RU2679597C1 - Pulse-doppler airborne radar station operating method during detecting of air target - carrier of radio intelligence and active interference stations - Google Patents

Abstract

FIELD: radar ranging.SUBSTANCE: invention relates to the field of radar and can be used to improve the noise immunity of a pulse-Doppler airborne radar (ABR) when it is operating on radiation and detecting an air target (AT) - carrier of radio intelligence (RI) and active interference (AI) stations. Method consists in the formation of a high-frequency sequence of probe pulses at the original carrier frequency f, their amplification in power, radiation in the direction of the AT - carrier of RI stations and AI, the conversion of the reflected signals to intermediate frequencies, their selection in range and Doppler frequency, the conversion of signals into digital form, followed by their spectral analysis, at each reception of the signal reflected from the AT - carrier of the RI and AI stations, the measured value of the detection range Dcompared with the maximum value of the detection range Dwith the RI station of the radiated radar signal at the carrier frequency f, under condition D> Dit is decided that the ABR stealth during its radiation operation is provided and the RI station does not detect or recognize the structure and parameters of the radiated ABR signal at carrier frequency f, in this case, ABR noise immunity is ensured, since jamming by the active jamming station (AJS) is not be performed, otherwise simultaneously with an increase of n times, where n is an integer or fractional number greater than one, the time of coherent accumulation of the signal in the ABR receiver, reducing by n times the average radiated power of the ABR transmitter, switching to another carrier frequency f, where i=2, I, where I is the total number of carrier frequencies of the probing signal, until condition D> Dis met, which indicates the provision of noise immunity of the pulse-Doppler ABR.EFFECT: technical result achieved is to ensure the noise immunity of the pulse-Doppler ABR when it is operating on radiation and detecting the AT - the carrier of the RI and AI stations.1 cl, 1 dwg

Description

The invention relates to the field of radar and can be used to increase the noise immunity of a pulse-Doppler airborne radar station (radar) when it works on radiation and the detection of an air target - carrier stations of radio intelligence (RTR) and active interference.

A known method of functioning of a pulse-Doppler radar, which consists in the formation of a high-frequency sequence of probe pulses, their amplification in power, radiation into space, reception, amplification, conversion of reflected signals to intermediate frequencies, their selection in range and Doppler frequency, converting signals into digital form with their subsequent spectral analysis [1].

The disadvantage of this method is the impossibility of using it to always ensure the radar immunity when it is working on radiation when an air target is detected - carrier of RTR stations and active interference with their setting by the active interference station (SAR) of the effective interference at the carrier frequency of the probe signal, structure and parameters which can be recognized by the RTR station in the case of non-secrecy of the secrecy of the radar.

So, on the one hand, the range D of the _{radar for} detecting a target - carrier of RTR stations and active interference using a pulse-Doppler radar is determined by the expression [1]

Where

R _bls - the average radiated power of the transmitter;

T _kn - the time of coherent signal accumulation in the receiver, equal to the time of irradiation of an air target - carrier of RTR stations and active interference;

G _radar - directional coefficient of the transmitting antenna;

S _a is the effective area of the receiving antenna;

σ _rtr is the effective reflection surface of the aerial target - carrier of the RTR stations and active interference;

α _p - coefficient of signal energy loss during its processing;

N ₀ is the spectral density of the internal noise of the receiver;

R ₀ is the ratio of the signal energy to the spectral density of the noise, at which, with a given probability, the detection of an air target, the carrier of RTR stations and active interference, is provided.

On the other hand, the maximum detection range D _PTP station RTR emitted radar radar high-frequency sounding signal is determined by the expression [2]

Where

G _rtr is the directional coefficient of the receiving antenna of the RTR station;

λ _radar - wavelength radar;

P _rtr is the maximum value of the sensitivity of the receiver of the RTR station.

In this case, two situations are possible. The first situation when the detection range of the radar radiated by the RTR station exceeds the radar detection rate of the carrier of the RTR station and active interference, that is, D _PTP ≥D the _radar station The second situation, when the detection range of the airborne target of the carrier of RTR station and active interference exceeds the detection range of the station The RTR of the radar radar of the probe signal, i.e., B _{radar radar} ≥D _PTP .

Therefore, in the first case, the secrecy of the radar’s work on radiation is not ensured, and with the help of the RTR station the structure and parameters of the probing signal will be recognized, which will allow the radar to deliver an effective interference at the given carrier frequency using the SAP.

In the second case, the secrecy of the radar’s work on radiation will be ensured, which will not allow the RTR station to recognize the structure and parameters of the probing signal, and therefore put the effective interference at this carrier frequency.

Therefore, in order to ensure the stealth of the radar’s radar operation, and therefore the radar’s noise immunity as a whole, when detecting an air target - carrier of RTR stations and active interference, it is necessary to constantly monitor and maintain the condition

A known method of functioning of a pulse-Doppler radar upon detection of an air target - carrier of an RTR station, which consists in generating a high-frequency sequence of probe pulses at a constant carrier frequency, their amplification in power, radiation in the direction of an air target - carrier of an RTR station, receiving, amplifying, converting reflected signals to intermediate frequencies, their selection by range and Doppler frequency, the conversion of signals into digital form with their subsequent spectral analysis, while distance D _radar detection aerial target - RTR station carrier is determined by the expression (1), wherein at each reception signal reflected from the aerial target - station RTR carrier the measured value detection range D _radar compared with the maximum value detection range D _PTP station RTR emitted radar high-frequency probe signal defined by expression (2), when condition (3) is fulfilled, they decide that the secrecy of the radar station when it operates on radiation at a given carrier frequency of the probe signal provides The signal is transmitted and the RTR station does not detect and does not recognize the structure and parameters of the radar-emitting sounding radar of the probing signal, while the average radiated power R of the _radar transmitter, the time of irradiation of the air target carrier of the RTR station and the time T _kn of signal coherent accumulation in the radar receiver remain unchanged if the condition (3) is not satisfied, then the simultaneous increase in the n times, where n - an integer or fractional number greater than one, the irradiation time aerial target - carrier station RTR and time T _Vol coherent signal acquisition in the receiver radar and intelligence nshayut n times in average emitted power P _radar radar transmitter as long as the condition (3), which indicates the providing stealth operation radar radiation [3] will be satisfied.

The disadvantage of this method is the impossibility of using it to always ensure the noise immunity of the radar. This is due to the fact that if condition (3) is not satisfied, only the average radiated transmitter power R _radar transmitter and the time T _{kn of} coherent signal accumulation in the radar receiver are changed without changing the carrier frequency of the probing signal. Moreover, if condition (3) was not initially met, then using the RTR station the structure and parameters of the probing signal are recognized, and therefore, jamming will be carried out at the given carrier frequency of the probing signal from the SAP, that is, the above measures (reduction in the average radiated power the transmitter and an increase in the time of coherent accumulation of the sigal) will not make it possible to provide radar noise immunity as a whole when it operates on radiation and the detection of an air target - carrier of RTR stations and active interference.

The purpose of the invention is the provision of noise immunity of a pulsed-Doppler radar when operating on radiation and detecting an air target - carrier of RTR stations and active interference.

This goal is achieved by the fact that in the method of operation of a pulse-Doppler radar upon detection of an air target - carrier of RTR stations and active interference, which consists in the formation of a high-frequency sequence of probe pulses at the initial carrier frequency f ₁ , their amplification in power, radiation in the direction of the air target - carrier of RTR stations and active interference, reception, amplification, conversion of reflected signals to intermediate frequencies, their selection in range and Doppler frequency, signal conversion als in digital form with subsequent their spectral analysis, wherein the distance D _radar detection aerial target - carrier RTR stations and jamming is determined by expression (1), wherein at each reception signal reflected from the aerial target - carrier RTR stations and jamming, the measured value of the detection range D _{radar is} compared with the maximum value of the detection range D _PTP station RTR radiated radar radar high-frequency sounding signal at a carrier frequency f ₁ defined by expression (2), when the condition (3 ) make a decision that the radar safety of the radar during its work on radiation is ensured and the RTR station does not detect and does not recognize the structure and parameters of the radiated radar signal at the initial carrier frequency f ₁ , while the average radiated power R of the _radar transmitter, the time of irradiation of an air target - carrier RTR stations and jamming and time T _Vol coherent signal acquisition in the receiver radar remains unchanged in this case is provided by radar noise immunity, because the structure and parameters of the probing signal carrying boiling frequency f ₁ will not be recognized station RTR and jamming by the SAP at a carrier frequency f ₁ will not be performed, further, if the condition (3) is not satisfied, then simultaneously with the increase in n times, where n - an integer or a fractional number, greater than one, the irradiation time aerial target - carrier RTR stations and jamming and time T _Vol coherent accumulation signal to radar receiver, a decrease in the n times the average radiated power P _radar transmitter radar, transitioning to a different carrier frequency f _i where i = 2, I; I is the total number of carrier frequencies of the probing signal until condition (3) is fulfilled, which indicates that the pulse-Doppler airborne radar station is immune-protected when it is emitted and an air target is detected - carrier of RTR stations and active interference on the carrier frequency of the probing signal f _i, i.e. the structure and parameters of the probe signal in this case will not be recognized RTR station, and hence jamming by the SAP at a given carrier frequency zondiruyuscheg f _i signal will not be performed.

A new feature with a significant difference is the simultaneous:

increase in n times the time of irradiation of an air target - carrier of RTR stations and active interference and time T _kn coherent signal accumulation in the radar receiver;

a decrease in n times the average radiated power R _radar transmitter radar;

switching to another carrier frequency until condition (3) is satisfied,

which indicates the noise immunity of the radar operation on radiation at a given carrier frequency, that is, the structure and parameters of the probing signal in this case will not be recognized by the RTR station, and therefore, interference from the SAP side will not be carried out at this carrier frequency of the probing signal.

This feature has a significant difference, since it is not found in the known methods.

The use of a new feature will always ensure the noise immunity of a pulse-Doppler radar when operating on radiation and detecting an aerial target - carrier of RTR stations and active interference.

The figure shows a block diagram explaining the proposed method of functioning of a pulse-Doppler radar upon detection of an air target - carrier stations RTR and active interference.

The method of functioning of a pulse-Doppler radar upon detection of an air target - carrier of RTR stations and active interference is implemented as follows (figure).

Using a tunable master oscillator (ZG) 1, a synchronizer 2 and a modulator 3, high-frequency sequences of probe pulses are formed at the initial carrier frequency f ₁ , which are amplified in a high-frequency power amplifier (PM RF) with a controlled gain and through an antenna switch (AP) 5, the antenna (A) 6 is emitted in the direction of the aerial target, the carrier of the RTR stations and active interference. The signals reflected from the air target — the carrier of the RTR stations and active interference — are received by the antenna 6 and through the antenna switch 5 are fed to the radar receiver, which are amplified in the high-frequency amplifier (UHF) 7, converted in the conversion path 8 to intermediate frequencies (IF), and selected in range in the range selector 9 (SD) using selector pulses arriving at its input from the output of the synchronizer 2, and also are selected by the Doppler frequency in the converter 10, to the inputs of which the values of the orientation angles and the antenna pattern in the vertical and horizontal planes from the output of the goniometer channel (not shown in the diagram) and the value of the own speed of the radar carrier from the output of the navigation system (not shown in the diagram). In the converter 11, the signal from the analog form is converted to digital form, which is fed to the input of the fast Fourier transform unit 12 (FFT), where its spectral analysis is carried out, and from its output to the indicator.

At the same time, in the range meter (ID) 13, the range D of the _{radar for} detecting the radar of airborne target carrier of the RTR stations and active interference is measured, which is compared in the analyzer 15 with the maximum distance D _PTP calculated in the calculator (HF) 14 in accordance with formula (2) detecting by the RTR station of the radiated radar of the probing signal.

When condition (3) is fulfilled, the analyzer 15 makes a decision that the radar secrecy during its work on radiation is ensured and the RTR station does not detect and does not recognize the structure and parameters of the radiated radar signal at the initial carrier frequency f ₁ , while the average radiated power P _{radar of the} transmitter, the time of irradiation of an air target - carrier of RTR stations and active interference and the time T _{kn of} coherent signal accumulation in the radar receiver remain unchanged. In this case, radar noise immunity is ensured, since the structure and parameters of the probing signal at the carrier frequency f ₁ will not be recognized by the RTR station and jamming from the SAP side at the carrier frequency f ₁ will not be carried out. At the same time, signals are generated at the first 16, second 17, third 18, and fourth 19 outputs of the analyzer 15, which are prohibitory for changing, respectively, the time of coherent signal accumulation (equivalent bandwidth of one bit of the FFT algorithm) in the FFT block 12, the time of irradiation of an air target — the station carrier RTR and active interference, which is controlled by the antenna control system 20 (AMS), emitted by the average transmitter power, which is controlled in the high-frequency power amplifier 4 and the carrier frequency signal, generated at the output of the tunable master oscillator 1.

If condition (3) is not fulfilled, the analyzer 15 makes a decision that the noise immunity of the pulse-Doppler radar station when it is emitted and an air target is detected - carrier of RTR stations and active interference is not provided. At the same time, signals are generated at the first 16, second 17, third 18 and fourth 19 outputs of the analyzer 15, which are permissive to increase by n times, where n is an integer or fractional number greater than one, respectively, of the time of coherent signal accumulation in the FFT block 12 by increasing the number of samples of the FFT procedure at a constant sampling frequency of the signal in block 11, and the time of irradiation of an air target, the carrier of RTR stations and active interference, by controlling the radiation pattern of the radar antenna using antenna antenna control system 20 Thus, so that the time spent by the beam of the radiation pattern would be at the angular position at which the aerial target was detected - the carrier of the RTR stations and active interference, it would be equal to the time of coherent signal accumulation in the FFT unit 12, as well as the resolution signal to reduce by n times radiated average power of the radar transmitter by reducing the gain in the high-frequency power amplifier 4 and tuning in the tunable master generator 1 of the carrier frequency of the probe signal to the frequency f _i (where i = 2, I; I is the total number of carrier frequencies of the probing signal) until condition (3) is fulfilled, which indicates that the pulse-Doppler radar is provided with noise immunity when it is emitted and an air target is detected - carrier of RTR stations and active interference on this carrier the frequency of the probing signal f _i . In this case, the structure and parameters of the probing signal will not be recognized by the RTR station, and therefore, interference from the SAP side at a given carrier frequency f _i will not be performed.

Thus, the application of the present invention will allow due to simultaneous changes in the average power of the radar transmitter, the time of coherent signal accumulation in its receiver and the carrier frequency of the probing signal to always ensure noise immunity of the pulse-Doppler radar when operating on radiation and detecting an air target - carrier of RTR stations and active interference.

Information sources

1. Aviation radar systems and systems: a textbook for students and cadets of the Air Force / PI. Dudnik, G.S. Kondratenkov, B.G. Tatarsky, A.R. Ilchuk, A.A. Gerasimov. Ed. P.I. Angelica. - M .: ed. VVIA them. prof. NOT. Zhukovsky, 2006, pages 630 (formula (12.89), 639-641, figure 12.39 (analogue).

2. Belotserkovsky G. B. Fundamentals of radar and radar devices. - M .: “Owls. Radio ”, 1975, page 96, formula (4.8).

3. Bogdanov A.V., Antipov V.N., Zakomoldin D.V., Short S.S. The method of functioning of the pulse-Doppler airborne radar station when detecting an air target - the carrier of a radio intelligence station / Patent for invention No. 260,550 IPC G01S 13/52 (2006.01), Russia, application No. 2015154927, priority December 21, 2015, registered January 23, 2017. Bull No. 3 (prototype).

Claims (7)

The method of operation of a pulse-Doppler airborne radar station when detecting an air target - a carrier of radio intelligence stations and active interference, which consists in generating a high-frequency sequence of probe pulses at the initial carrier frequency f ₁ , their amplification in power, radiation in the direction of the air target - carrier of radio intelligence stations and active interference, reception, amplification, conversion of reflected signals to intermediate frequencies, their selection in range and additional Lehr frequency, the conversion of signals into digital form with their subsequent spectral analysis, while the range D _radar detection of air targets - carrier stations of electronic intelligence and active interference is determined by the expression

where R _bls - the average radiated power of the transmitter; T _kn - time of coherent signal accumulation in the receiver, equal to the time of irradiation of an air target - carrier of radio intelligence stations and active interference; G _radar - directional coefficient of the transmitting antenna; S _a is the effective area of the receiving antenna; σ _rtr is the effective reflection surface of an aerial target, the carrier of radio intelligence stations and active interference; α _n is the coefficient of signal energy loss during its processing; N _{0 is the} spectral density of the internal noise of the receiver; R ₀ is the ratio of the signal energy to the spectral density of noise, which ensures the detection with a given probability of an air target - carrier of radio intelligence stations and active interference, and, at each reception of a signal reflected from an air target - carrier of radio intelligence stations and active interference, measured value D _radar detection range compared with the maximum ELINT detection range value D _RTR station radiated airborne radar vysokochasto Nogo probe signal at the carrier frequency f _1, defined by the expression

where G _rtr is the directional coefficient of the receiving antenna of the radio intelligence station; λ _radar - wavelength of an airborne radar station; P _rtr is the maximum value of the sensitivity of the receiver of the radio intelligence station, when the condition

deciding that the secrecy-board radar station during its operation on the radiation provided and ELINT station does not detect or recognize the structure and parameters of the radiated airborne radar station signal on the original carrier frequency f _1, the average radiated power P _radar transmitter time irradiation target air - carrier stations ELINT and jamming and time T _Vol coherent signal acquisition in the receiver onboard radar will melt unchanged, characterized in that if the condition (3) is not satisfied, then simultaneously with the increase in n times, where n - an integer or fractional number greater than one, the irradiation time aerial target - carrier ELINT stations and jamming and time T _kn coherent signal accumulation in the receiver of the airborne radar station, by reducing by n times the average radiated power R _radar transmitter of the airborne radar station, they switch to another carrier frequency f _i , where i = 2, I; I is the total number of carrier frequencies of the probing signal until condition (3) is satisfied.

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