RU2231738C2 - Method for determination of exterior ballistic characteristics of flight of bullets and projectiles - Google Patents

Abstract

FIELD: for check-up and training in sighting.

SUBSTANCE: the time moments of passage of acoustic wave front through acoustic transducers installed on the target (at least six transducers) are registered, and the characteristics by a regression or mathematical model of the target are computer. The number of the transducers is selected according to the minimum quantity of the unknown data in the regression ore mathematical model, which are the beginning of the time count, corresponding to the moment of flight-by of bullet or projectile through the target plane, velocity of bullet or projectile, slope angles of their trajectory and the wind force value and wind direction. For determination of the position of the transducers identification of the position of the transducers identification of the model is performed, to this end, a reference frame is installed on the target, and a train of shots is performed on it. After each shot the time of operation of the transducers and the co-ordinates of rupture holes in the reference frame are measured, and then the co-ordinates of the transducers are determined by the method of least squares.

EFFECT: enhanced precision of measurements of co-ordinates and velocity of bullets and projectiles.

7 dwg

Description

The invention relates to targets for determining the external ballistic characteristics of the flight of bullets and shells and can be used in the experimental determination of accuracy and accuracy of fire and bringing weapons to normal combat, in determining speed.

Known electronic-acoustic target [1], containing a square or rectangular plate with acoustic sensors located at the centers of each of its sides, with which the moments of time of arrival of the sound wave from the point of impact of the bullet on the plate to the location of the acoustic sensors are recorded.

Known shooting range [2], in which to register the coordinates of the bullets contains the target panel, made in the form of a bulletproof screen with built-in acoustic sensors that record the time of arrival of the sound wave to the sensors from the place of its occurrence - the point where the bullet hit the screen.

The disadvantages of the electron-acoustic target and the shooting range are the small size of the registration field, in particular, due to primitive algorithms for determining coordinates based on the assumption of a small registration field, wear and tear of a plate or a bulletproof screen over time and the inability to register projectile coordinates for these reasons.

The closest analogue is a device for determining the external ballistic characteristics of the flight of bullets and shells [3], containing four acoustic sensors located on one straight line. Unlike previous devices, this device does not contain a plate or a bulletproof screen and therefore is applicable for determining the coordinates of not only bullets, but also shells.

The disadvantage of this device is the low accuracy due to the influence of the wind when using the device in an open area. Therefore, it is possible to work only in calm, calm weather, which is extremely rare. In addition, it is impossible to ensure high accuracy even in calm, calm weather on a large recording field due to the large error of the goniometric basic method of indirect measurements, when the directions of the rays passing from the sensors to the point of contact with the imaginary registration plane are far from normal (perpendicular) with respect to to each other.

To reduce the error of the goniometric basic method of indirect measurements, it is possible to arrange the sensors not in a straight line, but similarly to device (2) and increase the number of sensors by placing them, for example, on the sides of the target. Moreover, their location must be specified (measured) with an accuracy several times higher than the accuracy of measuring external ballistic characteristics. However, in the case of a large target field and the location of the sensors at a great distance from each other (up to 4-6 m on opposite sides of the target), it is not possible to set or measure the coordinates of the sensors directly with high accuracy (up to fractions of mm).

The objective of the invention is to eliminate the disadvantages of the device for determining the extrinsic ballistic characteristics of the flight of bullets and shells by creating a method for determining the extrinsic ballistic characteristics of the flight of bullets and shells, including fixing the time moments of the passage of the sound wave front through acoustic sensors mounted on the target in an amount not less than the number of unknowns in the regression or mathematical model (the origin of the time, corresponding to the moment of flight of a bullet or projectile through a plane target, bullet or projectile speed, the slope of their trajectory and the magnitude and direction of the wind), and calculating the coordinates of the flight of bullets or shells through the plane of the target using a regression or mathematical model, in order to determine the position of the sensors, model identification is carried out, for which previously the target sets the control frame and makes a series of shots at different points, and for each shot, the response time of the sensors and the coordinates of the holes in the control frame are measured, and then lyayut position sensors, for example, by the method of least squares when the number of the equations exceeds the number of unknowns.

The technical result is to increase the accuracy of measuring coordinates and speed, increasing the size of the registration field and the ability to work in open areas in the presence of wind.

вектор ветра

и его разложение в базисе X_TYZ, где ось Х_T совпадает с вектором скорости

ось Y вертикальна, а ось Z лежит в горизонтальной плоскости. Ось Х - продольная ось (по направлению стрельбы). На фиг.4 изображено сечение конуса звуковой волны плоскостью мишени, а на фиг.5 - сечение конуса звуковой волны плоскостью, проходящей через ось конуса, и нормальной плоскости мишени YZ. Фиг.6 иллюстрирует направление главных осей эллипса, фиг.7 иллюстрирует получение модели с учетом ветра и наклона траектории.Figure 1 shows a diagram of a device for determining the external ballistic characteristics of the flight of bullets and shells. Figure 2 shows a spatial arrangement of 12 acoustic sensors. Figure 3 shows the velocity vector of a bullet or projectile

wind vector

and its expansion in the basis of X _T YZ, where the axis X _T coincides with the velocity vector

the Y axis is vertical, and the Z axis lies in the horizontal plane. X axis - the longitudinal axis (in the direction of fire). Figure 4 shows a cross section of a cone of a sound wave by the plane of the target, and figure 5 is a section of a cone of a sound wave by a plane passing through the axis of the cone and the normal plane of the target YZ. Fig.6 illustrates the direction of the main axes of the ellipse, Fig.7 illustrates the receipt of the model taking into account the wind and the inclination of the trajectory.

The device (figure 1) contains acoustic sensors D _i , i = 1 ... 6, located in one plane three to the left and right of the sheaf of trajectories (figure 2), coaxial communication lines 1, block matching and threshold devices 2, a calculator 3, a monitor for displaying the results 4, and a control frame 5 with a target for identifying the regression model. In the case of accurate measurement of speed, six more sensors D _i , i = 7 ... 12, located similarly to the previous sensors, but in a different plane parallel to the target plane (FIG. 2), are introduced into the circuit of FIG. 1.

разложен по направлению полета пули или снаряда (ось X_T) и по вертикальной Х и горизонтальной Z осям системы координат мишени (фиг.3). Продольная составляющая

приводит к изменению положения центра возмущения атмосферы пулей или снарядом вдоль траектории и соответственно к изменению угла конуса Маха. Составляющие

приводят к поперечному сносу конуса Маха. В сечении конуса плоскостью мишени образуется эллипс (фиг.4, 5). Полуоси эллипса а, b и смещение центра эллипса ε определяются из геометрических соображений согласно фиг.3-6 следующими выражениямиWind speed vector

decomposed in the direction of flight of the bullet or projectile (X _T axis) and along the vertical X and horizontal Z axes of the target coordinate system (figure 3). Longitudinal component

leads to a change in the position of the center of atmospheric perturbation by a bullet or projectile along the trajectory and, accordingly, to a change in the angle of the Mach cone. Components

lead to lateral drift of the Mach cone. An ellipse is formed in the cross section of the cone by the target plane (Figs. 4, 5). The axes of the ellipse a, b and the displacement of the center of the ellipse ε are determined from geometric considerations according to Fig.3-6 by the following expressions

- число Маха, с - скорость звука.Where

- Mach number, s - speed of sound.

не превышает величины 0.99998 и, следовательно, эллипс практически является окружностью, радиус R которой пропорционален времени τ , т.е. R=V_kτ , где V_k - скорость распространения фронта волны в плоскости мишени. Согласно (2) смещение ε также пропорционально времени τ , так как L=Vτ . Суммируя векторы

получим результирующий вектор

направленный под углом ψ , как показано на фиг.7. Эвклидово расстояние между точками попадания (y,z) и датчика (y∂ ,z∂ ) равноThe components U _Y and U _Z lead to a parallel transfer of the center of the perturbation and, accordingly, of the entire ellipse along the Y, Z axes to distances proportional to the time τ = tt ₀ , i.e. on U _Y τ and U _Z τ, where t ₀ is the origin of the time (the moment the bullet flies through the target plane). For an angle α ≤ 0.1 rad. semi-axis ratio of an ellipse

does not exceed 0.99998 and, therefore, the ellipse is practically a circle whose radius R is proportional to time τ, i.e. R = V _k τ, where V _k is the propagation velocity of the wave front in the target plane. According to (2), the displacement ε is also proportional to the time τ, since L = Vτ. Summing up the vectors

we get the resulting vector

directed at an angle ψ, as shown in Fig.7. The Euclidean distance between the hit points (y, z) and the sensor (y∂, z∂) is

From Δ ABO we have

whence, taking into account (4), the model of the acoustic target follows

Here, the angle at the vertex O of the ABO triangle corresponds to the difference of the angles ϑ and ψ in Fig. 7, with 0 ≤ β ≤ π. therefore

The angle ϑ is determined by the position of the sensor (y∂, z∂) relative to the point of impact (y, z) and is equal to

Where

и проблемы деления на нуль в (8) и (9) не возникает. В противном случае надо проверять выполнение условия

и поступать соответствующим образом (принимать при условии

где δ - малая положительная величина).If the sensors are located to the left and right of the registration field, then

and the problem of division by zero in (8) and (9) does not arise. Otherwise, you must check the condition

and act accordingly (accept subject to

where δ is a small positive value).

Thus, in model (6) there are 6 unknowns V _k , U _p , ψ, t ₀ , y, z, and to determine them, at least 6 equations are needed, i.e. accordingly, 6 acoustic sensors with known coordinates y _i , z _{i of the} position of the sensors in space.

In the case of 12 sensors located in two planes at a distance D (Fig. 2), the variables V _k , U _p , ψ are the same and the system of equations contains 9 unknowns V _k , U _p , ψ, t ₀₁ , y ₁ , z ₁ , t ₀₂ , y ₂ , z ₂ with 12 equations that can be solved by the least squares method. For certain t ₀₂ , t _{01 the} horizontal velocity of the bullet or projectile is calculated

An acoustic target is essentially an indirect measurement system in which, according to primary measurements, i.e. by the time of the meeting of the sound wave with acoustic sensors, the inverse problem of external ballistics is solved, i.e. according to the model (equations) coordinates and speed are calculated. In order to calculate the coordinates with a given accuracy, it is necessary to set or measure the coordinates y∂ _i , z∂ _{i of the} position of the acoustic sensors relative to the target coordinate system with less errors. This is practically impossible, especially since the time moments of the passage of the sound wave front through the sensor are recorded at the time moments when the threshold device exceeds the threshold level signals. Therefore, the only means is the identification of a physical or regression model based on the results of a series of shots, when the times t _i are recorded for each shot by the system and the coordinates of the holes in the target are measured on the control frame 5 (Fig. 1), which is set only for identification, and during operation there is no acoustic target in the mode of determining coordinates and speed (removed). Since the position parameters - the coordinates of the sensors are many, then a large number of shots is required to identify the physical model (6). Moreover, for each shot, V _k , U _p , ψ, t ₀ will also be included in the number of unknowns. Therefore, the following approach is used. In the case of using in the model (6) the values of z∂ _i , z∂ _i , known to within the accuracy of their direct measurement, when calculating the coordinates of the point of impact y, z, errors arise that change little when measuring the external ballistic parameters of the bullet or projectile (tilt angles trajectory, speed), as well as wind. Therefore, a regression model is used for corrections, for example, in the form of a complete polynomial of degree 2

Each equation contains 6 unknown coefficients and it is necessary to fire at least 6 shots, or, for example, 9 shots at the corners, the center of the target and at the "star" points, i.e. along the coordinate axes at the borders of the target. When identifying y, z in equations (11), the coordinates determined using the model (6) for the measured coordinates of the sensors, Δ y = y ₀ -y, Δ z = z ₀ -z, where y ₀ , z ₀ are measured by the holes in the target are the coordinates of the points of impact. In the process of functioning in the operating mode, the coordinates of the points of contact are determined in 3 stages. First, y, z are determined by model (6), and then Δ y, Δ z corrections are determined by model (11), and finally,

A device for determining the external ballistic characteristics of the flight of bullets and shells works as follows. In the identification mode, behind the second plane with sensors (in the case of 12 sensors in two planes) or behind the plane of the sensors (in the case of 6 sensors in one plane), a control frame 5 with graph paper glued to it is installed. After the shot, the front of the sound wave of the Mach cone sequentially (in an order that depends on the coordinates of almost hit) crosses the acoustic sensors and electrical signals are generated at their outputs, which are transmitted through coaxial communication lines 1 to the input of the matching unit and threshold devices 2. From the output of block 2, the signals enter the interrupt bus of the calculator 3. The interrupt signals the state of the timer of the calculator (computer) and the time and sensor codes to which the time codes correspond are recorded in the computer's memory. After a series of shots are fired at the given points of the control frame 5, or after each shot, the coordinates of the holes are measured (and marked to avoid confusion) and entered into the calculator. After a given number of shots according to the program, for example, by the least squares method, models are identified (11). In this case, the sum of the squared residuals and residuals for each shot is calculated to control. Shots with large residuals are rejected and fired or shot, or defective points simply exclude and repeat the determination of model coefficients.

In the operating mode (operating mode), the equipment operates similarly to the identification mode. After a shot and recording in the memory of the calculator of the moments of time when the front of the sound wave intersects the sensors, the preliminary coordinates y, z are found using the program (6), then the program according to the model (11) with the coefficients a _i , b _i found during identification determines the corrections Δ y, Δ z and, finally, according to (12), the coordinates of the point of impact are refined. If necessary, the coordinates of each hole or the middle point of impact, dispersion characteristics (mean deviations, circles R ₅₀ , R ₈₀ , R ₁₀₀ , dispersion diameter) are displayed on monitor 4. In the case of 12 sensors, the horizontal velocity of the bullet or projectile is determined by (10).

The proposed device has a large registration field (up to 2 × 3 m ² ), high accuracy in measuring the coordinates and flight speed of bullets and shells, provides high accuracy in open areas in the presence of wind.

Sources of information

1. Zakharov V.A. Electron-acoustic target. M .: Radio, 1975, No. 5, p.13-15.

2. Shooting range. Application No. 94043628, 1996, F 41 J 5/056. Applicants: Zakharov V.N., Romashkin V.V., Rublev N.N., Smirnov N.I.

3. A device for determining the external ballistic characteristics of the flight of bullets and shells. Application No. 93015148/23 of 1993.03.23, F 41 J 5/04. Date of publication of the claims 1995.09.20. Author Vyukov N.N. (prototype).

Claims (1)

A method for determining the extrinsic ballistic flight characteristics of bullets and shells, including fixing the time moments of the passage of the sound wave front through acoustic sensors mounted on the target in an amount of at least six, and calculating the characteristics using a regression or mathematical model of the target using a computer, characterized in that the number of sensors is selected by the minimum number of unknowns in the regression or mathematical model, which are the origin of the time, corresponding to the moment of flight pu and or the projectile through the target plane, the velocity of the bullet or projectile, the angles of inclination of their trajectory and the magnitude and direction of the wind force, while to determine the position of the sensors, model identification is carried out, for which a control frame is first installed on the target and a series of shots are made at specified points after each shot, the response time of the sensors and the coordinates of the holes in the control frame are measured, and then the coordinates of the sensors are determined by the least squares method.

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