System and method for measuring ballistic trajectory in light-gas gun and artillery

Abstract

The invention relates to a system and a method for measuring ballistic trajectories in a light-gas gun and an artillery, and the system comprises a first microwave source assembly, a first power amplifier, a first circulator, a horn antenna, a second microwave source assembly, a second power amplifier, a second circulator, a linear polarization antenna and a microwave reflection and transmission plate, the directions of microwaves emitted by the horn antenna and the linearly polarized antenna form an angle of 90 degrees, the microwave reflection and transmission plate is arranged on an angular bisector of the angle formed by the horn antenna and the linearly polarized antenna, and the microwave reflection and transmission plate enables short-wavelength microwaves emitted by the horn antenna to be directly transmitted to a target to be measured. And long-wavelength microwaves emitted by the linear polarization antenna can be reflected to a to-be-measured target according to an angle of 45 degrees. According to the system for measuring the ballistic trajectory in the light-gas gun and the artillery, long-wave microwaves are reflected on the front surface of forward gas, short waves are reflected on the surface of a projectile, and therefore long-distance, continuous and simultaneous measurement of the speed of the forward gas and the speed of the projectile is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of light gas gun and artillery interior ballistics measurement, and in particular to a system and method for light gas gun and artillery interior ballistics measurement. Background Art

[0002] Measuring the velocity history of light gas gun / artillery projectiles in their interior ballistic trajectory is crucial for their design, interior ballistic calculations, loading parameter optimization, and diagnostic analysis of trajectory anomalies. Because light gas gun / artillery projectiles are not completely sealed to the launch tube wall, a large amount of high-speed forward gas (several kilometers per second) is typically present in front of the projectile during its acceleration within the launch tube, significantly affecting the measured interior ballistic velocity. Furthermore, determining the velocity of this forward gas is crucial for studying the state of high-velocity ionized gas.

[0003] Traditional methods for measuring the interior ballistic velocity of light gas guns / cannons, such as beam interruption and magnetic induction, measure the time it takes a projectile to travel a certain distance at the muzzle. Dividing the distance by the travel time yields the average velocity for that distance. These methods primarily utilize beam interruption and magnetic induction. The beam interruption method uses two laser beams spaced a certain distance apart at the muzzle. When the projectile reaches the beam position, the beams are interrupted, generating a signal. An oscilloscope records the instants of interruption of the two beams, yielding the time difference. The distance between the two beams is then divided by the time difference to yield the average velocity for the projectile over that distance. The magnetic induction method operates on a similar principle, except that the sensor used to detect the projectile's arrival uses a toroidal coil with a magnetic core. Both beam interruption and magnetic induction methods only measure the average velocity of the projectile at the muzzle, failing to capture the velocity profile of the projectile throughout its entire interior ballistic trajectory. These methods are also susceptible to the influence of the forward gas flow. Furthermore, since they measure average velocity, the velocity measurement can be subject to significant error for hypervelocity or when the projectile experiences significant acceleration before exiting the muzzle.

[0004] Various laser interferometry methods utilize the Doppler effect of lasers and calculate the projectile velocity by measuring the Doppler frequency shift. References such as Peng Qixian, Meng Jianhua, Liu Jun, et al. Application of laser interferometry in the study of artillery interior ballistics [J]. Journal of Ballistics, 2008, 20(3): 96-99. Tao Tianjiong, Wang Xiang, Chen Hong, et al. Application of frequency aliasing in velocity measurement of gas gun interior ballistics [J]. Journal of High Pressure Physics, 2013, 27(4): 523-527. DOI:10.11858 / gywlxb.2013.04.009.) use laser interferometry, which mainly utilizes the Doppler effect. Laser is emitted to the surface of the projectile to be measured, and the laser reflected from the projectile surface is collected. The laser then interferes with the reference light, and the interference signal is output by the photodetector. The projectile velocity is obtained by calculating the frequency of the interference signal. However, there are problems with the laser interferometry method: it is difficult to obtain a complete interior ballistic velocity curve due to the influence of the forward gas; the test signal is poor due to the influence of the surface roughness and shape of the projectile, and it is even difficult to obtain an effective signal; the bandwidth of the signal acquisition and recording system is high. For a high-speed projectile of 8km / s, the bandwidth must be above 10GHz, which is expensive; the collimation optical path is complex, and the expensive long depth of field lens will be damaged during the measurement.

[0005] The general microwave interferometry method also uses the Doppler effect of electromagnetic waves to calculate the projectile velocity value by measuring the Doppler frequency shift value of a single wavelength microwave. Literature (Jia Xing, Tang Longhuang, Weng Jidong, et al. Diagnosis of ballistic parameters of two-stage light gas gun / gun based on microwave interferometry technology [J]. Explosion and Shockwave. 2022, 42(3). Peng Juntao. Design and implementation of radar terminal for measuring projectile motion parameters inside and outside the bore based on microwave interferometry principle [D]. Nanjing University of Science and Technology, 2016. Liu Bin, Xiao Jian, Guo Yalong, et al. Research on measurement method of projectile parameters inside the bore of large-caliber artillery [J]. Journal of Projectiles, Rockets and Guidance, 2010, 30(1):167-169.) etc. adopt single-wavelength continuous wave microwave velocity measurement method, which mainly utilizes the Doppler effect. By emitting microwaves to the surface of the projectile to be measured, the microwaves reflected from the projectile surface are collected and then interfered with the reference signal. The interference signal is output by the mixer, and the projectile motion speed is obtained by calculating the frequency of the interference signal. However, the single-wavelength continuous-wave microwave velocimetry method has low time resolution at low speeds. Moreover, when the amount of the forehand gas is large and the speed is high, due to the different transmittances of the forehand gas to different wavelengths, the single-wavelength microwave velocimetry method can only measure the speed of one of the targets, the projectile or the forehand gas, at each moment.

[0006] The above existing measurement methods cannot achieve long-distance, continuous, high-time-resolution, and multi-target measurements. Therefore, it is urgent to develop a system or method for light gas gun and artillery interior ballistic measurement that can achieve long-distance, continuous, high-time-resolution, and multi-target measurements. Summary of the Invention

[0007] The technical problem to be solved by the present invention is that the existing measurement method cannot achieve long-distance, continuous, high time resolution and multi-target measurement when measuring the interior ballistics of light gas guns and artillery.

[0008] To solve the above technical problems, according to one aspect of the present invention, a system for measuring the interior ballistics of light gas guns and artillery is provided, wherein the target to be measured includes the high-speed moving forward gas to be measured and the projectile to be measured in the interior ballistics of the light gas gun or artillery, and the system includes: a first microwave source component for generating single-frequency continuous microwaves, which are short-wave microwaves, for subsequent measurement; a first power amplifier connected to the first microwave source component, receiving the microwaves generated by the first microwave source component for power amplification, and outputting a relatively high-power microwave for emission to the target to be measured, so that a relatively strong signal can be reflected back from the target to be measured; a first circulator for unidirectional microwave transmission, having a first port, a second port, and a third port , wherein the first port of the first circulator receives the microwave output by the first power amplifier and outputs it through the second port; the horn antenna receives the microwave output by the second port of the first circulator, and transmits microwaves to the pre-charge gas to be measured and the projectile to be measured, and at the same time receives the microwave signals reflected from the pre-charge gas to be measured and the projectile to be measured, and returns them to the second port of the first circulator; the first circulator outputs the microwave signals returned from the target to be measured received by the horn antenna through the third port, and utilizes the unidirectional transmission characteristics of the circulator, combined with the rear-end horn antenna, to realize microwave transmission and reception with the same antenna, realizing antenna transmission and reception integration; the second microwave source component is used to generate single-frequency continuous microwaves, which are long-wave microwaves, for the rear The second power amplifier is connected to the second microwave source component, receives the microwaves generated by the second microwave source component for power amplification, and outputs microwaves with higher power for emission to the target to be measured, so that a stronger signal can be reflected back from the target to be measured; the second circulator is used for unidirectional transmission of microwaves, and has a first port, a second port and a third port, wherein the first port of the second circulator receives the microwaves output by the second power amplifier and outputs them through the second port; the linearly polarized antenna receives the microwaves output by the second port of the second circulator, and directionally emits microwaves to the pre-charge gas to be measured and the projectile to be measured, and at the same time receives the microwave signals reflected from the pre-charge gas to be measured and the projectile to be measured, and returns them to the second circulator The second circulator outputs the microwave signal received from the horn antenna and returned from the target to be measured through the third port. By utilizing the unidirectional transmission characteristic of the circulator and combining it with the rear-end linearly polarized antenna, the same antenna realizes microwave transmission and reception, thereby realizing an integrated antenna transmission and reception. The microwave reflection and transmission plate is a metal mesh structure, which is used to allow the short-wavelength microwaves emitted by the horn antenna to directly transmit through and reach the target to be measured; and is used to allow the long-wavelength microwaves emitted by the linearly polarized antenna to be reflected at a 45° angle and reach the target to be measured, wherein the directions of the microwaves emitted by the horn antenna and the linearly polarized antenna form an angle of 90°, and wherein the microwave reflection and transmission plate is arranged on the bisector of the angle formed by the horn antenna and the linearly polarized antenna.

[0009] According to an embodiment of the present invention, the system for measuring interior ballistics of light gas guns and artillery cannons may further include:

[0010] The first reference microwave source is configured to generate microwaves, wherein the difference between the frequency of the microwaves outputted by the first microwave source component and the microwave frequency of the first microwave source component is no more than 10 MHz. The generated microwaves are used to output local oscillator signals for a subsequent first mixer. The first mixer comprises a first circulator, which transmits a microwave signal received from a horn antenna and returned from a target to be measured to the first mixer via the third port of the first circulator. The first mixer receives the local oscillator signal inputted by the first reference microwave source and the microwave signal outputted from the third port of the first circulator, performs mixing, and obtains a signal containing a Doppler frequency shift signal. The second reference microwave source is configured to generate microwaves, wherein the difference between the frequency of the microwaves outputted by the second microwave source component and the microwave frequency of the second microwave source component is no more than 10 MHz. The generated microwaves are used to output local oscillator signals for a subsequent second mixer. The second mixer comprises a second circulator, which transmits a microwave signal received from a linearly polarized antenna and returned from a target to be measured to the second mixer via the third port of the second circulator. The second mixer receives the local oscillator signal inputted by the second reference microwave source and the microwave signal outputted from the third port of the second circulator, performs mixing, and obtains a signal containing a Doppler frequency shift signal.

[0011] According to an embodiment of the present invention, the system for measuring interior ballistics of light gas guns and artillery cannons may further include: a low-frequency signal amplifier for respectively receiving the low-frequency signals containing Doppler frequency shift signals output by the first mixer and the second mixer, and performing signal amplification respectively.

[0012] According to an embodiment of the present invention, the system for measuring interior ballistics of light gas guns and artillery cannons may further include: an oscilloscope for receiving the output signal of the low-frequency signal amplifier and performing data acquisition and storage.

[0013] According to an embodiment of the present invention, a system for measuring interior ballistics of light gas guns and artillery cannons, wherein the frequency of the single-frequency continuous microwaves generated by the first microwave source assembly can be above 20 GHz; the frequency of the single-frequency continuous microwaves generated by the second microwave source assembly can be below 10 GHz, wherein the wavelength of the single-frequency continuous microwaves generated by the second microwave source assembly is longer than the wavelength of the single-frequency continuous microwaves generated by the first microwave source assembly.

[0014] According to another aspect of the present invention, a method for measuring the interior ballistics of light gas guns and artillery is provided. The method is implemented based on the above system for measuring the interior ballistics of light gas guns and artillery, wherein the method comprises the following steps: S1, a first microwave source assembly generates a single-frequency continuous microwave, which is transmitted to a first power amplifier via a transmission line including a high-frequency cable; a second microwave source assembly generates a single-frequency continuous microwave, which is transmitted to a second power amplifier via a transmission line including a high-frequency cable; S2, the first power amplifier amplifies the power of the received microwave, and the amplified microwave is transmitted to the first port of a first circulator via the transmission line; the second power amplifier amplifies the power of the received microwave, and the amplified microwave is transmitted to the first port of a second circulator via the transmission line; S3, after receiving the microwave at the first port of the first circulator, the microwave is unidirectionally transmitted, outputted via the second port of the first circulator, and then transmitted to a horn antenna via the transmission line; after receiving the microwave at the first port of the second circulator, the microwave is unidirectionally transmitted, outputted via the second port of the second circulator, and then transmitted to a linearly polarized antenna via the transmission line; S4, the horn antenna receives the microwave After receiving the microwaves, the microwaves are emitted into space. After being transmitted through space, they are transmitted from the microwave reflection and transmission plate and reach the surface of the moving target to be measured. The microwaves reflected by the target to be measured are transmitted through space and then received by the horn antenna. After receiving the microwaves, the linearly polarized antenna emits the microwaves into space. After being transmitted through space, they are reflected from the microwave reflection and transmission plate and reach the surface of the moving target to be measured. The microwaves reflected by the target to be measured are transmitted through space and then received by the linearly polarized antenna. S5. After the horn antenna receives the microwaves from space, they are transmitted to the second port of the first circulator via a transmission line. After the linearly polarized antenna receives the microwaves from space, they are transmitted to the second port of the second circulator via a transmission line. S6. The second port of the first circulator receives the microwave signal returned from the antenna. The signal is transmitted unidirectionally within the circulator and output from the third port of the first circulator via a transmission line to the signal input port of the first mixer. The second port of the second circulator receives the microwave signal returned from the antenna. The signal is transmitted unidirectionally within the circulator and output from the third port of the second circulator via a transmission line to the signal input port of the second mixer.

[0015] According to an embodiment of the present invention, the method for measuring the interior ballistics of light gas guns and artillery may further include the following steps: S7, after the first mixer receives a signal from the first circulator, it mixes it with the microwave received from the first reference microwave source to obtain a signal containing a Doppler frequency shift signal, and the signal is transmitted to the low-frequency signal amplifier via a transmission line; after the second mixer receives a signal from the second circulator, it mixes it with the microwave received from the second reference microwave source to obtain a signal containing a Doppler frequency shift signal, and the signal is transmitted to the low-frequency signal amplifier via a transmission line.

[0016] According to an embodiment of the present invention, the method for measuring interior ballistics of light gas guns and artillery cannons may further include the step: S8, the low-frequency signal amplifier amplifies the received low-frequency signals respectively, and transmits the amplified signals to the oscilloscope.

[0017] According to an embodiment of the present invention, the method for measuring interior ballistics of light gas guns and artillery cannons may further include the step of: S9, the oscilloscope collects and stores the received signals.

[0018] According to an embodiment of the present invention, the method for measuring interior ballistics of a light gas gun and a cannon may further include the step of: S10, performing data processing by a computer to obtain a curve / data of the velocity change of the target to be measured over time, wherein the data processing by the computer includes the following calculation method:

[0019] Assume that the frequency of microwave output by the microwave source component is , the frequency of the microwave carrying Doppler shift information output from the third port of the circulator is , where the target moves towards the antenna and takes a + sign, and moves away from the antenna and takes a - sign; let the frequency of the microwave output by the reference microwave source be , is the up-conversion value, that is, the frequency value to which the Doppler signal needs to be "moved" , the signal frequency output after the mixer , we can get the "apparent" speed Formula (1); the actual speed of the target is , The frequency is The microwave wavelength corresponding to the microwave source component;

[0020] (1)

[0021] , corresponds to the "apparent" speed of the target when it is stationary, where , and the target moves toward the antenna, the actual speed of the target can be calculated using formula (2):

[0022] (2)

[0023] The data processing using the time-frequency analysis method includes the following steps: S11, calculating the "apparent" speed of the target when it is stationary ; S12, perform time-frequency analysis on the signal data to obtain a time-frequency spectrum; S13, extract the time-frequency curve data and calculate the "apparent" speed by formula (1) ; S14, calculate the speed data of the target to be measured by formula (2);

[0024] The data processing using the orthogonal signal I / Q demodulation method includes the following steps: S21, calculating the "apparent" speed of the target when it is stationary ; S22, calculate the phase of the signal; S23, differentiate the phase and calculate the "apparent" speed ; S24, calculate the speed data of the target to be measured by formula (2);

[0025] Among them, since long-wave and short-wave dual-wavelength continuous wave measurement is used, complete velocity curve data of the forward gas and projectile can be obtained respectively, and are not affected by the forward gas; since the wavelength of microwaves is longer, it is less affected by the surface roughness and shape of the projectile, and the bandwidth requirement for the signal acquisition and recording system is low, less than 20MHz; since heterodyne up-conversion is used, in time-frequency analysis, the window time is shorter for the same number of signal stripes, thus having higher time resolution; since a high-gain antenna is used, and for microwaves, the launch tube of an artillery or light gas gun is equivalent to a waveguide, it is possible to measure targets inside a long-tube launch tube.

[0026] Compared with the prior art, the technical solution provided by the embodiments of the present invention can achieve at least the following beneficial effects:

[0027] Given the varying transmittances of high-speed fore-flow gas to microwaves of different wavelengths, the present system and method for measuring interior ballistics of light-gas guns and artillery proposes a dual-wavelength, heterodyne up-conversion, and shared-transmission microwave interferometry system. A reflective-transmissive plate, designed to reflect long wavelengths and transmit short wavelengths, is designed and utilized for dual-wavelength measurement. Taking advantage of the varying reflectivity and transmittances of high-speed ionized fore-flow gas to microwaves of different wavelengths, one wavelength is used to measure the projectile velocity through the fore-flow gas, while the other wavelength is used to measure the velocity of the high-speed fore-flow gas. The heterodyne up-conversion design increases the number of interference fringes per unit time, thereby improving temporal resolution. Key features include: 1) simultaneous and continuous measurement of the projectile and fore-flow gas velocities within the launch tube; 2) high temporal resolution; 3) capability for measuring targets within long launch tubes; 4) minimal impact from projectile surface roughness and shape, requiring low bandwidth for the signal acquisition and recording system, simplifying the test layout and maximizing cost-effective consumables; and 5) convenient switching between single- and dual-wavelength modes to meet testing needs.

[0028] The system for measuring the interior ballistics of light gas guns and artillery, according to the present invention, comprises two independent microwave interferometry units, each utilizing different wavelengths, sharing a microwave reflective-transmission plate, a low-frequency signal amplifier, and a data acquisition and recording unit, such as an oscilloscope. Each microwave interferometry unit comprises a microwave source assembly, a power amplifier, a circulator, an antenna, a reference microwave source, and a mixer. Utilizing the Doppler effect, it can measure the velocity of a moving target. A certain frequency difference exists between the microwave source assembly and the reference microwave source in each unit, enabling heterodyne up-conversion of the Doppler-shifted signal in the mixer, enabling high temporal resolution during signal processing. The reflective-transmission plate is designed by utilizing the polarization properties of microwaves and the transmission characteristics of short-wavelength microwaves through metal mesh. The long-wavelength unit uses a linearly polarized antenna to transmit microwaves, which are reflected by the reflective-transmission plate. The short-wavelength unit's antenna emits microwaves with a shorter wavelength, which are transmitted by the reflective-transmission plate. The long-wave and short-wave antennas are angled at 90°, and the reflective-transmissive plate is at a 45° angle to the antennas. This allows microwaves of both wavelengths to travel along the same path to the target. This invention primarily measures the interior ballistics of artillery / light-gas guns. In a dual-wavelength microwave transmission tube, the long-wavelength microwaves are reflected by the front surface of the forward gas, while the short-wavelength microwaves penetrate the forward gas and reflect from the projectile surface, enabling simultaneous measurement of both the forward gas and projectile velocities.

[0029] The system for measuring the interior ballistics of light gas guns and artillery can obtain complete velocity curve data for the forward gas and projectile, respectively, because it uses long-wave and short-wave dual-wavelength continuous wave measurement, and is not affected by the forward gas. Since microwaves have a longer wavelength, they are less affected by the surface roughness and shape of the projectile, and the bandwidth requirement for the signal acquisition and recording system is low, less than 20MHz. Due to the use of heterodyne up-conversion, in time-frequency analysis, the window time is shorter for the same number of signal fringes, thereby achieving higher time resolution. Due to the use of a high-gain antenna, and the fact that the launch tube of the artillery / light gas gun is equivalent to a waveguide for microwaves, it is possible to measure targets within a long-tube launch tube.

[0030] The system and method for measuring interior ballistics of light gas guns and artillery according to the present invention adopt dual wavelength, heterodyne up-conversion, I / Q demodulation and other technologies to achieve long-distance, continuous, high time resolution, and multi-target measurement.

[0031] The system and method for measuring interior ballistics of light gas guns and artillery, based on heterodyne up-conversion and simultaneous dual-wavelength measurement, can simultaneously and continuously measure the projectile velocity curve and the forward gas velocity curve throughout the launch tube, compared to traditional measurement methods. These systems and methods offer high time resolution, minimal influence from projectile surface roughness and shape, low bandwidth requirements for the signal acquisition and recording system, a simple test layout, inexpensive test consumables, and the ability to measure even long launch tubes, thus avoiding the shortcomings of traditional measurement methods. These systems and methods have broad application prospects in light gas gun / artillery development, trajectory calculation, commissioning, diagnosis and evaluation of abnormal phenomena, and research on the state of high-velocity ionized gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0033] Figure 1 FIG. 1 is a schematic diagram illustrating a system for measuring interior ballistics of a light gas gun and a gun according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the present patent application specification and claims do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a limitation of quantity, but rather denote the presence of at least one.

[0036] Figure 1 FIG. 1 is a schematic diagram illustrating a system for measuring interior ballistics of a light gas gun and a gun according to an embodiment of the present invention.

[0037] like Figure 1As shown, a system for measuring the interior ballistics of light gas guns and artillery, wherein the targets to be measured include the high-speed moving forward gas to be measured and the projectile to be measured in the interior ballistics of the light gas gun or artillery, and the system includes: a first microwave source assembly 101, a first power amplifier 102, a first circulator 103, a horn antenna 104, a second microwave source assembly 107, a second power amplifier 108, a second circulator 109, a linearly polarized antenna 110 and a microwave reflection and transmission plate 113.

[0038] First microwave source assembly 101 generates single-frequency, continuous microwaves (shortwave microwaves) for subsequent measurements. First power amplifier 102, connected to first microwave source assembly 101, receives the microwaves generated by first microwave source assembly 101, amplifies their power, and outputs high-power microwaves for transmission toward the target under test, thereby reflecting a strong signal back from the target.

[0039] The first circulator 103 is used for unidirectional microwave transmission and has a first port, a second port, and a third port. The first port of the first circulator 103 receives the microwave output by the first power amplifier 102 and outputs the microwave through the second port.

[0040] The horn antenna 104 receives the microwaves output by the second port of the first circulator 103, and directionally transmits microwaves to the pre-charge gas 114 to be measured and the projectile 115 to be measured, while receiving the microwave signals reflected from the pre-charge gas 114 to be measured and the projectile 115 to be measured, and returns them to the second port of the first circulator 103; the first circulator 103 outputs the microwave signals returned from the target to be measured and received by the horn antenna 104 through the third port, and utilizes the unidirectional transmission characteristics of the circulator in combination with the rear-end horn antenna 104 to realize microwave transmission and reception with the same antenna, thus realizing an integrated antenna transmitter and receiver.

[0041] Second microwave source assembly 107 generates single-frequency, continuous, long-wave microwaves for subsequent measurements. Second power amplifier 108, connected to second microwave source assembly 107, receives the microwaves generated by second microwave source assembly 107, amplifies their power, and outputs high-power microwaves for transmission toward the target under test, thereby reflecting a strong signal back from the target.

[0042] The second circulator 109 is used for unidirectional microwave transmission and has a first port, a second port and a third port. The first port of the second circulator 109 receives the microwave output by the second power amplifier 108 and outputs the microwave through the second port.

[0043] The linearly polarized antenna 110 receives the microwaves output by the second port of the second circulator 109, and directionally transmits microwaves to the pre-charge gas 114 to be measured and the projectile 115 to be measured. At the same time, it receives the microwave signals reflected from the pre-charge gas 114 to be measured and the projectile 115 to be measured, and returns them to the second port of the second circulator 109; the second circulator 109 outputs the microwave signals returned from the target to be measured and received by the horn antenna 104 through the third port. By utilizing the unidirectional transmission characteristics of the circulator and combining it with the rear-end linearly polarized antenna 110, the same antenna realizes microwave transmission and reception, realizing an integrated antenna transmitter and receiver.

[0044] The microwave reflection and transmission plate 113 is a metal mesh structure, which is used to allow the short-wavelength microwaves emitted by the horn antenna 104 to directly transmit through and reach the target to be measured; and to allow the long-wavelength microwaves emitted by the linear polarization antenna 110 to be reflected at a 45° angle and reach the target to be measured.

[0045] The directions of microwaves emitted by the horn antenna 104 and the linear polarized antenna 110 form an angle of 90°, and the microwave reflective and transmissive plate 113 is disposed on the bisector of the angle formed by the horn antenna 104 and the linear polarized antenna 110 .

[0046] Given the varying transmittances of high-speed fore-flow gas to microwaves of different wavelengths, the present system and method for measuring interior ballistics of light-gas guns and artillery proposes a dual-wavelength, heterodyne up-conversion, and shared-transmission microwave interferometry system. A reflective-transmissive plate, designed to reflect long wavelengths and transmit short wavelengths, is designed and utilized for dual-wavelength measurement. Taking advantage of the varying reflectivity and transmittances of high-speed ionized fore-flow gas to microwaves of different wavelengths, one wavelength is used to measure the projectile velocity through the fore-flow gas, while the other wavelength is used to measure the velocity of the high-speed fore-flow gas. The heterodyne up-conversion design increases the number of interference fringes per unit time, thereby improving temporal resolution. Key features include: 1) simultaneous and continuous measurement of the projectile and fore-flow gas velocities within the launch tube; 2) high temporal resolution; 3) capability for measuring targets within long launch tubes; 4) minimal impact from projectile surface roughness and shape, requiring low bandwidth for the signal acquisition and recording system, simplifying the test layout and maximizing cost-effective consumables; and 5) convenient switching between single- and dual-wavelength modes to meet testing needs.

[0047] According to one or some embodiments of the present invention, the system for light gas gun and artillery interior ballistics measurement further includes: a first reference microwave source 105 , a first mixer 106 , a second reference microwave source 111 and a second mixer 112 .

[0048] The first reference microwave source 105 is used to generate microwaves. The difference between the frequency of the microwaves outputted by the first reference microwave source assembly 105 and the microwave frequency of the first microwave source assembly 101 does not exceed 10 MHz. The generated microwaves are used to output as local oscillator signals for the subsequent first mixer 106 .

[0049] The first circulator 103 transmits the microwave signal returned from the target to be measured and received by the horn antenna 104 to the first mixer 106 via the third port of the first circulator 103. The first mixer 106 receives the local oscillator signal input by the first reference microwave source 105 and the microwave signal output by the third port of the first circulator 103, and mixes them to obtain a signal containing a Doppler frequency shift signal.

[0050] The second reference microwave source 111 is used to generate microwaves. The difference between the frequency of the microwaves outputted by the second microwave source assembly 107 and the microwave frequency thereof does not exceed 10 MHz. The generated microwaves are used to output as local oscillator signals for the subsequent second mixer 112 .

[0051] The second circulator 109 transmits the microwave signal returned from the target to be measured and received by the linearly polarized antenna 110 to the second mixer 112 via the third port of the second circulator 109. The second mixer 112 receives the local oscillator signal input by the second reference microwave source 111 and the microwave signal output by the third port of the second circulator 109, and mixes them to obtain a signal including a Doppler frequency shift signal.

[0052] According to one or some embodiments of the present invention, the system for measuring interior ballistics of a light gas gun and artillery further includes a low-frequency signal amplifier 116. The low-frequency signal amplifier 116 is configured to receive the low-frequency signals including the Doppler shift signals output by the first mixer 106 and the second mixer 112, respectively, and amplify the signals.

[0053] According to one or some embodiments of the present invention, the system for measuring interior ballistics of light gas guns and artillery further includes an oscilloscope 117. The oscilloscope 117 is used to receive the output signal of the low-frequency signal amplifier 116 and perform data acquisition and storage.

[0054] According to one or some embodiments of the present invention, in a system for measuring interior ballistics of light gas guns and artillery, the frequency of the single-frequency continuous microwaves generated by the first microwave source assembly 101 is above 20 GHz; the frequency of the single-frequency continuous microwaves generated by the second microwave source assembly 107 is below 10 GHz, wherein the wavelength of the single-frequency continuous microwaves generated by the second microwave source assembly 107 is longer than the wavelength of the single-frequency continuous microwaves generated by the first microwave source assembly 101.

[0055] The system for measuring the interior ballistics of light gas guns and artillery can obtain complete velocity curve data for the forward gas and projectile, respectively, because it uses long-wave and short-wave dual-wavelength continuous wave measurement, and is not affected by the forward gas. Since microwaves have a longer wavelength, they are less affected by the surface roughness and shape of the projectile, and the bandwidth requirement for the signal acquisition and recording system is low, less than 20MHz. Due to the use of heterodyne up-conversion, in time-frequency analysis, the window time is shorter for the same number of signal fringes, thereby achieving higher time resolution. Due to the use of a high-gain antenna, and the fact that the launch tube of the artillery / light gas gun is equivalent to a waveguide for microwaves, it is possible to measure targets within a long-tube launch tube.

[0056] According to another aspect of the present invention, a method for measuring interior ballistics of a light gas gun and a cannon is provided. The method is implemented based on the above system for measuring interior ballistics of a light gas gun and a cannon, wherein the method comprises the following steps:

[0057] S1. The first microwave source assembly 101 generates a single-frequency continuous microwave, which is transmitted to the first power amplifier 102 via a transmission line including a high-frequency cable; the second microwave source assembly 107 generates a single-frequency continuous microwave, which is transmitted to the second power amplifier 108 via a transmission line including a high-frequency cable.

[0058] S2, the first power amplifier 102 amplifies the power of the received microwaves, and the amplified microwaves are transmitted to the first port of the first circulator 103 via the transmission line; the second power amplifier 108 amplifies the power of the received microwaves, and the amplified microwaves are transmitted to the first port of the second circulator 109 via the transmission line.

[0059] S3. After receiving the microwave, the first port of the first circulator performs unidirectional transmission, outputs it through the second port of the first circulator 103, and then transmits it to the horn antenna 104 through the transmission line. After receiving the microwave, the first port of the second circulator performs unidirectional transmission, outputs it through the second port of the second circulator 109, and then transmits it to the linearly polarized antenna 110 through the transmission line.

[0060] S4. After receiving the microwaves, the horn antenna 104 emits the microwaves into space. After being transmitted through space, the microwaves are transmitted through the microwave reflection and transmission plate 113 and reach the surface of the moving target to be measured. After being reflected by the target to be measured, the microwaves are transmitted through space and then received by the horn antenna 104. After receiving the microwaves, the linearly polarized antenna 110 emits the microwaves into space. After being transmitted through space, the microwaves are reflected through the microwave reflection and transmission plate 113 and reach the surface of the moving target to be measured. After being reflected by the target to be measured, the microwaves are transmitted through space and then received by the linearly polarized antenna 110.

[0061] S5. After the horn antenna 104 receives microwaves from space, it transmits them to the second port of the first circulator via the transmission line. After the linearly polarized antenna 110 receives microwaves from space, it transmits them to the second port of the second circulator via the transmission line.

[0062] S6. The second port of the first circulator receives the microwave signal returned from the antenna. The signal is transmitted unidirectionally within the circulator and output from the third port of the first circulator via the transmission line to the signal input port of the first mixer 106. The second port of the second circulator receives the microwave signal returned from the antenna. The signal is transmitted unidirectionally within the circulator and output from the third port of the second circulator via the transmission line to the signal input port of the second mixer 112.

[0063] According to one or some embodiments of the present invention, the method for measuring the interior ballistics of light gas guns and artillery also includes the following steps: S7, after the first mixer 106 receives a signal from the first circulator, it mixes it with the microwave received from the first reference microwave source 105 to obtain a signal containing a Doppler frequency shift signal, and the signal is transmitted to the low-frequency signal amplifier 116 via a transmission line; after the second mixer 112 receives a signal from the second circulator, it mixes it with the microwave received from the second reference microwave source 111 to obtain a signal containing a Doppler frequency shift signal, and the signal is transmitted to the low-frequency signal amplifier 116 via a transmission line.

[0064] According to one or some embodiments of the present invention, the method for measuring interior ballistics of light gas guns and artillery further includes the following step: S8, the low-frequency signal amplifier 116 amplifies the received low-frequency signals respectively, and transmits the amplified signals to the oscilloscope 117.

[0065] According to one or some embodiments of the present invention, the method for measuring interior ballistics of light gas guns and artillery guns further includes the step: S9, the oscilloscope 117 collects and stores the received signals.

[0066] According to one or some embodiments of the present invention, the method for measuring interior ballistics of light gas guns and artillery further comprises the step: S10, performing data processing by a computer to obtain a curve / data of the velocity variation of the target to be measured over time.

[0067] The computer performs data processing including the following calculation methods:

[0068] Assume that the frequency of microwave output by the microwave source component is , the frequency of the microwave carrying Doppler shift information output from the third port of the circulator is , where the target moves towards the antenna and takes a + sign, and moves away from the antenna and takes a - sign; let the frequency of the microwave output by the reference microwave source be , is the up-conversion value, that is, the frequency value to which the Doppler signal needs to be "moved" , the signal frequency output after the mixer , we can get the "apparent" speed Formula (1); the actual speed of the target is , The frequency is The microwave wavelength corresponding to the microwave source component;

[0069] (1)

[0070] , corresponds to the "apparent" speed of the target when it is stationary, where , and the target moves toward the antenna, the actual speed of the target can be calculated using formula (2):

[0071] (2)

[0072] The data processing using the time-frequency analysis method includes the following steps:

[0073] S11. Calculate the target's apparent speed when stationary ;

[0074] S12, performing time-frequency analysis on the signal data to obtain a time-frequency spectrum diagram;

[0075] S13, extract the time-frequency curve data and calculate the "apparent" speed by formula (1) ;

[0076] S14. Calculate the speed data of the target to be measured using formula (2).

[0077] The data processing using the orthogonal signal I / Q demodulation method includes the following steps:

[0078] S21. Calculate the target's apparent speed when stationary ;

[0079] S22, calculating the phase of the signal;

[0080] S23. Differentiate the phase and calculate the "apparent" velocity ;

[0081] S24. Calculate the speed data of the target to be measured using formula (2).

[0082] Among them, since long-wave and short-wave dual-wavelength continuous wave measurement is used, complete velocity curve data of the forward gas and projectile can be obtained respectively, and are not affected by the forward gas; since the wavelength of microwaves is longer, it is less affected by the surface roughness and shape of the projectile, and the bandwidth requirement for the signal acquisition and recording system is low, less than 20MHz; since heterodyne up-conversion is used, in time-frequency analysis, the window time is shorter for the same number of signal stripes, thus having higher time resolution; since a high-gain antenna is used, and for microwaves, the launch tube of an artillery or light gas gun is equivalent to a waveguide, it is possible to measure targets inside a long-tube launch tube.

[0083] The system and method for measuring interior ballistics of light gas guns and artillery according to the present invention adopt dual wavelength, heterodyne up-conversion, I / Q demodulation and other technologies to achieve long-distance, continuous, high time resolution, and multi-target measurement.

[0084] The operating principle of the present invention is as follows: The system designed in this invention comprises two independent microwave interferometer velocimetry units, each utilizing different wavelengths. These units share a microwave reflective-transmissive plate 113, a low-frequency signal amplifier 116, and a data acquisition and recording unit, such as an oscilloscope 117. Each microwave interferometer velocimetry unit consists of a microwave source assembly, a power amplifier, a circulator, an antenna, a reference microwave source, and a mixer. Utilizing the Doppler effect, the unit can measure the velocity of a moving target. A certain frequency difference exists between the microwave source assembly and the reference microwave source in each velocimetry unit. Heterodyne up-conversion of the Doppler-shifted signal is achieved in the mixer, enabling high temporal resolution during signal processing. The reflective-transmissive plate is designed by exploiting the polarization properties of microwaves and the transmission characteristics of short-wavelength microwaves through metal mesh. The long-wavelength velocimetry unit uses a linearly polarized antenna 110 to transmit microwaves, which are reflected by the reflective-transmissive plate. The short-wavelength velocimetry unit's antenna emits microwaves with a shorter wavelength, which are transmitted by the reflective-transmissive plate. The long-wave and short-wave antennas are angled at 90°, and the reflective-transmissive plate is at a 45° angle to the two antennas. This allows microwaves of both wavelengths to travel along the same path to the target. This invention primarily measures the interior ballistics of artillery / light-gas guns. In a dual-wavelength microwave transmission tube, the long-wavelength microwaves are reflected by the front surface of the forward gas, while the short-wavelength microwaves penetrate the forward gas and are emitted by the projectile surface, enabling simultaneous measurement of both the forward gas and projectile velocities.

[0085] According to one or some embodiments of the present invention, the specific working process is as follows:

[0086] The shortwave microwaves emitted by the first microwave source assembly 101 are amplified by the first power amplifier 102 and input to the first port of the first circulator 103. The shortwave microwaves are then output to the horn antenna 104 through the second port. The microwaves emitted by the horn antenna 104 are transmitted through the reflective and transmissive plate and then through the pre-charge gas to be tested 114. The microwaves are transmitted to the surface of the projectile to be tested 115. The microwaves reflected by the surface of the projectile to be tested 115 undergo a Doppler frequency shift and are then transmitted along the previous transmission path to the second port of the first circulator. The shortwave microwaves are then output to the signal terminal of the first mixer 106 through the third port. The first reference microwave source 105 directly outputs the signal to the local oscillator terminal of the first mixer 106. The Doppler frequency shift signal after interference by the mixer is output to the low-frequency signal amplifier 116 for amplification. The amplified signal is collected and recorded by the oscilloscope 117 to obtain the up-converted Doppler frequency shift signal of the projectile in the interior ballistics of the artillery / light gas gun.

[0087] The long-wave microwaves emitted by the second microwave source assembly 107 are amplified by the second power amplifier 108 and input to the first port of the second circulator 109. The microwaves are then output from the second port to the linearly polarized antenna 110. The microwaves emitted by the linearly polarized antenna 110 are reflected by the reflective-transmissive plate and transmitted to the front surface of the forward gas 114 to be measured. After reflection from this surface, the microwaves undergo a Doppler frequency shift and are then transmitted along the previous transmission path to the second port of the second circulator. Finally, they are output from the third port to the signal terminal of the second mixer 112. The Doppler frequency shift signal directly outputted to the local oscillator terminal of the second mixer 112 is referenced by the second microwave source. After interference with the mixer, the Doppler frequency shift signal is output to the low-frequency signal amplifier 116 for amplification. The amplified signal is then acquired and recorded by the oscilloscope 117. This results in an up-converted Doppler frequency shift signal of the forward gas in the interior trajectory of the artillery / light gas gun.

[0088] By processing the above signals, we can obtain the curves / data of the velocity of the projectile and the forward gas changing with time.

[0089] The longwave microwaves used in the present invention typically have a frequency below 10 GHz, while the shortwave microwaves typically have a frequency above 20 GHz. The frequency difference between the reference microwave source used for heterodyne upconversion and the corresponding test microwave signal typically does not exceed 10 MHz, and the reference microwave source frequency is lower than the corresponding test microwave signal. Consequently, the bandwidth of the measured Doppler shift signal after upconversion does not exceed 20 MHz.

[0090] The present invention utilizes a linearly polarized high-gain horn antenna 104 as both a longwave transceiver and a shortwave transceiver. This allows for the design of a reflective and transmissive metal mesh structure, enabling dual wavelengths to be transmitted along the same path into the artillery / light gas gun launch tube. Furthermore, the integrated transceiver antenna avoids the measurement errors associated with separate antennas due to the angle between them, allowing the high-gain antenna to measure targets within long launch tubes.

[0091] The system and method for measuring interior ballistics of light gas guns and artillery, based on heterodyne up-conversion and simultaneous dual-wavelength measurement, can simultaneously and continuously measure the projectile velocity curve and the forward gas velocity curve throughout the launch tube, compared to traditional measurement methods. These systems and methods offer high time resolution, minimal influence from projectile surface roughness and shape, low bandwidth requirements for the signal acquisition and recording system, a simple test layout, inexpensive test consumables, and the ability to measure even long launch tubes, thus avoiding the shortcomings of traditional measurement methods. These systems and methods have broad application prospects in light gas gun / artillery development, trajectory calculation, commissioning, diagnosis and evaluation of abnormal phenomena, and research on the state of high-velocity ionized gases.

[0092] 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. The scope of protection of the present invention is determined by the appended claims.

Claims

1. A system for measuring interior ballistics of light gas guns and artillery, wherein: The target to be measured includes a high-speed moving forward gas to be measured and a projectile to be measured in the internal ballistics of a light gas gun or a gun. The system includes: The first microwave source assembly is used to generate single-frequency continuous microwaves, which are short-wave microwaves, for subsequent measurements; a first power amplifier connected to the first microwave source assembly, receiving the microwaves generated by the first microwave source assembly, performing power amplification, and outputting microwaves with a relatively high power for transmitting toward the target to be measured, thereby enabling a relatively strong signal to be reflected back from the target to be measured; a first circulator, for unidirectional microwave transmission, having a first port, a second port, and a third port, wherein the first port of the first circulator receives the microwave output by the first power amplifier and outputs the microwave through the second port; The horn antenna receives the microwaves output by the second port of the first circulator, and directionally transmits the microwaves toward the pre-charge gas and the projectile to be tested, while receiving the microwave signals reflected from the pre-charge gas and the projectile to be tested and returning them to the second port of the first circulator. The first circulator outputs the microwave signals returned from the target to be tested and received by the horn antenna through the third port. By utilizing the unidirectional transmission characteristics of the circulator and combining it with the rear-end horn antenna, the same antenna realizes microwave transmission and reception, thus realizing an integrated antenna transmitter and receiver. The second microwave source assembly is used to generate single-frequency continuous microwaves, which are long-wave microwaves, for subsequent measurements; a second power amplifier connected to the second microwave source assembly, receiving the microwaves generated by the second microwave source assembly, performing power amplification, and outputting microwaves with a relatively high power for transmitting toward the target to be measured, thereby enabling a relatively strong signal to be reflected back from the target to be measured; a second circulator, for unidirectional microwave transmission, having a first port, a second port, and a third port, wherein the first port of the second circulator receives the microwave output by the second power amplifier and outputs the microwave through the second port; The linearly polarized antenna receives the microwaves output by the second port of the second circulator, and directionally transmits the microwaves toward the pre-charge gas and the projectile to be tested, while receiving the microwave signals reflected from the pre-charge gas and the projectile to be tested and returning them to the second port of the second circulator. The second circulator outputs the microwave signals returned from the target to be tested and received by the horn antenna through the third port. By utilizing the unidirectional transmission characteristics of the circulator and combining it with the rear-end linearly polarized antenna, the same antenna can realize microwave transmission and reception, thus realizing an integrated antenna transmitter and receiver. The microwave reflection and transmission plate is a metal mesh structure, which is used to allow the short-wavelength microwaves emitted by the horn antenna to directly transmit through and reach the target to be measured; and to allow the long-wavelength microwaves emitted by the linear polarization antenna to be reflected at a 45° angle and reach the target to be measured. The directions of microwaves emitted by the horn antenna and the linear polarization antenna form an angle of 90°, and the microwave reflection and transmission plate is arranged on the bisector of the angle formed by the horn antenna and the linear polarization antenna.

2. The system for light gas gun and artillery interior ballistics measurement according to claim 1, wherein: Also includes: a first reference microwave source for generating microwaves, wherein the difference between the frequency of the microwaves output by the first microwave source component and the microwave frequency of the first microwave source component does not exceed 10 MHz, and the generated microwaves are used to output a local oscillator signal for a subsequent first mixer; a first mixer, wherein the first circulator transmits the microwave signal received by the horn antenna and returned from the target to be measured to the first mixer via the third port of the first circulator, and the first mixer receives the local oscillator signal input by the first reference microwave source and the microwave signal output by the third port of the first circulator, performs mixing, and obtains a signal including a Doppler frequency shift signal; a second reference microwave source for generating microwaves, wherein the difference between the frequency of the microwaves outputted by the second reference microwave source component and the microwave frequency of the second reference microwave source component does not exceed 10 MHz, and the generated microwaves are used to output a local oscillator signal for a subsequent second frequency mixer; The second mixer transmits the microwave signal received from the linearly polarized antenna and returned from the target to be measured to the second mixer via the third port of the second circulator. The second mixer receives the local oscillator signal input from the second reference microwave source and the microwave signal output from the third port of the second circulator, performs mixing, and obtains a signal including a Doppler frequency shift signal.

3. The system for light gas gun and artillery interior ballistics measurement according to claim 2, wherein: Also includes: The low-frequency signal amplifier is used to receive the low-frequency signals containing Doppler frequency shift signals output by the first mixer and the second mixer respectively, and amplify the signals respectively.

4. The system for light gas gun and artillery interior ballistics measurement according to claim 3, wherein: Also includes: The oscilloscope is used to receive the output signal of the low-frequency signal amplifier and perform data acquisition and storage.

5. The system for light gas gun and artillery interior ballistics measurement according to claim 1, wherein: The single-frequency continuous microwave frequency generated by the first microwave source assembly is above 20 GHz; the single-frequency continuous microwave frequency generated by the second microwave source assembly is below 10 GHz, wherein the single-frequency continuous microwave wavelength generated by the second microwave source assembly is longer than the single-frequency continuous microwave wavelength generated by the first microwave source assembly.

6. A method for measuring interior ballistics of a light gas gun and a cannon, the method being implemented based on the system for measuring interior ballistics of a light gas gun and a cannon according to any one of claims 1 to 5, wherein: The method comprises the following steps: S1. A first microwave source assembly generates a single-frequency continuous microwave, which is transmitted to a first power amplifier via a transmission line including a high-frequency cable; a second microwave source assembly generates a single-frequency continuous microwave, which is transmitted to a second power amplifier via a transmission line including a high-frequency cable; S2, the first power amplifier amplifies the power of the received microwave, and the amplified microwave is transmitted to the first port of the first circulator via the transmission line; the second power amplifier amplifies the power of the received microwave, and the amplified microwave is transmitted to the first port of the second circulator via the transmission line; S3, after receiving the microwave at the first port of the first circulator, the microwave is transmitted unidirectionally, outputted through the second port of the first circulator, and then transmitted to the horn antenna via the transmission line; After the first port of the second circulator receives the microwave, it performs unidirectional transmission, is output through the second port of the second circulator, and then is transmitted to the linearly polarized antenna through the transmission line; S4. After receiving the microwave, the horn antenna emits the microwave into space. After being transmitted through space, the microwave is transmitted from the microwave reflection and transmission plate and reaches the surface of the moving target to be measured. After being reflected by the target to be measured, the microwave is transmitted through space and then received by the horn antenna. After receiving the microwave, the linearly polarized antenna emits the microwave into space. After being transmitted through space, the microwave is reflected from the microwave reflection and transmission plate and reaches the surface of the moving target to be measured. After being reflected by the target to be measured, the microwave is transmitted through space and then received by the linearly polarized antenna. S5. After the horn antenna receives microwaves from space, it transmits them to the second port of the first circulator via the transmission line. After the linearly polarized antenna receives microwaves from space, it transmits them to the second port of the second circulator via the transmission line. S6. The second port of the first circulator receives the microwave signal returned from the antenna. The signal is transmitted unidirectionally within the circulator and output from the third port of the first circulator to the signal input port of the first mixer via the transmission line. The second port of the second circulator receives the microwave signal returned from the antenna. The signal is transmitted unidirectionally within the circulator and output from the third port of the second circulator to the signal input port of the second mixer via the transmission line.

7. The method for measuring interior ballistics of a light gas gun and a gun according to claim 6, wherein: Also includes the steps: S7. After receiving a signal from the first circulator, the first mixer performs mixing processing on the signal and the microwave received from the first reference microwave source to obtain a signal containing a Doppler frequency shift signal, which is transmitted to the low-frequency signal amplifier via the transmission line. After receiving a signal from the second circulator, the second mixer performs mixing processing on the signal and the microwave received from the second reference microwave source to obtain a signal containing a Doppler frequency shift signal, which is transmitted to the low-frequency signal amplifier via the transmission line.

8. The method for measuring interior ballistics of a light gas gun and a cannon according to claim 7, wherein: Also includes the steps: S8, the low-frequency signal amplifier amplifies the received low-frequency signals, and the amplified signals are transmitted to the oscilloscope.

9. The method for measuring interior ballistics of a light gas gun and a cannon according to claim 8, wherein: Also includes the steps: S9. The oscilloscope collects and stores the received signal.

10. The method for measuring interior ballistics of a light gas gun and a gun according to claim 9, wherein: Also includes the steps: S10, the computer processes the data to obtain a curve / data showing the speed of the target to be measured changing with time, The computer performs data processing including the following calculation methods: Assume that the frequency of microwave output by the microwave source component is , the frequency of the microwave carrying Doppler shift information output from the third port of the circulator is , where the target moves towards the antenna and takes a + sign, and moves away from the antenna and takes a - sign; let the frequency of the microwave output by the reference microwave source be , is the up-conversion value, that is, the frequency value to which the Doppler signal needs to be "moved" , the signal frequency output after the mixer , we can get the "apparent" speed Formula (1); the actual speed of the target is , The frequency is The microwave wavelength corresponding to the microwave source component; （1） , corresponds to the "apparent" speed of the target when it is stationary, where , and the target moves toward the antenna, the actual speed of the target can be calculated using formula (2): （2） The data processing using the time-frequency analysis method includes the following steps: S11. Calculate the "apparent" speed of the target when it is stationary ; S12, performing time-frequency analysis on the signal data to obtain a time-frequency spectrum diagram; S13, extract the time-frequency curve data and calculate the "apparent" speed by formula (1) ; S14, calculate the speed data of the target to be measured by formula (2); The data processing using the orthogonal signal I / Q demodulation method includes the following steps: S21. Calculate the target's apparent speed when stationary ; S22, calculating the phase of the signal; S23. Differentiate the phase and calculate the "apparent" velocity ; S24, calculate the speed data of the target to be measured by formula (2); Among them, since long-wave and short-wave dual-wavelength continuous wave measurement is used, complete velocity curve data of the forward gas and projectile can be obtained respectively, and are not affected by the forward gas; since the wavelength of microwaves is longer, it is less affected by the surface roughness and shape of the projectile, and the bandwidth requirement for the signal acquisition and recording system is low, less than 20MHz; since heterodyne up-conversion is used, in time-frequency analysis, the window time is shorter for the same number of signal stripes, thus having higher time resolution; since a high-gain antenna is used, and for microwaves, the launch tube of an artillery or light gas gun is equivalent to a waveguide, it is possible to measure targets inside a long-tube launch tube.

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