JP6721262B1 - Charge state detection device, earthquake prediction method, lightning strike prediction method, and electrostatic discharge prediction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect and predict an earthquake easily with a simple and small device, and to detect and predict a lightning strike. A method and an electrostatic discharge prediction method are provided. SOLUTION: A detector 100 irradiates an electric wave to a dielectric member 102 installed on the surface of the earth, and changes in the permittivity of the dielectric member 102 on the surface of the earth (changes in charge amount) from a differential distance spectrum of a standing wave radar. ) Is measured. At this time, if there is an increase or decrease in the amount of static electricity in the measurement unit on the ground surface, this appears as a change in the dielectric constant. On the other hand, the amount of static electricity on the ground surface changes before the occurrence of an earthquake or lightning strike. Therefore, when this increase/decrease in the dielectric constant is detected, it is due to the increase/decrease in the amount of static electricity, so it is used for prediction of an earthquake or lightning strike. The present invention can also be used for predicting electrostatic discharge due to an increase in the withstand voltage of static electricity on clothes. [Selection diagram] Figure 1

Description

The present invention relates to a device for detecting a charged state on the ground surface using a standing wave radar, and more particularly to a method for predicting an earthquake and a lightning strike and a method for predicting electrostatic discharge using the device.

Conventionally, as a technique for predicting or forecasting an earthquake, a technique utilizing various measurement principles has been proposed. For example, Patent Document 1 proposes a device in which crustal deformation occurs as a pre-stage of an earthquake, but changes in charges on the ground surface caused by this crustal deformation are measured and used for earthquake prediction. There is. In this surface potential measuring device, a surface electrode plate is installed on the surface of the earth, and a measuring electrode plate having a charge opposite to that of the surface electrode plate is provided so as to face the surface electrode plate, and the potential between them is measured. .. In addition, Patent Document 2 discloses a method of performing earthquake prediction using a special waveform pattern observed in connection with the occurrence of crustal destruction as a pre-stage of an earthquake. In this method, a counter electrode is buried in the ground. The prediction information transmission system of the subduction zone earthquake disclosed in Patent Document 3 is provided with a plurality of observation points in the epicenter area where the subduction zone earthquake is assumed, and geomagnetic detection means provided at the observation points distant from the observation points, respectively. Observe the geomagnetic variations. Then, when the variation value of the total geomagnetic force in the assumed source region exceeds a predetermined reference value, the variation is determined to be abnormal and the earthquake prediction information is output. In Patent Document 4, radio waves of two or more types of frequencies are received from an arbitrary satellite, the total number of electrons (STEC) in the route through which the radio waves pass is calculated, and this STEC shows a positive change over time. There is disclosed an earthquake occurrence prediction device that determines whether or not an earthquake has occurred and outputs an alert for the occurrence of an earthquake according to the result of the determination. In Patent Document 5, electronic reference point position information, which is information about the position of an electronic reference point corresponding to one point and which is information about the position at two or more times, is obtained, and the electronic reference in the first period is calculated. An apparatus is disclosed which acquires change information regarding a change in point position information and utilizes a phenomenon in which a change in the electronic reference point position information becomes small immediately before an earthquake occurs to perform an earthquake prediction.

JP, 2010-91557, A JP, 2013-195411, A JP, 2014-174128, A JP, 2016-218069, A Japanese Patent No. 6397972

However, in these conventional techniques, it is necessary to previously install a measuring device at a position where an earthquake should be observed. Therefore, it is necessary to install many measuring devices all over Japan. In addition, a complicated and large-scale device is required for the measurement. On the other hand, after driving the car, when the door knob is operated to get off the vehicle, discharge occurs. Such a discharge has a significantly unpleasant effect on the human body.

The present invention has been made in view of such problems, and it is possible to easily predict or predict an earthquake with a simple and small-sized device, and also to predict/predict lightning strikes, and further to prevent static electricity. It is an object of the present invention to provide a charged state detection device capable of predicting/predicting electric discharge of the same, a method of predicting an earthquake, a method of predicting a lightning strike, and a method of predicting electrostatic discharge.

In the present invention, the term "on the ground surface" refers to a region from the ground to a height at which electric charges generated on the ground can be charged, and is not limited to the ground or its vicinity.

The charged state detection device according to the present invention is
The frequency-swept radio wave is transmitted to the outside, the reflected wave reflected by the dielectric member is detected at two points separated by a certain distance based on the transmission wavelength, and the standing wave synthesized from the transmission wave and the reception wave is detected. A standing wave detector that detects
From the intensity distribution of the frequency of the composite wave detected by the standing wave detection unit, the direct current component is removed, Fourier transform is performed, and a distance spectrum calculation unit that obtains a distance spectrum,
From the distance spectrum, the distance spectrum at the time of reference is subtracted, the difference between the distance spectra is calculated, and a difference detection unit that obtains this difference distance spectrum over time,
An amplitude of the differential distance spectrum is monitored based on a change in the dielectric constant of the dielectric member, and a monitoring unit that monitors an increase or decrease in the dielectric constant of the dielectric member based on the change in the amplitude. ,
A detection unit that detects the charged state of the dielectric member when the monitoring unit detects an increase or decrease in the dielectric constant of the dielectric member;
Have a,
The dielectric member is a laminated body of a radio wave absorbing part made of a radio wave absorbing material and a dielectric part made of a dielectric material, and is arranged with the dielectric part as a charging measurement side. ..

Another charged state detection device according to the present invention is
The frequency-swept radio wave is transmitted to the outside, the reflected wave reflected by the dielectric member is detected at two points separated by a certain distance based on the transmission wavelength, and the standing wave synthesized from the transmission wave and the reception wave is detected. A standing wave detector that detects
From the intensity distribution of the frequency of the composite wave detected by the standing wave detection unit, the direct current component is removed, the Fourier transform is performed, and the distance spectrum calculation unit that obtains the distance spectrum at constant sampling times,
From the distance spectrum, by subtracting the distance spectrum at the time of the previous sampling or a predetermined number of times, the difference between the distance spectra is calculated, and a difference detection unit that obtains this difference distance spectrum over time,
An amplitude of the differential distance spectrum is monitored based on a change in the dielectric constant of the dielectric member, and a monitoring unit that monitors an increase or decrease in the dielectric constant of the dielectric member based on the change in the amplitude. ,
A detection unit that detects the charged state of the dielectric member when the monitoring unit detects an increase or decrease in the dielectric constant of the dielectric member;
Have a,
The dielectric member is a laminated body of a radio wave absorbing part made of a radio wave absorbing material and a dielectric part made of a dielectric material, and is arranged with the dielectric part as a charging measurement side. ..

In this case,
The monitoring unit can obtain the permittivity by the change in the amplitude of the differential distance spectrum, and can obtain the increase or decrease in the static electricity amount of the dielectric member from the change in the permittivity.

Also, the charged state detection device,
Further, it is possible to have a distance calculation unit that obtains the distance to the dielectric member based on the distance component of the differential distance spectrum.

The earthquake prediction method according to the present invention uses the detection device for the charged state,
Providing the dielectric member on the ground surface,
The feature is that it predicts an earthquake by detecting the charged state on the ground surface.

The method of predicting a lightning strike according to the present invention uses the detection device for the charged state,
Providing the dielectric member on the ground surface,
It is characterized by detecting a lightning strike by detecting the charged state on the ground surface.

The method of predicting electrostatic discharge according to the present invention uses the detection device for the charged state,
It is characterized in that the dielectric member is provided inside a vehicle, and electrostatic discharge of the vehicle driver or an occupant is predicted based on a charged state of the dielectric member.

According to the present invention, a radio wave is applied to the charging measuring unit on the ground surface, and the change in the dielectric constant in the charging measuring unit is measured from the differential distance spectrum of the standing wave radar. At this time, if there is an increase or decrease in the amount of static electricity in the charge measuring unit on the ground surface, this appears as a change in the dielectric constant. On the other hand, the amount of static electricity on the ground surface changes before the earthquake or lightning strike. Therefore, when this increase/decrease in the dielectric constant is detected, it is due to the increase/decrease in the amount of static electricity, so it is used for prediction of an earthquake or lightning strike. Therefore, when predicting an earthquake or lightning strike, it is not necessary to previously install a large-scale device on the surface of the earth or in the ground. In addition, a standing wave detector is installed in the vehicle to measure the amount of charge on the occupant such as the driver to predict the possibility of electrostatic discharge when the occupant touches the door knob when getting off the vehicle. Therefore, when this is predicted, electrostatic discharge can be prevented by issuing an alarm or the like.

It is a figure which shows the use condition of the detection apparatus of the charged state on the ground surface of embodiment of this invention. 2A is a diagram schematically showing the relationship with the occurrence of an earthquake when the charged state of the surface of the dielectric member 102 installed on the ground surface is detected, and FIG. 2B is the dielectric member 102. FIG. 6 is a diagram schematically showing the relationship with the occurrence of a lightning strike when the charged state of the surface of the is detected. It is a figure which shows the state detection apparatus by the standing wave radar of 1st Embodiment of this invention. It is a figure which shows the state detection apparatus by the standing wave radar of 2nd Embodiment of this invention. It is a figure which shows the basic composition of a standing wave radar. It is a figure which shows the wavelength of a transmission wave. It is a figure which shows the power of a synthetic wave. It is a figure after Fourier transformation. It is a figure which shows the power of a synthetic wave. It is a figure which shows the basic composition of the standing wave radar with respect to several targets. It is a spectrum figure which shows the target component pa (fd, 0). It is a wave form diagram which shows the structure of a difference detection part. It is a figure which shows the distance spectrum in case of two targets. It is a figure which shows the true number part and imaginary number part of the spectrum of a synthetic wave. It is a schematic diagram which shows a spherical radiation wave front. It is a typical perspective view explaining an electromagnetic horn. It is a schematic diagram which shows the flatness of the wavefront radiated by the electromagnetic horn. It is a figure which shows the use condition of the detection apparatus of the charging state which concerns on other embodiment of this invention. It is a figure which shows the use condition of the detection device of the charging state which concerns on other embodiment of this invention.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a diagram showing a usage state of a detection device for a charged state on the ground surface according to the present embodiment. A radio wave is emitted from the detector 100 toward the dielectric member 102 installed on the ground surface 101, a standing wave is detected, and the dielectric constant of the dielectric member 102 is measured.

The electric wave is reflected by the conductor, but in the dielectric, the reflectance of the electric wave differs depending on the permittivity. The higher the permittivity, the more the electric wave is reflected, and the object having the lower permittivity transmits the electric wave. Further, when static electricity is generated on the surface of this dielectric, the reflectance of radio waves varies depending on the amount of static electricity. That is, when the amount of static electricity on the surface of the dielectric member 102 installed on the earth's surface 101 is small, the reflection of radio waves is small, and when the amount of static electricity is large, strong reflection of radio waves is generated like a conductor. This dielectric holds static electricity and is easily charged. Since the charging situation is similar to the phenomenon of electronic polarization of permittivity, the charging situation and amount can be detected by irradiating radar radio waves and detecting the reflection level thereof. ..

In the present invention, radio waves are applied to the measurement unit (dielectric member 102) on the ground surface, and the change in the dielectric constant in the measurement unit on the ground surface is measured from the differential distance spectrum of the standing wave radar. At this time, if there is an increase or decrease in the amount of static electricity in the measurement portion on the ground surface, this appears as a change in the dielectric constant. On the other hand, the amount of static electricity on the ground surface changes before the occurrence of an earthquake or lightning strike. Since the permittivity changes according to the increase or decrease in the static electricity amount, an earthquake or lightning strike can be predicted by detecting the change in the permittivity.

Next, the detector 100 of the dielectric constant of the ground surface by the standing wave radar will be specifically described. FIG. 3 is a block diagram of a dielectric constant detecting device by a standing wave radar including the detector 100. The standing wave detection unit 2 is configured as a standing wave radar module, and the standing wave radar module is provided with a 24 GHz high frequency transmission/reception unit 4. The 24 GHz high frequency transmission/reception unit 4 is a module in which a 24 GHz band VCO (voltage controlled oscillator) and the planar antenna 3 are integrated. Then, the transmitting/receiving unit 4 transmits the radio wave 1 from the planar antenna 3 by the VCO, and the antenna 3 detects the reflected wave from the object to be measured. The transmitter/receiver 4 has two built-in detectors 5a and 5b, and the detectors 5a and 5b detect a transmitted wave and a received wave.

When the radio wave 1 is transmitted from the antenna 3, if there is a reflecting object, the reflected wave returns to the antenna 3, and waves having the same frequency but different traveling directions are overlapped with each other to generate a standing wave that is a composite wave. A transmission signal (traveling wave) and a reception signal (reflected wave) are mixed on the line connecting the VCO and the antenna 3 and on the antenna feeding part, and a standing wave is generated by combining them. In this case, the sweep voltage to be supplied to the VCO needs to be kept constant at least for the time until the transmitted radio wave is reflected back by the object to be reflected and returned. Therefore, the sweep voltage needs to be changed stepwise. There is. Then, the signal levels of the mixed waves for a plurality of frequencies are detected by the detectors 5a and 5b by controlling the VCO and sequentially switching the frequencies. The detectors 5a and 5b detect the power of the transmitted wave, the power of the reflected wave, and the component generated by the standing wave. The obtained detected signal is amplified by the operational amplifiers 6a and 6b in a required band of 400 kHz or less, and is input to the signal processing unit 8.

The signal processing unit 8 configured as a radar control module board generates a frequency control voltage FM-modulated by the modulation signal generation unit 10. This frequency control voltage is converted into an analog signal by the DA converter 9, and further, this frequency control signal is amplified through the operational amplifier 7 and then input to the control input of the VCO of the 24 GHz high frequency module 4. This frequency control signal causes the VCO to sweep the frequency of the transmitted radio wave.

In the signal processing unit 8, the detection signal amplified by the operational amplifiers 6a and 6b is input to the AD conversion unit 11 and then input to the distance spectrum calculation unit 12. The distance spectrum calculation unit 12 removes the DC component from the intensity distribution of the frequency of the composite wave detected by the standing wave detection unit 2 and performs Fourier transform to obtain the distance spectrum. This distance spectrum is input to the difference detection unit 13. The difference detection unit 13 subtracts the distance spectrum at the reference time from the distance spectrum, calculates the difference of the distance spectrum, and obtains this difference distance spectrum over time. This difference distance spectrum is input to the distance calculation unit 14. Then, the distance calculation unit 14 obtains the distance to the measurement target from the distance component of the difference distance spectrum. Then, the determination unit 15 monitors how the amplitude of the differential distance spectrum changes based on the change in the dielectric constant of the measurement target, and based on the change in the amplitude, the amount of static electricity in the measurement unit (dielectric member 102). Determine the change in.

In the signal processing unit 8, the detected signal is converted into a digital signal by the AD conversion unit 11 and then input to the distance spectrum calculation unit 12. In the distance spectrum calculation unit 12, the input signal is a periodic function, and its period is inversely proportional to the distance from the object to be reflected. Therefore, by Fourier transforming this, the frequency that is the reciprocal of the period is obtained. Thus, the distance from this frequency to the object to be reflected can be obtained. Further, based on the phase of the obtained waveform, it is possible to detect the minute displacement information of the object to be reflected. For example, in the case of 24 GHz, the minute displacement has a value obtained by dividing the speed of light by 4πf, and a displacement within a range of about ±3.125 mm can be detected. In this way, by processing the signals detected by the detectors 5a and 5b, the distance from the object to be reflected, the speed and displacement of the object to be reflected are calculated, and the change over time is measured to obtain the object to be reflected. It is possible to detect the condition of the body.

The determination unit 15 detects a change in the moisture content of the measurement target, and outputs the determination result by wire or wirelessly to an external alarm device to issue an alarm signal or to an external display device to display this display. Display on the device.

Next, the configuration of the signal processing unit 8 will be described in more detail. As shown in FIG. 5, the standing wave is generated by the interference between the transmission wave VT generated from the VCO that is the signal source and the reflected waves VR1, VR2, VR3,... VRn from each target. By using this standing wave, the standing wave radar detects the amount of moisture of the measurement target and measures the distances d1, d2, d3... dn to each measurement target.

The transmission wave (traveling wave) is represented by the following formula 1 where A is the amplitude of the signal source, f(t) is the frequency, and c(3×10 ⁸ m/s) is the speed of light. However, the frequency f(t) is represented by f0 and fd as shown in FIG.

If the distance of the kth target is dk, the ratio of the magnitude of the reflected wave to the transmitted wave at any point on the x axis is γk (the magnitude of the reflection coefficient), and the phase difference is φk (the phase of the reflection coefficient). The reflected wave from the target can be expressed by Equation 2 below.

Since the detection output detected from the antenna is a composite wave, the amplitude Vc is represented by the following formula 3, and the power is the square of the amplitude, so the power of the composite wave is represented by the following formula 4.

Since the magnitude of the transmitted wave is orders of magnitude greater than the magnitude of the reflected wave, γk is much smaller than 1. Therefore, by substituting the equations 1 and 2 into the equation 4 and taking an approximate value, the following equation 5 is obtained.

In the mathematical expression 5, the first term in {} indicates the power of the transmitted wave, the second term indicates the power of the reflected wave, and the third term indicates the change amount of the power due to the standing wave. The conventional radar receives the reflected wave of the second term and performs signal processing, but in the present invention, the signal of the third term is processed. Therefore, in order to delete the first item and the second item, the composite wave power p(fd, xs) is differentiated by fd to remove the first item and the second item.

Here, assuming that the number of targets (reflectors) is 1, n=1 is substituted into Equation 5 to obtain Equation 6 below. When this equation 6 is graphed, it becomes as shown in FIG. 7. That is, the power of the composite wave is the sum of the fixed value 1+γ ² and the periodic function. In FIG. 7, the frequency of the periodic function (the reciprocal of the period) is c/2d, and the component of the distance d is included. Therefore, if the frequency is obtained from the cycle, the distance d will be obtained. When the DC component 1+γ ² is removed from Formula 6 and Fourier transform is performed, a distance spectrum P(x) is obtained as shown in FIG.

First, variables are replaced with respect to the Fourier transform formula shown in the following formula 7, and further Fourier transform is performed with the observation position as the origin, and the distance spectrum shown in the following formula 8 is obtained. However, Sa(z)=sin(z)/z. It should be noted that in Equation 8, the direct current component is not cut. When a function with a period is subjected to Fourier expansion, it is decomposed into a DC component and a vibration component (sin, cos) contained in the function. The distance spectrum is represented by the following Equation 8 according to its formula.

Note that A ² f _w (1+Σγ _k ² )Sa(2πf _w /c)x) in Expression 8 is a DC component, but this DC component is removed by a capacitor in an actual circuit.

The distance spectrum P(x) expressed by the last expression of the mathematical expression 8 is shown in the graph of FIG. Then, the direct current component of the first item in {} of the mathematical formula 8 is removed, the third item is removed by converting the cos component into a complex sine wave (analysis signal), and the second item of the standing wave component is removed. The components can be extracted. However, as shown by the broken line in FIG. 8, the signal on the imaginary side leaks into the component of the second item in {} of Expression 8. In other words, the standing wave component in this portion has a value in which the signal on the imaginary number side leaks.

In order to solve such a problem, for example, as shown in FIG. 10, when a signal in which a transmitted wave and its reflected wave are combined is detected, the wavelength of the transmitted wave is set to λ, and the signal is separated by λ/8. The signal level can be detected at the two points. In other words, when the traveling direction of the radar is taken as the x-axis, the antenna receives reflected waves from n (n is a natural number, only two in the figure) targets that are to-be-reflected objects, and the antenna receives the reflected waves together with the transmitted wave. , Two power detectors which are separated by λ/8 in the x-axis direction, and detect the detected signals. At this time, if the power levels detected by these two detectors are p(f _d , x ₁ ) and p(f _d , x ₂ ), the output of the detector placed at the position of x ₁ =0 will be detected. Substituting x ₁ =x _s =0 into the mathematical expression 5 indicating power, it is obtained as p(f _d , 0) shown in the following mathematical expression 9, and the output of the detector placed at the position of x ₁ =−λ/8 Is obtained by substituting x ₂ =x _s =−λ/8 into Expression 5 indicating the detected power, and obtaining p(f _d , −λ/8) shown in Expression 9 below. As shown in Equation 9, by detecting a standing wave at two points separated by λ/8, the standing wave component of the output of the detector placed at each position (0, −λ/8) becomes An orthogonal component of cos and sin is obtained, which makes it possible to eliminate the virtual image signal and eliminate the influence of the signal leaking from the virtual image side. That is, a vector synthesized from orthogonal components of cos and sin (X-axis component and Y-axis component) is an analysis signal. Normally, the signal on the imaginary axis side cannot be measured, but the signal on the imaginary axis side can be measured at the position of −λ/8, and a vector composite signal can be formed. Since the rotational speed of this vector becomes a frequency, this frequency and phase are analyzed in the present embodiment.

When the standing wave component of the output of the detector at the position of x _s =0 in this formula 9 is a and the standing wave component of the output of the detector at the position of x _s =−λ/8 is b, , B are represented by the following mathematical formula 10. Then, by substituting the final expression consisting of the three terms of Expression 8 based on Expression 11 below, Expressions 12 and 13 below are obtained. That is, it becomes possible to replace the X-axis and Y-axis (actual signal, imaginary axis signal) obtained by the mathematical expression 10 with a form converted into an actual signal. Expression 13 exactly expresses the signal in the time direction and the signal on the rotation axis, but it can be seen that, in the end, Expression 13 can calculate the rotating analytic signal.

P _{DC on} the right side of Expression 12 is a DC component, and m(f _d )cos(θ(f _d )−4π(f ₀ +f _d )/c·x _s ) is a standing wave component that changes periodically. is there. As described above, the standing wave component is a composite component a+jb of the component a at the position of x _s =0 and the component b at the position of x _s =−λ/8, which is an orthogonal component of sin and cos. By combining the analytic signals from a and b, the influence of unnecessary signals (signals leaking from the imaginary number side shown in FIG. 9) is removed. Therefore, by analyzing this value (the signal of Expression 13), the target component p _a (f _d , 0) shown in FIG. 11 is obtained.

Thus, in the analytic signal of Expression 13, the detected signal intensity changes depending on the magnitude of the reflection coefficient γk. In other words, if the temporal transition of the signal intensity of the analytic signal is measured, one of the causes when the intensity changes is that there is a change in the reflection coefficient γk. That is, a change in the signal intensity caused by a change in γk (magnitude of the reflection coefficient) of each frequency in the frequency distribution indicates a change in the charged state of the measurement target.

The reflection coefficient γ at the interface between two substances having different permittivities is represented by the following formula 14 when the permittivities are ε1 and ε2.

As described above, the reflection intensity at the boundary surface is determined by the difference in the specific dielectric constants of the respective media forming the boundary surface, and the polarity of the reflected waveform is also determined by the magnitude relationship of the relative dielectric constants. Therefore, the reflection intensity of the radio wave varies depending on the magnitude of the reflection coefficient γ, and the reflection coefficient γ varies depending on the dielectric constant. Therefore, the reflection intensity changes due to the change of the substance on the reflection surface.

Therefore, the reflection coefficient is obtained by the above equation 13 and the dielectric constant is obtained by the equation 14. This dielectric constant is a measured value indicating the charged state on the ground surface.

As described above, the charged state of the dielectric member 102 can be detected by the change in the amplitude intensity of the distance spectrum calculated by the distance spectrum calculation unit 12. However, in this distance spectrum, there is no change in the amount of static electricity. The distance spectrum of the standing wave caused by the reflected wave from is included. Therefore, the difference detection unit 13 deletes the reference distance spectrum from the measured distance spectrum to calculate the difference distance spectrum. FIG. 12A shows the distance spectrum P(x) obtained by the distance spectrum calculation unit 12. This measurement result includes the one caused by the reflected wave from the environment without the measurement unit containing static electricity. Therefore, the distance spectrum obtained at the specific reference time is set as P ₀ (x), and the distance spectrum P ₀ (x) at the reference time is subtracted from the distance spectrum P(x) obtained at each subsequent sampling time. That is, −P ₀ (x) shown in FIG. 12B is added to the distance spectrum P(x) obtained at each sampling time. Therefore, when there is no electrostatic charge, the difference detection unit 13 obtains a 0 signal as shown in FIG. Therefore, when static electricity is charged in the measurement unit at a certain sampling time, the amplitude of the distance spectrum of the charge appears as shown in FIG. When the reference spectrum −P ₀ (x) of FIG. 12( b) is added to the distance spectrum at this sampling point, as shown in FIG. 12( e ), P(x)−P ₀ (x) of A distance spectrum is obtained, and only the amplitude of the peak intensity due to charging appears in this distance spectrum. In this way, the difference detection unit 13 determines the difference between the distance spectra to reduce the influence of reflection from the environment of the measurement unit and obtain the intensity of the amplitude of the distance spectrum due to the change in charging. You can

The distance spectrum when measured is two, as shown in FIG. _13, the power p of _{x s = 0 (f d,} 0) and _x s = _-λ / 8 power p _(f d of - The frequency corresponding to the distance is obtained by removing the DC component from the combined wave with λ/8) and performing the Fourier transform, and the distances d ₁ and d ₂ are obtained.

FIG. 14 is a diagram showing the true spectrum and the imaginary spectrum of the composite wave. The radio wave velocity c is about 300,000 km/sec. When the frequency sweep of the transmitted wave is performed with a width of 75 MHz (fw), the wavelength of 75 MHz is c/fw=4 m. However, the sweep for sampling the waveform is 4 m for the round trip, so the distance is half of that, 2 m. This 2 m is called one cycle. Therefore, when 20 m is measured with a sweep width of 75 MHz, 10 cycles are measured. Assuming that the sweep time is 256 μs, the frequency of the observed waveform is 10/256 μs=39 kHz. Similarly, when 200 m is measured, since it is 100 cycles, 100/256 μs=390 kHz. Then, the frequency level of the detected spectrum shown in FIG. 14 indicates the intensity of reflection, and the frequency is replaced by the distance. Therefore, as shown in FIG. 13, when a peak appears at 39 kHz by Fourier transform, it is understood that it is a reflected wave from a position at a distance d ₁ =10 m, and a peak appears at 390 kHz, It can be seen that it is a reflected wave from a position at a distance d ₂ =100 m. In this way, the detection power pa(fd) of the combined wave of the detector is differentiated to remove the DC component, and the Fourier transform is performed, whereby the distance to the measurement target can be obtained.

When the sweep width is 200 MHz, one cycle is 0.75 m, so 10/0.75=13.3 cycles are observed in the measurement of 10 m, and when the sweep time is 256 μs, 13.3 /256=51.9 kHz. That is, when the sweep width is 200 MHz and the peak appears at 51.9 kHz, the distance to the reflected object is observed to be 10 m. Therefore, the frequency of the detection output can be adjusted by adjusting the sweep width and the sweep time, and the bandwidth is limited by the regulation of the Radio Law, so the sweep time is generally variable. Then, the distance to the reflected object is measured.

Next, the minute displacement measurement will be described. In Equation 8, paying attention to the phase, the phase Ψk for the k-th target Motomari as the angle of the first equation of sin in Equation (11) below 15, since phi _k disappears in variation from the initial phase, the distance d _k When the change amount is Δd _k and the phase change amount is ΔΨ _k , the second formula of Formula 14 is obtained, and this is modified to obtain Formula 16 below.

From this equation 16, a minute displacement of the distance d can be obtained. When the frequency is 24 GHz, it is possible to detect a displacement of ±3.125 mm.

As described above, the distance and the minute displacement of the reflected object can be measured by analyzing the standing wave in which the reflected wave from the reflected object is combined with the transmitted wave. If this measurement result is grasped over time, the distance, speed and displacement of the object to be reflected can be measured, and eventually the movement of the object to be reflected can be measured. In the conventional radar, it is difficult to measure the distance of 1 to 2 m or less, whereas the present invention enables the distance to be measured from a close range close to 0 m to a long range of 200 m. Further, in the case of the present invention, it is possible to detect a minute displacement, and the relative displacement resolution reaches 0.01 mm.

As described above, according to the present invention, when the peak intensity of the distance spectrum shown in Formula 13 changes depending on the magnitude of the reflection coefficient γk and the amount of charge increases in the measurement unit, the permittivity ε of water changes. Since it is high, the measurement principle is to detect water by increasing the reflection coefficient γk shown in Expression 14 and increasing the peak intensity of the distance spectrum. Since the peak intensity is observed in this way, it is easy to detect moisture even when there are a plurality of measurement units. However, if the number of measurement units is large and the distance between the measurement units is short, for example, a plurality (two in the illustrated example) of distance spectra shown in FIG. May not be separated. In this case, it becomes impossible to obtain the phase difference required for measuring the above-mentioned minute displacement for each measurement target. In such a case, the two distance spectra can be separated by applying a bandpass filter.

FIG. 4 is a block diagram showing an embodiment in this case. The difference distance spectrum output from the difference detection unit 13 is input to the bandpass filter 16. The band-pass filter 16 is a notch-type band-pass filter that outputs a signal having the minimum gain from the difference distance spectrum of the difference detecting unit 13 at an intermediate frequency of the center frequencies corresponding to the plurality of peak positions. The differential distance spectrum output from the bandpass filter 16 becomes a plurality of differential distance spectra separated between peak positions. Each of these difference distance spectra is input to the distance calculation unit 14, and it becomes possible to obtain a minute displacement from the phase difference.

Next, an operation of the apparatus for detecting a charged state by the standing wave radar according to the embodiment of the present invention will be described together with usage examples. First, the detector 100 is installed toward the charge measuring unit (dielectric member 102). Then, the standing wave detection unit 2 detects a standing wave that is a composite wave of the transmitted wave and the received wave. The detection signal of this standing wave is input to the distance spectrum calculation unit 12 via the AD conversion unit 11, and the distance spectrum is calculated. Then, from this distance spectrum, the difference detection unit 13 obtains a difference distance spectrum. The distance calculator 14 calculates the distance between the sensor and the measurement target from the difference distance spectrum as described above. As a result, it can be seen that the peak position of this difference distance spectrum is the distance (for example, 2.5 m) between the sensor and the measurement target, as shown in FIG. Then, the determination unit 15 monitors the temporal change of the peak intensity of the differential distance spectrum having the peak position at the position of 2.5 m. Then, when the peak intensity is increased, the determination unit 15 causes the change in the dielectric constant due to the change in the charge amount (static amount) of the dielectric member 102 to be measured and the increase in the reflection intensity. Can be detected, and the time point when the peak intensity increases can be determined to be the time point when the charge amount increases.

Further, when the measurement unit (dielectric member 102) is at the distance d1 and the distance d2, radar waves are radiated from the sensor to these measurement targets, and the reflected waves from the measurement targets (d1, d2) are reflected by the sensor. Is detected. Then, the difference detection unit 13 sets the distance spectrum at a specific time point as the distance spectrum at the reference time with respect to the distance spectrum of the distance d1, and obtains the distance spectrum at every fixed sampling time point (FIG. 12(a)). Then, the distance spectrum at the reference time (FIG. 12B) is subtracted from this to calculate the differential distance spectrum (FIG. 12C). As a result, if there is no change from the distance spectrum P0(x) at the reference time, the difference distance spectrum obtained at each sampling time becomes 0 as shown in FIG. 12(c). Then, as shown in FIG. 12D, when static electricity is present in the dielectric member 102 of the measurement unit, a distance spectrum P(x) including a spectrum caused by the static electricity is obtained. As a result, as shown in FIG. 12E, only the distance spectrum due to static electricity appears in the differential distance spectrum P(x)-P0(x). Therefore, the determination unit 15 can monitor the difference distance spectrum and determine that the time when the difference distance spectrum becomes 0 is the time when the drying is completed. In this way, the state of the amount of static electricity of the measurement unit (dielectric member 102) can be individually detected.

In the present embodiment, as described above, the detector 100 detects the state of the amount of static electricity of the dielectric member 102. Next, an application example of this static electricity amount (charge amount) detection will be described. First, an example in which the apparatus for detecting a charged state by the standing wave radar according to the present invention is used for earthquake prediction will be described. The ionosphere is a layer existing in the upper layer of the atmosphere so as to surround the earth, and is a region where ions and electrons are present due to ionization of molecules and atoms by ultraviolet rays or X-rays. The ionosphere is normally in a stable state, but the charge separation state changes before the earthquake. This change in the ionosphere is due to the ground rubbing that occurs before the earthquake, and the ions are ejected in the ground rubbing. In other words, when ions are emitted due to the rubbing of the ground, the charge separation state changes in the ionosphere facing the ground according to the charge separation state of the ground. Conventionally, by measuring the state of electric charges in this ionosphere, it has been attempted to use this for earthquake prediction. On the other hand, in the present invention, by detecting the charge charging state of the dielectric member 102 installed on the ground surface, this is utilized for earthquake prediction. As a sign of an earthquake, when the ground rubs against each other, electric charges are first generated on the ground surface. The charges generated on the surface of the earth accumulate on the surface of the dielectric member 102, and the surface of the dielectric member 102 is charged. Therefore, the charge level of the dielectric member 102 is measured by irradiating the dielectric member 102 with radar radio waves. This makes it possible to estimate the risk of an earthquake.

In the present invention, as shown in FIG. 1, instead of irradiating the radar radio wave to the ionosphere, it irradiates the dielectric member 102 installed on the ground surface 101. In order to irradiate the radar toward the ionosphere, a high-power radar transmitter capable of searching a long distance is required. However, since the present invention targets the dielectric member 102 installed on the ground surface 101, it has a small output. You can predict earthquakes with radar. Also, when the ground rubs as a sign of an earthquake, charges are first generated on the surface of the earth, but rather than when measuring the charge separation situation in the ionosphere that occurs with a delay corresponding to the generation of charges on the surface of the earth. It is possible to detect the sign of an earthquake earlier by measuring the change of the charged state on the ground surface. In the ionosphere, the charge density of the region ionized by sunlight changes. That is, the charge density increases with sunrise, and the activity becomes dormant at sunset. However, when rubbing on the ground surface, which is known as a sign of an earthquake, ions are generated, and impulse ions are emitted even at night. Therefore, the charged state on the ground surface is disturbed. Therefore, it is possible to predict an earthquake with higher accuracy by using the charged state on the surface of the earth as an index of the earthquake rather than the ionosphere.

In this way, when an abnormal change in the charged state of the dielectric member 102 on the surface of the earth is detected, it can be used for earthquake prediction as a sign that an earthquake will occur in the near future. FIG. 2A is a diagram schematically showing the relationship with the occurrence of an earthquake when the charged state of the surface of the dielectric member 102 installed on the ground surface is detected. In the pre-earthquake stage, when the charge amount of the dielectric member 102 gradually increases and the charge amount increases with a certain degree of inclination, the possibility of occurrence of an earthquake becomes extremely high. When the increase in the charge amount of the dielectric member 102 on the ground surface exceeds a predetermined threshold value, or when the increase rate of the charge amount exceeds a predetermined threshold value, an earthquake may occur in the near future (such as hours or days). It is reasonable to predict that will occur.

In addition, the threshold value of the charge amount or the predetermined threshold value of the charge amount increasing rate with high possibility of occurrence of an earthquake can be obtained by machine learning of artificial intelligence. In this case, data regarding the dielectric constant of the dielectric member 102 detected by the detector 100 can be statistically analyzed by supervised learning to predict future unknown data. As described above, when the ground friction, which is a sign of an earthquake, occurs in the electrostatic charge transition of the dielectric member 102. Therefore, by detecting this electrostatic charge transition by the detector 100, the electrostatic charge when the earthquake actually occurs is detected. Data that compares the threshold value of the amount and/or the increasing rate of the charge amount (the inclination angle in FIG. 2A) with the presence or absence of an earthquake is acquired, and the obtained data is statistically analyzed. Then, a data transition pattern is learned in advance, and by daily monitoring of the charging state by the detector 100, in the data transition pattern obtained by machine learning, the data pattern at the initial stage of charging when an earthquake occurs When a data transition that matches the previous stage transition data) is measured, an earthquake prediction warning is output.

Next, an example will be described in which the apparatus for detecting a charged state by the standing wave radar of the present invention is used for predicting a lightning strike. The ascending air currents containing water vapor on the ground are cooled by the cold air in the sky to form fine ice crystals. These crystals collide with each other in the air current and become a thundercloud while separating into positive and negative charges. This thundercloud is formed by a plurality of cells, and at the same time, a positive charge (confined charge) having a polarity opposite to that of the cloud base is induced in the overhead line or ground. In this state, when the electric field strength reaches the limit, discharge occurs between positive and negative charges (between cells) in the cloud (between clouds), and thus a discharge in the cloud (between clouds) is frequently generated. The frequency of intra-cloud (inter-cloud) discharges is high, and the electric charges of the thundercloud are extinguished by repeated discharges.

On the other hand, when a lightning strike is viewed over time, a pioneering discharge (stepped leader) repeatedly occurs from the cloud bottom toward the ground, and the insulation of the atmosphere is destroyed. Then, when the precursory discharge approaches the ground, an upward discharge (leader) is generated from the ground side, and a large amount of electric charges are injected into the atmosphere that has been dielectrically broken down by the precursory discharge and the upward discharge, and a lightning strike occurs.

As shown in FIG. 2B, when a lightning strike is about to occur, the charge amount changes in units of several minutes. Then, when the charge amount rapidly increases and the charge amount exceeds a predetermined threshold value or the increase rate of the charge amount exceeds a predetermined threshold value, a lightning strike occurs. However, when the rate of increase of the charge amount is low (when the inclination angle is small), the lightning does not occur and the electric charge disappears. Therefore, machine learning of artificial intelligence is used to learn charge transition data that changes rapidly in steps in a short time on the ground surface directly below the thundercloud, and is classified into patterns by statistical processing. When the detector 100 monitors the charged state of the dielectric member 102 on the surface of the earth, when transition data that matches the lightning strike pattern (the pattern immediately before the lightning strike occurs) obtained by this statistical analysis is measured. , Outputs an alarm to predict the occurrence of lightning strikes. Also in the case of this lightning strike prediction, it is rational to measure the charge amount of the dielectric member 102 installed on the ground surface and predict the lightning strike based on the change in the charge amount.

In the present embodiment, an earthquake or a lightning strike is predicted when the dielectric member 102 on the ground surface 101 is charged due to the ground rubbing or the precursory discharge of the lightning strike. However, the dielectric member 102 does not necessarily need to be installed on the ground surface 101. For example, the dielectric member 102 may be installed at a high position slightly apart from the ground surface 101, such as an electric pole, a traffic signal, or an upper portion of a street light. The electric charges generated from the ground are not limited to the ground surface 101, but are charged to a position slightly above the ground surface 101. Therefore, for example, the dielectric member 102 and the detector 100 may be installed above a telephone pole, a traffic light, or a street light provided all over Japan, and the charge amount of the dielectric member 102 may be monitored. As described above, when the dielectric member 102 and the detector 101 are provided at a high position such as a power pole, a traffic light, or a street light, instead of the ground surface 101, the installation of the device does not interfere with the movement of a person. The dielectric member 102 and the detector 101 as described above are preferably installed at as many positions as possible on the ground surface 101. The position where the amount of charge should be monitored is preferably set to have an interval of 10 m to 1 km, for example, but these devices are intensively installed in places where earthquakes or lightning strikes frequently occur. It may be done. As described above, in the present invention, the charge measuring unit is installed on the ground surface to detect the charged state on the ground surface. However, in the case of the ground surface in the present invention, the charge generated on the ground can be charged from the ground. It refers to the area up to the height, and is not limited to the ground or the vicinity thereof.

In the present embodiment, a radio wave is transmitted from the antenna 3 and a standing wave is synthesized by detecting reflected waves at two points. When an electromagnetic horn is used as the antenna 3, the phases of standing waves can be neatly aligned. FIG. 15 is a diagram showing a radiation surface formed by connecting surfaces having the same phase in the radiation direction of the radio wave emitted from the transmission point. Thus, the emitting surface is spherical. As shown in this figure, the phase at the edge portion is delayed and propagated with respect to the phase at the center in the radial direction. Therefore, when viewed from the front where the radio waves are transmitted, the phases of the radio waves are not aligned and a phase shift occurs, and the accuracy of phase shift measurement cannot be obtained.

On the other hand, by using the electromagnetic horn 120 shown in FIG. 16, the radiation surfaces having the same phase can be made flat. FIG. 17 is a schematic sectional view taken along line 16-16 of FIG. The electromagnetic horn 120 is provided with a horizontally long trumpet-shaped recess 121, and two antennas 122 and 123 are provided at the tip of the inclined surface of the recess 121 (bottom of the recess 121) so as to be separated in the horizontal direction. ing. The patch antenna 122 is a transmitting side antenna, and the patch antenna 123 is a receiving side antenna. The radio wave emitted from the antenna 122 propagates forward while being reflected by the slope of the recess 121 of the electromagnetic horn 120. That is, the trumpet-shaped member called an electromagnetic horn is made of a conductive material that reflects radio waves, and when the wavefront of a spherical radio wave is radiated, the wavefront becomes parallel as shown in FIG. Therefore, when this electromagnetic horn is used, radio waves can be radiated so that the phase planes are in phase by utilizing the phenomenon that the wave fronts are parallel. As a result, the phase of the reflected wave can be accurately detected.

However, the conventional electromagnetic horn has a simple conical structure because transmission and reception are performed by one antenna. Therefore, when one patch antenna is used as both the transmitting antenna and the receiving antenna, the center of transmission and reception is different in an ordinary cylindrical or rectangular type horn, the beam shape becomes unbalanced, and the radiation direction shifts left and right. Therefore, there is a possibility that the radiation performance to the front surface is not good.

On the other hand, in the present embodiment, the transmitting antenna 124 and the receiving antenna 125 are provided exclusively. Then, in the direction perpendicular to the direction in which the transmitting antenna 124 and the receiving antenna 125 face each other, the horn slopes facing each other with the antenna 122 sandwiched therebetween form a waveguide structure in which radio waves are reflected. As a result, the phase planes are aligned in the vertical direction of FIG. On the other hand, in the left-right direction (the direction in which the antennas 122 and 123 face each other), the shape of the horn does not surround the four sides. As described above, in this embodiment, the waveguide structure is formed only on one side, and the phase planes in the vertical direction are aligned. That is, radio waves are radiated vertically from the batch antenna 122, and the radiation is radiated forward on the plane radio wave front as shown in FIG. Therefore, the electromagnetic horn 120 shown in FIG. 16 can radiate a radio wave having a planar wavefront forward with high efficiency. The receiving antenna 123 can also receive with high efficiency. That is, it is possible to accurately detect a slight displacement of the waveform of the reflected wave from the target object by transmitting the plane wave whose phases are aligned in a plane.

Next, an example in which the apparatus for detecting a charged state by the standing wave radar of the present invention is used for predicting electrostatic discharge will be described. When driving a car or riding in the passenger seat as an occupant, the person's clothes are rubbed and the person is charged with static electricity. If the passenger tries to get off the vehicle with the static electricity charged, static electricity is generated when the occupant comes into contact with the door handle, which gives the occupant an extremely uncomfortable feeling.

Therefore, the detector 100 as the standing wave detection unit of the present invention is installed inside or on the ceiling of the dashboard in the vehicle, and is configured to radiate radio waves toward an occupant such as a driver. Then, in the same manner as in the first embodiment, the standing wave is detected and the differential distance spectrum is calculated to detect an increase in the static electricity charged on the clothing or the like of the occupant. Then, when the amount of static electricity exceeds a predetermined threshold value, it is predicted that electrostatic discharge occurs when the person touches the door handle. When this prediction is made, the occupant operates the door handle after taking measures to discharge the static electricity charged in the clothes, for example, by issuing an alarm sound. As a result, it is possible to prevent the occurrence of electrostatic discharge when getting off the vehicle.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the dielectric member 103 having a two-layer structure is used as the dielectric member. That is, the dielectric member 103 is composed of a radio wave absorbing section 105 made of a radio wave absorbing material and a dielectric section 104 laminated on the radio wave absorbing section 105. The radio wave absorbing material of the radio wave absorbing unit 105 absorbs the radio wave by converting most of the energy of the incident radio wave into heat energy inside the absorbing unit. Examples of such radio wave absorbing materials include a carbonaceous material having carbon as a main component, a material containing graphite (carbon particles) in expanded polyethylene, a material containing carbon particles in rubber, and the like. The dielectric part 104 is made of a dielectric material such as plastic.

In the charge detection device thus configured, the dielectric member 103 is installed at a position where the charge state should be measured. In the present embodiment, the radio wave absorber 105 is placed on the ground surface 101 with the radio wave absorber 105 facing downward. Therefore, the dielectric portion 104 faces upward of the ground surface. Then, the detector 100 is installed toward the upper surface of the charge measuring unit (dielectric member 103), that is, the upper surface of the dielectric unit 104. Then, the standing wave detection unit 2 detects a standing wave that is a composite wave of the transmitted wave and the received wave. This makes it possible to detect an increase or decrease in the dielectric constant of the dielectric portion 104 of the dielectric member 103, as in the embodiment of FIG.

In the present embodiment, a radio wave (transmission wave) is emitted from the detector 100 to the dielectric part 104, reflected by the dielectric part 103, and the reflected wave enters the detector 100. Then, the radio wave passes through the dielectric section 104, reaches the radio wave absorbing section 105, and is absorbed by the radio wave absorbing section 105. Therefore, the radio wave transmitted through the dielectric part 104 is not reflected toward the detector 100. Therefore, the reflected wave incident on the detector 100 is a highly accurate detection of the amount of electric charge charged on the surface of the dielectric portion 104 that reflects the charged state, and the radio wave that becomes noise reflected by other parts is It does not enter the detector 100. For example, when water is present below the dielectric member 103, and when the dielectric member 102 is formed of only a dielectric material as in the embodiment of FIG. 1, a radio wave transmitted through the dielectric member 102. In addition to the charges on the surface of the dielectric member 102, is reflected by water, and the radio waves reflected by this water become noise and enter the detector 100. However, in the present embodiment, the radio wave that has passed through the dielectric portion 104 is absorbed by the radio wave absorbing portion 105 in this manner, so that the radio wave reflected below the dielectric portion 104 is incident on the detector 00. It never becomes. Therefore, the measurement accuracy of the charge amount is higher than that of the embodiment shown in FIG.

Next, still another embodiment of the present invention will be described with reference to FIG. In the present embodiment, four sides of the charge measuring unit (dielectric member 103) are surrounded by the rectangular-tube-shaped radio wave absorbing unit 106. In the present embodiment, radio waves are absorbed by the lower surface (radio wave absorption section 105) of the dielectric member 103, and radio waves are also absorbed by the sides of the dielectric member 103. Therefore, it is possible to prevent radio waves from entering the dielectric member 103 from the vicinity of the charge measuring unit, and reduce noise caused by this radio wave intrusion. Therefore, only the radio waves reflected by the electric charges charged on the upper surface of the dielectric portion 104 of the dielectric member 103 enter the detector 100. Therefore, the detection of the charged state in the detector 100 becomes more accurate.

In addition, in each of the above-described embodiments, the dielectric members 102 and 103 have a rectangular plate shape, but the shape of the dielectric members is arbitrary. The dielectric member 102 only needs to have a surface shape capable of attaching positive or negative charges among the charges floating above the ground surface in the precursory state of an earthquake. The surface shape of the dielectric member 102 may be a plane, a two-dimensionally uneven shape, or a two-dimensionally arranged pyramid. Further, the dielectric member 103 is arranged such that the electric wave absorbing section 105 is located downward and the dielectric section 104 is oriented toward the electric charges floating on the ground surface. The electric wave absorbing section 105 detects the dielectric section 104 between them. It is placed on the opposite side of the container 100. The surface shape of this dielectric portion 104 is also the same as that of the dielectric member 102, and it is set to a shape capable of being charged. Further, the dielectric member 103 is not limited to the two-layer structure of the dielectric part 104 and the radio wave absorbing part 105, and may have a structure of three or more layers including a metal plate or the like.

According to the present invention, a natural disaster such as an earthquake and a lightning strike can be predicted by simply detecting the charged state on the ground surface with a simple device. INDUSTRIAL APPLICABILITY The present invention can predict an earthquake/lightning strike by installing an inexpensive device (a charging detection device using a standing wave radar) without using an expensive device such as a seismometer. Moreover, when the detector 100 is scanned in the detection direction, the possibility of an earthquake or lightning strike in a wide area can be detected by one device. Therefore, by using the present invention, it is possible to easily predict an earthquake and a lightning strike and reduce damage due to a natural disaster. In addition, the charged state detection device of the present invention can predict and prevent electrostatic discharge when a vehicle is in a vehicle, which is beneficial to the comfort of an occupant while driving a vehicle.

2: Standing wave detection unit 3: Antenna 4: High frequency transmission/reception unit 8: Signal processing unit 100: Detector 101: Ground surface 102, 103: Dielectric member 104: Dielectric member 105, 106: Radio wave absorption unit 120: Electromagnetic horn 122, 123: Antenna

Claims (7)

The frequency-swept radio wave is transmitted to the outside, the reflected wave reflected by the dielectric member is detected at two points separated by a certain distance based on the transmission wavelength, and the standing wave synthesized from the transmission wave and the reception wave is detected. A standing wave detector that detects
From the intensity distribution of the frequency of the composite wave detected by the standing wave detection unit, the direct current component is removed, Fourier transform is performed, and a distance spectrum calculation unit that obtains a distance spectrum,
From the distance spectrum, the distance spectrum at the time of reference is subtracted, the difference between the distance spectra is calculated, and a difference detection unit that obtains this difference distance spectrum over time,
An amplitude of the differential distance spectrum is monitored based on a change in the dielectric constant of the dielectric member, and a monitoring unit that monitors an increase or decrease in the dielectric constant of the dielectric member based on the change in the amplitude. ,
A detection unit that detects the charged state of the dielectric member when the monitoring unit detects an increase or decrease in the dielectric constant of the dielectric member;
Have a,
The dielectric member is a laminated body of a radio wave absorbing part made of a radio wave absorbing material and a dielectric part made of a dielectric material, and is arranged with the dielectric part as a charging measurement side. Charged state detection device. The frequency-swept radio wave is transmitted to the outside, the reflected wave reflected by the dielectric member is detected at two points separated by a certain distance based on the transmission wavelength, and the standing wave synthesized from the transmission wave and the reception wave is detected. A standing wave detector that detects
From the intensity distribution of the frequency of the composite wave detected by the standing wave detection unit, the direct current component is removed, the Fourier transform is performed, and the distance spectrum calculation unit that obtains the distance spectrum at constant sampling times,
From the distance spectrum, by subtracting the distance spectrum at the time of the previous sampling or a predetermined number of times, the difference between the distance spectra is calculated, and a difference detection unit that obtains this difference distance spectrum over time,
An amplitude of the differential distance spectrum is monitored based on a change in the dielectric constant of the dielectric member, and a monitoring unit that monitors an increase or decrease in the dielectric constant of the dielectric member based on the change in the amplitude. ,
A detection unit that detects the charged state of the dielectric member when the monitoring unit detects an increase or decrease in the dielectric constant of the dielectric member;
Have a,
The dielectric member is a laminated body of a radio wave absorbing part made of a radio wave absorbing material and a dielectric part made of a dielectric material, and is arranged with the dielectric part as a charging measurement side. Charged state detection device. The said monitoring part calculates|requires a dielectric constant from the change of the amplitude of the said difference distance spectrum, and calculates|requires increase/decrease of the static electricity amount of the said dielectric material member from this change of a dielectric constant. Charged state detection device. 4. The charged state detection device according to claim 1, further comprising a distance calculation unit that calculates a distance to the dielectric member based on a distance component of the difference distance spectrum. The charged state detecting device according to any one of claims 1 to 4 is used,
Providing the dielectric member on the ground surface,
An earthquake prediction method characterized by detecting an electrostatic charge on the ground surface to predict an earthquake. The charged state detecting device according to any one of claims 1 to 4 is used,
Providing the dielectric member on the ground surface,
A method of predicting a lightning strike, which comprises detecting a charged state on the ground surface to predict a lightning strike. The charged state detecting device according to any one of claims 1 to 4 is used,
A method of predicting electrostatic discharge, characterized in that the dielectric member is provided inside a vehicle, and electrostatic discharge of the vehicle driver or an occupant is predicted based on a charged state of the dielectric member.

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