RU2516265C2 - Method of protecting radio communication object from radio-guided high-precision weapon and system for realising said method - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to military radio communication equipment and can be used to improve protection of mobile or stationary interacting radio objects from a radio-frequency radiation guided high-precision weapon (missile). The disclosed method involves emitting false signals which determine generation of the trajectory of the high-precision weapon which leads the weapon to a region which is safe for radio objects, for which a barrier zone for interacting radio objects is formed, where a high-precision weapon is captured and led in directions which are safe for the protected radio objects.

EFFECT: creating a virtual point of guiding a high-precision weapon (missile) further from the protected radio object at a distance greater than the effective striking radius of the payload of the high-precision weapon by changing supply of guidance energy to the homing head, which characterises the attacking radio-target of the high-precision weapon, so that its homing head is not able to maintain the direction towards the intended target, and rendering the guidance and control systems incapable of guiding the attacking missile to the target, which protects the radio object under attack.

6 cl, 12 dwg

Description

The invention relates to military radio communications equipment and can be used to increase the security of mobile or stationary interacting radio-emitting objects (RIO) from high-precision weapons (missiles) induced by radio emission (missiles), actively used in modern military operations.

General analysis of the problem. Achievements of technology after the Second World War allowed the creation of the WTO, the use of which has become an effective way to incapacitate both mobile and stationary RIOs. There is a group of WTOs that satisfy the “shot and forget” principle, which are guided by the RIO for most of the flight time by radio radiation from the RIO with sufficient radiation power. During the flight to the intended target, the WTO selects the best points in the energy sense of the detected radio emission. Information on radio emission arriving at the homing head entering into the WTO (GOS), on the basis of which the WTO control system directs it to the target, which determines the high probability of hitting the target. The GTS WTO is designed to work in any area or any areas of the energy spectrum, but the common thing is that all homing heads should receive energy to track the intended purpose. The energy receiver of the homing head is a thin, sensitive mechanism, always protected by placing it behind the fairing, which is transparent to energy of a given frequency.

The high probability of destruction and relatively low cost, especially in comparison with the potential target, make them cost-effective weapon systems, which determined the spread of the WTO. This has increased the danger posed by these weapons, both for warring and non-combatants, especially in the case of receipt of these ammunition by terrorist countries and / or organizations.

The defense strategy for countering the WTO is as diverse as the probable targets of these munitions. None of them is ideal, none works against any threat, and not one individually or in combination with others is capable of eliminating the WTO threat with high guarantee.

Known methods and devices for reducing the accuracy of pointing the WTO in the form of anti-radar missiles by reducing the amount of information coming from the protected RIO (radar) to the WTO (Nebabin V.G. et al. "Protecting the radar from anti-radar missiles." - "Foreign Radio Electronics" ", No. 5, 1990, p. 73). Examples of this approach are:

1. Methods based on the introduction of an additional device for detecting the WTO and false transmitters with antennas, and the protected RIO when the detection of the WTO is turned off, and the false transmitters turn on and emit signals in the direction of anti-radar missiles (German Patent No. 3341069, Japanese Application 2-40193). Reducing the operating time of the protected RIO on the air by completely or periodically turning off the protected RIO determines the increase in the error of pointing the WTO. The duration of the pause in the operation of the protected RIO is determined by the time of flight of the WTO of the final section of the trajectory, the value of which is determined by the required magnitude of the miss.

The disadvantage of these methods is, firstly, the necessity of detecting and recognizing the OBE, which is a difficult task due to the small area of the effective scattering surface of the OBE, and secondly, during the sequential start of several OBEs, the pause value may be unacceptably large. With this method of defense, the enemy achieves the goal of incapacitating the protected RIO from the system, if not by destroying it, then by forced shutdown.

2. Methods based on the termination of the radiation of the protected RIO towards the WTO when the latter is detected and the signal of a false source is emitted through an additional antenna connected to the RIO cable or directly from the reflector installed on the ground (German Patent No. 429509, British Patent No. 2252464) or in the air (Japanese Application No. 4-351984).

The disadvantage of these inventions is that the antennas are also easily affected by both high-explosive and fragmentation components of the warhead of the WTO when it is undermined even at a distance of two to three tens of meters, which leads to damage to the transceiver equipment that generates masking pulses.

A common drawback of the methods that use false transmitters emitting their signals through the antenna towards the WTO to protect RIOs is that when the energy of these signals is sufficient to protect the RIO, the WTO re-targets the false transmitter and hits it with a probability close to unity. Therefore, with a simultaneous attack on the RIO by several WTOs (the standard method of conducting combat operations is the “wolf pack”) after the first missile hits the false transmitter, subsequent missiles confidently hit the protected RIO.

Thus, a common drawback of the described methods is the insufficient effectiveness of the RIO protection from the WTO, which is a consequence of the high probability of the WTO defeating false transmitters and microwave cables connecting the protected RIO to the false transmitter.

Closest to the proposed invention is a method of protecting RIO in the form of a radar station (radar) from the WTO (anti-radar missile (RPR)) (RF patent No. 2170940, G01S 7/06, 2001), which consists in emitting false signals using a second RIO (false signal manager (PLC)), for which the coordinates of the PLC are measured, the measured coordinates are compared with the set and, if they differ by an amount greater than the threshold, control commands are generated that move the PLC to a given point or along given trajectories, and the trajectories andthe coordinates are set, based on the conditions for the formation of the PRR motion path leading to the area safe for the radar, and the coordinates of the PLC at known coordinates of the active jammer (PAP) or the PRP are selected, based on the condition for the PLC to be removed from the jammer (PRP), at a distance determined by the formula

, $$R_l\le R_R\sqrt{P_l{G}_l/P_R{G}_R}$$

,

where R _l , R _p - the distance from the PAP (PRR) to the PLC and radar, respectively; P _l , P _p - the power of false and working pulses, respectively; G _l , G _p - gain of the antenna PLC and radar, respectively, in the direction of the background radiation pattern of the antenna.

The disadvantage of this method is the low probability of suppressing a missile control signal and (or) control signals of several guided missiles in a group attack, because:

1) the emission of interfering pulses in the direction of the radiation source is a unmasking sign that allows the attacker to change the parameters of the missile control channel and thereby disrupt a possible counteraction;

2) in case of simultaneous attack on the RIO by several WTOs (the standard method of conducting combat operations is the “wolf pack”) after the first missile is hit by a false transmitter, subsequent missiles confidently hit the protected RIO;

3) the lack of consideration of the current interference situation in the space for countermeasures imposes significant requirements on the system for protecting an object from guided missiles to ensure the energy of interfering radiation.

The aim of the invention is to expand the capabilities of the prototype method, by increasing the security of RIO from the attacked WTO in a group attack.

The technical result of the present invention is to create a virtual point of guidance of the WTO (missiles), remote from the protected RIO at a distance exceeding the effective radius of destruction of the warhead of the WTO, by changing the supply of guidance energy to the GOS, characterizing the attacking radio target of the WTO, so that its GOS could no longer save direction to the intended target, and bringing as a result of this guidance and control system incapable of aiming the attacking missile at the target, i.e. the output of the received energy beyond the parameters of the homing head (threshold of its perception), which ensures the invulnerability of the attacked RIO.

$$\left(l=\frac{c\left(\Delta t_{в}-2\Delta t_0\right)}{2}\right)$$

, задают коэффициент кратности m=l/λ расстояния между РИО l и длины волны данного излучения λ и рассчитывают за время τ₀ частоту f излучения в режиме излучения ложных сигналовThe problem is solved in that the increased security of the RIO from damage to the WTO, in the proposed method, is achieved by forming a barrier zone of the interacting RIO, which allows the capture and removal of the WTO in the directions that are safe for the protected RIO, for which periodically remember the current parameters of the radio mode of the interacting RIO , stop their communication and switch to the measurement and synchronization mode, while forming a clock from the command to the slave RIO, take it as a slave RIO and relay RIO added to the command which it receives and in turn generates the slave RIO second clock, wherein the measured transfer time clock for each RIO Δt Δt _k and _in taking into account the processing time clock Δt ₀ RIO each calculated distance between them $$l=\frac{c\left(\Delta t_{\mathrm{to}}-2\Delta t_0\right)}{2}$$

$$\left(l=\frac{c\left(\Delta t_{\mathrm{at}}-2\Delta t_0\right)}{2}\right)$$

, Define the multiplicity factor m = l / λ distance l between RIO and given radiation wavelength λ and time τ is calculated for the frequency f ₀ of the radiation in the radiation mode spurious signals

f = mc / l,

, что обеспечивает возникновение стоячей волны между РИО и определяет режим когерентного кругового радиоизлучения, которое формирует интерференционное поле от взаимодействующих РИО, при этом по мере приближения ВТО к цели, осуществляя выбор наилучших в энергетическом смысле точек интерференционного поля радиоизлучения, оно переходит к центральной интерференционной полосе, выводящей ВТО на виртуальную цель, причем длина когерентности l_ког, определяющее глубину заградительную зону для эффективного захвата и увода ВТО по интерференционному полю радиоизлучения к виртуальной цели,Then they switch to the mode of emission of false signals in the form of a train of coherent circular radio emission with a coherence time Δt, for which they synchronize the radiation between the interacting RIOs by turning on the radiation of coherent circular radio emission for the slave RIO after calculating the radiation frequency f, and the delay in the beginning of the radiation of coherent circular radio emission from the command RIO is equal to $${\tau }_{\mathrm{to}}=\frac{\Delta t_{\mathrm{to}}}{2}$$

that ensures the occurrence of a standing wave between the RIO and determines the mode of coherent circular radio emission, which generates an interference field from the interacting RIO, while approaching the WTO to the target, choosing the best points in the energy sense of the interference field of the radio emission, it goes to the central interference band, bringing the WTO to the virtual target, and the coherence length l _coh , which determines the depth of the barrier zone for the effective capture and removal of the WTO by interference radio field to a virtual target,

l _coh = Δtc = 2πc / Δω≤R,

where R is the range of coherent circular radio emission

, $$R=\frac{c}{\mathrm{four}\pi f}\sqrt{\frac{P_{Pd}{\eta }_{\mathrm{one}}{G}_{\mathrm{one}}{\eta }_2{G}_2}{P_{G\mathrm{FROM}N0}}}$$

,

where P _GOS0 - signal power at the input of the GOS in free space; P _PD - transmitter power; η ₁ , η ₂ - efficiency of the transmitting and receiving feeder lines; G ₁ , G ₂ - antenna gain; f is the radiation frequency in the mode of coherent circular radio emission.

In addition, the zone into which the WTO is withdrawn is located between the protected RIOs, the length l of which for the WTO with the combat radius r _be with a safety margin δ of RIO protection is chosen equal to

l≥2r _be + δ,

and the virtual target in the zone is located in the middle between the protected RIOs. In this case, the safety factor δ of the RIO protection is determined by the range of the WTO due to its remaining energy resource after reaching the virtual target.

The power of the attacked transmitters P _PD in the circular radio emission mode is chosen so that in the coordinate of the virtual target the power of the resulting field exceeds the maximum permissible radiation value at the input of the GOS P _GOSmax , which leads to blindness and failure of the GOS, i.e.

. $$P_{Pd}\ge \frac{{\pi }^2{l}^2{P}_{G\mathrm{FROM}N\mathrm{<figure-callout\; id="2"\; label="max\; f"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">max\; </figure-callout>}}{f}^{}{}^2}{{\eta }_{\mathrm{one}}{G}_{\mathrm{one}}{\eta }_2{G}_2{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">c</figure-callout>}}^2}$$

.

Moreover, the transition from the communication mode of the interacting RIO to the radio emission mode is made with a period

, $$\Delta t\le \frac{\mathrm{one}}{2F_{\max }}$$

,

where F _max - the maximum frequency of the spectrum of the information message.

The system according to the proposed method consists of two identical devices, each of which contains a receiver, a transmitter, two pulse shapers, a clock shaper, three switch blocks, a time interval meter, a calculator, a generator, a control unit, a high-frequency amplifier, an antenna matching unit, an antenna , a delay element and a “Command-Slave” switch of operation modes, the output of the receiver being connected to the input of the first block of switches and through the first pulse shaper and the first switch the selector of operating modes with the first input of the control unit, the second input of which is connected through the second pulse shaper to the “Start” input of the device, the first output of the first switch block is connected to the “Output” output of the device, and its second output is connected to the first input of the clock generator and the meter input time intervals, the information outputs of the latter are connected to the first information inputs of the calculator, the second information inputs of which are connected to the inputs of the "Specification of the coefficient of multiplicity", and the output before the end of the measurement of the time interval meter with the control input of the calculator, the information outputs of which are connected to the inputs of the frequency generator, and the output of the end of the calculation of the calculator through the third contacts of the mode switch with the start input of the generator directly and through the delay element, the first output of the control unit is connected to the control input of the first block of switches and the second block of switches, and through the second contact of the mode switch with the second input of the shaper pulse train, the output of the latter is connected to the first information input of the second block of switches, the input “Input” of the device is connected to the second information input of which, and the output is to the input of the transmitter, the output of which is connected to the first information input of the third block of switches, the second information input of which is connected to the output of the generator , the control input with the second output of the control unit, and the output through the high-frequency amplifier and the matching unit with the antenna with the antenna, the second output of which is connected to the input of the receiver ka.

The analysis of the level of development of the technology made it possible to establish that there are no analogues that are characterized by a combination of features that are identical to all the features of the claimed technical solution, which indicates the compliance of the claimed invention with the patentability condition of "novelty". The inventive method meets the criterion of "inventive step", since the introduced distinguishing features are not found in the analogues, but requires justification.

The claimed method is illustrated by the spatial-geometric model of the method of protecting RIOs from the WTO in the form of guided missiles, shown in Fig. 1. The closed segment of the sphere; S _to X _to X _in S _in is the limiting part of the airspace in which the target is captured and the further flight path of the rocket is adjusted. The effective range of the GOS of most missiles, the carriers of which are combat helicopters, does not exceed 3 km, while the effective range of guided missiles is from 15 to 20 km [1]. Under the radio control, from the moment of its launch, a rocket flies from 12 to 17 km at a speed of 250-300 m / s. Thus, the system is protected RIO from guided missiles minimally only has 40-56 seconds to capture the WTO over the air and remove it from the RIO.

When pointing the WTO to the remote virtual radiation source, as provided by the present invention, the efficiency of protecting the RIO from the damage of the WTO is increased compared to known methods, since the virtual radiation source can be located at a distance of up to 100 meters from the RIO.

The system according to the proposed method of protecting RIOs from the WTO includes two identical devices (Fig. 2), each of which for example may contain a receiver Pr 1, a transmitter Prd 2, two pulse shapers FI ₁ 3 and FI ₂ 4, a pulse shaper FSI 5, three blocks switches BP ₁ 6, BP ₂ 7 and BP ₃ 8, time interval meter IVI 9, calculator 10, generator G 11, control unit BU 12, high-frequency amplifier UHF 13, matching unit with antenna BSaA 14, antenna 15, delay element 16 and the "Command-Slave" switch of operating modes 17.

In this device, the output of the receiver Pr 1 is connected to the input of the first block of switches BP ₁ 6 and through the first pulse shaper FI ₁ 3 and the first switch of operating modes 17 with the first input of the control unit BU 12, the second input of which is connected through the second pulse shaper FI ₂ 4 to input "start" device. The first output of the first block of switches BP ₁ 6 is connected to the output "Output" of the device, and its second output is connected to the first input of the FSI clock generator 5 and the input of the time interval meter 9. The information outputs of the time interval meter IVI 9 are connected to the first information inputs of the calculator Calcul. 10, the second information inputs of which are connected to the inputs of "Specifying the coefficient of multiplicity", and the output of the end of the measurement of the time interval meter IVI 9 with the control input of the calculator 10. Information outputs of the calculator Calcul. 10 are connected to the inputs of the frequency reference of the generator G 11, and the output of the end of the calculation of the calculator Calcul. 10 through the third contacts of the operating mode switch 17 with the "Start" input of the generator G 11 directly and through the delay element 16. The first output of the control unit BU 12 is connected to the control input of the first block of switches BP ₁ 6 and the second block of switches BP ₂ 7, and through the second contact of the operating mode switch 17 with the second input of the clock generator 5. The output of the clock generator 5 is connected to the first information input of the second block of switches PSU ₂ 7, to the second information input of which the input "B the device’s move, and the output to the transmitter input is FD 2. The output of the transmitter Fr 2 is connected to the first information input of the third block of switches BP ₃ 8, the second information input of which is connected to the output of the generator G 11, the control input with the second output of the control unit BU 12, and the output through the high-frequency amplifier UHF 13 and the matching unit with the antenna BSA 14 with the antenna 15. The second output of the matching unit with the antenna BSA 14 is connected to the input of the receiver Pr 1.

An example of the implementation of the control unit BU 12 is shown in figure 3, which contains the element OR 18, three elements And ₁ 19, And ₂ 20, And ₃ 21, three RS-flip-flops T ₁ 22, T ₂ 23, T ₃ 24, pulse generator GI 25, two shift registers PC ₁ 26 and PC ₂ 27.

Both inputs of the control unit 12 through an OR element 18 are connected to the first input of the first element And ₁ 19, to the second input of which is connected the inverse output of the first trigger Tp ₁ 22, S - the input of which is connected to the output of the first element And ₁ 19 and with S - the input of the second trigger T ₂ 23, the direct output of the first trigger T ₁ 22 is connected to the control input of the pulse generator ГИ 25. The output of the generator ГИ 25 is connected to the first input of the second And ₂ 20 and the third And ₃ 21. The output of the second trigger T ₂ 23 is connected to the second input of the second element And ₂ 20, the output of which is connected to the input of the first about the shift register RS ₁ 26. The output of the first shift register RS ₁ 26 is connected to its installation input in the initial state, with S the input of the third trigger T ₃ 24 and with R the input of the second trigger T ₂ 23. The output of the third trigger T ₃ 24 is connected with the second input of the third element And ₃ 21, the output of which is connected to the input of the second shift register PC ₂ 27. The output of the second shift register PC ₂ 27 is connected to its installation input in the initial state and to R - inputs of the first and third trigger (T ₁ and T ₃ ). The second outputs of the shift registers 26 and 27 are the outputs of the control unit 12.

The operation of the device in the proposed system of protection of the RIO from the radio-controlled WTO is reduced to cyclic switching from the radio mode to the synchronization and measurement mode and then to the radio emission mode (Fig. 4). The intervals of the radio exchange mode and the radio emission mode are determined by the discretization of the information message according to the Kotelnikov theorem, according to which a signal with a limited spectrum (F _max ) is completely determined by samples with a frequency

F _d ≥2F _max ,

where F _d is the sampling frequency, F _max is the maximum frequency of the signal spectrum.

So, for example, for a telephone channel, F _max is 3.4 kHz, i.e. The TLF signal can be transmitted in separate values, following with a frequency of 6.8 kHz and higher (the standard value of the sampling frequency in the 8 kHz TLF channel).

1. In the radio mode during the radio interval (figure 4) in an open space, a point emitter uniformly emits radio waves in all directions with a radiated power P _PD , and the power flux density at a distance R is evenly distributed over the surface of the sphere:

, $$P_{PR0}=\frac{P_{Pd}{\eta }_{\mathrm{one}}{G}_{\mathrm{one}}{\eta }_2{\mathrm{<figure-callout\; id="2"\; label="G"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">G</figure-callout>}}_2{\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}^2}{16{\pi }^2{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">R</figure-callout>}}^2}$$

,

where P _CR0 - signal power at the output of the receiver in free space; P _PD - transmitter power; η ₁ , η ₂ - efficiency of the transmitting and receiving feeder lines; G ₁ , G ₂ - antenna gain; λ is the wavelength of the working frequency range; R is the distance between the transmitter and the receiver.

In real space

P _ave = P ² V _pr0

where V = E / E ₀ is the attenuation factor; E is the electromagnetic field strength at the input of the receiver in real space; E ₀ - electromagnetic field strength at the input of the receiver in free space.

2. In the radio emission mode, a system consisting of two RIOs, during a time T _rad (Fig. 4), forms their barrier zone (Fig. 1), where the GTS of the WTO captures a signal from a false target, which creates an interference field from interacting RIOs and distorts the energy field of the protected RIO. When controlling the WTO from the GNS, the resulting effect of F _Σ0 affects the WTO, which translates the WTO into the central trajectories of interference maxima. As a result, the WTO moves to the center line of interference and redirects to the virtual target S ₀ , leaving the zone safe for RIO. Thus, a barrier zone is created for interacting RIOs that is optimal from the point of view of the emerging raid situation and that allows for the diversion and withdrawal of the WTO towards a virtual target that is safe for the protected RIO. The area into which the WTO is secured (if it does not destroy the WTO with fire weapons) should be located from the RIO at a distance greater than the range of the GOS of the WTO or the range that the WTO can cover due to the remaining energy resource. The apparatus (GS), which registers the effect of incoming waves at a point, measures the intensity of oscillations over a finite time interval Δt, i.e. time average squared amplitude

, $$〈A^2〉=\frac{\mathrm{one}}{\Delta t}{\displaystyle \underset{0}{\overset{\Delta t}{\int }}{A}^{2}dt=A_{\mathrm{one}}^2+A_2^2+2A_{\mathrm{one}}{\mathrm{<figure-callout\; id="2"\; label="A"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">A</figure-callout>}}_2〈\cos \Delta \varphi 〉=I_{\mathrm{one}}+I_2+2A_{\mathrm{one}}{\mathrm{<figure-callout\; id="2"\; label="A"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">A</figure-callout>}}_2〈\cos \Delta \varphi 〉=I}$$

,

where the bar means the averaging sign, I ₁ and I ₂ are the average intensities of interfering radiation, Δφ (t) = φ ₁ (t) -φ ₂ (t) is the phase difference.

Moreover, since Δt >> τ ₀ is the coherence time (Fig. 11), an interference pattern is recorded, averaged over a larger coherence time τ ₀ . If the intensities of both interfering waves are the same I ₁ = I ₂ = I ₀ , then I = 2I ₀ (1 + coskΔ). In this case, I _max = 4I ₀ , I _min = 0.

In case of interference:

a) the waves should have the same (or close) frequencies so that the picture resulting from the superposition of the waves does not change in time (or does not change very quickly) (temporal coherence);

b) the waves must be unidirectional (or have a close direction) (spatial coherence).

If in a homogeneous and isotropic medium two point sources S ₁ and S ₂ excite two simultaneously propagating sinusoidal spherical waves s ₁ and s ₂ , then at point B there will arise an oscillation, according to the superposition principle, equal to s = s ₁ + s ₂ . According to the formula of a spherical wave:

, $$s_{\mathrm{one}}=\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\sin \left({\omega }_{\mathrm{one}}t-k_{\mathrm{one}}{r}_{\mathrm{one}}+{\alpha }_{\mathrm{one}}\right)=\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\sin {\Phi }_{\mathrm{one}}$$

,

, $${\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">s</figure-callout>}}_2=\frac{A_2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\sin \left({\omega }_{2}t-k_2{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2+{\alpha }_2\right)=\frac{A_2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\mathrm{<figure-callout\; id="2"\; label="sin\; \Phi "\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">sin\; </figure-callout>}{\Phi }_{}{}_2$$

,

); ω₁ и ω₂ - циклические частоты каждой волны; α₁ и α₂ - начальные фазы; r₁ и r₂ - расстояния от точки М до точечных источников B₁ и B₂.where Φ ₁ = ω ₁ tk ₁ r ₁ + α ₁ and Φ ₂ = ω ₂ tk ₂ r ₁ + α ₂ are the phases of the propagating waves; k ₁ and k ₂ are wave numbers ( $$k=\frac{\omega }{\nu }=\frac{2\pi }{\lambda }$$

); ω ₁ and ω ₂ are the cyclic frequencies of each wave; α ₁ and α ₂ are the initial phases; r ₁ and r ₂ are the distances from point M to point sources B ₁ and B ₂ .

, амплитуда $$\frac{A}{r}$$

и фаза Φ равны: $$\frac{A}{r}=\sqrt{{\left(\frac{A_1}{r_1}\right)}^2+{\left(\frac{A_2}{r_2}\right)}^2+2\frac{A_1}{r_1}\frac{A_2}{r_2}\cos \left({\Phi }_2-{\Phi }_1\right)}$$

, $$\Phi =arctg\frac{\frac{A_1}{r_1}\sin {\Phi }_1+\frac{A_2}{r_2}\sin {\Phi }_2}{\frac{A_1}{r_1}\cos {\Phi }_1+\frac{A_2}{r_2}\cos {\Phi }_2}$$

Φ₂-Φ₁=(ω₁-ω₂)t-(k₂r₂-k₁r₁)+(α₂-α₁), где $$k_1=\frac{{\omega }_1}{\nu }$$

, $$k_2=\frac{{\omega }_2}{\nu }$$

, ν - скорость распространения волны, одинаковая для обеих волн в данной среде.In the resulting wave $$s=s_{\mathrm{one}}+{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">s</figure-callout>}}_2=\frac{A}{r}\sin \Phi$$

amplitude $$\frac{A}{r}$$

and phase Φ are equal to: $$\frac{A}{r}=\sqrt{{\left(\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\right)}^2+{\left(\frac{A_2}{r_2}\right)}^2+2\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\frac{A_2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\cos \left({\Phi }_2-{\Phi }_{\mathrm{one}}\right)}$$

, $$\Phi =arctg\frac{\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\sin {\Phi }_{\mathrm{one}}+\frac{A_2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\sin {\Phi }_2}{\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\cos {\Phi }_{\mathrm{one}}+\frac{A_2}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\cos {\Phi }_2}$$

Φ ₂ -Φ ₁ = (ω ₁ -ω ₂ ) t- (k ₂ r ₂ -k ₁ r ₁ ) + (α ₂ -α ₁ ), where $$k_{\mathrm{one}}=\frac{{\omega }_{\mathrm{one}}}{\nu }$$

, $${\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">k</figure-callout>}}_2=\frac{{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2}{\nu }$$

, ν is the wave propagation velocity, the same for both waves in a given medium.

For coherent waves ¹ ( ¹ Two sinusoidal coherent waves have the same frequency and constant phase difference.) (Ω ₁ = ω ₂ = ω) under the condition α ₂ -α ₁ = 0

, $$\frac{A}{r}=\sqrt{{\left(\frac{A_1}{r_1}\right)}^2+{\left(\frac{A_2}{r_2}\right)}^2+\frac{2A_1{A}_2}{r_1{r}_2}\cos k\left(r_2-r_1\right)}$$

. $${\Phi }_2-{\Phi }_{\mathrm{one}}=-\frac{\omega }{\nu }\left(r_2-r_{\mathrm{one}}\right)=-k\left(r_2-r_{\mathrm{one}}\right)$$

, $$\frac{A}{r}=\sqrt{{\left(\frac{A_{\mathrm{one}}}{r_{\mathrm{one}}}\right)}^2+{\left(\frac{A_2}{r_2}\right)}^2+\frac{2A_{\mathrm{one}}{A}_2}{r_{\mathrm{one}}{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}\cos k\left(r_2-r_{\mathrm{one}}\right)}$$

.

The results of physical modeling of interference are shown in Fig.5.

), причем волны в данной точке приходят с одинаковыми фазами и усиливают друг друга.The oscillation amplitude is maximum (A / r = A ₁ / r ₁ + A ₂ / r ₂ ) at all points of the medium for which k (r ₂ -r ₁ ) = 2mπ, where m = 0, ± 1, ± 2, ... (m is an integer) or r ₂ -r ₁ = mλ, (since $$k=\frac{2\pi }{\lambda }$$

), and the waves at a given point come with the same phases and reinforce each other.

. Волны приходят в заданную точку в противофазе и гасят друг друга.The oscillation amplitude is minimal (A / r = | A ₁ / r ₁ -A ₂ / r ₂ |) at all points of the medium for which k (r ₂ -r ₁ ) = (2m + 1) π, where m = 0, 1, 2, ... (m - natural) or $$\Delta =r_2-r_{\mathrm{one}}=\left(2m+\mathrm{one}\right)\frac{\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}{2}$$

. Waves arrive at a given point in antiphase and cancel each other out.

The minimum and maximum conditions are reduced to the fact that the path difference ² ( ^{2 the} path difference of two interfering waves to a point is the distance difference r2-r1 = Δ from the considered point to the sources S ₁ and S _2. ) Waves Δ = r ₂ - r ₁ = const. This expression defines the equation of hyperbola with foci at points S ₁ and S ₂ (Fig.6). The set of points at which the resulting oscillation is enhanced (weakened) is a family of hyperbolas. Between two interference maxima are interference minima, i.e. during interference, the energy of the waves is redistributed in space.

When adding two coherent unidirectional sinusoids, the interference points are on the same line along which the maxima of the sinusoids (minima) coincide in space and they mutually amplify (weaken), i.e. for the phase difference of the waves being added Δφ = (φ ₂ -φ ₁ ) and the path difference Δ = r ₂ -r ₁ at the point in space kΔ-Δφ = ± 2mπ, an interference maximum will be observed, and for kΔ-Δφ = ± 2 (m-1 ) π is the interference minimum.

When adding two coherent opposite directional sinusoids, the interference points are also on the same straight line along which the maxima of the sinusoids (minima) coincide in space and when the radiation is synchronized, they mutually amplify (attenuate), which determines the occurrence of a standing wave.

Radiation from a pair of point sources. Oscillations from a solitary source at points of a plane spaced a large but finite distance l from it. In this case, we restrict ourselves to a small compared with l displacement of the observation point from the point of incidence of the perpendicular drawn from the wave source S to the plane at small x values. Draw a straight line segment from the wave source to the observation point with the x coordinate and perpendicular to the coordinate axis (Fig. 7). Set aside a segment of length l from the source’s location along the hypotenuse of the triangle and connect the end of this segment to the point x _S , the point of incidence of the perpendicular. The angle at the apex of an isosceles triangle is θ≈x / l, and the base makes an angle θ / 2 with the 0X axis. Thus, the difference in the path of the rays

ΔL≈xsin (θ / 2) ≈xθ / 2≈x ² / 2l,

and the phase difference of the oscillations at these points

Δφ (x) = 2πΔL / λ = πx ² / lλ,

where x is the shift of the observation point from the initial coordinate.

We determine the position of the maximum (minimum) for which, according to the Pythagorean theorem, we determine d ₁ and d ₂ (Fig. 8)

; $$d_2^2=L^2+{\left(x+l/2\right)}^2$$

. $$d_{\mathrm{one}}^2={\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">L</figure-callout>}}^2+{\left(x-l/2\right)}^2$$

; $${\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">d</figure-callout>}}_2^2={\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">L</figure-callout>}}^2+{\left(x+l/2\right)}^2$$

.

Find the difference

. $${\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">d</figure-callout>}}_2^2-d_{\mathrm{one}}^2=\left(d_2-d_{\mathrm{one}}\right)\left({\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">d</figure-callout>}}_2+d_{\mathrm{one}}\right)={\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">L</figure-callout>}}^2+{\left(x+l/2\right)}^2-L^2-{\left(x-l/2\right)}^2=2xl$$

.

those. geometric path difference

Δd = d ₂ -d ₁ = 2xl / (d ₂ + d ₁ ).

Having determined the area of the triangle S ₁ MS ₂ and taking into account that it is equal to half the area of the quadrangle S ₁ KNS ₂ , we obtain the condition in the form

L × l = d ₁ × d ₂ sinθ = d ₁ × d ₂ × θ,

which determines the quadratic equation

или $$d_1^2+\Delta d{d}_1-\frac{L\times l}{\theta }=0$$

, решение которого $$\frac{L\times l}{\theta }L\times l/\theta =d_{\mathrm{one}}\times {\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">d</figure-callout>}}_2=d_{\mathrm{one}}\left(d_{\mathrm{one}}+\Delta d\right)$$

or $$d_{\mathrm{one}}^2+\Delta d{d}_{\mathrm{one}}-\frac{L\times l}{\theta }=0$$

whose solution

. $$d_{\mathrm{one}}=-\frac{\mathrm{<figure-callout\; id="2"\; label="\Delta \; d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}d}{2}\pm \sqrt{\frac{\mathrm{<figure-callout\; id="2"\; label="\Delta \; d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{d}^{}{}^2}{\mathrm{four}}+\frac{L\times l}{\theta }}$$

.

Moreover, since d ₁ is a positive quantity, then

. $${\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">d</figure-callout>}}_2+d_{\mathrm{one}}=2d_{\mathrm{one}}+\Delta d=2\sqrt{\frac{\mathrm{<figure-callout\; id="2"\; label="\Delta \; d"\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{d}^{}{}^2}{\mathrm{four}}+\frac{L\times l}{\theta }}$$

.

. При этом условие максимума kλ=x_maxl/L возможно при x_max=kλL/l, a условие минимума $$\left(2k+1\right)\frac{\lambda }{2}=\frac{x_{\min }l}{L}$$

при $$x_{\min }\left(2k+1\right)\frac{\lambda }{2l}L$$

.From this expression, for d << L, the sum is d ₂ + d ₁ ≈2L, and the stroke difference is: $$\Delta d=\frac{xl}{L}$$

. Moreover, the maximum condition kλ = x _max l / L is possible at x _max = kλL / l, and the minimum condition $$\left(2k+\mathrm{one}\right)\frac{\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="00000046.png,00000050.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}{2}=\frac{x_{\min }l}{L}$$

at $$x_{\min }\left(2k+\mathrm{one}\right)\frac{\lambda }{2l}L$$

.

Where does the width of the interference pattern ³ come from ( ³ The width of the interference pattern is the distance between two maxima (minima).) (Fig. 9)

Δx = λL / l.

For two point sources located at a distance l from each other and at a distance L from the observation plane, the phase difference of the oscillations at point x

Δφ = π [(x + l / 2) ² - (xl / 2) ² ] / lλ.

After squaring we get:

. $$\Delta \varphi =\pi \frac{2l}{L\lambda }x$$

.

Adding these oscillations, we have the amplitude (figure 10)

, $${\xi }_{0\Sigma }=2{\xi }_0\cos \left(\frac{\Delta \varphi }{2}\right)=2{\xi }_0\cos \left(\pi \frac{l}{L\lambda }x\right)$$

,

which has a maximum value of 2ξ ₀ at points spaced apart by Δx.

The central maximum is observed at x = 0. When moving away from the center, the difference in the path of the rays from the sources S ₁ and S ₂ increases. If the path difference is greater than the coherence length, then the amplitude of the total oscillations changes according to the law

. $${\xi }_0\cos \left(\frac{{\omega }_2-{\omega }_{\mathrm{one}}}{2}t\right)$$

.

The phase change over time Δt is determined by the condition

; $$\Delta t=\frac{2\pi }{{\omega }_2-{\omega }_1}=\frac{2\pi }{\Delta \omega }$$

, $$\frac{{\omega }_2-{\omega }_{\mathrm{one}}}{2}\Delta t=\pi$$

; $$\Delta t=\frac{2\pi }{{\omega }_2-{\omega }_{\mathrm{one}}}=\frac{2\pi }{\Delta \omega }$$

,

and the coherence length

l _coh = Δtc = 2πc / Δω.

Interference of quasimonochromatic waves. Real radiations are represented as trains ⁴ ( ⁴ trains are “scraps” of quasimonochromatic oscillations of finite duration (correlation or coherence time) τ0.) (Fig. 11), i.e. slowly varying random functions of time with amplitude a (t) and phase φ (t):

E (t) = a (t) cos [ω ₀ t + φ (t)].

The train has a spatial length equal to cτ, where c is the speed of light. In this case, the phase of the wave remains constant over time intervals of coherence τ.

The uncertainty relation determines the relationship between the duration of the process in time and the width of its spectrum

τ ₀ Δω≈2π,

those. the spectrum of the process with a coherence time τ ₀ has a width of the order of Δω≈2π / τ ₀ . For τ ₀ >> T we arrive at the strong inequality Δω << ω ₀ , i.e. the process is quasi-monochromatic.

With wave interference, the difference in the path of the rays arriving at the observation point should not be large. The interference is caused by vibrations related to one train. The maximum allowable difference in stroke during interference is

Δ _max ≈cτ ₀ ≈2πc / Δω≈λ ² / Δλ, m _max ≈Δ _max / λ≈λ / Δλ≈ω ₀ / Δω,

where m _max is the maximum order of interference; Δλ and Δω are the width of the spectral interval.

3. To control the formation of interference patterns in the system go into synchronization and measurement mode (figure 4). In this mode, to measure the distance l between the interacting RIOs, the clock generator 5 generates a clock from the command to the slave RIO (point Ex _to ) (Fig. 12), receives it as a slave RIO (point B _in ) and relays to the command RIO (exit point _in ) that receives it in turn (point Bx _k) and generates a second clock pulse (point O _k) for the slave RIO. In the meter slots IVI 9 measured transfer time clock for each RIO Δt _k and Δt _in, and with the processing clock time Δt ₀ in each RIO is calculated in the calculator Calcd. 10 the distance between them as (Fig)

$$\left(l=\frac{c\left(\Delta t_{в}-2\Delta t_0\right)}{2}\right)$$

. $$l=\frac{c\left(\Delta t_{\mathrm{to}}-2\Delta t_0\right)}{2}$$

$$\left(l=\frac{c\left(\Delta t_{\mathrm{at}}-2\Delta t_0\right)}{2}\right)$$

.

Having set the coefficient of multiplicity m = l / λ from the obtained distance between the RIO l, the wavelength of the given radiation λ is determined and calculated in the calculator Calcul. 10 for the time Δt _{0 the} frequency f of radiation in the mode of emission of false signals

f = mc / l.

At the same time, it is assumed that the standing wavelength is ⁵ ( ^{5 The} standing wave is a wave generated when two waves of the same frequency and amplitude propagating towards each other are superimposed. The standing wave does not transfer energy, since energy is transferred in equal amounts of traveling and reflected waves.) is equal to half the length of the added waves [2]:

λ _Art. = λ / 2.

. В результате возникает стоячая волна на прямой S_кS_в между РИО и формируется интерференционное поле от взаимодействующих РИО.After this, false signals are generated by the generator G 11 in the form of a train of coherent circular radio emission with a coherence time Δt. To do this, the radiation between the interacting RIOs is synchronized by turning on the radiation of coherent circular radio emission by the generator G 11 for the slave RIO after calculating the radiation frequency f, and the delay in the start of the radiation of coherent circular radio emission from the command RIO is equal to the time it takes for the clock to go to the output of the RIO $${\tau }_{\mathrm{to}}=\frac{\Delta t_{\mathrm{to}}}{2}-\Delta t_0+\Delta t_0=\frac{\Delta t_{\mathrm{to}}}{2}$$

. As a result, a standing wave arises on the line S _to S _in between the RIO and an interference field is formed from the interacting RIO.

The industrial applicability of the method lies in the possibility of its use to protect military-industrial RIOs from a radio-guided WTO and to implement the steps of the method on the currently existing elemental base.

LITERATURE

1. Rodionov B.I., Novikov N.N. Cruise missiles in a naval battle. Based on materials from an open foreign press. - M .: Military Publishing. - 1987. - 215 p.

2. Herod I.E. Wave processes. Basic laws. Physics course. T.3. - M .: Higher school. - 1993 .-- 253 p.

Claims (6)

1. A method of protecting a radio-emitted object from a radio-guided high-precision weapon with a homing head controlled by selecting the best points in the energy sense of the detected radio emission, which consists in emitting false signals, which determines the formation of the trajectory of a radio-guided high-precision weapon, leading it to an area safe for the radio-emitted object, characterized in that they form a barrier zone of interacting radio-emitted objects, in which the capture of the head of ca guidance and withdrawal of radio-guided high-precision weapons by a homing system in directions that are safe for the protected radiated object, for which they periodically remember the current parameters of the radio mode of the interacting radio-emitted objects and stop their radio exchange, switch to the measurement and synchronization mode, while forming a clock pulse from the command to the slave radio-emitted object , receive it by the slave radio-emitted object and relay it to the command radio-emitted object, which is received maet it in turn and generates a slave clock leaky second object, wherein the measured transfer time clock for each leaky object _to Δt and Δt _in with a time Δt ₀ sync processing in each leaky object calculated distance between them
$$l=\frac{c\left(\Delta t_{\mathrm{to}}-2\Delta t_0\right)}{2}\left(l=\frac{c\left(\Delta t_{\mathrm{at}}-2\Delta t_0\right)}{2}\right)$$

,
set the coefficient of multiplicity m = l / λ of the distance between the radiated objects l and the wavelength of a given radiation λ and calculate for a time τ _{0 the} frequency f of radiation in the mode of emission of false signals
f = mc / l, where c is the speed of light,
Then they switch to the mode of emission of false signals in the form of a train of coherent circular radio emission with a coherence time Δt, for which they synchronize the radiation between interacting radio emitted objects by turning on the radiation of coherent circular radio emission for the driven radio emitted object after calculating the radiation frequency f, and the delay in the start of radiation of coherent circular radio emission command radio emitted object for a while
$${\tau }_{\mathrm{to}}=\frac{\Delta t_{\mathrm{to}}}{2}+{\tau }_0$$

,
which ensures the occurrence of a standing wave between radio-emitted objects and determines the mode of coherent circular radio emission, which forms an interference field from interacting radio-emitted objects, and as the radio-guided high-precision weapon approaches the target, it selects the best in the energy sense points of the interference field of the radio emission, it goes to the central an interference strip that displays a radio-guided high-precision weapon to a virtual target, and the length of erentnosti l _coh, which determines the depth of a skirt area to effectively capture and withdrawal radionavodimogo precision weapon by an interference radio field to the virtual target,
l _coh = Δtc = 2πc / Δω≤R,
where R is the range of coherent circular radio emission
$$R=\frac{c}{\mathrm{four}\pi f}\sqrt{\frac{P_{Pd}{\eta }_{\mathrm{one}}{G}_{\mathrm{one}}{\eta }_2{G}_2}{P_{G\mathrm{FROM}N0}}}$$

,
where Р _ГСН0 - signal power at the input of the homing head in free space; R _PD - transmitter power; η ₁ , η ₂ - the efficiency of the transmitting and receiving feeder lines; G ₁ , G ₂ - antenna gain; f is the radiation frequency in the mode of coherent circular radio emission. 2. The system according to the method according to claim 1, consisting of two identical devices, each of which contains a receiver, a transmitter, two pulse shapers, a pulse shaper, three switch blocks, a time interval meter, a calculator, a generator, a control unit, a high-frequency amplifier, an antenna matching unit, an antenna, a delay element and a “Command-Slave” switch of operation modes, the output of the receiver being connected to the input of the first block of switches and through the first pulse shaper and the first switch There are operating modes for the first input of the control unit, the second input of which is connected to the "Start" input of the device through the second pulse shaper, the first output of the first switch block is connected to the "Output" output of the device, and its second output is connected to the first input of the clock generator and the meter input time intervals, the information outputs of the latter are connected to the first information inputs of the calculator, the second information inputs of which are connected to the inputs of the "Specification of the coefficient of multiplicity", and the output of the windows measuring a time interval meter with a control input of the calculator, the information outputs of which are connected to the inputs of the frequency generator, and the output of the calculation end of the calculator through the third contacts of the mode switch with the start input of the generator directly and through the delay element, the first output of the control unit is connected to the input control of the first block of switches and the second block of switches, and through the second contact of the mode switch with the second input of the shaper sync x, the output of the latter is connected to the first information input of the second block of switches, the input “Input” of the device is connected to the second information input of which, and the output is to the input of the transmitter, the output of which is connected to the first information input of the third block of switches, the second information input of which is connected to the output of the generator , the control input with the second output of the control unit, and the output through the high-frequency amplifier and the matching unit with the antenna, the second output of which is connected to the input of the receiver. 3. The method according to claim 1, characterized in that the zone into which the WTO is withdrawn is located between the protected RIOs, the length of which 1 for the WTO with the combat radius r _be with a safety margin δ of RIO protection is chosen equal to
l≥2r _be + δ,
and the virtual target in the zone is located in the middle between the protected RIOs. 4. The method according to claim 1, characterized in that the safety factor δ of RIO protection is determined by the range of the WTO due to its remaining energy resource after reaching the virtual target. 5. The method according to claim 1, characterized in that the power of the attacked transmitters R _PD in the circular radio mode is chosen so that in the coordinate of the virtual target the power of the resulting field exceeds the maximum radiation value at the input of the GOS P _GOSmax , which leads to dazzle and exit GOS failure, i.e.
$$P_{Pd}\ge \frac{{\pi }^2{l}^2{P}_{G\mathrm{FROM}N\max }{f}^2}{{\eta }_{\mathrm{one}}{G}_{\mathrm{one}}{\eta }_2{G}_2{c}^2}$$

. 6. The method according to claim 1, characterized in that the transition from the radio mode of the interacting RIO to the radio emission mode is performed with a period
$$\Delta t\le \frac{\mathrm{one}}{2F_{\max }}$$

,
where F _max - the maximum frequency of the spectrum of the information message.

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