A Two-Dimensional Interference Resistant Method Based on Frequency Control Array

Abstract

This invention provides a two-dimensional anti-spatial filtering jamming method based on a frequency-controlled array, relating to the field of radar jammer design technology based on frequency-controlled arrays. The method involves applying a frequency offset to each array element to obtain initial frequency offset data; processing the transmitting radar signal to obtain baseband jamming signal data; deploying range-dimensional decoys based on the mapping relationship between decoy positions and frequency offsets using the initial frequency offset data and the jamming signal baseband data to obtain range-dimensional decoy signal data; correcting the frequency offset corresponding to the range-dimensional decoy signal data based on the mapping relationship between frequency offset and decoy velocity to obtain range-velocity two-dimensional decoy signal data; and using the radial distance between the radar and the jammer, performing phase modulation on the range-velocity two-dimensional decoy signal data to generate an anti-spatial filtering two-dimensional jamming signal. This invention solves the shortcomings of existing radar jamming technologies in multi-domain, multi-dimensional joint deception jamming.

Description

Technical Field

[0001] This invention relates to the field of radar jammer design technology based on frequency control arrays, and particularly to a two-dimensional jamming method for resisting airspace filtering based on frequency control arrays. Background Technology

[0002] Thanks to the development of digital radio frequency storage technology, jammers can intercept, store, modulate, and transmit the transmitted signals of target radars back to the target radar within a single pulse time, thus interfering with the radar. Depending on the modulation method, the jamming signal can cause different forms and degrees of interference to the radar. Benefiting from the inherent deception and jamming advantages of frequency-controlled arrays, research on jammer technology based on frequency-controlled arrays has become a hot topic in jammer design and jamming method research in recent years. By controlling the frequency offset of the jammer, range-dimensional or velocity-dimensional deception jamming can be performed on enemy radars. However, current radar signal processing technology can identify jamming targets from multiple domains and dimensions, greatly increasing the difficulty of deceiving and jamming radars. Furthermore, adaptive spatial filtering algorithms can adaptively suppress jamming signals from other directions while maintaining the signal power in the target direction, making conventional jamming algorithms ineffective. Therefore, there is an urgent need to research jamming algorithms that can simultaneously jam radars from multiple domains and dimensions and counter radar adaptive spatial filtering. Summary of the Invention

[0003] To address the aforementioned shortcomings in existing technologies, this invention provides a frequency-controlled array-based anti-spatial filtering two-dimensional interference method that solves the problem of insufficient multi-domain and multi-dimensional joint deception interference in existing radar jamming technologies.

[0004] To achieve the aforementioned objectives, the present invention employs the following technical solution: a two-dimensional anti-spatial filtering interference method based on a frequency-controlled array, comprising: S1: Using preset frequency control array parameters, apply frequency offset to each element of the frequency control array to obtain initial frequency offset data; S2: The intercepted radar signal from the transmitting source is down-converted and subjected to jamming modulation to obtain the baseband data of the jamming signal; S3: Based on the preset mapping relationship between the position and frequency offset of the false target, the range-dimensional false target is deployed using the initial frequency offset data and the baseband data of the interference signal to obtain the range-dimensional false target signal data; S4: Based on the preset mapping relationship between frequency offset and false target velocity, the frequency offset corresponding to the range-dimensional false target signal data is corrected to obtain range-velocity two-dimensional false target signal data; S5: Utilizing the radial distance between the radar and the jammer, phase modulation is performed on the range and velocity two-dimensional false target signal data to generate an anti-airspace filtered two-dimensional jamming signal, thus completing the anti-airspace filtered two-dimensional jamming.

[0005] Further, S2 includes: Based on the intercepted radar signal from the transmitting source, the baseband data of the jamming signal is obtained by combining the radiation source element number, signal complex amplitude coefficient, target radar transmission weight, jamming signal two-way propagation delay, radiation source element phase difference, and transmission signal carrier frequency with down-conversion and jamming modulation.

[0006] Further, S3 includes: Based on the radial distance between the radar and the jammer, the minimum range resolution unit of the radar, and the duration of the radar pulse, a mapping relationship between the position of the false target and the frequency offset is constructed. Based on the mapping relationship between the position and frequency offset of the false target, the initial frequency offset data is constrained, and the range-dimensional false target is deployed by combining the baseband data of the interference signal to obtain the range-dimensional false target signal data.

[0007] Furthermore, the expression for the mapping relationship between the false target position and the frequency offset is: ; ; in, This represents the radial distance between the q-th false target and the radar, obtained by pre-setting false target position parameters. This indicates the radial distance between the radar and the jammer, obtained through radar positioning and reconnaissance parameters. B represents the minimum range resolution unit of the radar, B represents the radar signal bandwidth obtained through signal parameter estimation, and c represents the speed of light. This indicates the duration of the radar pulse acquired through signal interception. This represents the frequency offset loaded on the q-th element of the frequency control array.

[0008] Further, S4 includes: Based on the radar transmitted signal wavelength and radar pulse repetition frequency, a mapping relationship between frequency offset and false target velocity is constructed; Based on the mapping relationship between frequency offset and false target velocity, and combined with the range cell interval between the false target and the jammer and the frequency offset folded into the main observation interval, the frequency offset corresponding to the range dimension false target signal data is corrected to obtain the frequency-corrected intermediate signal data. Based on the intermediate signal data after frequency correction, the frequency offset difference between adjacent array elements is constrained to make the position of the false target linearly distributed in the range dimension, thus obtaining two-dimensional false target signal data in range and velocity.

[0009] Furthermore, the frequency offset corresponding to the distance-dimensional false target signal data is corrected, and the expression for the corrected frequency offset is as follows: ; ; ; in, This represents the frequency offset of the q-th array element after correction. This indicates the distance unit interval between the decoy and the jammer. This indicates the distance difference between the preset false target and the jammer. This represents the smallest range-resolution unit of the radar. Indicates the duration of the radar pulse. This represents the velocity of the q-th false target obtained through a preset motion trajectory. This indicates the wavelength of the radar transmitted signal obtained through reconnaissance parameters. The frequency offset folded into the main observation interval is represented by PRF, which represents the radar pulse repetition frequency obtained through signal interception, and n represents the number of pulse folds obtained through the signal processing algorithm.

[0010] Further, S5 includes: The radial distance between the radar and the jammer, the distance between the target and the jammer, and the number of jammer array elements are calculated to obtain the phase modulation amount; By combining frequency offset and phase modulation, phase modulation is performed on the two-dimensional false target signal data of range and velocity, and the time-varying characteristics of the interference signal are controlled so that the target range cell is in the trough of the interference signal, thus obtaining modulated signal data with trough characteristics. By utilizing modulated signal data with trough characteristics, the covariance matrix estimation of the radar receiver is degraded, thereby generating a two-dimensional interference signal resistant to adaptive spatial filtering.

[0011] Furthermore, the expression for the phase modulation amount is: ; in, Indicates the phase modulation amount. This indicates the distance between the target and the jammer, obtained through a preset spatial layout. The radial distance between the jammer and the radar, obtained through radar positioning, is represented by Q, which represents the inherent number of array elements of the jammer, and c represents the speed of light.

[0012] The beneficial effects of this invention are as follows: This invention provides a two-dimensional anti-spatial filtering jamming method based on frequency control array. By using a preset mapping relationship between the position of the false target and the frequency offset, and utilizing initial frequency offset data and baseband data of the jamming signal to deploy range-dimensional false targets, it is possible to accurately deploy false targets in any specified range cell, thereby improving the flexibility of range deception. By correcting the frequency offset based on a preset mapping relationship between the frequency offset and the velocity of the false target, and combining it with the frequency deviation value constraint between array elements, it is possible to flexibly deploy multiple false targets on the range-velocity two-dimensional plane, thereby enhancing the multi-dimensional joint jamming capability. Based on the radial distance between the radar and the jammer, phase modulation is performed, and the time-varying characteristics of the jamming signal are controlled by the frequency offset, so that the target range cell is in the trough of the jamming signal, thereby effectively degrading the covariance matrix estimation of the radar receiver, and finally generating a two-dimensional jamming signal resistant to adaptive spatial filtering, solving the technical problem that traditional deception jamming is difficult to resist spatial filtering. Attached Figure Description

[0013] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein: Figure 1 This is an exemplary flowchart of a two-dimensional anti-spatial filtering interference method based on a frequency control array, as shown in some embodiments of this specification. Figure 2 These are exemplary schematic diagrams of jammers, radars, and target spatial three-dimensional models shown in some embodiments of this specification; Figure 3 This is an exemplary schematic diagram showing the variation of MVDR beam nulls affected by frequency-controlled array main lobe interference signals, according to some embodiments of this specification. Figure 4 This is an exemplary schematic diagram illustrating the variation of output signal-to-interference-plus-noise ratio (SNR) with input SNR under the influence of frequency control array interference signals, according to some embodiments of this specification. Figure 5 This is an exemplary schematic diagram illustrating the change of output signal-to-interference-plus-noise ratio (SINR) with input SINR under the influence of frequency control array interference signals, according to some embodiments of this specification. Figure 6 This is an exemplary schematic diagram comparing DOA estimation under the influence of conventional interference signals and frequency control array interference signals, as shown in some embodiments of this specification. Detailed Implementation

[0014] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0015] Example Figure 1 This is an exemplary flowchart illustrating a two-dimensional spatial filtering interference resistance method based on a frequency-controlled array, according to some embodiments of this specification. Figure 1 As shown, the process includes the following steps. In some embodiments, the process may be executed by a processor.

[0016] S1: Using preset frequency control array parameters, apply frequency offset to each element of the frequency control array to obtain initial frequency offset data.

[0017] Frequency-controlled arrays are antenna array systems used by jammers. Their key feature is the generation of time-varying transmit beams that are dependent on distance and angle, achieved by applying minute frequency offsets between different array elements, thus enabling multi-dimensional jamming. For example, a frequency-controlled array may include multiple transmit antenna elements arranged in a uniform linear pattern with a number of elements Q and an element spacing of d, along with corresponding radio frequency transceiver channels.

[0018] In some embodiments, the processor can obtain the configuration data of the frequency control array by reading the hardware structure configuration specification file or system initialization parameters pre-written by the jamming device.

[0019] Frequency control array parameters are fundamental settings used to configure the operating state and physical structure of the frequency control array. These settings determine the spatial energy distribution characteristics of the jammer's transmitted signal. For example, frequency control array parameters may include hardware attribute information such as the total number of physical array elements, the spatial geometric spacing between adjacent elements, and the antenna gain coefficient.

[0020] In some embodiments, the processor can obtain frequency control array parameter data by calling a system configuration file stored in read-only memory or by receiving control commands from an external console.

[0021] Frequency offset refers to the small frequency change applied to each transmit antenna element in a frequency-controlled array relative to a reference element. This is the core mechanism for frequency-controlled arrays to achieve time-varying beamforming and multi-dimensional deception. For example, frequency offset can include frequency increments or decrements at the Hertz or kilohertz level to change the initial phase of the transmitted signal of each element.

[0022] In some embodiments, the processor can perform mapping relationship calculation through an internally preset frequency offset calculation module and send the result to the numerically controlled oscillator to obtain and apply frequency offset data.

[0023] Initial frequency offset data refers to the set of fundamental frequency offset values ​​assigned to each array element by the jammer when it first intercepts a signal or during the initial operating phase, before undergoing secondary corrections through complex mappings such as velocity dimension. For example, initial frequency offset data may include the initial frequency offset constants of each array element calculated solely based on preset range dimension false target positions and radar range resolution units.

[0024] In some embodiments, the processor can obtain initial frequency offset data by invoking a distance deception initial configuration strategy and formula calculation logic preset in memory.

[0025] S2: The intercepted radar signal from the transmitting source is down-converted and subjected to jamming modulation to obtain the baseband data of the jamming signal.

[0026] The source radar signal refers to the detection electromagnetic wave signal emitted by the enemy or the target radar and propagated to the jammer. It is the original carrier for the jammer to intercept and subsequently modulate the signal. For example, the source radar signal may include a high-frequency radio frequency waveform carrying characteristics such as specific radar pulse width, carrier frequency, pulse repetition frequency, and target radar transmission weight.

[0027] In some embodiments, the processor can intercept and acquire the transmitting source radar signal data through the jammer's intercept receiving antenna and the associated radio frequency front-end amplification and filtering channels. The expression for the transmitting source radar signal is: ; ; ; in, This indicates the intercepted radar signal from the transmitting source. This represents the complex amplitude coefficients of the intercepted signal obtained through quadrature demodulation. This indicates the target radar transmission weight obtained through reconnaissance analysis. This represents the target radar transmitted baseband signal waveform obtained through signal envelope extraction. This indicates the two-way propagation delay of the interference signal. The radial distance between the radar and the jammer is represented by , and c represents the speed of light. This represents the phase difference between the nth radiation source element and the reference element, where n represents the radiation source element number. This represents the element spacing between the transmitting array elements, estimated through reconnaissance parameters. This indicates the angle of arrival of the interference signal obtained through the direction-finding system. t represents the carrier frequency of the transmitted signal; t represents the system sampling time.

[0028] In some embodiments, the expression for the signal data vector received by the radar is: ; in, This represents the vector of signal data received by the radar. This indicates the target direction obtained through target location calculation. The corresponding guide vector, This represents the target complex amplitude obtained through signal processing. This represents the received interference signal vector. This represents the Gaussian white noise vector.

[0029] Interference signal baseband data refers to the low-frequency digital complex signal of an intercepted radio frequency radar signal after being down-converted by a jammer, with the high-frequency carrier removed and preliminary interference modulation information superimposed. For example, interference signal baseband data may include baseband waveform samples of complex digital sequences modulated with false target delay information and containing real and imaginary parts.

[0030] In some embodiments, the processor can acquire the baseband data of the interference signal by performing digital mixing, low-pass filtering, and modulation operations within the digital radio frequency memory on the intercepted high-frequency signal. The expression for the baseband data of the interference signal is: ; in, This represents the baseband data of the interference signal generated by the q-th radiating antenna of the frequency-controlled array jammer. This represents the coefficient of the q-th radiating antenna of the frequency-controlled array jammer, obtained through pre-configured hardware settings. This represents the frequency offset applied to the q-th element of the frequency control array. This indicates the amount of phase modulation applied.

[0031] In some embodiments, the processor can perform down-conversion and interference modulation processing based on the intercepted transmitting source radar signal, combined with the radiation source element number, signal complex amplitude coefficient, target radar transmission weight, interference signal two-way propagation delay, radiation source element phase difference, and transmitting signal carrier frequency, to obtain interference signal baseband data.

[0032] The radiation source element number is a sequential number used to uniquely identify each individual antenna element in a phased array of a target radar transmitter, and is used to resolve the spatial phase difference of the radar signal. For example, the radiation source element number can include a sequence of integer indices that start from 0 and increment sequentially, where the element numbered 0 is usually designated as the reference element for calculating the phase difference.

[0033] In some embodiments, the processor can obtain radiation source element numbering data by performing mathematical inversion analysis on the angle of arrival and spatial distribution characteristics of the intercepted signal using radar reconnaissance equipment.

[0034] The complex amplitude coefficient of a signal is a parameter that characterizes the combined properties of amplitude attenuation and phase change experienced by the intercepted radar signal during its propagation in space. For example, the complex amplitude coefficient can include complex scalar data containing a real part representing amplitude fading and an imaginary part representing phase shift, reflecting the channel characteristics of the signal and the receiver gain state.

[0035] In some embodiments, the processor can obtain signal complex amplitude coefficient data by performing amplitude and phase measurements on the intercepted signal after quadrature demodulation and calculating channel characteristics.

[0036] Target radar transmit weights refer to the amplitude and phase weights assigned to each transmit element in a target radar array in order to form a specific directional transmit beam in space. For example, target radar transmit weights may include amplitude control weights and phase adjustment weights used to control the direction of the transmit main lobe beam and suppress the sidelobe level.

[0037] In some embodiments, the processor can obtain target radar transmission weight data through long-term observation of the target radar beam scanning pattern and array signal processing inversion calculation by an electronic reconnaissance system.

[0038] The two-way propagation delay of a jamming signal refers to the total spatial transmission time required for a target radar signal to travel from the radar antenna to the jammer's receiving antenna, be processed by the jammer, and then propagate back to the radar receiver. For example, the two-way propagation delay of a jamming signal can include the total round-trip flight time of the electromagnetic waves due to the physical spatial distance between the radar and the jammer, typically on the order of microseconds.

[0039] In some embodiments, the processor can derive the two-way propagation delay data of the interference signal by calculating the real-time radial distance between the radar and the jammer and dividing it by twice the speed of light.

[0040] Radiation source element phase difference refers to the initial phase angle difference between elements at different physical locations in a target radar transmitting array and a designated reference element when transmitting the same signal. For example, radiation source element phase difference can include radian or angular values ​​resulting from differences in element spacing and the electrical axis pointing angle requirements of the target radar beam.

[0041] In some embodiments, the processor can obtain radiation source element phase difference data by analyzing the target radar's angle of arrival, transmitted signal wavelength, and estimated element spacing parameters to perform geometric trigonometric function calculations.

[0042] The carrier frequency of a transmitted signal is the center frequency of the fundamental high-frequency carrier carried by a target radar in its transmitted signal, and it is one of the fundamental characteristics of radar radio frequency signals. For example, the carrier frequency of a transmitted signal can include specific center frequency values ​​such as 10 GHz in the X-band or 3 GHz in the S-band, which determines the physical wavelength of the electromagnetic wave.

[0043] In some embodiments, the processor can obtain the carrier frequency data of the transmitted signal by performing fast Fourier transform spectrum analysis and peak envelope search on the intercepted radar signal.

[0044] S3: Based on the preset mapping relationship between the position and frequency offset of the false target, the range-dimensional false target is deployed using the initial frequency offset data and the baseband data of the interference signal to obtain the range-dimensional false target signal data.

[0045] The mapping relationship between false target position and frequency offset refers to the mathematical transformation rule between the required array element frequency offset and the target position in a frequency-controlled array system in order to generate a desired false target in a specific range dimension. For example, the mapping relationship between false target position and frequency offset can include linear or nonlinear correspondence equations constructed based on the radar's minimum range resolution element, radar pulse duration, and the radial range deviation of the false target.

[0046] In some embodiments, the processor can obtain the mapping relationship data between the position and frequency offset of the false target by consulting a pre-stored tactical parameter conversion table or by calling the internally set algorithm logic derivation.

[0047] Range-dimensional decoy signal data is a set of interference signals that, after initial frequency offset modulation, can induce range illusions in a radar receiver, but has not yet produced additional deceptive characteristics in the velocity dimension. For example, range-dimensional decoy signal data may include a baseband modulated waveform sample matrix that causes a fixed-cell bias in the ranging result after radar matched filtering.

[0048] In some embodiments, the processor can acquire range-dimensional false target signal data by loading the acquired initial frequency offset data into the interference signal baseband data and performing digital complex multiplication.

[0049] In some embodiments, the processor can construct a mapping relationship between the position and frequency offset of the false target based on the radial distance between the radar and the jammer, the minimum range resolution unit of the radar, and the duration of the radar pulse; based on the mapping relationship between the position and frequency offset of the false target, constrain the initial frequency offset data, and combine it with the baseband data of the jamming signal to deploy range-dimensional false targets and obtain range-dimensional false target signal data.

[0050] The radial distance between a radar and a jammer refers to the straight-line physical span between the phase center of the target radar antenna and the phase center of the frequency-controlled array jammer's receiving antenna. For example, the radial distance between the radar and the jammer can include an absolute distance scalar value in meters or kilometers, which directly affects the signal propagation delay.

[0051] In some embodiments, the processor can obtain radial distance data between the radar and the jammer by calculating the passive positioning and reconnaissance system built into the jammer or by obtaining battlefield situation information shared through a cooperative combat network.

[0052] The minimum range resolution unit of a radar system refers to the smallest radial distance difference that allows the system to effectively distinguish two adjacent targets located in the same direction but at different distances. For example, the minimum range resolution unit of a radar system can include a specific spatial resolution range from tens of meters to hundreds of meters, and it is uniquely determined by the transmission bandwidth of the radar signal.

[0053] In some embodiments, the processor can estimate the effective bandwidth of the radar signal through electronic reconnaissance and obtain the minimum range resolution unit data of the radar by performing formula calculation and division operations in combination with the speed of light.

[0054] Radar pulse duration refers to the absolute time span of a complete radio frequency pulse waveform emitted by a target radar, from the rising edge of the energy pulse to the falling edge of the energy pulse; it is often referred to as pulse width. For example, radar pulse duration can include time length values ​​in the microsecond or nanosecond range, such as 10 microseconds or 50 microseconds.

[0055] In some embodiments, the processor can acquire radar pulse duration data by performing digital detection and amplitude threshold decision measurement on the radio frequency envelope of the intercepted radar signal.

[0056] In some embodiments, the expression for the mapping relationship between the dummy target position and the frequency offset is: ; ; in, This represents the radial distance between the q-th false target and the radar, obtained by pre-setting false target position parameters. This indicates the radial distance between the radar and the jammer, obtained through radar positioning and reconnaissance parameters. B represents the minimum range resolution unit of the radar, B represents the radar signal bandwidth obtained through signal parameter estimation, and c represents the speed of light. This indicates the duration of the radar pulse acquired through signal interception. This represents the frequency offset loaded on the q-th element of the frequency control array.

[0057] S4: Based on the preset mapping relationship between frequency offset and false target velocity, the frequency offset corresponding to the range-dimensional false target signal data is corrected to obtain range-velocity two-dimensional false target signal data.

[0058] The mapping relationship between frequency offset and false target velocity refers to the correspondence between the corrected frequency offset amount and the false velocity value required to produce a specific false velocity deception effect in the velocity dimension (Doppler domain). For example, the mapping relationship between frequency offset and false target velocity may include frequency shift calculation conversion formulas involving target radar signal wavelength, pulse repetition frequency, and folding frequency parameters.

[0059] In some embodiments, the processor can obtain the mapping relationship data between frequency offset and false target velocity by reading the internally set deception motion velocity parameter library and substituting it into the Doppler conversion physical model.

[0060] Two-dimensional range-velocity decoy signal data is generated by simultaneously performing frequency offset modulation correction in both the range and velocity dimensions, and after being constrained by the frequency offset values ​​of adjacent array elements, it can produce a signal sequence of decoys with specific positions and Doppler characteristics. For example, two-dimensional range-velocity decoy signal data can include a digital complex signal data stream that incorporates decoy delay, Doppler frequency shift, and spatial time-varying distribution characteristics.

[0061] In some embodiments, the processor can obtain range-velocity two-dimensional false target signal data by performing array element linear distribution difference constraint processing on the frequency-corrected intermediate signal data.

[0062] In some embodiments, the processor can construct a mapping relationship between frequency offset and false target velocity based on the radar transmitted signal wavelength and radar pulse repetition frequency; based on the mapping relationship between frequency offset and false target velocity, combined with the range cell spacing between the false target and the jammer and the frequency offset folded into the main observation interval, the processor corrects the frequency offset corresponding to the range dimension false target signal data to obtain frequency-corrected intermediate signal data; based on the frequency-corrected intermediate signal data, the processor constrains the frequency offset difference between adjacent array elements to make the position of the false target in the range dimension linearly distributed, thus obtaining range-velocity two-dimensional false target signal data.

[0063] The range cell interval between the decoy and the jammer refers to the relative position offset in grids between the planned, generated decoy target position and the jammer's actual physical position, measured in the radar's smallest range resolution cell. For example, the range cell interval between the decoy and the jammer can include positive or negative integer data, representing the number of range resolution cells ahead or behind the jammer's range by the decoy target, respectively.

[0064] In some embodiments, the processor can obtain the range cell interval data between the false target and the jammer by calculating the physical absolute distance difference between the set false target and the jammer, dividing it by the minimum range resolution cell of the radar, and then rounding it up.

[0065] In some embodiments, the expression for the frequency offset difference constraint between adjacent array elements is: ; in, This represents the frequency offset difference between adjacent array elements, where q represents the jammer array element number; and n represents a selected positive integer constant. Indicates the duration of the radar pulse.

[0066] In some embodiments, the frequency offset corresponding to the distance dimension false target signal data is corrected, and the expression for the corrected frequency offset is: ; ; ; in, This represents the frequency offset of the q-th array element after correction. This indicates the distance unit interval between the decoy and the jammer. This indicates the distance difference between the preset false target and the jammer. This represents the smallest range-resolution unit of the radar. Indicates the duration of the radar pulse. This represents the velocity of the q-th false target obtained through a preset motion trajectory. This indicates the wavelength of the radar transmitted signal obtained through reconnaissance parameters. The frequency offset folded into the main observation interval is represented by PRF, which represents the radar pulse repetition frequency obtained through signal interception, and n represents the number of pulse folds obtained through the signal processing algorithm.

[0067] The frequency-corrected intermediate signal data is the transitional state signal data generated during the process of creating a two-dimensional joint false target. Only the frequency offset correction based on single-element velocity mapping has been completed, but the relative relationship constraints between adjacent elements have not yet been applied. For example, the frequency-corrected intermediate signal data may include intermediate computational matrix with added velocity folding frequency compensation, but which does not yet possess specific beam time-varying characteristics in the spatial domain.

[0068] In some embodiments, the processor can obtain frequency-corrected intermediate signal data by applying a frequency offset correction calculated based on the velocity mapping to the range-dimensional dummy target signal data.

[0069] S5: Utilizing the radial distance between the radar and the jammer, phase modulation is performed on the range and velocity two-dimensional false target signal data to generate an anti-airspace filtered two-dimensional jamming signal, thus completing the anti-airspace filtered two-dimensional jamming.

[0070] Anti-spatial filtering two-dimensional jamming signals are radio frequency (RF) interference waveforms ultimately generated by the jamming system. These waveforms can both create deceptive false targets in the range-velocity two-dimensional plane of the radar receiver and completely disable adaptive spatial filtering algorithms such as radar MVDR through their time-varying beam characteristics. For example, anti-spatial filtering two-dimensional jamming signals can include multiple transmitted RF signal streams that have been digitally synthesized, have a specific spatial energy null distribution, and have been up-converted to the RF band.

[0071] In some embodiments, the processor can acquire anti-spatial-filtered two-dimensional interference signal data by performing digital-to-analog conversion, radio frequency up-conversion, and power amplification on the modulated signal data with trough characteristics.

[0072] In some embodiments, the optimized solution expression for the adaptive spatial filtering interference weights is: ; ; ; Where w represents the adaptive spatial filtering interference weights that need to be solved. Let E represent the interference plus noise covariance matrix, E represent the expectation operation, H represent the conjugate transpose, and the constraints be... This is used to ensure that the target direction signal gain is 1.

[0073] In some embodiments, the processor can calculate the radial distance between the radar and the jammer, the distance between the target and the jammer, and the number of jammer array elements to obtain the phase modulation amount; by combining the frequency offset and the phase modulation amount, the processor performs phase modulation on the range-velocity two-dimensional false target signal data, controls the time-varying characteristics of the jamming signal so that the target range element is in the trough of the jamming signal, and obtains modulated signal data with trough characteristics; using the modulated signal data with trough characteristics, the processor degrades the covariance matrix estimation of the radar receiver and generates a two-dimensional jamming signal resistant to adaptive spatial filtering.

[0074] The distance between the target and the jammer refers to the physical straight-line distance between the real target to be detected, which needs to be protected, and the frequency-controlled array jammer performing the deception and cover mission. For example, the distance between the target and the jammer can include Euclidean distance scalar data between the center coordinates of the real target and the center coordinates of the jammer in a three-dimensional coordinate system. In some embodiments, the processor can calculate and obtain the distance data between the target and the jammer through the inertial navigation system of the jamming carrier and real-time positioning information exchanged via data link between the real target and the jammer.

[0075] The number of jamming elements refers to the total number of antenna physical units in a frequency-controlled array jammer antenna array system that can independently control and transmit electromagnetic waves. For example, the number of jamming elements can include predetermined fixed positive integer data, such as 8 antenna elements or 16 antenna elements.

[0076] In some embodiments, the processor can obtain the number of jammer array elements by reading the self-test status report of the jammer hardware device or the factory configuration file of the system firmware. A spatial coordinate scene diagram of the target radar, the target to be detected, and the frequency control array jammer is shown below. Figure 2 As shown.

[0077] Phase modulation refers to the additional spatial phase control value applied to the interference signals of each element of the frequency control array, based on the existing frequency offset, in order to counteract adaptive spatial filtering. For example, phase modulation may include the phase angle compensation difference calculated using spatial triangular distance relationships to disrupt the coherence of the signal covariance matrix at the target range cell.

[0078] In some embodiments, the processor can derive phase modulation data by substituting the spatial relative geometric distance parameters of the jammer, the target radar, and the protected target into a preset algorithm model. For example... Figure 3 As shown, a comparison diagram of the interference signal power near the target range cell before and after phase modulation is presented. It can be seen from the diagram that after phase modulation, the target range cell is located at the trough of the interference signal power, indicating that the interference signal after phase modulation can degrade the radar's estimation performance of the covariance matrix of the interference signal.

[0079] In some embodiments, the expression for the phase modulation amount is: ; in, Indicates the phase modulation amount. This indicates the distance between the target and the jammer, obtained through a preset spatial layout. The radial distance between the jammer and the radar, obtained through radar positioning, is represented by Q, which represents the inherent number of array elements of the jammer, and c represents the speed of light.

[0080] Modulated signal data with trough characteristics are signal characteristic data in which the spatial energy distribution of the transmitted signal exhibits a minimum power value at the range cell of the protected target after joint modulation by frequency offset and phase modulation, i.e., null or trough state. For example, modulated signal data with trough characteristics may include a spatially non-stationary baseband signal vector matrix that degrades the data quality of radar receiver sampling points and thus leads to the failure of covariance matrix estimation.

[0081] In some embodiments, the expression for estimating the covariance matrix of the radar receiver is: ; in, This represents the estimate of the radar receiver covariance matrix calculated using snapshot data. This represents the k-th snapshot data obtained by sampling around the target range cell, N represents the number of radar receiving array antennas obtained by radar hardware parameter estimation, and k represents the snapshot data index.

[0082] In some embodiments, the processor can precisely apply a specifically calculated phase modulation amount to the two-dimensional dummy target signal data of range and velocity, and use the principle of spatial signal cancellation to obtain modulated signal data with trough characteristics.

[0083] In some embodiments, to ensure the feasibility of the technical solution provided by the present invention in actual engineering, the value ranges of some physical constants and configuration parameters involved in the formula are explained. Specifically: This indicates the duration of the radar pulse, and its value typically ranges from [value range missing]. to Between these ranges, for example, a value that can be taken in a specific simulation application. ; This indicates the carrier frequency of the transmitted signal, and its value range can cover typical radar operating frequency bands, such as the X-band. to For example, the possible values ​​are ; This indicates the number of jamming array elements, and its value range is an even positive integer greater than or equal to 4, for example, it can be configured as 8 or 16; or This represents the element spacing. To avoid grating lobe effects, its value is usually set to be no greater than half the wavelength of the transmitted signal. ; When representing the number of pulse folds or used as a positive integer constant in the formula difference constraint, its value range is the set of positive integers. The number of snapshots in the covariance matrix estimation formula, i.e. Its value range must be greater than or equal to twice the number of radar receiving array antennas N to ensure the non-singularity of the matrix and the estimation accuracy.

[0084] like Figure 4The diagram shows the beam pattern of MVDR adaptive spatial filtering after the jamming signal reaches the radar receiver. A smaller jammer frequency offset produces a shallower beam null, indicating lower suppression capability. A larger jammer frequency offset produces a deeper beam null, indicating relatively better jamming suppression capability. This phenomenon occurs because as the frequency offset increases, the period of the jamming signal decreases, resulting in fewer low-quality sampling points near the target range cell, thus reducing the jamming effect. It is noteworthy that the beam nulls of both large and small frequency offset jamming signals are shallower than those of conventional phased array deception jamming algorithms, indicating that MVDR is more difficult to suppress them.

[0085] like Figure 5 The figure shows a comparison of the output signal-to-interference-plus-noise ratio (SIR) of the interference signal generated by this algorithm after passing through MVDR under different conditions, with a Monte Carlo simulation number of 15,000. The simulation results show that, under the same number of snapshots, regardless of whether a small or large jammer frequency offset is set, the output SIR of the interference algorithm proposed in this section is at least 4 dB lower than that of traditional deception jamming methods.

[0086] like Figure 6 As shown, the results of receiver matched filtering after spatial filtering are compared under the influence of traditional interference signals and frequency control array interference signals. It can be seen that the output power of the traditional deception interference algorithm is about 8dB lower than that of the algorithm proposed in this invention. This proves that the present invention has a greater ability to be suppressed by the adaptive algorithm than the traditional deception interference, and has a significant advantage in resisting spatial filtering.

Claims

1. A two-dimensional interference suppression method based on frequency control array for spatial filtering, characterized in that, include: S1: Using preset frequency control array parameters, apply frequency offset to each element of the frequency control array to obtain initial frequency offset data; S2: The intercepted radar signal from the transmitting source is down-converted and subjected to jamming modulation to obtain the baseband data of the jamming signal; S3: Based on the preset mapping relationship between the position and frequency offset of the false target, the range-dimensional false target is deployed using the initial frequency offset data and the baseband data of the interference signal to obtain the range-dimensional false target signal data; S4: Based on a preset mapping relationship between frequency offset and false target velocity, the frequency offset corresponding to the range-dimensional false target signal data is corrected to obtain range-velocity two-dimensional false target signal data; S4 includes: Based on the radar transmitted signal wavelength and radar pulse repetition frequency, a mapping relationship between frequency offset and false target velocity is constructed; Based on the mapping relationship between frequency offset and false target velocity, and combined with the range cell interval between the false target and the jammer and the frequency offset folded into the main observation interval, the frequency offset corresponding to the range dimension false target signal data is corrected to obtain the frequency-corrected intermediate signal data. Based on the intermediate signal data after frequency correction, the frequency offset difference between adjacent array elements is constrained so that the position of the false target in the range dimension is linearly distributed, thus obtaining two-dimensional false target signal data in range and velocity. S5: Utilizing the radial distance between the radar and the jammer, phase modulation is performed on the range and velocity two-dimensional false target signal data to generate an anti-spatial-domain filtered two-dimensional jamming signal, thus completing the anti-spatial-domain filtered two-dimensional jamming; S5 includes: The radial distance between the radar and the jammer, the distance between the target and the jammer, and the number of jammer array elements are calculated to obtain the phase modulation amount; By combining frequency offset and phase modulation, phase modulation is performed on the two-dimensional false target signal data of range and velocity, and the time-varying characteristics of the interference signal are controlled so that the target range cell is in the trough of the interference signal, thus obtaining modulated signal data with trough characteristics. By utilizing modulated signal data with trough characteristics, the covariance matrix estimation of the radar receiver is degraded, thereby generating a two-dimensional interference signal resistant to adaptive spatial filtering.

2. The two-dimensional interference suppression method based on frequency control array according to claim 1, characterized in that, S2 includes: Based on the intercepted radar signal from the transmitting source, the baseband data of the jamming signal is obtained by combining the radiation source element number, signal complex amplitude coefficient, target radar transmission weight, jamming signal two-way propagation delay, radiation source element phase difference, and transmission signal carrier frequency with down-conversion and jamming modulation.

3. The two-dimensional interference suppression method based on frequency control array according to claim 1, characterized in that, S3 includes: Based on the radial distance between the radar and the jammer, the minimum range resolution unit of the radar, and the duration of the radar pulse, a mapping relationship between the position of the false target and the frequency offset is constructed. Based on the mapping relationship between the position and frequency offset of the false target, the initial frequency offset data is constrained, and the range-dimensional false target is deployed by combining the baseband data of the interference signal to obtain the range-dimensional false target signal data.

4. The two-dimensional interference suppression method based on frequency control array according to claim 3, characterized in that, The expression for the mapping relationship between the dummy target position and the frequency offset is: ； ； in, This represents the radial distance between the q-th false target and the radar, obtained by pre-setting false target position parameters. This indicates the radial distance between the radar and the jammer, obtained through radar positioning and reconnaissance parameters. B represents the minimum range resolution unit of the radar, B represents the radar signal bandwidth obtained through signal parameter estimation, and c represents the speed of light. This indicates the duration of the radar pulse acquired through signal interception. This represents the frequency offset loaded on the q-th element of the frequency control array.

5. The two-dimensional interference suppression method based on frequency control array according to claim 1, characterized in that, The frequency offset corresponding to the distance-dimensional false target signal data is corrected, and the expression for the corrected frequency offset is as follows: ； ； ； in, This represents the frequency offset of the q-th array element after correction. This indicates the distance unit interval between the decoy and the jammer. This indicates the distance difference between the preset false target and the jammer. This represents the smallest range-resolution unit of the radar. Indicates the duration of the radar pulse. This represents the velocity of the q-th false target obtained through a preset motion trajectory. This indicates the wavelength of the radar transmitted signal obtained through reconnaissance parameters. The frequency offset folded into the main observation interval is represented by PRF, which represents the radar pulse repetition frequency obtained through signal interception, and n represents the number of pulse folds obtained through the signal processing algorithm.

6. The two-dimensional interference suppression method based on frequency control array according to claim 1, characterized in that, The expression for the phase modulation amount is: ； in, Indicates the phase modulation amount. This indicates the distance between the target and the jammer, obtained through a preset spatial layout. The radial distance between the jammer and the radar, obtained through radar positioning, is represented by Q, which represents the inherent number of array elements of the jammer, and c represents the speed of light.

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