RU2601284C1 - Method for adaptive spectral selection of targets - Google Patents

Abstract

FIELD: rocket construction.

SUBSTANCE: invention relates to spin-stabilized guided missiles, projectiles and combat elements with passive infrared homing on air, ground surface and other targets. Proposed is a method for adaptive spectral selection of targets basing on spectral dividing of perceptible by the homing head optical radiation into three channels, conversion of optical signals of each channel into electrical signals, double differentiation of the electric signals, adaptive binary signal quantization, comparing the obtained binary signals on voltages comparators considering weight coefficients, and identifying the pulses as belonging to the target, a false optical target or a passive background interference with subsequent extraction of signals from the target basing on the criterion of minimizing false alarms.

EFFECT: technical result is the increase of background interference protection level and higher efficiency of selection in a complex and variable target background interference environment, in particular when using by the enemy low-temperature and combined false optical targets.

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Description

The present invention relates to the field of rotating guided missiles, shells and military elements (EB) with passive infrared (IR) homing on airborne (CC), ground targets (SC) and other objects of military equipment and weapons that emit in the optical wavelength range. The invention relates to means of noise suppression from passive emitters and organized optical counteraction (OOP), for example, false optical targets (LOC) of various classes for the objects indicated above with infrared homing (OS).

Designing rotationally stabilized OSs equipped with optical homing heads is a daunting task. OGS of such OS contains several interdependent systems of automatic regulation and control (SAUR) with direct, feedback and cross-links. For example, an optical-electronic tracking coordinator (OESK), an electric locking system (SEA), an optical-electronic tracking system (OESC), an acceleration device and a stabilization system for the angular velocity of rotation of the gyroscope OESK, a homing system (OESS + autopilot) and, if necessary scanning system.

External influences and disturbances for such OSs are all sources of optical radiation (IOI) that are in the field of view of the OGS. These can be IOIs from objects intended for destruction (CC, SCs and other targets), and IOIs from all other objects that are not intended to be hit, from passive interference, from VOCs of various types, from sky backgrounds or the underlying surface of the earth. Backgrounds can also be of a different nature: long, colorful, with different brightness, radiation energy and contrast, as a rule, their nature depends on the time of day and weather. CCs and SCs also differ in the type, character, and composition of the spectrum of their OI. Specific combinations of all the combat use listed in the real situation are called interference-targeting conditions or ensembles.

All these IOIs, and most importantly the CC and SC, can change their sizes and shapes, from point in the far zone to dimensional in the middle and to cover the field of vision of the GHS in the near zone. In this case, the brightness and energy of the OI of the CC and SC can vary from a threshold value of 1.5 · 10 ^-16 W / cm ² to values exceeding it by 10 ³ ÷ 10 ⁵ times. And most importantly, the LOCs are constantly being improved and are gradually approaching in the spectrum of their radiation to the spectrum of the CC and SC.

All of the above circumstances should be taken into account when developing an OGS and a spectral target selector (SSC), which is very difficult and difficult to do, and in many cases it is completely impossible to fully take into account due to the a priori uncertainty of the interference-targeting situation that can arise in real combat use.

Now briefly consider the well-known OOP methods from the CC and SC and the known types of LOCs. Known OOP techniques [1, 2, 3] are based on dumping, shooting, towing or dispersing the LOC, or blinding OGS photodetectors with powerful OI (magnesium guns, cesium lamps or lasers). High-temperature LOCs are based on the combustion of pyrotechnic compositions of fuels (Al, Mg), oxidizing agents, cementers, phlegmatizers and chemical additives that control the burning rate, or pyromorphic substances. Low-temperature and combined LOCs contain pyrotechnic compositions and elements heated by them.

Now we give specific examples of the difficulties and complexities of the tasks of the SSS.

1. The main IOI of the CC is a nozzle of a turboprop or turbojet engine (TVD, turbojet engine) and a jet torch of the hot products of combustion of aviation kerosene (for airplanes), or a hot exhaust of a gas turbine engine (helicopters). Thus, the type of the OI spectrum, the form of its spectral (frequency) functional dependence and its maximum are determined mainly by the type of engines; for airplanes, this can be a conventional turbojet turbojet, with fuel afterburning, or with a controlled thrust vector. In the latter case, the nozzle is completely open and the OI spectrum shifts to the middle wavelength region of IR radiation

2. Not only the brightness and energy of the OI, but also the spectrum change as the rocket approaches the target. For example, when using high-temperature LOCs (pyrotechnic tracers), the ratio of the OI levels of the near IR region to the visible from the VC and VOC as the rocket approaches the VC to 200-300 m varies from 0.2 ÷ 0.3 to 0.8 ÷ 0, 9. (Installed when setting up the SSC OGS "Needles" in natural conditions).

3. The spectrum of the RC OI varies depending on the angle of fire. For example, when launching a rocket “towards” the nozzle of the turbojet engine is completely, and the torch is partially shielded by the fuselage. During the start-up, both the nozzle of the aircraft and the jet torch are fully open, and on the side angles they can be partially screened.

4. The task of the SSC is also complicated by the uncertainty which type of LOC will be used if the pilot or CC equipment detects the launch of a rocket.

5. The task of selecting the NC is even more difficult, since the exhaust of a diesel engine or gas turbine engine of armored vehicles is more shielded compared to the CC, which reduces the thermal visibility of the target. And the backgrounds of the underlying surface are more colorful, and any burning on the ground will create interference that is close in spectrum to the SC.

In view of all of the above, we turn to the consideration of known methods of SSC.

The known method of SSC used in the OGS of a rotating anti-aircraft guided missile (IZUR) "Needle" [5]. The known method is based on the spectral separation of the OI perceived by the OGS using optical filters into two spectral channels: the main (OK) with a maximum sensitivity in the near infrared region, and the auxiliary (VK) with a maximum in the visible region of the spectrum, the conversion of optical signals OK and VK in electrical, one-time differentiation of the OK and VK signals, detecting the levels of OK and VK signals with amplitude (peak) detectors, comparing or calculating the relations of the obtained levels, and classifying the IOI as a CC if Uoк-Uвк> 0, and as LOC, if Uoк-Uвк≤0, the formation of "gates" of belonging to the VC and LOC, followed by rejection in the OK channel of pulses from the LOC. The known method allows you to efficiently select only high-temperature VOCs, and is ineffective when using low-temperature and combined VOCs.

The closest is the known method of SCS based on spectrodivision of optical spectral distribution into three channels (RF, VZUR 9M336 of the 9K333 Verba anti-aircraft complex), converting optical signals of three channels into electrical signals with one-time differentiation, detecting their levels, and comparing the levels of three spectral channels. The use of three channels gives richer possibilities for selecting not only high-temperature LOCs, but also low-temperature ones, but only in a favorable interference-targeting environment, since in the closest SSC, it is unlikely to use devices (adaptation) to a complex and changing environment and digital processing of DSP signals. Meanwhile, it’s almost impossible to design such devices as OGSs to the VZUR using calculations; in these cases, designing with the methods of simulation gives the best result.

Thus, the closest known method of SSC does not provide effective selection of various types of targets in a complex and changing interference-target setting. It was shown above [2] that the spectra of OIs of all AIs that can fall into the field of view of the OGS can vary depending on the types of targets, their angles, types of VOCs, time of day, weather, etc., that is, there is a lack of a priori information and the initial uncertainty of information about the expected situation. All these circumstances cannot be considered when designing. Without the introduction of adaptation (adaptability), it is impossible to establish in advance the optimal structure, parameters and selection algorithms even when using three-channel spectro-sharing. In each specific case of interference-targeting situation there will be information losses.

The aim of the invention is to increase the level of noise suppression of the OS with IR self-guidance and selection efficiency in a complex and changing interference-targeting environment.

This goal is achieved by the fact that in the method of spectral selection based on three-channel spectrodivision of OI, conversion of OI of each channel into electrical signals, amplification with simultaneous differentiation of the received signals, detection of their amplitudes, and classification of belonging to the target or LOC by comparing the obtained amplitude detection of voltages with additional correction according to the values of relations, the formation of "strobes" of the membership, followed by selection (selection of the signal from the target) and notch (deleted ) interfering signals from the LOC, characterized in that they double-differentiate the signals of each channel, adaptive binary quantization of the twice-differentiated signals, compare the obtained binary signals on voltage comparators, pre-setting the variable weight coefficients with hardware or software, and then determine the belonging to the target, LOC and interfering background noise by the analysis of the obtained logical variables X1, X2, X3 of the space of spectral features, alternately setting the key analysis functions for each specific interference-target ensemble, taking into account the highest separability measure, followed by self-training and correction of adaptive binary quantization thresholds and weight coefficients according to the criterion of minimizing false membership ratings (sometimes called "false alarms").

Introduced in the proposed method, the set of operations provides the claimed useful technical effect as follows. Firstly, by switching to DSP, which in turn provides the possibility of implementing adaptive selection using non-linear filtering of signals from targets, LOCs and backgrounds. Secondly, the introduction of a new operation of twofold differentiation of spectral channel signals reduces information loss in binary quantization (this will be explained later in the example of a device for implementing the proposed method), this operation is previously unknown. Thirdly, the introduced set of operations provides the possibility of choosing for analysis of spectral features with the greatest measure of separability, setting weight coefficients, and the use of weighting coefficients reduces the complexity of the algorithms (no need to calculate the stress ratio). And finally, the introduction of an adaptation controller gives flexibility, that is, by reprogramming it is possible to provide selection when new types of targets and LOC appear, without changing the hardware, which is impossible when using analog signal processing. Thus, the technical solution of the method has a novelty and meets the criteria of an inventive step. Its implementation does not require the use of unknown materials, mechanical, optical and electronic components, and the technology for manufacturing 3-channel OESKs is also known, which meets the criterion of industrial applicability.

In FIG. 1 is a timing chart of an analog portion of a signal processing illustrating the advantages of double differentiation; FIG. 2 is a functional diagram of a device for implementing the method with the addition of additional devices (signal simulator and evaluation unit), FIG. 3, 4 is an example of a self-study program of FIG. 2 devices.

In FIG. Figure 1 shows the signal "a" generated by pulse-width modulation of the aberration spot from a target or interference during the rotation of the modulating strip "g" with the angular velocity ω of rotation of the rotor of the gyro gyro coordinator gyroscope. Signal "a" has a bell-shaped shape (approximately for calculations it can be replaced by the elementary function sin ² ωt). Once a differentiated bipolar signal "b" crosses the zero level at the time of the extremum of the primary bell-shaped signal. The twice-differentiated signal “c” crosses the zero level at the edges of the aberration spot. From here we see that the use of the “in” signal for binary quantization gives undoubted advantages: quantization is simplified and a more accurate selection of information parameters of signals with pulse-width modulation is provided.

Presented in FIG. 2, the device contains a 3-channel OESK 1, an adaptive digital spectral target selector (SSC) 2 with an adaptation controller 3 with input and output modules 3-1, 3-2 installed in the launcher or on board the rocket (if flight adaptation is provided) as well as a simulator of 4 signals and a block 5 of selection estimates, that is, the number of false alarms. The signal simulator and the evaluation unit, together with the OESK and the SSC, are essentially a modeling complex for the physical modeling of specific interference and target ensembles, which is needed for the self-tuning of the SSC with subsequent additional verification of its functioning.

For OESK 1, only those elements are shown that have electrical and optical connections with SSC 2 and simulator 4. Photodetectors 1-1, 1-2, 1-3 and preliminary pulse amplifiers 1-4, 1-5, 1-6 s are shown single differentiation.

SSC2 contains differentiating devices 2-1 of the main channel (OK) and 2-2, 2-3 auxiliary spectral channels (VK1, VK2), adaptive binary quantizers 2-4, 2-5, 2-6, code-controlled dividers 2-7 , 2-8, 2-9 voltages, comparators 2-10, 2-11, 2-12, analyzers and shapers of "strobes" 2-13, 2-14, 2-15 of the signals belonging to the target, LOC and background.

For self-tuning of the SSC, first on the 4-signal simulator simulate reference interference-target ensembles, for example, they simulate helicopter OIs, resetting pyrotechnic tracers and extended low-light backgrounds, or aircraft OIs with turbojet engines, resetting low-temperature LOCs and dark night or day sky backgrounds, etc. Then, the data of the simulated ensemble is entered and the controller calculates the optimal parameters for it (see the example program in Figs. 3, 4), the settings of which are input from the output module to the SSC and set the weighting factors on the voltage dividers, preliminary upper and lower thresholds of binary quantization on quantizers 2-4, 2-5, 2-6 (see Fig. 2), and on the analyzers 2-13, 2-14, 2-15, the calculated switching functions. Further, the program makes a step-by-step adjustment of the CCC parameters according to the criterion of minimizing false estimates (alarms), the data on the number of which in each step comes from block 5 of the selection efficiency estimates. For this, algorithms that implement simple enumeration methods, and recursive least squares methods and others can be used. Variations of ensembles can also be set on the simulator, for example, simulating changes in the spectra of the optical spectra at different angles of the target, backgrounds, etc. After self-tuning, the optimized SSC parameters for each ensembles are recorded in the memory cells of the ROM of controller 3 in order to use them in a real situation of combat use. To simplify the structure of the SSC and signal processing algorithms, instead of calculating the relations of voltage levels, we express the ratios: Uок: Uвк1, Uок: Uвк1, and Uвк1: Uвк2, where UОк, Uвк1 and Uвк2 are signal levels of the main, first and second auxiliary channels that have maximums spectral sensitivity in the middle, near infrared and visible, respectively, in the form: Ui> α _to Uj and Uj <α _to Ui, where Ui, Uj are the values of the weighted signal levels of the compared zones of the spectral regions, and α _{k is the} corresponding weight coefficient of the relations of the weighted signal levels . This allows you to set weights on code-controlled voltage dividers.

After adjusting the SSC on the signal simulator, it is desirable to carry out additional adjustment and check the effectiveness of selection in natural conditions, since the simulators do not provide complete identity of the OI of real targets, LOCs and backgrounds.

In real conditions of combat use, the SSC works as follows. At the fire control target designation point, the targets are distributed and the arrow is informed of the type of its center, the expected angle of the target's approach and the type of LOC (he sees the background of the shooter himself). The shooter enters this data, and the controller extracts the optimal parameters for the ensemble from the corresponding ROM cell, enters these settings in the SSC, in which the optimal binary quantization thresholds, weighting factors, and switching functions of the analyzers are set. When the CC allocated to it enters the launch zone, the shooter performs aiming, capturing the target, transferring to tracking mode and launch.

The scope of the claims of this application is limited by the method, therefore, in accordance with the regulation, the application materials do not provide specific circuitry solutions, and examples of the specific implementation of the method and the program are shown enlarged in a framework sufficient to disclose the method and the principle of its functioning. For acquaintance with more open solutions of the adaptive binary quantizer, controlled voltage dividers, and how it is very simple to use the logic of the analyzer switching functions based on the use of 3 by 8 multiplexers, you should refer to the materials of the parallel application "Adaptive Digital Spectral Target Selector". As shown above, the present invention meets the criteria of inventive step and industrial applicability.

Information sources

1. A.V. Rozanov. Foreign Military Review: Aircraft Countermeasures for Infrared Homing Missiles, 1977.

2. Foreign Military Review, 2015, Means of dealing with electronic-optical equipment.

3. US patent No. 5030465, patent of the Russian Federation No. 2403531, patents of Belarus No. 7524, 16509.

4. A.A. Krasovsky and others. Fundamentals of the theory and design of guided single-channel rotating missiles, VVIA them. Zhukovsky, 1963.

5. Technical description of the product 9E410 (OGS "Needle"), technical description of MANPADS 9K38M ("Needle"). M., Oborongiz, 1980. - analogue.

6. VZUR 9M336 “Pussy-willow” (author's note: “Pussy-willow” has a signature stamp “c”, therefore the author used only data that is publicly available on the Internet). - prototype.

7. A.S. USSR No. 195839, 213317, 214409, 233041, 236968, 236947, 235948, 258598, 261198, 270481, 283003, 286187, 298492, 301547, 301265, 317301, 317759, 320963, 323213, 328661 and others.

Claims (1)

A method of adaptive spectral target selection, which consists in the spectral separation of optical radiation perceived by the homing head through the channels, pulse-width modulation of the spectrally separated optical radiation in each channel, the conversion in each channel of the optical signals into pulse-width-modulated electrical signals, amplification and differentiation of the obtained pulse-width modulated pulses, amplitude detection of pulse-width modulated pulses in each channel and comparison of the obtained amp levels lithod, characterized in that the spectral separation of the optical radiation perceived by the homing head is carried out in three channels, the second differentiation of the pulse-width modulated pulses in each channel is made, adaptive binary quantization of the PWM pulses in each channel is performed, they are compared on comparators, pre-setting them the corresponding weight coefficients , and the data obtained in this way are then analyzed step by step, classifying them according to the membership of the target, false optical target or pass implicit background noise, followed by isolation of the target signals according to the criterion of minimizing false alarms and spurious signals from removal purposes and passive optical background interference.

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