30 in FIG. 9, the first input port 31a of the first signal U ₁ is input, single output port for outputting the second input port 31b of the second signal U ₂ is input, and the pulse signal 31c. The ΔΣ modulator 30 includes a plurality of loop filters (a first loop filter 32 and a second loop filter 33) corresponding to each of the plurality of input ports 31a and 31b, an adder 34, and a quantizer 35. Yes.
The plurality of loop filters 32 and 33 are connected to the output side of the quantizer 35 via the first input sections 32a and 33a connected to the corresponding input ports 31a and 31b, respectively, and the feedback paths 36a and 36b. 2nd input part 32b, 33b.

Input signals U ₁ and U ₂ input to the corresponding input ports 31a and 31b are input to the first input units 32a and 33a. The feedback signal V of the output V of the quantizer 35 is input to the second input units 32b and 33b.

The plurality of loop filters 32 and 33 are provided with differentiators 320a and 330a, respectively. Connected to the differentiators 320a and 330a are first paths 320d and 330d connected to the first input sections 32a and 33a and second paths 320e and 330e connected to the second input sections 32b and 33b, respectively. Has been. The differentiators 320a and 330a obtain differences U ₁ -V and U ₂ -V between the input signals U ₁ and U ₂ and the feedback signal V from the quantizer 35, respectively.

Differences U ₁ −V and U ₂ −V obtained by the differentiators 320a and 330a are input to internal filters 320b and 330b provided in the loop filters 32 and 33, respectively. The transfer function of the internal filter 320b of the first loop filter 32 is expressed as L ₁ (z), and the transfer function of the internal filter 330b of the second loop filter 33 is expressed as L ₂ (z).

The outputs L ₁ (z) (U ₁ (z) −V (z)) and L ₂ (z) (U ₂ (z) −V (z)) of the internal filters 320b and 330b are respectively connected to the loop filters 32, 33 is provided to the adders 320 c and 330 c provided in 33.
Feed forward paths 320f and 330f for inputting the input signals U ₁ and U ₂ input to the first input units 32a and 33a to the adders 320c and 330c are connected to the adders 320c and 330c, respectively. Therefore, each adder 320c, 330c receives the input signals U ₁ , U ₂ and the outputs L ₁ (z) (U ₁ (z) −V (z)), L ₂ (z) ( U ₂ (z) −V (z)) is added.

The outputs of the adders 320c and 330c (outputs of the loop filters 32 and 33) Y ₁ and Y ₂ are added by the adder 34.

The output Y of the adder 34 is given to the quantizer 35. The quantizer 35 of the present embodiment is a two-level quantizer and outputs a 1-bit pulse train as a quantized signal (ΔΣ modulation signal) V. This quantized signal V becomes an output signal of the ΔΣ modulator 30. The output signal V is given to the loop filters 32 and 33 via the feedback paths 36a and 36b.

The output V of the ΔΣ modulator 30 in FIG. 9 is expressed by the following equation (9) (when N = 2 in equation (9)). In Equation (9), STF _i (z) is the i-th signal transfer function for the i-th input signal U _i (z), and NTF (z) is the noise transfer function for the entire ΔΣ modulator 30. E (z) is a noise transfer function.

here,

The internal filter 320b of the first loop filter 32 has a transfer function L ₁ (z) expressed using the first noise transfer function NTF ₁ (z). The first noise transfer function NTF ₁ (z) has a characteristic (band stop characteristic) for suppressing quantization noise in a band near the frequency f ₁ of the first signal input to the first loop filter 32.
The internal filter 330b of the second loop filter 33 has a transfer function L ₂ (z) indicated by using the second noise transfer function NTF ₂ (z). The second noise transfer function NTF ₂ (z) has a characteristic (band stop characteristic) for suppressing quantization noise in a band near the frequency f ₂ of the second signal input to the second loop filter 33.

The ΔΣ modulator 30 configured as described above simultaneously converts the first signal input to the first input port 31a and the second signal input to the second input port 31b into one single output signal. It can be included and output in a pulse signal of V (z).
That is, the ΔΣ modulator 30 can generate a pulse signal having a frequency spectrum shown in FIG.

[4 Others]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.
For example, in each of the above embodiments, the case where the detected apparatus 2 includes one antenna 10 and transmits both the first signal and the second signal from the antenna 10 has been described. The first signal may be transmitted from one antenna and the second signal may be transmitted from the other antenna.
Moreover, in each said embodiment, the to-be-detected apparatus 2 outputs the pulse signal pattern memorize | stored in the memory part 12 (1st memory part 12a, 2nd memory part 12b), and a pulse signal (1st pulse signal) The second pulse signal) is output as an example, but the detected device 2 is a pulse signal including either the first signal or the second signal, or a pulse signal including both the first signal and the second signal. There may be provided a ΔΣ modulator for generating. In this case, the detected device 2 can transmit the first signal and the second signal while generating the pulse signal.

In addition, the scope of the present invention is indicated not by the above-described meaning but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

1 position detection system 2 device to be detected (device to be measured)
DESCRIPTION OF SYMBOLS 3 Position detection apparatus 4 Distance measurement part 5 Detection part 6 Transmission part 7 Signal output part 8 1st band pass filter 9 2nd band pass filter 10 Antenna 11 Control part 12 Memory part 12a 1st memory part 12b 2nd memory part 13 1st 1 pulse signal pattern 14 second pulse signal pattern 15 ΔΣ modulator 16 antenna 17 receiving unit 18 calculating unit 19 first phase detecting unit 20 second phase detecting unit 21 adder 22 processing unit 25 pulse signal pattern 30 ΔΣ modulator 31a input Port 31b Input port 31c Output port 32 First loop filter 32a First input unit 32b Second input unit 33 Second loop filter 33a First input unit 33b Second input unit 34 Adder 35 Quantizers 36a and 36b Feedback path 320a , 330a Differentiator 320b, 330b Inside Filter 320c, 330c adder 320d, 330d first path 320 e, 330e second path 320f, 330f feedforward path

Claims (10)

1. A distance measurement system comprising: a device under measurement; and a distance measurement device that obtains a distance to the device under measurement,
   The device under test includes a transmission unit that wirelessly transmits a first signal having a predetermined frequency and a second signal having a frequency different from the first signal in phase synchronization with each other,
   The distance measuring device includes a receiving unit that receives the first signal and the second signal;
   A distance measurement system comprising: an arithmetic unit that obtains a distance from the distance measurement device to the device under measurement based on a phase difference between the received first signal and the second signal.
2. A transmission unit of the device under test, a memory unit storing a signal pattern for outputting a first digital signal including the first signal and a second digital signal including the second signal;
   The first digital signal and the second digital signal based on the signal pattern are acquired from the memory unit, and the first signal included in the first digital signal and the second signal included in the second digital signal. The distance measurement system according to claim 1, further comprising: a control unit that wirelessly transmits the signals in phase synchronization with each other.
3. 3. The distance measuring system according to claim 2, wherein the first digital signal and the second digital signal are pulse signals obtained by performing ΔΣ modulation on the first signal and the second signal.
4. The distance measuring system according to claim 3, wherein the memory unit stores one signal pattern for outputting a pulse signal including both the first signal and the second signal as the signal pattern.
5. The memory unit stores, as the signal pattern, a first signal pattern for outputting a pulse signal including the first signal and a second signal pattern for outputting a pulse signal including the second signal. The distance measuring system according to claim 3.
6. The frequency of the first signal and the frequency of the second signal are set to values at which the first signal and the second signal can be transmitted and received by a single antenna. The distance measuring system according to any one of the above.
7. A distance measuring device for obtaining a distance to a device under test,
   A receiving unit that receives a first signal of a predetermined frequency transmitted wirelessly and a second signal having a frequency different from that of the first signal and synchronized in phase;
   A distance measuring device comprising: a computing unit that obtains a distance from the device itself to the device under measurement based on a phase difference between the received first signal and the second signal.
8. A device under test for causing a distance measuring device to obtain a distance to the distance measuring device,
   A first signal having a predetermined frequency for obtaining a distance from the distance measuring device to the device to be measured based on a mutual phase difference and a second signal having a frequency different from the first signal are wirelessly synchronized in phase. A device under measurement including a transmission unit for transmission.
9. A transmission unit of the device under test, a memory unit storing a signal pattern for outputting a first digital signal including the first signal and a second digital signal including the second signal;
   The first digital signal and the second digital signal based on the signal pattern are acquired from the memory unit, and the first signal included in the first digital signal and the second signal included in the second digital signal. 9. A device under measurement according to claim 8, further comprising: a control unit that wirelessly transmits the signals in phase synchronization with each other.
10. A position detection system comprising: a detected device; and a position detecting device that detects a position of the detected device,
    The detected apparatus includes a transmission unit that wirelessly transmits a first signal having a predetermined frequency and a second signal having a frequency different from the first signal in phase synchronization,
    The position detecting device detects a position of the detected device based on a plurality of distance measuring units and distances from the plurality of distance measuring units obtained by the plurality of distance measuring units to the detected device. With
    The plurality of distance measuring units each receive the first signal and the second signal;
    A position detection system comprising: a calculation unit that obtains a distance from each distance measurement unit to the detected device based on a phase difference between the received first signal and the second signal.

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