Measuring system for measuring gas shock wave velocity and measuring method thereof

Abstract

The invention relates to a measuring system for measuring gas shock wave velocity and a measuring method thereof. The measuring system for measuring the gas shock wave velocity comprises a microwave source assembly and a gas shock wave velocity measuring assembly, wherein the microwave source assembly comprises N single-frequency continuous wave microwave sources with different frequencies; the power combiner is used for combining the microwaves; the power divider is used for carrying out power distribution on the microwaves and outputting two paths; the circulator is provided with three ports, the first port receives the microwaves of the power divider, the second port outputs the microwaves to the antenna and receives microwave signals returned by the antenna, and the microwave signals are transmitted to the frequency mixer through the third port; the antenna is used for directionally transmitting microwaves to a to-be-detected target and receiving returned microwave signals; and the frequency mixer receives the microwave signal output by the power divider, receives the microwave signal returned by the circulator from the target to be measured, and performs frequency mixing to obtain a Doppler frequency shift signal. According to the measurement system, multi-wavelength continuous microwave interference measurement is adopted, and continuous, high-time-resolution and long-distance measurement of the gas shock wave speed can be achieved.

Description

Technical Field

[0001] This invention relates to the field of gas shock wave measurement technology, and more specifically, to a measurement system and method for measuring the velocity of gas shock waves. Background Technology

[0002] Explosions of explosives, highly explosive chemicals, and highly explosive gases generate powerful gas shock waves. Measuring the velocity of these gas shock waves provides crucial experimental data for research in detonation shock wave physics, explosion damage assessment, gas detonation, and shock protection. This data also allows for the verification of relevant theories and provides a basis for weapon design and shock wave protection design.

[0003] Traditional shock wave velocity testing methods primarily employ electrical probes, optical probes, pressure sensors, and strain sensors to obtain the arrival time of the shock wave at various locations. Sensors are placed at different distances from the explosion source, and the distances between these points are measured before the experiment. During the experiment, as the air shock wave arrives at each sensor location sequentially, the sensors respond and output signals. After transmission and conditioning, the time difference between each signal is measured using an oscilloscope or time interval measuring instrument. Finally, the average velocity of the air shock wave propagating between each point is obtained by dividing the distance between each point by the time difference between the signals. The main drawbacks of this method, which uses various sensors to measure distances and time intervals to obtain shock wave velocity, are: the number of sensors limits the acquisition of velocities at only a limited number of points; each velocity value is an average velocity over a given period, not an instantaneous velocity; furthermore, sensor response time and the interpretation of signal start points introduce significant measurement errors; it cannot achieve continuous measurement of gas shock wave velocity; and it suffers from low time resolution and short distance limitations.

[0004] Existing patent: CN102944696B, Chirped Fiber Bragg Grating Sensor and Processing Method, utilizes the characteristic that when a detonation wave / shock wave acts on a chirped fiber Bragg grating, the length of the fiber Bragg grating decreases, thereby weakening the amplitude of the returned signal light, to continuously measure the velocity of the detonation wave or shock wave. However, due to manufacturing limitations, chirped fiber Bragg gratings are generally very short, resulting in the ability to measure only the continuous velocity of the shock wave over a relatively short distance. Furthermore, data processing requires fitting, and the selection of the objective function for fitting can introduce significant errors.

[0005] The literature (Gene H. McCall, Wayne L. Bongnianni, and Gilbert A. Miranda. Microwave interferometer for shock wave, detonation, and material motion measurements. Rev. Sci. Instrument[J], 1985, 56(8): 1612~1618.) introduces the use of microwaves propagating in a micro coaxial line. When the shock wave propagates along the micro coaxial line, the microwave signal is continuously reflected at the position where the wavefront arrives. This signal beats with the reference signal, and the shock wave velocity is obtained from the beat frequency signal. However, it is only applicable to measuring the velocity of shock waves in linear waveguides. In addition, its long transmission lines are susceptible to electromagnetic interference.

[0006] Therefore, when it is necessary to measure the strong gas shock waves generated after the explosion of explosives, explosive chemicals, explosive gases, etc., there is an urgent need to develop a system and method that can realize continuous measurement of gas shock waves. Summary of the Invention

[0007] The technical problem to be solved by this invention is how to achieve continuous measurement of gas shock wave velocity with high time resolution and long distance.

[0008] To solve the above-mentioned technical problems, according to one aspect of the present invention, a measurement system for measuring the velocity of a gas shock wave is provided, wherein the gas shock wave to be measured is a moving target to be measured, and the measurement system includes: a microwave source assembly comprising N single-frequency continuous wave microwave sources with different frequencies for generating microwaves of different wavelengths for subsequent measurement, wherein N is a natural number greater than 1; and a power combiner connected to the microwave assembly via a high-frequency cable for combining the multiple single-frequency continuous wave microwaves with different frequencies generated by the microwave source assembly, so that subsequent microwave transmission and processing are performed on the same transmission line or device. The power divider, connected to the power combiner via a high-frequency cable, distributes the power of the multi-frequency microwave synthesized by the power combiner and outputs two paths. One output is used for subsequent antenna transmission, and the other serves as the local oscillator signal input to the mixer. The circulator, also connected to the power divider via a high-frequency cable, provides unidirectional transmission. The circulator has a first port, a second port, and a third port. The first port receives the microwave output from one path of the power divider and outputs it to the antenna via the second port. Simultaneously, it transmits the microwave signal received by the antenna from the target object and returned via the second port to the mixer via the third port. The system consists of a transceiver and a circulator. The circulator utilizes its unidirectional transmission characteristic, combined with a back-end antenna, to achieve microwave transmission and reception using a single antenna, thus integrating the transceiver and receiver antennas. The antenna, connected to the circulator via a high-frequency cable, is used to directionally transmit microwaves towards the target under test and simultaneously receive the microwave signal returned from the target. The mixer, connected to the circulator and power divider via high-frequency cables, has a local oscillator port and a signal input port. The mixer receives the microwave signal output from the power divider via its local oscillator port, and simultaneously receives the microwave signal returned from the target via the antenna, output from the circulator, via its signal input port. The microwave signal is mixed to obtain the Doppler frequency shift signal. Multiple wavelengths of microwaves are used, sharing a single transmission, conversion, processing, and receiving antenna. In the early stage of shock wave generation, the wave velocity is high, and the wave array surface reflects both low-frequency long-wave microwaves and high-frequency short-wave microwaves well. However, the interference fringe signal obtained by the short wave has a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wave array surface reflects short waves weakly, making it difficult to obtain the signal. However, the reflection of long waves is still good. At this time, the interference fringe signal is obtained through the long wave, thus enabling the shock wave velocity to be measured at a relatively long distance.

[0009] According to an embodiment of the present invention, in a measurement system for measuring the velocity of a gas shock wave, the antenna can be an ultra-wideband high-gain transceiver antenna, wherein the ultra-wideband operating bandwidth is above 10 GHz and the gain is above 20 dB.

[0010] According to an embodiment of the present invention, the measurement system for measuring the velocity of a gas shock wave may further include: a low-frequency amplifier connected to a mixer for receiving the low-frequency signal output by the mixer and amplifying the signal, wherein the frequency difference of the single-frequency continuous wave microwave source is above 1 GHz, and the highest response frequency domain of the low-frequency amplifier is below 20 MHz, so as to effectively avoid high-frequency interference.

[0011] According to an embodiment of the present invention, the measurement system for measuring the velocity of a gas shock wave may further include: an oscilloscope connected to a low-frequency amplifier for receiving the output signal of the low-frequency amplifier and for data acquisition and storage.

[0012] According to an embodiment of the present invention, the measurement system for measuring the velocity of a gas shock wave may further include: a computer connected to an oscilloscope, for receiving measurement data files stored on the oscilloscope, running data processing software to process the data, and obtaining velocity curve data.

[0013] This invention utilizes ultra-wideband microwave devices such as power combiners, power dividers, circulators, and mixers to broaden the system's operating wavelength range, allowing the shortest and longest wavelengths to differ by several times, thus adapting to shock wave fronts with varying reflectivities. The target under test can also be other targets besides gas shock waves.

[0014] According to another aspect of the present invention, a measurement method for measuring the velocity of a gas shock wave is provided. The measurement method is based on the above-described measurement system for measuring the velocity of a gas shock wave, and includes the following steps: S1, N microwaves of different frequencies are generated by a microwave source component and transmitted to a power combiner via a high-frequency cable transmission line; S2, the power combiner combines the received microwaves, and the combined multi-wavelength microwaves are transmitted to a power divider via a high-frequency cable transmission line; S3, the power divider distributes the power of the received microwaves into two paths, one path is directly transmitted to the local oscillator port of the mixer, and the other path is transmitted to the first port of the circulator; S4, after receiving the microwaves, the first port of the circulator performs unidirectional transmission, and the microwaves are transmitted through the circulator... After the second port outputs the signal, it is transmitted to the antenna via a high-frequency cable. S5. After receiving the microwave, the multiple wavelengths of microwave emitted by the antenna are transmitted through space to the surface of the target under test. The microwave reflected by the moving target is then received by the antenna and transmitted to the second port of the circulator via a high-frequency cable. S6. The second port of the circulator receives the microwave signal returned by the antenna. This signal is transmitted unidirectionally within the circulator and output from the third port of the circulator via a high-frequency cable to the signal input port of the mixer. S7. After receiving the signal, the mixer performs frequency mixing processing on the microwave received from the power divider and the circulator to obtain a Doppler frequency shift signal. This signal is transmitted to the low-frequency amplifier via a high-frequency cable.

[0015] According to an embodiment of the present invention, the measurement method for measuring the velocity of a gas shock wave may further include the following steps: S8, a low-frequency amplifier amplifies the received low-frequency signal, and the amplified signal is transmitted to an oscilloscope.

[0016] According to an embodiment of the present invention, the measurement method for measuring the velocity of a gas shock wave may further include the following steps: S9, the oscilloscope acquires and stores the received signal, and transmits the data file stored in the oscilloscope to a computer.

[0017] According to an embodiment of the present invention, the measurement method for measuring the velocity of a gas shock wave may further include the step of: S10, running data processing software on a computer to perform data processing and obtain a curve / data showing the velocity of the target under test changing over time.

[0018] According to an embodiment of the present invention, in the measurement method for measuring the velocity of a gas shock wave, the computer can perform data processing through the following methods:

[0019] The formula for velocity measurement using the Doppler effect of electromagnetic waves is:

[0020]

[0021] In the formula, u(t) is the velocity of the target being measured, which varies with time; f d (t) represents the Doppler frequency shift value, which varies with time; λ0 is the wavelength of the microwave.

[0022] As can be seen from equation (1), to obtain the velocity value, the Doppler frequency shift value must first be obtained through data processing based on the interference signal recorded in the test. For the system designed in this invention, since multiple wavelengths (multiple λ0) are used, there are also multiple Doppler frequency shift values. Therefore, the signal recorded by the oscilloscope is a signal synthesized from multiple signals with different frequency values. Thus, the traditional method of obtaining the frequency value by measuring the signal period is not applicable, and time-frequency analysis processing of the signal is required.

[0023] The specific data processing steps are as follows:

[0024] Time-frequency analysis processing of signal data is performed, using one or more of the following methods: short-time Fourier transform, wavelet transform, and Hilbert-Huang transform, to obtain the time-frequency spectrum of the Doppler frequency shift value for each wavelength;

[0025] Extract the time-frequency curve data for each wavelength separately;

[0026] The velocity curve data measured at each wavelength are obtained by formula (1);

[0027] By stitching together the velocity curve data measured at each wavelength, a complete shock wave velocity curve data is obtained.

[0028] Based on the above principles, design and data processing, complete shock wave velocity curve data can be obtained. Since continuous wave measurement is used, the measured shock wave velocity changes continuously with time, rather than the average value of a distance in traditional methods.

[0029] Compared with the prior art, the technical solution provided by the embodiments of the present invention can achieve at least the following beneficial effects:

[0030] This invention discloses a measurement system and method for measuring the velocity of gas shock waves. It proposes a system and method for measuring gas shock wave velocity based on a microwave time-domain interferometric velocimetry system established in the centimeter-wave to millimeter-wave frequency band. This system employs multiple wavelengths sharing transmission, transmission, reception, mixing, and amplification links to achieve continuous measurement of the velocity of air shock waves generated by an explosion. The main advantages include: 1) Continuous measurement of shock wave velocity is possible due to the use of continuous wave measurement; 2) The use of multiple wavelengths allows for measurement of shock waves with different velocities, and provides high time resolution at high speeds; 3) The use of a high-gain antenna enables long-distance testing.

[0031] Because the higher the velocity of the air shock wave front generated by an explosion, the higher the density of its interface, and microwaves of different wavelengths have different reflectivities at interfaces with different densities, the measurement system of this invention for measuring the velocity of gas shock waves has multiple wavelengths. In the initial stage of shock wave generation, the wave velocity is high, and the wavefront reflects both long-wave and short-wave microwaves well. However, the interference fringe signal acquired by short waves has a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wavefront reflects short waves weakly, but still reflects long waves well. At this time, the interference fringe signal is acquired by long waves, thus enabling the measurement of the shock wave velocity at a greater distance. Through data processing, the velocity change curve of the shock wave throughout its entire propagation from generation to a greater distance can be obtained.

[0032] The present invention relates to a measurement system and method for measuring the velocity of gas shock waves. Utilizing the Doppler effect of electromagnetic waves, it employs multi-wavelength continuous-wave microwave interferometry. Compared with traditional shock wave velocity testing methods, it can achieve continuous, high-time-resolution, and long-distance measurement of gas shock wave velocity.

[0033] The present invention provides a measurement system and method for measuring the velocity of gas shock waves, which can obtain complete shock wave velocity curve data. Because it uses continuous wave measurement, the measured shock wave velocity changes continuously over time, rather than being an average value over a distance as in traditional methods. By employing multiple wavelengths, and using long-wave signals, the drawback of weak reflection of short-wave waves by low-velocity shock waves, which would otherwise prevent the acquisition of reflected signals, is effectively avoided. Using short-wave signals, high time resolution is achieved when measuring high-speed shock waves. The use of a high-gain transceiver antenna not only avoids measurement errors caused by the angle of separate transceiver antennas but also enables long-distance testing.

[0034] The present invention relates to a measurement system and method for measuring the velocity of gas shock waves. This system utilizes multiple wavelengths of microwaves, sharing a single transmission, conversion, processing, and receiving antenna. Based on the Doppler effect, electromagnetic waves reflect off the surface of a moving target, creating a Doppler frequency shift, from which the target's velocity can be obtained. Given that the higher the velocity of the air shock wave front, the higher the density of its interface, and that microwaves of different wavelengths have different reflectivities at interfaces of different densities, in the initial stage of shock wave generation, the wave velocity is high, and the wavefront surface reflects both low-frequency long-wave microwaves and high-frequency short-wave microwaves well. However, the interference fringe signal acquired by short waves has a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wavefront surface reflects short waves weakly, making it difficult to acquire signals. However, it still reflects long waves well. At this point, interference fringe signals are acquired through long waves, thus enabling the measurement of shock wave velocity at a greater distance.

[0035] This invention relates to a measurement system and method for measuring the velocity of gas shock waves. By employing multiple microwave sources of various frequencies and sharing broadband transmission, power distribution, transmission, reception, mixing, and amplification links, the system continuously measures the velocity of gas shock waves using microwaves of multiple wavelengths within a single system. Compared to traditional measurement methods, this method enables continuous, high-time-resolution, and long-distance measurement of shock wave velocity. It provides a novel testing technology for gas shock wave measurement, avoiding the shortcomings of traditional methods, and has broad application prospects in research and experiments related to detonation shock wave physics, explosion damage assessment, gas detonation, and shock protection. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0037] Figure 1 This is a schematic diagram illustrating a measurement system for measuring the velocity of a gas shock wave according to an embodiment of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.

[0040] Figure 1 This is a schematic diagram illustrating a measurement system for measuring the velocity of a gas shock wave according to an embodiment of the present invention.

[0041] like Figure 1 As shown, a measurement system for measuring the velocity of a gas shock wave is used, wherein the gas shock wave to be measured is a moving target, and the measurement system includes:

[0042] The microwave source assembly 101 includes N single-frequency continuous wave microwave sources with different frequencies to generate microwaves of different wavelengths for subsequent measurements, where N is a natural number greater than 1.

[0043] The power combiner 102 is connected to the microwave component via a high-frequency cable and is used to combine multiple single-frequency continuous wave microwaves of different frequencies generated by the microwave source component 101 so that subsequent microwave transmission and processing can be carried out on the same transmission line or device.

[0044] The power divider 103 is connected to the power combiner 102 via a high-frequency cable. It distributes the power of the multi-frequency microwave synthesized by the power combiner 102 and outputs two paths. One path is used for transmission by the antenna 105, and the other path is used as the local oscillator signal input to the mixer 107.

[0045] Circulator 104 is connected to power divider 103 via a high-frequency cable and is used for unidirectional transmission. Circulator 104 has a first port, a second port, and a third port. After receiving microwaves from one output of power divider 103 at the first port, it outputs them to antenna 105 via the second port. At the same time, it transmits the microwave signal received by antenna 105 from the target under test 106 back through the second port to mixer 107 via the third port. Circulator 104 utilizes its unidirectional transmission characteristic and, in conjunction with the back-end antenna 105, enables the same antenna 105 to perform microwave transmission and reception, thus integrating the transceiver antenna 105.

[0046] Antenna 105 is connected to circulator 104 via a high-frequency cable and is used to directionally transmit microwaves to target 106 and receive microwave signals returned from target 106.

[0047] Mixer 107 is connected to circulator 104 and power divider 103 via high-frequency cables. Mixer 107 has a local oscillator port and a signal input port. Mixer 107 receives the microwave signal output from another path of power divider 103 through the local oscillator port. At the same time, mixer 107 receives the microwave signal returned from target 106 by antenna 105 and output from circulator 104 through the signal input port, and performs mixing to obtain Doppler frequency shift signal.

[0048] The system employs multiple wavelengths of microwaves, all sharing a single transmission, conversion, processing, and transceiver antenna 105. In the initial stage of shock wave generation, the wave velocity is relatively high, and the wave array surface reflects both low-frequency long-wave microwaves and high-frequency short-wave microwaves well. However, the interference fringe signal acquired by the short-wave is at a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wave array surface reflects short-wave microwaves weakly, making it difficult to acquire the signal. However, it still reflects long-wave microwaves well. At this point, the interference fringe signal is acquired through the long-wave, thus enabling the measurement of the shock wave velocity at a greater distance.

[0049] The present invention relates to a measurement system and method for measuring the velocity of gas shock waves. This system utilizes multiple wavelengths of microwaves, sharing a single transmission, conversion, processing, and receiving antenna. Based on the Doppler effect, electromagnetic waves reflect off the surface of a moving target, creating a Doppler frequency shift, from which the target's velocity can be obtained. Given that the higher the velocity of the air shock wave front, the higher the density of its interface, and that microwaves of different wavelengths have different reflectivities at interfaces of different densities, in the initial stage of shock wave generation, the wave velocity is high, and the wavefront surface reflects both low-frequency long-wave microwaves and high-frequency short-wave microwaves well. However, the interference fringe signal acquired by short waves has a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wavefront surface reflects short waves weakly, making it difficult to acquire signals. However, it still reflects long waves well. At this point, interference fringe signals are acquired through long waves, thus enabling the measurement of shock wave velocity at a greater distance.

[0050] According to one or more embodiments of the present invention, in a measurement system for measuring the velocity of a gas shock wave, the antenna 105 is an ultra-wideband high-gain transceiver antenna, wherein the ultra-wideband operating bandwidth is above 10 GHz and the gain is above 20 dB.

[0051] This invention discloses a measurement system and method for measuring the velocity of gas shock waves. It proposes a system and method for measuring gas shock wave velocity based on a microwave time-domain interferometric velocimetry system established in the centimeter-wave to millimeter-wave frequency band. This system employs multiple wavelengths sharing transmission, transmission, reception, mixing, and amplification links to achieve continuous measurement of the velocity of air shock waves generated by an explosion. The main advantages include: 1) Continuous measurement of shock wave velocity is possible due to the use of continuous wave measurement; 2) The use of multiple wavelengths allows for measurement of shock waves with different velocities, and provides high time resolution at high speeds; 3) The use of a high-gain antenna enables long-distance testing.

[0052] According to one or more embodiments of the present invention, the measurement system for measuring the velocity of a gas shock wave further includes: a low-frequency amplifier 108, connected to a mixer 107, for receiving the low-frequency signal output by the mixer 107 and amplifying the signal.

[0053] Among them, the frequency difference of the single-frequency continuous wave microwave source is above 1 GHz, and the highest response frequency domain of the low-frequency amplifier 108 is below 20 MHz, so as to effectively avoid high-frequency interference.

[0054] According to one or more embodiments of the present invention, the measurement system for measuring the velocity of a gas shock wave further includes: an oscilloscope 109 connected to a low-frequency amplifier 108 for receiving the output signal of the low-frequency amplifier 108 and for data acquisition and storage.

[0055] According to one or more embodiments of the present invention, the measurement system for measuring the velocity of a gas shock wave further includes: a computer 110 connected to an oscilloscope 109, for receiving measurement data files stored on the oscilloscope 109, running data processing software to process the data, and obtaining velocity curve data.

[0056] This invention utilizes ultra-wideband microwave devices such as a power combiner 102, a power divider 103, a circulator 104, and a mixer 107 to broaden the system's operating wavelength range, allowing the shortest and longest wavelengths to differ by several times, thus adapting to shock wave fronts with varying reflectivities. The target 106 can also be any target other than a gas shock wave.

[0057] Because the higher the velocity of the air shock wave front generated by an explosion, the higher the density of its interface, and microwaves of different wavelengths have different reflectivities at interfaces of different densities, the measurement system of this invention for measuring the velocity of gas shock waves has multiple wavelengths. In the initial stage of shock wave generation, the wave velocity is high, and the wavefront reflects both long-wave and short-wave microwaves well. However, the interference fringe signal acquired by short waves has a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wavefront reflects short waves weakly, but still reflects long waves well. At this time, the interference fringe signal is acquired by long waves, thus enabling the measurement of shock wave velocity at a greater distance. Through data processing, the velocity change curve of the shock wave throughout its entire propagation from generation to a greater distance can be obtained.

[0058] According to another aspect of the present invention, a measurement method for measuring the velocity of a gas shock wave is provided. The measurement method is implemented based on the above-described measurement system for measuring the velocity of a gas shock wave, and the measurement method includes the following steps:

[0059] S1. Microwaves of N frequencies generated by microwave source component 101 are transmitted to power combiner 102 via high-frequency cable transmission line;

[0060] S2, the power combiner 102 combines / synthesizes the received microwaves, and the combined multi-wavelength microwaves are transmitted to the power divider 103 via a high-frequency cable transmission line.

[0061] S3. The power divider 103 distributes the power of the received microwave into two paths: one path is directly transmitted to the local oscillator port of the mixer 107, and the other path is transmitted to the first port of the circulator 104.

[0062] S4. After receiving microwaves at the first port of circulator 104, the microwaves are transmitted unidirectionally and output through the second port of circulator 104, and then transmitted to antenna 105 through a high-frequency cable transmission line.

[0063] S5. After receiving microwaves, the multiple wavelengths of microwaves emitted by the antenna 105 are transmitted through space to the surface of the target 106. The microwaves reflected by the moving target are then received by the antenna 105 and transmitted to the second port of the circulator 104 via a high-frequency cable.

[0064] S6. The second port of the circulator 104 receives the microwave signal returned by the antenna 105. The signal is transmitted unidirectionally within the circulator 104 and output from the third port of the circulator 104 to the signal input port of the mixer 107 via a high-frequency cable transmission line.

[0065] S7. After receiving the signal, mixer 107 performs frequency mixing on the microwave received from power divider 103 and circulator to obtain a Doppler frequency shift signal, which is transmitted to low frequency amplifier 108 via high frequency cable transmission line.

[0066] The present invention provides a measurement system and method for measuring the velocity of gas shock waves, which can obtain complete shock wave velocity curve data. Because it uses continuous wave measurement, the measured shock wave velocity changes continuously over time, rather than being an average value over a distance as in traditional methods. By employing multiple wavelengths, and using long-wave signals, the drawback of weak reflection of short-wave waves by low-velocity shock waves, which would otherwise prevent the acquisition of reflected signals, is effectively avoided. Using short-wave signals, high time resolution is achieved when measuring high-speed shock waves. The use of a high-gain transceiver antenna not only avoids measurement errors caused by the angle of separate transceiver antennas but also enables long-distance testing.

[0067] According to one or more embodiments of the present invention, the measurement method for measuring the velocity of a gas shock wave further includes the steps of: S9, the oscilloscope 109 acquires and stores the received signal, and transmits the data file stored in the oscilloscope 109 to the computer 110.

[0068] According to one or more embodiments of the present invention, the measurement method for measuring the velocity of a gas shock wave further includes the step of: S10, the computer 110 runs data processing software to perform data processing and obtain the curve / data of the velocity of the target 106 changing with time.

[0069] According to one or more embodiments of the present invention, in the measurement method for measuring the velocity of a gas shock wave, the computer 110 performs data processing by the following method:

[0070] The formula for velocity measurement using the Doppler effect of electromagnetic waves is:

[0071]

[0072] In the formula, u(t) represents the velocity of the target under test, which varies with time; f d(t) represents the Doppler frequency shift value, which varies with time; λ0 is the wavelength of the microwave.

[0073] As can be seen from equation (1), to obtain the velocity value, the Doppler frequency shift value must first be obtained through data processing based on the interference signal recorded in the test. For the system designed in this invention, since multiple wavelengths (multiple λ0) are used, there are also multiple Doppler frequency shift values. Therefore, the signal recorded by the oscilloscope 109 is a signal synthesized from multiple signals with different frequency values. Thus, the traditional method of obtaining the frequency value by measuring the signal period is not applicable, and time-frequency analysis processing of the signal is required.

[0074] The specific data processing steps are as follows:

[0075] Time-frequency analysis processing of signal data is performed, using one or more of the following methods: short-time Fourier transform, wavelet transform, and Hilbert-Huang transform, to obtain the time-frequency spectrum of the Doppler frequency shift value for each wavelength;

[0076] Extract the time-frequency curve data for each wavelength separately;

[0077] The velocity curve data measured at each wavelength are obtained by formula (1);

[0078] By stitching together the velocity curve data measured at each wavelength, a complete shock wave velocity curve data is obtained.

[0079] Based on the above principles, design and data processing, complete shock wave velocity curve data can be obtained. Since continuous wave measurement is used, the measured shock wave velocity changes continuously with time, rather than the average value of a distance in traditional methods.

[0080] The present invention relates to a measurement system and method for measuring the velocity of gas shock waves. Utilizing the Doppler effect of electromagnetic waves, it employs multi-wavelength continuous-wave microwave interferometry. Compared with traditional shock wave velocity testing methods, it can achieve continuous, high-time-resolution, and long-distance measurement of gas shock wave velocity.

[0081] The working principle of this invention is as follows: According to the Doppler effect, electromagnetic waves reflect off the surface of a moving target, creating a Doppler frequency shift. The velocity of the target can be obtained from the frequency shift value. Based on the characteristic that the higher the velocity of the air shock wave front, the higher the density of its interface, and that microwaves of different wavelengths have different reflectivities at interfaces of different densities, this invention uses microwaves of multiple wavelengths, sharing a single set of transmission, conversion, processing, and transceiver antenna units. In the initial stage of shock wave generation, the wave velocity is high, and the wavefront surface reflects both low-frequency long-wave microwaves and high-frequency short-wave microwaves well. However, the interference fringe signal obtained from short waves has a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wavefront surface reflects short waves weakly, making it difficult to obtain signals. However, it still reflects long waves well. At this point, the interference fringe signal is obtained through long waves, thus enabling the measurement of the shock wave velocity at a greater distance.

[0082] This invention relates to a measurement system and method for measuring the velocity of gas shock waves. By employing multiple microwave sources of various frequencies and sharing broadband transmission, power distribution, transmission, reception, mixing, and amplification links, the system continuously measures the velocity of gas shock waves using microwaves of multiple wavelengths within a single system. Compared to traditional measurement methods, this method enables continuous, high-time-resolution, and long-distance measurement of shock wave velocity. It provides a novel testing technology for gas shock wave measurement, avoiding the shortcomings of traditional methods, and has broad application prospects in research and experiments related to detonation shock wave physics, explosion damage assessment, gas detonation, and shock protection.

[0083] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.

Claims

1. A measurement system for measuring the velocity of a gas shock wave, wherein, The gas shock wave to be measured is a moving target, and the measurement system includes: A microwave source assembly comprises N single-frequency continuous wave microwave sources with different frequencies to generate microwaves of different wavelengths for subsequent measurements, where N is a natural number greater than 1. A power combiner is connected to the microwave component via a high-frequency cable and is used to combine multiple single-frequency continuous wave microwaves of different frequencies generated by the microwave source component so that subsequent microwave transmission and processing can be carried out on the same transmission line or device. The power divider is connected to the power combiner via a high-frequency cable. It distributes the power of the multi-frequency microwave synthesized by the power combiner and outputs two paths. One path is used for subsequent antenna transmission, and the other path is used as the local oscillator signal input to the mixer. A circulator, connected to the power divider via a high-frequency cable, serves as a unidirectional transmission device. The circulator has a first port, a second port, and a third port. The first port receives microwave signals from one output path of the power divider and outputs them to the antenna via the second port. Simultaneously, the antenna receives microwave signals returning from the target under test via the second port and transmits them to the mixer via the third port. Utilizing its unidirectional transmission characteristic, the circulator, combined with the rear-end antenna, enables a single antenna to perform microwave transmission and reception, achieving integrated transceiver antenna functionality. The antenna, connected to the circulator via a high-frequency cable, is used to directionally transmit microwaves to the target under test and simultaneously receive microwave signals returned from the target under test. A mixer is connected to the circulator and the power divider via a high-frequency cable. The mixer has a local oscillator port and a signal input port. The mixer receives the microwave signal output from another path of the power divider through the local oscillator port. At the same time, the mixer receives the microwave signal returned from the target under test by the antenna and output from the circulator through the signal input port. The mixer performs mixing to obtain a Doppler frequency shift signal. This method employs multiple wavelengths of microwaves, all sharing a single transmission, conversion, processing, and transceiver antenna. In the initial stage of shock wave generation, the wave velocity is relatively high, and the wave array surface reflects both low-frequency long-wave microwaves and high-frequency short-wave microwaves well. However, the interference fringe signal acquired by the short-wave is at a higher frequency, thus providing higher time resolution. As the propagation distance of the shock wave increases, the wave velocity decreases, and the wave array surface reflects short-waves less effectively, making it difficult to acquire the signal. However, it still reflects long-waves well. At this point, the interference fringe signal is acquired through the long-wave, thus enabling the measurement of the shock wave velocity at a greater distance.

2. The measurement system for measuring gas shock wave velocity as described in claim 1, wherein, The antenna is an ultra-wideband high-gain transceiver antenna, wherein the ultra-wideband operating bandwidth is above 10 GHz and the gain is above 20 dB.

3. The measurement system for measuring gas shock wave velocity as described in claim 1, further comprising: A low-frequency amplifier, connected to the mixer, is used to receive the low-frequency signal output from the mixer and amplify it. Among them, the frequency difference of the single-frequency continuous wave microwave source is above 1 GHz, and the highest response frequency domain of the low-frequency amplifier is below 20 MHz, so as to effectively avoid high-frequency interference.

4. The measuring system for measuring gas shock wave velocity as described in claim 3, further comprising: An oscilloscope, connected to the low-frequency amplifier, is used to receive the output signal of the low-frequency amplifier and perform data acquisition and storage.

5. The measuring system for measuring gas shock wave velocity as described in claim 4, further comprising: A computer, connected to the oscilloscope, is used to receive the measurement data file stored on the oscilloscope, run data processing software to process the data, and obtain speed curve data.

6. A method for measuring the velocity of a gas shock wave, said method being implemented based on the measurement system for measuring the velocity of a gas shock wave according to any one of claims 1-5, said measurement method comprising the following steps: S1. Microwaves of N frequencies generated by the microwave source component are transmitted to the power combiner via a high-frequency cable transmission line; S2. The power combiner combines the received microwaves, and the combined multi-wavelength microwaves are transmitted to the power divider via a high-frequency cable transmission line. S3. The power divider distributes the power of the received microwaves into two paths: one path is directly transmitted to the local oscillator port of the mixer, and the other path is transmitted to the first port of the circulator. S4. After receiving microwaves at the first port of the circulator, the microwaves are transmitted unidirectionally and output through the second port of the circulator, and then transmitted to the antenna via a high-frequency cable. S5. After receiving microwaves, the multiple wavelengths of microwaves emitted by the antenna are transmitted through space to the surface of the target to be measured. The microwaves reflected by the moving target are then received by the antenna and transmitted to the second port of the circulator via a high-frequency cable. S6. The second port of the circulator receives the microwave signal returned by the antenna. This signal is transmitted unidirectionally within the circulator and output from the third port of the circulator to the signal input port of the mixer via a high-frequency cable transmission line. S7. After receiving the signal, the mixer performs frequency mixing on the microwave received from the power divider and circulator to obtain a Doppler frequency shift signal, which is transmitted to the low-frequency amplifier via a high-frequency cable transmission line.

7. The measurement method for measuring the velocity of a gas shock wave as described in claim 6 further includes the step of: S8, a low-frequency amplifier amplifies the received low-frequency signal, and the amplified signal is transmitted to an oscilloscope.

8. The measurement method for measuring the velocity of a gas shock wave as described in claim 7 further includes the step: S9, the oscilloscope acquires and stores the received signal, and transmits the data file stored in the oscilloscope to the computer.

9. The measurement method for measuring the velocity of a gas shock wave as described in claim 8 further includes the step: S10, running data processing software on a computer to process the data and obtain the curve / data of the velocity of the target under test changing with time.

10. The measurement method for measuring gas shock wave velocity as described in claim 9, wherein, Computers process data using the following methods: The formula for velocity measurement using the Doppler effect of electromagnetic waves is: In the formula, u(t) is the velocity of the target being measured, which varies with time; f d (t) represents the Doppler frequency shift value, which varies with time; λ0 is the wavelength of the microwave. As can be seen from equation (1), to obtain the velocity value, the Doppler frequency shift value must first be obtained through data processing based on the interference signal recorded in the test. For the system designed in this invention, since multiple wavelengths (multiple λ0) are used, there are also multiple Doppler frequency shift values. Therefore, the signal recorded by the oscilloscope is a signal synthesized from multiple signals with different frequency values. Thus, the traditional method of obtaining the frequency value by measuring the signal period is not applicable, and time-frequency analysis processing of the signal is required. The specific data processing steps are as follows: Time-frequency analysis processing of signal data is performed, using one or more of the following methods: short-time Fourier transform, wavelet transform, and Hilbert-Huang transform, to obtain the time-frequency spectrum of the Doppler frequency shift value for each wavelength; Extract the time-frequency curve data for each wavelength separately; The velocity curve data measured at each wavelength are obtained by formula (1); By stitching together the velocity curve data measured at each wavelength, a complete shock wave velocity curve data is obtained. Based on the above principles, design and data processing, complete shock wave velocity curve data can be obtained.

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