Radar sidelobe interference resisting method based on electronic reconnaissance

Abstract

The invention discloses a radar sidelobe interference resisting method based on electronic reconnaissance, and the method comprises the steps: setting an electronic reconnaissance channel on a radar, and obtaining an interference signal parameter through a frequency domain and time domain signal analysis method; configuring a plurality of groups of dual-polarized auxiliary antennas, screening an interference cancellation channel matched with an interference signal from a plurality of groups of dual-polarized auxiliary channels based on an interference signal parameter obtained by an electronic reconnaissance channel, and performing adaptive polarization domain filtering on a main beam; the method comprises the following steps: simultaneously sampling main beam synthesis data and auxiliary channel data by using a radar, and calculating weights of a main channel and an auxiliary channel according to interference signal parameter information measured by an electronic reconnaissance channel; and performing sidelobe cancellation point by point by using the calculated weight. According to the embodiment of the invention, an integrated design of electronic reconnaissance and interference countermeasure is adopted, related information of interference is obtained through an electronic reconnaissance technology, then selection of an auxiliary channel and calculation of a self-adaptive optimal weight are carried out, and the anti-sidelobe interference performance of the radar is improved.

Description

Technical Field

[0001] This invention relates to the field of radar anti-jamming technology, and in particular to a radar anti-sidelobe jamming method based on electronic reconnaissance. Background Technology

[0002] In radar systems, sidelobe cancellation is frequently used to suppress sidelobe interference. Active interference signals have a low probability of entering through the main lobe of the receiving antenna, but are highly likely to enter through the sidelobes. The interference signal received by the auxiliary antenna is used to suppress directional interference entering through the sidelobes of the main antenna. The signal from the auxiliary antenna is weighted and then subtracted from the interference signal received by the main antenna, minimizing the interference output power of the main channel and thus achieving interference cancellation.

[0003] In practical radar applications of sidelobe cancellation, its performance is affected by multiple factors, including the number of interference sources, interference type, interference polarization, interference-to-noise ratio (IRR), and interference bandwidth. Achieving optimal interference suppression ratio through sidelobe cancellation is one of the key challenges. Generally, when using sidelobe cancellation, there is no prior information about the interference signal; the number of interference sources, interference type, and interference polarization are usually unknown, resulting in suboptimal sidelobe cancellation performance.

[0004] Therefore, it is necessary to improve one or more of the problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that this section is intended to provide background or context for the technical solutions of this disclosure as set forth in the claims. The description herein does not constitute an admission that it is prior art simply because it is included in this section. Summary of the Invention

[0006] The purpose of this invention is to provide a radar anti-sidelobe interference method based on electronic reconnaissance, thereby overcoming, at least to some extent, one or more problems caused by the limitations and defects of related technologies.

[0007] This invention provides a radar anti-sidelobe interference method based on electronic reconnaissance, comprising: S1, set up an electronic reconnaissance channel on the radar, and obtain interference signal parameters through frequency domain and time domain signal analysis methods; S2, configure multiple sets of dual-polarized auxiliary antennas, based on the interference signal parameters obtained by the electronic reconnaissance channel, select the interference cancellation channel that matches the interference signal from the multiple sets of dual-polarized auxiliary channels, and perform adaptive polarization domain filtering on the main beam; S3 utilizes radar to simultaneously sample the main beam composite data and the auxiliary channel data, and calculates the weights of the main channel and the auxiliary channel based on the interference signal parameter information measured by the electronic reconnaissance channel; S4 uses the calculated weights to perform sidelobe cancellation point by point.

[0008] In this invention, in S1, the interference signal parameters include: carrier frequency, bandwidth, polarization information, interference-to-noise ratio, pulse width, angle, and type.

[0009] In this invention, S1 includes the following specific steps: S11, set up an electronic reconnaissance channel on the radar, and use the electronic reconnaissance channel to compare the collected signals with the primary interference threshold to determine whether there is interference; S12, In the presence of interference, the interference signal parameters are calculated using frequency domain and time domain signal analysis methods; S13. Analyze the interference signal parameters to obtain the number of interference signals. Based on the comparison between the number of interference signals and the number of auxiliary channels, determine whether the interference signals can be canceled.

[0010] In this invention, S2 includes the following specific steps: S21, determine the type of interference based on the polarization information, and select the corresponding auxiliary channel based on the type of interference; S22, polarization filtering is performed on the interference signal based on the polarization information.

[0011] In this invention, step S21, the process of determining the interference type based on the polarization information, includes: When the auxiliary polarization angle is less than 45 degrees, the interference type is determined to be horizontal polarization interference, and the auxiliary channel should be mainly selected as the horizontal polarization channel. When the auxiliary polarization angle is greater than 45 degrees, the interference type is determined to be vertical polarization interference, and the auxiliary channel should be mainly selected based on the vertical polarization channel.

[0012] In this invention, S3 includes the following specific steps: S31, Calculate the autocorrelation matrix of the auxiliary channel data based on the interference signal parameter information measured by the electronic reconnaissance channel; S32, calculate the cross-correlation matrix of the main and auxiliary channel data; S33. Invert the autocorrelation matrix, multiply the resulting inverse matrix with the cross-correlation matrix to obtain the adaptive optimal weights for the main channel and auxiliary channel.

[0013] In this invention, S4 includes: using adaptive optimal weights to perform amplitude weighting and phase weighting on the signals of the main channel and the auxiliary channel, outputting a vector sum signal, completing interference polarization matching of the auxiliary channel, thereby performing sidelobe cancellation point by point.

[0014] The technical solution provided by this invention may include the following beneficial effects: The present invention discloses a radar anti-sidelobe interference method based on electronic reconnaissance, which adopts an integrated design of electronic reconnaissance and jamming countermeasures. Through electronic reconnaissance technology, relevant information on jamming is obtained, and then auxiliary channels are selected and adaptive optimal weights are calculated to improve the radar's anti-sidelobe interference performance. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] Figure 1 A flowchart illustrating a radar anti-sidelobe interference method based on electronic reconnaissance in an exemplary embodiment of this disclosure is shown. Figure 2 A schematic diagram illustrating the integrated design of electronic reconnaissance and anti-jamming in an exemplary embodiment of this disclosure is shown; Figure 3 This diagram illustrates the joint sidelobe cancellation in the spatial domain and polarization domain in an exemplary embodiment of this disclosure. Figure 4 An AR diagram of a radar in an exemplary embodiment of this disclosure is shown. Detailed Implementation

[0017] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0018] Furthermore, the accompanying drawings are merely illustrative diagrams of embodiments of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0019] This example implementation first provides a radar anti-sidelobe interference method based on electronic reconnaissance. Please refer to [reference needed]. Figures 1-3 This method may include: S1-S4. Specifically: S1, set up an electronic reconnaissance channel on the radar, and obtain interference signal parameters through frequency domain and time domain signal analysis methods; S2, configure multiple sets of dual-polarized auxiliary antennas, based on the interference signal parameters obtained by the electronic reconnaissance channel, select the interference cancellation channel that matches the interference signal from the multiple sets of dual-polarized auxiliary channels, and perform adaptive polarization domain filtering on the main beam; S3 utilizes radar to simultaneously sample the main beam composite data and the auxiliary channel data, and calculates the weights of the main channel and the auxiliary channel based on the interference signal parameter information measured by the electronic reconnaissance channel; S4 uses the calculated weights to perform sidelobe cancellation point by point.

[0020] In this embodiment, an integrated design of electronic reconnaissance and jamming countermeasures is adopted. Electronic reconnaissance technology is used to obtain relevant information about jamming, and then auxiliary channels are selected and adaptive optimal weights are calculated to improve the radar's anti-sidelobe jamming performance.

[0021] The specific process of each step in the above embodiments will be described below.

[0022] S1, in actual radar combat use, during adaptive sidelobe cancellation, the basic parameters of the interference can be estimated, providing a basis for the selection of auxiliary channels and the calculation of adaptive optimal weights, thereby improving the radar's anti-sidelobe interference performance. Therefore, this application designs opposing electronic reconnaissance channels on the radar. The interference reconnaissance channel uses frequency domain and time domain signal analysis methods to obtain interference signal parameter information, providing a basis for interference cancellation.

[0023] S1 includes the following specific steps: S11, set up an electronic reconnaissance channel on the radar, and use the electronic reconnaissance channel to compare the collected signals with the primary interference threshold to determine whether there is interference, specifically whether there is suppression interference.

[0024] S12, In the presence of interference, the parameters of the interference signal are calculated using frequency and time domain signal analysis methods. Specifically, the interference signal is segmented and subjected to FFT, and the power spectrum of the interference signal is smoothed using the following formula:

[0025] in, R(l) The spectrum of the interference signal after segmented FFT. W To smooth the window width, Rs(k) This is the smoothed power spectrum.

[0026] set up Rs(k) The maximum amplitude value is Rs(k0) Find Rs(k) All values ​​greater than 0.5 Rs(k0) By observing the spectral lines, an estimated value for the 3dB bandwidth of the interference signal can be calculated.

[0027] Estimated center frequency We obtain it from the following formula:

[0028] in, This represents the corresponding frequency resolution.

[0029] S13. Analyze the interference signal parameters to obtain the number of interference signals. Based on the comparison between the number of interference signals and the number of auxiliary channels, determine whether the interference signals can be canceled.

[0030] The number of interference signals can be determined by the number of center frequencies. When the detected number of interference signals is less than the number of auxiliary channels, the interference signal can be canceled. When the number of interference signals is greater than the number of auxiliary channels, not enough nulls can be formed to cancel the interference sources, and the system's sidelobe cancellation performance will be poor.

[0031] S2. Jammers typically employ polarization-based jammers, allowing for selectable polarization of the jamming signal. Single-polarization auxiliary antennas cannot perfectly match the polarization of the jamming signal, thus failing to effectively cancel sidelobe interference. Therefore, the radar in this application adopts an integrated design for electronic reconnaissance and sidelobe cancellation. Electronic reconnaissance utilizes an independent channel, while the auxiliary channel incorporates four sets of dual-polarization auxiliary antennas. Based on the interference parameters measured by the electronic reconnaissance channel, the radar selects an interference cancellation channel from the four dual-polarization auxiliary channels, adaptively performing polarization domain filtering on the main beam to suppress interference signals with specific polarization characteristics.

[0032] S2 includes the following specific steps: S21, determine the type of interference based on the polarization information, and select the corresponding auxiliary channel based on the type of interference.

[0033] Radar based on polarization ratio Determine the polarization information of the interference, polarization ratio It describes the polarization information of electromagnetic waves:

[0034] in, and These represent the horizontal polarization component and the cross-polarization component, respectively. For polarization auxiliary angle, ; For polarization phase angle, j represents the imaginary unit.

[0035] When polarization auxiliary angle Less than 45 degrees, horizontal polarization component Larger cross-polarization components If the interference is relatively small, it can be determined that the interference is horizontally polarized, and the auxiliary channel should be mainly selected based on the horizontally polarized channel; when the polarization auxiliary angle is small... Greater than 45 degrees, horizontal polarization component Smaller cross-polarization components The interference is relatively large, indicating that it is vertically polarized. Therefore, the auxiliary channel should be mainly selected based on the vertically polarized channel.

[0036] S22, polarization filtering is performed on the interference signal based on the polarization information.

[0037] S3, the radar simultaneously samples the beamforming data of the main channel and the data of the auxiliary channel, and calculates the weighting coefficients of the main channel and the auxiliary channel based on the interference parameters such as carrier frequency and bandwidth of the interference signal measured by the electronic reconnaissance channel.

[0038] S3 includes the following specific steps: S31. Calculate the autocorrelation matrix of the auxiliary channel data based on the interference signal parameter information measured by the electronic reconnaissance channel.

[0039] S32, calculate the cross-correlation matrix of the main and auxiliary channel data.

[0040] S33. Invert the autocorrelation matrix, multiply the resulting inverse matrix with the cross-correlation matrix to obtain the adaptive optimal weights for the main channel and auxiliary channel.

[0041] Specifically, calculate the autocorrelation matrix of the auxiliary channel data:

[0042] In the formula, The sampled value at time t of the m-th auxiliary channel is represented by a complex number, containing both amplitude and phase information of the signal; n is the number of sampling points. This indicates the conjugate operation.

[0043] Calculate the cross-correlation matrix of the primary and secondary channel data:

[0044] In the formula, This represents the conjugate operation of the main channel signal.

[0045] Invert the autocorrelation matrix R, and multiply the inverse matrix by the cross-correlation matrix P to obtain the adaptive optimal weight vector. W is the optimal weight matrix for the 8 auxiliary channels. The adaptive optimal weights W are calculated according to the following formula:

[0046] When the bandwidth of the interference signal is wide, the sidelobe cancellation performance is worse. Therefore, the optimal weight must be calculated differently for each frequency point. Calculating the weight for only one frequency may increase the cancellation error.

[0047] S4 utilizes adaptive optimal weights to perform amplitude and phase weighting on the signals of the main and auxiliary channels, outputting a vector sum signal to complete interference polarization matching of the auxiliary channel, thereby performing sidelobe cancellation point by point:

[0048] in, This represents the final output signal after sidelobe cancellation; This indicates the real-time input signal of the main channel; Let be the adaptive optimal weight for the i-th auxiliary channel. t represents the real-time input signal of the i-th auxiliary channel; t is the time variable.

[0049] Using the method described in this application, a performance verification experiment on sidelobe cancellation was conducted using a physical radar device. Two interference sources were placed at the azimuths of the radar's first and second sidelobes, respectively, releasing different types of interference. Figure 4 As shown, 4(a) is the AR image without sidelobe cancellation by the radar, and 4(b) is the AR image with sidelobe cancellation by the radar. From Figure 4 It can be seen that after adopting the method of this application, the interference suppression capability against sidelobe interference is stronger. While suppressing interference, the signal of the target echo is preserved, which improves the radar's ability to counter interference of different polarizations. The interference suppression ratio is above 20dB.

[0050] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A radar anti-sidelobe jamming method based on electronic reconnaissance, characterized in that, The method comprises the following steps: S1, setting an electronic reconnaissance channel on the radar, obtaining the interference signal parameters through the frequency domain and time domain signal analysis method; S2, configuring multiple groups of dual-polarized auxiliary antennas, screening the interference cancellation channels matched with the interference signal from the multiple groups of dual-polarized auxiliary channels based on the interference signal parameters obtained by the electronic reconnaissance channel, and performing adaptive polarization domain filtering on the main beam; S3, simultaneously sampling the data of the main beam synthesis channel and the auxiliary channel by using the radar, and calculating the weight values of the main channel and the auxiliary channel according to the interference signal parameter information measured by the electronic reconnaissance channel; S4, using the calculated weight values to perform sidelobe cancellation point by point.

2. The radar anti-sidelobe jamming method based on electronic reconnaissance according to claim 1, characterized in that, In S1, the interference signal parameters include carrier frequency, bandwidth, polarization information, signal-to-noise ratio, pulse width, angle and type.

3. The radar anti-sidelobe jamming method based on electronic reconnaissance according to claim 1, characterized in that, S1 comprises the following specific steps: S11, setting an electronic reconnaissance channel on the radar, and comparing the collected signals with the primary interference threshold by using the electronic reconnaissance channel to determine whether there is interference; S12, in the case of interference, calculating the interference signal parameters through the frequency domain and time domain signal analysis method; S13, using the interference signal parameters to analyze the number of interferences, and determining whether the interference signal can be cancelled according to the comparison result of the number of interferences and the number of auxiliary channels.

4. The radar anti-sidelobe jamming method based on electronic reconnaissance according to claim 2, characterized in that, S2 comprises the following specific steps: S21, judging the interference type according to the polarization information, and selecting the corresponding auxiliary channel according to the interference type; S22, performing polarization filtering on the interference signal according to the polarization information.

5. The radar anti-sidrelobbing method based on electronic reconnaissance according to claim 1, characterized in that, In S21, the process of judging the interference type according to the polarization information comprises: When the polarization auxiliary angle is less than 45 degrees, it is judged that the interference type is horizontal polarization interference, and the auxiliary channel is mainly selected as a horizontal polarization channel; When the polarization auxiliary angle is greater than 45 degrees, it is judged that the interference type is vertical polarization interference, and the auxiliary channel is mainly selected as a vertical polarization channel.

6. The radar anti-sidrelobbing jamming method based on electronic reconnaissance according to claim 1, characterized in that, S3 comprises the following specific steps: S31, calculating the autocorrelation matrix of the auxiliary channel data according to the interference signal parameter information measured by the electronic reconnaissance channel; S32, calculating the cross-correlation matrix of the main and auxiliary channel data; S33, inverting the autocorrelation matrix to obtain an inverse matrix, and multiplying the inverse matrix and the cross-correlation matrix to obtain the adaptive optimal weight values of the main channel and the auxiliary channel.

7. The radar anti-sidelobe jamming method based on electronic reconnaissance according to claim 6, characterized in that, S4 comprises: using the adaptive optimal weight values to perform amplitude weighting and phase weighting on the signals of the main channel and the auxiliary channel, outputting a vector sum signal, completing the interference polarization matching of the auxiliary channel, and thus performing sidelobe cancellation point by point.

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