RU1841295C - Active jamming transmitter - Google Patents

Abstract

FIELD: radar and radio countermeasures.

SUBSTANCE: invention relates to the field of radio interference with enemy technical means. To disrupt the missile guidance and exclude the timely submission of a command to detonate the missile warhead, an interference signal is generated that masks only the range section directly adjacent to the protected aircraft at the responder frequency. This is achieved by receiving radar signals from target and missile sighting radars, as well as signals from the responder, and processing the received information in the threat assessment unit with the formation of a leading pulse to open the terminal amplifier that amplifies the signals of the missile responder stored in frequency.

EFFECT: provided is high peak interference power while reducing the power consumption from primary power sources.

1 cl, 2 dwg

Description

This proposal relates to the field of radio countermeasures.

In the anti-aircraft defense system, anti-aircraft guided missile systems with command control (the Nike-Hercules SAM complex) are widely used.

The radio-technical part of the complex consists of radars for sighting the target and the missile according to the signals of the on-board transponder, which provide information on the current coordinates of the target and the missile, which is necessary to guide the missile to the target and form a command to undermine the missile warhead.

The exclusion of missile guidance and timely delivery of a command to detonate is possible by suppressing the missile sighting channel according to the signals of the transponder, since information about the range to the missile is necessary for the formation of these commands. The difficulty of suppressing the transponder signal reception channel in the missile sighting radar is due to the need for interference on most of the missile's flight path through the side lobes of the missile sighting radar receiving antenna, as well as the stealth of the transponder's operating frequency. The transponder operates at lettered frequencies located in the operating range of the missile sighting radar. The carrier frequency of the transponder is set before the missile is launched and does not change in flight.

Known transmitters for the formation of interference on this channel (Fig. 1). They consist of a receiving (1) and transmitting (5) antenna, a reconnaissance receiver 2, a frequency memory device 3 and a power amplifier 4. The carrier frequency of the transponder pulsed radio signal received by the reconnaissance receiver 2 is stored in the frequency memory device 3, and the received continuous signal modulated by noise , is amplified to the required power level by amplifier 4.

When the interference masks the signal of the transponder, the radar of the sighting of the missile begins to take direction in the corners instead of the signals of the transponder of the missile, the aircraft emitting interference. As a result, instead of the angular coordinates of the rocket, the coordinates of the aircraft come from the missile sighting radar to the computer, i.e. the conditions for combining a rocket with an aircraft are simulated. At the same time, current information about the range to the missile is stopped from the missile sighting radar to the computer, and commands to control the missile will not be received, and the lack of range to the missile will introduce an error in determining the moment the detonation command is given.

The interference power required to suppress the missile sighting channel by such a transmitter can be determined from the following expression

- требуемое превышение помехи для обеспечения маскировки сигнала ответчика;where

- the required excess interference to ensure the masking of the transponder signal;

- излучаемая мощность ответчика;

- transponder radiated power;

- уровень боковых лепестков приемной антенны радиолокатора визирования ракеты;

- the level of the side lobes of the receiving antenna of the missile sighting radar;

- расстояние от цели до радиолокатора;

- distance from the target to the radar;

- расстояние от ракеты до радиолокатора.

- distance from the missile to the radar.

= 10 дБ,

= 40 дБВт,

= 20 дБ, то для срыва сопровождения сигналов ответчика потребуется эквивалентная непрерывная мощность около 80 дБВт. Реализовать на самолете такой уровень мощности непрерывной шумовой помехи практически невозможно.If accept

= 10 dB,

= 40 dBW,

= 20 dB, then an equivalent continuous power of about 80 dBW is required to disrupt the tracking of the transponder signals. It is practically impossible to implement such a power level of continuous noise interference on an aircraft.

In this regard, a jamming transmitter is proposed, which makes it possible to interfere with the missile sighting radar according to the signals of the onboard transponder at a lower average output power of the terminal amplifier. To this end, they are limited to effective suppression of the response channel not of the entire range of the radar station - the target, but only of its part directly adjacent to the protected aircraft.

The stated essence of the invention is illustrated by the drawing, where it is shown in Fig. 1 is a block diagram of a noise interference transmitter, where 1 is a receiving antenna; 2 - signal receiver onboard transponder; 3 - frequency storage device; 4 - modulator - power amplifier of microwave oscillations; 5 - transmitting antenna.

In FIG. 2 is a block diagram of the proposed active jamming transmitter for a missile sighting radar based on the transponder's signals, where 1, 2, 3, 4, 5 is the same as for FIG. 1, and 6 is a signal splitter; 7 - target tracking radar signal receiver; 8 - threshold device for comparing the amplitudes and time of receiving radio pulses; 9 - receiver of signals from the transmitter of the missile tracking radar; 10 - threat assessment unit; 11 - shaper "leading" interference pulse.

. Кроме того, самолет, по мере сближения с ракетой, входит в основной луч приемной антенны РЛС визирования ракеты, что позволяет соответственно уменьшить потери сигнала помехи еще примерно 10÷20 дБ.The minimum distance of the missile - the target at which the missile sighting radar is redirected according to the signals of the defendant to obtain the required miss or error at the moment the detonation command is issued, depends on the maneuverability of the aircraft, its speed and flight altitude, the removal of the aircraft from the complex, and will approximately be about 5 ÷10 km. In this case, the gain in the interference power level can be charged by about 10 dB, due to the fact that the coefficient

. In addition, the aircraft, as it approaches the missile, enters the main beam of the receiving antenna of the missile sighting radar, which makes it possible to correspondingly reduce the loss of the interference signal by about 10–20 dB.

Thus, if these conditions are realized, then the required power of targeted interference to suppress the missile channel will be about 50÷60 dBW. In the presence of a directionally induced interference transmitter antenna (PAR) with a gain of 20 dB, the required power of the final amplifier will be about 30÷40 dBW. Given that effective masking of the transponder missile signal is not carried out at the entire range of the aircraft from the radar, it becomes possible to use pulsed interference radiation, appropriately synchronized by the probing signal of the transponder.

The duty cycle of such noise interference is equal to the ratio of the duration of the repetition period of the responder's request pulses and the interference pulse. The duration of the interference pulse must be sufficient for a day in order to mask the range section in front of the circuit pulse over the response channel that exceeds the permissible minimum distance of the missile to the target. Approximately the duty cycle of the interference can be taken equal to 10. Therefore, the average power of the transmitter of aimed interference to suppress the missile channel will be 20÷30 dBW. As the final stage of such a jamming transmitter, for example, an amplitron and other EVPs with high efficiency can be used.

Synchronization of the transmitter operation can be carried out by receiving the signals of the missile's sighting radar (or the missile's transponder) with the subsequent formation of a modulating pulse of a "leading" noise signal. This video pulse opens the output stage of the power amplifier of the jamming transmitter, the high-frequency input of which receives a modulated signal from the frequency storage device.

Consider the possibility of determining the carrier frequency of the transponder using aircraft equipment. Taking into account the energy potential of the transponder (40 dBW), the level of the side lobes of the transmitting antenna of the transponder is 20 dB, the maximum range of receiving signals from the transponder is 150 km and the gain of the receiving antenna of the aircraft reconnaissance receiver is 10 dB, we get that the required sensitivity of the reconnaissance receiver should be about 130 dBW. This is if it is necessary to determine the frequency of the transponder when the missile is at maximum range.

At a shorter range, the required sensitivity will be lower.

Since the transponder is launched by the missile sighting radar signals, the detection of the transponder pulse signals should be carried out in the time interval between the time of receipt of the probing signal of the missile sighting radar and the moment the transponder signal is received along the radar-missile-target path. As the missile approaches the target, this difference between the moments of receipt by the aircraft of the radar pulse of the sighting of the missile and the transponder decreases, which can be used to estimate the deviation of the missile from the missile's flight path along the beam. If this difference is close to zero during the flight of the missile, then this may serve as an indication of the fact that the missile is guided by the three-point method or along the beam.

The block diagram of the proposed jamming transmitter for the missile channel is shown in fig. 2.

The interference transmitter consists of a receiving and transmitting antenna (1 and 5, respectively), a high-frequency signal splitter 6, radio signal receivers of a target sighting radar 7, a missile sighting radar receiver 9 and a transponder 2, a threshold device for comparing the amplitudes and time of receiving radio pulses 8 connected to the outputs of the receivers 2, 7 and 9.

Information from the output of the comparison device 8 is fed to the threat assessment unit 10. The signal receiver of the missile sighting radar transmitter 9 is connected to the shaper of the "leading" interference pulse - 11, which modulates the transponder's stored signal in the final amplifier 4.

The jamming transmitter works as follows.

The signal of the target sighting radar through the receiving antenna 1, the splitter 5 enters the signal receiver of the target sighting radar 7.

The inclusion of the missile sighting radar is determined by another receiver 9, the video signal of which is used to form in 11 a modulating "leading" noise interference pulse. Simultaneously in the circuit for comparing the amplitudes of the signals of the receivers 3, 7 and 9 and the time of their reception 8. The level of this signal is measured and compared with a certain weight with the level of the received signal of the target sighting radar. The result of the comparison enters the threat assessment block 10. The signals of the missile transponder are received by the antenna 1, amplified and fed into the frequency storage device. In this device, the signal stored in frequency is endowed with an appropriate noise or pulse modulation and is emitted through a pulse final power amplifier in the direction of the location of the missile sighting radar. Measured in scheme 8, the difference in the moments of reception of the pulses of the defendant and the missile sighting radar is used in the threat assessment block on the 10th day of determining the "dangerous" situation.

Claims (1)

An active jammer transmitter containing a serially connected receiving antenna, a reconnaissance receiver for signals from an airborne anti-aircraft missile transponder, a frequency memory device, a power modulator-amplifier, an output signal evaluation unit and a transmitting antenna, characterized in that, in order to increase the efficiency of protecting an object from an anti-aircraft missile missiles, a signal splitter is additionally introduced into it, connected between the receiving antenna and the reconnaissance receiver, receivers of signals of radar tracking the target and the missile, the inputs of which are connected to the second and third outputs of the signal splitter, and the outputs of all three receivers are connected to three inputs of the amplitude comparison device and the time of reception of radio pulses, the outputs of which are connected through the output signal evaluation unit to the second input of the power modulator-amplifier, the second output of the missile tracking radar signal receiver, in addition, through the generator of the leading interference pulse is connected to the The secondary input of the power amplifier modulator.

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