Measuring system

Abstract

Embodiments of the invention relate to a measurement system. According to one embodiment, a measurement system includes a master device, a reference device, and a determination unit. The master device includes a signal generating unit, a signal dividing unit, a master antenna unit, and a master data signal processing unit. The signal generation unit generates a modulation signal. The signal dividing unit divides the generated signal. The main antenna unit transmits and receives a first signal to and from an object to be measured. The main data signal processing unit performs processing using the first signal and the third signal. The reference device includes a delay unit and a reference data signal processing unit. The delay unit provides a delay to the second signal. The reference data signal processing unit performs processing using the second signal and the third signal. The determination unit measures the displacement of the measurement object on the basis of the processing results obtained by the master device and the processing results obtained by the reference device.

Description

[0001] This application is based on Japanese Patent Application No. 2024-012682 (filing date: January 31, 2024) and claims priority based on these applications. This application incorporates the entire content of these applications by reference. Technical Field

[0002] Embodiments of the present invention relate to a measurement system. Background Art

[0003] For example, in thickness measurement on a rolling production line, accuracy in the order of several tens of micrometers to several micrometers is required. In conventional thickness measurement instruments, X-rays or γ-rays are irradiated onto the object to be measured and the rays are transmitted through for measurement. However, there are problems in terms of environmental tolerance and cost, so thickness measurement using a low-cost and environmentally tolerant millimeter-wave radar has been studied.

[0004] German Patent Invention No. 102019101152 discloses a method for detecting a depression in a thick plate in thickness measurement using a millimeter-wave radar and a laser.

[0005] However, in German Patent Invention No. 102019101152, the influence of phase noise and vibration in an actual production line on the measurement accuracy is not mentioned. In the measurement of minute displacements in an actual millimeter-wave radar, the following two points are considered major problems.

[0006] The first point is the influence of analog distortion (phase noise, temperature characteristics, etc.) of the reference signal source, and the second point is the influence of vibration in the surrounding installation environment and vibration applied during operation (even if vibration prevention measures are introduced, it cannot be completely eliminated).

[0007] These are problems peculiar to radars that perform frequency modulation and phase modulation. The reason is that the excitation of the lens in the vibration generating part of the radar fluctuates due to vibration and temperature changes. As a result, problems such as instability in the measurement of minute displacements and inability to perform long-term measurements occur.

[0008] In addition, Japanese Unexamined Patent Application Publication No. 2011-183450 discloses a method for reducing noise for noise components from the transmitted signal that wraps around to the received signal as a method for removing noise components in an FMCW radar.

[0009] However, Japanese Unexamined Patent Application Publication No. 2011-183450 does not pay attention to the noise components carried by the transmitted signal itself.

[0010] Thus, in conventional minute displacement measurement using a millimeter-wave radar, the excitation of the lens fluctuates due to vibration and temperature changes, resulting in problems such as fluctuations in the displacement measurement results. Summary of the Invention

[0011] The problem to be solved by the present invention is to provide a measurement system that can eliminate the instability of displacement measurement caused by the distortion of the transmitted signal due to external factors such as temperature changes and vibrations in an actual thick plate production line or the like.

[0012] According to an embodiment, the measurement system includes a main device, a reference device, and a determination unit. The main device includes a signal generation unit, a signal splitting unit, a main antenna unit, and a main data signal processing unit. The signal generation unit generates a phase-modulated or frequency-modulated signal. The signal splitting unit splits the signal generated by the signal generation unit into a plurality of signals including at least a first signal, a second signal, and a third signal. The main antenna unit transmits the first signal to the measurement object and receives the first signal from the measurement object. The main data signal processing unit performs signal processing using the first signal and the third signal transmitted and received by the main antenna unit. The reference device includes a delay unit and a reference data signal processing unit. The delay unit provides a delay to the second signal supplied from the main device. The reference data signal processing unit performs signal processing using the second signal and the third signal provided with the delay by the delay unit. The determination unit measures the displacement of the measurement object based on the signal processing result of the main data signal processing unit output from the main device and the signal processing result of the reference data signal processing unit output from the reference device.

[0013] According to the measurement system having the above structure, it is possible to eliminate the instability of displacement measurement caused by the distortion of the transmitted signal due to external factors such as temperature changes and vibrations in an actual thick plate production line or the like. Brief Description of the Drawings

[0014] Figure 1 is a block diagram showing a structural example of the measurement system according to the first embodiment.

[0015] Figure 2 is Figure 1 the circuit diagram of the radar system in the block diagram.

[0016] Figure 3 is the circuit diagram of the signal generation unit included in the measurement system according to the first embodiment.

[0017] Figure 4 is a diagram showing a method for discriminating variable factors that appear in the measurement result of the measurement object in the measurement system according to the first embodiment.

[0018] Figure 5 is a diagram showing an application example of the measurement system according to the first embodiment.

[0019] Figure 6 is the circuit diagram of the radar system that uses a reference antenna unit to form the delay unit of the reference device in the measurement system according to the first embodiment.

[0020] Figure 7 This is a diagram showing a modification of the arrangement of the reference antenna unit in the measurement system of the first embodiment.

[0021] Figure 8 This is a diagram showing a modification of using the measurement system of the first embodiment to measure the displacement of the thickness of an object to be measured.

[0022] Figure 9 This is a circuit diagram of a radar system that uses a delay element to form the delay section of the reference device in the measurement system of the second embodiment.

[0023] Figure 10 This is a diagram showing an application example of the measurement system of the second embodiment.

[0024] (Reference Signs)

[0025] 1: Object to be measured; 2: Thick plate production line; 3: Reference target; 10: Measurement system; 100: Main device; 110: Reference device; 120: Comprehensive determination unit; 130: Display unit; 1000: Signal generation unit; 1100: Signal splitting unit; 1200: Main antenna unit; 1210: Delay section; 1211: Reference antenna unit; 1214: Delay element; 1300: Main data signal processing unit; 1310: Reference data signal processing unit. Detailed Embodiments

[0026] Hereinafter, embodiments will be described with reference to the drawings.

[0027] (First Embodiment)

[0028] Figure 1 This is a block diagram showing a structural example of the measurement system 10 of the first embodiment.

[0029] The measurement system 10 is a system that measures the displacement of an object to be measured using a millimeter-wave radar. The measurement system 10 includes a main device 100, a reference device 110, a comprehensive determination unit 120, and a display unit 130.

[0030] The main device 100 measures the object to be measured using a millimeter-wave radar. More specifically, the main device 100 transmits a phase-modulated or frequency-modulated signal to the object to be measured, receives the signal from the object to be measured, and measures the distance to the object to be measured.

[0031] The reference device 110 is configured to share the reference signal source of the main device 100 as its own reference signal source, and generates reference data (signal) for reducing phase distortion during signal generation and frequency fluctuations caused by vibration based on the measurement result of the main device 100.

[0032] More specifically, the reference device 110 receives the supply of the same signal as the signal transmitted by the main device 100 to the object to be measured, and adds a delay of the same degree as the delay of the signal generated due to the measurement (transmission and reception of the signal) of the object to be measured in the main device 100. Here, the delay of the same degree means a delay that is generally the same but not exactly the same. In order to add this delay, the reference device 110 has a delay unit 1210 described later.

[0033] The comprehensive determination unit 120 measures the displacement of the object to be measured based on the outputs of the main device 100 and the reference device 110. At this time, the comprehensive determination unit 120 obtains the difference between the respective outputs, thereby reducing the phase distortion when generating the signal and the frequency fluctuation caused by vibration from the measurement result.

[0034] The display unit 130 displays the measurement result of the displacement of the object to be measured output from the comprehensive determination unit 120. The measurement result displayed on the display unit 130 can be, for example, the displacement amount, whether displacement has occurred, or the distance from the object to be measured.

[0035] The main device 100 includes a signal generation unit 1000, a signal splitting unit 1100, a main antenna unit 1200, and a main data signal processing unit 1300.

[0036] The signal generation unit 1000 is a common reference signal source for the above-mentioned main device 100 and reference device 110, and generates a phase-modulated or frequency-modulated signal (transmission signal).

[0037] The signal splitting unit 1100 splits the signal generated by the signal generation unit 1000 into a first signal, a second signal, and a third signal. The first signal among these three signals is supplied to the main antenna unit 1200, and the second signal and the third signal are supplied to the reference device 110.

[0038] The main antenna unit 1200 transmits the first signal supplied from the signal splitting unit 1100 to the object to be measured. In addition, the main antenna unit 1200 receives the first signal from the object to be measured reflected by the object to be measured.

[0039] The main data signal processing unit 1300 performs signal processing using the first signal transmitted and received by the main antenna unit 1200 and the third signal supplied from the signal splitting unit 1100 that has not been transmitted and received by the main antenna unit 1200. Specifically, it performs signal processing for calculating the distance from the main antenna unit 1200 to the object to be measured 1.

[0040] On the other hand, the reference device 110 includes a delay unit 1210 and a reference data signal processing unit 1310.

[0041] The delay unit 1210 adds the same degree of delay as the delay of the signal (the first signal) generated due to the measurement (transmission and reception of signals) of the measurement object in the main device 100 to the second signal supplied from the signal splitting unit 1100 of the main device 100. Details of the delay added to the signal by the delay unit 1210 will be described later.

[0042] The reference data signal processing unit 1310 performs signal processing using the second signal to which the delay is added by the delay unit 1210 and the third signal supplied from the signal splitting unit 1100 to which the delay is not added by the delay unit 1210. Specifically, signal processing for calculating the distance from the reference antenna unit 1211 to the reference target 3 is performed.

[0043] Figure 2 is Figure 1 the circuit diagram of the radar system in the block diagram of the measurement system 10 shown.

[0044] As described above, the phase-modulated or frequency-modulated signal (transmission signal) generated by the signal generation unit 1000 is split by the signal splitting unit 1100 into three signals: the first signal, the second signal, and the third signal.

[0045] The first signal is supplied to the main antenna unit 1200. The first signal supplied to the main antenna unit 1200 is transmitted from the main antenna unit 1200 to the measurement object, reflected by the measurement object, and received by the main antenna unit 1200. Due to the transmission and reception by the main antenna unit 1200, a delay is generated in the first signal.

[0046] The second signal is supplied to the delay unit 1210. The second signal supplied to the delay unit 1210 is added with the same degree of delay as the delay of the first signal by the delay unit 1210.

[0047] The third signal is a signal that is not transmitted and received by the main antenna unit 1200 and is a signal to which no delay is added by the delay unit 1210. The first signal transmitted and received by the main antenna unit 1200 and the third signal that is not transmitted and received by the main antenna unit 1200 are mixed by the mixer 1400. In addition, the second signal to which the delay is added by the delay unit 1210 and the third signal to which no delay is added by the delay unit 1210 are mixed by the mixer 1410.

[0048] More specifically, in the mixer 1400, the first beat signal is extracted from the first signal and the third signal, and in the mixer 1410, the second beat signal is extracted from the second signal and the third signal. The first beat signal is supplied to the main data signal processing unit 1300, and the second beat signal is supplied to the reference data signal processing unit 1310.

[0049] The main data signal processing unit 1300 and the reference data signal processing unit 1310 respectively perform signal processing for deriving the distance to the measurement object using the supplied beat signals (the first beat signal, the second beat signal). The respective processing results are supplied to the comprehensive determination unit 120.

[0050] The comprehensive determination unit 120 removes the noise component commonly observed in both the output of the main data signal processing unit 1300 and the output of the reference data signal processing unit 1310 from the output of the main data signal processing unit 1300, and outputs it as the measurement result (distance) of the measurement object. This noise component is phase distortion during signal generation and frequency fluctuations caused by vibration.

[0051] Figure 3 It is a circuit diagram of the signal generation unit 1000.

[0052] Here, an example is shown in the case where the signal generation unit 1000 generates a phase-modulated signal using the phase modulator 1001 and the oscillator 1002. As Figure 3 shown, the signal generated by the signal generation unit 1000 is affected by interference a1 such as vibration and temperature change, and may contain fluctuations.

[0053] Figure 4 It is a diagram showing a method for discriminating variable factors appearing in the measurement result of the main device 100 in the measurement system 10 of the first embodiment.

[0054] In the measurement system 10 of the first embodiment having the reference device 110, when a variation appears in the measurement result of the main device 100 due to the above interference a1, it will not be erroneously determined that the displacement of the measurement object is detected, but it can be correctly determined that this is caused by the interference a1 and the displacement of the measurement object is not detected.

[0055] Figure 4 (A) of shows an example where the measurement result of the main device 100 is different from the measurement result of the reference device 110, and it is determined that the displacement of the measurement object is detected by comparing them. The vertical axis of the graph representing the measurement result of the main device 100 and the measurement result of the reference device 110 is displacement, and the horizontal axis is time. In addition, the vertical axis of the graph representing the determination result is the displacement amount, and the horizontal axis is time.

[0056] Figure 4 (B) of shows an example where the measurement result of the main device 100 is the same as the measurement result of the reference device 110, and it is determined that the displacement of the measurement object is detected by comparing them. The measurement result of the main device 100 being the same as the measurement result of the reference device 110 means that the noise component is commonly observed in both. In addition, Figure 4 In (B) of, the vertical axis and the horizontal axis of each graph are the same as those inFigure 4 The vertical and horizontal axes of the respective graphs in (A) are the same.

[0057] Figure 5 FIG. 5 is a diagram showing an application example of the measurement system 10 according to the first embodiment. Here, an example of applying the measurement system 10 as a system for detecting unevenness on the surface of a measurement object (thick plate) 1 is shown.

[0058] The measurement object (thick plate) 1 moves in the A direction on the thick plate production line 2. The measurement system 10 is arranged such that the main antenna unit 1200 transmits a first signal to the measurement object (thick plate) 1 moving on the thick plate production line 2, and the main antenna unit 1200 receives the first signal reflected from the measurement object (thick plate) 1 via the measurement object (thick plate) 1.

[0059] In addition, in the measurement system 10 of the first embodiment, the delay unit 1210 of the reference device 110 is configured by the reference target 3 and the reference antenna unit 1211 that transmits a second signal to the reference target 3 and receives the second signal reflected from the reference target 3 via the reference target 3. The distance from the reference antenna unit 1211 to the reference target 3 is set to be substantially the same but not exactly the same as the distance from the main antenna unit 1200 to the measurement object (thick plate) 1. Thus, through the transmission and reception performed by the reference antenna unit 1211, a delay substantially the same but not exactly the same as the delay generated in the first signal is added to the second signal.

[0060] Figure 6 FIG. 15 is a circuit diagram of a radar system in which the delay unit 1210 of the reference device 110 is configured using the reference antenna unit 1211.

[0061] As described above, the signal splitting unit 1100 splits the signal generated by the signal generation unit 1000 into a first signal, a second signal, and a third signal. To perform this splitting, the signal splitting unit 1100 includes a distributor 1101.

[0062] In addition, as described above, the second signal is supplied from the signal splitting unit 1100 to the delay unit 1210. The second signal supplied to the delay unit 1210 is transmitted from the reference antenna unit 1211 to the reference target 3, reflected by the reference target 3, and received by the reference antenna unit 1211. Through the transmission and reception performed by the reference antenna unit 1211, the delay unit 1210 adds a delay of the same degree as the delay of the first signal to the second signal.

[0063] The first signal transmitted and received by the main antenna unit 1200 and the second signal transmitted and received by the reference antenna unit 1211 are combined by the combiner 1430. The combined signal generated by the combiner 1430 is supplied to the mixer 1400 and the mixer 1410.

[0064] The mixer 1400 extracts a first beat signal from the first signal in the combined signal supplied by the synthesizer 1430 and the third signal supplied by the signal generator 1000. The first beat signal extracted by the mixer 1400 is supplied to the main data signal processing unit 1300.

[0065] The mixer 1410 extracts a second beat signal from the second signal in the combined signal supplied by the synthesizer 1430 and the third signal supplied by the signal generator 1000. The second beat signal extracted by the mixer 1410 is supplied to the reference data signal processing unit 1310.

[0066] Next, the details of the signal processing of the main data signal processing unit 1300 and the reference data signal processing unit 1310 will be described.

[0067] The transmission signal (chirp signal) generated by the signal generator 1000 can be represented by the following equation (1).

[0068]

Mathematical formula 1

[0069]

[0070] Here, the start frequency of the chirp signal is f c , the bandwidth is B, the chirp time is T c , and the chirp slope is S. The signal splitting unit 1100 divides this signal into a transmission signal (first signal) mainly used, a reference transmission signal (second signal), and signals (third signal) used when receiving the first signal and the second signal, respectively.

[0071] When the distance to the measurement object 1 is set to d, the signal that can be received by the main antenna unit 1200 that transmits and receives the first signal can be represented by the following equation (2).

[0072]

Mathematical formula 2

[0073]

[0074] Here, A is a coefficient including the reflection coefficient and the distance attenuation. In addition, τ = 2d / c, which is the time taken from transmission until hitting the measurement object 1 and being received, and c is the speed of light.

[0075] In addition, the signal that can be received by the reference antenna unit 1211 that transmits and receives the second signal can also be represented by equation (2) if the distance to the reference target 3 is set to d.

[0076] Regarding Formula (1) and Formula (2), a mixer (Mixers 1400 and 1410) is used for mixing. The intermediate frequency (IF) signals (the first beat signal and the second beat signal) passing through the low-pass filter are represented by the following Formula (3).

[0077]

Mathematical Formula 3

[0078] s(t) = A exp(j2Π(Sτt + f c τ)) Formula (3)

[0079] The initial phase of this signal is 2πf c τ = Φ IF , and the frequency is Sτ = f IF .

[0080] The main data signal processing unit 1300 and the reference data signal processing unit 1310 input the IF signal represented by Formula (3), perform frequency analysis on this signal to obtain the frequency, calculate the distance based on it, and thus perform distance estimation. The signals obtained by performing AD conversion on this IF signal are represented by the following Formulas (4) to (6).

[0081]

Mathematical Formula 4

[0082] s[n] = A exp(jnω IF ) exp(jΦ IF ) Formula (4)

[0083] Here, ω IF = 2πf IF , 0 ≤ n < N s , the number of sampling points is N s , and the sampling frequency is F s .

[0084]

Mathematical Formula 5

[0085]

[0086]

Mathematical Formula 6

[0087]

[0088] The power spectrum of X(k) is maximum when (2π / N[[ID=5%]] s )k - ω IF = 0. If the k that satisfies this is set as k r , then it can be calculated as:

[0089]

Mathematical Formula 7

[0090]

[0091] Call it the distance library. Additionally, at this time, the phase of X(kr) can be represented by exp(jΦ IF ). The range resolution of the range FFT depends on the bandwidth B of the chirp signal and is represented by Equation (8) below.

[0092]

Mathematical formula 8

[0093]

[0094] When measuring the displacement of the measurement object 1 on the thick plate production line, it is necessary to measure the displacement in units of micrometers. However, according to Equation (8), the required bandwidth of the chirp signal for such a small displacement measurement is above several THz, which is not realistic. Therefore, the micro-Doppler technique is used to measure the displacement.

[0095] At the position of range r0 from the radar, perform a range FFT on the object vibrating with amplitude ad m (t). If the phase in the distance library is obtained, it is represented by Equation (9) below.

[0096]

Mathematical formula 9

[0097]

[0098] Here, the time taken for transmission and reception is short, so ad m is assumed to be constant. The information of this phase is obtained through the transmission and reception of a single chirp signal. By continuously performing the transmission and reception of this chirp signal, the phase generated by the vibration changes with the time variation of the vibration amplitude. Therefore, it is represented by Equation (10) below.

[0099]

Mathematical formula 10

[0100]

[0101] Send the signal multiple times to obtain the phase at the vibrating object. By paying attention to the change in the phase caused by the displacement of the iron plate, the displacement of the measurement object 1 can be measured based on the phase.

[0102] That is, the processing performed by the main data signal processing unit 1300 and the reference data signal processing unit 1310 can be described as follows.

[0103] 1. After performing AD conversion on the input IF signal and then performing FFT, obtain the distance library.

[0104] 2. Extract the phase information from the obtained distance library.

[0105] Next, the details of the processing of the comprehensive determination unit 120 will be described.

[0106] Among the phase information of the measurement object 1 obtained by the main data signal processing unit 1300 of the main device 100 and the phase information of the stationary reference target 3 obtained by the reference data signal processing unit 1310 of the reference device 110, substantially the same distortion caused by phase noise and fluctuation of the phase caused by vibration are observed. After the comprehensive determination unit 120 removes the common phase fluctuation by subtracting the phase information of the reference device 110 from the phase information of the main device 100, it extracts the phase information without noise components.

[0107] In this way, by performing signal generation, transmission / reception, and signal processing as described above, the measurement system 10 of the first embodiment can display only the measurement result with reduced phase fluctuation on the display unit 130 at low cost and perform long-term stable displacement measurement.

[0108] That is, the measurement system 10 of the first embodiment can eliminate the instability of displacement measurement caused by the distortion of the transmitted signal due to external factors such as temperature change and vibration in an actual thick plate production line.

[0109] In addition, in Figure 5 , as an example of the setting of the reference antenna unit 1211 and the reference target 3, an example is shown in which the reference antenna unit 1211 is arranged in parallel with the main antenna unit 1200 with respect to the moving direction (A direction) of the measurement object 1. However, it is not limited to this. Regarding the reference antenna unit 1211 and the reference target 3, if it is within the range where the environment can be regarded as the same as that of the main antenna unit 1200 and the measurement object 1, they can be set in various forms. In Figure 7 , a modified example of the setting of the reference antenna unit 1211 and the reference target 3 is shown.

[0110] In addition, in Figure 5 , an example is shown in which the measurement system 10 of the first embodiment measures the displacement of the surface of the measurement object 1 moving on the thick plate production line 2. As Figure 8 shown, by further adding the measurement system 10 of the first embodiment to the use of measuring the displacement of the back surface of the measurement object 1 moving on the thick plate production line 2, the measurement system 10 of the first embodiment can be used to measure the displacement of the thickness of the measurement object 1 moving on the thick plate production line 2.

[0111] (Second Embodiment)

[0112] Next, the second embodiment will be described.

[0113] In the measurement system 10 of the first embodiment, the reference antenna unit 1211 is used to form the delay unit 1210. Specifically, by transmitting a signal from the reference antenna unit 1211 to the reference target 3 and receiving the signal from the reference target 3 by the reference antenna unit 1211, a delay of the same degree as the delay generated when the main device 100 measures the displacement of the measurement object 1 (the delay accompanying the transmission and reception of the signal between the main antenna unit 1200 and the measurement object 1) is generated.

[0114] In contrast, the measurement system 10 of the second embodiment uses a delay element instead of the reference antenna unit 1211 to generate a delay. Figure 9 It is a circuit diagram of a radar system in which the delay element 1214 is used to form the delay unit 1210 of the reference device 110 in the measurement system 10 of the second embodiment.

[0115] In the measurement system 10 of the second embodiment, the delay unit 1210 generates a delay of the same degree as the delay generated when the main device 100 measures the displacement of the measurement object 1 (the delay accompanying the transmission and reception of the signal between the main antenna unit 1200 and the measurement object 1) by supplying the second signal from the distributor 1101 of the signal splitting unit 1100 to the delay element 1214. Similarly to the case of the first embodiment, the delay of the same degree here also refers to a delay that is generally the same but not exactly the same.

[0116] The first signal transmitted and received by the main antenna unit 1200 and the second signal with a delay added by the delay element 1214 are synthesized by the synthesizer 1430. The synthesized signal generated by the synthesizer 1430 is supplied to the mixer 1400 and the mixer 1410.

[0117] Next, similarly to the measurement system 1 of the first embodiment, the mixer 1400 extracts the first beat signal from the first signal in the synthesized signal supplied by the synthesizer 1430 and the third signal supplied by the signal generation unit 1000. The mixer 1410 extracts the second beat signal from the second signal in the synthesized signal supplied by the synthesizer 1430 and the third signal supplied by the signal generation unit 1000.

[0118] Thus, also in the measurement system 10 of the second embodiment that uses the delay element 1214 to generate a delay, it is possible to eliminate the instability of the displacement measurement caused by the distortion of the transmitted signal due to external factors such as temperature changes and vibrations in an actual thick plate production line.

[0119] Figure 10 It is a diagram showing an application example of the measurement system 10 of the second embodiment. Here, an example of applying the measurement system 10 as a system for detecting the unevenness of the measurement object (thick plate) 1 is also shown.

[0120] As Figure 10 shown, since the measurement system 10 of the second embodiment does not require the setting of the reference antenna unit 1211 and the reference target 3, it is possible to eliminate the instability of displacement measurement caused by the distortion of the transmitted signal due to external factors such as temperature changes and vibrations in an actual thick plate production line at a lower cost.

[0121] In addition, the present invention is not limited to the above-described embodiments. At the implementation stage, the structural elements can be deformed within the scope not departing from the gist thereof to be embodied. Further, by appropriately combining a plurality of structural elements disclosed in the above-described embodiments, various inventions can be formed. For example, several structural elements can be deleted from all the structural elements shown in the embodiments. Furthermore, the structural elements between different embodiments can be appropriately combined.

[0122] This embodiment includes the following features.

[0123] [Remarks 1]

[0124] A measurement system includes:

[0125] A main device;

[0126] A reference device; and

[0127] A determination unit,

[0128] The main device includes:

[0129] A signal generation unit that generates a signal subjected to phase modulation or frequency modulation;

[0130] A signal splitting unit that splits the signal generated by the signal generation unit into a plurality of signals including at least a first signal, a second signal, and a third signal;

[0131] A main antenna unit that transmits the first signal to a measurement object and receives the first signal from the measurement object; and

[0132] A main data signal processing unit that performs signal processing using the first signal and the third signal transmitted and received by the main antenna unit,

[0133] The reference device includes:

[0134] A delay unit that provides a delay to the second signal supplied from the main device; and

[0135] A reference data signal processing unit that performs signal processing using the second signal and the third signal provided with the delay by the delay unit,

[0136] The determination unit measures the displacement of the object to be measured based on the signal processing results of the main data signal processing unit output from the main device and the signal processing results of the reference data signal processing unit output from the reference device.

[0137] [Remarks 2]

[0138] In Remarks 1,

[0139] The main data signal processing unit uses the first signal and the third signal transmitted and received by the main antenna unit to extract a first beat signal, and calculates the frequency characteristics through spectrum analysis.

[0140] [Remarks 3]

[0141] In Remarks 1,

[0142] The delay unit has a reference antenna unit, and provides a delay to the second signal by transmitting the second signal from the reference antenna unit to a reference target different from the object to be measured and receiving the second signal from the reference target by the reference antenna unit.

[0143] [Remarks 4]

[0144] In Remarks 3,

[0145] The distance between the reference antenna unit and the reference target differs from the distance between the main antenna unit and the object to be measured by a difference within a predetermined range.

[0146] [Remarks 5]

[0147] In Remarks 1,

[0148] The delay unit has a delay element, and uses the delay element to provide a delay to the second signal.

[0149] [Remarks 6]

[0150] In Remarks 5,

[0151] The amount of delay provided to the second signal by the delay element differs from the amount of delay generated in the first signal through transmission and reception by the main antenna unit in the main device by a difference within a predetermined range.

[0152] [Remarks 7]

[0153] In Remarks 1,

[0154] The reference data signal processing unit uses the second signal and the third signal provided with a delay by the delay unit to extract a second beat signal, and calculates the frequency characteristics through spectrum analysis.

[0155] [Remarks 8]

[0156] In Remarks 1,

[0157] the determination unit reduces the influence of analog distortion or vibration on the measurement result of the displacement of the object to be measured by obtaining the difference between the signal processing result of the main data signal processing unit output from the main device and the signal processing result of the reference data signal processing unit output from the reference device.

Claims

1. A measurement system, comprising: A main device; A reference device; and A determination unit, The main device comprises: A signal generation unit that generates a phase-modulated or frequency-modulated signal; A signal splitting unit that splits the signal generated by the signal generation unit into a plurality of signals including at least a first signal, a second signal, and a third signal; A main antenna unit that transmits the first signal to a measurement object and receives the first signal from the measurement object; And A main data signal processing unit that performs signal processing using the first signal and the third signal transmitted and received by the main antenna unit, The reference device comprises: A delay unit that provides a delay to the second signal supplied from the main device; and A reference data signal processing unit that performs signal processing using the second signal and the third signal provided with a delay by the delay unit, The determination unit measures the displacement of the measurement object based on the signal processing result of the main data signal processing unit output from the main device and the signal processing result of the reference data signal processing unit output from the reference device.

2. The measurement system according to claim 1, wherein The main data signal processing unit uses the first signal and the third signal transmitted and received by the main antenna unit to extract a first beat signal and calculates the frequency characteristics through spectrum analysis.

3. The measurement system according to claim 1, wherein The delay unit has a reference antenna unit that provides a delay to the second signal by transmitting the second signal from the reference antenna unit to a reference target different from the measurement object and receiving the second signal from the reference target by the reference antenna unit.

4. The measurement system according to claim 3, wherein The distance between the reference antenna unit and the reference target differs from the distance between the main antenna unit and the measurement object by a difference within a predetermined range.

5. The measurement system according to claim 1, wherein The delay unit has a delay element and uses the delay element to provide a delay to the second signal.

6. The measurement system according to claim 5, wherein The amount of delay provided to the second signal by the delay element differs from the amount of delay generated in the first signal by transmission and reception by the main antenna unit in the main device by a difference within a predetermined range.

7. The measurement system according to claim 1, wherein The reference data signal processing unit uses the second signal and the third signal provided with a delay by the delay unit to extract a second beat signal and calculates the frequency characteristics through spectrum analysis.

8. The measurement system according to claim 1, wherein The determination unit reduces the influence of analog distortion or vibration on the measurement result of the displacement of the measurement object by obtaining the difference between the signal processing result of the main data signal processing unit output from the main device and the signal processing result of the reference data signal processing unit output from the reference device.

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