RU2386100C1 - Optoelectronic device for registration of moment of bullet crossing light screen of target - Google Patents

Abstract

FIELD: weapon and ammunition. ^ SUBSTANCE: device comprises radiator with units of power supply and optoelectronic converter with photodetector and photocurrent amplifier. Converter is equipped with photodiode, amplifier-filter, threshold device for reduction of measurement error as a result of nutation, generator of output signal into communication line with target and circuit of moment detection, when centre of bullet gravity crosses the screen. Photodiode is matched by spectral characteristics with radiator with thin flat ends-current contact jaws. Circuit for detection of moment of time, when bullet centre of gravity crosses the screen comprises quartz generator of pulses, trigger, circuit "AND", counter, digital comparator, central processor device and inverter. ^ EFFECT: reduction of radiator energy intensity, improved evenness of brightness along its length and reduced pulsation of light flow. ^ 6 dwg

Description

The device relates to the field of determining external ballistic parameters (coordinates, initial speed, casting angle, ballistic coefficient, speed at a given firing range) and can be used as a blocking device consisting of targets and ballistic traces.

Known blocking devices in the form of wire target frames, solenoidal locks and optical gratings [1. Ventzel D.A., Shapiro N.M. External ballistics. P1. - M .: Oborongiz, 1939. - 210 p .; 2. Konovalov A. A., Nikolaev Yu. V. External ballistics. - Izhevsk: Publ. IPM UB RAS, 2003. - 191 p.]. The target wire frame contains a frame on which a wire is wound with a small pitch (not exceeding the diameter of the bullet). When flying, a bullet breaks the wire, which leads to an open circuit and the formation of an electrical signal. Disadvantages of the target wire frame: the wire is not always broken (if the bullet flies in the middle between adjacent turns and the step is not very small); low accuracy of recording the time of flight (the wire breaks when flying a certain distance with a certain tension of the wire) and the influence (small) on the further trajectory of the bullet.

The solenoid is a thin coil of large diameter (up to 1 m) through which current is passed. When a bullet flies inside the coil due to electromagnetic phenomena, the current value changes, which is recorded as the instant of time a bullet flies through a blocking plane. Disadvantages of solenoid blocking: low accuracy due to the small size and low slope of the electrical signal; small dimensions and the possibility of damage to the solenoid when installing at long range.

The optical lattice contains a line of illuminators (incandescent bulbs) with lenses forming directional beams of light, and photodetectors with lenses mounted against them at a distance. When flying, a bullet shields one of the light beams (or part of it), which leads to the appearance of an electrical signal at the moment the bullet crosses the beam. Disadvantages of the optical grating: relatively small registration field; the proximity of the lines of illuminators and photodetectors to a sheaf of trajectory and the possibility of damage in case of accidental contact; relatively low accuracy, since in the case of a bullet crossing the middle of the beam, the signal amplitude is greater and it reaches the threshold earlier than when the bullet spans between adjacent beams with their partial overlap; low reliability due to the large number of light bulbs and photodetectors.

The closest analogue is the light screens used in the light target [3. Afanasyev V.A., Afanasyeva N.Yu., Korotaev V.N. Sources of radiation for light screens. Bulletin of IzhSTU: period. scientific-theor. journal IzhSTU. - 2007. - No. 3 (35). - Izhevsk: Ed. IzhSTU. - S. 51-59; 4. The light target. RF patent No. 2213320 dated 09/27/2003 by application No. 2002116940 dated 06/24/2002, class. F41J 5/02, G01S 5/18. VNIIGPE / Authors Afanasyeva N.Yu., Verkienko Yu.V., Kazakov VS, Korobeinikov VV (prototype)], containing linear extended light sources (emitters) and optoelectronic converters (sensors). The working body of the emitter is a chromium tape with a section of 2 × 0.4 mm ² passed through an opening in the guides with a step of 30 mm and heated to a temperature of 1100 ° C by the flowing current. The disadvantages of the emitter are: variable brightness along the length due to cooling in places of contact with the guides; low light output due to inconsistency of the spectral characteristics of the emitter and the sensor photodiode; as a result, a large energy intensity (power up to 1.5 kW of a radiator 1.2 m long), non-linearity of the radiator due to bending of the tape between the guides during expansion due to heating by the flowing current. The error in registering the instant of time when the bullet crosses the light shield arises additionally because of the nutation angle of the bullet, since the intersection time is fixed at the leading edge of the signal, and not at the moment the screen is crossed by the center of gravity of the bullet. This error is especially significant in the case of tilted light screens used in the target.

The objective of the invention is to reduce the energy intensity of the emitter, increasing its straightness and uniformity of the brightness of the radiation along the length, ensuring the constancy of the width of the light screen at any distance from the sensor, determining the time when the screen crosses the center of gravity of the bullet.

The problem is solved in that in the known optical-electronic device for recording the moment of crossing the bullet of the target’s light screen containing an emitter with power supplies and mounted on the other side of the sheaf of bullet paths, an optoelectronic converter with a photodetector and a photocurrent amplifier, is equipped with an optical-electronic converter a photodiode, an amplifier-filter, a threshold device to reduce the measurement error due to nutation, a shaper of the output signal in the communication line with the target and the OCR circuit the time of crossing the center of gravity of the bullet of the light shield when the photodiode is matched by spectral characteristics with the emitter with thin flat ends-conductors made of closely joined tube lamps with an inner matte coating, in the centers of which high-temperature wires are located, knives are installed in front of the lamps, the total the length of which forms a diaphragm of constant width over the entire length of the emitter, equal to the width of the diaphragm of the optoelectronic converter, each the tube lamp is powered from a separate stabilized source of constant voltage with a small ripple voltage coefficient of the rectified voltage, and the circuit for determining the time when the center of gravity of the bullet of the light screen intersects contains a quartz pulse generator, a trigger, an "I" circuit, a counter, a digital comparator, a central processing unit and an inverter. The technical result is a reduction in energy intensity (from 1.5 kW to 60 W per lamp), increasing the uniformity of brightness along the length of the emitter, increasing straightness, matching the spectral characteristics of the emitter and diode of the sensor, low ripple of the lamp supply voltage and a large amplitude of the useful signal. All this, combined with the recording of the instant of crossing the screen by the center of gravity of the bullet, provides an increase in the accuracy of targets and ballistic traces.

Figure 1 shows a diagram of an optoelectronic locking device (light screen); figure 2 is a diagram of the conversion of an optical signal into an electric one; figure 3 is a functional diagram for determining the time point of the intersection of the center of gravity of the bullet of the light screen; figure 4 - electrical signals at the output of the amplifier-filter (photocurrent) 10 and u _k (t) at the output of the threshold device (comparator) 11; 5 - design diagram for explaining the definition of the intersection points in time the center of gravity of light on the screen bullet instants t _n t _k inputs and outputs thereof; Fig.6 is a diagram explaining the definition of the formation of the output signal of the light screen relative to t _k .

The device contains a linear extended light source (emitter) 1 with closely aligned tube lamps 2 with an internal scattering coating and a filament fixed in the center of the lamp with special supporting wire supports inside the housing 3 with a narrow slotted diaphragm. The lamps are powered separately from sources 4 of a stabilizing DC voltage with a low ripple of the rectified voltage. Opposite the emitter on the other side of the sheaf of paths in the dash, an optoelectronic transducer (sensor) 5 is installed, consisting of a housing 6 with a narrow slotted aperture, the width of which is equal to the width of the aperture of the emitter 1, with a cylindrical lens 7, a photodiode 8 set to 0.6 ... 1 of the focal length from the lens 7, with the board 9 of the filter amplifier (photocurrent) 10, the threshold device (comparator) 11, the circuit 12 for determining the time moment of the intersection of the center of gravity of the bullet of the light screen 21 and the shaper of the output signal 13. Scheme 12 contains vartsevy pulse generator 14, a trigger 15, circuit "I" 16, counter 17, digital comparator 18, a central processing unit 19 and the inverter 20.

The mathematical essence of determining the moment of time when the center of gravity crosses the bullet of the light screen is as follows. Denote the length of the bullet by l = l ₁ + l ₂ , where l ₁ is the distance from the head to the center of gravity (CT in Fig. 5), and l ₂ is from the CT to the bottom. Figure 6 shows the projection of the bullet onto a plane passing through the axis of the bullet and perpendicular to the light screen 15 at the moment of crossing the CT of the light screen. The amount of movement of the bullet from the moment the intersection begins to the moment the center of gravity crosses is x ₁ , and from this moment to the time x ₂ leaves the screen.

Given the constancy of the speed x = vt (v is the speed) and the duration of the intersection

τ = t _k -t _n (t _n and t _k are the time of the beginning of the intersection and the end of the intersection) we have

.Where

.

Those. the time the center of gravity crosses the screen does not depend on the angle of inclination of the screen α and on the angle of nutation of the bullet β, but to determine it it is necessary to measure t _n and t _k .

Given the reduced screen width h, equal to the duration of the signal at the output of the amplifier-filter 10, determined by the duration of its weight function, we have

where the correction factor is

The determination of t _c by (3) takes time. Therefore, we will generate an output signal t _ox with a fixed delay from t _c equal to Δ _c , i.e.

and calculate the necessary delay Δ _k from time t _k . According to Fig.6 we have

where from

Thus, the signal t _o must be delayed relative to the signal t _k by Δ _k according to (7), which will correspond to a constant delay by Δ _{c of the} signal t _c .

Therefore, the device provides a measurement of the moment the center of gravity crosses the bullet of the light screen.

The device operates as follows.

Preliminarily, in the central computing device (SRI) 19, a correction factor k is set, the delay time Δ _c, and before firing, trigger 15, counter 17 and SRI 19 are set to the initial (zero) state by the signal "Reset". After the shot, the bullet crosses the light screen 15, and at the output of the threshold device 11, a signal u _to (t) is generated, the leading edge of which corresponds to the time moment t _{n of the} beginning, and the trailing edge to the time point t _{to the} end of the intersection (Fig. 4). The signal t _n trigger 15 is set to a single state and through the matching circuit 16, the signals from the output of the clock 14 are fed to the input of the counter (St 2) 17, and from its output to the inputs of the digital comparator 18 and the central computing device 19. At the time the end of the signal u _to (t) at the output of the inverter 20, a signal t _to is generated, according to which the SRI 19 fixes the state of the counter 17 at this point in time (i.e., the time τ _to ) and calculates the τ _output from (7) and sets the code at the output τ _o , which is fed to the input of the digital comparator. In the comparator, upon receipt of the status code of counter 17 at the input A, the codes are compared and, at the moment of their coincidence, the signal for transmission to the coaxial communication line with the device (target, ballistic path) is received at the input of the shaper 13, the light screen of which is used .

The proposed optoelectronic blocking device (light screen) provides a reduction in energy intensity (from 1.5 kW to 60 W per lamp), increased uniformity of radiation along the length, low noise due to low ripple of the lamp supply voltage, large amplitude of the useful signal due to high output the emitter and matching the spectral characteristics of the emitter and the diode of the sensor. All this, combined with recording the time when the center of gravity of the bullet crosses the light screen, reduces the error in registering the time the bullet enters and leaves the light screen and the error due to the angle of nutation of the bullet.

Claims (1)

An optical-electronic device for detecting the moment when a bullet crosses a target’s light screen, which contains an emitter with power supplies and is mounted opposite to the sheaf of bullet paths opposite to a sheaf of bullet paths; - a filter, a threshold device to reduce the measurement error due to nutation, an output signal shaper into the communication line with the target, and a moment determination circuit and the time of crossing the center of gravity of the bullet of the light shield, while the photodiode is matched in spectral characteristics with the emitter with thin flat ends-current leads made of closely joined tube lamps with an inner matte coating, in the centers of which high-temperature wires are located, knives are installed in front of the lamps, the total length which provides a diaphragm of constant width over the entire length of the emitter, equal to the width of the diaphragm of the optoelectronic transducer, each tubular amp is fed from a separate stabilized DC voltage with a small ripple of the rectified voltage coefficient, and the circuit determining the time points of intersection of the center of gravity of the light screen comprises bullets quartz pulse generator trigger circuit "I", the counter, the digital comparator, a central processing unit and the inverter.

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