Method of protecting radio-electronic systems from interference

Abstract

FIELD: radio engineering.SUBSTANCE: invention can be used in the construction of radar systems (REE) in order to increase their protection against barrage interference. In the method of protection against interference, the allocated range of carrier frequencies of the REE is divided into N sub-ranges, the width of the gap between adjacent sub-ranges is set so that the spectrum of the barrage interference, the central frequency of which corresponds to the average value of the maximum and minimum carrier frequencies of the REE in the entire allocated range, does not fall in whole or in part into any of the sub-ranges, the change in the carrier frequency of the REE signals is carried out after the emission of each signal in the entire allocated range, the interference level is assessed before the emission of each REE signal at its carrier frequency.EFFECT: increased protection of radio electronic equipment operating under pseudo-random frequency hopping from barrage interference.1 cl

Description

[0001] The invention relates to the field of radio engineering and can be used in the construction of various radio-electronic (radar) systems in order to increase their protection against targeted and frequency-based interference.

[0002] The electronic countermeasures (ECM) system has two main operating modes: the "reconnaissance" mode and the "reconnaissance-suppression" mode [Military-technical training. Military-technical principles of constructing ECM systems and complexes. / / A.S. Osipov. - Krasnoyarsk.: Publishing center of the Library and Publishing Complex of the Siberian Federal University. 2013 - 344 p.].

[0003] In "Reconnaissance" mode, the ECCM system enters search mode. Signals from electronic systems (ES) operating in the monitored frequency range are fully processed and recorded. Upon termination of "Reconnaissance" mode and detection of ES of the specified type, the ECCM system switches to "Reconnaissance-Suppression" mode.

[0004] In the "reconnaissance-suppression" mode, the electronic warfare system operates cyclically. Upon detecting the operation of a given type of electronic warfare system, the electronic warfare system enters the "suppression" cycle. The "suppression" cycle alternates with a "pause" cycle. During the "pause" cycle, the electronic warfare system searches for signals and processes them similarly to the "reconnaissance" mode. If no operation of a given type of electronic warfare system is detected during the "pause" cycle, the electronic warfare system enters the "reconnaissance" mode.

[0005] Upon detection of the operation of a given type of electronic equipment on fixed carrier frequencies, the electronic countermeasures system switches to the creation of targeted frequency-based jamming: response jamming created simultaneously on all detected frequencies and having a spectrum consisting of bands comparable in width to the spectrum width of the signals being jammed and coinciding in position with the carrier frequencies of the signals being jammed.

[0006] Upon detection of a specified type of radio electronic device operating at carrier frequencies whose values ​​vary within a designated carrier frequency range according to a specific pattern, the electronic countermeasures system initiates a frequency-based jamming scheme, the spectrum of which covers the entire range of detected signals. The electronic countermeasures system determines the minimum and maximum carrier frequencies of the radio electronic device, calculates their average value, and uses this value as the center frequency of the jamming scheme.

[0007] A known method of protecting radio-electronic systems from interference consists of a stepwise change in the carrier frequency of the RES in a selected range of carrier frequencies according to a pseudo-random law that determines the order of changing the carrier frequencies [Interference immunity of radio communication systems with an expansion of the signal spectrum by the method of pseudo-random hopping of the operating frequency. / / V.I. Borisov. V.M. Zinchuk. A.E. Limarev, N.P. Mukhin. V.I. Shestopalov. - M.: Radio and communication, 2000. - 384 p.].

[0008] This method of protecting electronic systems from interference allows for a significant reduction in the effectiveness or elimination of the impact of targeted frequency-barrier interference, when the total width of the interference spectrum only slightly exceeds the allocated range of carrier frequencies (the total width of the spectrum of the suppressed signals).

[0009] If the electronic reconnaissance data shows that it is ineffective to create retaliatory targeted frequency-based jamming, the electronic warfare system switches to creating frequency-based jamming.

[0010] The central frequency of the barrage jamming corresponds to the average value of the maximum and minimum frequencies of the electronic countermeasure system; the maximum difference between the maximum and minimum frequencies of the barrage jamming (the spectrum of the barrage jamming) is determined by the technical capabilities of the electronic countermeasure system.

[0011] The disadvantage of this method is the lack of ability to provide protection against frequency-based interference.

[0012] A method for protecting radio-electronic systems from interference is known [Patent 2731129 RF, IPC H04B 15 / 00. Method for protection against interference / Varin A.P., Grigoriev S.I., Zolotukhin A.V. / / Inventions. - 2020. - N 25 dated 08 / 31 / 2020], selected as a prototype.

[0013] In the prototype method, the allocated range of radio electronic equipment carrier frequencies is divided into two sub-ranges.

[0014] They abruptly change the carrier frequencies of the radio-electronic equipment signals in a selected range of carrier frequencies according to a pseudo-random law, thereby ensuring protection of the radio-electronic equipment from targeted interference.

[0015] The radio electronic equipment operates by pseudo-randomly hopping carrier frequencies in the first sub-range.

[0016] The ELECTRONIC EMP system in the “reconnaissance” mode detects an ELECTRONIC EMP operating in the first sub-range, switches to the “reconnaissance-suppression” mode and creates a frequency-deficient jamming in the first sub-range.

[0017] The interference level in the gaps between the carrier frequencies of the first and second sub-bands is assessed. The assessment is performed using an additional receiving channel of the radio electronic system.

[0018] The radio electronic equipment switches from the carrier frequencies of the first sub-band to the carrier frequencies of the second sub-band if the interference level in the first sub-band reaches the specified interference threshold level in the intervals between the operating frequencies of the first sub-band, and the interference level in the second sub-band is less than the specified interference threshold level in the intervals between the operating frequencies of the second sub-band.

[0019] If no RES operation is detected in the next “pause” cycle in the first sub-range, the RES system switches to the “reconnaissance” mode.

[0020] Return the operation of the radio electronic equipment to the carrier frequencies of the first sub-range when the interference level decreases below the specified threshold level in the intervals between the operating frequencies of the first sub-range.

[0021] Then the process is repeated cyclically.

[0022] Modern ELECTRONIC WARfare systems have the ability to simultaneously operate in multiple frequency ranges (sub-ranges). The AN / ALQ-99E ELECTRONIC WARfare system operates in multiple frequency ranges (sub-ranges), has up to 8 units, each of which includes a transmitting / receiving unit (TRU) and an antenna-feeder system (AFS), and can simultaneously suppress up to 16 ELECTRONIC WARfare systems [Electronic Warfare in the US Armed Forces. / / M.R. Mikhailov. - St. Petersburg. 2018. - 132 p.] and can simultaneously jam both sub-ranges of ELECTRONIC WARfare systems operating in accordance with the prototype method.

[0023] The disadvantage of the prototype method is the possibility of suppression by radio electronic equipment (RE) barrier interference.

[0024] The technical result of the proposed invention is to increase the protection of radio electronic equipment operating in a mode with pseudo-random frequency hopping from frequency-blocking interference.

[0025] The technical result is achieved in that in the method for protecting radio-electronic systems from interference, which consists in dividing the allocated range of carrier frequencies of the radio-electronic system into sub-ranges, in abruptly changing the carrier frequency of the signals of the radio-electronic system according to a pseudo-random law, assessing the level of interference, switching the radio-electronic system from a carrier frequency, the level of interference at which exceeds a given threshold level, to a carrier frequency at which the level of interference is below a given threshold level, the allocated range of carrier frequencies of the radio-electronic system is divided into N sub-ranges, where N≥3, the width of the gap between adjacent sub-ranges - the frequency difference between the extreme carrier frequencies of adjacent sub-ranges - is set to be no less than the difference between the maximum and minimum frequencies of the barrage interference - the spectrum of the barrage interference, the width of the gap between adjacent sub-ranges is set so that the spectrum of the barrage interference,the central frequency of which corresponds to the average value of the maximum and minimum carrier frequencies of the electronic system in the entire allocated range of carrier frequencies of the electronic system, does not fall in whole or in part into any of the sub-ranges, the abrupt change in the carrier frequency of the signals of the electronic system is carried out after the emission of each signal of the electronic system in the entire allocated range of carrier frequencies, the assessment of the interference level is carried out before the emission of each signal of the electronic system at its carrier frequency.

[0026] The proposed method for protecting radio-electronic systems from interference is implemented as follows.

[0027] Divide the allocated range of radio electronic equipment carrier frequencies into N sub-ranges, where N≥3.

[0028] Sets the width of the gap between adjacent sub-ranges - the frequency difference between the extreme carrier frequencies of adjacent sub-ranges - not less than the difference between the maximum and minimum frequencies of the barrage interference - the spectrum of the barrage interference.

[0029] Set the width of the gap between adjacent sub-ranges - the frequency difference between the extreme carrier frequencies of adjacent sub-ranges - so that the spectrum of the barrage interference, the central frequency of which corresponds to the average value of the maximum and minimum carrier frequencies of the radio equipment in the entire allocated range of radio equipment carrier frequencies, does not fall entirely or partially into any of the sub-ranges.

[0030] They abruptly change the carrier frequencies of the radio-electronic equipment signals in a selected range of carrier frequencies according to a pseudo-random law, thereby ensuring protection of the radio-electronic equipment from targeted interference.

[0031] They produce a stepwise change in the carrier frequency of the radio electronic signals after the emission of each radio electronic signal in the entire allocated range of carrier frequencies, and each radio electronic signal can be either a phase-shift keyed signal or a pulse burst.

[0032] Evaluate the interference level. The interference level is assessed before each radio-electronic means (REM) signal is emitted at its carrier frequency.

[0033] Switch the radio electronic equipment from a carrier frequency at which the interference level exceeds the specified threshold level to a carrier frequency at which the interference level is below the specified threshold level.

[0034] Switching is performed as follows.

[0035] The carrier frequency of the radio-electronic means (REM) signals is hopped according to a pseudo-random law and the interference level at this carrier frequency is assessed. If the interference level at this carrier frequency is below a specified threshold, the REM emits a signal; if the interference level at this carrier frequency is above a specified threshold, the REM hops the carrier frequency of the signals.

[0036] Changing the carrier frequencies in the allocated range of carrier frequencies according to a pseudo-random law is carried out until the end of the operation of the radio electronic means.

[0037] Let us consider the operation of the proposed method for protecting electronic systems from interference using the example of a radar system operating in three carrier frequency sub-bands with phase-shift keyed radiated signals in the C-frequency range (4.0 GHz - 8.0 GHz), when countered by an electronic countermeasure system. The spectrum of the barrage interference is 500 MHz.

[0038] To enable operation in three sub-bands, the radar system, in addition to the protection control unit, will include three functionally identical channels, each containing a transceiver, an antenna-feeder system, and a computing unit. Each channel ensures operation of the radar system in its own carrier frequency sub-band. Three channels ensure operation of the radar system in all carrier frequency sub-bands. Generally, the number of channels (the number of sub-bands) is limited by the size, weight, and power constraints imposed on the radar system.

[0039] Let's consider one channel of a radar system.

[0040] The transceiver of the radar system generates a radiated signal with the tuning of the carrier frequency of signals according to a pseudo-random law and phase manipulation from signal to signal, ensures the separation of the received signal into quadrature components and contains a signal generator, a transmitter and a receiver.

[0041] The signal generator of the transceiver is based on a voltage-controlled oscillator and a frequency synthesizer. The frequency synthesizer tunes the voltage-controlled oscillator, generating a carrier frequency at one of the m i frequencies within a given frequency subrange, where i ranges from 1 to M (the carrier frequency number in the channel). The frequency synthesizer is controlled by the radar system control unit.

[0042] The transmitter of the transceiver device is based on a two-level (0 / π) phase modulator, a power amplifier and an adjustable attenuator that regulates the output power level of the transmitter, ensuring increased stealth of the radar system.

[0043] The receiver of the transceiver device is made on the basis of:

[0044] - input power limiter, designed to protect the receiver from external powerful interference;

[0045] - receiver switch, designed to lock the receiver during the emission of a phase-shift keyed signal;

[0046] - a band-pass filter matched to the frequency band of a given sub-range, designed to protect the receiver from interfering signals outside of a given frequency sub-range;

[0047] - quadrature mixer.

[0048] The antenna-feeder system of the radar system ensures the formation of the required radiation pattern, the emission of a phase-shift keyed signal, and the reception of the reflected signal in a given frequency sub-band. The antenna-feeder system also provides additional protection for the transceiver receiver from interfering signals outside the given frequency sub-band.

[0049] The radar system's computing device provides control over the channel operation and digital processing of received reflected signals.

[0050] The operation of all three channels is controlled by the radar system control unit.

[0051] Let's consider the operation of a radar system.

[0052] The allocated range of carrier frequencies is divided into three sub-ranges: the first is (4.0-4.2) GHz, the second is (4.8-5.0) GHz, the third is (7.0-7.2) GHz, thereby ensuring that the following conditions are met:

[0053] - the width of the gap between adjacent sub-ranges is set to be no less than the spectrum of the barrage interference;

[0054] - the width of the gap between adjacent sub-ranges is set so that the spectrum of the barrage interference, the central frequency of which corresponds to the average value of the maximum and minimum frequencies of the RES in the entire allocated range of carrier frequencies of the radar system (5.6 GHz), does not fall into any of the sub-ranges (5.35 GHz - 5.85 GHz).

[0055] In each channel of the radar system, it is possible to emit a phase-shift keyed signal on one of the m iy carrier frequencies within the frequency subrange of a given channel, where i is from 1 to M (the carrier frequency number in the channel), and y is from 1 to 3 (the channel number). Then, the radar system can emit a phase-shift keyed signal across the entire allocated carrier frequency range on one of the carrier frequencies, each of which is assigned its own number m iv .

[0056] Before emitting each phase-shift keyed signal, the radar system control unit determines the carrier frequency number m according to a pseudo-random law. iy , on which the phase-shift keyed signal will be emitted, thereby determining the channel number y, which will emit the signal at a given moment in time.

[0057] After determining the carrier frequency and channel numbers, the receiver of this channel evaluates the interference level on the carrier frequency m iy The receiver of this channel outputs the evaluation results to the control unit of the radar system.

[0058] If the interference level at the carrier frequency is m iy below a specified threshold level, the radar system control unit issues a command to emit a phase-shift keyed signal at the carrier frequency m iyAfter receiving the reflected signal (determined by the clock frequency of the phase-shift keyed signals), the radar system control unit determines the number of the next carrier frequency according to a pseudo-random law.

[0059] Carrier Frequency Interference Level m iy cannot be higher than the specified threshold level, since the spectrum of the barrage interference (5.35 GHz - 5.85 GHz) does not fall into any of the sub-ranges.

[0060] If the EW system has switched to creating targeted and barrage frequency interference, the interference level at the carrier frequency is m iy may be higher than the specified threshold level in the event of a random coincidence of the carrier frequency m iy with the frequency of the target-barrier interference.

[0061] In this case, the radar system control unit does not issue commands to emit a phase-shift keyed signal at the carrier frequency m iy and, according to a pseudo-random law, determines the number of the next carrier frequency.

[0062] Changing the carrier frequencies in the allocated range of carrier frequencies according to a pseudo-random law is carried out until the end of the radar system operation.

[0063] Thus, the proposed invention, in comparison with the prototype method, makes it possible to increase the protection of the electronic equipment from frequency-based interference created by modern electronic countermeasure systems.

Claims

A method for protecting radio-electronic systems from interference, which consists in dividing the allocated range of carrier frequencies of the radio-electronic system into sub-ranges, in abruptly changing the carrier frequency of the signals of the radio-electronic system according to a pseudo-random law, assessing the level of interference, switching the radio-electronic system from a carrier frequency, the level of interference at which exceeds a given threshold level, to a carrier frequency at which the level of interference is below a given threshold level, characterized in that the allocated range of carrier frequencies of the radio-electronic system is divided into N sub-ranges, where N ~ 3, the width of the gap between adjacent sub-ranges - the frequency difference between the extreme carrier frequencies of adjacent sub-ranges - is set to be no less than the difference between the maximum and minimum frequencies of the barrage interference - the spectrum of the barrage interference, the width of the gap between adjacent sub-ranges is set so that the spectrum of the barrage interference,the central frequency of which corresponds to the average value of the maximum and minimum carrier frequencies of the electronic system in the entire allocated range of carrier frequencies of the electronic system, does not fall in whole or in part into any of the sub-ranges, the abrupt change in the carrier frequency of the signals of the electronic system is carried out after the emission of each signal of the electronic system in the entire allocated range of carrier frequencies, the assessment of the interference level is carried out before the emission of each signal of the electronic system at its carrier frequency.