Intermittent sampling and forwarding interference signal identification method and parameter estimation method

Abstract

The invention discloses an intermittent sampling and forwarding interference signal identification and parameter estimation method, which comprises the following steps of: for four different types of intermittent sampling and forwarding interferences, preliminarily judging whether the interferences are intermittent sampling and forwarding interferences and specific forwarding types or not according to the characteristics of the interferences in a time domain envelope; estimating interference signal parameters according to the over-threshold mark of the interference time domain envelope and the number of spectrum peaks of the interference frequency domain spectrum; according to the method, accurate type identification can be carried out on intermittent sampling direct forwarding, repeated forwarding, cyclic forwarding and superimposed forwarding interference in real time; according to the invention, accurate parameter estimation of sampling pulse width, sampling pulse period, slice number and forwarding frequency can be carried out on intermittent sampling forwarding interference in real time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of radar electronic countermeasure, and particularly relates to an intermittent sampling and retransmission jamming signal identification method and a parameter estimation method. BACKGROUND

[0002] The intermittent sampling and retransmission jamming is an electronic countermeasure means for making false targets by intermittently sampling, slicing and retransmitting radar signals to interfere with radar detection, which can produce many false targets at different positions and distances, has the effects of deception and suppression on the radar at the same time, and shields and covers the real targets.

[0003] By accurately judging the type of intermittent sampling jamming and measuring the jamming parameters, the radar can deduce the working mode of the jammer, and then implement anti-jamming. In actual combat application, the radar usually needs to make decisions in microseconds, but the type identification and parameter estimation of the intermittent sampling and retransmission jamming are mostly based on time-frequency analysis or image recognition, neural network and other intelligent methods, and there are few researches based on engineering practice, so the practicability is poor in real reconnaissance scenes. SUMMARY

[0004] Therefore, the purpose of the present application is to provide an intermittent sampling and retransmission jamming signal identification and parameter estimation method to solve the problem that the existing electronic reconnaissance receiver technology cannot simultaneously identify and estimate the interference fine granularity when performing reconnaissance on the intermittent sampling and retransmission jamming signal.

[0005] An intermittent sampling and retransmission jamming signal identification method, comprising:

[0006] Firstly, time domain envelope feature identification is performed, specifically: for the signal over the detection threshold, if the measured time domain envelope is smooth and the duty cycle is less than 50%, the type is determined as direct retransmission jamming; if the measured time domain envelope is smooth and the duty cycle is greater than 50%, the type is determined as repeated retransmission jamming; if the measured time domain envelope is smooth and the duty cycle experiences the process of increasing, maintaining unchanged and decreasing, the type is determined as cyclic retransmission jamming; and if the measured time domain envelope is not smooth, the type is initially determined as superimposed retransmission jamming;

[0007] Further, frequency domain spectrum feature identification is performed, specifically: the FFT mode is used to extract the spectrum information of the pulse over the threshold, the maximum value detection is performed on each FFT result, and half of the maximum value in the result is taken as a threshold, if greater than the threshold, it is regarded as a spectrum peak in the spectrum, and finally the number of spectrum peaks is recorded;

[0008] If the number of spectrum peaks is stable at 1, the type is determined as direct retransmission interference; if the number of spectrum peaks is stable at 2, the type is determined as repeated retransmission interference; if the number of spectrum peaks experiences an increasing, constant, and decreasing process, and the minimum is 1, the type is determined as cyclic retransmission interference; if the number of spectrum peaks experiences an increasing, constant, and decreasing process, and the minimum is 2, the type is determined as cyclic retransmission interference.

[0009] Finally, if the time-domain envelope feature recognition result and the frequency-domain spectrum feature recognition result are inconsistent, when the frequency-domain result is cyclic retransmission interference or superimposed retransmission interference, the frequency-domain result is used as the criterion; when the frequency-domain result is direct retransmission interference or repeated retransmission interference, the time-domain result is used as the criterion.

[0010] Preferably, when the time-domain envelope feature recognition is performed, the signal power is compared with a threshold power P 门限 , and after pulse splitting and merging, a threshold-crossing mark is obtained; during the threshold-crossing period of the signal, the echo signal is considered to exist; finally, the signal power is compared with a secondary threshold, and the envelope and duty cycle features of the intermittent sampling retransmission interference are obtained, which are used for the time-domain envelope feature recognition.

[0011] Preferably, the threshold power P 门限 is calculated as k·P 噪声 +delta. 门限 P 噪声 represents the noise power, k and delta respectively represent an adjustment factor and a bias compensation factor, and are both constants; the average power of the echo signal is calculated, and then a secondary threshold P 二次门限 is calculated as k0·P r +delta0. P s represents the average power of the signal during the threshold-crossing period, and k0 and delta0 respectively represent an adjustment factor and a bias compensation factor, and are both constants.

[0012] Preferably, the method further comprises an interference parameter estimation method, which specifically comprises:

[0013] The duration from the rising edge to the falling edge of the secondary threshold-crossing mark of the intermittent sampling retransmission interference signal is detected as the sampling pulse width of each sub-pulse.

[0014] During the duration of the intermittent sampling retransmission interference signal, all the sampling pulse width values are recorded, and the average value of the stable part is selected as the sampling pulse width T r of the interference signal.

[0015] Preferably, the method further comprises an interference parameter estimation method, which specifically comprises:

[0016] The duration from the rising edge to the next rising edge of the secondary threshold-crossing mark of the intermittent sampling retransmission interference signal is detected as the sampling period of each sub-pulse.

[0017] During the duration of the intermittent sampling and retransmission jamming signal, record all the sampling period values, select the stable part to obtain the average value as the sampling period T of the jamming signal s .

[0018] Preferably, it further includes an interference parameter estimation method, specifically:

[0019] After detecting the change of the rising edge to the falling edge of the twice threshold crossing mark of the intermittent sampling and retransmission jamming signal, the number of slices is increased by 1; during the duration of the intermittent sampling and retransmission jamming signal, until the end of this jamming, the number of slices of the jamming signal is obtained.

[0020] Preferably, it further includes an interference parameter estimation method, specifically:

[0021] When it is determined to be intermittent sampling and repeated retransmission jamming, FFT is performed on each jamming sub-pulse that crosses the threshold to obtain its spectrum information, the highest and the second highest spectrum peaks are detected, the interval between the two spectrum peaks is calculated and then the reciprocal is obtained, the sampling pulse width of the intermittent sampling and repeated retransmission jamming is obtained, denoted as t r ; the sub-pulse width T r of the intermittent sampling and repeated retransmission jamming is obtained through time domain envelope information, and the repetition number N of the intermittent sampling and repeated retransmission jamming is calculated according to r .

[0022] Preferably, it further includes an interference parameter estimation method, specifically:

[0023] After it is determined to be intermittent sampling and cyclic retransmission jamming, the first sub-pulse width T r1 of the intermittent sampling and cyclic retransmission jamming is obtained through time domain envelope information, the sub-pulse width is stable when it is T r , and the cycle number N of the intermittent sampling and cyclic retransmission jamming is calculated according to c ; at the same time, after it is determined to be intermittent sampling and cyclic retransmission jamming, the maximum number of spectrum peaks of the sub-pulse frequency domain spectrum information is obtained, that is, the cycle number N c ; when the results of the time domain and the frequency domain are stable, the frequency domain measurement result is used as the criterion.

[0024] Preferably, it further includes an interference parameter estimation method, specifically:

[0025] After it is determined to be intermittent sampling and superimposed retransmission jamming, the maximum number of spectrum peaks of the sub-pulse frequency domain spectrum information is obtained, that is, N f , and the superimposed number N of the intermittent sampling and superimposed retransmission jamming is calculated according to s .

[0026] The present application has the following beneficial effects:

[0027] The present application is directed to four different types of intermittent sampling retransmission interference, firstly according to the characteristics of the time domain envelope to preliminarily distinguish whether it is intermittent sampling retransmission interference and the specific retransmission type, and then according to the over-threshold mark of the interference time domain envelope and the number of interference frequency domain spectrum peaks to estimate the interference signal parameters; the present application can accurately identify the type of intermittent sampling direct retransmission, repeated retransmission, cyclic retransmission and superimposed retransmission interference in real time; the present application can accurately estimate the sampling pulse width, sampling pulse period, slice number and retransmission number of the intermittent sampling retransmission interference in real time. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Specific process for intermittent sampling retransmission interference identification and parameter measurement;

[0029] Figure 2 Envelope of intermittent sampling direct retransmission interference signal (without noise);

[0030] Figure 3 Envelope of intermittent sampling repeated retransmission interference signal (without noise);

[0031] Figure 4 Envelope of intermittent sampling cyclic retransmission interference signal (without noise);

[0032] Figure 5 Envelope of intermittent sampling superimposed retransmission interference signal (without noise);

[0033] Figure 6 Single sub-pulse spectrum of intermittent sampling direct retransmission interference;

[0034] Figure 7 Single sub-pulse spectrum of intermittent sampling repeated retransmission interference;

[0035] Figure 8 is a single sub-pulse spectrum of intermittent sampling cyclic retransmission interference;

[0036] Figure 9 is a single sub-pulse spectrum of intermittent sampling superimposed retransmission interference;

[0037] Figure 10 Sampling pulse width estimation of intermittent sampling retransmission interference signal;

[0038] Figure 11 Sampling period estimation of intermittent sampling retransmission interference signal;

[0039] Figure 12 Slice number estimation of intermittent sampling retransmission interference signal. DETAILED DESCRIPTION

[0040] The present application will be described in detail below with reference to the accompanying drawings and examples.

[0041] The specific implementation method and process are as follows: Figure 1 As shown, intermittent sampling forwarding interference manifests as multiple dense narrow pulse signals in the time domain. The pulse width of the radar transmitted signal is used as known prior information. When a signal power exceeding a threshold is detected, the pulse width of the radar transmitted signal is used as the detection window for intermittent sampling forwarding interference. If the number of pulse signals exceeding the threshold within the detection window is greater than the set threshold, then intermittent sampling forwarding interference is considered to exist; otherwise, intermittent sampling forwarding interference does not exist.

[0042] After detecting intermittent sampling and forwarding interference, the time-domain envelope, duty cycle, and frequency-domain spectral peak count features are extracted to determine the type of interference. If the time-domain and frequency-domain determination results are inconsistent, the frequency-domain result shall prevail if the frequency-domain determination is cyclic forwarding or superimposed forwarding, and the time-domain determination result shall prevail if the frequency-domain determination is direct forwarding or repeated forwarding.

[0043] Meanwhile, the sampling pulse width, sampling period, number of slices, and number of repetitions are measured by measuring the time domain envelope and duty cycle, and the number of cycles or superpositions (depending on the type of interference) is measured by measuring the number of frequency domain spectral peaks. Finally, the measurement results are formed by framing.

[0044] 1. Temporal envelope feature recognition

[0045] This invention extracts the envelope and duty cycle features of intermittent sampling forwarding interference using a quadratic threshold method, serving as one of the criteria for identifying the interference type. Compared to time-frequency analysis, image recognition, neural networks, or other intelligent methods, this approach fully utilizes time-domain information, achieving higher resolution and thus distinguishing four types of interference.

[0046] According to P 门限 =k·P 噪声 +delta calculates the gate limit power P 门限 ;

[0047] P 噪声 The noise power is represented by k and delta, which are constants and represent the adjustment factor and bias compensation factor, respectively. This is compared with the signal, and after pulse splitting and combining, a threshold mark is obtained. The signal crossing the threshold is considered to have an echo signal; the average power of the echo signal is calculated, and then... Calculate the quadratic threshold P 二次门限 , The signal average power during the threshold period is represented by k0 and delta, which are constants and represent the adjustment factor and bias compensation factor, respectively. Finally, the signal is compared with the secondary threshold to obtain the envelope and duty cycle characteristics of the intermittent sampling forwarding interference, and the interference type is identified by the different time-domain characteristics of the four forwarding modes. In this embodiment, k and k0 are approximately 2 or 3, and delta and delta are approximately 100 or 200.

[0048] The characteristics of the intermittent sampling retransmission interference of the four different retransmission modes are different in the time domain envelope, which can be used as one of the constraints for type identification. The characteristics of the intermittent sampling direct retransmission interference in the time domain envelope satisfy that the envelope amplitude fluctuates smoothly, and the sub-pulse duty cycle is less than 50%, as shown in Figure 2 The characteristics of the intermittent sampling repeated retransmission interference in the time domain envelope satisfy that the envelope amplitude fluctuates smoothly, and the sub-pulse duty cycle is greater than 50%, as shown in Figure 3 The characteristics of the intermittent sampling cyclic retransmission interference in the time domain envelope satisfy that the envelope amplitude fluctuates smoothly, the sampling pulse width increases by a fixed width, then remains unchanged, and finally decreases by the same fixed width, as shown in Figure 4 The characteristics of the intermittent sampling superimposed retransmission interference in the time domain envelope satisfy that the pulse envelope of the superimposed part has a large amplitude fluctuation, the envelope form is similar to the cos function, and the sub-pulse duty cycle is greater than 50%, as shown in Figure 5 .

[0049] According to the above characteristics, if the measured time domain envelope is smooth and the duty cycle is less than 50%, the type is determined as direct retransmission; if the measured time domain envelope is smooth and the duty cycle is greater than 50%, the type is determined as repeated retransmission; if the measured time domain envelope is smooth and the duty cycle experiences the process of increasing, remaining unchanged and decreasing, the type is determined as cyclic retransmission; and if the measured time domain envelope is not smooth, the type is preliminarily determined as superimposed retransmission.

[0050] 2. Frequency domain spectrum feature identification

[0051] The present application extracts the spectrum information by performing FFT on the over-threshold pulse. Compared with time-frequency analysis or image recognition, neural network and other intelligent methods, this method can utilize the time domain over-threshold information, reduce the noise influence, and has better identification effect.

[0052] Since the research background of the present application is the narrowband linear frequency modulation echo interference when a radar tracks a target, the signal bandwidth obtained by intermittently sampling the retransmission interference of the original radar signal is very small, and when the spectrum analysis is performed, it can be regarded as a single point frequency signal. The FFT is performed on the signal pulse of each over-threshold, and the point number is determined by the signal pulse length (the point number is set to be a power of 2, and if the signal point number is insufficient, zero is supplemented). The maximum value detection is performed on each FFT result, and half of the maximum value in the result is taken as a threshold, if it is greater than the threshold, it is regarded as a spectrum peak in the spectrum, and finally the number of spectrum peaks is recorded.

[0053] The characteristics of the intermittent sampling retransmission interference of the four different retransmission modes are different in the frequency domain spectrum, which can be used as one of the constraints for type identification. The spectrum of each sub-pulse of the intermittent sampling direct retransmission interference only has one spectrum peak, as shown in Figure 6 The spectrum of each sub-pulse of the intermittent sampling repeated retransmission interference has two spectrum peaks with different amplitudes, as shown inFigure 7 As shown in Figure 8, the sub-pulse spectrum of intermittent sampling cyclic forwarding interference has multiple spectral peaks with the same amplitude, and the number of spectral peaks gradually increases, then remains constant, and then gradually decreases, with the minimum number of spectral peaks being 1. The spectrum of intermittent sampling repeated forwarding interference, after being superimposed, has multiple spectral peaks with different amplitudes, and the number of spectral peaks gradually increases, then remains constant, and then gradually decreases, with the minimum number of spectral peaks being 2.

[0054] Based on the above characteristics, if the number of measured spectral peaks is consistently 1, the type is identified as direct forwarding; if the number of measured spectral peaks is consistently 2, the type is identified as repeated forwarding; if the number of measured spectral peaks goes through a process of increasing, remaining unchanged, and decreasing, and the minimum is 1, the type is identified as cyclic forwarding; if the number of measured spectral peaks goes through a process of increasing, remaining unchanged, and decreasing, and the minimum is 2, the type is identified as cyclic forwarding.

[0055] 3. Intermittent sampling and forwarding interference parameter estimation method

[0056] Intermittent sampling and forwarding interference estimates interference sampling parameters based on the signal's time-domain envelope characteristics, mainly including interference sampling pulse width, interference sampling period, and the number of interference slices; and estimates interference forwarding parameters based on the frequency-domain spectral characteristics of the signal sub-pulses, mainly including the number of repeated forwardings, the number of cyclic forwardings, and the number of superimposed forwardings. Intermittent sampling and forwarding interference has many slices and a small pulse width, reaching the 0.5µs level, which is almost impossible to identify by time-frequency analysis or intelligent methods such as image recognition and neural networks. The method adopted in this invention can utilize the signal's time-domain and frequency-domain information to the greatest extent possible to achieve accurate measurement of interference parameters.

[0057] After detection and preprocessing, radar jamming signals can obtain threshold markers for their corresponding time moments, which are equivalent to idealized time-domain envelopes. These threshold markers are then used to estimate and measure the sampling pulse width, sampling period, and number of slices.

[0058] (1) Sampling pulse width

[0059] like Figure 10 As shown, the duration from the rising edge to the falling edge of the threshold mark of the intermittent sampling forwarding interference signal is used as the sampling pulse width of each sub-pulse.

[0060] During the duration of an intermittent sampling and relaying interference signal, all sampling pulse width values ​​are recorded, and the average value of the stable portions is taken as the sampling pulse width T of this interference signal. r .

[0061] (2) Sampling period

[0062] like Figure 11As shown, the duration from the rising edge of the second threshold mark to the next rising edge of the intermittent sampling forwarding interference signal is used as the sampling period for each sub-pulse.

[0063] During a single intermittent sampling and relaying of an interference signal, all sampling period values ​​are recorded, and the average of the stable portions is taken as the sampling period T of this interference signal. s .

[0064] (3) Number of slices

[0065] like Figure 12 As shown, after detecting the change from the rising edge to the falling edge of the threshold mark for the intermittent sampling and forwarding interference signal, the number of slices is incremented by 1.

[0066] During the continuous process of intermittent sampling and forwarding of the interference signal until the end of the interference, the number of slices of the interference signal is obtained.

[0067] (4) Number of repetitions

[0068] Once it is determined to be intermittent sampling and repetitive forwarding interference, an FFT is performed on each interfering subpulse that crosses the threshold to obtain its spectral information. The highest and second highest spectral peaks are detected, the interval between the two spectral peaks is calculated, and then the reciprocal is taken to obtain the sampling pulse width of the intermittent sampling and direct forwarding interference, denoted as t. r The sub-pulse width T of the intermittent sampling repeated forwarding interference can be obtained through the time-domain envelope information. r ,according to The number of repetitions N for intermittent sampling and repeated forwarding interference is calculated. r .

[0069] (5) Number of cycles

[0070] After confirming that it is intermittent sampling cyclic forwarding interference, the width of the first sub-pulse of the intermittent sampling cyclic forwarding interference is obtained as T using the time-domain envelope information. r1 When the sub-pulse width is stable, it is T. r ,according to The number of cycles N for intermittent sampling cyclic forwarding interference was calculated. c .

[0071] Meanwhile, after determining that it is intermittent sampling cyclic forwarding interference, the maximum number of spectral peaks obtained from the sub-pulse frequency domain spectrum information is the cycle number N. c When both time-domain and frequency-domain results are stable, the frequency-domain measurement result shall prevail.

[0072] (6) Number of stackings

[0073] After determining that the interference was caused by intermittent sampling superimposed on forwarding, the maximum number of spectral peaks was determined to be N using the sub-pulse frequency domain spectrum information. f ,according to The number of superpositions N of the intermittent sampling superposition retransmission interference is calculated s .

[0074] To sum up, the above is only the preferred embodiment of the present application, not for limiting the scope of protection of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An intermittent sampling and forwarding jamming signal identification method, characterized in that, Comprise: First, time domain envelope feature recognition is carried out, further, frequency domain spectrum feature recognition is carried out, finally, if time domain envelope feature recognition result and frequency domain spectrum feature recognition result are inconsistent, when frequency domain discrimination is cyclic forwarding interference or superimposed forwarding interference, frequency domain result is used as the criterion, when frequency domain discrimination is direct forwarding interference or repeated forwarding interference, time domain discrimination result is used as the criterion.

2. The intermittent sampling forwarding interference signal recognition method of claim 1, characterized in that, The time domain envelope feature recognition comprises: for the signal over the detection threshold, if the measured time domain envelope is stable and the duty cycle is less than 50%, the type discrimination is direct forwarding interference; if the measured time domain envelope is stable and the duty cycle is greater than 50%, the type discrimination is repeated forwarding interference; if the measured time domain envelope is stable and the duty cycle experiences the process of increasing, remaining unchanged and decreasing, the type discrimination is cyclic forwarding interference; if the measured time domain envelope is unstable, the type preliminary discrimination is superimposed forwarding interference; The frequency domain spectrum feature recognition specifically comprises: the frequency spectrum information is extracted by the FFT mode for the threshold pulse, the maximum value detection is carried out for each FFT result, and the half of the maximum value in the result is taken as the threshold, if greater than the threshold, it is regarded as the spectrum peak in the frequency spectrum, and finally the spectrum peak number is recorded; If the measured spectrum peak number is stable as 1, the type discrimination is direct forwarding interference; if the measured spectrum peak number is stable as 2, the type discrimination is repeated forwarding interference; if the measured spectrum peak number experiences the process of increasing, remaining unchanged and decreasing, and the minimum is 1, the type discrimination is cyclic forwarding interference; if the measured spectrum peak number experiences the process of increasing, remaining unchanged and decreasing, and the minimum is 2, the type discrimination is cyclic forwarding interference.

3. An intermittent sampling and forwarding jammer signal identification method as claimed in claim 2, characterized in that, In the time domain envelope feature recognition, the signal power is compared with a threshold power P 门限 After comparison and pulse splitting and merging, the over-threshold flag is obtained. The signal over the threshold is regarded as existing echo signal during the signal; finally, the signal power is compared with the secondary threshold, the envelope and the duty cycle characteristics of the intermittent sampling forwarding interference can be obtained, which are used for the time domain envelope feature recognition.

4. An intermittent sampling and forwarding jammer signal identification method as claimed in claim 3, characterized in that, Threshold power P 门限 = k - P 噪声 + delta 门限 ; P 噪声 represents noise power, k and delta respectively represent adjustment factor and bias compensation factor, both are constants; average power of echo signal is calculated, and then threshold P 二次门限 , represents average power of signal during over threshold period, k0 and delta0 respectively represent adjustment factor and bias compensation factor, both are constants.

5. The method of claim 3, wherein the method further comprises: Further comprising an interference parameter estimation method, specifically: The duration from the rising edge of the secondary threshold mark of the intermittent sampling forwarding interference signal to the falling edge is detected as the sampling pulse width of each sub-pulse; During the process of intermittent sampling and retransmission of jamming signal, all the sampling pulse width values are recorded, and the average value of the stable part is selected as the sampling pulse width T of the jamming signal r .

6. The method of claim 3, wherein the method further comprises: Further comprising an interference parameter estimation method, specifically: The duration from the rising edge of the secondary threshold mark of the intermittent sampling forwarding interference signal to the next rising edge is detected as the sampling period of each sub-pulse; During the process of intermittent sampling and forwarding jamming signal, record all the sampling period values, select the stable part to calculate the average value as the sampling period T of this jamming signal s .

7. The method of claim 3, wherein the method further comprises: Further comprising an interference parameter estimation method, specifically: After detecting the change from the rising edge of the secondary threshold mark of the intermittent sampling forwarding interference signal to the falling edge, the slice number is added by 1; in the duration of one intermittent sampling forwarding interference signal, until the end of this interference, the slice number of this interference signal is obtained.

8. The method of claim 3, wherein the method further comprises: Further comprising an interference parameter estimation method, specifically: Once it is determined to be intermittent sampling and repetitive forwarding interference, an FFT is performed on each interfering subpulse that crosses the threshold to obtain its spectral information. The highest and second highest spectral peaks are detected, the interval between the two spectral peaks is calculated, and then the reciprocal is taken to obtain the sampling pulse width of the intermittent sampling and direct forwarding interference, denoted as t. r The sub-pulse width T of the intermittent sampling repeated forwarding interference is obtained through the time-domain envelope information. r ,according to The number of repetitions N for intermittent sampling and repeated forwarding interference is calculated. r .

9. The method of claim 3, wherein the method further comprises: Further comprising an interference parameter estimation method, specifically: After confirming that it is intermittent sampling cyclic forwarding interference, the width of the first sub-pulse of the intermittent sampling cyclic forwarding interference is obtained as T using the time-domain envelope information. r1 When the sub-pulse width is stable, it is T. r ,according to The number of cycles N for intermittent sampling cyclic forwarding interference was calculated. c Simultaneously, after determining that it is intermittent sampling cyclic forwarding interference, the maximum number of spectral peaks obtained from the sub-pulse frequency domain spectrum information is the cycle number N. c When both time-domain and frequency-domain results are stable, the frequency-domain measurement result shall prevail.

10. The method of claim 3, wherein the method further comprises: Further comprising an interference parameter estimation method, specifically: After determining that it is intermittent sampling superposition retransmission interference, the maximum number of spectral peaks of the intermittent sampling superposition retransmission interference is N through sub-pulse frequency domain spectrum information f . According to , the superposition number N of the intermittent sampling superposition retransmission interference is calculated s .

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