Ultra-wideband ultra-narrow strong electromagnetic pulse signal acquisition and processing system

Abstract

The invention belongs to the technical field of detection and identification, and particularly relates to an ultra-wideband ultra-narrow strong electromagnetic pulse signal acquisition and processing system, which comprises a signal acquisition module; and the signal processing module is used for carrying out ultrahigh-speed acquisition and processing on the acquired strong electromagnetic pulse signal, realizing acquisition and processing on a signal with extremely narrow pulse width of 3.4 ns, and adopting a specific signal calibration and real-time compensation algorithm. Identification of the narrow-spectrum high-power microwave signal, the ultra-wide-spectrum high-power microwave signal and the high-power radar signal is realized; and the protection module adopts a high-power attenuator to protect a system radio frequency channel so as to simultaneously collect large signals and small signals. Through specific signal calibration and real-time compensation algorithm optimization, accurate identification of the signals is realized, and through protection design of a high-power attenuator and the like, measurement of 5V / m-50kV / m field intensity signals and endurance capability of 100kV / m field intensity are both considered.

Description

Technical Field

[0001] This invention belongs to the field of detection and identification technology, specifically relating to an ultra-wideband, extremely narrow, strong electromagnetic pulse signal acquisition and processing system. Background Technology

[0002] With the rapid development and widespread deployment of radar and communication facilities at home and abroad, technologies such as electronic warfare, spectrum warfare and electromagnetic pulse attacks are constantly evolving. In addition, the electromagnetic environment in which ships, aircraft and other platforms frequently approach and interact with surrounding ships and aircraft in their daily operations is becoming increasingly harsh, complex and changeable. This can easily lead to the failure or loss of function of critical systems / equipment on the platform, and even threaten the safety of use.

[0003] However, existing electromagnetic environment monitoring technologies have significant shortcomings and are insufficient to meet the operational requirements of equipment platforms in highly dynamic environments: Existing electric field measurement methods cannot respond quickly to rapidly changing electromagnetic signals and are difficult to acquire electromagnetic information in a short time within an ultra-wide frequency band (such as 30MHz~20GHz), thus failing to meet the full-band monitoring requirements in complex electromagnetic environments. Existing electromagnetic environment monitoring equipment has limited tolerance to large signal inputs. When it approaches a high-power emission source or faces an electromagnetic pulse attack, it is easily damaged due to signal overload, resulting in the inability to record strong electromagnetic pulse signal information that is extremely threatening to the platform. Existing monitoring methods generally suffer from problems such as long measurement time, weak transient signal capture capability, and small dynamic range, making it difficult to effectively acquire and process strong electromagnetic pulse signals with extremely narrow pulse widths (such as 3.4ns), and also unable to meet the requirements of high real-time electromagnetic environment analysis.

[0004] Therefore, developing a technical solution that can adapt to ultra-wide frequency bands, withstand strong electromagnetic pulses, and achieve high real-time acquisition and processing is of great significance for filling the current gap in the field of strong electromagnetic pulse signal monitoring and supporting the electromagnetic protection and safe operation of equipment. Summary of the Invention

[0005] To address the technical problems of existing monitoring methods, such as long measurement time, weak transient signal capture capability, and small dynamic range, this invention provides an ultra-wideband, extremely narrow-range, high-intensity electromagnetic pulse signal acquisition and processing system.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A system for acquiring and processing ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signals includes: The signal acquisition module adopts a technology system that combines direct radio frequency acquisition and superheterodyne, and is used to acquire strong electromagnetic pulse signals in the 30MHz-20GHz frequency band. The strong electromagnetic pulse signals include narrow-spectrum high-power microwave signals, ultra-wide-spectrum high-power microwave signals, and high-power radar signals. The direction-finding module, employing a time-difference direction-finding system, is used to determine the direction of the strong electromagnetic pulse signal; The signal processing module is used to perform ultra-high-speed acquisition and processing of the acquired strong electromagnetic pulse signal, realize the acquisition and processing of the signal with an extremely narrow pulse width of 3.4ns, and use a specific signal calibration and real-time compensation algorithm to realize the identification of the narrow-spectrum high-power microwave signal, the ultra-wide-spectrum high-power microwave signal and the high-power radar signal. The protection module uses a high-power attenuator to protect the system's radio frequency channel, so as to ensure the simultaneous acquisition of both large and small signals.

[0007] In the signal acquisition module, signals in the 30MHz-2GHz frequency band are acquired using direct RF acquisition, while signals in the 1.5GHz-20GHz frequency band are acquired using a direct IQ mixing superheterodyne method, converted to four IQ baseband signals of DC-2GHz, and then acquired. The two RF signals output by the antenna array are attenuated and power divided before analog-to-digital conversion. The digital processing module of the detection processor completes pulse detection, time difference extraction, and amplitude comparison. The obtained pulse descriptor and pulse parameter measurement results are sent to the detection and analysis sentry via the network interface for direction calculation, display, and alarm.

[0008] The direction-finding module includes an antenna array containing two or three elements. With two elements, it can perform direction finding in the forward ±75° direction, while with three elements, it can perform omnidirectional 360° direction finding. The direction-finding module calculates the direction of arrival of the signal by calculating the time difference between the arrival points of the signal and the antenna elements. The time difference Δt = LTs, where L is the number of sliding points and T is the distance between the antenna elements. s The sampling period is set; the time difference estimation result is corrected according to the system time difference error correction parameter, the directionality of the signal is calculated, and the image direction finding result is removed to eliminate direction finding ambiguity by comparing the signal amplitudes output by the two directional antennas and the receiving channel.

[0009] The signal processing module is based on channelized high-speed electromagnetic pulse signal acquisition and processing technology. It uses multiple high-capacity FPGAs to perform fully parallel and pipelined processing on the acquired signals to achieve real-time detection and parameter measurement of full-bandwidth signals. The signal processing module performs pulse signal post-processing on the acquired signals, including pulse signal descriptor estimation, pulse signal intra-pulse feature analysis, and pulse signal storage.

[0010] The signal processing module includes a pulse detection and extraction unit. The pulse detection and extraction unit uses a combination of adaptive threshold and time-domain energy detection to detect pulse signals and extracts pulse signals from the signal buffer based on the pulse detection results. The signal detection uses a detection algorithm based on digital channelization to perform adaptive threshold detection on blindly sampled pulse data. The digital channelization processing is based on short-time Fourier transform (STFT).

[0011] The mathematical expression for the STFT-based digital channelization processing is as follows: in: Let L be a window function with length N, L be the number of sliding points, n be the time point, and k be the channel number. This represents the frequency domain result of the k-th channel at time n; the window function length is N, and the number of FFT points is the same as the window width, also N. The input continuous digital signal, after data processing and windowing filtering, is segmented and sent to the FFT module for frequency domain information analysis, enabling continuous spectral analysis of the sampled data and real-time output of the analysis results; the frequency domain resolution is [value missing]. ,in This represents the input signal bandwidth.

[0012] In the adaptive threshold detection, let z(n) represent the signal of a certain subchannel after digital channelization processing and square-law detection, and its mathematical model is: in: To determine the detection threshold, the method for estimating the threshold involves taking a certain amount of data at the pulse-free points in each data segment, calculating its mean, and then iteratively calculating the mean against previous statistical results. The calculation formula is: , where a is the iteration coefficient, g(n) is the mean of the current values, and h(n-1) is the result of previous statistical calculations.

[0013] The protection module includes a radio frequency front-end pre-selection protection module, which performs amplitude limiting and signal equalization, and can withstand electromagnetic pulses with a field strength of up to 100kV / m. At the same time, it detects and measures the parameters of electromagnetic pulse signals with a field strength of 5V / m-50kV / m. The radio frequency front-end pre-selection protection module combines the antenna output signals of two sets of 30MHz~2GHz and 1.5GHz~20GHz through a combiner and outputs them to the radio frequency receiving module.

[0014] It also includes a time and frequency module, which contains a BeiDou receiving antenna and a corresponding processing module, used to provide time and frequency references for the entire system, and can be synchronized with an external 10MHz system reference clock, and provides two 10MHz and four 100MHz reference clock outputs.

[0015] In the signal processing module, the STFT channelization method divides the bandwidth B of the input signal into N sub-channels. For signal detection, a frequency domain detection method is used, defined as detecting the FFT output of each window function. This represents the power in the k-th sub-channel at time n. The presence or absence of a signal is detected by comparing it with a set threshold. in This is the detection threshold for the k-th sub-channel.

[0016] Compared with the prior art, the beneficial effects of this invention are: This invention achieves effective acquisition of strong electromagnetic pulse signals (including narrow-spectrum high-power microwaves, ultra-wide-spectrum high-power microwaves, and high-power radar signals) within an ultra-wide frequency band of 30MHz to 20GHz by employing a combination of radio frequency direct acquisition and superheterodyne technology. It breaks through the limitations of channelization-based ultra-high-speed acquisition and processing technology, enabling the processing of signals with extremely narrow pulse widths of 3.4ns. Simultaneously, it utilizes a time-difference direction finding system to address the inaccuracy of interferometer-based direction finding for narrow-spectrum / ultra-wide-spectrum high-power microwave signals. Through specific signal calibration and real-time compensation algorithm optimization, it achieves accurate identification of the aforementioned signals. Furthermore, by utilizing protective designs such as high-power attenuators, it balances the measurement of field strength signals from 5V / m to 50kV / m with the ability to withstand field strengths up to 100kV / m. This fills the current technological gap in high-power microwave signal acquisition and direction finding, providing key technical support for active defense against strong electromagnetic pulses and significantly improving the safety and mission reliability of equipment in complex electromagnetic environments. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0018] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0019] Figure 1This is a block diagram of the radio frequency module circuit design of the present invention; Figure 2 A block diagram of the digital processing module of this invention; Figure 3 This is the processing flow for pulse signal extraction and analysis according to the present invention; Figure 4 This is a flowchart of the pulse signal detection module of the present invention; Figure 5 This is a schematic diagram of the STFT-based digital channelization principle of the present invention; Figure 6 This is a flowchart of the time difference direction finding process of the present invention; Figure 7 This is a schematic diagram of the antenna co-pillar erection of the present invention; Figure 8 This is a block diagram of the radio frequency receiving module of the present invention; Figure 9 This is a block diagram of the digital processing board of the present invention; Figure 10 This is a block diagram of the time-frequency module of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. These descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the claims of the present invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0022] like Figure 7 As shown, the antenna array of this invention adopts a shared-pole mounting method, including one 30MHz~2GHz biconical antenna and one 1.5GHz~20GHz biconical antenna. The mounting position can be adjusted according to site conditions to achieve ultra-wideband signal reception coverage. The two RF signals output by the antenna array are attenuated and power divided before entering the RF receiving module.

[0023] like Figure 8As shown, the RF receiving module processes the input signal in two segments: the 30MHz to 2GHz band uses direct RF sampling, directly conditioning the signal before sending it to the digital processing module; the 1.5GHz to 20GHz band undergoes segmented filtering, amplification, attenuation, and other conditioning before being converted into four IQ baseband signals (DC to 2GHz) via IQ mixing by the local oscillator baseband module and then entering the digital processing module. The RF front-end pre-selection protection module integrates limiting and signal equalization functions, uses a high-power attenuator to achieve RF channel protection, can withstand electromagnetic pulses with a field strength of 100kV / m, and effectively detects signals with a field strength of 5V / m to 50kV / m. Figure 1 The circuit design of the RF module is shown.

[0024] like Figure 9 As shown, the digital processing module adopts a hardware architecture of 2 FPGAs + 1 ADC: the ADC performs analog-to-digital conversion on the input baseband signal, and the FPGA receives the digital signal, performs buffering and fully parallel, fully pipelined processing, and transmits it to the backplane via a high-speed bus. The collaborative work of multiple high-capacity FPGAs ensures real-time processing of signals with a full bandwidth of 30MHz to 20GHz, and in particular, realizes the acquisition and processing of signals with an extremely narrow pulse width of 3.4ns.

[0025] Signal processing flow as follows Figure 3 As shown: The radio frequency (RF) signal received by the antenna array is transmitted to the direction-finding processor via RF cables. It first undergoes amplitude limiting and frequency band filtering conditioning, and then high-speed analog-to-digital conversion and pulse detection are performed by a multi-channel digital processing module. When a high-energy pulse signal is detected, the pulse data is extracted from the buffer, and pulse descriptor estimation, intra-pulse feature analysis, and storage are performed. The pulse detection and extraction process employs... Figure 4 The process shown is implemented based on digital channelization and adaptive threshold detection: Digital channelization processing is based on STFT, such as Figure 5 As shown, its mathematical expression is: In the formula, Let L be a window function of length N, L be the number of sliding points, n be the time point, and k be the channel number. This represents the frequency domain result of the k-th channel at time n. The input signal, after windowing filtering, is segmented and fed into the FFT module to achieve continuous spectrum analysis, with a frequency domain resolution of [value missing]. ( (Input signal bandwidth), time domain resolution is ( (Sampling period).

[0026] In adaptive threshold detection, let z(n) be the signal after square law detection, and the detection model is: in To detect the threshold, an iterative algorithm is used. ( For iteration coefficients, This is the average value for this period. (Based on historical results) Dynamically adjusted. Frequency domain detection is achieved through comparison. With threshold Implement signal presence / absence determination: The direction finding module uses a time-difference direction finding system, such as Figure 8 As shown, a 2-element antenna provides forward direction finding within ±75°, while a 3-element antenna achieves omnidirectional direction finding. The time difference of the signal arrival at each element is calculated. The direction of arrival is calculated, and the results are corrected by combining the system time difference error correction parameters. The amplitude of the antenna output signal is compared to eliminate the ambiguity value of the direction finding, and finally the correct direction finding is output.

[0027] Time and frequency modules, such as Figure 10 As shown, it includes a BeiDou receiving antenna and processing module, provides time and frequency references, can be synchronized with an external 10MHz reference clock, and outputs two 10MHz and four 100MHz reference clocks to provide synchronization clock support for modules such as radio frequency reception and digital processing.

[0028] This embodiment, through the above structure and process, achieves ultra-wideband acquisition, ultra-high-speed processing, accurate direction finding, and reliable protection of strong electromagnetic pulse signals from 30MHz to 20GHz, verifying the effectiveness of the present invention.

[0029] The above description only illustrates the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A system for acquiring and processing ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signals, characterized in that: include: The signal acquisition module adopts a technology system that combines direct radio frequency acquisition and superheterodyne, and is used to acquire strong electromagnetic pulse signals in the 30MHz-20GHz frequency band. The strong electromagnetic pulse signals include narrow-spectrum high-power microwave signals, ultra-wide-spectrum high-power microwave signals, and high-power radar signals. The direction-finding module, employing a time-difference direction-finding system, is used to determine the direction of the strong electromagnetic pulse signal; The signal processing module is used to perform ultra-high-speed acquisition and processing of the acquired strong electromagnetic pulse signal, realize the acquisition and processing of the signal with an extremely narrow pulse width of 3.4ns, and use a specific signal calibration and real-time compensation algorithm to realize the identification of the narrow-spectrum high-power microwave signal, the ultra-wide-spectrum high-power microwave signal and the high-power radar signal. The protection module uses a high-power attenuator to protect the system's radio frequency channel, so as to ensure the simultaneous acquisition of both large and small signals.

2. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 1, characterized in that, In the signal acquisition module, signals in the 30MHz-2GHz frequency band are acquired using direct RF acquisition, while signals in the 1.5GHz-20GHz frequency band are acquired using a direct IQ mixing superheterodyne method, converted to four IQ baseband signals of DC-2GHz, and then acquired. The two RF signals output by the antenna array are attenuated and power divided before analog-to-digital conversion. The digital processing module of the detection processor completes pulse detection, time difference extraction, and amplitude comparison. The obtained pulse descriptor and pulse parameter measurement results are sent to the detection and analysis sentry via the network interface for direction calculation, display, and alarm.

3. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 1, characterized in that, The direction-finding module includes an antenna array containing two or three elements. With two elements, it can perform direction finding in the forward ±75° direction, while with three elements, it can perform omnidirectional 360° direction finding. The direction-finding module calculates the direction of arrival of the signal by calculating the time difference between the arrival times of the signal and the antenna elements, where the time difference Δt = LT. s Where L is the number of sliding points, T s The sampling period is set; the time difference estimation result is corrected according to the system time difference error correction parameter, the directionality of the signal is calculated, and the image direction finding result is removed to eliminate direction finding ambiguity by comparing the signal amplitudes output by the two directional antennas and the receiving channel.

4. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 1, characterized in that, The signal processing module is based on channelized high-speed electromagnetic pulse signal acquisition and processing technology. It uses multiple high-capacity FPGAs to perform fully parallel and pipelined processing on the acquired signals to achieve real-time detection and parameter measurement of full-bandwidth signals. The signal processing module performs pulse signal post-processing on the acquired signals, including pulse signal descriptor estimation, pulse signal intra-pulse feature analysis, and pulse signal storage.

5. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 4, characterized in that, The signal processing module includes a pulse detection and extraction unit. The pulse detection and extraction unit uses a combination of adaptive threshold and time-domain energy detection to detect pulse signals and extracts pulse signals from the signal buffer based on the pulse detection results. The signal detection uses a detection algorithm based on digital channelization to perform adaptive threshold detection on blindly sampled pulse data. The digital channelization processing is based on short-time Fourier transform (STFT).

6. The ultra-wideband, extremely narrow-range, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 5, characterized in that, The mathematical expression for the STFT-based digital channelization processing is as follows: in: Let L be a window function with length N, L be the number of sliding points, n be the time point, and k be the channel number. This represents the frequency domain result of the k-th channel at time n; the window function length is N, and the number of FFT points is the same as the window width, also N. The input continuous digital signal, after data processing and windowing filtering, is segmented and sent to the FFT module for frequency domain information analysis, enabling continuous spectral analysis of the sampled data and real-time output of the analysis results; the frequency domain resolution is [value missing]. ,in This represents the input signal bandwidth.

7. The ultra-wideband, extremely narrow-range, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 5, characterized in that, In the adaptive threshold detection, let z(n) represent the signal of a certain subchannel after digital channelization processing and square-law detection, and its mathematical model is: in: To determine the detection threshold, the method for estimating the threshold involves taking a certain amount of data at the pulse-free points in each data segment, calculating its mean, and then iteratively calculating the mean against previous statistical results. The calculation formula is: , where a is the iteration coefficient, g(n) is the mean of the current values, and h(n-1) is the result of previous statistical calculations.

8. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 1, characterized in that, The protection module includes a radio frequency front-end pre-selection protection module, which performs amplitude limiting and signal equalization, and can withstand electromagnetic pulses with a field strength of up to 100kV / m. At the same time, it detects and measures the parameters of electromagnetic pulse signals with a field strength of 5V / m-50kV / m. The radio frequency front-end pre-selection protection module combines the antenna output signals of two sets of 30MHz~2GHz and 1.5GHz~20GHz through a combiner and outputs them to the radio frequency receiving module.

9. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 1, characterized in that, It also includes a time and frequency module, which contains a BeiDou receiving antenna and a corresponding processing module, used to provide time and frequency references for the entire system, and can be synchronized with an external 10MHz system reference clock, and provides two 10MHz and four 100MHz reference clock outputs.

10. The ultra-wideband, extremely narrow-band, high-intensity electromagnetic pulse signal acquisition and processing system according to claim 1, characterized in that, In the signal processing module, the STFT channelization method divides the bandwidth B of the input signal into N sub-channels. For signal detection, a frequency domain detection method is used, defined as detecting the FFT output of each window function. This represents the power in the k-th sub-channel at time n. The presence or absence of a signal is detected by comparing it with a set threshold. in This is the detection threshold for the k-th sub-channel.

Images