Photoacoustic detection combined light curtain projectile speed and target landing coordinate measuring device and method

Abstract

The invention belongs to the field of outer ballistic parameter measurement, and particularly relates to a photoacoustic detection combined light curtain projectile speed and target landing coordinate measuring device and a photoacoustic detection combined light curtain projectile speed and target landing coordinate measuring method. The device comprises a double-rectangular-ring photoacoustic detection combined light curtain and a second detection light curtain which are parallel to each other and are used for collecting bullet curtain passing signals and shock wave signals thereof; the double-rectangular-ring photoacoustic detection combined light curtain comprises a first detection light curtain in the same plane and two rectangular-ring photoacoustic detection devices arranged on the periphery of the first detection light curtain in a sleeving mode at an interval S. The measurement method comprises the following steps: acquiring a shock wave signal of a projectile; calculating an apparent velocity component of the shock wave in the double-rectangular-ring photoacoustic detection combined light curtain; solving the coordinates of the flying projectile in the double-rectangular-ring photoacoustic detection combined light curtain; calculating an included angle between the shock wave and the double-rectangular-ring photoacoustic detection combined light curtain and a half shock wave angle of the projectile; the pitch angle theta and the azimuth angle gamma of the flying projectile penetrating through the double-rectangular-ring photoacoustic detection combined light curtain are calculated; and solving the velocity vector of the flying projectile. The measuring device is simple in structure, the measuring method is easy to implement, the incident condition and aperture of the measured projectile are not required, and the triggering uniqueness of the rectangular ring photoacoustic detection device can be ensured.

Description

Technical Field

[0001] The invention belongs to the field of exterior ballistic parameter measurement, and in particular relates to a device and method for measuring projectile velocity and target coordinates by combining photoacoustic detection with a light curtain. Background Art

[0002] The external ballistic parameters of supersonic projectiles are important technical indicators for evaluating the performance of supersonic weapons, and provide an important reference for optimizing the design and production of light weapons. The mainstream methods for measuring external ballistic parameters are: light curtain array measurement method, acoustic array measurement method, and radar measurement method.

[0003] Light curtain arrays are divided into two types: passive and active. The passive type uses the sky as the background light source, which is affected by the measurement environment and cannot be used all-weather. The active type uses stable artificial light sources such as array LED lights as the background light. The sensing detection light curtain is stable and has high measurement accuracy. However, the supersonic projectile is accompanied by the existence of attached shock waves along the trajectory. The attached shock waves will reach the detection light curtain before the warhead. If the detection light curtain trigger voltage is set unreasonably, it will cause false triggering or multiple light curtain time difference recognition errors. The acoustic array measurement method is flexible and changeable, and the sensor module is easy to build. It has good measurement capabilities for long-distance external ballistic parameter measurements, but it is easy to have signal confusion in the measurement of external ballistic parameters of projectiles in short-distance or low-body trajectories, which increases the difficulty of signal recognition. The radar measurement method often uses the Doppler effect as the measurement principle to measure the external ballistic parameters of the projectile. Its accuracy is high, but the measurement calculation is complex, and the cost is high and maintenance is difficult.

[0004] Patent "ZL202211450015.9" constructs a sensor measurement module based on the principle of interferometric measurement, which has high measurement accuracy, but it is difficult to construct an interferometric measurement optical path and ensure that all its optical paths are in the same measurement plane, and the cost of the sensing part is high, and it is impossible to measure the projectile's outer ballistic parameters at any incident angle. Patent "ZL202310065193.8" constructs a sparsely arranged laser transmitting array and a photodetector receiving array to perform sensor measurement, but because the laser optical path is located within the detection surface, there is a bad situation where the projectile passes through the laser optical path and causes false triggering, and the trigger signal of the entire measurement process is obtained by calculation, which introduces an additional error component to the determination of the trigger moment of the trigger signal. Summary of the invention

[0005] The present invention provides a device and method for measuring the velocity and target coordinates of a projectile using a combined photoacoustic detection light curtain, so as to solve the problems of the existing measurement method, namely, the high cost of the sensing part, the inability to measure the outer ballistic parameters of the projectile at any incident angle, false triggering, and the introduction of extra workload in determining the triggering moment.

[0006] To achieve the above-mentioned object, the technical solution adopted by the present invention is: a device for measuring the projectile velocity and target coordinates by using a photoacoustic detection combined light curtain, comprising a double rectangular ring photoacoustic detection combined light curtain and a second detection light curtain parallel to each other and spaced at a distance of H, to collect a projectile passing through the curtain signal and its shock wave signal;

[0007] The double rectangular ring photoacoustic detection combined light curtain comprises a first detection light curtain in the same plane and two rectangular ring photoacoustic detection devices arranged at a distance S outside the first detection light curtain, wherein the inner rectangular ring photoacoustic detection device is arranged at a position that coincides with the edge of the rectangular detection light curtain;

[0008] The rectangular ring photoacoustic detection device is composed of four linear photoacoustic detectors, which are composed of a linear laser emitter and a photoelectric detector with a spacing of L. The four linear photoacoustic detectors constitute the four sides of a rectangle.

[0009] Furthermore, the specific structure of the above-mentioned rectangular ring photoacoustic detection device is as follows: four linear laser emitters are distributed at the four corners of the rectangle, and adjacent linear laser emitters are arranged perpendicular to each other in space; four photodetectors are distributed at the four corners of the rectangle, and adjacent photodetectors are arranged perpendicular to each other in space; the linear laser emitters and photodetectors arranged on the same side form a linear photoacoustic detector with a spacing of L, and the four groups of linear laser emitters and photodetectors at the four corners of the rectangle constitute a rectangular ring photoacoustic detection device.

[0010] Furthermore, the specific structure of the above-mentioned rectangular ring photoacoustic detection device is as follows: four linear laser emitters are divided into two groups and are symmetrically distributed on the diagonals of the rectangle, two linear laser emitters are distributed perpendicularly to each other at one corner of the rectangle, and the other group of linear laser emitters is distributed at corresponding positions on the diagonal corner; four photoelectric detectors are arranged in the form of four linear laser emitters, and each group of photoelectric detectors and each group of linear laser emitters are arranged orthogonally to each other at the four corners of the rectangle.

[0011] A method for measuring the velocity and target coordinates of a projectile using a photoacoustic detection combined light curtain based on the above device includes the following steps:

[0012] Step 1: The projectile passes through the first detection light curtain of the double rectangular ring photoacoustic detection combined light curtain, generating a trigger signal, and the two rectangular ring photoacoustic detection devices begin to collect the shock wave signal of the projectile;

[0013] Step 2: Calculate the apparent velocity component v of the shock wave in the double rectangular ring photoacoustic detection combined light curtain according to the arrival time of the shock wave at the two rectangular ring photoacoustic detection devices. x+ 、v x- 、v y+ 、v y- ;

[0014] Step 3, solving the coordinates (x, y) of the flying projectile in the double rectangular ring photoacoustic detection combined light curtain;

[0015] Step 4: Calculate the angle β between the shock wave and the double rectangular ring photoacoustic detection combined light curtain based on the ambient sound velocity x- , β x+ , β y- , β y+ and the half shock angle α of the projectile;

[0016] Step 5, calculating the pitch angle θ and azimuth angle γ of the flying projectile passing through the double rectangular ring photoacoustic detection combined light curtain;

[0017] Step 6: The projectile passes through the first detection light curtain and the second detection light curtain. Combined with the triggering time of the two, the velocity component of the flying projectile in the z direction is calculated, and the velocity vector of the flying projectile is solved according to the pitch angle θ and azimuth angle γ calculated in step 5.

[0018] Furthermore, in the second step above, the apparent velocity component v x+ 、v x- 、v y+ 、v y- The calculation formula is

[0019]

[0020] Wherein, S is the distance between the inner rectangular ring photoacoustic detection device and the outer rectangular ring photoacoustic detection device; v x+ 、v x- 、v y+ 、v y- are the propagation velocity components of the shock wave in the positive x-axis, negative x-axis, positive y-axis, and negative y-axis directions, respectively; t a1 ,t a2 are the arrival times of the shock wave at the left inner linear photoacoustic detector and the left outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain respectively; t c1 ,t c2 are the arrival times of the shock wave at the right inner linear photoacoustic detector and the right outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain, respectively; t b1 ,t b2 are the arrival times of the shock wave reaching the lower inner linear photoacoustic detector and the lower outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain respectively; t d1 ,t d2 They are the arrival times of the shock wave reaching the upper inner linear photoacoustic detector and the upper outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain.

[0021] Furthermore, in the third step above, the coordinate (x, y) of the flying projectile in the double rectangular ring photoacoustic detection combined light curtain is calculated as follows:

[0022]

[0023] Here, t0 is the triggering moment when the flying projectile passes through the first detection light curtain (3).

[0024] Furthermore, in the fourth step, the angle β between the shock wave and the detection light curtain is x- , β x+ , β y- , β y+ The calculation formula is

[0025]

[0026] Among them, c0 is the speed of the shock wave propagating forward along the shock wave surface, that is, the ambient sound speed

[0027] The calculation formula of the projectile's half shock wave angle α is:

[0028]

[0029] Furthermore, in the fifth step, the calculation formula for the pitch angle θ and azimuth angle γ of the flying projectile passing through the double rectangular ring photoacoustic detection combined light curtain is:

[0030]

[0031] Among them, γ2 is the pitch projection angle;

[0032] tanθ=cosγtanγ2(6)

[0033] Furthermore, in the sixth step, the calculation formula for calculating the velocity component of the flying projectile in the z direction by the first detection light curtain and the second detection light curtain is:

[0034]

[0035] Among them, t'0 is the triggering moment when the flying projectile passes through the second detection light curtain

[0036]

[0037] Compared with the prior art, the advantages of the present invention are:

[0038] (1) The structure of the measuring device is simple and the measuring method is easy to implement: the linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain in the photoacoustic detection combined light curtain projectile speed and target coordinate measurement device provided by the present invention is fixed in position and has coding characteristics; only two layers of rectangular ring photoacoustic detection devices need to be arranged on the periphery of a detection light curtain to form the sensing part of the double rectangular ring photoacoustic detection combined light curtain, which has the characteristics of convenient and fast construction, easy deployment and low cost; the ambient sound speed is introduced to calculate the angle parameter of the projectile passing through the double rectangular ring photoacoustic detection combined light curtain, and the second light curtain selects the detection light curtain, which simplifies the double light curtain structure and calculates the average speed of the projectile passing through the double light curtain. During the measurement process, there is no need to perform additional judgment on the triggering sequence of the linear photoacoustic detectors, thereby simplifying the measurement process.

[0039] (2) No requirements on the incident conditions and caliber of the projectile being measured: Since the method provided by the present invention can solve the azimuth and elevation angles of non-vertically incident projectiles, the device provided by the present invention has the ability to measure non-vertically incident projectiles, and has no strict requirements on the caliber of the projectile, and the measurement method has wide adaptability.

[0040] (3) The trigger signal is unique: Since the rectangular ring photoacoustic detection device provided by the present invention is arranged around the rectangular detection light curtain, the projectile passing through the double rectangular ring photoacoustic detection combined light curtain only triggers the detection light curtain and has no effect on the rectangular ring photoacoustic detection device. Therefore, the rectangular ring photoacoustic detection device does not have the problem of the projectile other than the shock wave mistakenly triggering the laser light path, thereby improving the reliability of the measurement process and not introducing additional errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is the measurement principle diagram of the method of the present invention;

[0042] Figure 2 This is the measurement principle diagram of xoz projection surface;

[0043] Figure 3 This is the principle diagram of measurement within the YOZ projection plane.

[0044] Figure 4 Another structural schematic diagram of the rectangular ring photoacoustic detection device.

[0045] The reference numerals are as follows:

[0046] 1- linear laser emitter; 2- photoelectric detector; 3- first detection light curtain; 4- rectangular ring photoacoustic detection device; 5- double rectangular ring photoacoustic detection combined light curtain; 6- second detection light curtain. DETAILED DESCRIPTION

[0047] In order to more clearly illustrate the technology of the present invention, the present invention will be described in detail below with reference to relevant drawings and embodiments.

[0048] See also Figure 1 The present embodiment provides a photoacoustic detection combined light curtain projectile velocity and target coordinate measurement device, comprising a double rectangular ring photoacoustic detection combined light curtain 5 and a second detection light curtain 6 parallel to each other and with a spacing of H, for collecting projectile passing curtain signals and shock wave signals thereof;

[0049] The double rectangular ring photoacoustic detection combined light curtain 5 includes a first detection light curtain 3 in the same plane and two rectangular ring photoacoustic detection devices 4 arranged at a distance S outside the first detection light curtain 3, wherein the inner rectangular ring photoacoustic detection device 4 is arranged at a position that coincides with the edge of the first detection light curtain 3;

[0050] The rectangular ring photoacoustic detection device 4 is composed of four linear photoacoustic detectors, which are composed of a linear laser emitter 1 and a photoelectric detector 2 with a spacing L. The four linear photoacoustic detectors constitute the four sides of a rectangle.

[0051] One of the specific structures of the rectangular ring photoacoustic detection device 4 is as follows: four linear laser emitters 1 are distributed at the four corners of the rectangle, and adjacent linear laser emitters 1 are arranged perpendicular to each other in space; four photodetectors 2 are distributed at the four corners of the rectangle, and adjacent photodetectors 2 are arranged perpendicular to each other in space; the linear laser emitters 1 and photodetectors 2 arranged on the same side form a linear photoacoustic detector with a spacing L, and the four groups of linear laser emitters 1 and photodetectors 2 on the four corners of the rectangle constitute a rectangular ring photoacoustic detection device 4.

[0052] In this embodiment, the main optical axis of the inner linear photoacoustic detector on the left side of the double rectangular ring photoacoustic detection combined light curtain 5 is set as the y-axis; the main optical axis of the inner linear photoacoustic detector below is set as the x-axis, and the distance between the inner and outer layers of linear photoacoustic detectors is S; the second detection light curtain is placed at the rear side H, and its measurement principle diagram is as follows Figure 1 shown.

[0053] Based on the above device, the present invention provides a method for measuring the velocity and target coordinates of a combined light curtain projectile using photoacoustic detection, see Figure 2 and Figure 3 , including the following steps:

[0054] In the following description, a, b, c, and d represent the four directions of left, bottom, right, and top, respectively, and 1 and 2 represent the inner and outer linear photoacoustic detectors.

[0055] Step 1: The projectile passes through the double rectangular ring photoacoustic detection combined light curtain 3, generating a trigger signal, and the inner linear photoacoustic detector and the outer linear photoacoustic detector begin to collect the shock wave signal of the projectile;

[0056] The flying projectile passes through the first detection light curtain 3, and the shock wave propagates in the double rectangular ring photoacoustic detection combined light curtain 5 and reaches the two linear photoacoustic detectors on the left. The arrival times are t a1,t a2 , v x- is the negative propagation speed of the x-axis; it passes through the two linear photoacoustic detectors on the right in turn, and the arrival times are t c1 ,t c2 , v x+ is the forward propagation speed of the x-axis; it passes through the two linear photoacoustic detectors below in sequence, and the arrival times are t b1 ,t b2 , v y- is the negative propagation velocity of the y-axis; it passes through the two linear photoacoustic detectors above in sequence, and the arrival times are t d1 ,t d2 , v y+ is the positive propagation velocity on the y-axis.

[0057] Step 2: Calculate the apparent velocity component v of the shock wave in the detection light curtain based on the arrival time of the inner linear photoacoustic detector and the outer linear photoacoustic detector at the shock wave. x+ 、v x- 、v y+ 、v y- :

[0058] The apparent velocity component v x+ 、v x- 、v y+ 、v y- The calculation formula is

[0059]

[0060] Step 3: Calculate the coordinates (x, y) of the flying projectile in the double rectangular ring photoacoustic detection combined light curtain 5:

[0061] The coordinate (x, y) calculation formula of the flying projectile in the double rectangular ring photoacoustic detection combined light curtain 5 is:

[0062]

[0063] Among them, t0 is the triggering moment when the flying projectile passes through the first detection light curtain 3 in the double rectangular ring photoacoustic detection combination light curtain 5.

[0064] Step 4: Calculate the angle β between the shock wave and the detection light curtain based on the ambient sound velocity x- , β x+ , β y- , β y+ And the half shock angle α of the projectile:

[0065] The angle β between the shock wave and the detection light curtain x- , β x+ , β y- , β y+ The calculation formula is

[0066]

[0067] Among them, c0 is the speed at which the shock wave propagates forward along the shock wave surface, that is, the ambient sound speed.

[0068] The calculation formula of the projectile's half shock wave angle α is:

[0069]

[0070] The same applies to the y direction.

[0071] Step 5, calculating the pitch angle θ and azimuth angle γ of the flying projectile passing through the double rectangular ring photoacoustic detection combined light curtain 5;

[0072] The calculation formula of the pitch angle θ and azimuth angle γ of the flying projectile passing through the double rectangular ring photoacoustic detection combined light curtain 5 is:

[0073]

[0074] Among them, γ2 is the pitch projection angle;

[0075] tanθ=cosγtanγ2(6

[0076] Step 6: Calculate the velocity component of the flying projectile in the z direction by combining the first detection light curtain 3 and the second detection light curtain 6, and solve the velocity vector of the flying projectile according to the pitch angle θ and azimuth angle γ calculated in step 5:

[0077] The calculation formula for calculating the velocity component of the flying projectile in the z direction at the triggering moment when the flying projectile passes through the first detection light curtain 3 and the second detection light curtain 6 is:

[0078]

[0079] Among them, t0 is the triggering moment when the flying projectile passes through the first detection light curtain 3, and t'0 is the triggering moment when the flying projectile passes through the second detection light curtain 6;

[0080] The velocity vector v of a flying projectile is calculated as

[0081]

[0082] In particular, when the projectile is vertically incident on the photoacoustic detection combined light curtain projectile velocity and target coordinate measurement device, steps 4 and 5 are unnecessary to measure, and there is no need to introduce the ambient sound velocity c0, and the velocity measurement formula of step 6 is simplified to

[0083]

[0084] See also Figure 4The second specific structure of the rectangular ring photoacoustic detection device 4 is as follows: four linear laser emitters 1 are divided into two groups and symmetrically distributed on the diagonals of the rectangle, two linear laser emitters are perpendicularly distributed at one corner of the rectangle, and another group of linear laser emitters are distributed at corresponding positions on the diagonal corner; four photodetectors 2 are arranged in the form of four linear laser emitters 1, but each group of photodetectors 2 and each group of linear laser emitters 1 are orthogonally arranged at the four corners of the rectangle.

[0085] The embodiments described above are only preferred specific implementation modes of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. A device for measuring projectile velocity and target coordinates by combining photoacoustic detection and light curtain, characterized in that: It comprises a double rectangular ring photoacoustic detection combined light curtain (5) and a second detection light curtain (6) which are parallel to each other and have a spacing of H, and collects a projectile passing through the curtain signal and a shock wave signal thereof; The double rectangular ring photoacoustic detection combined light curtain (5) comprises a first detection light curtain (3) in the same plane and two rectangular ring photoacoustic detection devices (4) arranged at a distance S outside the first detection light curtain (3), wherein the inner rectangular ring photoacoustic detection device (4) is arranged at a position that coincides with the edge of the rectangular detection light curtain; The rectangular ring photoacoustic detection device (4) is composed of four linear photoacoustic detectors, which are composed of a linear laser emitter (1) and a photoelectric detector (2) with a spacing L, and the four linear photoacoustic detectors form the four sides of a rectangle.

2. The device for measuring projectile velocity and target coordinates by combining photoacoustic detection and light curtain according to claim 1, characterized in that: The specific structure of the rectangular ring photoacoustic detection device (4) is as follows: four linear laser emitters (1) are distributed at the four corners of the rectangle, and adjacent linear laser emitters (1) are arranged perpendicular to each other in space; four photodetectors (2) are distributed at the four corners of the rectangle, and adjacent photodetectors (2) are arranged perpendicular to each other in space; the linear laser emitters (1) and photodetectors (2) arranged on the same side form a linear photoacoustic detector with a spacing L, and the four groups of linear laser emitters (1) and photodetectors (2) at the four corners of the rectangle form a rectangular ring photoacoustic detection device (4).

3. The device for measuring projectile velocity and target coordinates by combining photoacoustic detection and light curtain according to claim 1 is characterized in that: The specific structure of the rectangular ring photoacoustic detection device (4) is as follows: four linear laser emitters (1) are divided into two groups and symmetrically distributed on the diagonals of the rectangle, two linear laser emitters are perpendicularly distributed at one corner of the rectangle, and another group of linear laser emitters are distributed at corresponding positions on the diagonal corner; four photoelectric detectors (2) are arranged in the form of four linear laser emitters (1), and each group of photoelectric detectors (2) and each group of linear laser emitters (1) are orthogonally arranged at the four corners of the rectangle.

4. The method for measuring the velocity and target coordinates of a projectile by combining photoacoustic detection and light curtain according to claim 1 is characterized in that: The following steps are involved: Step 1: The projectile passes through the first detection light curtain (3) of the double rectangular ring photoacoustic detection combined light curtain (5), generating a trigger signal, and the two rectangular ring photoacoustic detection devices (4) begin to collect the shock wave signal of the projectile; Step 2: Calculate the apparent velocity component v of the shock wave in the double rectangular ring photoacoustic detection combined light curtain (5) according to the arrival time of the shock wave at the two rectangular ring photoacoustic detection devices (4). x+ 、v x- 、v y+ 、v y- ; Step 3, solving the coordinates (x, y) of the flying projectile in the double rectangular ring photoacoustic detection combined light curtain (5); Step 4: Calculate the angle β between the shock wave and the double rectangular ring photoacoustic detection combined light curtain (5) in combination with the ambient sound velocity x- , β x+ , β y- , β y+ and the half shock angle α of the projectile; Step 5, calculating the pitch angle θ and azimuth angle γ of the flying projectile passing through the double rectangular ring photoacoustic detection combined light curtain (5); Step 6: The projectile passes through the first detection light curtain (3) and the second detection light curtain (4). Combined with the triggering moments of the two, the velocity component of the flying projectile in the z direction is calculated, and the velocity vector of the flying projectile is solved according to the pitch angle θ and azimuth angle γ calculated in step 5.

5. The method for measuring the velocity and target coordinates of a projectile by combining photoacoustic detection and light curtain according to claim 4 is characterized in that: In the second step, the apparent velocity component v x+ 、v x- 、v y+ 、v y- The calculation formula is Wherein, S is the spacing distance between the inner rectangular ring photoacoustic detection device (4) and the outer rectangular ring photoacoustic detection device (4); v x+ 、v x- 、v y+ 、v y- are the propagation velocity components of the shock wave in the positive x-axis, negative x-axis, positive y-axis, and negative y-axis directions, respectively; t a1 ,t a2 are the arrival times of the shock wave at the left inner linear photoacoustic detector and the left outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain (5), respectively; t c1 ,t c2 are the arrival times of the shock wave at the right inner linear photoacoustic detector and the right outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain (5), respectively; t b1 ,t b2 are the arrival times of the shock wave at the lower inner linear photoacoustic detector and the lower outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain (5), respectively; t d1 ,t d2 They are respectively the arrival times of the shock wave reaching the upper inner linear photoacoustic detector and the upper outer linear photoacoustic detector of the double rectangular ring photoacoustic detection combined light curtain (5).

6. The method for measuring the velocity and target coordinates of a projectile by combining photoacoustic detection and light curtain according to claim 5, characterized in that: In the third step, the coordinates (x, y) of the flying projectile in the double rectangular ring photoacoustic detection combined light curtain (5) are calculated by: Here, t0 is the triggering moment when the flying projectile passes through the first detection light curtain (3).

7. The method for measuring the velocity and target coordinates of a projectile by combining photoacoustic detection and light curtain according to claim 6, characterized in that: In the fourth step, the angle β between the shock wave and the detection light curtain x- , β x+ , β y- , β y+ The calculation formula is Among them, c0 is the speed of the shock wave propagating forward along the shock wave surface, that is, the ambient sound speed The calculation formula of the projectile's half shock wave angle α is:

8. The method for measuring the velocity and target coordinates of a projectile by combining photoacoustic detection and light curtain according to claim 7, characterized in that: In the fifth step, the calculation formulas for the pitch angle θ and the azimuth angle γ of the flying projectile passing through the double rectangular ring photoacoustic detection combined light curtain (5) are: Among them, γ2 is the pitch projection angle; tanθ=cosγtanγ2 (6).

9. The method for measuring the velocity and target coordinates of a projectile by combining photoacoustic detection and light curtain according to claim 8, characterized in that: In the sixth step, the first detection light curtain (3) and the second detection light curtain (6) calculate the velocity component of the flying projectile in the z direction using the following calculation formula: Wherein, t'0 is the triggering moment when the flying projectile passes through the second detection light curtain (6); The velocity vector v of a flying projectile is calculated as

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