RU2608551C1 - Pulse-doppler airborne radar station operating method during detecting of aerial target, radio reconnaissance station carrier - Google Patents

Abstract

FIELD: radars.

SUBSTANCE: invention relates to radars and can be used during aerial target detection. Method consists in generation of probing pulses high-frequency sequence, their amplification by power, emitting in aerial target direction, radio reconnaissance station (RRS) carrier, receiving, amplification, conversion of reflected signals to intermediate frequencies, their selection by range and Doppler frequency, conversion of signals into digital form with their further spectral analysis, during each reception of signal reflected from aerial target, RRS station carrier, measured detection range D_ARS value is compared with maximum detection range D_RRS value of ARS emitted signal by RRS station, is meeting condition D_ARS>D_RRS making decision on, that ARS security at its operation on radiation is provided and RRS station does not detect ARS emitted signal, besides, ARS transmitter average radiated power, exposure time of aerial target, RRS station carrier and signal coherent accumulation time in ARS receiver remain unchanged, otherwise simultaneously increasing in n times, where n is integer or fractional number, larger than one, exposure time of aerial target, RRS station carrier and signal coherent accumulation time in ARS receiver and reducing ARS transmitter average radiated power in n times until, condition D_ARS> D_RRS, which testifies on provision of ARS secure operation on radiation.

EFFECT: technical result is provision of pulse-Doppler airborne radar station (ARS) secure operation on radiation during detecting of aerial target, radio reconnaissance station (RRS) carrier.

1 cl, 2 dwg

Description

The invention relates to the field of radar and can be used to ensure the secrecy of the work of the pulse-Doppler airborne radar station (radar) on radiation when an air target is detected - the carrier of the radio intelligence station (RTR).

A known method of functioning of a coherent-pulse radar device, which consists in generating using a master signal generator, converting it into a high-frequency signal by multiplying its frequency, amplifying its power and radiation into space, receiving a radar signal reflected from an air target, converting it to an intermediate frequency, amplification and phase detection for subsequent processing in the receiving path of the radar [1].

The disadvantage of this method of operation of a coherent-pulse radar device is the inability to use it to provide stealth radar when detecting an air target equipped with an RTR station.

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 [2].

The disadvantage of this method is the impossibility of using it to ensure the secrecy of the radar when it detects an air target, which may be the carrier of the RTR station. This is due to the fact that, on the one hand, the range D of the _{radar for} detecting the target carrier of the RTR station using the 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 station RTR;

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 station;

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 - the ratio of the signal energy to the spectral density of the noise, which ensures the detection of an air target - carrier station RTR with a given probability.

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.

There are two possible situations. The first situation is when the detection range of the radar radiated signal by the RTR station is greater than or equal to the detection range of the radar of the carrier of the RTR station, i.e. D _PTP ≥D _radar . The second situation is when the detection range of the radar station of the air target carrier of the RTR station exceeds the detection range of the radiated radar station of the probing signal by the RTR station, i.e. D _radar > D _PTP . Therefore, in the first case, the secrecy of the radar is not provided, and in the second it is provided.

Therefore, to ensure the stealth of the radar’s operation on radiation when an air target is detected - the carrier of the RTR station, it is necessary to constantly monitor and maintain the condition

The purpose of the invention is to ensure the secrecy of the functioning of the pulse-Doppler airborne radar station upon radiation when an air target is detected - the carrier of the radio intelligence station.

This goal is achieved by the fact that in the method of functioning of the pulse-Doppler radar upon detection of an air target - carrier of the RTR station, which consists in the formation of a high-frequency sequence of probe pulses, their amplification in power, radiation in the direction of the air target - carrier of the RTR station, reception, amplification, conversion reflected signals at intermediate frequencies, their selection in range and Doppler frequency, the conversion of signals into digital form with their subsequent spectral analysis, while the D _radar detection range of the aerial target - carrier of the RTR station is determined by the expression (1), in addition, at each reception of the signal reflected from the carrier of the RTR station, the measured value of the D _radar detection range D is compared with the maximum value of the detection range D _{PTP of} the radiated radar radar RTR station determined by the expression (2), when condition (3) is fulfilled, a decision is made that the secrecy of the radar station is ensured when it is working on radiation and the RTR station does not detect the radiated radar signal, the average radiated power of the transmitter, the time of irradiation of the air target - carrier of the RTR station and the time of coherent signal accumulation in the radar receiver remain unchanged, if condition (3) is not met, then they increase n times, where n is an integer or fractional number greater units, the time of irradiation of an air target - carrier of the RTR station and the time of coherent signal accumulation in the radar receiver and reduce by n times the average radiated power of the radar transmitter until condition (3) is fulfilled, which is evidenced by t of ensuring secrecy of the work on the radar radiation.

New features with significant differences are:

1. Decision-making on ensuring the secrecy of the operation of a pulse-Doppler radar upon radiation when an air target is detected by the carrier of an RTR station based on an analysis of the result of comparing the measured value of the detection range D _{radar of an} air target as a carrier of an RTR station with a maximum value of the detection range D _PTP by an RTR radiated radar station high-frequency sounding signal.

2. A simultaneous increase in n times, where n is an integer or fractional number, greater than one, of the time of exposure of the carrier of the RTR station and the time of coherent signal accumulation in the radar receiver and a decrease of n times the average radiated power of the radar transmitter to satisfy condition (3), which indicates the secrecy of the radar on the radiation.

These signs have significant differences, as in the known methods are not found.

The use of new features will make it possible to monitor and ensure the secrecy of the radar’s operation when it detects an air target — the carrier of the RTR station.

Figures 1 and 2 are respectively a block diagram and graphs explaining the proposed method of functioning of a pulse-Doppler radar upon detection of an air target - carrier of the RTR station.

The method of functioning of the pulse-Doppler radar upon detection of an air target - carrier of the RTR station is implemented as follows (Figure 1).

Using the master oscillator 1, synchronizer 2 and modulator 3, high-frequency sequences of probe pulses are generated, which are amplified in a high-frequency power amplifier 4 with a controlled gain and through antenna switch 5, antenna 6 is emitted in the direction of the air target - carrier of the RTR station. The signals reflected from the air target - carrier of the RTR station 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 7, converted into intermediate frequencies in the conversion path 8, and selected in range in the range selector 9 using the selector pulses arriving at its input from the output of the synchronizer 2, and are also selected by the Doppler frequency in the Converter 10, the inputs of which receive the values of the orientation angles of the radiation pattern ntenny in the vertical and horizontal planes with a goniometric output channel (not shown in the diagram) and the value of a private BRLS carrier speed output from 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 13, the _radar detection range D of the _{radar for} detecting the radar of an air target - carrier of the RTR station is compared, which is compared in the analyzer 15 with the maximum distance D _{PTP of the} detection by the RTR station of the radiated radar of the probe signal calculated by the RTP station in accordance with formula (2).

When condition (3) is fulfilled, the analyzer 15 makes a decision that the radar stealth during its work on radiation when an air target is detected - the carrier of the RTR station is provided. At the same time, signals are generated at the first, second, and third outputs of the analyzer 15, which prohibit changes in the time of coherent signal accumulation (equivalent to the passband of one bin of the FFT algorithm), respectively, in the FFT block 12, and the time of irradiation of an air target — the carrier of the RTR station, which is controlled by the antenna control system 16, and the radiated average transmitter power, which is controlled in the high-frequency power amplifier 4.

If the condition (3) is not fulfilled, the analyzer 15 makes a decision that the stealth of the radar when it is working on radiation when it detects an air target - the carrier of the RTR station is not provided. At the same time, signals are generated at the first, second, and third outputs of the analyzer 15, which are permissive for increasing by a factor of n, where n is an integer or fractional number greater than one, respectively, of the time of coherent signal accumulation in the FFT unit 12 by increasing the number of samples of the FFT procedure at a constant the sampling frequency of the signal in block 11 and the exposure time of the air target carrier of the RTR station by controlling the radiation pattern of the radar antenna using the antenna control system 16 so that the residence time I of the beam of the radiation pattern would be at the angular position at which the aerial target was detected - the carrier of the RTR station, it would be equal to the coherent accumulation time of the signal in block 12 of the FFT, as well as a resolving signal to reduce by n times the radiated average power of the radar transmitter by decreasing the coefficient amplification in the amplifier 4 power high frequency.

Figure 2 shows the results of calculating the dependences of the _radar ranges D of the detection of radar of an air target — carrier of an RTR station on the average radiated power of the _{radar of the} transmitter at a coherent accumulation time of 10 ms and 20 ms (dependences 1 and 2, respectively) and the range of D _PTP detection of radiated radar by the RTR station signal calculated according to formulas (1) and (2), respectively, with the following typical initial data.

To calculate the range D _radar detection (formula (1)) radar air target carrier station RTR: G _radar = 6200; S _a = 0.79 m ² ; σ _rtr = 9 m ² ; α _p = 1; Ν ₀ = 4 10 ^-21 W / Hz; R ₀ = 13 dB.

To calculate the range D _PTP detection (formula (2)) station RTR radiated radar signal: G _RTR = 80; λ _radar = 4 cm; P _rtr = -80 dB.

From the above graphs it follows that, for example, with an average radiated power of the radar transmitter R _radar = 690 W and with the initially adopted coherent accumulation time T _kn = 10 ms (dependence 1), the detection range of the air target carrier of the RTR station is D _radar = 490 km , while for the same radiated average power of the radar transmitter R _radar = 690 W, the detection range of the radar radar radiated by the RTR station (dependence 3) is D _PTP = 580 km, i.e. condition (3) is not fulfilled, which indicates that the secrecy of the radar when the air target is detected - the carrier of the RTR station is not provided.

If now simultaneously increase by 2 times the time of coherent signal accumulation up to 20 ms (dependence 2), equal to the time of irradiation of an air target - carrier of the RTR station, and reduce by 2 times the average radiated power of the radar transmitter to R _radar = 345 W, then the detection range of air the target of the carrier of the RTR station will continue to be D _radar station = 490 km, and the detection range of the radiated radar station signal (dependence 3) by the RTR station will already be D _PTP = 410 km, i.e. in this case, condition (3) is fulfilled, which indicates that by simultaneously increasing the coherent signal accumulation time and the exposure time of the airborne target - the carrier of the RTR station and reducing the average radiated power of the radar transmitter, secrecy of the radar operation upon radiation is detected when a target of the station carrier is detected RTR.

Thus, the application of the present invention will ensure the secrecy of the functioning of the pulse-Doppler radar upon radiation upon detection of an air target - carrier station RTR.

Information sources

1. Aviation radar systems and systems: A textbook for students and cadets of the Air Force. / P.I. 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, p. 527-528, fig. 11.4 (analog).

2. Aviation radar systems and systems: A textbook for students and cadets of the Air Force. / P.I. 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, p. 630 (formula (12.89)), p. 639-641, fig. 12.39 (prototype).

3. Belotserkovsky GB Basics of radar and radar devices. - M .: Owls. Radio, 1975, p. 96, formula (4.8).

Claims (7)

The method of operation of a pulse-Doppler airborne radar station when detecting an air target - a carrier of a radio intelligence station, which consists in generating a high-frequency sequence of probe pulses, amplifying them in power, radiation in the direction of an air target - carrier of a radio intelligence station, receiving, amplifying, converting reflected signals to intermediate frequencies, their selection in range and Doppler frequency, the conversion of signals into digital form with the following their spectral analysis, while the D range of the _{radar for} detecting an air target - the carrier of a radio intelligence station 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 a radio intelligence station; 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 - carrier of a radio intelligence station; 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 signal energy to noise spectral density, which ensures the detection of an aerial target - carrier of a radio intelligence station with a given probability, characterized in that at each reception of a signal reflected from an air target - carrier of a radio intelligence reconnaissance device, the measured value of the _radar detection range D is compared maximum detection range value D _RTR station ELINT radiated airborne radar with a high-frequency probe I drove 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

decide that the airborne radar station's secrecy is ensured during radiation and the radio intelligence station does not detect the signal radiated by the airborne radar station, while the average radiated power P _radar , the time of irradiation of the air target carrier of the radio intelligence station and the time T _kn coherent signal accumulations in the receiver of the airborne radar station remain unchanged, if condition (3) is not met, then at the same time increase n times, where n is an integer or other obnoe number greater than one, the irradiation aerial target - carrier station ELINT and time T _Vol coherent signal acquisition in the receiver on-board radar system and reduces in n times the average radiated power P _radar transmitter on-board radar system as long as there is no condition (3), which indicates the secrecy of the operation of the airborne radar station for radiation.

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