Adaptive interference suppression method, device and system based on time domain background modeling

Abstract

This invention discloses an adaptive interference suppression method, apparatus, and system based on temporal background modeling, relating to the field of target detection radar technology. The method includes: S1 acquiring a continuous signal and dividing it into discrete frame signal vectors; S2 determining whether the current frame is the initial frame; if so, initializing and obtaining the initial frame background; otherwise, updating the temporal background estimation vector; S3 analyzing the difference signal; S4 estimating the background noise standard deviation; S5 analyzing the adaptive limiting threshold and defining the adaptive limiting function; S6 limiting the difference signal; and S7 reconstructing the limited difference signal to output the interference-suppressed signal. Through temporal background modeling and difference extraction, interference and target separation are achieved in the signal processing domain. This method operates entirely in the time domain, avoiding signal loss due to the overlap of the interference and target spectra. The spectral characteristics of the target signal are fully preserved, ensuring the accuracy of subsequent ranging, angle measurement, and other processing.

Description

Technical Field

[0001] This invention relates to the field of target detection radar technology, and in particular to an adaptive interference suppression method, apparatus and system based on time-domain background modeling. Background Technology

[0002] In complex environments, target detection radar is used for the detection and localization of projectile targets. Due to the presence of multiple targets and multiple interference sources, severe co-frequency asynchronous interference occurs. This interference is highly sudden, appears randomly in time, and has a significantly higher amplitude than the target echo. Furthermore, it exhibits temporal overlap and spectral aliasing, overlapping with the target echo in both the time and frequency domains. Traditional time-division filtering fails, and frequency-domain filtering leads to the loss of target information.

[0003] Current common interference suppression methods have significant shortcomings in dealing with co-frequency and asynchronous interference: Traditional frequency domain filtering methods suppress interference in specific frequency bands through filter banks or adaptive filtering, but co-frequency interference completely overlaps with the target spectrum, and frequency domain separation will result in the loss of target information, making them unsuitable for the high-precision measurement requirements of target detection radar. Spatial domain processing-based methods use array antennas for beamforming or spatial filtering, which are effective against directional interference, but cannot suppress co-frequency radar interference from the same or similar directions, and are costly and complex. Time domain detection and elimination methods identify interference pulses through threshold detection and perform zeroing or interpolation. However, in dense interference environments, the elimination of multiple consecutive sampling points will lead to severe distortion of the target echo waveform, significantly reducing ranging and velocity measurement accuracy and increasing the probability of false targets. Traditional background cancellation methods use recursive averaging or sliding window averaging with fixed coefficients to estimate the background, but when the coefficients are too large, the background update is slow and cannot adapt to environmental changes; when the coefficients are too small, strong interference pulses "contaminate" the background estimation, leading to false alarms in subsequent frames.

[0004] Existing technologies cannot effectively suppress large-amplitude, randomly occurring, and spectrally overlapping synchronous and asynchronous interference while maintaining the integrity of the target signal, resulting in a sharp decline in the performance of target detection radar in complex electromagnetic environments such as dense formations. Summary of the Invention

[0005] The purpose of this invention is to design an adaptive interference suppression method, device, and system based on time-domain background modeling to solve the above problems.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] An adaptive interference suppression method based on temporal background modeling includes:

[0008] S1. Acquire the continuous signal received by the radar and divide it into discrete frame signal vectors according to the pulse repetition interval. Obtain signal sequence , is represented as: ,in, k is the frame index, and M is the number of frames. It is the set of real numbers;

[0009] S2. Determine if the current frame is the initial frame. If so, initialize the background to obtain the initial frame background. Then proceed to S3; otherwise, update the temporal background estimation vector. Then enter S3;

[0010] S3, based on the current frame signal and the background of the previous frame Obtain the difference signal vector Where k is the signal of the kth frame;

[0011] S4, Based on difference signal vector Estimate the standard deviation of background noise , is represented as: med is the median;

[0012] S5. Based on standard deviation Analyze the adaptive limiting threshold p and define the adaptive limiting function. , is represented as: , ,in, is the preset threshold coefficient, and x is the independent variable of the adaptive limiting function;

[0013] S6. Using an adaptive amplitude limiting threshold p to adjust the difference signal vector Amplification is performed to obtain the amplitude-limited difference signal vector. , is represented as: ;

[0014] S7. Reconstruct the difference signal vector after amplitude limiting and output the signal after interference suppression.

[0015] An adaptive interference suppression device based on time-domain background modeling includes:

[0016] Storage; storage is used to store computer programs;

[0017] An actuator; the actuator is used to execute a computer program stored in a memory, which, when executed, implements the adaptive interference suppression method based on temporal background modeling as described above.

[0018] An adaptive interference suppression system based on time-domain background modeling includes:

[0019] Acquisition terminal; The acquisition terminal is used to acquire continuous signals received by the radar;

[0020] Data processing end; The data processing end uses the adaptive interference suppression method based on time-domain background modeling as described above to process the continuous signal and obtain the interference-suppressed signal;

[0021] Output terminal; the output terminal is used to output the signal after interference suppression.

[0022] The beneficial effects of this invention are as follows: by using time-domain background modeling and difference extraction, interference and the target are separated in the signal processing domain; this method operates entirely in the time domain, avoiding signal loss caused by the overlap of the interference and target spectra. The spectral characteristics of the target signal are fully preserved, ensuring the accuracy of subsequent ranging, angle measurement, and other processing. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the adaptive interference suppression method based on temporal background modeling of the present invention;

[0024] Figure 2 This is a schematic diagram of a signal containing noise and interference;

[0025] Figure 3 This is a schematic diagram of the signal's time-domain background;

[0026] Figure 4 This is a schematic diagram of the difference between the unlimited signal after background cancellation;

[0027] Figure 5 It is the difference signal after amplitude limiting. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0035] like Figure 1 As shown, the adaptive interference suppression method based on temporal background modeling includes:

[0036] S1. Acquire the continuous signal received by the radar and divide it into discrete frame signal vectors according to the pulse repetition interval. Obtain signal sequence , is represented as: ,in, k is the frame index, and M is the number of frames. It is the set of real numbers.

[0037] S2. Determine if the current frame is the initial frame. If so, initialize the background to obtain the initial frame background. , is represented as: Then proceed to S3; otherwise, update the temporal background estimation vector. , is represented as: Then enter S3; among them, As a forgetting factor, let A negative integer power of 2 is represented as: ;but Where N is the number of bits, This is a right shift operation. The value of N is a positive integer, and under normal sea conditions, the value of the number of digits N ranges from 2 to 6.

[0038] S3, based on the current frame signal and the background of the previous frame Obtain the difference signal vector , is represented as: Where k is the signal of the kth frame; the difference signal vector Includes target echo component Background noise components and sudden interference components Then the difference signal ;

[0039] S4, Based on difference signal vector Estimate the standard deviation of background noise , is represented as: med is the median;

[0040] S5. Based on standard deviation Analyze the adaptive limiting threshold p and define the adaptive limiting function. , is represented as: , ,in, is the preset threshold coefficient, and x is the independent variable of the adaptive limiting function;

[0041] Preset threshold coefficient The value range is 3-5, and the specific values ​​are:

[0042] Assuming background noise The target signal amplitude is The interference amplitude is In the case of only noise, the difference signal The probability of being limited is: ;in, , It is a normal distribution. The standard deviation of the normal distribution. The variance of the normal distribution A function to calculate the probability of being amplitude-limited. Let e ​​be the base of the natural number, for Noise limiting rate 0.27%, Noise limiting rate: 0.0063%. The noise limiting rate is approximately 0%. In the case of a target signal, The condition for the target not to be incorrectly limited is: ;in To provide a protection margin (typically 1-2 dB), the condition for effective interference suppression in the presence of a target signal is: ;therefore It can achieve a good balance between suppressing interference and protecting the target.

[0043] S6. Using an adaptive amplitude limiting threshold p, the difference signal vector is adjusted according to the adaptive amplitude limiting function. Amplification is performed to obtain the amplitude-limited difference signal vector. , is represented as: ;

[0044] S7. Reconstruct the difference signal vector after clipping. The reconstructed difference signal... Represented as: The signal after interference suppression Represented as: .

[0045] The adaptive interference suppression method based on temporal background modeling proposed in this invention has the following beneficial effects:

[0046] By employing temporal background modeling and difference extraction, interference and target separation are achieved in the signal processing domain. This method operates entirely in the time domain, avoiding signal loss caused by the overlap of the interference and target spectra. The spectral characteristics of the target signal are fully preserved, ensuring the accuracy of subsequent ranging and angle measurement. This method adopts a fully fixed-point arithmetic architecture, eliminating multiplication and floating-point operations, requiring only shift and addition / subtraction operations. It can be directly mapped to shift registers and adder chains in FPGA, meeting the real-time requirements of target detection radar. This method is highly robust against environmental changes and interference, employing a dual adaptive mechanism (adaptive background update rate and adaptive amplitude limiting threshold) to cope with complex electromagnetic environments, providing a feasible signal processing solution for high-density radar deployment. This method effectively reduces the impact of co-frequency asynchronous interference on the integrity of FMCW radar signals. By separating sparse interference components through temporal background modeling and amplitude limiting processing, while maintaining the main structure of the continuous wave, only a very small number of sampling points are subject to limited correction, maximizing the preservation of the phase continuity and linearity of the high duty cycle frequency-modulated signal, thus ensuring ranging accuracy.

[0047] An adaptive interference suppression device based on time-domain background modeling includes:

[0048] Storage; storage is used to store computer programs;

[0049] An actuator; the actuator is used to execute a computer program stored in a memory, which, when executed, implements the adaptive interference suppression method based on temporal background modeling as described above.

[0050] An adaptive interference suppression system based on time-domain background modeling includes:

[0051] Acquisition terminal; The acquisition terminal is used to acquire continuous signals received by the radar;

[0052] Data processing end; The data processing end uses the adaptive interference suppression method based on time-domain background modeling as described above to process the continuous signal and obtain the interference-suppressed signal;

[0053] Output terminal; the output terminal is used to output the signal after interference suppression.

[0054] Example: Set the number of signal simulation frames to 2048, use a sine wave signal as the normal signal, set the hard limiting threshold to 200 (approximately 8 times the standard deviation), set the interference pulse amplitude to 1000 (5 times the normal signal), and set it to appear randomly within 20% PRI. The system update coefficient is 1 / 32.

[0055] Using the above parameters, adaptive interference suppression is applied to the signal using this method, and the results are as follows: Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, where Figure 2 The signal is a noisy and interfering signal, containing fixed leakage (sine component) and white noise, while the burst interference pulse (amplitude 1000) has a short duration but a very large amplitude; Figure 3 For the estimated time-domain background, the leakage signal was successfully extracted from the background, and transient components of noise and interference were filtered out; Figure 4 As can be seen, the interference was successfully separated into the differential signal, but the amplitude was still large. After clipping, the signal amplitude in the interference area decreased from 1000 to 200, with a suppression ratio of 14dB. In the non-interference area, the signal shape remained almost unchanged, and the background transitioned smoothly without abrupt changes. Figure 5 As shown in the figure. In summary, this method successfully suppresses sudden interference while maintaining signal integrity. The algorithm has simple complexity, is suitable for hardware implementation, and can adapt to interference under different interference densities and noise environments, exhibiting good robustness. This invention enables the system to simultaneously achieve optimal performance in three dimensions: interference suppression depth, target fidelity, and real-time performance, solving the problem that traditional methods cannot achieve simultaneously. Simulation results are highly consistent with theoretical analysis, demonstrating the engineering feasibility and technical advantages of this method.

[0056] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. An adaptive interference suppression method based on temporal background modeling, characterized in that, include: S1. Acquire the continuous signal received by the radar and divide it into discrete frame signal vectors according to the pulse repetition interval. Obtain signal sequence , is represented as: ,in, k is the frame index, and M is the number of frames. It is the set of real numbers; S2. Determine if the current frame is the initial frame. If so, initialize the background to obtain the initial frame background. Then proceed to S3; otherwise, update the temporal background estimation vector. Then enter S3; S3, based on the current frame signal and the background of the previous frame Obtain the difference signal vector Where k is the signal of the kth frame; S4, Based on difference signal vector Estimate the standard deviation of background noise , is represented as: med is the median; S5. Based on standard deviation Analyze the adaptive limiting threshold p and define the adaptive limiting function. , is represented as: , ,in, is the preset threshold coefficient, and x is the independent variable of the adaptive limiting function; S6. Using an adaptive amplitude limiting threshold p to adjust the difference signal vector Amplification is performed to obtain the amplitude-limited difference signal vector. , is represented as: ; S7. Reconstruct the difference signal vector after amplitude limiting and output the signal after interference suppression.

2. The adaptive interference suppression method based on temporal background modeling according to claim 1, characterized in that, In S2, the background is initialized to obtain the initial frame background estimation vector, which is represented as follows: Where L represents the previous L frames, S j This is the signal of the j-th frame.

3. The adaptive interference suppression method based on temporal background modeling according to claim 1, characterized in that, Update the temporal background estimation vector Represented as: , As a forgetting factor, let A negative integer power of 2 is represented as: ;but Where N is the number of bits, This is a right shift operation. It is a positive integer.

4. The adaptive interference suppression method based on temporal background modeling according to claim 1, characterized in that, In S3, the difference signal vector Represented as: ,in, It is a forgetting factor.

5. The adaptive interference suppression method based on temporal background modeling according to claim 1, characterized in that, In S7, the reconstructed difference signal Represented as: The signal after interference suppression Represented as: ,in, It is a forgetting factor.

6. The adaptive interference suppression method based on temporal background modeling according to claim 1, characterized in that, Under normal sea conditions, the value of the number of bits N ranges from 2 to 6, with a preset threshold coefficient. The value range is 3-5.

7. An adaptive interference suppression device based on time-domain background modeling, characterized in that, include: Storage; Storage is used to store computer programs; Actuator; The actuator is used to execute a computer program stored in the memory, which, when executed, implements the adaptive interference suppression method based on temporal background modeling as described in any one of claims 1-6.

8. An adaptive interference suppression system based on time-domain background modeling, characterized in that, include: Data acquisition end; The acquisition unit is used to acquire continuous signals received by the radar; Data processing end; The data processing end uses the adaptive interference suppression method based on time-domain background modeling as described in any one of claims 1-6 to process the continuous signal and obtain the interference-suppressed signal. Output terminal; the output terminal is used to output the signal after interference suppression.

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