RU2583050C1 - Method of identifying false path formed by synchronous repeater jamming - Google Patents

Abstract

FIELD: radio.

SUBSTANCE: invention relates to radar and can be used in radar stations for protection from synchronous repeater jamming. Said technical result is achieved by that in method of identifying false trajectory formed with synchronous repeater jamming, based on a tracking strobe recognisable trajectory and detection therein of marks, emitting a probing signal of reduced power - false probe, where signal reflected from real target will be lower than detection threshold and recognisable trajectory feature “false” if a mark is detected in gate.

EFFECT: technical result is identification of false trajectory formed when tracking marks from synchronous repeater jamming in entire coverage area.

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Description

The claimed technical solution relates to the field of radar and can be used in radar stations (radar) to protect against synchronous response interference.

Big problems to the operation of the radar create pulse response interference and, above all, synchronous response interference. The installer of this interference repeatedly re-emits an amplified copy of the probe signal with a level independent of the probe signal level. As a result of its action, false detection of targets occurs, since the received signals of synchronous response interference do not differ from signals reflected from real targets. Interference is especially effective when it simulates the movement of a target with a speed set by the interference designer. As a result, a false trajectory is formed that does not differ from the trajectories of real targets [Protection from interference. Ed. M.V. Maksimova, M., Sovetskoe Radio, 1976, p. 61], which leads to an overload of signal processing devices in the radar and makes it impossible to distinguish trajectories of real targets. Therefore, the problem of recognizing a false trajectory is relevant.

The closest known method for recognizing a false trajectory (track) generated by a synchronous response interference [RF Patent No. 2534754], based on the installation of the strobe of the possible position of the marks of the trajectory being checked and detection of marks in them. The disadvantage of this method is the limitation of its scope: the method works only in the space between the jammer and the radar, i.e. it does not recognize a false trajectory located in the space behind the jammer.

Thus, the technical result (the problem being solved) is the recognition of a false trajectory, which is formed when tracking marks from synchronous response interference in the entire radar viewing area.

The specified technical result is achieved by the fact that in the method for recognizing a false trajectory generated by a synchronous response interference, based on the installation of strobe tracking the recognizable trajectory and detecting marks in them, according to the invention a probing signal of reduced power is emitted - a false probe, in which the reflected signal from the real target will be below the detection threshold and set the recognizable trajectory sign "false" if a strobe is detected.

The specified technical result is also achieved by the fact that the power of the false probe is determined from the mathematical expression

where R _{L. probe} - the power of the false probe;

P _probe is the power of the probing signal;

u ₀ is the detection threshold;

u is the measured amplitude of the signal received in the tracking strobe of the checked trajectory when the probe signal is emitted.

The specified technical result is also achieved by the fact that the power of the false probe is set by reducing the antenna gain in the inspected direction due to the deviation of the beam from this direction for the duration of the radiation of the false probe.

The essence of the proposed method is that to detect a false trajectory, reduce the power of the probe signal (emit a false probe), while the director of synchronous response interference, located at any distance, even at the maximum, unattainable for weapons (this is the most favorable position for the jammer and the most difficult for the radar), to suppress the radar emits an amplified copy of this signal, which will exceed the detection threshold. Since the power level of the false probe is set such that when it is reflected from a real target, the signal level would be below the detection threshold, then, after the radiation of the false probe, only the response noise can exceed the detection threshold. This is a sign on the basis of which a false sign is established for a recognizable trajectory.

The false probe level is set based on the following. When a false probe is emitted, the level of the reflected signal from a real target with a certain probability (equal to the allowable probability of erroneous recognition of a false path) should not exceed the detection threshold. If this excess occurs during the emission of a false probe, then the trajectory of the real target will be taken as a false one. The probability of such an event should not exceed the specified permissible. Based on this, the power of the false probe can be determined from the expression

where R _{L. probe} - the power of the false probe;

P _probe is the power of the probing signal;

u ₀ is the detection threshold;

u is the amplitude of the signal received in the tracking strobe of the checked trajectory when the probe signal is emitted.

Other mathematical expressions are also possible for determining the power of a false probe depending on the functions performed by a particular radar. There are two ways to reduce the power of a sounding signal:

раз или более;1) reduce the transmitter power in $${\left(\frac{u_0}{u}\right)}^2$$

once or more;

2) reduce the gain of the antenna for transmission by the same number of times, for example, by deflecting the beam relative to the inspected direction.

The second method is based on the fact that the antenna gain depends on the angular direction of observation of the target. In the center of the antenna beam (in the main direction), the gain is maximum and as the angular position of the target deviates from the center of the beam, the antenna gain decreases. In proportion to this, the radiated power of the probing signal in the inspected direction also decreases. This fact is used to reduce the radiated power of the probe signal (false probe) in the inspected direction. If you reject the beam of the antenna radiation pattern (BOTTOM) for the duration of the radiation of the probe signal from the inspected direction, then the radiated power in this direction will decrease in accordance with the expression obtained similarly to (1):

where G _l.sonde is the antenna gain when the direction deviates from the main one, the magnitude of which is determined from the known dependence characterizing the DND [see, for example, Radar Reference. Ed. M. Skolnik, M., “Sov. radio ”, 1977, p. 54, 55, fig. 12];

G _probe - the gain of the antenna in the main direction (at the maximum of the beam).

Thus, the implementation of the proposed method allows you to recognize a false trajectory created by a synchronous response interference, which is achieved by the claimed result.

Claims (3)

1. A method for recognizing a false trajectory generated by a synchronous response interference, based on the installation of strobes to follow the recognized trajectory and detecting marks in them, characterized in that they emit a sounding signal of reduced power — a false probe, in which the reflected signal from a real target will be lower than the detection threshold and set the recognizable trajectory to the sign “false” if a mark is detected in the strobe. 2. The method according to p. 1, characterized in that the power of the false probe is determined from a mathematical expression

where R _{L. probe} - the power of the false probe;
P _probe is the power of the probing signal;
u ₀ is the detection threshold;
u is the measured amplitude of the signal received in the tracking strobe of the checked trajectory when the probe signal is emitted. 3. The method according to p. 1, characterized in that the power of the false probe is set by reducing the gain of the antenna in the viewed direction due to the deviation of the beam from the radiation direction for the duration of the radiation of the false probe.