JP5117999B2 - Distance measuring device - Google Patents

Description

  The present invention relates to an apparatus for transmitting and receiving a single sine wave between two transmission / reception devices and measuring a distance between the two transmission / reception devices.

As an apparatus for measuring the distance to an object that reflects electromagnetic waves, an apparatus described in Patent Document 1 is known. This device forms a phase-locked loop between a transmission / reception device and a reflection object, and measures the distance from the synchronization frequency at that time.
Further, as in Patent Documents 2 and 3 invented by the present inventor, two transmitting / receiving devices are used as one set, a phase-locked loop is formed between the two transmitting / receiving devices, and several hundreds of square waves of several MHz are generated. There is known an apparatus for detecting a phase delay of a rectangular wave of about several MHz on a high frequency carrier wave of several GHz.
JP2004-198306 JP2008-032535 JP2008-122255A

However, the method disclosed in Patent Document 1 detects a frequency that is synchronized between the transmission signal and the reception signal of the reflected wave, and measures the distance between the transmitter and the reflector from the frequency. Is the method. There is a problem that it is difficult to detect the frequency to be synchronized by sequentially changing the frequency. Further, the methods of Patent Documents 2 and 3 require a wide bandwidth in order to modulate a rectangular wave. When measuring the distance using extremely weak radio waves, it is necessary to increase the sensitivity and receive the radio waves. However, if the sensitivity is improved, interference occurs. Therefore, when receiving extremely weak radio waves, it is desirable that the signal band be a minimum bandwidth in order to suppress interference.
SUMMARY OF THE INVENTION An object of the present invention is to provide a distance measuring device having a simple structure and a narrower use band.

  The invention according to claim 1 comprises a first transmitter / receiver device and a second transmitter / receiver device, and is a distance measuring device for measuring a distance between the first transmitter / receiver device and the second transmitter / receiver device. A first transmission antenna that transmits a signal to the transmission / reception device; a first reception antenna that receives a transmission signal from the second transmission / reception device; a reference oscillator that outputs a signal having a predetermined waveform at a predetermined reference frequency; A first phase comparison that compares the phases of a first frequency converter that inputs a signal received by an antenna and converts the frequency to a reference frequency signal, an output signal of the reference oscillator, and an output signal of the first frequency converter And the voltage-controlled oscillator that changes the phase and frequency of the waveform so that the phase difference compared by the first phase comparator becomes zero, and the frequency of the output signal of the voltage-controlled oscillator, or its output. A transmitter that converts the frequency of the signal to a predetermined frequency and outputs the signal as a single-frequency sine wave signal to the first transmitting antenna; the phase of the output signal of the voltage controlled oscillator; and the phase of the output signal of the reference oscillator And a second phase comparator that outputs a signal corresponding to the phase difference as a distance signal, and the second transmission / reception device receives a signal transmitted from the first transmission / reception device. An antenna, a second transmission antenna that transmits a signal to the first transmission / reception device, and a second frequency converter that converts the frequency of the signal received by the second reception antenna and outputs the signal to the second transmission antenna. It is a distance measuring device characterized by having.

  In the present invention, the transmitting antenna and the receiving antenna are not necessarily independent antennas. For example, by using a circulator or a duplexer, a configuration may be adopted in which one antenna for transmission / reception is provided in each of the first transmission / reception apparatus and / or the second transmission / reception apparatus. The transmitter is a transmitter that amplifies the output signal of the voltage controlled oscillator as it is, or a transmitter that converts the output signal of the voltage controlled oscillator into a predetermined frequency and sends it out. The conversion to the predetermined frequency includes up-conversion and down-conversion. The reference oscillator and the second reference oscillator may be a sine wave oscillator or a rectangular wave oscillator. The voltage controlled oscillator and the second voltage controlled oscillator may be a sine wave oscillator or a rectangular wave oscillator. Furthermore, the multiplier, the second multiplier, the frequency divider, and the second frequency divider may divide a sine wave or divide a rectangular wave. The first phase comparator and the second phase comparator may be sine waves for phase comparison or rectangular waves for phase comparison. In short, in the present invention, a single-frequency sine wave is used as a radio wave for distance measurement. The baseband signal used for phase comparison for distance measurement may be a sine wave or a rectangular wave. Since the cosine wave is only 90 degrees out of phase with the sine wave, the sine wave is a concept including the cosine wave.

  Moreover, you may use a mixer other than a multiplier and a division period for a 1st frequency converter. For example, the first frequency converter includes a multiplier that multiplies the frequency of the output signal of the reference oscillator, or a frequency divider that divides, a reception signal of the first receiving antenna, and an output signal of the multiplier or the frequency divider. It is good also as a structure which has a mixer which calculates | requires the product of these.

  The first frequency converter is a multiplier that multiplies the frequency of the output signal of the voltage controlled oscillator, or a frequency divider that divides, a received signal of the first receiving antenna, and an output of the multiplier or the frequency divider. It is good also as a structure which has a mixer which calculates | requires the product with a signal.

Furthermore, the second frequency converter is a voltage controlled oscillator that generates a signal having the same frequency and the same phase as the received signal by the second receiving antenna, and a multiplier or a frequency divider that multiplies the frequency of the output signal of the voltage controlled oscillator. It is good also as a structure which has a frequency divider.
The second transmitting / receiving apparatus includes a second reference oscillator that oscillates a signal having a predetermined frequency, and the second frequency converter is a second multiplier that multiplies the frequency of the output signal of the second reference oscillator, or a divider. A second mixer for obtaining a product of a second frequency divider, a received signal of the second receiving antenna, and an output signal of the second multiplier or the second divider, and a frequency of the output signal of the second mixer. It is good also as a structure which has the 2nd voltage control oscillator to convert.

  In the present invention, the first transmission / reception device transmits a single-frequency sine wave signal, the second transmission / reception device frequency-converts this signal, and the frequency-converted single-frequency sine wave signal is first transmitted / received. Replying to the device. In the first transmission / reception device, the sine wave signal transmitted from the first transmission / reception device so as to be phase-synchronized between the single-frequency waveform signal and the waveform signal received by the first transmission / reception device. The phase is controlled. The distance between the first transmission / reception device and the second transmission / reception device is measured from the phase difference between the output signal of the voltage controlled oscillator and the output signal of the reference oscillator. Therefore, the frequency of the radio wave used for distance measurement is a single frequency, and the use band is extremely narrow. In addition, since a one-phase PLL is formed between the first transmission / reception device and the second transmission / reception device, the detected phase is stable even when the first transmission / reception device and the second transmission / reception device are moving. Thus, distance measurement between moving bodies can be stably obtained.

  Hereinafter, specific embodiments of the present invention will be described with reference to block diagrams. As each component described in the block diagram, any available component can be used as long as it has a necessary action. Of course, it is within the scope of the present invention to replace each component or add another component without departing from the spirit of the present invention. In the configuration of the following embodiment, for convenience of explanation, only the configuration in which the first transmission / reception device and the second transmission / reception device have two independent transmission antennas and reception antennas is shown. However, in the implementation of the present invention, the transmission antenna and the reception antenna are not necessarily independent antennas. For example, by using a circulator or a duplexer, a configuration may be adopted in which one antenna for transmission / reception is provided in each of the first transmission / reception apparatus and / or the second transmission / reception apparatus.

  FIG. 1 is a block diagram showing a specific configuration of a first transmission / reception device 100 and a second transmission / reception device 200 according to a specific embodiment of the present invention.

  1 includes a reference oscillator 10 that oscillates a sine wave that is a reference signal having a single reference frequency f, a first reception antenna 20 that receives a transmission signal from the second transmission / reception device 200, and An amplifier 19 that amplifies the received signal, a first frequency converter 12 that converts the output signal of the amplifier into a single frequency sine wave of the reference signal, and a phase of the sine wave of the reference signal output from the reference oscillator 10 And a first phase comparator 11 that compares the phase of the sine wave output from the first frequency converter 12. The first transmission / reception device 100 includes a loop filter 13 that integrates the phase difference signal output from the first phase comparator 11, and a voltage-controlled oscillator 14 that changes the oscillation frequency according to the output voltage of the loop filter 13. It has an amplifier 15 for amplifying the output signal, and a first transmission antenna 18 for transmitting the output signal. Further, a second phase comparator 16 that compares the phase of the sine wave of the reference signal output from the reference oscillator 10 with the phase of the sine wave output from the voltage controlled oscillator 14, and a low-pass filter 17 that integrates the output thereof. Have.

  The second transmission / reception device 200 includes a second reception antenna 51 that receives a signal transmitted from the first transmission / reception device 100, and a second frequency converter 50 that converts the frequency of the signal received by the second reception antenna 51. is doing. In the first embodiment, the first frequency converter 12 is a 1/10 frequency divider, and the second frequency converter 50 is a 10 × multiplier.

  Next, the operation of this apparatus will be described. In the present embodiment, the reference signal output from the reference oscillator 10 is a sine wave having a frequency of 10 MHz. The signal output from the voltage controlled oscillator 14 is also a sine wave having a frequency of 10 MHz. In the second transmitting / receiving device 200, the received 10 MHz sine wave is frequency-converted into a 100 MHz sine wave and transmitted from the second transmitting antenna.

とする。ただし、０≦θ₁ ＜２πである。
また、電圧制御発振器１４の出力信号を

とする。ただし、０≦θ₂ ＜２πである。 The output signal of the reference oscillator 10

And However, 0 ≦ θ ₁ <2π.
The output signal of the voltage controlled oscillator 14 is

And However, 0 ≦ θ ₂ <2π.

となる。
ただし、ｎ₁ は、位相を主値（０以上、２πより小さい値）とするため値である。すなわち、ｎ₁ は、０≦θ₂ −ωΔｔ−２ｎ₁π＜２πを満たす整数である。 If the propagation delay time between the first transmitting antenna 18 and the second receiving antenna 51 is Δt, the signal received by the second receiving antenna 51 is

It becomes.
However, n ₁ is a value for setting the phase to a main value (a value greater than or equal to 0 and less than 2π). That is, n ₁ is an integer that satisfies 0 ≦ θ ₂ −ωΔt−2n ₁ π <2π.

となる。
ただし、ｎ₃ は、位相を主値とするための値である。すなわち、ｎ₃ は、０≦Ｎθ₂ −ＮωΔｔ−２ｎ₃π＜２πを満たす整数である。 Then, the output signal of the second frequency converter 50, that is, the signal transmitted from the second transmitting antenna 52 is

It becomes.
However, n ₃ is a value for setting the phase as a main value. That is, n ₃ is an integer that satisfies 0 ≦ Nθ ₂ −NωΔt−2n ₃ π <2π.

となる。ただし、ｎ₄ は、位相を主値とする値である。すなわち、ｎ₄ は、０≦Ｎθ₂ −２ＮωΔｔ−２ｎ₄π＜２πを満たす整数である。 Next, since the reception signal of the first receiving antenna 20 has a propagation delay time Δt between the second transmitting antenna 52 and the first receiving antenna 20,

It becomes. Here, n ₄ is a value whose phase is the main value. That is, n ₄ is an integer that satisfies 0 ≦ Nθ ₂ −2NωΔt−2n ₄ π <2π.

となる。
ただし、ｍ＝０，１，２，…Ｎである。２ｍπ／Ｎは、第１周波数変換器１２の分周による不確定位相差である。また、ｋは、０≦θ₂ −２ωΔｔ−２ｎ₄π／Ｎ−２ｍπ／Ｎ−２ｋπ＜２πを、満たす、整数である。不確定位相差２ｍπ／Ｎは、元の正弦波の零点と、分周周波数の制限波との位相関係で決定される値であって、分周器の分周タイミングによって、偶然的に決定される値である。２ｍπ／Ｎは、分周器による遅れ位相と見ることができる。 Next, the signal frequency-converted to 1 / N by the first frequency converter 12 is

It becomes.
However, m = 0, 1, 2,... N. 2mπ / N is an uncertain phase difference due to the frequency division of the first frequency converter 12. K is an integer satisfying 0 ≦ θ ₂ −2ωΔt−2n ₄ π / N−2mπ / N−2kπ <2π. The indeterminate phase difference 2mπ / N is a value determined by the phase relationship between the zero point of the original sine wave and the limit wave of the frequency division frequency, and is determined by chance depending on the frequency division timing of the frequency divider. Value. 2mπ / N can be regarded as a delayed phase due to the frequency divider.

すなわち、電圧制御発振器１４の出力信号は、

となる。＋２ｍπ／Ｎは、第１周波数変換器１２による分周位相遅れを補償するために、遅れ位相と等量だけ、位相を進めることで、第１位相比較器１１により比較される２つの位相差は、零となる。 The voltage controlled oscillator 14 determines the frequency and the phase θ ₂ so that the phase difference compared by the first phase comparator 11 becomes zero. Therefore,

That is, the output signal of the voltage controlled oscillator 14 is

It becomes. + 2mπ / N is the same as the delayed phase in order to compensate the divided phase lag by the first frequency converter 12, so that the two phase differences compared by the first phase comparator 11 are It becomes zero.

In this way, in this apparatus, the phase 2ωΔt corresponding to the round-trip propagation delay time 2Δt between the first transmission / reception apparatus 100 and the second transmission / reception apparatus 200 is (2n _{4) with} respect to the phase θ _{1 of the} reference signal. The phase is advanced by a value obtained by adding (π / N + 2mπ / N + 2kπ) and transmitted from the first transmitting antenna 18. As a result, the output signal of the first frequency converter 12 becomes sin (ωt + θ ₁ ), and its phase coincides with the phase θ _{1 of the} reference signal. Thus, the feedback of the frequency and the phase is applied so that the phase difference output from the first phase comparator 11 becomes zero, and one round formed between the first transmission / reception device 100 and the second transmission / reception device 200. The PLL will be stable.

となる。
ただし、ｉ、ｊは、Δθを、主知とするための整数で、ｉは、０≦θ₂ −θ₁ −２ｉπ＜０を満たす整数、ｊは、０≦２ωΔｔ＋２ｎ₄π／Ｎ＋２ｍπ／Ｎ＋２ｊπ＜０を満たす整数である。また、ｐは整数で、ｐ＝ｎ₄ ＋ｍ＋Ｎｊである。この時、０≦Δθ＜２πとすることができる。
ただし、距離の測定可能範囲は、次のように制限される。第１送受信装置１００の受信信号を表す（５）式から、２ＮωΔｔに、２ｍπを加算した時の正弦波の値は、変化がないので、判別し得るΔｔの範囲は、次式で表される。

The phase difference Δθ output from the second phase comparator 16 is

It becomes.
Here, i and j are integers for making Δθ the main knowledge, i is an integer satisfying 0 ≦ θ ₂ −θ ₁ −2iπ <0, and j is 0 ≦ 2ωΔt + 2n ₄ π / N + 2mπ / N + 2jπ < It is an integer that satisfies 0. P is an integer, and p = n ₄ + m + Nj. At this time, 0 ≦ Δθ <2π can be satisfied.
However, the measurable range of distance is limited as follows. Since the value of the sine wave when 2mπ is added to 2NωΔt does not change from the equation (5) representing the received signal of the first transmission / reception device 100, the range of Δt that can be discriminated is expressed by the following equation. .

ただし、ｃは、光速である。 Therefore, the measurable distance (one way) L is expressed by the following equation.

Where c is the speed of light.

よって、第１送受信装置１００と第２送受信装置２００との間の距離（片道）Ｌは、次式で求められる。

Then, the propagation delay time (one way) Δt is obtained from the equation (9) using the detected phase difference Δθ as follows.

Therefore, the distance (one way) L between the first transmission / reception device 100 and the second transmission / reception device 200 is obtained by the following equation.

  In this way, the detection phase difference Δθ can be measured, and the distance L can be measured using equation (13). In this case, the distance cΔθ / (2ω) obtained from the detected phase difference Δθ is corrected by cpπ / (Nω) so that the distance L exists in the absolute distance measurable range of the equation (11). That is, when the distance cΔθ / (2ω) obtained from the detected phase difference Δθ exceeds the absolute distance measurable range of the equation (11), cpπ / (Nω) is subtracted and the distance can be measured absolutely. The integer p will be determined so that it exists in the range. That is, when it is known in advance that the measurement distance is in the range of the expression (11), the distance in the range, that is, the absolute distance can be measured from the determined p. In other words, the true measured value Δθ corresponding to the distance L must be a value greater than or equal to 0 and less than 2π / N. Therefore, after correcting the corrected measurement value Δθ ′ by Δθ ′ = Δθ + pπ / (Nω) so that 0 ≦ Δθ ′ <2π / N, the true delay time Δt is calculated from the corrected measurement value Δθ ′. Will be asked.

  In the present invention, since the electromagnetic wave propagating through the space has a single frequency of 10 MHz and 100 NHz, the use bandwidth is extremely narrow. Further, since only frequency conversion is performed using only a single frequency, the circuit configuration becomes extremely simple.

  In this way, the absolute distance between the first transmission / reception device and the second transmission / reception device can be measured. In the above example, a round trip distance of 3 m wavelength corresponding to 100 MHz (1.5 m between devices) can be measured.

  Further, if the second transmission / reception device 200 transmits the signal as it is to the first transmission / reception device 100 at 10 MHz without frequency conversion, the measurable absolute distance range is 30 m in the round-trip distance.

  Further, the first transmission / reception device tunes the frequency of the received signal by changing the conversion frequency of the second frequency converter 50 of the second transmission / reception device 200 to a unique value for each second transmission / reception device 200. Thus, the distance from each second transmission / reception device 200 can be measured.

In the second embodiment, the first frequency converter 12 of the first transmission / reception device 100 according to the first embodiment is configured by a multiplier and a mixer. Other configurations are the same as those in FIG.
As shown in FIG. 2, the first frequency converter 12 includes a multiplier 121 that multiplies the frequency of the reference signal output from the reference oscillator 10, a mixer that mixes the output signal of the multiplier 121 and the received signal. 120 and a band pass filter 122 that extracts only the lower band from the output of the mixer 120.

となる。
ただし、ｎ₅ は、位相を主値とするための値である。すなわち、ｎ₅ は、０≦Ｍθ₁ −２ｎ₅π＜２πを満たす整数である。 The output signal of the multiplier 121 is

It becomes.
However, n ₅ is a value for the phase as principal value. That is, n ₅ is an integer that satisfies 0 ≦ Mθ ₁ −2n ₅ π <2π.

である。ただし、Ｎ−Ｍ＝１である。ｎ₆ 、ｎ₇ は、位相を主値とするための値である。すなわち、ｎ₇ は、ｎ₇ ＝ｎ₆ −ｎ₅ で、０≦Ｎθ₂ −（Ｎ−１）θ₁ −２ＮωΔｔ−２ｎ₇π＜２πを満たす整数である。 Therefore, the output of the band pass filter 122 and the input signal of the first phase comparator 11 is

It is. However, NM = 1. n ₆ and n ₇ are values for setting the phase as a main value. That is, n ₇ is an integer that satisfies n ₇ = n ₆ −n ₅ and satisfies 0 ≦ Nθ ₂ − (N−1) θ ₁ −2NωΔt−2n ₇ π <2π.

となり、（７）式と同一となる。したがって、距離Ｌが、（１１）式の絶対距離測定可能範囲に存在するように、検出位相差Δθから求められる距離ｃΔθ／（２ω）を、ｃｎ₇π／（Ｎω）だけ補正する。すなわち、検出位相差Δθから求められる距離ｃΔθ／（２ω）が、（１１）式の最大値ｃπ／（Ｎω）を越える場合には、ｃｎ₇π／（Ｎω）を減算して、距離が、その絶対測定可能範囲に存在するように、整数ｎ₇ を決定することになる。すなわち、測定距離が、（１１）式の範囲であることが、予め分かっている場合には、決定された、ｎ₇ から、その範囲の距離、すなわち、絶対距離が測定できる。同様に、補正された測定値Δθ’が、０≦Δθ’＜２π／Ｎとなるように、Δθ’＝Δθ＋ｎ₇ π／（Ｎω）で補正した上で、補正測定値Δθ’から真の遅延時間Δｔを求めても良い。本実施例においても、第２周波数変換器５０の変換周波数を第２送受信装置２００毎に変化させ、第１周波数変換装置１２の逓倍器１２１のＭを可変設定して、ダウンコンバートする周波数を可変設定するようにすれば、第１送受信装置１００は、各第２送受信装置からだけの信号をチューニングすることができる。 Since the oscillation frequency and phase of the voltage controlled oscillator 14 are determined so that the phase difference output from the first phase comparator 11 becomes zero,

And is the same as equation (7). Therefore, the distance cΔθ / (2ω) obtained from the detected phase difference Δθ is corrected by cn ₇ π / (Nω) so that the distance L exists in the absolute distance measurable range of the equation (11). That is, when the distance cΔθ / (2ω) obtained from the detected phase difference Δθ exceeds the maximum value cπ / (Nω) of the equation (11), cn ₇ π / (Nω) is subtracted, and the distance becomes The integer n ₇ is determined so as to be within the absolute measurable range. That is, when it is known in advance that the measurement distance is in the range of the expression (11), the distance in the range, that is, the absolute distance can be measured from the determined n ₇ . Similarly, the corrected measured value Δθ ′ is corrected by Δθ ′ = Δθ + n ₇ π / (Nω) so that 0 ≦ Δθ ′ <2π / N, and then the true delay from the corrected measured value Δθ ′. The time Δt may be obtained. Also in the present embodiment, the conversion frequency of the second frequency converter 50 is changed for each second transmission / reception device 200, M of the multiplier 121 of the first frequency conversion device 12 is variably set, and the frequency to be down-converted is variable. If it sets, the 1st transmission / reception apparatus 100 can tune the signal only from each 2nd transmission / reception apparatus.

となる。
ただし、ｎ₈ は、位相を主値とするための値である。すなわち、ｎ₈ は、０≦Ｍθ₂ −２ｎ₈π＜２πを満たす整数である。 The third embodiment is different from the second embodiment in that the input signal to the multiplier 121 is the output signal of the voltage controlled oscillator 14.
Then, the output signal of the multiplier 121 is

It becomes.
However, n ₈ is a value for the phase as principal value. That is, n ₈ is an integer that satisfies 0 ≦ Mθ ₂ −2n ₈ π <2π.

である。ただし、Ｎ−Ｍ＝１である。ｎ₁₀は、位相を主値とするための値である。すなわち、ｎ₁₀は、０≦θ₂ −２ＮωΔｔ−２ｎ₁₀π＜２πを満たす整数である。 Therefore, the output of the band pass filter 122 and the input signal of the first phase comparator 11 is

It is. However, NM = 1. n ₁₀ is a value for setting the phase as a main value. That is, n ₁₀ is an integer that satisfies 0 ≦ θ ₂ −2NωΔt−2n ₁₀ π <2π.

Since the oscillation frequency and phase of the voltage controlled oscillator 14 are determined so that the phase difference output from the first phase comparator 11 becomes zero,

となる。ただし、ｑは、Δθを主値とする整数である。すなわち、０≦２ωＮΔｔ＋２ｑπ＜２πを満たす整数である。
ただし、（１０）式より明らかなように、Δｔのとり得る範囲は、０≦Δｔ＜π／（Ｎω）であるので、０≦２ωＮΔｔ＜２πとなる、すなわち、ｑ＝０である。
本実施例３の場合には、第２位相比較器１６の出力する値は、測定距離範囲が、（１１）式の０≦Ｌ＜ｃπ／（Ｎω）に存在することを前提にして、その出力値を補正することなく、距離Ｌに対応した値となる。
本実施例においても、第２周波数変換器５０の変換周波数を第２送受信装置２００毎に変化させ、第１周波数変換装置１２の逓倍器１２１のＭを可変設定して、ダウンコンバートする周波数を可変設定するようにすれば、第１送受信装置１００は、各第２送受信装置からだけの信号をチューニングすることができる。 Therefore, the phase difference Δθ output from the second phase comparator 16 is

It becomes. However, q is an integer whose main value is Δθ. That is, it is an integer satisfying 0 ≦ 2ωNΔt + 2qπ <2π.
However, as is clear from the equation (10), the range that Δt can take is 0 ≦ Δt <π / (Nω), and therefore 0 ≦ 2ωNΔt <2π, that is, q = 0.
In the case of the third embodiment, the value output from the second phase comparator 16 is based on the assumption that the measurement distance range is 0 ≦ L <cπ / (Nω) in the equation (11). It becomes a value corresponding to the distance L without correcting the output value.
Also in the present embodiment, the conversion frequency of the second frequency converter 50 is changed for each second transmission / reception device 200, M of the multiplier 121 of the first frequency conversion device 12 is variably set, and the frequency to be down-converted is variable. If it sets, the 1st transmission / reception apparatus 100 can tune the signal only from each 2nd transmission / reception apparatus.

In all the embodiments described above, the second transmitting / receiving apparatus 200 can be configured as follows.
As shown in FIG. 4, an amplifier 501 connected to the second receiving antenna 51, a band-pass filter 502 that extracts a single sine wave from its output, a voltage-controlled oscillator 505 that oscillates a reference signal from a sine wave of frequency f, In order to change the frequency and phase of the reference signal by integrating the phase comparator 503 that compares the phase of the reference signal with the phase of the signal output from the band pass filter 502 and the phase difference signal output from the phase comparator 503 Has a loop filter 504 for outputting the command voltage. Further, a multiplier 506 that multiplies the frequency of the output signal of the reference signal oscillator 404 by N times, a band-pass filter 507 that extracts a single frequency from the output, and an amplifier 508 that outputs a signal to the second transmitting antenna 52 are provided. Yes.

  According to this circuit configuration, due to the action of the phase comparator 503, the signal received by the second receiving antenna 51 and the output signal of the voltage controlled oscillator 505 have the same frequency and the same phase. Next, the output signal of the voltage controlled oscillator 505 is multiplied by N times the frequency by a multiplier 506. Therefore, this is the same as the above-described operation analysis, and distance measurement is possible even with the present embodiment.

  In all the embodiments described above, the second frequency conversion device 50 of the second transmission / reception device 200 is configured to reduce the frequency to 1 / N, and the first frequency conversion device 12 of the first transmission / reception device 100 is configured as a frequency. May be configured by a device that converts N times. For example, the frequency of the reference signal may be 10 MHz, N may be 2, that is, the second transmission / reception device 200 may convert the signal to a 5 MHz signal, and the 5 MHz signal may be transmitted to the first transmission / reception device 100. Then, the first transmission / reception device 100 converts the received 5 MHz signal to 10 MHz, which is twice, and compares the phase of the reference signal. In this case, the same analysis as that described above is established. In this case, it is possible to measure a reciprocating distance within 60 m which is a wavelength of 5 MHz.

FIG. 5 shows an apparatus configuration of the present embodiment.
The first transmission / reception device 100 differs from the above-described embodiments in the following points. The reference frequency f of the reference signal oscillator 10 was 2.5 MHz. Further, a multiplier 141 that multiplies the frequency of the output signal of the voltage controlled oscillator 14 by M is used. Moreover, the frequency divider 125 which makes the frequency 1 / N the 1st frequency converter 12 was used. The second transmission / reception device 200 has the same configuration as that of the fourth embodiment. However, in this embodiment, a 1 / N fractional period 510 is used instead of the multiplier 506. In this embodiment, N = 2. The above example and this example differ only in the frequency multiplication and frequency division relations, so the above analysis is valid as it is. Therefore, in this embodiment, a distance within a reciprocating distance of 60 m can be measured.

In this embodiment, a heterodyne detection method is employed. The configuration is shown in FIG. In the first transmission / reception device 100, an amplifier 601 and a band pass filter 602 are connected to the first transmission antenna 18. A signal of frequency ω oscillated by the voltage controlled oscillator 603 is converted into a sine wave of frequency N ₁ ω by an N ₁ times multiplier 604. The signal having the frequency N ₁ ω and the signal having the frequency ω are input to the mixer 605, and the signal having the frequency (N ₁ +1) ω is output to the band pass filter 602. Here, N ₁ = 10 and ω / 2π is 10 MHz. Therefore, the frequency of the transmission signal is 110 MHz.

On the other hand, the signal received by the first receiving antenna 20 is amplified by the amplifier 621 and then input to the mixer 622. Further, the output signal of the voltage controlled oscillator 623 is input to the mixer 622. The output signal of the voltage controlled oscillator 623 is divided into 1 / N ₃ by the dividing period 624, and the phase is compared with the output of the divider 626 by the phase comparator 625. The phase difference is integrated by the loop filter 627, and the frequency and phase of the voltage controlled oscillator 623 are controlled. The output of the mixer 622 is input to the band pass filter 628, amplified by the amplifier 629, and then input to the phase comparator 630. The phase difference output from the phase comparator 630 is integrated by the loop filter 631 and input to the voltage controlled oscillator 632 to control the oscillation frequency and phase.

Now, assuming that the signal received by the first receiving antenna 20 is a sine wave having a frequency of 315 MHz, the frequency of the output signal of the voltage controlled oscillator 623 is 305 MHz, and the output signal of the mixer 622 is a sine wave having a frequency of 10 MHz. . The frequency and phase of the output signal of the voltage controlled oscillator 632 are controlled so that the phase coincides with the frequency of the 10 MHz sine wave. The output signal of the voltage controlled oscillator 632 is divided by ½ by the frequency divider 626, and the output signal becomes a sine wave having a frequency of 5 MHz. The output signal of the voltage controlled oscillator 623 is frequency-divided by 1 / N ₃ by the frequency divider 624 and input to the phase comparator 625. In this case, N ₃ is 61. Accordingly, the output of the frequency divider 624 is a sine wave having a frequency of 5 MHz, and the frequency and phase of the output signal of the voltage controlled oscillator 623 are controlled so that the phase difference output from the phase comparator 625 becomes zero.

Eventually, the mixer 622 has a function of down-converting the received signal to 2 / (N ₃ +2) in synchronization with the received signal by controlling the frequency and phase by the PLL. A signal output from the voltage controlled oscillator 632 equal to the frequency of the signal obtained by down-converting the signal received by the antenna 20 to 2 / (N ₃ +2) is input to the phase comparator 606. A signal from the reference signal oscillator 101 is input to the phase comparator 606.

The reference oscillation signal of the reference signal oscillator 101 is a 10 MHz sine wave. The phase comparator 606 compares the frequency and phase of the signal down-converted to 2 / (N ₃ +2) and the reference signal, and the output is integrated by the loop filter 607 so that the phase difference is zero. Thus, the frequency and phase of the voltage controlled oscillator 603 are controlled. Therefore, the voltage-controlled oscillator 603 outputs the phase θ _{1 of the} reference signal output from the reference signal oscillator 101 and the phase θ _{2 of the} received signal down-converted to 2 / (N ₃ +2). The phase of the signal is determined. That is, the output signal of the pressure controlled oscillator 603 is frequency-converted, transmitted from the first transmitting antenna 18, turned back by the second transmitting / receiving device 200, and the received signal received by the first receiving antenna 20 is 2 The phase of the signal of the voltage controlled oscillator 603 is advanced by the amount of delay phase until it is down-converted to / (N ₃ +2) and input to the phase comparator 606.

The second transmission / reception device 200 is a device that down-converts the signal to a reference frequency signal, up-converts the signal to a predetermined frequency, and transmits the signal from the second transmission antenna 52. The signal received by the second receiving antenna 51 is input to the mixer 651, and the output is input to the phase comparator 652. In addition, a demodulating carrier wave is input to the mixer 651. The phase comparator 652 receives a signal output from the voltage controlled oscillator 653 and compares the phase of the signal with the received signal. The output of the phase comparator 652 is integrated by the loop filter 654, and the frequency and phase of the oscillation signal of the voltage controlled oscillator 653 are controlled so that the phase difference between the two signals input to the phase comparator 652 becomes zero. The The output signal of the voltage controlled oscillator 653, a multiplier 655, being multiplied to N ₁ times the frequency, and inputs to the mixer 651. Here, N ₁ = 10. Therefore, the 110 MHz reception signal is converted into a 10 MHz signal by the output signal of the voltage controlled oscillator 653. That is, the mixer has a function of dividing the received signal by 1 / (N ₁ +1). The output signal of the voltage controlled oscillator 653 is input to the frequency divider 656, divided by ½, to a frequency of 5 MHz, and input to the phase comparator 657. In the phase comparator 657, the transmission signal transmitted from the second transmission antenna 52 is divided by the frequency divider 658 into 1 / N ₂ . Here, N ₂ = 63. Then, the output of the phase comparator 657 is integrated by the loop filter 659 and becomes the control voltage of the voltage controlled oscillator 660. Therefore, the frequency and phase of the oscillation signal of the voltage controlled oscillator 660 are controlled so that the phase difference between the two input signals input to the phase comparator 657 becomes zero. In this case, the frequency of the transmission signal transmitted from the second transmission antenna 52 is 315 MHz.

In this way, the second transmission / reception device 200 is transmitted to the first transmission / reception device 100 after being converted into a desired frequency in synchronization with the received signal. By changing the frequency division ratio N ₂ of the frequency divider 658, the frequency of the transmission signal returned from the second transmission / reception device 200 can be changed for each second transmission / reception device 200. Further, in the first transmission / reception device 100, the received signal can be tuned for each second transmission / reception device 200 by changing the frequency division ratio N ₃ of the frequency divider 624.

  In the first transmission / reception device 100, the distance is obtained from the reference signal output from the reference signal oscillator 101 and the phase difference Δθ output from the phase comparator 161 that receives the signal output from the voltage controlled oscillator 603. In the above case, the phase difference Δθ represents the round trip distance L from the second transmission / reception device 200 to the first transmission / reception device 100 at a distance from the transmission signal having a frequency of 315 MHz to a wavelength of 0.95 m.

Next, the waveform at each point of the circuit of FIG. 6 is analyzed.
The angular frequency of the transmission signal from the first transmission / reception device 100 to the second transmission / reception device is ω ₃ , the propagation time is Δt ₁ , the angular frequency of the transmission signal from the second transmission / reception device 200 to the first transmission / reception device is ω ₄ , and propagation Let time be Δt ₂ . Further, the angular frequency of the demodulated carrier wave of the second transmitting / receiving device 200 is ω ₂ , the angular frequency of the demodulated carrier wave of the first transmitting / receiving device 100 is ω ₅ , the angular frequency of the reference oscillation signal output from the reference signal oscillator 101 is ω ₁ , and the phase. Is θ ₁ . Further, the multiplication ratio of the multipliers 655 and 604 is N ₁ , the frequency division ratio of the frequency divider 658 is N ₂ , and the frequency division ratio of the frequency divider 624 is N ₃ . The phase of the output signal (p ₁ point) of the voltage controlled oscillator 603 is θ, and the phase of the demodulated signal compared by the phase comparator 606 is θ ₂ .

p2点信号( ミキサー６０５の出力）

位相は、０以上、２πより小さい範囲（主値）で定義される必要がある。n ₁ は、位相を主値とするための変数であって、n₁ は、0 ≦N ₁ θ−2n₁π<2πを満たす整数である。p3点信号( 送信点)

p4 点信号( 第２送受信装置２００の受信点)

p5点信号( 復調搬送波)

p6点信号(BPF出力)

The signal at each point in FIG. 6 is as follows.
p1 point signal

p2 point signal (output of mixer 605)

The phase needs to be defined within a range (main value) of 0 or more and less than 2π. n ₁ is a variable for setting the phase as a main value, and n ₁ is an integer satisfying 0 ≦ N ₁ θ−2n ₁ π <2π. p3 point signal (transmission point)

p4 point signal (reception point of second transceiver 200)

p5-point signal (demodulated carrier wave)

p6 point signal (BPF output)

p7点( 第２送受信装置２００のベースバンド復調信号) 信号

2n₅π/(N₁ +1) は、第２送受信装置２００でのダウンコンバートにより発生する不確定位相である。 By phase synchronization at the main value in the phase comparator 652

p7 point (baseband demodulated signal of second transceiver 200) Signal

2n ₅ π / (N ₁ +1) is an indeterminate phase generated by down-conversion in the second transceiver 200.

n₆πは、1/2 分周器により発生する不確定位相である。
p10 点( 第２送受信装置２００の送信点)

p9点(1/N₂ 分周器６５８の出力点)

2n₇π/N₂ は、1/N₂ 分周器により発生する不確定位相である。 p8 points (output point of 1 / 2-minute periodator 656)

n ₆ π is an indeterminate phase generated by the 1/2 divider.
p10 points (transmission point of second transceiver 200)

p9 point (output point of 1 / N ₂ divider 658)

2n ₇ π / N ₂ is an indeterminate phase generated by the 1 / N ₂ frequency divider.

よって、

p10 点( 第２送受信装置２００の送信点) の信号

p12 点( 第１送受信装置１００の受信点) 信号

p13 点の信号( 第１送受信装置１００の復調搬送波)

p14 点(BPF出力) 信号及びp15 点

Phase matching condition at the main value of the signal at points p8 and p9 (phase comparator 657)

Therefore,

Signal at p10 point (transmission point of second transceiver 200)

p12 point (receiving point of first transmitting / receiving device 100) Signal

p13 point signal (demodulated carrier wave of first transmitter / receiver 100)

p14 point (BPF output) signal and p15 point

n₉ πは、1/2 分周器６２６により発生する不確定位相である。
p17 点(1/N₃ 分周器６２４の出力)

2n₁₀π/N₃ は、1/N ₃ 分周により発生する不確定位相である。
p17 点とp16 点（位相比較器６２５）での主値での位相整合条件により、次式が成立する。 Therefore, the phase θ ₂ of the baseband demodulated signal is
p16 points (1/2 divider output)

n ₉ π is an indeterminate phase generated by the 1/2 frequency divider 626.
p17 point (output of 1 / N ₃ divider 624)

2n ₁₀ π / N ₃ is an indeterminate phase generated by 1 / N ₃ frequency division.
The following equation is established according to the phase matching condition at the principal value at the points p17 and p16 (phase comparator 625).

よって、θ₆ は、次式となる。

よって、p14 点(BPF出力) 信号及びp15 点の信号は、次式となる。

Therefore, θ ₆ is as follows.

Therefore, the signal at point p14 (BPF output) and the signal at point p15 are as follows.

0 ≦θ₂ <2πである。 Therefore, θ ₂ is represented by the following equation.

0 ≦ θ ₂ <2π.

2n₅π/(N₁ +1) は、第２送受信装置２００におけるダウンコンバートにより発生する不確定位相である。
4n₈π/N₂ は第１送受信装置１００におけるダウンコンバートにより発生する不確定位相である。
4n₁₀π/N₂ は第２送受信装置１００の1/N₃ 分周により発生する不確定位相である。
4n₈π/N₂ ＋4n₁₀π/N₂ ＝４ｍπ／/N₂ であるので、ダウンコンバーと、１／２分周とを併せて、４ｍπ／/N₂ が、第１送受信装置１００のダウンコンバートにより発生する不確定位相である。
2n₉πN₃ /N₂は第１送受信装置１００の1/2 分周により発生する不確定位相である。
2n₆πは、第２送受信装置２００の1/2 分周により発生する不確定性であるが、2 πの整数倍により、消去される。すなわち、θ₂ は、第２送受信装置２００の1/2 分周により発生した不確定位相の周波数の2 倍の周波数での位相であるので、2 πの整数倍となり、この不確定位相は消去される。 The distance is determined from the phase difference Δθ = θ-θ _2.

2n ₅ π / (N ₁ +1) is an indeterminate phase generated by down-conversion in the second transmission / reception device 200.
4n ₈ π / N ₂ is an indeterminate phase generated by down-conversion in the first transmission / reception device 100.
4n ₁₀ π / N ₂ is an indeterminate phase generated by 1 / N ₃ frequency division of the second transceiver 100.
Because it is _{4n 8 π / N 2 + 4n} 10 π / N 2 = 4mπ // N 2, and down-conversion, together with peripheral 1/2 minutes, 4mπ // N ₂ is the first transceiver 100 down This is an indeterminate phase generated by conversion.
2n ₉ πN ₃ / N ₂ is an indeterminate phase generated by 1/2 frequency division of the first transmitting / receiving device 100.
2n ₆ π is an uncertainty generated by the 1/2 frequency division of the second transmission / reception device 200, but is erased by an integral multiple of 2 π. That is, θ ₂ is an integer multiple of 2π because θ ₂ is a phase at a frequency twice the frequency of the indeterminate phase generated by the 1/2 frequency division of the second transmitting / receiving device 200, and this indeterminate phase is eliminated. Is done.

Thus, since there are three independent uncertain phases in the apparatus of the seventh embodiment, the phase difference Δθ does not represent the distance even within the wavelength λ ₄ range. Therefore, in the present embodiment, the movement distance when the second transmission / reception device 200 is moved in a state in which a loop of PLL is applied between the first transmission / reception device 100 and the second transmission / reception device 200, that is, the relative distance. Can be requested. In the case of the relative distance, Δθ is accumulated, so that the measurable range of the relative distance is not limited.

  In the above embodiment, the absolute distance possible range is limited in accordance with the frequency of the spatial radio wave. Therefore, in all the embodiments described above, the distance can be measured without limiting the range by doing the following. First, the detected phase difference Δθ when PLL synchronization is established between the first transmission / reception device 100 and the second transmission / reception device 200 is stored as an initial value. At this time, the distance L1 between the first transmission / reception device 100 and the second transmission / reception device 200 is measured by another means. In addition, the second transmitter / receiver 200 measures the initial value of the detected phase difference Δθ within the above absolute distance range with respect to the first transmitter / receiver 100 to obtain the initial distance L1. Next, the second transmission / reception device 200 is moved while maintaining the PLL synchronization, and the detection phase Δθ is measured. The detected phase difference Δθ is a periodic function of the distance L. By accumulating the detected phase difference Δθ, the relative movement distance of the second transmitting / receiving device 200 with respect to the first transmitting / receiving device 100 can be measured. In this state, the relative movement speed can be obtained by measuring the relative movement distance and the movement time of the second transmission / reception apparatus 200 with respect to the first transmission / reception apparatus 100. If the transmission line is used instead of the spatial propagation, the length of the transmission line can be obtained.

  In the first to fourth embodiments, the frequency of the signal output from the voltage controlled oscillator 14 is the frequency of the electromagnetic wave propagated from the first transmission / reception device 100 to the second transmission / reception device 200. However, the output signal of the voltage controlled oscillator 14 may be the frequency of the electromagnetic wave of spatial propagation, which is obtained by multiplying, dividing, or frequency-shifting the frequency by a multiplier, a dividing period, or a mixer. In this case, when the frequency of the transmitter is not converted, the voltage-controlled oscillator 14 becomes a transmitter, and this transmitter and the amplifier 15 as necessary constitute this transmitter. In the case of frequency conversion, the transmitter includes a multiplier, a division period, a mixer, an amplifier, and the like. When converting the frequency, the frequency may be converted by a PLL circuit using a phase comparator, a reference signal, a multiplier / divider, and a mixer. Similarly, the first frequency converter 12 and the second frequency converter 50 may also be configured by a PLL circuit using a phase comparator, a reference signal, a multiplier / divider, and a mixer.

  In the above embodiment, the analysis by the single frequency sine wave is shown, but the signal transmitted from the first transmission antenna and the second transmission antenna may be a single frequency sine wave (cosine wave). Regarding signal processing inside the first transmission / reception device and the second transmission / reception device, even if signal processing is performed with a rectangular wave (square wave) having a single frequency (single period as a rectangular wave) synchronized with a sine wave. good. Therefore, the first phase comparator, the second phase comparator, and the other phase comparators may be digital frequency phase comparators that input rectangular waves. The outputs of the reference oscillator and the voltage controlled oscillator may be sine waves or rectangular waves.

  The present invention includes a first transmission / reception device having a different transmission / reception frequency in each of a plurality of transport devices in a factory or a warehouse, such as a forklift, for example, for a plurality of workers walking in the factory or a warehouse. By carrying the two transmission / reception devices, it can be used as a warning device that informs the operator of the transport device of the presence of nearby workers.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the distance measuring device which concerns on the specific Example 1 of this invention. The block diagram of the distance measuring device which concerns on the specific Example 2 of this invention. The block diagram of the distance measuring device which concerns on the specific Example 3 of this invention. The block diagram of the distance measuring device which concerns on the specific Example 4 of this invention. The block diagram of the distance measuring apparatus which concerns on the specific Example 6 of this invention. The block diagram of the distance measuring apparatus which concerns on the specific Example 7 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... 1st transmission / reception apparatus 200 ... 2nd transmission / reception apparatus 10 ... Reference | standard oscillator 11 ... 1st phase comparator 16 ... 2nd phase comparator 12 ... 1st frequency converter 14 ... Voltage controlled oscillator 50 ... 2nd frequency converter 120 ... Mixer 121 ... Multiplier

Claims (5)

In a distance measuring device that includes a first transmitting / receiving device and a second transmitting / receiving device, and that measures a distance between the first transmitting / receiving device and the second transmitting / receiving device,
The first transmitting / receiving device includes:
A first transmitting antenna for transmitting a signal to the second transmitting / receiving device;
A first receiving antenna for receiving a transmission signal from the second transmitting / receiving device;
A reference oscillator that outputs a signal having a predetermined waveform at a predetermined reference frequency; and
A first frequency converter that inputs a signal received by the first receiving antenna and converts the signal into a reference frequency signal;
A first phase comparator for comparing phases of an output signal of the reference oscillator and an output signal of the first frequency converter;
A voltage-controlled oscillator that changes the phase and frequency of the waveform so that the phase difference compared by the first phase comparator becomes zero;
A transmitter that outputs the frequency of the output signal of the voltage controlled oscillator to the first transmitting antenna as a single frequency sine wave signal by converting the frequency of the output signal to a predetermined frequency;
A second phase comparator that compares the phase of the output signal of the voltage controlled oscillator with the phase of the output signal of the reference oscillator and outputs a signal corresponding to the phase difference as a distance signal;
Have
The second transmission / reception device includes:
A second receiving antenna for receiving a signal transmitted from the first transmitting / receiving device;
A second transmitting antenna for transmitting a signal to the first transmitting / receiving device;
A second frequency converter that converts the frequency of the signal received by the second receiving antenna and outputs the converted signal to the second transmitting antenna;
A distance measuring device comprising:   The first frequency converter includes a multiplier that multiplies the frequency of the output signal of the reference oscillator, or a frequency divider that divides, a received signal of the first receiving antenna, and a multiplier or a divider. The distance measuring device according to claim 1, further comprising a mixer for obtaining a product with the output signal.   The first frequency converter includes a multiplier that multiplies the frequency of the output signal of the voltage controlled oscillator, or a frequency divider that divides, a received signal of the first receiving antenna, and the multiplier or divider. The distance measuring device according to claim 1, further comprising a mixer that obtains a product of the output signal of   The second frequency converter includes a voltage-controlled oscillator that generates a signal having the same frequency and the same phase as a reception signal by the second reception antenna, and a multiplier that multiplies the frequency of the output signal of the voltage-controlled oscillator or a frequency-dividing component. The distance measuring device according to claim 2, further comprising a peripheral. The second transmitting / receiving device includes a second reference oscillator that oscillates a signal having a predetermined frequency,
The second frequency converter includes a second multiplier that multiplies the frequency of the output signal of the second reference oscillator, or a second divider that divides the frequency, a received signal of the second receiving antenna, and the second A second mixer for determining a product with the output signal of the doubler or the second divider;
The distance measuring device according to any one of claims 1 to 4, further comprising: a second voltage controlled oscillator that converts a frequency of an output signal of the second mixer.

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