Method for protecting radar station with additional radiation source from high-precision weapons with passive homing head

Abstract

FIELD: radar technology.SUBSTANCE: invention relates to passive methods of protecting radar stations (RLS) from homing high-precision weapons (HPW) with a passive homing head (PHH), which include anti-radar missiles (ARM). The radar station and an additional radiation source (ARS) synchronized with it emit coherent signals in the direction of the spatial position of the ARM. These devices represent a source of spatially diverse interference to the passive homing head of a missile. The normal to the phase front of the resulting electromagnetic wave differs from the normal to the phase front of the radar. As a result, the missile's passive homing head is oriented in the direction of the false target, which is different from the direction of the protected radar. The condition for the interference impact is the provision at the input of the receiving antenna of the PGSN of an inversion zone of the total wave front of the resulting signal of the radiation sources with certain amplitude-phase relationships, as well as the provision of a change in the angular velocity of rotation of the missile-target line of sight.EFFECT: increased radar's protection against anti-missile missile attacks by diverting its guidance trajectory to a false point from the protected radar.1 cl, 2 dwg

Description

[0001] The invention relates to passive methods for protecting radar stations (RS) from homing high-precision weapons (HPW) with a passive homing head (PGSN), which include anti-radar missiles (ARM). The technical result of the invention is to increase the radar station's protection against anti-radar missile strikes by diverting its guidance trajectory to a false point away from the protected radar. This result is achieved by the radar station and an additional radiation source (ARS) synchronized with it emitting coherent signals in the direction of the ARM's spatial position. These means constitute a source of spatially diverse interference for the missile's passive homing head. The normal to the phase front of the resulting electromagnetic wave differs from the normal of the radar's phase front.As a result, the missile's passive homing head is oriented toward the false target, which is different from the direction of the protected radar. The jamming effect is achieved by ensuring that the homing head's receiving antenna has an inversion zone of the resulting wavefront of the radiation sources with specific amplitude-phase relationships, as well as by ensuring a change in the angular velocity of the missile-target line of sight.

[0002] A previously known passive defense method is to shift the anti-radar missile's guidance point away from the radar being protected. This shift can be achieved by using additional radiation sources and various types of reflectors. The following methods are known:

[0003] 1. A method based on the use of N spatially distributed additional radiation sources that generate distracting signals, the time and frequency parameters of which are controlled by a radar station. The signal emission period is shorter than the time constant of the AA missile control loop [1]. A disadvantage of this method is its insufficient guarantee of AA missile retargeting to the DI, due to the fact that the missile homing head distinguishes signals by their arrival time and angular coordinates.

[0004] 2. A method based on the use of N additional radiation sources for the protection of a radar station, located from each other at a distance not less than the destruction radius of the anti-radar missile warhead, within the range of 3 to 5 km. Control of the time and frequency parameters of the radiation sources is provided by the radar. The radiation sources form a jointly focused quasi-coherent radiation of distracting signals in the area of ​​the anti-radar missile goniometer, controlled by a deterministic change in the signal levels of N illumination stations. The radiation period of the distracting signals of the radiation sources is less than the constant of the anti-radar missile control loop [2]. The known method does not provide effective protection of radar stations from anti-radar missiles, since the goniometer homing device allows determining the direction of arrival of the electromagnetic wave from a certain radiation center, which usually coincides with the location of the radar antenna.

[0005] 3. Methods based on the use of an additional radiation source consisting of a transceiver and one [3, 4] (two [5]) passive radiation sources that provide retransmission of probing signals from the protected radar station. This method does not provide guaranteed protection for the radar due to the possibility of the anti-missile missile homing on the transmitter and hitting it with a probability close to one.

[0006] 4. A method based on the use of a re-radiating screen. Upon detection of an anti-radar missile and measurement of its angular coordinates and range, a radiation re-reflection device (RRD) is installed in advance at a certain base distance from the protected radar station. The azimuth of the RRD location, capable of changing the angular position of the re-radiating screen in accordance with control signals from the radar, is determined in advance. The screen is installed in such a way that the radar - RRD line is perpendicular to the expected direction of flight of the detected anti-radar missile. The required rotation angles of the re-radiating screen are calculated in the on-board radar computer [6]. The disadvantage of this method is the difficulty of achieving synchronous delivery of the radar probing signal and the signals re-reflected from the RRD to the receiving antenna of the anti-radar missile, as well as the one-time use of the RRD in the event of an anti-radar missile being aimed at it and due to its fire destruction.

[0007] 5. A method based on the use of two active additional radiation sources. The probing signals of the active radiation sources, which match in carrier frequency, duration, and repetition period, are emitted with an advance relative to the probing signal of the radar. [7]. A disadvantage of this method is the retargeting of the anti-radar missile to one of the active radiation sources or the radar at the final stage of guidance after the angular resolution of the radiation sources in space.

[0008] The common drawback of these methods is that using additional radiation sources to protect a radar does not guarantee retargeting of the anti-aircraft missile (AAM) to the decoy transmitter, due to the missile's homing head selecting received signals based on their arrival time and angular coordinates. When the AAM signals have sufficient energy to protect the radar, the AAM retargets the decoy transmitter and destroys it with a probability close to one. As a result, when several AAMs simultaneously attack a radar (a standard combat technique), after the first missiles destroy the decoy transmitters, subsequent missiles destroy the protected radar.

[0009] A method of protection against anti-radar missiles, which is closest to the claimed one and has been selected as a prototype, is known, based on the use of an additional elevating-type radiation source [8]. The specified technical result is achieved and consists in the fact that the additional radiation source is positioned in advance at a certain distance from the radar station and is deployed in the direction of the possible appearance of the anti-radar missile. After the anti-radar missile is detected and taken into tracking, distracting signals from the radar and the emitted radiation source are emitted. Throughout the entire phase of missile tracking, in order to ensure that the selector of the anti-radar missile homing head simultaneously passes the probing signals from the radar and the emitted radiation source, their delay time relative to each other is calculated. To shift the guidance point of the anti-radar missile from the protected radar station, the radar and emitted radiation sources signals are emitted with an amplitude ratio equal to 1, and the phase difference Δϕ=π is also maintained.This creates a significant distortion in the phase front position of the total electromagnetic wave received by the radar antenna. This, in turn, causes large errors in the radar's angular direction measurement device.

[0010] The specified method, selected as a prototype, does not provide effective protection of a radar station from an anti-radar missile, since it does not take into account the ability of the passive homing head of the anti-radar missile to spatially select, due to special angular gating schemes [9]. With the values ​​of the parameters of the radiation sources’ signals (amplitude ratio and phase difference) specified in the considered method, the direction of arrival of the total electromagnetic wave exceeds the value of the “angular gating (1.5-3°)”, and therefore is not processed.

[0011] Despite all the positive aspects of the invention, the method under consideration has a number of disadvantages:

[0012] 1. The passive homing head's ability to spatially select received signals, using special angular gating circuits, is not taken into account. Radar angular direction errors generated in the PGSN angle-measuring device exceed the "angular gating (1.5-3°)" value and, as a result, are discarded from processing [9].

[0013] 2. When generating interference, the proportional guidance method implemented in the missile system is not taken into account; in this case, in order to deviate the guidance trajectory, the effect of interference on the missile homing system must ensure a change in the rotation speed of the missile-target line of sight

[10] .

[0014] 3. The additional radiation source is equipped with a horn antenna, which does not ensure the formation of electromagnetic energy at a point in space with the required energy.

[0015] The aim of the invention is to create a method for protecting a radar station from anti-radar missiles by means of coordinated and controlled coherent radiation of probing signals from an additional radiation source and the radar station. The interference of the radiation source signals forms a distortion of the phase front of the total electromagnetic wave received by the homing antenna, causing errors in determining the true position of the radar. This leads to a deviation of the AA missile guidance trajectory to a remote point and a subsequent miss. This effect is explained in Fig. 1 and is based on known studies of the impact of two-point spatially diverse interference on single-pulse angle-measuring devices. The error in determining the direction on the radar when the angle-measuring device is exposed to spatially diverse interference formed by coherent probing signals from the protected radar and the DII is described by the formula of R.V. Ostrovityanova

[11] :

[0016]

[0017] where ϑ is the error in determining the direction to the radiation source;

[0018] d - the value of the base of spatially diverse interference sources;

[0019] δ - the ratio of the amplitudes of the signals of the study sources;

[0020] r0 - distance from the center of the base to the PRR;

[0021] ψ - angular direction to the PRR;

[0022] Δϕ - phase difference of radiation source signals;

[0023] λ - wavelength of radiation source signals.

[0024] The essence of the claimed invention (Fig. 2) is that a method is proposed for protecting a radar station with an additional radiation source from high-precision weapons with a passive homing head. The method consists of the protected radar station detecting an aerial object and, based on the recognition results, identifying it as a high-precision weapon with a passive homing head (an anti-radar missile). While tracking the anti-radar missile, its spatial coordinates and movement parameters are measured. The radar station, together with an additional radiation source located at a distance no less than the destruction radius of the anti-radar missile, emits synchronized coherent signals in the direction of the missile's spatial position.The claimed method differs from the existing method chosen as the closest analogue in that the additional radiation source is implemented as a transmitting station with a controllable antenna array and the ability to generate focused radiation. The direction of the additional radiation source's probing signals is determined by the radar station in accordance with the measured spatial position of the IR missile. The phase shift of the additional radiation source's signal and its time offset relative to the radar station's signal are determined by calculation using known formulas. Moreover, the radiation period in the direction of the missile is set to be shorter than the IR missile control loop time constant.

[0025] Fig. 2 shows a structural diagram of a protection device implementing the described method, which represents a sequential process of interaction of individual elements.

[0026] The device works as follows:

[0027] During spatial scanning, probing signals emitted by the radar station are fed through the receiving antenna of the additional radiation source to the input of the measurement and storage unit. The unit measures the parameters of the received signals (frequency, pulse duration, pulse repetition period, etc.), recognizes their types, and stores copies of the input signals in memory.

[0028] After detecting an anti-radar missile, the radar station begins tracking it. Information about the missile's spatial and extrapolated coordinates is sent from the radar station's measuring device to the control unit of the additional radiation source:

[0029]

[0030] where: - spatial coordinates of the radar at time t=n measured by the radar station; - extrapolated spatial coordinates of the PRR.

[0031] To ensure a change in the angular velocity of the missile-target line of sight under the influence of spatially diverse interference on the homing system of an anti-missile missile, it is necessary to estimate the change in the missile's course angle relative to the radar. For this purpose, the control unit of the experimental data analysis (DDI) determines the course angle of the anti-missile missile's movement based on measured spatial and extrapolated coordinates, as well as the known spatial coordinates of the radar's position:

[0032]

[0033] where: X R , Y R , Z R - known spatial coordinates of the radar.

[0034] The ability of the PGSN to select received radio pulses by arrival time with a leading edge cutoff of 0.25-0.8 μs necessitates precise alignment of the radiation source signals. For this purpose, the time offset of the DII signal relative to the radar signal is determined. Based on Fig. 1, the difference in the propagation distances of the radiation source signals is:

[0035]

[0036] Knowing the spatial position of the radiation sources, as well as the extrapolated coordinates of the rocket, the value is calculated based on the cosine theorem :

[0037]

[0038] where: - the angle between the direction of the radar - PRR and the radar - DII. Determining the value of the angle possible on the basis of the scalar product of the radar-PRR and radar-DII vectors connecting the points of their spatial position:

[0039] where: X D , Y D ,Z D - spatial coordinates of the DII.

[0040] Based on the value the required value of the shift in the time of emission of the signal of the additional radiation source relative to the radar signal is determined:

[0041]

[0042] where: c is the speed of light.

[0043] To ensure the impact of spatially diverse interference on the angle measuring device of the PGSN, taking into account the spatial selection of the PGSN, the following condition must be met:

[0044]

[0045] where: θ cmp - the value of the angular strobe of the angular gating circuit of the PGSN.

[0046] To fulfill condition (9), the phase difference value of the radiation sources is determined in the control unit of the additional radiation source to form the required error in determining the direction to the radar; for this, expression (1) is transformed to the form:

[0047]

[0048] where: values And are defined by the expressions:

[0049]

[0050] Stroke difference The phase shift of the probing signals from the radiation sources causes a change in the phase difference between the MRS and DII signals, determined by expression (10). Therefore, when determining the required phase shift of the additional radiation source received by the PGSN antenna, it is necessary to take into account the difference in wave paths:

[0051]

[0052] Control information (DII signal offset time Δτ n+1 phase shift of the DII F signal n+1 type of probing signal S n , as well as the code of the beam number of the directional pattern of the transmitting antenna DII K n+1 ) from the control unit of the additional radiation source is sent to the control unit.

[0053] The control unit uses signal offset time information to generate transmitter start and end pulses (INR, ICR), which are fed to the modulator. The signal phase shift value is fed to the phase shifter, which maintains the required phase shift. The beam number code of the transmitting antenna pattern is converted into β values ​​using a known array of beam numbers. n+1 ε n+1 , which is fed to the transmitting antenna.

[0054] Control signal that determines the type of probing signal S n The signal from the control unit is sent to the measurement and storage unit, which reproduces a copy of the previously recorded received radar signal. The generated copy of the signal from the measurement and storage unit is sent to the modulator, where the control pulses INR and ICR perform a time shift on the signal.

[0055] From the modulator output, the signal goes to the phase shifter where under the control signal F n+1The initial phase changes, and then it travels to the transmitting device, where it is amplified in power. Afterwards, it is radiated to the transmitting antenna in a given direction.

[0056] Thus, a method has been developed for protecting a radar station with an additional radiation source from high-precision weapons with a passive homing head. This method, based on the synchronized emission of coherent probing signals from the radar station and the additional radiation source, allows for the generation of spatially diverse interference for the angle-measuring device of the passive homing head of a high-precision weapon. This allows for the deflection of the attacking missile's trajectory to a false point that does not coincide with the actual location of the protected radar.

[0057] The distinctive features of the developed method are:

[0058] - when generating spatially diverse interference, the ability of a passive homing head to spatially and temporally select received emissions is taken into account, due to special angular gating circuits and cutting off the leading edge of the received radio pulse;

[0059] - dynamic change in angular tracking error allows for a change in the angular velocity of rotation of the missile-target line of sight and, as a consequence, a deviation in the guidance trajectory of high-precision weapons with a passive homing head, in which the proportional guidance method is implemented;

[0060] - the design of an additional radiation source with an antenna array allows focusing the radiation at the location of the angle measuring device of the passive homing head.

[0061] List of sources used

[0062] 1. Russian Federation Patent No. 2099734 dated 20.12.1997. Ivashechkin A.A., Leonov G.A. Method for protecting a group of radar stations from anti-radar missiles using additional radiation sources and device for its implementation. Application No. 96103564 / 09. Published 20.12.97.

[0063] 2. Russian Federation Patent No. 2205418 dated March 27, 2002. Gusevsky V.I., Nikiforov E.A., Pobedonostsev K.A., Sazonov D.M. Method of Protecting Radar Stations from Anti-Radar Missiles and Reconnaissance Aircraft. Application No. 2002107700 / 09. Published May 27, 2003.

[0064] 3. Russian Federation Patent No. 2152051 dated October 6, 1999. Alekseev V.G., Grigoriev A.B., Lebedev N.V., Marchenko I.N., Sentsov A.K., Pashchenko K.K., Fursov Yu.S. Method for protecting a radar station from an anti-radar missile and a system for its implementation. Application No. 99120774 / 09 dated October 6, 1999. Published June 27, 2000.

[0065] 4. Russian Federation Patent No. 2794223 dated May 23, 2022. Gorbachev A.P., Drobotun E.B., Sozykin A.G. Method for protecting radar stations from homing weapons and a device implementing it. Application No. 2022113851 dated May 23, 2022. Published April 13, 2023.

[0066] 5. Russian Federation Patent No. 2436114 dated March 31, 2010. Miloserdoe I.V., Fufaev S.A. Method of protecting a radar station from anti-radar missiles. Application No. 2010112601 / 09 dated March 31, 2010. Published December 10, 2011.

[0067] 6. Russian Federation Patent No. 2210089 dated 12.02.2001. Uspensky S.A., Mitrofanov D.G., Ponomarev A.N. Method of Protecting a Radar Station from an Anti-Radar Missile Based on the Use of a Re-Emitting Screen. Application No. 2001103933 / 09 dated 12.02.2001. Published 10.08.2003.

[0068] 7. Russian Federation Patent No. 2507533 dated 06.02.2012. Suslin M.A., Svischo V.S., Buslaev A.B., Rogovenko A.N. Method of Protecting a Radar Station from Anti-Radar Missiles Based on Additional Active Radiation Sources. Application No. 2012104048 / 07 dated 06.02.2012. Published 20.08.2013.

[0069] 8. Russian Federation Patent No. 2287168 dated 06.04.2005. Uspensky S.A., Mitrofanov D.G., Barsukov S.N., Kolosovsky A.V., Afonin S.V., Chuklyaev I.I., Pochechuev E.V., Redin A.V., Sergienko S.V., Ksenzov D.L. Method of protecting a radar station from an anti-radar missile based on the use of an additional lifting-type radiation source. Application No. 2005110005 / 09 dated 06.04.2005. Published on 10.11.2006 (prototype).

[0070] 9. Kosachev I.M. Tactical and technical characteristics, principles of combat use, mathematical models and the fight against anti-radar missiles: Monograph / Kosachev I.M. - Minsk: 2015. - 198 p: ill.

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