RU2434240C1 - Radio source and direction finder orientation determining method - Google Patents

Abstract

FIELD: radio engineering. ^ SUBSTANCE: radiated signal is received with direction-finding antenna consisting of M identical antennae the focal axes of which are shifted relative to each other in direction finding plane so that adjacent antenna directivity diagrams form identical direction-finding characteristics, and the sum of M antennae superimposes the whole 360 surveillance area; received signals are distributed along three identical receiving devices; at that, view of the whole surveillance area is performed by electronic switching of M outputs of direction-finding antenna to inputs of three receiving devices so that to inputs of receiving devices for the time of determination of radio source direction there always simultaneously connected are three adjacent antennae; in each of the receiving devices the received signals are distributed along identical frequency sub-bands in each of which the signals are amplified and detected; detection result is amplified with logarithmic video amplifier; power of amplified signals is measured considering corrections for nonidentity of transfer factors of receiving devices, which is determined and stored at periodic calibration of receiving devices in each frequency sub-band and in dynamic range of input signals; as per ratio of powers there determined is frequency sub-band in which the signals has been received, and for the signals having maximum level in the receiving device connected to central antenna of the three adjacent antennae; radio source direction is determined as per direction-finding characteristics formed with central antenna and one of the adjacent antennae (right or left), in which the signal power is higher as per the appropriate formulae. At calculations the slope value of direction-finding characteristic is assumed considering frequency sub-band in which the signal has been received. Direction finder includes multi-beam direction-finding antenna consisting of M identical antennae, nondirectional antenna, four identical receiving devices (three for direction finding and one for compensation of reception along side lobes of direction-finding antennae), each of which represents multi-channel receiver, switch, directional coupler, synthesiser of working frequencies, and analysis and control device. ^ EFFECT: increasing sensitivity and direction-finding accuracy and quick action. ^ 2 cl, 5 dwg

Description

The invention relates to radio engineering and can be used in systems of radio monitoring and radio intelligence to determine the direction of the source of radio emission.

Known methods for direction finding of radio signals and direction finders for their implementation, implementing the correlation-interferometric method of direction finding (RF patent No. 2190236 from 09/13/2000, RF patent No. 2201599 from 03/27/2002, RF patent No. 2263327 from 10/27/2005, RF patent No. 2341811 dated December 20, 2008).

A limitation of these methods and devices is the relatively narrow frequency band of simultaneous reconnaissance.

A known method of detecting and determining the bearing and frequency of the IRI, which implements correlation processing based on a static analysis of the spectral energy densities of the signal and noise (RF patent No. 2190236 from 09/27/2002). The limitations of this method is a sufficiently large time for conducting static analysis.

Also known amplitude and phase direction finders (AS USSR No. 1840389, publ. 20.11.06, and applications JP 2005062144, publ. 10.03.05, US 2006158375, publ. 07.20.06, CN 101206257, publ. June 25, 2008, WO 2005073749, publ. August 11, 2005).

The limitations of the amplitude direction finders are insufficiently high direction finding accuracy due to errors caused by the non-identity of the gain of the receiving channels of the direction finder, especially in a wide frequency range.

The limitations of phase direction finders are the relatively narrow frequency band of simultaneous reconnaissance and the limited zone of unambiguous direction finding, which necessitates the use of multi-base direction finding methods.

Closest to the proposed method for determining the direction of the radio source, which is part of the group of inventions, is a method for amplitude direction finding of radio sources (RF patent No. 2319975 of 03.20.2008), in which the emitted signal is received by M identical antennas whose focal axes are shifted in the plane direction finding one relative to another so that the radiation patterns of adjacent antennas intersect at a level of no more than 3 decibels, and all M antennas in total overlap the direction finding sector 360 °. The received signals are distributed over M identical receiving channels, in each of which the signal received in it is amplified, detected, the detection result is amplified in a logarithmic amplifier, the power of the amplified signals in the channel with a maximum level is measured and in two adjacent signals and the ratio of the measured signal powers is determined direction to the radiation source, calculation of the direction φ _and to the source of the emitted signal is carried out according to the formulas:

φ _and = φ _N + β · sign (P _{N + 1} -P _N-1 ),

where β is the module of the angular deviation of the direction to the direction-finding radiation source from the focal axis of the antenna of the receiving channel with the maximum signal level;

δ ₁ , δ ₂ , δ ₃ - modulus of the normalized relative (in decibels) antenna gain with angular deviations of the signal arrival direction from its focal axis θ ₀ , 4/3 θ ₀ and 2/3 θ _0, respectively;

N is the number of the receiving channel with the maximum signal level;

P _n , P _{n + 1} , P _n-1 - relative, measured from the sensitivity level in decibels, power levels of the received signal in the N-th receiving channel and adjacent to it on the right and left, respectively;

φ _N is the direction of the focal axis of the antenna of the N-th receiving channel.

This method is selected as a prototype.

The limitations of this method are:

- low sensitivity, since in order to detect a signal simultaneously in three adjacent channels of the RPU, it is necessary to have a margin in sensitivity of the direction finder of at least 15 dB;

- when working in a wide range of frequencies and a large dynamic range of input signals, it is possible to reduce the accuracy of direction finding due to the non-identical amplification factors of the different channels of the RPU and the change in the width of the antenna paths, and therefore the ratio of signal levels in adjacent channels;

- a rather high complexity of implementation due to the large number of receiving channels.

Closest to the proposed direction finder according to the principle of construction is the direction finder according to the patent DE 3347068 from 03/26/92, a diagram of which is shown in figure 1. The direction finder comprises an omnidirectional antenna 1, a multi-channel radio receiving device 2, a power divider 3, directional direction-finding antennas 4, mixers 5, and a computing device 6.

The principle of operation of the direction finder is as follows. Omni-directional antenna 1 and direction-finding antennas 4 cover the entire operating frequency range. Multichannel radio receiver 2 contains m adjacent frequency channels that span the entire operating frequency range. When a radio source is detected by an omnidirectional antenna 1 and the jth frequency channel of a multichannel radio receiving device 2, the signal is extracted, amplified, and fed through a power divider 3 to all mixers 5, which are tuned to the frequency of the received signal. The computing device 6 determines the direction to the radio source by the known single-pulse amplitude method from the ratio of signal levels in adjacent direction finding channels.

This direction finder is selected as a prototype of the claimed direction finder.

The limitation of this direction finder is:

- low speed, since the determination of the direction of each of the detected omnidirectional antenna sources of radio emission is carried out sequentially in time;

- low sensitivity, since the sensitivity of the direction finder is determined by the reception channel with an omnidirectional antenna with a low gain, and not a directional direction finding antenna, in which the gain is much higher.

The main objective, the solution of which is claimed by the claimed method of determining the direction to the source of radio emission and direction finder, is to improve the basic technical characteristics.

A single technical result achieved in the implementation of the claimed group of inventions is to increase the sensitivity and accuracy of direction finding, as well as speed.

The specified technical result is achieved by the fact that in the known method of amplitude direction finding of radio emission sources, in which the emitted signal is received by a direction-finding antenna consisting of M identical antennas whose focal axes are shifted relative to each other in the direction-finding plane so that adjacent directional patterns of the antennas form identical direction-finding characteristics, and in total M antennas cover the entire 360 ° observation area, according to the invention, the received signals are distributed over three idents receiving antennas, while the entire observation area is surveyed by electronically switching the M outputs of the direction-finding antenna to the inputs of the three receiving devices in such a way that three adjacent antennas are always connected to the inputs of the receiving devices at the time of determining the direction to the radio emission source, received signals in each receiving device distributed over identical frequency subbands, in each of which the signals are amplified, detected, the detection result is amplified in a logarithmic form an amplifier, measure the power of the amplified signals, taking into account corrections for the non-identity of the transmission coefficients of the receiving devices, which is determined and stored during periodic calibration of the receiving devices in each frequency sub-range and in the dynamic range of the input signals, the frequency sub-range in which the signal is received is determined by the power ratio, and for signals having the maximum level at the receiver, connected to the central of three adjacent antennas define the direction β _i to i-th source radioizlu eniya characteristics of DF formed by the central and one of the adjacent antennas (right or left), with a greater signal power for the j-th frequency subband, wherein the received signal by the formulas:

β _i = β _RSNk ± Δβ _i ,

where β _PCHk , degree is the bearing value for the equal-signal direction of the selected k-th direction-finding characteristic.

The value + Δβ is taken when determining the direction from the direction-finding characteristic formed by the central and left adjacent antennas, and - Δβ - when determining the direction from the direction-finding characteristic formed by the central and right adjacent antennas.

Δβ _i , degree = S (f _j ) · ΔP _i ,

where Δβ _i is the deviation of the direction to the i-th source of radio emission from the equal-signal direction of the selected k-th direction finding characteristic;

S (f _j ), degree / dB is the steepness of the direction-finding characteristic in the j-th frequency subband:

ΔP _i , dB = P _c -P _{l (p)} ± ΔP _k (f _j , P _i ),

where R _c , R _{l (p)} is the relative signal power level in the receiving device, connected respectively to the central, left (or right) of the three adjacent antennas;

ΔP _k (f _j , P _i ), dB is the non-identity of the transmission coefficients of the receiving devices connected to the central and left (or right) of the three adjacent antennas in the j-th frequency subband at a power level corresponding to the power of the input signal.

The value ΔP _k (f _j , P _i ) and the plus or minus sign are determined when calibrating the receiving devices according to the signals of the operating frequency synthesizer.

Obviously, two adjacent channels of a direction-finding antenna are sufficient to determine the direction. In the proposed method, three adjacent channels are used, since the left and right adjacent channels are additionally used to compensate for the reception on the near side lobes of the central antenna, thereby reducing the likelihood of false bearings with a high level of input signals.

The structure of the direction-finding patterns of the direction-finding antenna, explaining the essence of the method for determining the direction to the source of radio emission, is shown in figure 2.

The specified technical result is also achieved by the fact that in the direction finder containing a multi-beam direction-finding antenna, consisting of M identical antennas, the focal axes of which are shifted relative to each other in the direction-finding plane so that the radiation patterns of adjacent antennas form identical direction-finding characteristics, and in the sum of the radiation patterns M antennas cover the entire 360 ° viewing area, an omnidirectional receive compensation antenna along the side lobes, four identical receiving devices, each of which is a multi-channel receiver and analysis and control device, according to the invention, the outputs of a multi-beam direction-finding antenna through a switch having M inputs and three outputs and through a directional coupler are connected to the inputs of three receiving devices, and the switch, at any switching, provides simultaneous connection of the outputs of three adjacent antennas , the omnidirectional antenna is also connected through the directional coupler to the fourth receiving device, and the outputs of all four receiving stroystv connected to inputs of the analysis and control unit, the control outputs of which are connected to all the receivers, and the switch operating frequency synthesizer whose output is connected through a directional coupler to the inputs of all four receivers.

The invention is illustrated by drawings, which show

in Fig 1 is a structural diagram of the direction finder of the prototype;

on Fig 2 - the structure of the radiation patterns of the direction-finding antenna;

figure 3 is a structural diagram of a direction finder;

figure 4 is a structural diagram of a receiving device;

figure 5 - structural diagram of the amplifier of the Converter.

Since the claimed method is implemented in the operation of the device, its detailed description is given when describing the operation of the direction finder.

The direction finder (figure 3) contains a multi-beam direction-finding antenna 1, an omnidirectional antenna 2. The outputs of the direction-finding antenna 1 through a switch 3 and a directional coupler 4 are connected to the corresponding inputs of three multi-channel receiving devices 5, the output of the directional antenna 2 is connected through a directional coupler 4 to the input 4- th receiving device 5, the outputs of all receiving devices 5 are connected to an analysis and control device (UAU) 7, the control outputs of which are connected to switch 3, to all receiving devices 5 and synthesis yell operating frequency 6, which is output through the directional coupler 4 connected to the inputs of all the receiving devices 5.

A multi-beam direction-finding antenna 1 consists of M identical antennas, the focal axes of which are shifted relative to each other in the direction-finding plane so that adjacent antenna patterns form identical direction-finding characteristics. In total, M antennas overlap in the direction-finding plane the entire 360 ° observation area. Since the width of the partial MD in a wide frequency range can vary, the steepness of the direction-finding characteristic (HR) depends on the carrier frequency.

Under the slope of the HRP is understood as the dependence of the ratio of power in direction finding channels on the deviation from the equal-signal direction of the HRP.

Direction finding antenna 1 can be made in the form of M identical horn, log-periodic or other types of antennas, providing the desired structure of the beam.

Omnidirectional antenna 2 has a circular beam and can be made in the form of a biconical antenna.

A multi-beam direction-finding antenna 1 and an omnidirectional antenna 2 cover the entire operating frequency range.

Switch 3 contains M inputs according to the number of outputs of the multi-beam direction-finding antenna and three outputs and can be performed on the basis of 3 4 × 1 switches, i.e. having 4 entrances and one exit. The switch includes a control device that unlocks (locks) the corresponding channels of switch 3 by commands from the analysis and control device 7. Switching should be carried out in such a way that three adjacent antennas of the multi-beam direction-finding antenna 1 are always connected to the inputs of the receiving devices 5.

The directional coupler 4 is intended for supplying the signals of the working frequency synthesizer 6 to the inputs of all receiving devices 5 with the aim of calibrating them in the frequency range. The attenuation of the directional coupler 4 in the directions 1-1, 2-2, 3-3, 4-4 is minimal in order to prevent a decrease in the direction finder sensitivity. The attenuation of the signal in the directions 5-1, 5-2 5-3, 5-4 - at least 20 dB in order to eliminate the loss of power of the IRI signal.

Each of the receiving devices 5 is a superheterodyne two-stage multi-channel receiver. The structural diagram of one receiving device 5 is shown in Fig.4.

The composition of one receiving device 5 includes an amplifier converter 8, a multi-channel logarithmic detector 9, a preliminary processing device 10, and a buffer device 11.

The device (UAU) 7 contains a control device for the switch 3, the synthesizer of the working frequencies 6 and receiving devices 5, as well as a computing device. UAU 7 is a multiprocessor computing structure based on signal microprocessor devices and programmable logic integrated circuits (PLICs) (for example, type THS32DVC5402A, f. Texas Instruments, XC4VLX60FF668 f. Xilinx, AD9211 f. Analog Devices).

The operating frequency synthesizer 6 is based on commercially available voltage-controlled oscillators (for example, V585ME06 f-Z - comm. USA, K03-2700-433-R f. Met-Circuits, USA) and provides the formation of calibration microwave signals in the entire operating range frequencies and in the dynamic range of input signals.

The direction finder works as follows.

The observation zone is surveyed by electronically switching the outputs of the multi-beam direction-finding antenna 1, in such a way that three antennas with adjacent radiation patterns are always connected to the receiving devices 5 at the same time.

The direction finder operates in automatic mode, the observation zone is set from the outside, for example, from the control panel of the radio intelligence station, where the direction finder is included. If the observation zone is set, which is overlapped by one partial radiation pattern of the direction-finding antenna 1, then switching does not occur. In this mode, constant monitoring of individual radiation sources is carried out. If the observation area is not overlapped by one partial radiation pattern of the direction finding antenna 1, then the outputs of the direction finding antenna 1 are periodically switched according to the above algorithm. The time during which the observation zone does not switch is determined on the basis of the need for reliable detection of IRI and can be approximately no more than 20 ms.

The IRI signal received by the direction finding antenna 1 through the switch 3 and the directional coupler 4, is fed to the input of the amplifier of the Converter 8 of the receiving device 5.

The IRI signal received by the omnidirectional antenna 2, enters through the directional coupler 4 to the input of the fourth receiving device 5.

The block diagram of the amplifier of the Converter is shown in Fig.5.

The signal received by the amplifier, the converter 8 is amplified in the amplifier 12 and through the splitter 13 and the band-pass filters 14, providing separation by frequency subbands with a band Δf _i , is fed to one of the converters 15, where it is converted to an intermediate frequency f _n , then through a power divider 16 simultaneously arrives at the detectors 17 and the high-speed switch 19, the detected signal is fed to the control device 18, which opens the switch 19 and the microwave signal through the adder 20 is fed to the detector logarithmically multi-channel cue 9. Signals "KSK" (a sign of the presence of an IRI signal) through the control device 18 are fed to the UPR 10 to determine the carrier frequency of the radiation source. The switches 19 can also be controlled externally from the analysis and control device 7 through the buffer device 11.

The amplifier converter 8 is the first stage of a multi-channel superheterodyne receiver. The switches 19 are used to limit the band of frequencies being distributed by commands from UAU 7. If the switch 19 is closed by a command from UAU 7, the signal does not go further, if there is no command from UAU 7 to lock, then the switch 19 is opened by an incoming signal. The flag of the unlocking of the switch 19 (signal "KSK") is used as a sign of the presence of a signal in this sub-band.

The multi-channel logarithmic detector 9 is the second stage of the multi-channel superheterodyne receiver 5.

In the detector logarithmic multi-channel 9, the intermediate frequency signal is again amplified, the frequency range Δf _i is divided using bandpass filters into the same subbands Δf ₂ . Next, the microwave signal is detected, amplified by logarithmic video amplifiers and fed to the input of the corresponding channel of the preliminary processing device 10 (UPR). The number of inputs of the UPR 10 is equal to the number of outputs of the detector of the logarithmic multichannel 9. In each channel of the UPR 10, using the ADC, the video signal is converted into a digital code and the signal amplitude codes of the IRI are compared. The channel number of the logarithmic multichannel detector 9 and the indication of the operation of the switch of the amplifier of the converter 8 (signal "KSK") determines the value of the carrier frequency of the IRI f _i .

Information about the carrier frequency code and the signal amplitude is received through the buffer device 11 to UAU 7. In UAU 7, the IRI signal levels are compared for the value f _i , including the signals received by the omnidirectional antenna 2, and the number of the receiving device 5 is determined with the maximum signal amplitude. If the signal has a maximum amplitude in the channel of the receiving device 5, connected to the central of 3 adjacent direction-finding antennas 1, it is accepted for processing. Otherwise, processing stops. The value of the bearing of the i-th radio emission source β ₁ is determined in UAU 7 by a single-pulse amplitude method according to the formulas:

β _i = β _pcn ± Δβ _i ,

where β _rsn (degree) is the bearing value for the equal-signal direction of the selected direction-finding characteristic, the value (+ Δβ _i ) is taken when determining the direction from the direction-finding characteristic formed by the central and left adjacent antennas, and (-Δβ _i ) when determining the direction from the direction-finding characteristic formed by the central and right adjacent antennas.

Δβ _i , degree = S (f _j ) · ΔР _i ,

where Δβ _i is the deviation of the direction on the i-th IRI from the equal-signal direction to the selected direction-finding characteristic;

S (f _j ), degree / dB is the steepness of the direction-finding characteristic in the j-th frequency subband.

ΔP _i , dB = R _c -P _{l (p)} ± ΔP _k (f _j , P _i ),

where P _c , R _{l (p)} , dB is the relative signal power level in the receiving device connected to the central, left (or right) of the three adjacent antennas;

ΔP _k (f _j , P _i ) - the identity of the transmission coefficients of the receiving devices connected to the central and left (or right) of the three adjacent antennas in the j-th frequency subband, at a power level corresponding to the power of the input signal.

The value ΔP (f _j , P _i ) and the plus or minus sign are determined during calibration by the signals of the operating frequency synthesizer.

Thus, the AR is determined taking into account the periodic calibration of the paths of the receiving devices 5 using the signals of the frequency synthesizer 6, which allows to reduce the bearing error caused by the non-identical transmission coefficient of the receiving devices 5 in a wide frequency range and with a large dynamic range of input signals. Correction factors for calculating ΔР after calibration are stored in UAU 7. Calibration is performed in each frequency subband with a discrete channel of the logarithmic multichannel detector 10 Δf ₂ . The number of discrete in the dynamic range is determined by the characteristics of the receiving devices 5.

The calibration frequency is chosen so that it does not affect the main operation of the direction finder, and can be tens of minutes.

The fact that the calibration allows to reduce the error in determining the direction to the IRI due to the non-identity of the transmission coefficient of the receiving paths is confirmed by the following calculations.

Assume that

f (θ ₁ ) and f (θ ₂ ) are functions that describe partial radiation patterns of a direction-finding antenna;

To ₁ , To ₂ - gain of the receiving channels 1 and 2;

Δu - signal carrying information about the angle of arrival.

It can be shown that, provided that K ₁ , K _{2 are} linear functions, and the logarithm error is negligible

Δu '= lgk ₁ -lgk ₂ - error due to the non-identical transmission coefficients of the receiving channels.

When applying a calibration signal

As a result of subtracting signals 1 and 2, we obtain

Δu = logf (θ ₁ ) -lgf (θ ₂ ) + lgk ₁ (f _c ) -lgk ₂ (f _c ) -lgk ₂ (f _k ) + lgk ₂ (f _k )

Δu '= lgk ₁ (f _c ) -lgk ₁ (f _k ) + lgk ₂ (f _c ) -lgk ₂ (f _k ).

If k ₁ and k ₂ at the frequencies of the signal f _c and calibration f _k differ slightly, then the error due to the multi-channel decreases.

Bearing value β is averaged over the observation time in UAU 7 and issued to an external consumer.

If there are several IRIs in the observation zone, then the bearings are determined for each of them, and the signals of all IRIs are processed in parallel. After processing all the signals, a switching occurs and according to the above algorithm, the processing of IRI signals is carried out in the new spatial observation zone.

Thus, if the observation area is not overlapped by one partial radiation pattern of the direction finding antenna 1, then the outputs of the direction finding antenna 1 are switched until the entire observation area is viewed, then the cycle repeats.

Claims (2)

1. The method of determining the direction to the source of radio emission, in which the radiated signal is received by a direction-finding antenna, consisting of M identical antennas, the focal axes of which are shifted relative to each other in the direction-finding plane so that adjacent directional patterns of the antennas form identical direction-finding characteristics, and in total M antennas cover the entire 360 ° observation area, characterized in that the received signals are distributed over three identical receiving devices, while the overview of the entire 360 ° observation area carry out electronic switching of the M outputs of the direction-finding antenna to the inputs of three receiving devices, the switching being carried out in such a way that three adjacent antennas are always simultaneously connected to the inputs of the receiving devices at the time of determining the direction to the radio source, and in each receiving device the received signals are distributed over identical frequency subbands , in each of the frequency subbands, the signals are amplified, detected, the detection result is amplified by a logarithmic video amplifier m, the power of the amplified signals is measured taking into account corrections for the non-identity of the transmission coefficients of the receiving devices, which is determined and stored during periodic calibration of the receiving devices according to the frequency synthesizer signals in each frequency subband and in the dynamic range of the input signals, then the frequency subband is determined by the ratio of the measured amplified signal powers in which the signal is received, and for signals having a maximum level in the receiving device connected to the central of three adjacent a antenna, determine the direction of β _i to the i-th source of radio emission according to direction-finding characteristics formed by the central and one of the adjacent antennas (right or left), with a high signal level, with a slope value for the j-th frequency subband in which the signal is received, formulas:
β _i = β _pcn ± Δβ _i ,
where P _rsn (degree) is the bearing value for the equal-signal direction of the selected direction-finding characteristic, the value (+ Δβ _i ) is taken when determining the direction from the direction-finding characteristic formed by the central and left adjacent antennas, and (-Δβ _i ) - when determining the direction from the direction-finding characteristic formed by the central and right adjacent antennas, Δβ _i , degree = S (f _j ) · ΔP _i ,
where Δβ _i is the deviation of the direction to the i-th source of radio emission from the equal-signal direction of the selected direction-finding characteristic,
S (f _j ), degree / dB - steepness of direction-finding characteristic in j-th
frequency sub-band
ΔP _i , dB = R _c -P _{l (p)} ± ΔP _k (f _j , P _i ),
where R _c , R _{l (p)} , dB is the relative power level of the signal in the receiving device connected to the central, left (or right) of the three adjacent antennas,
ΔP _k (f _j , P _i ) is the identity of the transmission coefficients of the receiving devices connected to the central and left (or right) of three adjacent antennas in the jth frequency subband, at a power level corresponding to the power of the input signal, and the value ΔP (( f _j , P _i ) and the plus or minus sign are determined during calibration using the operating frequency synthesizer signals. 2. A direction finder containing a multi-beam direction-finding antenna, consisting of M identical antennas, the focal axes of which are shifted relative to each other in the direction-finding plane so that the radiation patterns of adjacent antennas form identical direction-finding characteristics, and in total radiation patterns of the M antennas cover the entire observation area 360 °, an omnidirectional reception compensation antenna along the side lobes, four identical receiving devices, each of which is a multi-channel receiver, and an antenna analysis and control device, characterized in that the outputs of the multi-beam direction-finding antenna through a switch having M inputs and three outputs and through a directional coupler are connected to the inputs of three receiving devices, and the switch, at any switching, provides simultaneous connection of the outputs of three adjacent antennas, the non-directional antenna also through a directional coupler it is connected to the fourth receiving device, and the outputs of all four receiving devices are connected to the inputs of the analysis and control device the control outputs of which are connected to all four receiving devices, a switch and an operating frequency synthesizer, the output of which through a directional coupler is connected to the inputs of all four receiving devices.

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