An anti-interference method based on time-frequency domain data fusion

Abstract

The application discloses an anti-interference method based on time-frequency domain data fusion, and the process is as follows: sampling a received signal; processing the obtained sampling signal in two branches, wherein a frequency domain branch r f (n) is subjected to frequency domain anti-interference processing, and a time domain branch r t (n) is subjected to time domain anti-interference processing; the time domain branch signal r t (n) is subjected to time domain interference detection processing and time domain interference suppression processing; the frequency domain branch signal r f (n) is subjected to frequency domain interference detection processing and frequency domain interference suppression processing; data fusion is performed on the time domain and frequency domain anti-interference results obtained by the interference suppression processing by using the weight values obtained by the detection processing, so that a weighted overall anti-interference result is obtained. In the case of effectively resisting different signal domain strong interference, the application can still guarantee the integrity of the signal and good demodulation performance.

Description

Technical Field

[0001] This invention belongs to the field of data fusion and anti-interference technology, and relates to an anti-interference method based on time-frequency domain data fusion, which is applicable to receiver anti-interference processing under partial time-frequency domain interference. Background Technology

[0002] The demands for anti-interference capabilities in modern communications are constantly increasing. Systems need to maintain absolute reliability under strong interference, which places higher demands on their ability to resist strong interference across multiple domains in complex electromagnetic environments. To further improve the anti-interference capability of systems, especially their ability to resist different types of interference in the time and frequency domains, it is necessary to identify and process interference in the signal domain to achieve interference cancellation. Traditional signal domain processing methods are mostly limited to a single dimension, either the time or frequency domain. Some signal domain anti-interference measures that can simultaneously address two-dimensional time and frequency interference have weak anti-interference capabilities when both time and frequency domain interference are present, limiting their application scenarios in complex electromagnetic environments. Summary of the Invention

[0003] (I) Purpose of the Invention

[0004] The purpose of this invention is to address the problem of insufficient anti-interference capability of traditional technologies when both time-domain and frequency-domain interference exist simultaneously, and to propose an anti-interference method based on time-frequency domain data fusion.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, this invention provides an anti-interference method based on time-frequency domain data fusion, the implementation of which specifically includes the following steps:

[0007] Step 1: Sample the received signal. The sampled signal can be represented by the following formula (1):

[0008]

[0009] Where A represents the signal amplitude, T s Let be the time-domain sampling interval, and n be the sampling time, where n = 0, 1, ..., N-1. s(·) and s j (·) represent the useful signal and the interference signal, respectively, f d Indicates the carrier Doppler frequency. This is the initial phase of the carrier wave.

[0010] Step 2: Process the sampled signal obtained in Step 1 into two branches, one of which is the frequency domain branch r. f (n) Perform frequency domain anti-interference processing, time domain branch r t (n) Perform time-domain anti-interference processing. Specifically, as shown in formula (2):

[0011] r f (n)=r t (n)=r(n) (2)

[0012] Step 3: Analyze the time-domain branch signal r obtained in Step 2. t (n) Perform time-domain interference detection processing, specifically as follows:

[0013] Step 3.1 for r t (n) Take the modulo value and follow the period N t The average result is obtained by averaging the sampling points. Multiply the average result by the high threshold coefficient k th A high threshold T for time-domain interference detection can be obtained. th As shown in formula (3):

[0014]

[0015] Step 3.2 Determine N within the period t Does each sampling point exceed the high threshold T for time-domain interference detection? th If any sampling point exceeds the high threshold, it is determined that there is interference in the signal of that time-domain branch, and the weight α of that signal is adjusted accordingly. t Set to 1; if no sampling point exceeds the high threshold, it is determined that there is no interference in the signal of this time-domain branch, and the weight α of this signal is adjusted accordingly. t Set to 1000;

[0016] Step 4: Process the time-domain branch signal r obtained in Step 2. t (n) Perform time-domain interference suppression processing, specifically:

[0017] Step 4.1 Average the results obtained in Step 3.1 Multiply by the low threshold coefficient k tl The low threshold T for time-domain interference removal can be obtained. tl As shown in formula (4):

[0018]

[0019] Step 4.2 Determine N within the period t Does each sampling point exceed the low threshold T for time-domain interference removal? tl Record the positions where the interference removal threshold is exceeded, and record the time-domain branch signal r. t The amplitude at the same position of (n) is set to 0, and the time-domain anti-interference result is obtained.

[0020] Step 5: Analyze the frequency domain branch signal r obtained in Step 2. f (n) Perform frequency domain interference detection processing, specifically:

[0021] Step 5.1 for r f (n) according to a period of N f Perform FFT processing on each sampling point to obtain the frequency domain result R after FFT processing. f (n);

[0022] Step 5.2 for R f (n) Take the modulus value and then perform an average calculation to obtain the average result. Multiply the average result by the high threshold coefficient k fh A high threshold T for frequency domain interference detection can be obtained. fh As shown in formula (5):

[0023]

[0024] Step 5.3 Determine N f Does the FFT result exceed the high threshold T for frequency domain interference detection? fh If the threshold is exceeded, it is determined that there is interference in the signal of that frequency domain branch, and the weight α of that signal is adjusted. f Set to 1; if none exceed the high threshold, it is determined that there is no interference in the signal of this frequency domain branch, and the weight α of this signal is adjusted. f Set to 1000;

[0025] Step 6: Analyze the frequency domain branch signal r obtained in Step 2. f (n) Perform frequency domain interference suppression processing, specifically:

[0026] Step 6.1: Average the results obtained in Step 5.2 Multiply by the low threshold coefficient k fl The low threshold T for frequency domain interference removal can be obtained. fl As shown in formula (6):

[0027]

[0028] Step 6.2 Determine N f Does the FFT result exceed the low threshold T for frequency domain interference removal? fl Record the positions that exceed the interference removal threshold, and process the frequency domain result R obtained from the FFT in step 5.1. f The amplitude at the same position of (n) is set to 0, and the frequency domain interference removal result is obtained.

[0029] Step 6.3 According to the period N f IFFT processing is performed on each sampling point to obtain the frequency domain anti-interference result after IFFT processing.

[0030] Step seven, using the weight value a calculated in step three and step five t and a f , the time domain, frequency domain anti-interference results obtained in step four and step six Data fusion is performed on the anti-interference results to obtain the overall anti-interference result r j (n) represents as formula (7):

[0031]

[0032] (Three) beneficial effects

[0033] The anti-interference method based on time-frequency domain data fusion provided by the above technical solution has the following beneficial effects:

[0034] In order to overcome the problem that the traditional interference detection and elimination method has poor anti-interference effect when there are partial time and frequency domain interference at the same time, the present application uses high and low thresholds to detect and suppress interference in different signal domains, and performs weighted data fusion on the time and frequency domain anti-interference results. In the case of effectively resisting strong interference in different signal domains, the integrity of the signal and good demodulation performance can still be guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The processing flowchart of the anti-interference method based on time-frequency domain data fusion of the present application;

[0036] Figure 2 and Figure 3 are respectively the anti-interference effect diagrams of the anti-interference method based on time-frequency domain data fusion of the present application in the case of simultaneous existence of time and frequency domain partial interference. DETAILED DESCRIPTION

[0037] In order to make the purpose, content and advantages of the present application clearer, the specific embodiments of the present application will be further described in detail below in combination with the drawings and examples.

[0038] In order to overcome the problem that the traditional interference detection and elimination method has poor anti-interference effect when there are partial time and frequency domain interference at the same time, the present application proposes an anti-interference method based on time-frequency domain data fusion. By using high and low thresholds to detect and suppress interference in different signal domains, and performing weighted data fusion on the time and frequency domain anti-interference results, in the case of effectively resisting strong interference in different signal domains, the integrity of the signal and good demodulation performance can still be guaranteed.

[0039] Referring to Figure 1 , the anti-interference method based on time-frequency domain data fusion of the present embodiment includes the following steps in the implementation process:

[0040] Step one, sampling the received signal, the sampled signal can be expressed as formula (1) as follows:

[0041]

[0042] Wherein, A represents the signal amplitude, T s is the time domain sampling interval, n is the sampling time, and n = 0, 1, …, N-1. s(·) and s j (·) respectively represent the useful signal and the interference signal, f d represents the carrier Doppler frequency, is the carrier initial phase.

[0043] Step two, the sampling signal obtained in step one is processed in two branches, wherein the frequency domain branch r f (n) is subjected to frequency domain anti-interference processing, and the time domain branch r t (n) is subjected to time domain anti-interference processing. The specific expression is as formula (2) as follows:

[0044] r f (n) = r t (n) = r(n) (2)

[0045] Step three, the time domain branch signal r t (n) obtained in step two is subjected to time domain interference detection processing, which is specifically:

[0046] Step 3.1, the modulus value of r t (n) is taken, and the average processing is performed according to the period of N t sampling points, to obtain the average result The average result is multiplied by the high threshold coefficient k th , to obtain the high threshold T th of time domain interference detection, as formula (3) as follows:

[0047]

[0048] Step 3.2, it is judged whether the N t sampling points in the period exceed the high threshold T th of time domain interference detection, if there is a sampling point exceeding the high threshold, it is determined that the time domain branch signal has interference, and the weight value α t of the signal is set to 1; if there is no sampling point exceeding the high threshold, it is determined that the time domain branch signal has no interference, and the weight value α t of the signal is set to 1000;

[0049] Step four, the time domain branch signal r t (n) obtained in step two is subjected to time domain interference suppression processing, which is specifically:

[0050] Step 4.1 Average the results obtained in Step 3.1 Multiply by the low threshold coefficient k tl The low threshold T for time-domain interference removal can be obtained. tl As shown in formula (4):

[0051]

[0052] Step 4.2 Determine N within the period t Does each sampling point exceed the low threshold T for time-domain interference removal? tl Record the positions that exceed the interference removal threshold, and record the time-domain branch signal r. t The amplitude at the same position of (n) is set to 0, and the time-domain anti-interference result is obtained.

[0053] Step 5: Analyze the frequency domain branch signal r obtained in Step 2. f (n) Perform frequency domain interference detection processing, specifically:

[0054] Step 5.1 for r f (n) according to a period of N f Perform FFT processing on each sampling point to obtain the frequency domain result R after FFT processing. f (n);

[0055] Step 5.2 for R f (n) Take the modulus value and then perform an average calculation to obtain the average result. Multiply the average result by the high threshold coefficient k fh A high threshold T for frequency domain interference detection can be obtained. fh As shown in formula (5):

[0056]

[0057] Step 5.3 Determine N f Does the FFT result exceed the high threshold T for frequency domain interference detection? fh If the threshold is exceeded, it is determined that there is interference in the signal of that frequency domain branch, and the weight α of that signal is adjusted. f Set to 1; if none exceed the high threshold, it is determined that there is no interference in the frequency domain branch signal, and the weight α of this signal is adjusted. f Set to 1000;

[0058] Step 6: Analyze the frequency domain branch signal r obtained in Step 2. f (n) Perform frequency domain interference suppression processing, specifically:

[0059] Step 6.1: Average the results obtained in Step 5.2 Multiply by the low threshold coefficient k fl The low threshold T for frequency domain interference removal can be obtained.fl As shown in formula (6):

[0060]

[0061] Step 6.2 Determine N f Does the FFT result exceed the low threshold T for frequency domain interference removal? fl Record the positions that exceed the interference removal threshold, and process the frequency domain result R obtained from the FFT in step 5.1. f The amplitude at the same position of (n) is set to 0, and the frequency domain interference removal result is obtained.

[0062] Step 6.3 According to the period N f IFFT processing is performed on each sampling point to obtain the frequency domain anti-interference result after IFFT processing.

[0063] Step 7: Use the weights α calculated in Steps 3 and 5. t and α f The time-domain and frequency-domain anti-interference results obtained in steps four and six are... Perform data fusion to obtain the weighted overall anti-interference result r. j (n) represents the expression in formula (7):

[0064]

[0065] Thus, steps one through seven have completed the anti-interference mechanism based on time-frequency domain data fusion.

[0066] Figure 2 For frequency domain anti-interference effect, Figure 3 This refers to the time-domain anti-interference effect. (Refer to...) Figure 2 and Figure 3 The simulation input was a signal-to-interference ratio of 20 dB, with two types of interference signals: a frequency-domain comb interference with a frequency spacing of 1 MHz and an effective interference bandwidth of 200 kHz, and a time-domain pulse interference with a repetition period of 1 ms and a duty cycle of 20%. As shown in the figure, the locations of blocking interference in the time domain were correctly detected, and after the interference suppression process, the amplitude at the locations of interference was set to zero. Similarly, the locations of blocking interference in the frequency domain were also correctly detected, and after the interference suppression process, the amplitude at the locations of interference was set to zero.

[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An anti-interference method based on time-frequency domain data fusion, characterized in that, The method comprises the following steps: Step one, sampling the received signal; Step two, the sampling signal obtained in step one is divided into two branches, one of which is a frequency domain branch signal r f (n), and the other is a time domain branch signal r t (n). Step three, time domain branch signal r t (n) performing time domain interference detection processing, and calculating the weight value corresponding to the branch signal; Step four, performing time domain interference suppression processing on the time domain branch signal r t (n) performing time domain interference suppression processing; Step five, frequency domain interference detection processing is performed on the frequency domain branch signal r f (n) frequency domain interference detection processing is performed, and the weight value corresponding to the branch signal is calculated; Step six, frequency domain interference suppression processing is performed on the frequency domain branch signal r f (n) performing frequency domain interference suppression processing; Step seven, using the weight values calculated in step three and step five to perform data fusion on the time domain and frequency domain anti-interference results obtained in step four and step six to obtain a weighted overall anti-interference result.

2. The anti-jamming method based on time-frequency domain data fusion according to claim 1, characterized in that, In step one, the sampled signal is represented by formula (1): where A denotes the signal amplitude, T s is the time-domain sampling interval, n is the sampling time, and n = 0, 1, …, N-1; s(·) and s j (·) denote the useful signal and the interference signal, respectively, f d denotes the carrier Doppler frequency, is the carrier initial phase.

3. The anti-jamming method based on time-frequency domain data fusion according to claim 2, characterized in that, In step two, the relationship of the branch signals is: r f (n) = r t (n) = r(n) (2).

4. The anti-jamming method based on time-frequency domain data fusion according to claim 3, characterized in that, The process of step three is: Step 3.1 r t (n) take the modulus value and average the result t (n) take the modulus value and average the result (n) take the modulus value and average the result th (n) take the modulus value and average the result th (n) take the modulus value and average the result Step 3.2 judge whether N t sampling points in a period exceed the high threshold T th of time domain interference detection, if there is a sampling point exceeding the high threshold, it is determined that the time domain branch signal has interference, and the weight α t of the signal is set to 1; If no sample point exceeds the high threshold, it is determined that the time-domain branch signal does not have interference, and the weight α of the signal is set to 1 t is set to 1000.

5. The anti-jamming method based on time-frequency domain data fusion according to claim 4, characterized in that, In step 3.1, high threshold T of time domain interference detection th As shown in equation (3):

6. The anti-jamming method based on time-frequency domain data fusion according to claim 5, characterized in that, The process of step four is: Step 4.1 Average the results from Step 3.1 Multiply by low threshold coefficient k tl The low threshold T for time domain interference cancellation is obtained tl As shown in equation (4): Step 4.2 judge whether N t sampling points in a period exceed the low threshold T tl of time domain interference elimination t , record the positions exceeding the interference elimination threshold, and set the amplitude of the same position of the time domain branch signal r 7. The anti-jamming method based on time-frequency domain data fusion according to claim 6, characterized in that, The process of step five is: Step 5.1 r f (n) is the FFT result of the N f sample points, and R f (n) is the FFT result of the N sample points. Step 5.2 to R f (n) take the modulus value, and average processing, get the average result to the average result multiplied by the high threshold coefficient k fh , get the high threshold T of frequency domain interference detection fh ; Step 5.3 Determine N f Does the FFT result exceed the high threshold T for frequency domain interference detection? fh If the threshold is exceeded, it is determined that there is interference in the signal of that frequency domain branch, and the weight α of that signal is adjusted. f Set to 1; if none exceed the high threshold, it is determined that there is no interference in the signal of this frequency domain branch, and the weight α of this signal is adjusted. f Set to 1000.

8. The anti-jamming method based on time-frequency domain data fusion according to claim 7, characterized in that, In step 5.2, high threshold T of frequency domain interference detection fh As shown in equation (5):

9. The anti-jamming method based on time-frequency domain data fusion according to claim 8, characterized in that, The process of step six is: Step 6.1 Average the results from step 5.2 Multiply by low threshold coefficient k fl Low threshold T for frequency domain interference deletion is obtained fl As shown in formula (6): Step 6.2 Determine N f Does the FFT result exceed the low threshold T for frequency domain interference removal? fl Record the positions that exceed the interference removal threshold, and process the frequency domain result R obtained from the FFT in step 5.

1. f The amplitude at the same position of (n) is set to 0, and the frequency domain interference removal result is obtained. Step 6.3 pair IFFT processing is performed on N f sample points, and the frequency domain anti-interference result after IFFT processing is obtained 10. The anti-jamming method based on time-frequency domain data fusion according to claim 9, characterized in that, The weighted overall anti-interference result r in step seven j (n) represents as formula (7):

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