Electromagnetic radiation in-situ detection system and method based on spatial filtering

Abstract

The invention discloses an electromagnetic radiation in-situ detection system and method based on spatial domain filtering, and relates to the technical field of radio frequency spectrum parameter detection, and the system comprises an array antenna module, a multi-channel radio frequency receiver and an array signal processing module. The array antenna module, the multi-channel radio frequency receiver and the array signal processing module are connected in sequence; the array signal processing module is also connected with the multi-channel radio frequency receiver and the array antenna module; wherein the array antenna module is used for acquiring an initial electromagnetic radiation signal in a preset frequency range; the multi-channel radio frequency receiver is used for processing the initial electromagnetic radiation signal to obtain an intermediate frequency signal with a preset frequency; and the array signal processing module is used for carrying out incoming wave direction estimation and beam forming calculation based on the intermediate frequency signal to obtain a spatial domain filtering spectrogram. According to the invention, the distance between the array elements of the array antenna is adjusted to estimate the incoming wave direction and calculate the beam forming, the incoming wave direction of electromagnetic radiation can be determined, and the electromagnetic radiation signal can be acquired and processed in real time.

Description

Technical Field

[0001] The present application relates to the technical field of radio spectrum parameter detection, and more specifically, to an electromagnetic radiation on-site detection system and method based on spatial domain filtering. Background Art

[0002] In various major events, the self-disturbance and mutual interference problems of radio stations caused by unqualified electromagnetic radiation characteristics of radio equipment are becoming increasingly serious. With the intensive deployment and use of a large number of radio equipment or systems, the electromagnetic environment is becoming more and more complex. In order to avoid mutual influence and interference between radio equipment, it is necessary to quickly and fully grasp the spectrum parameters of radio equipment or systems to analyze the electromagnetic compatibility between radio equipment on different platforms. As an important support means for radio spectrum management and control, radio equipment detection urgently needs to study on-site detection methods to improve the accuracy and effectiveness of on-site measurement of spectrum parameters of radio equipment or systems under emergency conditions, and provide scientific and quantitative opinions and suggestions for the deployment of radio stations.

[0003] In the prior art, for safety reasons, the electromagnetic radiation characteristics of radio equipment are generally tested by shutting down the equipment, or placing the radio equipment in a darkroom or transporting it to an open field for testing. On the one hand, this can prevent the equipment under test from operating in an electromagnetic interference environment, and on the other hand, it can ensure the safety and compliance of the equipment, protect the health and safety of personnel, and facilitate troubleshooting.

[0004] However, large fixed radio stations with important duty tasks are generally not allowed to shut down for closed-field detection of spectrum parameters, and they cannot be placed in a radio darkroom or transported to an open field for detection. They can only be tested on-site in an open field. However, open-field detection has high requirements for the detection site and the external electromagnetic environment. Therefore, effective testing and processing methods are needed. Even if the equipment under test is working under electromagnetic interference, the interference in the external environment can be suppressed or eliminated, so as to achieve fast and accurate measurement of the electromagnetic radiation of the equipment under test on site. Summary of the invention

[0005] In response to at least one defect or improvement need in the prior art, the present invention provides an electromagnetic radiation on-site detection system and method based on spatial domain filtering, which is used to solve the problem that in the prior art, when electromagnetic radiation characteristics detection of large fixed radio stations is carried out by shutting down and closed-field detection, the duty task cannot be completed normally, and when placing them in a radio wave darkroom or transporting them to an open field for detection, high requirements are placed on the detection site and the external electromagnetic environment, resulting in difficulty in implementing detection and low detection efficiency.

[0006] To achieve the above-mentioned object, according to a first aspect of the present invention, there is provided an electromagnetic radiation on-site detection system based on spatial domain filtering, comprising: an array antenna module, a multi-channel radio frequency receiver and an array signal processing module; the array antenna module, the multi-channel radio frequency receiver and the array signal processing module are connected in sequence; the array signal processing module is also connected to the multi-channel radio frequency receiver and the array antenna module;

[0007] Wherein, the array antenna module is used to obtain an initial electromagnetic radiation signal within a preset frequency range;

[0008] The multi-channel radio frequency receiver is used to process the initial electromagnetic radiation signal to obtain an intermediate frequency signal of a preset frequency;

[0009] The array signal processing module is used to estimate the incoming wave direction based on the intermediate frequency signal and perform beamforming calculations to obtain a spatial domain filtered spectrum diagram.

[0010] In a possible implementation, the array antenna module further includes: a plurality of antennas, an antenna adjustment bracket, and an array antenna control module; the plurality of antennas, the antenna adjustment bracket, and the array antenna control module are connected in sequence;

[0011] Among them, several antennas are used to receive initial electromagnetic radiation signals from multiple directions;

[0012] The antenna adjustment bracket is used to adjust the spacing of the antennas under the control of the array antenna control module;

[0013] The array antenna control module is used to generate a spacing adjustment signal to drive the antenna adjustment bracket according to a preset frequency range.

[0014] In a possible implementation, the multi-channel RF receiver further includes: a RF control module, a local oscillator, and a multi-channel RF receiving path; the RF control module, the local oscillator, and the multi-channel RF receiving path are connected in sequence; the RF control module is also connected to the multi-channel RF receiving path;

[0015] Among them, the multi-channel RF receiving path is used to filter, amplify, gain control and frequency convert the initial electromagnetic radiation signal to obtain an intermediate frequency signal;

[0016] The radio frequency control module is used for generating an oscillation control signal and sending it to a local oscillator;

[0017] The local oscillator is used to generate an oscillation signal in response to the oscillation control signal and send it to the multiple radio frequency receiving paths.

[0018] In a possible implementation, the array signal processing module is a FPGA module.

[0019] In a possible implementation, the array antenna control module further includes: a single chip microcomputer, a stepping driver and a servo motor; the single chip microcomputer, the stepping driver and the servo motor are connected in sequence;

[0020] Wherein, the single chip microcomputer is used to generate a spacing adjustment signal according to a preset frequency range;

[0021] The stepper driver is used to drive the servo motor to operate based on the pitch adjustment signal;

[0022] The servo motor is used to drive the antenna adjustment bracket to move to a preset spacing.

[0023] According to a second aspect of the present invention, there is also provided a method for on-site detection of electromagnetic radiation based on spatial domain filtering, based on an on-site detection system of electromagnetic radiation based on spatial domain filtering in any of the possible implementations described above, comprising:

[0024] Adjusting the spacing of the array antennas to obtain an initial electromagnetic radiation signal within a preset frequency range;

[0025] Processing the initial electromagnetic radiation signal to obtain an intermediate frequency signal of a preset frequency;

[0026] The spatial domain filtering spectrum is obtained by estimating the incoming wave direction and calculating the beamforming based on the intermediate frequency signal.

[0027] In a possible implementation, the spatial domain filtering spectrum diagram is obtained by performing an incoming wave direction estimation and a beamforming calculation based on the intermediate frequency signal, and further includes:

[0028] Digitally sampling the intermediate frequency signal to obtain a digital intermediate frequency signal;

[0029] Performing quadrature demodulation on the digitized intermediate frequency signal to obtain a baseband signal;

[0030] The multiple signal classification algorithm is used to estimate the direction of arrival of the baseband signal;

[0031] The minimum variance distortion-free response algorithm is used to perform beamforming calculations on the baseband signal to obtain the spatial domain filtered spectrum.

[0032] In a possible implementation, a multiple signal classification algorithm is used to estimate the direction of arrival of a baseband signal, including:

[0033] Recombining the baseband signal to obtain an electromagnetic signal matrix of a preset format;

[0034] The deviation effect of the electromagnetic signal matrix estimation variance is trained and modeled to obtain a first symmetric matrix;

[0035] Perform similarity transformation on the first symmetric matrix and calculate the eigenvalues ​​of the transformed matrix;

[0036] The signal arrival azimuth is set, and traversal is performed based on the matrix eigenvalue and the signal arrival azimuth to obtain the spatial incoming wave direction diagram.

[0037] In a possible implementation, a minimum variance distortion-free response algorithm is used to perform beamforming calculation on a baseband signal to obtain a spatial domain filtering spectrum diagram, including:

[0038] Determine the interference suppression direction from the incoming wave direction diagram in the air domain, and obtain the steering vector according to the interference suppression direction;

[0039] Performing a covariance matrix solving operation on the steering vector to obtain a second symmetric matrix;

[0040] Inverse the diagonal loading matrix of the second symmetric matrix and modify the eigenvalues;

[0041] Perform matrix multiplication and division operations based on the covariance matrix and the array steering vector to obtain a weight vector;

[0042] The spatial domain filtering spectrum is obtained by weighting and Fourier transforming the weight vector and the intermediate frequency signal.

[0043] In a possible implementation, adjusting the spacing of the array antennas to obtain an initial electromagnetic radiation signal within a preset frequency range includes:

[0044] Initialize the spacing between antennas in the array antenna module;

[0045] Calculating the power of half wavelength according to the preset frequency range;

[0046] When the power of half wavelength is within the preset reconstruction range, the spacing between antennas is adjusted according to the power of half wavelength; otherwise, it is adjusted according to integer multiples of half wavelength to obtain the initial electromagnetic radiation signal in the preset frequency range.

[0047] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0048] The electromagnetic radiation on-site detection system based on spatial domain filtering provided by the present invention obtains the initial electromagnetic radiation signal of the preset frequency range through the array antenna module, which is helpful to collect the target signal in a targeted manner and reduce the interference of the external environment, thereby improving the accuracy of electromagnetic radiation on-site detection; the multi-channel radio frequency receiver processes the initial signal to obtain the intermediate frequency signal of the preset frequency, which can further purify the target signal and provide a high-quality data basis for the subsequent electromagnetic radiation signal processing; the array signal processing module uses the processed intermediate frequency signal to estimate the incoming wave direction and beam forming calculation, and through the spatial domain filtering technology, the incoming wave direction of the electromagnetic radiation can be accurately determined to improve the accuracy and efficiency of detection. The present invention can adapt to electromagnetic radiation detection tasks with different frequency ranges and detection requirements by adjusting the parameters of the array antenna module, such as the array scale, the array element spacing, etc., so that the electromagnetic radiation signal can be acquired and processed in real time, and finally the array signal processing module is used to perform rapid calculation and analysis to realize virtual darkroom detection of the electromagnetic radiation of the radio equipment to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 A schematic structural diagram of an embodiment of an electromagnetic radiation on-site detection system based on spatial domain filtering provided by the present invention;

[0051] Figure 2 A schematic structural diagram of an embodiment of an array antenna module provided by the present invention;

[0052] Figure 3 A schematic diagram of a flow chart of an embodiment of a method for on-site detection of electromagnetic radiation based on spatial domain filtering provided by the present invention;

[0053] Figure 4 The present invention provides Figure 3 A schematic diagram of a flow chart of an embodiment of step S303;

[0054] Figure 5 The present invention provides Figure 4 A schematic flow chart of an embodiment of step S403;

[0055] Figure 6 The present invention provides Figure 4 A flowchart of an embodiment of step S404;

[0056] Figure 7The present invention provides Figure 3 Schematic diagram of a flow chart of an embodiment of step S301 in FIG. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] The terms "first", "second", "third", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0059] The present invention provides an electromagnetic radiation on-site detection system and method based on spatial domain filtering, which are respectively described below.

[0060] See also Figure 1 , Figure 1 A schematic diagram of the structure of an embodiment of an electromagnetic radiation on-site detection system based on spatial domain filtering provided by the present invention. In a specific embodiment of the present invention, a system 100 for electromagnetic radiation on-site detection based on spatial domain filtering is disclosed, comprising: an array antenna module 110, a multi-channel radio frequency receiver 120, and an array signal processing module 130; the array antenna module 110, the multi-channel radio frequency receiver 120, and the array signal processing module 130 are connected in sequence; the array signal processing module 130 is also connected to the multi-channel radio frequency receiver 120 and the array antenna module 110;

[0061] The array antenna module 110 is used to obtain an initial electromagnetic radiation signal within a preset frequency range;

[0062] The multi-channel radio frequency receiver 120 is used to process the initial electromagnetic radiation signal to obtain an intermediate frequency signal of a preset frequency;

[0063] The array signal processing module 130 is used to perform incoming wave direction estimation and beamforming calculation based on the intermediate frequency signal to obtain a spatial domain filtering spectrum diagram.

[0064] In the above embodiment, the array antenna module 110, the multi-channel RF receiver 120 and the array signal processing module 130 are connected in sequence to form a complete signal acquisition, conversion and processing link. In order to enhance the flexibility and interactivity of the system, the array signal processing module 130 also establishes feedback and control connections with the multi-channel RF receiver 120 and the array antenna module 110, respectively, to ensure that the entire system can respond in real time and optimize the processing flow.

[0065] During the operation of the system, the array antenna module 110 is responsible for capturing and obtaining initial electromagnetic radiation signals within a preset frequency range from the radio device under test and the surrounding environment. The initial electromagnetic radiation signals may come from various electromagnetic radiation sources, such as communication equipment, radar systems or industrial equipment.

[0066] The multi-channel RF receiver 120 further processes the initial electromagnetic radiation signal received from the array antenna module 110, and uses RF technology to convert the original signal into an intermediate frequency signal of a preset frequency, which is convenient for the array signal processing module to collect, process and calculate.

[0067] The array signal processing module 130 performs the estimation of the incoming wave direction and the beamforming calculation based on the intermediate frequency signal received from the multi-channel RF receiver 120 to obtain a spatial domain filtering spectrum diagram. The incoming wave direction of the electromagnetic radiation signal can be accurately determined by calculation, and the target signal can be enhanced and the interference signal can be suppressed by the beamforming technology. Finally, the array signal processing module 130 will generate a spatial domain filtering spectrum diagram, which intuitively shows the spectrum distribution after the interference signal is "zeroed".

[0068] Compared with the prior art, the electromagnetic radiation on-site detection system 100 based on spatial domain filtering provided in this embodiment obtains the initial electromagnetic radiation signal of the preset frequency range through the array antenna module 110, which is helpful to collect the target signal in a targeted manner and reduce the interference of the external environment, thereby improving the accuracy of electromagnetic radiation on-site detection; the multi-channel radio frequency receiver 120 processes the initial signal to obtain the intermediate frequency signal of the preset frequency, which can further purify the target signal, and provide a high-quality data basis for the subsequent electromagnetic radiation signal processing; the array signal processing module 130 uses the processed intermediate frequency signal to estimate the incoming wave direction and beam forming calculation, and through the spatial domain filtering technology, the incoming wave direction of the electromagnetic radiation can be accurately determined, thereby improving the accuracy and efficiency of detection. The present invention can adapt to electromagnetic radiation detection tasks with different frequency ranges and detection requirements by adjusting the parameters of the array antenna module 110, such as the array scale, the array element spacing, etc., so that the electromagnetic radiation signal can be acquired and processed in real time, and finally the array signal processing module 130 performs rapid calculation and analysis to realize virtual darkroom detection of electromagnetic radiation of the radio equipment to be tested.

[0069] In some embodiments of the present invention, the array antenna module 110 further includes: a plurality of antennas, an antenna adjustment bracket, and an array antenna control module; the plurality of antennas, the antenna adjustment bracket, and the array antenna control module are connected in sequence;

[0070] Among them, several antennas are used to receive initial electromagnetic radiation signals from multiple directions;

[0071] The antenna adjustment bracket is used to adjust the spacing of the antennas under the control of the array antenna control module;

[0072] The array antenna control module is used to generate a spacing adjustment signal to drive the antenna adjustment bracket according to a preset frequency range.

[0073] In the above embodiment, several antennas can cover a wide range of airspace, so as to receive initial electromagnetic radiation signals from multiple directions or azimuths. It is understandable that all antennas are mounted on the antenna adjustment bracket, and the spacing between them can be adjusted along with the antenna adjustment bracket.

[0074] The antenna adjustment bracket is the bridge between the antenna and the control system. Under the control of the array antenna control module, the antenna adjustment bracket can dynamically adjust the spacing between each antenna unit. This is crucial for optimizing the performance of the antenna array because it can flexibly adjust the geometric layout of the array according to different application scenarios and signal characteristics, thereby achieving the best spatial spectrum estimation.

[0075] The array antenna control module, through its built-in algorithms and logic, can automatically generate spacing adjustment signals according to the preset frequency range, and accurately drive the antenna adjustment bracket to perform corresponding adjustment actions.

[0076] See also Figure 2 , Figure 2 A schematic diagram of the structure of an embodiment of the array antenna module provided by the present invention. In a specific embodiment of the present invention, the array antenna module 110 includes 7 whip antennas, an antenna adjustment bracket, and an array antenna control module. The working range of each whip antenna covers 300MHz to 3000MHz. The antenna body adopts an asymmetric double-cone structure and inductive loading technology to effectively reduce the antenna size and expand the antenna working bandwidth. The 7-channel array antenna is evenly placed on a uniform circular array (antenna adjustment bracket) composed of precision electrically controlled slide rails. The array antenna module 110 can adjust the array element spacing of the array antenna with high precision through a servo motor, and adapt the system to meet the array element spacing of a power multiple or integer multiple of half-wavelength λ / 2 (λ, working wavelength) at different operating frequencies, so as to optimize the frequency range covering a 10-fold tuning ratio.

[0077] In some embodiments of the present invention, the multi-channel RF receiver 120 further includes: a RF control module, a local oscillator, and a multi-channel RF receiving path; the RF control module, the local oscillator, and the multi-channel RF receiving path are connected in sequence; the RF control module is also connected to the multi-channel RF receiving path;

[0078] Among them, the multi-channel RF receiving path is used to filter, amplify, gain control and frequency convert the initial electromagnetic radiation signal to obtain an intermediate frequency signal;

[0079] The radio frequency control module is used for generating an oscillation control signal and sending it to a local oscillator;

[0080] The local oscillator is used to generate an oscillation signal in response to the oscillation control signal and send it to the multiple radio frequency receiving paths.

[0081] In the above embodiment, multiple RF receiving paths work independently and in parallel to receive the initial electromagnetic radiation signal from the external environment, which can remove the noise and interference of the initial electromagnetic radiation signal and retain useful information. Subsequently, the filtered signal is sent to the amplifier for enhancement to ensure that its strength is sufficient for subsequent processing. The gain control mechanism allows the amplification factor to be adjusted according to the actual situation of the signal to avoid distortion caused by excessive signal strength or loss caused by excessive signal weakness. Finally, the signal is frequency-converted to convert the high-frequency RF signal into an intermediate frequency signal for subsequent digital signal processing and analysis.

[0082] The RF control module can generate an oscillation control signal according to preset parameters and conditions, and then send the oscillation control signal to the local oscillator to guide it to generate an oscillation signal of a specific frequency. The RF control module also monitors and adjusts the frequency and phase of the oscillation signal in real time to ensure that it is synchronized and consistent with the signals in the multi-channel RF receiving path.

[0083] The local oscillator accurately generates the oscillation signal of the required frequency according to the oscillation control signal sent by the RF control module, and sends these signals to the multi-channel RF receiving path. The oscillation signal is mixed with the RF signal during the frequency conversion process to generate an intermediate frequency signal, which is convenient for the array signal processing module to collect, process and calculate.

[0084] In a specific embodiment of the present invention, adapted to the array antenna module 110, seven RF receiving paths are used. One RF receiving path may include an input protection attenuator, a filter, a low noise amplifier and an attenuator to form an automatic gain control (AGC) amplifier, a mixer, etc. It can be understood that the filtering, amplification, gain control and frequency conversion processing of the path can be achieved by existing technologies, and the present invention does not impose further restrictions on this.

[0085] In some embodiments of the present invention, the array signal processing module 130 is a FPGA module.

[0086] In the above embodiment, the array signal processing module 130 mainly completes the digital sampling, digital down-conversion, extraction filtering, and signal processing such as arrival direction estimation, beam forming, and spectrum analysis of 7-channel RF signals. The system integrates intermediate frequency broadband direct sampling and multi-channel parallel signal processing technology to achieve minimum variance and distortion-free spatial spectrum estimation, and obtains spectrum information by performing fast Fourier transform (FFT) on the IQ data processed by spatial domain filtering.

[0087] In some embodiments of the present invention, the array antenna control module further includes: a single chip microcomputer, a stepping driver and a servo motor; the single chip microcomputer, the stepping driver and the servo motor are connected in sequence;

[0088] Wherein, the single chip microcomputer is used to generate a spacing adjustment signal according to a preset frequency range;

[0089] The stepper driver is used to drive the servo motor to operate based on the pitch adjustment signal;

[0090] The servo motor is used to drive the antenna adjustment bracket to move to a preset spacing.

[0091] In the above embodiment, the single chip microcomputer can generate a spacing adjustment signal according to a preset frequency range. The spacing adjustment signal is the key to controlling the antenna spacing adjustment and can accurately reflect the system's expectations for the geometric layout of the antenna array.

[0092] The stepper driver receives the spacing adjustment signal from the microcontroller and converts it into a step pulse signal, thereby driving the servo motor to run at a precise pace. The stepper driver has the characteristics of high precision, low noise and good stability. It can ensure that the servo motor always maintains smooth and precise movement during operation, thereby achieving precise control of the antenna adjustment bracket.

[0093] The servo motor accurately drives the antenna adjustment bracket to the preset spacing position according to the step pulse signal sent by the stepper driver. The servo motor has the characteristics of high torque, high precision and fast response. It can complete complex motion control tasks in a very short time to ensure that the geometric layout of the antenna array is always kept in the optimal state. At the same time, the servo motor also has safety functions such as overload protection and overheating protection. It can shut down in time when encountering abnormal conditions to protect the safe operation of the entire system.

[0094] See also Figure 3 , Figure 3The present invention is a flowchart of an embodiment of an electromagnetic radiation on-site detection method based on spatial domain filtering provided by the present invention. According to a second aspect of the present invention, a method for electromagnetic radiation on-site detection based on spatial domain filtering is also provided. The electromagnetic radiation on-site detection system 100 based on spatial domain filtering in any of the above embodiments includes:

[0095] S301, adjusting the spacing of the array antenna to obtain an initial electromagnetic radiation signal within a preset frequency range;

[0096] S302, processing the initial electromagnetic radiation signal to obtain an intermediate frequency signal of a preset frequency;

[0097] S303: Estimating the incoming wave direction and performing beamforming calculation based on the intermediate frequency signal to obtain a spatial domain filtering spectrum diagram.

[0098] In the above embodiment, first, the physical spacing between the antennas in the array antenna is optimized according to the specific frequency range of the electromagnetic radiation to be detected. The physical spacing between the antennas directly affects the system's reception efficiency and resolution of electromagnetic waves within a specific frequency range. Through precise configuration, the system can efficiently capture the initial electromagnetic radiation signal in the environment and provide high-quality data input for subsequent processing. As a preferred embodiment, the preset frequency range in the present invention is 300MHz-3000MHz.

[0099] After obtaining the initial signal, the initial signal is preprocessed, which may involve a series of operations such as signal amplification, filtering, and down-conversion, aiming to convert the broadband original signal into an intermediate frequency signal with a specific center frequency and bandwidth. This not only helps to reduce interference from the external environment, but also makes the signal more suitable for subsequent spectrum analysis and direction estimation, thereby improving the sensitivity and accuracy of the entire detection system.

[0100] Using advanced digital signal processing algorithms, such as the Multiple Signal Classification (MUSIC) algorithm, the incoming wave direction of the intermediate frequency signal is estimated to determine the specific direction of the electromagnetic wave reaching the array antenna. Subsequently, the minimum variance distortion-free response algorithm is used to dynamically adjust the weighting coefficients of the array antenna according to the estimated direction information, so that the system can form a "null sink" in a specific direction, thereby suppressing the interference signal in that direction. Finally, combined with the above processing results, the system generates a spatial domain filtering spectrum diagram, which intuitively shows the spectrum distribution after the interference signal is "nulled", realizing virtual darkroom detection of the electromagnetic radiation of the radio equipment under test.

[0101] See also Figure 4 , Figure 4 The present invention provides Figure 3The flowchart of an embodiment of step S303 in the embodiment of the present invention is as follows. In some embodiments of the present invention, the spatial domain filtering spectrum diagram is obtained by performing the incoming wave direction estimation and beamforming calculation based on the intermediate frequency signal, and further includes:

[0102] S401, digitally sampling the intermediate frequency signal to obtain a digital intermediate frequency signal;

[0103] S402, performing orthogonal demodulation on the digitized intermediate frequency signal to obtain a baseband signal;

[0104] S403, using a multiple signal classification algorithm to estimate the direction of arrival of the baseband signal;

[0105] S404: Perform beamforming calculation on the baseband signal using a minimum variance distortion-free response algorithm to obtain a spatial domain filtering spectrum diagram.

[0106] In the above embodiment, after obtaining the intermediate frequency signal, digital sampling is first required to convert the continuous intermediate frequency signal into a discrete digitized intermediate frequency signal for subsequent processing by a computer or a digital signal processing system. The sampling process needs to ensure that the sampling frequency is high enough to comply with the Nyquist sampling theorem to avoid signal distortion. The digitized intermediate frequency signal obtained after sampling will serve as the basis for subsequent processing.

[0107] After obtaining the digitized intermediate frequency signal, the next step is orthogonal demodulation, which is a technique for converting a modulated signal (such as an intermediate frequency signal) back to the original baseband signal. Through orthogonal demodulation, the carrier component of the signal can be removed to obtain a baseband signal containing the original information (such as amplitude, phase, etc.). Orthogonal demodulation usually involves the extraction of two orthogonal components (such as I and Q components), which will be used for subsequent signal processing.

[0108] After obtaining the baseband signal, the multiple signal classification (MUSIC) algorithm is used to estimate the direction of the wave. The MUSIC algorithm is a high-resolution angle estimation algorithm that estimates the signal's arrival angle by analyzing the orthogonality between the signal subspace and the noise subspace. In electromagnetic radiation detection, the MUSIC algorithm can accurately estimate the direction of the electromagnetic wave arriving at the array antenna, providing key information for subsequent beamforming.

[0109] Finally, the minimum variance distortionless response (MVDR) algorithm is used for beamforming calculation. The MVDR algorithm is an adaptive beamforming algorithm that can minimize the impact of interference and noise while keeping the desired signal undistorted. Through the MVDR algorithm, the weighting coefficients of the array antenna can be dynamically adjusted according to the results of the estimated direction of the incoming wave, thereby forming a "null sink" in a specific direction. Finally, combined with the results of beamforming, a spatial domain filtered spectrum diagram can be obtained, which shows the spectrum distribution after the interference signal is "nulled".

[0110] See also Figure 5 , Figure 5 The present invention provides Figure 4 In some embodiments of the present invention, the baseband signal is estimated in terms of the direction of arrival by using a multiple signal classification algorithm, including:

[0111] S501, reorganizing the baseband signal to obtain an electromagnetic signal matrix in a preset format;

[0112] S502, training and modeling the deviation effect of the electromagnetic signal matrix estimation variance to obtain a first symmetric matrix;

[0113] S503, performing a similarity transformation on the first symmetric matrix, and calculating the eigenvalues ​​of the transformed matrix;

[0114] S504: Set the signal arrival azimuth, and perform traversal based on the matrix eigenvalues ​​and the signal arrival azimuth to obtain a spatial incoming wave pattern.

[0115] In the above embodiment, after the baseband signals are obtained, the signals need to be reorganized to form an electromagnetic signal matrix of a preset format, and the signals from different antenna units are arranged in time or frequency order to construct a two-dimensional matrix containing the signals received by all antenna units. Each row of the matrix represents a signal received by an antenna unit, and each column represents the signals received by different antenna units at the same time or frequency point. By reorganizing the signals, the MUSIC algorithm can be used more conveniently for subsequent processing.

[0116] The purpose of training and modeling the variance deviation effect of the electromagnetic signal matrix is ​​to estimate the statistical characteristics of the signal and noise by calculating the covariance matrix (or correlation matrix) of the signal matrix. The covariance matrix is ​​a symmetric matrix that reflects the correlation between different elements in the signal matrix. Through the training process, a first symmetric matrix containing the statistical characteristics of the signal and noise can be obtained. The first symmetric matrix will be used for subsequent eigenvalue decomposition and wave direction estimation.

[0117] After obtaining the first symmetric matrix, it is necessary to perform a similarity transformation (such as eigenvalue decomposition or singular value decomposition) on it. The purpose of the similarity transformation is to decompose the matrix into a series of eigenvalues ​​and corresponding eigenvectors, which reflect the energy distribution of the matrix in different directions, while the eigenvectors correspond to the signal components in these directions. By calculating the eigenvalues ​​of the transformed matrix, more detailed information about the statistical characteristics of the signal and noise can be obtained.

[0118] Finally, the signal arrival azimuth is set, and traversal is performed based on the matrix eigenvalues ​​and the signal arrival azimuth. The traversal process involves setting the signal arrival azimuth one by one within a predetermined angle range (such as 0° to 360°), and calculating the corresponding MUSIC spectrum value at each angle. The MUSIC spectrum value is calculated by the orthogonality between the noise subspace obtained by eigenvalue decomposition and the steering vector (the vector representing the direction of signal arrival). When the steering vector is consistent with the direction of signal arrival, the MUSIC spectrum value will reach the maximum. By traversing all possible angles and drawing a curve of the MUSIC spectrum value changing with the angle (i.e., the spatial wave direction diagram), the actual arrival direction of the signal can be determined.

[0119] Specifically, the arrival angle estimation algorithm finds the direction based on the phase difference caused by the different arrival times of signals from different directions. The spatial resolution of traditional algorithms (such as spatial FFT) is limited by the number of antennas and cannot meet the requirements of practical applications. Therefore, super-resolution algorithms are generally used in engineering to estimate the signal arrival angle. The MUSIC algorithm is used in this design, and its deduction process is as follows:

[0120] The K far-field narrowband signals are transmitted from θ1,θ2,...,θ k When the direction is incident on an array of M elements, the received signal is:

[0121] x(n)=As(n)+v(n);

[0122] Where x(n) is the array received data vector, A is the direction matrix, s(n) is the space vector signal, and v(n) is the noise vector. Expanding the above formula yields:

[0123]

[0124] If the signal sources are statistically independent of each other, that is:

[0125]

[0126] Among them, P k represents the average power of the Kth signal, and the signal correlation matrix P is a diagonal matrix, that is:

[0127] P=E[s(n)s k (n)]=diag[P1,P2,...,P k ];

[0128] Define the spatial correlation matrix of the received signal vector as R, then:

[0129] R = E[x(n)x H (n)]=APA H +σ 2 I;

[0130] Among them, σ 2 is the variance of Gaussian white noise. To ensure that the columns of the directional matrix A are linearly independent, M> should be met, that is, the number of array elements is greater than the number of signal sources. Because the directional matrix A is a Vandermonde matrix and P is a positive definite matrix, then APA H The rank satisfies rank(APA H )=K, so the matrix APA h There are K positive eigenvalues.

[0131] Perform eigenvalue decomposition on the correlation matrix R and arrange these eigenvalues ​​in a monotonically non-increasing order, namely:

[0132] λ1≥λ2≥...≥λ K ≥λ K+1 =λ K+2 =... =λ M =σ 2 ;

[0133] The normalized eigenvectors corresponding to these eigenvalues ​​are u1,...,u k ,u k+1 ,...,u M , where u1,...,u k and u k+1 ,...,u M They are respectively the signal subspace E s and the noise subspace E N ,Right now:

[0134] E s =span[u1,u2,...,u K ];

[0135] E N =span[u K+1 ,u K+2 ,...,u M ];

[0136] Define the matrix G = [u L+1 ,u K+2 ,…,u M ], because the matrix A is a column full rank matrix, P is a full rank matrix, it can be proved that G H A=G H [a(θ1)a(θ2)...a(θ N )[=0, where a(θ) is the array steering vector.

[0137] In practical applications, based on the received data x(n) obtained by N snapshots, n = 1, 2, ..., N, the spatial correlation matrix R is estimated by time averaging, which is:

[0138]

[0139] The MUSIC spectrum can be estimated as:

[0140]

[0141] Among them, the matrix It is through the matrix The K peak positions of the MUSIC spectrum are the wave arrival directions θ k , where k = 1, 2, ..., K. Since the spectrum obtained by the MUSIC algorithm is not the spatial power spectrum of the signal, the MUSIC spectrum is usually called a pseudo-spectrum.

[0142] From the above derivation, it can be seen that using the MUSIC method for spectrum peak search can provide a spatial resolution far exceeding that of traditional algorithms, providing more accurate prior information for spatial domain filtering.

[0143] See also Figure 6 , Figure 6 The present invention provides Figure 4 In some embodiments of the present invention, the minimum variance distortionless response algorithm is used to perform beamforming calculation on the baseband signal to obtain a spatial domain filtering spectrum diagram, including:

[0144] S601, determining an interference suppression direction from a spatial incoming wave pattern, and obtaining a steering vector according to the interference suppression direction;

[0145] S602, performing a covariance matrix solving operation on the steering vector to obtain a second symmetric matrix;

[0146] S603, inverting the diagonal loading matrix of the second symmetric matrix array, and correcting the eigenvalues;

[0147] S604, performing matrix multiplication and division operations based on the covariance matrix and the array steering vector to obtain a weight vector;

[0148] S605 , weighting and Fourier transform are performed according to the weight vector and the intermediate frequency signal to obtain a spatial domain filtering spectrum diagram.

[0149] In the above embodiment, after obtaining the spatial wave pattern, it is first necessary to determine the source direction of the interference signal based on the information in the pattern, that is, the interference suppression direction. By identifying and analyzing the peaks in the spatial wave pattern, it is possible to determine which directions of the signals are desired signals and which directions of the signals are interference signals. Once the interference suppression direction is determined, the corresponding steering vector can be calculated based on the configuration of the array antenna and the signal propagation characteristics. The steering vector represents the phase and amplitude relationship when the signal arrives at the array antenna from a specific direction.

[0150] After obtaining the steering vector, the covariance matrix solution operation is performed to estimate the covariance matrix of the signal based on the received baseband signal and the known steering vector. The covariance matrix is ​​a symmetric matrix that reflects the correlation between the elements in the signal. In the MVDR algorithm, the solution of the covariance matrix usually involves steps such as sampling the received signal and calculating the sample covariance matrix. The final second symmetric matrix will be used for subsequent beamforming calculations.

[0151] After obtaining the second symmetric matrix, in order to perform beamforming calculations, it is necessary to perform diagonal loading matrix inversion. Diagonal loading is a regularization technique that avoids numerical instability problems when inverting the matrix by adding a small positive number to the diagonal of the matrix. After diagonal loading, the matrix is ​​inverted again to obtain the inverse matrix. In addition, in order to optimize the performance of beamforming, it may be necessary to correct the eigenvalues ​​of the inverse matrix to ensure that the signal distortion after beamforming is minimized.

[0152] After obtaining the inverse matrix and the corrected eigenvalues, we need to perform matrix multiplication and division operations based on the covariance matrix and the array steering vector to calculate the weight vector. The weight vector is a complex vector that represents the weight coefficient of each unit in the array antenna for the received signal. The weight coefficient determines the direction and shape of the beamforming. By optimizing the weight vector, the array antenna can form a "null" in the desired direction to suppress the interference signal in that direction.

[0153] Finally, a weighted operation is performed based on the calculated weight vector and the intermediate frequency signal, and then the weighted signal is Fourier transformed to obtain a spatial domain filtering spectrum diagram. The weighted operation is to multiply the intermediate frequency signal by the weight vector to adjust the amplitude and phase of the signal received by each antenna unit; the Fourier transform is to convert the weighted signal from the time domain to the frequency domain to show the distribution of the signal at different frequencies. Through the spatial domain filtering spectrum diagram, you can intuitively see the spectrum distribution after the interference signal is "zeroed", and realize virtual darkroom detection of the electromagnetic radiation of the radio equipment to be tested.

[0154] Specifically, the output power of the array is (assuming that the signal is completely unrelated to the interference plus noise):

[0155] E[YY H ]=W H E[SS H ]W+W H E[NN H ]W=W H R ss W+W H R NN W(1);

[0156] Where R ss ,R NN are the covariance matrices of the signal and interference plus noise respectively. The signal-to-noise ratio of the array output is:

[0157]

[0158] R NN Decomposed into:

[0159] R NN =L H L(3);

[0160] Where L is a reversible square matrix. Substituting (3) into (2) we get:

[0161]

[0162] Substituting (4) into (4) we get:

[0163]

[0164] According to Schwartz inequality:

[0165] (PW) H P -H a s a s H P -1 (PW)≤[(PW) H (PW)]×[(a s H P -1 )(P -H a s )](7);

[0166]

[0167] If and only if:

[0168] QP -H a s =PW(9);

[0169] The equality holds. The optimal weight vector can be obtained:

[0170] W opt =QP -1 P -H a s =QR NN -1 a s (10);

[0171] By the linear constraint W opt H a s =1 So the MVDR optimal weight vector can be expressed as:

[0172]

[0173] Where a s is the desired direction vector, R NN is the interference plus noise covariance matrix.

[0174] From the expression of the MVDR weight vector, we can see that the weight vector can change according to the change of the covariance matrix of noise plus interference. Therefore, the MVDR algorithm can adaptively maximize the SINR of the array output in the desired direction to achieve the best effect.

[0175] See also Figure 7 , Figure 7 The present invention provides Figure 3 In some embodiments of the present invention, adjusting the spacing of the array antenna to obtain an initial electromagnetic radiation signal within a preset frequency range includes:

[0176] S701, initializing the distance between antennas in the array antenna module;

[0177] S702, calculating the power of half wavelength according to a preset frequency range;

[0178] S703. When the power of half wavelength is within a preset reconstruction range, the spacing between antennas is adjusted according to the power of half wavelength; otherwise, the spacing is adjusted according to an integer multiple of half wavelength to obtain an initial electromagnetic radiation signal within a preset frequency range.

[0179] In the above embodiment, before starting to adjust the array antenna spacing, it is first necessary to initialize the antenna spacing in the array antenna module 110 to determine the basic layout of the antenna array and the initial array element spacing of the uniform linear array or uniform circular array. The selection of the initial array element spacing can be preset according to a specific application scenario, and the present invention does not impose further restrictions on this. Through the initialization setting, a reference point can be provided for subsequent spacing adjustment.

[0180] In electromagnetic wave theory, there is an inverse relationship between wavelength and frequency, that is, the longer the wavelength, the lower the frequency; the shorter the wavelength, the higher the frequency. Therefore, in order to obtain electromagnetic radiation signals within a specific frequency range, it is necessary to calculate the wavelength corresponding to the frequency range. In practical applications, it is necessary to calculate the wavelength based on the power of half a wavelength (such as a quarter wavelength, an eighth wavelength, etc.) or an integer multiple of half a wavelength in order to better match the characteristics and application requirements of the antenna array and ensure the best spatial spectrum estimation effect within the preset frequency range. By calculating the power of half a square wavelength, a theoretical basis can be provided for subsequent spacing adjustments.

[0181] After obtaining the power of the half-square wavelength, it is necessary to determine whether it is within the preset reconstruction range. The reconstruction range refers to the wavelength range in which the antenna array can work stably and meet specific performance requirements. If the power of the half-square wavelength is within the reconstruction range, the spacing between antennas can be adjusted according to the wavelength. The purpose of adjusting the spacing is to match the performance parameters of the antenna array, such as beam pointing, beam width, and gain, with the preset frequency range. By adjusting the spacing, the accuracy and resolution of the antenna array spatial spectrum estimation can be optimized.

[0182] In summary, the electromagnetic radiation on-site detection system 100 based on spatial filtering provided by the present invention obtains the initial electromagnetic radiation signal of the preset frequency range through the array antenna module 110, which is helpful to collect the target signal in a targeted manner and reduce the interference of the external environment, thereby improving the accuracy of electromagnetic radiation on-site detection; the multi-channel radio frequency receiver 120 processes the initial signal to obtain the intermediate frequency signal of the preset frequency, which can further purify the target signal, and provide a high-quality data basis for the subsequent electromagnetic radiation signal processing; the array signal processing module 130 uses the processed intermediate frequency signal to estimate the incoming wave direction and beamforming calculation, and through the spatial filtering technology, the source direction of the electromagnetic radiation can be accurately determined to improve the accuracy and efficiency of the detection. The present invention can adapt to electromagnetic radiation detection tasks with different frequency ranges and detection requirements by adjusting the parameters of the array antenna module 110, such as the array scale, the array element spacing, etc., so that the electromagnetic radiation signal can be acquired and processed in real time, and finally the array signal processing module 130 is used to quickly calculate and analyze, and the electromagnetic radiation of the radio equipment to be tested is realized in a virtual darkroom detection.

[0183] The present application also provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are implemented. The computer-readable storage medium may include, but is not limited to, any type of disk, including a floppy disk, an optical disk, a DVD, a CD-ROM, a micro drive, and a magneto-optical disk, a ROM, a RAM, an EPROM, an EEPROM, a DRAM, a VRAM, a flash memory device, a magnetic card or an optical card, a nanosystem (including a molecular memory IC), or any type of medium or device suitable for storing instructions and / or data.

[0184] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0185] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0186] In the several embodiments provided in the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0187] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0188] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0189] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0190] A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, which can include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0191] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0192] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0193] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electromagnetic radiation on-site detection system based on spatial domain filtering, characterized in that: include: Array antenna module, multi-channel radio frequency receiver and array signal processing module; The array antenna module, the multi-channel radio frequency receiver and the array signal processing module are connected in sequence; the array signal processing module is also connected to the multi-channel radio frequency receiver and the array antenna module; Wherein, the array antenna module is used to obtain an initial electromagnetic radiation signal within a preset frequency range; The multi-channel radio frequency receiver is used to process the initial electromagnetic radiation signal to obtain an intermediate frequency signal of a preset frequency; The array signal processing module is used to perform incoming wave direction estimation and beamforming calculation based on the intermediate frequency signal to obtain a spatial domain filtering spectrum diagram.

2. The electromagnetic radiation on-site detection system based on spatial domain filtering according to claim 1, characterized in that: The array antenna module further comprises: a plurality of antennas, an antenna adjustment bracket and an array antenna control module; the plurality of antennas, the antenna adjustment bracket and the array antenna control module are connected in sequence; Wherein, the plurality of antennas are used to receive the initial electromagnetic radiation signals in multiple directions; The antenna adjustment bracket is used to adjust the spacing of the antennas under the control of the array antenna control module; The array antenna control module is used to generate a spacing adjustment signal according to the preset frequency range to drive the antenna adjustment bracket.

3. The electromagnetic radiation on-site detection system based on spatial domain filtering according to claim 1, characterized in that: The multi-channel RF receiver further includes: a RF control module, a local oscillator and a multi-channel RF receiving path; the RF control module, the local oscillator and the multi-channel RF receiving path are connected in sequence; the RF control module is also connected to the multi-channel RF receiving path; Wherein, the multi-channel radio frequency receiving path is used to filter, amplify, gain control and frequency convert the initial electromagnetic radiation signal to obtain the intermediate frequency signal; The radio frequency control module is used to generate an oscillation control signal and send it to the local oscillator; The local oscillator is used to generate an oscillation signal in response to the oscillation control signal and send it to the multi-channel radio frequency receiving path.

4. The electromagnetic radiation on-site detection system based on spatial domain filtering according to claim 1, characterized in that: The array signal processing module is a FPGA module.

5. The electromagnetic radiation on-site detection system based on spatial domain filtering as claimed in claim 2, characterized in that: The array antenna control module further includes: a single chip microcomputer, a stepping driver and a servo motor; the single chip microcomputer, the stepping driver and the servo motor are connected in sequence; Wherein, the single chip microcomputer is used to generate a spacing adjustment signal according to the preset frequency range; The stepper driver is used to drive the servo motor to operate based on the spacing adjustment signal; The servo motor is used to drive the antenna adjustment bracket to move to a preset distance.

6. A method for on-site detection of electromagnetic radiation based on spatial domain filtering, based on the on-site detection system of electromagnetic radiation based on spatial domain filtering as described in any one of claims 1 to 5, characterized in that: include: Adjusting the spacing of the array antennas to obtain an initial electromagnetic radiation signal within a preset frequency range; Processing the initial electromagnetic radiation signal to obtain an intermediate frequency signal of a preset frequency; The spatial domain filtering spectrum diagram is obtained by performing incoming wave direction estimation and beamforming calculation based on the intermediate frequency signal.

7. The electromagnetic radiation on-site detection method based on spatial domain filtering according to claim 6, characterized in that: The method of performing the estimation of the incoming wave direction and the beamforming calculation based on the intermediate frequency signal to obtain the spatial domain filtering spectrum diagram also includes: Digitally sampling the intermediate frequency signal to obtain a digitized intermediate frequency signal; Performing orthogonal demodulation on the digitized intermediate frequency signal to obtain a baseband signal; Using a multiple signal classification algorithm to estimate the direction of arrival of the baseband signal; The baseband signal is beamformed using a minimum variance distortion-free response algorithm to obtain a spatial domain filtering spectrum diagram.

8. The electromagnetic radiation on-site detection method based on spatial domain filtering according to claim 7, characterized in that: The method of estimating the direction of arrival of the baseband signal by using a multiple signal classification algorithm comprises: Recombining the baseband signal to obtain an electromagnetic signal matrix in a preset format; Training and modeling the deviation effect of the electromagnetic signal matrix estimation variance to obtain a first symmetric matrix; Performing a similarity transformation on the first symmetric matrix, and calculating eigenvalues ​​of the transformed matrix; The signal arrival azimuth is set, and traversal is performed based on the matrix eigenvalue and the signal arrival azimuth to obtain a spatial domain incoming wave direction diagram.

9. The electromagnetic radiation on-site detection method based on spatial domain filtering according to claim 8, characterized in that: The method of performing beamforming calculation on the baseband signal by using the minimum variance distortion-free response algorithm to obtain a spatial domain filtering spectrum diagram includes: Determining an interference suppression direction from the spatial incoming wave direction diagram, and obtaining a steering vector according to the interference suppression direction; Performing a covariance matrix solving operation on the steering vector to obtain a second symmetric matrix; Inverting the diagonal loading matrix of the second symmetric matrix array and correcting the eigenvalues; Performing matrix multiplication and division operations based on the covariance matrix and the array steering vector to obtain a weight vector; The spatial domain filtering spectrum diagram is obtained by weighting and Fourier transforming the weight vector and the intermediate frequency signal.

10. The electromagnetic radiation on-site detection method based on spatial domain filtering according to claim 6, characterized in that: The step of adjusting the spacing between the array antennas to obtain an initial electromagnetic radiation signal within a preset frequency range includes: Initialize the spacing between antennas in the array antenna module; Calculating the power of half wavelength according to the preset frequency range; When the power of the half wavelength is within a preset reconstruction range, the spacing between antennas is adjusted according to the power of the half wavelength; otherwise, it is adjusted according to an integer multiple of the half wavelength to obtain an initial electromagnetic radiation signal in a preset frequency range.

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