A radar jamming device and method based on polarization dimension

Abstract

The application relates to the technical field of radar electronic countermeasure, and discloses a radar jamming device and method based on a polarization dimension. The device comprises a quadrature dual-polarized antenna unit, a microwave unit comprising a digital control attenuator, a signal generation unit comprising a digital module and a master control module, and a power amplifier unit. The application adopts an amplitude-phase independent decoupling modulation architecture: in the detection stage, the polarization state of the input signal is judged by measuring the instantaneous amplitude-phase characteristics of the H-path and V-path components after frequency conversion, and using a multi-point summation average and variance threshold limiting algorithm; in the synthesis stage, the digital module internally performs digital phase modulation, and synchronously outputs a control code to adjust the digital control attenuator of the microwave link to perform hardware amplitude modulation, so that an arbitrary polarized signal is finally synthesized in space. The application realizes accurate countermeasures against the polarization dimension of the radar, can effectively cope with sidelobe cancellation and other anti-jamming mechanisms, and has the advantages of high integration, strong flexibility, high recognition accuracy and the like.

Description

Technical Field

[0001] This invention belongs to the field of radar electronic countermeasures technology, specifically relating to a radar jamming device and method based on polarization dimension. Background Technology

[0002] With the continuous evolution of radar anti-jamming technology, traditional jamming equipment faces severe challenges. Existing radar jamming equipment generally only constructs complex electromagnetic environments in three dimensions: spatial domain, frequency domain, and energy domain to achieve jamming. However, radar anti-jamming methods targeting these three dimensions have become increasingly mature (such as spatial filtering, frequency diversity, and power control), leading to a gradual decline in the effectiveness of traditional jamming equipment, making it difficult to meet the needs of modern complex radar countermeasure scenarios.

[0003] To overcome the aforementioned technical bottlenecks, it is urgent to explore new dimensions of interference. The polarization characteristics of electromagnetic waves, as one of the key parameters of radar signals, have not yet been fully utilized in jamming equipment. Existing jamming equipment generally suffers from the following shortcomings: first, the polarization mode is fixed, making it impossible to flexibly adjust the polarization direction of the target signal and the jamming signal; second, it lacks closed-loop adaptive capability, making it difficult to counter the polarization anti-jamming mechanisms of modern advanced radar systems (especially precision tracking radars with sidelobe cancellation (SLC) and sidelobe concealment (SLB) functions by detecting polarization characteristics and dynamically switching polarization modes. Therefore, developing a new type of jamming equipment based on the polarization dimension has become a key technical direction for improving radar jamming effectiveness. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to address the shortcomings of existing jamming devices, such as fixed polarization modes and lack of polarization detection and dynamic response capabilities. This invention provides a radar jamming device and method based on polarization dimension, which can flexibly and arbitrarily synthesize and control the polarization direction of target signals and jamming signals.

[0005] Technical solution: The radar jamming device with polarization detection and arbitrary synthesis functions described in this invention includes:

[0006] The antenna unit includes a receiving antenna and a transmitting antenna, both of which are orthogonal dual-polarized antennas, used to receive and transmit mutually orthogonal horizontal polarization component signals and vertical polarization component signals, respectively.

[0007] A microwave unit is connected to the receiving antenna and the transmitting antenna respectively. The microwave unit includes a down-conversion link and an up-conversion link. The up-conversion link is equipped with two digitally controlled attenuators.

[0008] The signal generation unit includes a digital module and a main control module; the digital module is connected to the microwave unit and is used to perform analog-to-digital conversion and baseband processing on the signal output from the downconversion link, as well as to generate baseband target analog signals and interference signals to be sent to the upconversion link; the main control module is connected to the digital module and is used for command parsing and status monitoring.

[0009] The power amplifier unit is connected between the upconversion link of the microwave unit and the transmitting antenna, and is used to amplify the radio frequency signal and send it to the transmitting antenna for radiation.

[0010] The digital module and the microwave unit adopt an amplitude-phase independent decoupled modulation architecture: in the detection stage, the polarization state of the input signal is determined by measuring the instantaneous amplitude and instantaneous phase of the two down-converted components; in the synthesis stage, the digital module performs digital phase modulation on the two baseband signals internally, and adjusts the attenuation of the two digitally controlled attenuators in the microwave unit by outputting attenuation control codes to perform hardware amplitude modulation, and synthesizes a signal with arbitrary polarization direction in space by the power ratio and phase difference of the two signals.

[0011] This invention also provides a method for radar signal polarization detection and synthesis, comprising the following steps:

[0012] Step S1: Obtain the horizontal polarization component and vertical polarization component of the radar radio frequency signal to obtain the baseband I and Q signals of the two components;

[0013] Step S2: Measure the instantaneous amplitude of the horizontal polarization component based on the baseband I and Q signals. and instantaneous phase and the instantaneous amplitude of the vertical polarization component. and instantaneous phase And use variance thresholding to exclude high-noise measurement points;

[0014] Step S3: Calculate the amplitude ratio parameter and phase difference parameter Based on this, the polarization state of the current input signal can be determined;

[0015] Step S4: Generate polarization control parameters based on the discrimination result, and perform amplitude and phase independent decoupling modulation on the dual digital baseband signals, including: adjusting the phase difference between the two signals by digital phase shifting, and simultaneously adjusting the power ratio of the two RF signals by hardware digitally controlled attenuator;

[0016] Step S5: The two modulated radio frequency signals are spatially vector synthesized through an orthogonal dual-polarized antenna to form an interference signal or target simulation signal with preset polarization characteristics.

[0017] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows:

[0018] The invention employs a combined hardware and software architecture that integrates digital baseband phase modulation and microwave hardware amplitude modulation. By controlling the phase difference between the dual-channel orthogonal baseband signals and utilizing a digitally controlled attenuator to control the power ratio, it can vector synthesize linearly polarized, circularly polarized, or elliptically polarized signals at arbitrary angles in space. This structure overcomes the limitation of polarization in traditional single-antenna systems.

[0019] The equipment possesses precise polarization detection capabilities. By extracting a "polarization phase descriptor" composed of amplitude ratio and phase difference parameters, and in conjunction with built-in polarization decision tree logic, it can accurately identify radar pulses. Combined with a pulse-by-pulse polarization jamming strategy, the equipment can adaptively change its transmitted polarization in real time according to the polarization characteristics of the enemy radar, significantly disrupting the angle direction finding, sidelobe cancellation (SLC), and sidelobe concealment (SLB) functions of modern precision radar.

[0020] During the polarization parameter extraction process, a multi-point summation averaging and variance threshold limiting mechanism was introduced to effectively filter out invalid or high-noise measurement points. At the same time, the coupler and down-conversion link set at the end of the power amplifier unit form a closed-loop self-calibration channel, realizing real-time self-calibration of the amplitude and phase of the device's transmitted signal, which greatly improves the polarization synthesis accuracy and system reliability under extreme electromagnetic environments.

[0021] By setting up a polarization combination switching network consisting of a combiner, a power divider, and multiple RF switches at the end of the frequency conversion link in the microwave unit, orthogonal polarization hardware switching within a pulse, between pulses, or between pulse groups can be quickly completed in a pure hardware routing manner, taking into account both the high precision of digital modulation and the high-speed response characteristics of hardware switches. Attached Figure Description

[0022] Figure 1 The diagram shows the framework of the polarization interference device, illustrating the hierarchical relationship between the various subsystem modules.

[0023] Figure 2 This is a schematic diagram of a polarization interference device, illustrating the signal flow logic between various units.

[0024] Figure 3 A schematic diagram of the setup for polarization interference equipment.

[0025] Figure 4 This is a diagram illustrating a wired application scenario for controlling a polarization interference device via its network port.

[0026] Figure 5 This diagram illustrates a scenario for wireless data transmission control of polarization interference devices.

[0027] Figure 6This is a schematic diagram of the internal structure of the polarization interference equipment chassis (including the layout of the main functional modules).

[0028] Figure 7 This is the assembly drawing of the polarization interference equipment.

[0029] Figure 8 Detailed internal assembly diagram of the chassis. Figure 8 'a' is the main view. Figure 8 b in the figure represents the distance along the path. Figure 8 (a) Structural diagram along direction AA, Figure 8 In the diagram, 'c' represents the side view.

[0030] Figure 9 This is a detailed assembly diagram of an orthogonal polarized antenna. Figure 9 'a' is the main view. Figure 9 In this context, 'b' represents the top view. Figure 9 In the diagram, 'c' represents the side view.

[0031] Figure 10 This is a schematic diagram of the vector relationships of various elliptic polarization states in the XY plane.

[0032] Figure 11 This is a simulation diagram of horizontally polarized plane electromagnetic wave propagation.

[0033] Figure 12 This is a simulation diagram of vertically polarized plane electromagnetic wave propagation.

[0034] Figure 13 This is a simulation diagram of the propagation of a 45° obliquely polarized plane electromagnetic wave.

[0035] Figure 14 This is a simulation diagram of the propagation of a 135° obliquely polarized plane electromagnetic wave.

[0036] Figure 15 This is a simulation diagram of the propagation of a left-handed circularly polarized plane electromagnetic wave.

[0037] Figure 16 This is a simulation diagram of right-hand circularly polarized plane electromagnetic wave propagation.

[0038] Figure 17 This is a simulation diagram of a left-handed elliptical polarized plane electromagnetic wave and its projection onto the XY plane.

[0039] Figure 18 This is a simulation diagram of a right-handed elliptical polarized plane electromagnetic wave and its projection onto the XY plane.

[0040] Figure 19 This is a flowchart of the polarization discrimination algorithm.

[0041] Figure 20 This is a schematic diagram of the final-stage polarization combination switching network and the closed-loop coupled link.

[0042] Figure 21 This is a block diagram illustrating the principle of amplitude-phase decoupling control, showing the interaction between digital phase modulation and hardware amplitude modulation.

[0043] In the diagram: 1-Chassis unit; 2-Orthogonal polarized antenna unit; 3-External data transmission module; 4-Tripod; 5-RF connection cable; 6-Front panel; 7-Rear panel; 8-Top cover; 9-Base plate; 10-8-18GHz horn antenna; 11-Linkage support mechanism; 12-AC / DC power module; 13-Power amplifier unit 1; 14-Power amplifier unit 2; 15-Built-in wireless data transmission module; 16-Power conversion module; 17-Signal generation unit; 18-Microwave components. Detailed Implementation

[0044] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments described.

[0045] Example 1: Refer to Figures 1-6 This embodiment provides a radar jamming device with polarization detection and arbitrary synthesis functions. It adopts a modular distributed design and operates in the frequency band of 8–18 GHz. The entire system consists of an antenna unit, a microwave unit, a power amplifier unit, a signal generation unit (including a digital module and a main control module), a display and control unit, a power supply unit, and a wireless data transmission unit.

[0046] The antenna unit includes an orthogonal dual-polarized receiving antenna and an orthogonal dual-polarized transmitting antenna. The receiving antenna outputs two radio frequency signals, one with a horizontal polarization component (H-path) and the other with a vertical polarization component (V-path), which are orthogonal to each other. The transmitting antenna performs vector radiation superposition of the two radio frequency signals amplified by the host in space to synthesize an electromagnetic wave with preset polarization characteristics.

[0047] The microwave unit includes downconversion links and upconversion links (upconversion link 1 and upconversion link 2). The downconversion link is responsible for converting the received RF signal to an intermediate frequency (IF) of 1.3 GHz–2.3 GHz; the upconversion link is responsible for converting IF interference signals to an IF of 8–18 GHz. The upconversion link is equipped with two independent digitally controlled attenuators for performing high-precision hardware amplitude modulation. In addition, the microwave unit provides a 2.4 GHz reference clock signal for the digital module.

[0048] The power amplifier unit contains independent H-channel and V-channel power amplifier modules, used to amplify the small signals sent from the microwave unit. Its output is equipped with a coupler, which splits the sampling signals into two channels and connects them to the coupling input of the microwave unit, forming a closed-loop feedback link for amplitude and phase measurement.

[0049] The signal generation unit includes a digital module and a main control module. The digital module has a built-in multi-channel high-speed A / D and D / A converter and an FPGA chip, which performs core signal processing such as PDW measurement, polarization parameter extraction, and digital phase modulation. The main control module is responsible for parsing instructions, realizing message interaction with the host computer, and executing polarization interference strategy control logic.

[0050] The display and control unit includes a display and control computer and display and control software. It mainly provides a human-computer interaction platform, which makes it convenient for operators to control the polarization interference device to generate corresponding polarization signals according to their needs.

[0051] The power supply unit converts the externally input 220V AC power into 24V DC power to provide the voltage required for the operation of the whole machine.

[0052] The supporting auxiliary units mainly ensure the normal use and transportation of the equipment in the field, including supporting cables, packaging boxes, chassis structural components, wireless data transmission, and tripods. The wireless data transmission consists of two data transmission modules, one of which is built into the chassis with a data transmission antenna interface on the chassis panel, and the other is used on the ground. The ground-based data transmission module is connected to the display and control laptop via a network cable. After the host computer software issues commands, the parameter data is transmitted to the host computer through the data transmission antenna.

[0053] Example 2: This example combines Figure 2 The working principle, signal flow, and structural layout of polarization interference equipment are explained in detail.

[0054] 1. Principles of the detection and signal processing link

[0055] Reference Figure 2 The operating frequency range of this polarization interference device is 8-18GHz. It can achieve network port communication between the display and control computer and the device host through a network cable, and can also achieve remote communication through wireless data transmission.

[0056] The signal flow during the detection phase is as follows: External electromagnetic waves are captured by an 8–18 GHz orthogonally polarized horn antenna, whose H-channel and V-channel feed ports are connected to the RF input interface of the microwave unit. The microwave unit integrates an RF switch, which enables time-division multiplexing of the RF signals from the H and V feed ports. The time-division received signals are amplified with low noise within the microwave unit and then down-converted to an intermediate frequency (IF) of 1.3 GHz–2.3 GHz by a down-conversion link. These signals are then sent to a digital module for PDW (Pulse Description Word) measurement. The main control module sorts and processes the measurement data and uploads the results to the display and control unit via Ethernet or wireless data transmission. Finally, the polarization characteristic parameters of the target radar are displayed in real-time on the display and control software interface.

[0057] 2. Principles of Signal Generation, Modulation, and Transmission

[0058] Reference Figure 2 and Figure 21 The working logic of the transmission link is as follows:

[0059] The frequency combiner module generates a highly stable 2.4GHz clock signal, providing a unified clock reference for the digital modules. The digital modules generate one analog target signal (1.3GHz~2.3GHz) and one interference baseband signal according to preset instructions. These signals are sent to two independent upconversion links in the microwave unit via a high-speed DAC, where they are upconverted into 8~18GHz radio frequency signals and then amplified by the corresponding power amplifiers.

[0060] Variable polarization modulation mechanism: This device supports dynamic control of the polarization characteristics of the output signal.

[0061] Phase modulation: The digital module directly performs phase shifting on the baseband signal internally based on the polarization parameters sent by the host computer.

[0062] Amplitude Modulation: The digital module outputs control codes, which change the amplitude ratio of the output signal by adjusting the attenuation values ​​of the two digitally controlled attenuators in the microwave unit.

[0063] The modulated radio frequency signal is ultimately radiated into the external space by an 8-18 GHz orthogonal polarized antenna, achieving polarization interference.

[0064] 3. Closed-loop self-calibration principle

[0065] Reference Figure 2 and Figure 20 To compensate for amplitude and phase errors caused by ambient temperature, cable loss, and device nonlinearity, a closed-loop self-calibration link was designed for the system:

[0066] Each of the two 8-18 GHz power amplifiers has a coupler at its output to split into two small-signal sampling paths. These two sampled signals are fed back to the two coupled inputs of the microwave unit, processed by the down-conversion link, and then sent back to the digital module. The digital module performs real-time amplitude and phase measurements on the sampled signals, calculates the actual deviation of the current transmit link, and automatically corrects the modulation parameters to ensure the accuracy of polarization synthesis.

[0067] 4. Control Logic and Communication Guarantee

[0068] The main control module, as the core control hub of the host, has two-way interactive capabilities:

[0069] Downlink control: Parses the instructions and parameter messages sent by the host computer and transmits them to the digital module to control the local oscillator frequency and attenuator status of the microwave unit.

[0070] Uplink monitoring: Real-time acquisition of status information such as operating current, voltage and temperature of each submodule, and uploading to the display and control unit to achieve real-time monitoring of the entire system.

[0071] In terms of communication, the device supports wired communication between the display and control computer and the host via twisted-pair network cable. Figure 4 (Scene), and also has a built-in wireless data transmission module, supporting remote wireless communication in complex outdoor environments ( Figure 5 Scene).

[0072] 5. Usage Scenarios ( Figure 4 , Figure 5 )

[0073] The equipment was actually erected ( Figure 3 After that, the operator can use the human-machine interface of the display and control unit to communicate via the network port. Figure 4 or wireless data communication Figure 5 It issues polarization control parameters and monitors the polarization parameters of the sorted radar signals in real time, thereby providing precise support for multi-dimensional combat missions in complex electromagnetic environments.

[0074] 6. Power Supply and Structural Physical Implementation Details

[0075] This invention employs standardized, modular, and highly reliable heat dissipation design in its physical structure. Combined with... Figures 6 to 9 The specific structural implementation method is as follows:

[0076] like Figure 6 , 7 The illustrated system setup utilizes a tripod 4 for stable field installation, with the chassis unit 1 mounted on a top adapter platform of the tripod 4. Multiple 8-18GHz horn antennas 10 are mounted on either side or top of the chassis unit 1 via a linkage mechanism, forming an orthogonal polarized antenna unit 2. The RF output interface on the front panel 6 of the chassis unit 1 is connected to the feed ports of the horn antennas 10 via multiple RF cables 5 of varying lengths. Furthermore, the system is equipped with an external data transmission module 3 for establishing a remote command link with the wireless data transmission terminal inside the chassis.

[0077] Reference Figure 8 Internal Module Layout and Heat Dissipation: Chassis Unit 1 employs a compact, distributed layout to achieve lightweight design and efficient heat dissipation. The chassis is enclosed by a front panel 6, a rear panel 7, a top cover 8, and a bottom plate 9. Inside the chassis, distributed and flush against the aluminum alloy outer shell, are mounted an AC / DC power module 12, a power amplifier unit 13, a power amplifier unit 14, a built-in wireless data transmission module 15, and a power conversion module 16. Power amplifier units 13, 14, and the microwave unit 18 rapidly transfer the generated heat to the aluminum alloy chassis shell via heat-conducting components such as high thermal conductivity heat pipes or thermally conductive rubber pads, utilizing natural convection heat dissipation on the chassis surface. The front panel 6 also features auxiliary airflow components to enhance internal airflow in high-temperature environments.

[0078] The AC / DC power module 12 is installed inside the chassis on one side, converting the external 220V AC mains power into 24V DC power for the entire unit's operation. It further provides the necessary secondary voltage to the built-in wireless data transmission module 13 and digital circuits via the power conversion module 15. All hardware interfaces use standard aviation connectors and are located on the front panel 6, ensuring reliable connection and quick assembly / disassembly capabilities in complex environments.

[0079] See Figure 9 The antenna support mechanism shown is detailed in the diagram. The mechanical structure of the orthogonal polarized antenna unit 2 is precisely assembled from multiple sets of linkage support mechanisms 11. This mechanism, through the combination of linkages and supports, ensures that the 8-18GHz horn antenna 10 maintains a preset geometric phase relationship relative to the chassis unit 1, thereby ensuring that the two radio frequency signals can accurately synthesize the required polarization vector during spatial radiation. All linkage and support components adopt a standardized design, possessing good interchangeability, facilitating the addition or reduction of the number of antennas or adjustment of the polarization axis according to mission requirements.

[0080] Example 3: Given the current state of affairs where the system interference mechanism of polarization jamming on modern radar, especially its sidelobe cancellation (SLC) and sidelobe concealment (SLB), is not fully understood, the core application of the polarization jamming device described in this invention lies in its ability to systematically explore the angular misleading potential of such polarization modulation signals on the angle measurement system of precision tracking radar by accurately simulating advanced angle deception jamming modes and polarization diversity jamming techniques centered on cross-polarization jamming. Furthermore, it focuses on quantitatively evaluating the actual suppression and deception effects on the adaptive cancellation algorithm of sidelobe cancellation (SLC) and the logic of sidelobe concealment (SLB), thereby providing key experimental data for equipment development and performance evaluation.

[0081] To achieve precise strikes and effectiveness assessments against complex radar anti-jamming mechanisms, the primary prerequisite is to establish a high-precision underlying polarization detection and synthetic physical model. The implementation details of the polarization detection and discrimination algorithm of this invention are as follows:

[0082] During the detection phase, the equipment performs real-time polarization measurements on external electromagnetic waves. Assuming the existence of a monochromatic TEM plane wave propagating along the +z direction, its instantaneous electric field vector is characterized as:

[0083]

[0084] in, The frequency of electromagnetic waves, For propagation wavenumber, and For the amplitude and phase of the H-path component, and The amplitude and phase of the V-path component.

[0085] Writing electromagnetic waves in the form of complex vectors:

[0086]

[0087] The complex electric field vector is:

[0088]

[0089] The polarization information of an electromagnetic wave mainly depends on the amplitude ratio and phase difference of signals in two orthogonal directions on an equiphase surface. Ignoring absolute phase information, the complex electric field vector can be expressed as:

[0090]

[0091] in, It indicates Directional electric field amplitude and The ratio of the amplitude of the directional electric field express Directional electric field and Phase difference of directional electric field, parameters , The energy information and parameters of electromagnetic waves are omitted. A phase descriptor that corresponds one-to-one with the polarization state of an electromagnetic wave is called the phase descriptor of the electromagnetic wave polarization state.

[0092] This device uses an orthogonal dual-polarized antenna for receiving signals, capable of receiving signals of arbitrary polarization and decomposing them into H-channel and V-channel signals, respectively. Let H and V represent the horizontal and vertical received signals, respectively. The theoretical values ​​of the receiving antenna's H and V are given below, as follows: Figure 10 The following are schematic diagrams of various elliptic polarizations:

[0093] Horizontal polarization: ;

[0094] Vertical polarization: ;

[0095] Oblique polarization (45° as an example):

[0096]

[0097] Oblique polarization (135° as an example):

[0098]

[0099] Circular polarization (right-handed as an example):

[0100]

[0101] Circular polarization (left-handed as an example):

[0102]

[0103] Example 4: This example combines Figures 11 to 18 and Figure 19 The process logic is shown to demonstrate the simulation and discrimination process of the polarization interference device of the present invention for various typical polarization waves, which is used to verify the calculation accuracy of the digital module after obtaining the instantaneous amplitude and phase characteristics.

[0104] In the simulation experiment, it is assumed that the input signal is a monochromatic TEM plane wave, and the digital module measures the instantaneous amplitude of the H-path and V-path components ( ) and phase difference ( After processing, the following judgment results were obtained:

[0105] 1. Simulation of linear polarization detection and discrimination

[0106] like Figure 11 The horizontal polarization simulation diagram shown: The input parameters are set as follows: The digital module calculates the amplitude ratio parameter. Based on the decision logic, the system determines that the currently received signal is a horizontally polarized wave.

[0107] like Figure 12 The vertical polarization simulation diagram shown: The input parameters are set as follows: The digital module calculates the amplitude ratio parameter. The system determines that the currently received signal is a vertically polarized wave.

[0108] like Figure 13 The simulation diagram of 45° oblique polarization shown: The input parameters are set as follows: Phase difference At this point, the two paths have equal amplitude and are in phase, and the system calculates and determines that it is a 45° oblique polarization wave.

[0109] like Figure 14 The 135° slant polarization shown: The input parameters are set as follows: Phase difference At this point, the two amplitudes are equal and out of phase, and the system calculates and determines that it is a 135° oblique polarized wave.

[0110] 2. Simulation of Circular Polarization Detection and Discrimination

[0111] like Figure 15 The simulation diagram of left-handed circular polarization shown: The input parameters are set as follows: Phase difference The two components have equal amplitudes, and the V-path leads the H-path by 90°. Based on the sign of the phase difference, the system determines that it is a left-hand circularly polarized wave.

[0112] like Figure 16 The simulation diagram of right-hand circular polarization shown: The input parameters are set as follows: Phase difference The two components have equal amplitudes, and the H-path leads the V-path by 90°, so the system determines it to be a right-hand circularly polarized wave.

[0113] 3. Simulation of Elliptic Polarization Detection and Discrimination

[0114] In elliptical polarization scenarios, in addition to determining the rotation direction, the system further calculates the ratio of the major axis to the minor axis (axis ratio) and the angle of deviation of the major axis relative to the coordinate axes (tilt angle):

[0115] like Figure 17 The simulation diagram of left-handed elliptic polarization shown: The input parameters are set as follows: Phase difference Calculated using the built-in formula in the digital module, its polarization characteristics are: left-handed elliptic polarization, with an elliptic axis ratio of 2.4842 and a major axis deviation from the y-axis of -16.845°.

[0116] like Figure 18 The simulation diagram of right-handed elliptic polarization shown: The input parameters are set as follows: Phase difference The system calculation results show that its polarization characteristics are: right-handed elliptic polarization, elliptic axis ratio of 3.2255, and major axis deviation from the y-axis of -21.6569°.

[0117] As can be seen from the above eight sets of simulation comparisons, the polarization interference device described in this invention can automatically distinguish signals covering the entire polarization domain, including horizontal, vertical, tilted, circular, and elliptical signals, by accurately extracting the amplitude and phase descriptors of the H-path and V-path.

[0118] Example 5: Signal Extraction and Noise Reduction: The digital module acquires the two baseband I and Q signals after down-conversion. When measuring instantaneous amplitude and phase, the system uses multi-point sampling and averaging to reduce random measurement errors. Simultaneously, the variance of the multi-point data is calculated in real time and compared with a preset threshold limit. The variance threshold limit is used to filter out invalid or high-noise polarization measurement points.

[0119] Step 1: Polarization descriptor calculation: Based on the measurement results, calculate the polarization phase descriptor. :

[0120] Amplitude ratio parameter: This indicates the amplitude ratio between the two signals.

[0121] Phase difference parameter: , which represents the phase difference between the two signals.

[0122] Step 2: As Figure 19 The polarization discrimination flowchart is shown below:

[0123] Calculate the amplitude ratio and phase difference between the two channels:

[0124] Linear polarization ( Figure 11-14 ):like (Horizontal polarization) (Vertical polarization), or or If it is oblique polarization, then it is determined to be linear polarization.

[0125] Step 3: Circular polarization ( Figure 15-16 If the linear polarization condition is not satisfied, and when at the same time (Right now When ), it is determined to be circularly polarized. If This is left-handed circular polarization. This is right-handed circular polarization.

[0126] Step 4: Elliptic polarization ( Figure 10 , 17 18): If none of the above conditions are met, then it is determined to be an elliptic polarized wave. The system further calculates the elliptic axis ratio. and the tilt angle deviating from the original xy axis :

[0127]

[0128] Example 6: Implementation details of arbitrary polarization synthesis and amplitude-phase modulation

[0129] In the synthesis stage, this invention employs an amplitude-phase independent decoupled modulation architecture to achieve arbitrary synthesis of polarization vectors (see...). Figure 21 ):

[0130] Digital phase modulation: The digital module (FPGA) directly performs digital phase shifting on the signals when generating dual-path baseband interference signals based on polarization control parameters, precisely controlling the phase difference between the H-path and V-path. .

[0131] Hardware amplitude modulation: The digital module synchronously outputs attenuation codes to control the high-precision digitally controlled attenuator in the microwave unit's upconversion link, adjusting the amplitude ratio of the two output powers. .

[0132] Because this invention employs "cross-physical-domain" amplitude-phase decoupling modulation, a group delay difference inevitably exists between the digital phase modulation link and the microwave RF amplitude modulation link. Without compensation, this will lead to distortion of the synthesized polarization pulse envelope. Therefore, precise delay compensation logic is configured between the digital module and the microwave unit.

[0133] The basic programmable logic unit (CLB) of the digital module is composed of a lookup table, a data selector, a carry chain, and registers. The lookup table and multiplexer perform combinational logic functions. In delay compensation, the system first transmits a synchronization test signal and uses closed-loop measurement to obtain the absolute delay difference between the digital phase modulation (DPM) link and the microwave amplitude modulation (MAM) link. Subsequently, the system pre-calibrates this delay difference using registers and inserts corresponding delays into links with faster timing (such as the digital control path corresponding to the MAM link). Specifically: for delay differences that are integer multiples of the sampling period, the delay is directly achieved using registers within the digital module; for delay differences that are not integer multiples of the sampling period, precise delay adjustment is performed by introducing a fractional delay interpolation algorithm in the baseband. Through this mechanism, the digital phase modulation signal and the microwave amplitude modulation signal achieve nanosecond-level strict time alignment at the antenna radiating aperture.

[0134] Under broadband operating conditions, microwave digitally controlled attenuators inevitably introduce parasitic additional phase shifts (AM-PM effect) that vary with frequency and attenuation level when changing the attenuation adjustment ratio. To address this engineering defect, this invention introduces a pre-compensation technique based on a three-dimensional lookup table (3D LUT). A vector network analyzer was used to test the RF link, establishing and storing a standard three-dimensional codeword table corresponding to "frequency-phase-attenuation" in the main control module. During actual operation, the digital module automatically queries this table to obtain the parasitic additional phase value at the corresponding attenuation level based on the currently detected radar signal frequency. Subsequently, during baseband digital phase modulation, an inverse compensation phase is automatically superimposed, thereby completely avoiding phase misalignment and polarization signal quality degradation caused by changes in RF frequency or attenuation.

[0135] Considering the measurement and system tolerances in actual engineering, a phase error tolerance is preset in this embodiment. This is related to amplitude isolation / error threshold. The specific mapping relationship is as follows:

[0136] The amplitude difference is greater than the preset isolation threshold (corresponding to the polarization angle). tending to or When synthesizing horizontal or vertical single-polarization signals;

[0137] Phase difference is or (corresponding phase difference) for or When the amplitude difference is adjusted, oblique polarization signals at any angle can be synthesized.

[0138] Phase difference is And the amplitude difference is within the preset error range of 0dB (corresponding to the phase difference). for And polarization angle for When ), spatially synthesized left-handed or right-handed circularly polarized signals;

[0139] Any combination of phase difference and amplitude difference that does not meet the above criteria for linear and circular polarization (i.e., the phase difference is neither equal to nor equal to the amplitude difference) or (When the strict equal-amplitude orthogonality condition of circular polarization is not met), synthesize elliptic polarization signals corresponding to tilt angle and axial ratio.

[0140] In addition, to meet the requirements of high-speed countermeasures, a polarization combination switching network is set at the end of the microwave unit, such as... Figure 20 As shown, the network includes a combiner, a power divider, and multiple RF switches (A / B / C / D). By parsing the issued control commands and controlling the pins (0 on, 1 closed), as shown in Table 1, the control code "0111" corresponds to the interference level, and "0011" corresponds to the interference polarization. The system can achieve hardware-level rapid polarization switching between intra-pulse and inter-pulse interference signals and target signals, thereby effectively countering the radar's sidelobe cancellation (SLC) mechanism and sidelobe concealment (SLB).

[0141] Table 1. Different Combinations of Polarization

[0142]

[0143] The entire link is divided into two independent channels, H and V. The signal outputs of the two channels are respectively connected to the horizontal and vertical polarization ports of the dual-polarized antenna, forming the basis of orthogonal polarization processing. Phase modulation is performed in the digital module. According to the phase parameters sent by the host computer, the digital module modulates the phase of the baseband signal in the FPGA chip, generating two phase-modulated intermediate frequency (IF) signals. When the IF signals pass through the up-conversion link of the microwave unit, their amplitude is modulated by the digitally controlled attenuator in the link. The attenuation value of the digitally controlled attenuator is adjusted by the digital module. By adjusting the power and phase of the two channels, the horizontal and vertical components of the orthogonal polarization base have a certain power ratio and phase difference, realizing the full polarization domain polarization processing function. The principle of the intermediate polarization adjustment method in the software design is as follows: Figure 21As shown, the FPGA controls the phase difference between the two signals when generating the baseband signal. In addition, the digital module controls the amplitude of the two signals by controlling the digitally controlled attenuator in the microwave unit, and finally realizes arbitrary polarization. The relationship between polarization pattern and amplitude and phase is shown in Table 2.

[0144] Table 2. Arbitrary Polarization Synthesis Table

[0145]

[0146] Based on the aforementioned high-precision polarization synthesis and switching capabilities, the polarization jamming device of this invention constructs a closed-loop jamming and evaluation platform targeting modern radar sidelobe cancellation (SLC) and sidelobe concealment (SLB) as core adversarial targets. The specific execution steps are as follows:

[0147] The first step is to establish a system performance benchmark: In an interference-free airspace environment, this equipment simulates the interaction between target signals and the radar system, measures and records the normal SLC cancellation gain and SLB target recognition accuracy of the radar, and establishes the system's benchmark data.

[0148] The second step involves directional polarization suppression and deception: The jamming equipment is activated, focusing the jamming signal onto the radar sidelobe region via a sidelobe directional antenna. Tactically, precise polarization matching is used to achieve directional jamming of the radar sidelobe, deliberately avoiding triggering the radar main lobe's anti-jamming logic. During this process, the main control module utilizes a polarization combination switching network to dynamically modulate the polarization switching sequence (the equipment supports a minimum polarization transition time of 1µs). Through microsecond-level dynamic polarization orchestration within, between, and in pulse groups, orthogonal polarization jamming waves matching the auxiliary antenna polarization are continuously injected into the radar, disrupting the radar's adaptive countermeasures weights.

[0149] The third step is to quantify and evaluate the jamming effect: extract the radar system's response data after the jamming is released. For the suppression effect, calculate the main channel gain reduction rate caused by SLC cancellation, and the increase in radar sidelobe level; for the deception effect, calculate the target misjudgment rate and false target positioning deviation caused by the disruption of SLB logic.

[0150] The fourth step is effectiveness assessment: The degradation rate and deviation obtained in the third step are compared with the preset operational effectiveness threshold and the performance benchmark obtained in the first step to determine whether the current polarization jamming tactic has achieved the expected operational effectiveness. If not, the polarization parameters and timing of the digital module are adjusted accordingly. Example 7: Closed-loop self-calibration and intelligent strategy control

[0151] Closed-loop self-calibration: The coupled sampling signal fed back from the power amplifier unit is down-converted and then transmitted back to the digital module. The digital module extracts the actual amplitude and phase difference of the transmitted signal in real time and compares it with the theoretical target value. By automatically correcting the digital phase shift value of the FPGA and the control parameters of the microwave unit's digitally controlled attenuator, link temperature drift and device inconsistencies are compensated to ensure polarization synthesis accuracy.

[0152] The interference strategy modes are as follows:

[0153] Pulse-by-pulse polarization jamming mode: For each radar pulse received, the device executes IQ measurement and identification logic in real time and immediately synthesizes a jamming signal that corresponds to (is the same as or orthogonal to) the current radar polarization state, thereby achieving adaptive dynamic countermeasures.

[0154] Independent jamming mode: Polarization measurement is performed to obtain radar characteristic parameters within a preset window period, and continuous jamming is performed according to preset fixed or periodic polarization parameters outside the window period (jamming period).

[0155] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A radar jamming device based on polarization dimension, characterized in that, include: The antenna unit includes a receiving antenna and a transmitting antenna, both of which are orthogonal dual-polarized antennas, used to receive and transmit mutually orthogonal horizontal polarization component signals and vertical polarization component signals, respectively. A microwave unit is connected to the receiving antenna and the transmitting antenna respectively. The microwave unit includes a down-conversion link and an up-conversion link. The up-conversion link is equipped with two digitally controlled attenuators. The signal generation unit includes a digital module and a main control module; The digital module is connected to the microwave unit and is used to perform analog-to-digital conversion and baseband processing on the signal output from the downconversion link, as well as to generate baseband target analog signals and interference signals to be sent to the upconversion link; the main control module is connected to the digital module and is used to perform command parsing and status monitoring. The power amplifier unit is connected between the upconversion link of the microwave unit and the transmitting antenna, and is used to amplify the radio frequency signal and send it to the transmitting antenna for radiation. The digital module and the microwave unit adopt an amplitude-phase independent decoupled modulation architecture: in the detection stage, the polarization state of the input signal is determined by measuring the instantaneous amplitude and instantaneous phase of the two down-converted components; in the synthesis stage, the digital module performs digital phase modulation on the two baseband signals internally, and adjusts the attenuation of the two digitally controlled attenuators in the microwave unit by outputting attenuation control codes to perform hardware amplitude modulation, and synthesizes a signal with arbitrary polarization direction in space by the power ratio and phase difference of the two signals.

2. The radar jamming device based on polarization dimension according to claim 1, characterized in that, The microwave unit's downconversion link front end is equipped with a receiver switching switch for time-division multiplexing of the horizontal polarization component signal and the vertical polarization component signal. The microwave unit's upconversion link is equipped with a polarization combination switching network consisting of a first power divider, a second power divider, four RF switches, and two combiners corresponding to horizontal and vertical polarization. The two RF links output by the microwave unit are respectively connected to the first power divider and the second power divider. The two outputs of the first power divider are respectively connected to the horizontal polarization combiner and the vertical polarization combiner via the first RF switch and the second RF switch. The two outputs of the second power divider are respectively connected to the horizontal polarization combiner and the vertical polarization combiner via the third RF switch and the fourth RF switch. The digital module controls different on / off combinations of the four RF switches to achieve rapid hardware switching of interference signals between horizontal polarization, vertical polarization, and orthogonal polarization switching modes.

3. The radar jamming device based on polarization dimension according to claim 2, characterized in that... The main control module pre-stores a frequency-phase-attenuation three-dimensional codeword lookup table based on the vector network analyzer calibration. This lookup table records the parasitic additional phase generated by the digitally controlled attenuator at different radio frequency points under different attenuation levels. The digital module includes pre-compensation correction logic when performing digital phase modulation: it detects the frequency of the currently detected radar signal, queries the three-dimensional codeword lookup table according to the target hardware attenuation, obtains the corresponding parasitic additional phase value, and superimposes the reverse compensation phase when the baseband generates the phase modulation signal to eliminate the synthetic polarization phase distortion caused by changes in radio frequency or attenuation.

4. The radar jamming device based on polarization dimension according to claim 1, characterized in that, The digital module and the microwave unit are configured with time delay compensation logic to eliminate the group delay difference caused by cross-domain decoupling modulation: by transmitting a synchronous test signal, the time delay difference between the digital baseband phase modulation link and the microwave amplitude modulation link is measured; the digital module uses internal registers to insert compensation delay for the link with faster timing to achieve time alignment of the two signals at the antenna radiation aperture; compensation for integer multiples of the sampling period is achieved by digital register timing, and compensation for non-integer multiples of the sampling period is achieved by fractional delay interpolation algorithm.

5. The radar jamming device based on polarization dimension according to claim 1, characterized in that, The output terminal of the amplification link of the power amplifier unit is equipped with a coupler, which is used to feed the transmitted signal back to the downconversion link of the microwave unit and send it to the digital module. The digital module corrects the phase modulation parameters and attenuation control code based on the feedback amplitude and phase measurement values ​​to achieve closed-loop self-calibration of the polarization characteristics of the transmitted signal.

6. The radar jamming device based on polarization dimension according to claim 1, characterized in that, The main control module is equipped with polarization interference strategy control logic, which supports the following modes: Pulse-by-pulse polarization jamming mode: Real-time generation of polarization control commands that correspond to or are opposite to the polarization state of the currently received single radar pulse, driving the digital module to synchronously synthesize jamming signals; Independent interference mode: Polarization detection is performed during the preset measurement window, and interference synthesis is performed cyclically according to the preset fixed polarization parameters during non-measurement windows; Angle deception and sidelobe interference mode: Generate cross-polarization modulation signal, drive the signal generation unit to emit specific polarization diversity interference signal, and use the orthogonality between the synthesized polarization vector and the polarization of the target radar antenna to suppress and deceive the sidelobe cancellation adaptive algorithm or sidelobe concealment logic of the radar system; the polarization control command supports microsecond-level dynamic polarization switching at the intra-pulse, inter-pulse or pulse group level.

7. The method for radar signal polarization detection and synthesis using a radar jamming device based on polarization dimension according to claim 1, characterized in that, Includes the following steps: Step S1: Obtain the horizontal polarization component and vertical polarization component of the radar radio frequency signal to obtain the baseband I and Q signals of the two components; Step S2: Measure the instantaneous amplitude of the horizontal polarization component based on the baseband I and Q signals. and instantaneous phase and the instantaneous amplitude of the vertical polarization component. and instantaneous phase And use variance thresholding to exclude high-noise measurement points; Step S3: Calculate the amplitude ratio parameter and phase difference parameter Based on this, the polarization state of the current input signal can be determined; Step S4: Generate polarization control parameters based on the discrimination result, and perform amplitude and phase independent decoupling modulation on the dual digital baseband signals, including: adjusting the phase difference between the two signals by digital phase shifting, and simultaneously adjusting the power ratio of the two RF signals by hardware digitally controlled attenuator; Step S5: The two modulated radio frequency signals are spatially vector synthesized through an orthogonal dual-polarized antenna to form an interference signal or target simulation signal with preset polarization characteristics.

8. The method according to claim 7, characterized in that, In step S3, the polarization state is determined by the following logic: like for or ,or for or It was determined to be a linearly polarized wave; If the linear polarization criterion is not met, and when for at the same time for When, it is determined to be a circularly polarized wave, in which It is left-handed. It is right-handed; If none of the above conditions are met, it is determined to be an elliptic polarized wave, and its axial ratio and tilt angle are calculated.

9. The method according to claim 7, characterized in that, In step S4, the following mapping relationship is used to generate polarization control parameters: when the amplitude difference is greater than the preset isolation threshold, a horizontal or vertical single-polarization signal is synthesized; the phase difference is... or At that time, oblique polarized signals at arbitrary angles are synthesized using different amplitude differences; the phase difference is... When the amplitude difference is within a preset error range of 0dB, a left-handed or right-handed circularly polarized signal is synthesized; any combination of phase difference and amplitude difference other than those conditions above synthesizes an ellipticly polarized signal with corresponding characteristics; wherein, This is the preset phase error tolerance.

10. The method according to claim 7, characterized in that, In response to radar sidelobe cancellation (SLC) and sidelobe stealth (SLB) mechanisms, the following closed-loop suppression and evaluation tactical steps are also included: Establishing a benchmark: In an interference-free environment, establish a performance benchmark by measuring the SLC cancellation gain and SLB target recognition accuracy of the target radar; Directional suppression and deception: By using a sidelobe directional antenna, the interference signal is focused on the radar sidelobe region, and the polarization switching timing is dynamically modulated to make the interference polarization vector accurately match the polarization characteristics of the radar sidelobe, so as to avoid triggering the radar main lobe anti-interference logic. Effectiveness quantification: Extract radar response data after jamming release, calculate SLC cancellation gain reduction rate, radar sidelobe level rise, SLB misjudgment rate, and false target positioning deviation; and compare the calculation results with performance benchmarks to determine whether polarization jamming has reached the expected operational effectiveness threshold.

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