RU2451302C1 - Simulator of glare re-reflections of laser light by sea surface - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: in the device, the second input of the glare X-coordinate generator is connected to the output of a clock pulse generator, and its output is connected to the first input of a personal computer having a display. N frequency tunable high-frequency generators are connected respectively to the second inputs of mixers in a block of mixers through N-2 controlled electronic switches of heterodyning signals. The control inputs of the N frequency tunable high-frequency generators are connected to outputs of N control voltage generators, the inputs of which are connected to outputs of an N-channel random number generator, each having dimension n, which is synchronised by signals from the clock pulse generator, where n is the number of rows in the matrix of glare re-reflections of the equivalent zone of the sea surface. The output of the clock pulse generator is also connected to the second input of the computer and the input of the N-channel random number sensor, each having dimension m, where m is the number of columns of said matrix, the output of said sensor being connected to the glare Y-coordinate generator, the output of which is connected to the third input of the computer. The output of the clock pulse generator is connected to the random number sensor with dimension N-2, the output of which controls the number generator switched by the controlled electronic switches of the N-2 frequency tunable high-frequency generators, and N-2 outputs of that number generator are connected to N-2 controlled electronic switches through electronic drives.

EFFECT: possibility of checking operation of the radioelectronic channel of a laser coherent locator designed to detect and auto-track sea-based low-altitude missiles.

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Description

The invention relates to instrumentation and can be used as a simulator of pulsed high-frequency signals generated at the output of a matrix photodetector with a dimension mn - elements in a matrix that receives laser radiation, reflected by glare of the sea surface, randomly distributed in time and space, when solving a location problem for low-flying sea-based missiles (m is the number of columns, n is the number of rows in the matrix).

A known method of laser ranging low-flying sea-based missiles (type "Harpoon"), based on the sounding of a diffraction limited object moving above the surface of the sea (ocean), unmodulated emissions of a single-frequency continuous laser and multichannel coherent processing of received radiation by a matrix photodetector with the determination of Doppler frequency shifts in the reflected radiation and subsequent multichannel parallel matched filtering of the selected radio signal c, characterized in that the radiation reflected from several glare of the sea surface, incident on the photodetector matrix from different randomly distributed angular directions, is additionally and simultaneously subjected to coherent reception and processing, and Doppler frequency shifts in the received radiation are determined in the corresponding channels associated with the photodetector array from glare of the sea surface and the corresponding angular coordinates to these sea glare, calculate the current coordinates of the location of the object and its true speed, as well as statistically average the results of calculations of the entire set of joint measurements of these parameters [1].

There is also known a different method of laser location of such missiles, in which the scattered radiation signals from the missile are not used in the direction of its sounding due to coatings masking the missile, which reduce its effective scattering surface, and the missile is detected and auto-guided by moving patches of light with the rocket moving re-reflections of laser radiation by glare of the sea surface, above which there is a moving rocket, scattering the probe radiation of the locator in the direction of the locale ovannuyu sea surface [2].

Analogues of the claimed technical solution is not available.

The aim of the invention is to provide the ability to verify the operation of the electronic path of a laser coherent locator designed to detect, auto-track along angular coordinates and measure the parameters of a low-flying sea-based rocket - its radial speed and slant range - and containing a mn-element matrix photodetector in the receiving channel that senses glare reflections of laser radiation scattered by a rocket into a localized zone of the sea surface.

This objective of the invention is achieved in a simulator of glare of laser radiation by the sea surface, including a series-connected clock generator, a linear frequency-modulated signal generator, a block of N parallel-working mixers, an adder of linear-frequency-modulated signal equivalents, a matching amplifier, a dispersion delay line loss-compensating broadband amplifier, amplitude detector, threshold device, broadband amplifier and driver X- glare coordinate, the second input of which is connected to the output of the clock generator, and the output is connected to the first information input of a personal computer with a display, as well as N frequency-tunable high-frequency generators connected respectively to the second inputs of the mixers in the mixer block via N-2 controlled electronic switches heterodyning signals, the control inputs of N frequency-tunable high-frequency generators are connected to the outputs of N control voltage conditioners (or Dov), the inputs of which are connected to the outputs of an N - channel random number sensor of dimension n each, synchronized by the signals of the clock generator, where n is the number of rows of the matrix of flare rereflections of the equivalent zone of the sea surface, the output of the clock generator is also connected to the second input of a personal computer with a display and to the input of the N-channel random number sensor of dimension m, where m is the number of columns of the matrix of glare reflections of the equivalent zone of the sea surface, the output of this sensor is connected to to the Y-coordinate flare corrector, the output of which is connected to the third information input of a personal computer with a display, in addition, the output of the clock generator is connected to a random number sensor of size N - 2, the output of which controls the number former of frequency-tunable controlled electronic switches N - 2 switched by high-frequency generators, and N - 2 outputs of this shaper are connected to N - 2 controlled electronic switches through the corresponding electronic drives.

The achievement of the objective of the invention is explained by the formation at the output of the threshold device of a series of ultrashort pulses randomly distributed over time, displaying the X-coordinates of the glare, the number of which randomly varies in the range from 2 to N in each formation cycle, in which the corresponding randomly distributed Y-coordinates of the glare are also formed, which allows programmatically in a personal computer with a display for preset values of the radial velocity of the proposed rocket, its altitude above sea level, the initial the apparent range of the alleged missile and the coordinates of the laser coherent locator to determine the flight dynamics of the proposed missile in time with the calculation of the dynamics of changes in its angular coordinates - azimuth and elevation angle, using the technique of statistical averaging of the XY coordinates of glare in the sequence of their formation cycles to determine the true current coordinates of the proposed missile. The simulator allows you to replace full-scale tests of a laser coherent radar with a real flying rocket at the stage of designing the structure of the locator, which is dictated by economic feasibility.

The block diagram of the simulator is shown in Figs. 1 and 2 and contains:

1 - clock generator (GSI),

2 - generator linear frequency-modulated signals (HLFM),

3 - block of parallel running N mixers,

And ... N - N - 2 managed electronic switches,

4 - adder linearly-frequency-modulated signal equivalents,

5 - matching amplifier,

6 - dispersion delay line (DLZ),

7 - loss-compensating broadband amplifier,

8 - amplitude detector,

9 - threshold device

10 - broadband amplifier,

G-01 ... G-10 - frequency-tunable high-frequency generators (their number N),

11 ... 20 - shapers control voltages (their number N),

21 - N-channel random number sensor of dimension n for each,

22 - N-channel random number sensor of dimension m,

23 - shaper Y-coordinates of the glare,

24 - random number sensor of dimension N - 2,

25 - shaper of the number of switched on controlled electronic switches (from A to H) N - 2 frequency-tunable high-frequency generators G-03 ... G-10,

26 ... 33 - electronic drives (their number N - 2) of switches A ... H,

34 - shaper X-coordinates of glare,

35 - personal computer with a display (with installed processing program).

Figures 3 and 4 show rocket 36 flying at a speed of V at a height h above the sea surface and a laser coherent locator 37 mounted on a ship at a distance L from the rocket.

Figure 5 shows a block diagram of a laser coherent locator, which contains:

38 - a single-frequency gas laser of a continuous transmission channel, for example, a powerful CO ₂ laser with a radiation frequency ν _O (with a wavelength of 10.6 μm),

39 - the first beam splitting cube (with low reflection and high transmittance),

40 and 41 - reflectors of the transmitting channel,

42 - transmitting telescope,

43 - receiving lens

44 is a matrix photodetector with a matrix of dimension mn elements, for example, based on the connection "cadmium-mercury-tellurium", cooled by liquid nitrogen,

45 is a single-frequency gas laser of the heterodyne channel, for example, a CO ₂ laser tuned to a frequency ν _HET ,

46 - piezoelectric corrector tuning the frequency of the laser radiation 45,

47 - a moving mirror of the laser cavity 45,

48 - the second beam-splitting cube, similar to cube 39,

49 and 51 are reflectors of the heterodyne channel,

50 - photometric wedge (to adjust the power of the local oscillator channel),

52 - forming optics of the heterodyne channel,

53 - reflector heterodyne channel,

54 - the third beam-splitting cube with 50% transmittance and reflection,

55 - photosystem mixer automatic frequency control (AFC) heterodyne laser 45,

56 - mixer RF channel system AFC,

57 - the local oscillator of the AFC system,

58 is a resonant filter tuned to the frequency ν _ГЕТ -ν _O + F _O ,

59 - phase-sensitive rectifier (PCV),

60 - reference generator for the operation of the PCF, tuned to the frequency + F _O ,

61 - integrator AFC system,

62 - DC amplifier,

63 is a block of data processing of the receiving channel, including DLZ processing,

64 - a personal computer with a display (with the entered processing program),

65 - calculator of the angular coordinates of the target,

66 - azimuth control drive β,

67 - control angle elevation ε,

68 is a curve of the Doppler gain loop for CO ₂ lasers 38 and 45.

Consider the action of the claimed device.

The clock generator 1 generates short pulses that determine the period T of the cycle of operation of the device. These pulses with a delay ΔT start the LFM generator 2 high-frequency impulse signals of duration t _IMP = T-ΔT (ΔT delay is carried out inside the HFM circuit, for example, using a single-shot circuit). At the output of GLFM 2, a periodic sequence of radio pulses with linear frequency modulation in the range Δf = f _MAX -f _{MIN is formed} , where f _MAX is the maximum tuning frequency, f _MIN is the minimum. The LFM signals are fed in parallel to the first inputs of the mixers of unit N of the mixers 3, the second inputs of which receive high-frequency signals from the outputs of N frequency-tunable high-frequency generators G-01 ... G-10. At the same time, two of these generators are constantly connected to the respective mixers, and the remaining N - 2 through N - 2 controlled electronic switches A ... H. In each of these generators, the oscillation frequency during the delay time ΔT is set within the band ΔF, that is, from the minimum frequency f _{C MIN} to the maximum frequency f _{C MAX} , so that f _{C MAX} -f _{C MIN} = ΔF. At the output of each of the mixers of block 3, the following pulsed LFM equivalent signals are generated periodically with total frequencies f _LFM-E (t) = f _LFM (t) + f _C (t), where f _MIN ≤f _LFM (t) ≤f _MAX and f _{C MIN} ≤f _C (t) ≤f _{C MAX} are the ranges of possible changes in the LFM signal in GLFM 2 and the oscillation frequencies in the G-01 ... G-10 generators (fixed frequencies within this cycle). The number of heterodyning signals arriving at the mixer unit 3 can vary in different cycles from two to N (in the device N = 10 indicated in Fig. 1), depending on how many controlled electronic switches A ... H are turned on using electronic drives 26 ... 33.

The composite signal of the LFM equivalents, the number of which is K (where 2≤K≤N) in the considered cycle, after amplification in the matching amplifier 5, is fed to the input of the dispersion delay line (DLZ) 6, consistent with the K signals of the LFM equivalents. The matching factor means the equality ΔF _LZ / τ _LZ = Δf / t _IMP , where ΔF _LZ and τ _LZ are the bandwidth and duration of the impulse response of the DLZ 6. Note that the product ΔF _LZ τ _LZ = B >> 1 is the base of the DLZ, and the value (B) ^1/2 determines the magnitude of the increase in the signal-to-noise ratio at the output of the DLZ, which significantly increases the detection ability of location devices using complex radio signals (LFM) with their matched filtering based on the DLZ.

The duration of the “compressed” radio pulses t _SJ at the output of DLZ 6, as is known, is equal to t _SJ = 1 / ΔF _LZ , and their temporal position relative to the front of the pulses of the clock generator 1, respectively, t ₁ , t ₂ , t ₃ , ... t _K is determined by the frequency values the heterodyning signals f _C1 , f _C2 , f _C3 ... f _CK from the output K of the active frequency-tunable high-frequency generators G-01 ... G-10, where K≤N. "Compressed" radio pulses are located in the time interval Δt _SJ = t _IMP- τ _LZ . Therefore, the maximum number of “compressed” radio pulses resolved from each other is equal to R = τ _LZ Δf or R = B Δf / ΔF _LZ , that is, it is possible to separately receive and process a large number of LFM equivalents or, what is the same, a significant increase in the number N, since usually R >> N.

After the passage of “compressed” radio pulses in the compensating loss of a broadband amplifier 7 with a passband ΔF _LZ and their detection in an amplitude detector 8 K pulse signals are subjected to threshold restriction in a threshold device 9 with a set threshold that cuts noise emissions (interference), and amplification in a broadband amplifier 10, and its output signal arrives at the X-coordinate shaper of the flare 34, for an explanation of the action of which we turn to the consideration of Figs. 3 and 4. So, Fig. 3 shows the radiation from the radial at the current velocity V of rocket 36 along the X axis. The irradiation frequency is ν _O. This radiation is scattered by the rocket in various directions by the rocket body on the sea surface to a certain site. The size of this site is determined by the scattering surface of the rocket and can be significant. However, the size of such a surface on the sea surface under a flying rocket, visible by the matrix photodetector of a laser coherent locator, is a limited number of mn elements in the photodetector matrix, where m is the number of columns and n is the number of rows in the matrix.

It is known from the theory of the Doppler effect [3-4] that the frequency of a scattered moving radiation rocket is determined by the formula ν _PAC = 2ν _O V cos α / c, where α is the angle between the velocity vector V and the direction of scattered radiation, s = 3 · 10 ⁸ m / s - electrodynamic constant (speed of light in vacuum). Therefore, the frequency of scattered radiation ν _PAC can be both higher and lower than the frequency of irradiation ν _O with a laser coherent locator, depending on the scattering angle α. If the size D of the illuminated zone of the sea surface (see Fig. 3) along the X axis corresponds to the elevation angle of view of the photosensitive matrix with n rows, then the range of the missile scattering angles visible by the locator lies in the range from α ₁ to α ₂ for a given value of the inclined range L ( fig. 4). Correspondingly, the frequencies of the scattered radiation in the indicated range of angles α lie in the range ν ₂ ≤ν _O ≤ν ₁ and the angle α ₂ = π-α ₁ , and the frequency of the radiation scattered by the rocket at an angle π / 2 is equal to the radiation frequency of the rocket ν _O.

It is easy to understand that the sea surface always experiences some kind of excitement (from calm to storm) and therefore can be interpreted as a combination of quasi-point reflectors randomly distributed on it by laser radiation scattered by a rocket. Such a surface is a spatial modulator of flare rereflections distributed spatially stochastically in time. Such flashing reflections of laser radiation act in the laser coherent locator (Fig. 5) on the corresponding elements of the photodetector array 44 with dimension mn. Moreover, on m elements of the kth row of the matrix, where k = 1, 2, 3, ... n, the frequency of the radiation scattered by the rocket ν _k (α) is the same (along the Y coordinate) and is determined by the scattering angle α.

The stochasticism of the time-spatial distribution of glare of laser light reflections by the sea surface is simulated in the inventive device using three sensors 21, 22 and 24 (Fig. 2) of random numbers triggered by pulses from a clock generator 1. Using an N-channel sensor 21 random numbers of dimension n for each in each operation cycle, the devices are set by control voltage generators 11 ... 20 (their number is also N) randomly distributed in the Δf range frequencies of generated oscillations in tunable by hour totem of high-frequency generators G-01 ... G-10. Using an N-channel sensor 22 of random numbers of dimension m, N random coordinates Y are set for all flare re-reflections with X coordinates, that is, the N-channel sensor 22 generates N random code combinations in parallel, each of which is mapped to a coordinate in the Y-coordinate shaper of glare 23 X generated in the X-coordinate shaper of the glare 34. And the obtained groups of X and Y coordinates of the glare re-reflections are transmitted to a personal computer with a display of 35. Finally, with the help of a sensor 24 random numbers of dimension N - 2 in each during the operation of the device, a specific number of effective glare is set, the number of which in the cycle can vary from two to N. This is achieved by the operation of the shaper associated with this sensor 25 of the number included by controlled electronic switches (from A to H) N - 2 frequency-tunable high-frequency generators G- 03 ... G-10. Electronic switches are switched on using electronic drives 26 ... 33.

Information on the clocking of the operation cycles of a device operating according to the corresponding data processing program for glare coordinates and their number is achieved by connecting the clock generator 1 with a personal computer with a display 35. The distribution of simulated glares in a series of successive cycles is statistically processed, as a result of which the current coordinates of the scattering laser are found radiation from an alleged moving rocket. Setting the parameters of the radial velocity V of the rocket, its initial slant range L and the flight altitude h above sea level, the computer calculates the current coordinates of the rocket and the angular coordinates on it - azimuth β and elevation angle ε.

The operation of the simulator is similar to the action of a laser coherent locator when operating on a real low-flying sea-based missile. The structure of such a locator is depicted in Fig. 5 and previously described by the author in different versions [5-11]. The locator uses a powerful single frequency CO ₂ laser 38 and the continuous low power LO CO ₂ continuous laser 45 to emit frequency tuning ν _GET> ν _O by changing the length of the resonator pezokorrektorom 45 mounted thereon reflector cavity 47, as can be seen on the curve of the Doppler gain loop 68. Using a frequency-locked loop, the frequency difference ν _HET -ν _{O is} maintained with the required accuracy [12]. The frequencies of the glare reflections from the sea surface received in the receiving channel by the photodetector matrix 44 are mixed with the frequency of the optical local oscillator, and the difference signal of the difference frequency of the coherent photo mixing is transmitted to the data processing unit 63 of the receiving channel, the structure of which is similar to that presented in the inventive simulator (Fig. 1) using DLZ 6.

Consider an example of the implementation of a laser coherent locator made according to the scheme in Fig. 5. Let the photodetector matrix have a dimension of 100 × 100 elements, i.e. m = n = 100. The frequencies of the received glare laser radiation ν (α) lie in the range ν _O −Δν * ≤ν (α) ≤ν _O + Δν *, where Δν * = 1.414 V ν _O / s = 40 MHz, provided that V = 300 m / s, ν _O - 2.83 · 10 ¹³ Hz, 45 ° ≤α≤135 °, D = 2h and ν _ГЕТ = ν _O +120 MHz. If we use a line with a passband ΔF _LZ = 40 MHz and a duration of the impulse response τ _LZ = 50 μs (base of the DLZ V = 2000) as the DLZ, then the tuning band in the HFDM is 2 Δf = 80 MHz with the duration of the LFM pulse t _IMP = 100 ms at T = 1 ms. Then the difference frequency of flare reflections and the frequency of the laser local oscillator 45 at the output of the photodetector 44 will lie in the range from 80 MHz to 160 MHz. A higher difference frequency will correspond to the largest scattering angles α ₂ (Fig. 3), and the smallest to the minimum angles α ₁ . The frequency of 120 MHz corresponds to the central (50th) element of the photodetector matrix or to that line of the sea surface above which the rocket is located.

Thus, the location of a potential adversary’s rocket can be judged by the position of the center of the flare rereflection of the laser radiation scattered by the missile after statistical processing in a personal computer with a display of 64 flare groups for several consecutive processing cycles, followed with a frequency of 1 / T. This will also make it possible to find the angular coordinates of the rocket sensing line — azimuth β and elevation angle ε — in the calculator of angular coordinates of target 65 and to conduct auto tracking of the target with control drives 66 and 67 in azimuth and elevation, respectively.

Information sources

1. Smaller O.F. Location method. RF patent No. 2296350, publ. in the bull. No 9 on 03/27/2007.

2. Smaller O.F. A method for detecting low-flying sea-based cruise missiles. Application for invention No. 2009148918/28 (072324) with priority dated 12/28/2009 (substantive examination is conducted from 03/09/2010).

3. Landsberg G.S. Optics, 5th ed., M., 1976.

4. Frankfurt U.I., Frank A.M. Optics of moving bodies, M., 1972.

5. Smaller O.F. Laser Doppler Locator. RF patent №1829641, priority from 03.25.1991.

6. Smaller O.F. Monopulse radio signal detector. RF patent No. 2046370, publ. in the bull. No. 29 dated 10/20/1995.

7. Smaller O.F. Pulse Detector. RF patent No. 2310882, publ. in the bull. No 32 on 11/20/2007.

8. Smaller O.F. Laser Doppler Locator. RF patent No. 2335785, publ. in the bull. No. 28 dated 10/10/2008.

9. Smaller O.F. Laser coherent locator. RF patent No. 2352958, publ. in the bull. No. 11 of 04/20/2009.

10. Smaller O.F. The method of laser heterodyne reception of radiation. RF patent No. 2349930, publ. in the bull. No.8 of March 20, 2009.

11. Smaller O.F. A method of processing information in a laser coherent locator with a matrix photodetector. RF patent No. 2354994, publ. in the bull. No 13 on 05/10/09.

12. Smaller O.F. Device for auto-tuning the frequency of a laser Doppler locator. Author's certificate. USSR No. 1591675 with priority from 08.24.1988.

Claims (1)

A simulator of glare of reflections of laser radiation by the sea surface, including a series-connected clock generator, a linear-frequency-modulated signal generator, a block of N parallel-working mixers, a linear-frequency-modulated equivalent signal adder, a matching amplifier, a dispersion delay line, compensating for losses of a broadband amplifier , amplitude detector, threshold device, broadband amplifier and X-coordinate flare driver, the second input of which is connected an with the output of the clock generator, and the output is connected to the first information input of a personal computer with a display, as well as N frequency-tunable high-frequency generators connected respectively to the second inputs of the mixers in the mixer block through N-2 controlled electronic switches of the heterodyning signals, control inputs N Frequency tunable high-frequency generators are connected to the outputs of N shapers of control voltages (or codes), the inputs of which are connected to the outputs of N-k random numerical sensor of dimension n each, synchronized by the signals of the clock generator, where n is the number of rows of the matrix of flare reflections of the equivalent zone of the sea surface, the output of the clock generator is also connected to the second input of a personal computer with a display and to the input of the N-channel random number sensor of dimension m, where m is the number of columns of the matrix of glare rereflections of the equivalent zone of the sea surface, the output of this sensor is connected to the shaper Y-coordinates of the glare, the output of which connected to the third information input of a personal computer with a display, and the output of the clock generator is connected to a random number sensor of size N-2, the output of which controls the shaper of the number of high-frequency generators tuned by controlled electronic switches N-2, and the N-2 outputs of this shaper connected to N-2 controlled electronic switches via corresponding electronic drives.

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