Anti-intermittent sampling interference method based on Otsu's method of random orthogonal subpulses

Abstract

This invention discloses a method for combating intermittent sampling interference based on Otsu's method for random orthogonal subpulses. The method includes: establishing intra-pulse and inter-pulse randomly coded orthogonal frequency modulated waveform models; encoding and orthogonally frequency modulating intra-pulse and inter-pulse subpulses to obtain compressed subpulses; obtaining the inter-class variance of the compressed subpulses according to a multi-level Otsu algorithm; obtaining an optimal threshold based on the inter-class variance of the compressed subpulses; and determining the difference between the target signal and three types of intermittent sampling interference signals based on the optimal threshold. This invention can improve the accuracy of identifying and distinguishing the target signal and the three types of intermittent sampling forwarding interference signals, effectively combating intermittent sampling forwarding interference.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, and in particular to a method for resisting intermittent sampling interference based on the Otsu method of random orthogonal subpulses. Background Technology

[0002] Radar jamming and counter-jamming have been a fiercely contested battleground since the advent of radar, evolving into a continuous struggle between offense and defense. Radar jamming patterns are categorized into suppression jamming and deceptive jamming. Suppression jamming is easily detected by radar and often cannot be coherently or non-coherently accumulated. More importantly, suppression jamming is easily detected due to its large transmission power and suppressed bandwidth, meaning it is "attacked as soon as it's turned on." Currently, radars have many methods to counter suppression jamming, such as intra-pulse and inter-pulse frequency modulation and polarization cancellation. Deceptive jamming, on the other hand, creates false targets that closely resemble the real target to achieve a deceptive effect. Radars often need to tailor their countermeasures to deceptive jamming; there is no one-size-fits-all method. With the development of high-speed storage and high-speed signal acquisition theories and the continuous improvement of corresponding device performance, digital radio frequency memory technology can be used to intercept radar transmitted signals and then forward them according to a certain strategy, thereby forming an echo that is very similar to the real target. Moreover, it can mask the echo of the real target in terms of power. Since it is an interception of the transmitted signal, the intermittent sampling and forwarding interference is still coherent interference. This means that it is difficult for radar to weaken the interference through intra-pulse or inter-pulse coherent accumulation, which brings great challenges to radar target detection and tracking.

[0003] Unlike high-power, wide-bandwidth suppression jamming, intermittent sampling-forward jamming, as a form of deceptive jamming, employs a "small effort, big result" approach and a "using the enemy's own weapon against them" strategy. It partially intercepts the radar's transmitted signal, then carefully modulates it before relaying it back to the radar. Intermittent sampling-forward jamming comes in various forms; by adjusting the modulation method and parameters, it can create highly realistic, controllable, and geographically configurable active false targets. Traditional coherent pulse radars have low waveform parameter freedom and poor low interception rate. When countering intermittent sampling-forward jamming, the design of the anti-jamming signal has limited freedom, resulting in poor effectiveness and, in severe cases, even radar incapacitation. Most existing anti-intermittent sampling-forward jamming methods distinguish between the target signal and the intermittent sampling-forward jamming signal, but fail to differentiate between different types of intermittent sampling-forward jamming. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method for resisting intermittent sampling interference based on the Otsu method of random orthogonal subpulses, so as to improve the recognition rate of intermittent sampling forwarding interference.

[0005] One aspect of this invention provides a method for resisting intermittent sampling interference based on the Otsu method of random orthogonal subpulses, the method comprising:

[0006] Establish a random coded orthogonal frequency modulation waveform model for intra-pulse and inter-pulse sub-pulses, and perform coded orthogonal frequency modulation on intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses;

[0007] Based on the multi-level Otsu algorithm, the inter-class variance of the compressed sub-pulse is obtained, and the optimal threshold is obtained based on the inter-class variance of the compressed sub-pulse.

[0008] The difference between the target signal and the three intermittent sampling interference signals is determined based on the optimal threshold.

[0009] Optionally, the intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform model is as follows:

[0010]

[0011] In the formula, S(t) represents the intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform, N represents the number of pulses transmitted by the radar, P represents the number of sub-pulses in each pulse, and S(t,n,m) represents the expression of the m-th sub-pulse in the n-th pulse.

[0012] Optionally, obtaining the inter-class variance of the compressed sub-pulses based on the multi-level Otsu algorithm, and obtaining the optimal threshold based on the inter-class variance of the compressed sub-pulses, includes:

[0013] Obtain the absolute value of the time-domain variance of the sub-pulse after compression for each echo signal, and arrange the absolute values ​​into a target array;

[0014] The threshold is obtained based on the target array;

[0015] Iterate through all thresholds to find the optimal threshold.

[0016] Optionally, obtaining the threshold based on the target array includes:

[0017] The first data point is selected from the target array to obtain the first-level threshold, thus forming the first sub-interval.

[0018] Based on the target array, a second data point is selected to obtain the second-level threshold, forming the second sub-interval;

[0019] Based on the target array, a third data point is selected to obtain the third-level threshold, forming the third sub-interval;

[0020] A fourth sub-interval is formed based on the data of the target array, the first sub-interval, the second sub-interval, and the third sub-interval.

[0021] Optionally, the loop iterating through all thresholds to obtain the optimal threshold includes:

[0022] Calculate the probability of the occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval;

[0023] Calculate the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval;

[0024] The inter-class variance is defined based on the probability of occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval, as well as the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval.

[0025] Iterate through all thresholds until the maximum inter-class variance is obtained, thus obtaining the optimal threshold.

[0026] The formula for calculating the probability of the first sub-interval occurring is:

[0027]

[0028] The formula for calculating the probability of the second sub-interval occurring is:

[0029]

[0030] The formula for calculating the probability of the third sub-interval occurring is:

[0031]

[0032] The formula for calculating the probability of the fourth sub-interval occurring is:

[0033]

[0034] In the formula, w1 represents the probability of the first sub-interval occurring, w2 represents the probability of the second sub-interval occurring, w3 represents the probability of the third sub-interval occurring, w4 represents the probability of the fourth sub-interval occurring, i represents the first data, j represents the second data, k represents the third data, 4NP represents the size of the target array, where N represents the number of pulses emitted by the radar, and P represents the number of sub-pulses within each pulse;

[0035] The formula for calculating the average amplitude of the first sub-interval is:

[0036]

[0037] The formula for calculating the average amplitude of the second sub-interval is:

[0038]

[0039] The formula for calculating the average amplitude of the third sub-interval is as follows:

[0040]

[0041] The formula for calculating the average amplitude of the fourth sub-interval is as follows:

[0042]

[0043] The formula for calculating the average amplitude of the total interval is:

[0044]

[0045] In the formula, λ1 represents the average amplitude of the first sub-interval, λ2 represents the average amplitude of the second sub-interval, λ3 represents the average amplitude of the third sub-interval, λ4 represents the average amplitude of the fourth sub-interval, λ represents the average amplitude of the total interval, and Var represents the target array.

[0046] The formula for the inter-class variance is:

[0047]

[0048] In the formula, σ 2 w represents the inter-class variance. h λ represents the probability of a subinterval occurring. h λ represents the average amplitude of the sub-interval, and λ represents the average amplitude of the total interval.

[0049] The optimal threshold expression is:

[0050]

[0051] In the formula, T1 * T2 * T3 * T1 represents the first-level threshold, T2 represents the second-level threshold, and T3 represents the third-level threshold.

[0052] This invention also provides an anti-intermittent sampling interference device based on the Otsu method of random orthogonal subpulses, comprising:

[0053] The first module is used to establish intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform models, and to encode and orthogonally frequency modulate intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses.

[0054] The second module is used to obtain the inter-class variance of the compressed sub-pulse based on the multi-level Otsu algorithm, and to obtain the optimal threshold based on the inter-class variance of the compressed sub-pulse.

[0055] The third module is used to determine the difference between the target signal and the three intermittent sampling interference signals based on the optimal threshold.

[0056] Optionally, the second module is used to obtain the inter-class variance of the compressed sub-pulses according to the multi-level Otsu algorithm, and to obtain the optimal threshold based on the inter-class variance of the compressed sub-pulses, including:

[0057] The first submodule is used to obtain the absolute value of the time-domain variance of the subpulse compression corresponding to each echo signal, and arrange the absolute values ​​into a target array;

[0058] The second submodule is used to obtain the threshold based on the target array;

[0059] The third submodule is used to iterate through all thresholds to obtain the optimal threshold.

[0060] Optionally, the third submodule, used to iterate through all thresholds to obtain the optimal threshold, includes:

[0061] The first unit is used to calculate the probability of the occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval;

[0062] The second unit is used to calculate the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval;

[0063] The third unit is used to define the inter-class variance based on the probability of occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval, as well as the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval.

[0064] The fourth unit is used to iterate through all thresholds until the maximum inter-class variance is obtained, thus yielding the optimal threshold.

[0065] This invention also provides an electronic device, which includes a processor and a memory; the memory stores a program; the processor executes the program to perform the aforementioned anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses; the electronic device has the function of carrying and running the business data processing software system provided in this invention, such as a personal computer (PC), mobile phone, smartphone, personal digital assistant (PDA), wearable device, handheld PC (PPC), tablet computer, vehicle terminal, etc.

[0066] This invention also provides a computer-readable storage medium storing a program that is executed by a processor to implement the aforementioned anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses.

[0067] This invention also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform the aforementioned anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses.

[0068] In embodiments of the present invention, based on an established intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform model, intra-pulse and inter-pulse sub-pulses are coded with orthogonal frequency modulation to obtain compressed sub-pulses. Using a multi-level Otsu algorithm, the inter-class variance of the compressed sub-pulses is obtained, and an optimal threshold is determined based on this inter-class variance. The difference between the target signal and three types of intermittent sampling interference signals is then determined based on the optimal threshold. These embodiments of the present invention can improve the information entropy of the transmitted waveform and effectively and meticulously distinguish the target signal and the three types of intermittent sampling forwarding interference signals. Attached Figure Description

[0069] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 A schematic diagram of intrapulse and interpulse random orthogonal frequency modulation waveforms;

[0071] Figure 2 The flowchart of Otsu's multi-stage full-pulse algorithm is shown below;

[0072] Figure 3 A schematic diagram of Otsu's algorithm for multi-stage sub-pulses;

[0073] Figure 4 The result of Otsu's algorithm for full-pulse multi-stage recognition when JSR=10dB;

[0074] Figure 5 The result of Otsu's algorithm for identifying subpulse multi-levels when JSR = 10dB;

[0075] Figure 6 The result of Otsu's algorithm for full-pulse multi-stage recognition when JSR = 20dB;

[0076] Figure 7 The result of Otsu's algorithm for identifying subpulse multi-levels when JSR = 20dB. Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0078] Intermittent sampling-forward (ISBN) jamming exhibits diverse patterns. By adjusting the modulation method and parameters, ISBN jamming can create highly realistic, controllable, and configurable active false targets. Traditional coherent pulse radars suffer from low waveform parameter freedom and poor low interception capability. When countering ISBN jamming, the design of anti-jamming signals lacks freedom, resulting in poor effectiveness and, in severe cases, even radar inoperability. Most existing ISBN jamming countermeasures differentiate between the target signal and the ISBN jamming signal, but fail to differentiate between different types of ISBN jamming.

[0079] To address the problems existing in the prior art, this invention provides a method for resisting intermittent sampling interference based on the Otsu method of random orthogonal subpulses, comprising:

[0080] S1. Establish a random coded orthogonal frequency modulation waveform model for intra-pulse and inter-pulse pulses, and perform coded orthogonal frequency modulation on intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses.

[0081] Specifically, the purposes of modulation include: facilitating wireless transmission and reducing antenna size, increasing communication capacity through frequency division multiplexing, and improving signal anti-interference capability. The intra-pulse modulation waveform of radar is generally designed according to the needs of pulse compression technology. Currently, the commonly used modulation methods are frequency modulation, amplitude modulation, and phase modulation. Among them, the commonly used frequency modulation methods include: linear frequency modulation, nonlinear frequency modulation, frequency coding, and frequency step frequency modulation.

[0082] The intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform model is as follows:

[0083]

[0084] in,

[0085] In the formula, S(t) represents the intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform, N represents the number of pulses transmitted by the radar, P represents the number of sub-pulses within each pulse, S(t,n,m) represents the expression for the m-th sub-pulse within the n-th pulse, a(t) can be linear frequency modulation, nonlinear frequency modulation, pulse, phase-coded signals, etc., δ represents the impulse function, t represents the time variable, and τ sub T represents the sub-pulse width. s Represents the repetition period, e represents the exponential function, j represents the imaginary unit, and f represents the repetition period. m The initial carrier frequency represents the subpulse.

[0086] S2. Based on the multi-level Otsu algorithm, obtain the inter-class variance of the compressed sub-pulse, and obtain the optimal threshold based on the inter-class variance of the compressed sub-pulse.

[0087] Specifically, Otsu's algorithm is an algorithm for determining the threshold for image binarization segmentation. Because the inter-class variance between the foreground and background images is maximized after image binarization segmentation using the threshold obtained by Otsu's algorithm, this method is also known as the maximum inter-class variance algorithm. Otsu's algorithm is simple to calculate and is not affected by image brightness and contrast. This method divides the image into two parts, background and foreground, according to the grayscale characteristics of the image. The larger the inter-class variance between the background and foreground, the greater the difference between the two parts constituting the image. Therefore, segmentation that maximizes the inter-class variance means minimizing the probability of misclassification.

[0088] S3. Determine the difference between the target signal and the three intermittent sampling interference signals based on the optimal threshold;

[0089] Specifically, typical intermittent sampling forwarding interference currently includes three types: intermittent sampling direct forwarding interference, intermittent sampling repeated forwarding interference, and intermittent sampling cyclic forwarding interference.

[0090] Optionally, in some embodiments, step S2 specifically includes the following steps:

[0091] S21. Obtain the absolute value of the time-domain variance of the sub-pulse compression corresponding to each echo signal, and arrange the absolute values ​​into a target array;

[0092] Specifically, the absolute values ​​of the time-domain variances of the sub-pulses corresponding to each echo signal after compression are obtained. These absolute values ​​include: the absolute value of the time-domain variance of the target signal, the absolute value of the time-domain variance of the directly sampled and forwarded interference signal, the absolute value of the time-domain variance of the repeatedly sampled and forwarded interference signal, and the absolute value of the time-domain variance of the cyclically sampled and forwarded interference signal. The absolute values ​​are arranged in ascending order to form a target array. The target array can be a one-dimensional array with a size of 4NP, where N represents the number of radar pulses and P represents the number of sub-pulses within each pulse.

[0093] S22. Obtain the threshold based on the target array;

[0094] Specifically, the threshold is an adaptive threshold that varies depending on the environment, target, and type of intermittent sampling forwarding interference.

[0095] S23. Iterate through all thresholds to obtain the optimal threshold.

[0096] Optionally, in some embodiments, step S22 specifically includes the following steps:

[0097] S221. Select the first data according to the target array to obtain the first-level threshold and form the first sub-interval;

[0098] S222: Select the second data according to the target array to obtain the second-level threshold and form the second sub-interval;

[0099] S223. Select the third data according to the target array to obtain the third-level threshold and form the third sub-interval;

[0100] S224. Based on the data of the target array, the first sub-interval, the second sub-interval, and the third sub-interval, form a fourth sub-interval;

[0101] Specifically, the first data is less than the second data, the second data is less than the third data, and the third data is less than the size of the target array; the first data serves as a first-level threshold, and a first sub-interval is formed based on the first-level threshold; the second data serves as a second-level threshold, and a second sub-interval is formed based on the second-level threshold; the third data serves as a third-level threshold, and a third sub-interval is formed based on the third-level threshold; a fourth sub-interval is formed based on the data of the target array, the first sub-interval, the second sub-interval, and the third sub-interval.

[0102] Optionally, in some embodiments, step S23 specifically includes the following steps:

[0103] S231. Calculate the probability of the occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval;

[0104] Specifically, the formula for calculating the probability of the first sub-interval occurring is as follows:

[0105]

[0106] The formula for calculating the probability of the second sub-interval occurring is:

[0107]

[0108] The formula for calculating the probability of the third sub-interval occurring is:

[0109]

[0110] The formula for calculating the probability of the fourth sub-interval occurring is:

[0111]

[0112] In the formula, w1 represents the probability of the first sub-interval occurring, w2 represents the probability of the second sub-interval occurring, w3 represents the probability of the third sub-interval occurring, w4 represents the probability of the fourth sub-interval occurring, i represents the first data, j represents the second data, k represents the third data, 4NP represents the size of the target array, where N represents the number of pulses emitted by the radar, and P represents the number of sub-pulses within each pulse;

[0113] S232. Calculate the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval;

[0114] Specifically, the formula for calculating the average amplitude of the first sub-interval is as follows:

[0115]

[0116] The formula for calculating the average amplitude of the second sub-interval is:

[0117]

[0118] The formula for calculating the average amplitude of the third sub-interval is as follows:

[0119]

[0120] The formula for calculating the average amplitude of the fourth sub-interval is as follows:

[0121]

[0122] The formula for calculating the average amplitude of the total interval is:

[0123]

[0124] In the formula, λ1 represents the average amplitude of the first sub-interval, λ2 represents the average amplitude of the second sub-interval, λ3 represents the average amplitude of the third sub-interval, λ4 represents the average amplitude of the fourth sub-interval, λ represents the average amplitude of the total interval, and Var represents the target array.

[0125] S233. Define the inter-class variance based on the probability of occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval, as well as the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval.

[0126] Specifically, the formula for the inter-class variance is:

[0127]

[0128] In the formula, σ 2 w represents the inter-class variance. h λ represents the probability of a subinterval occurring. h λ represents the average amplitude of the sub-interval, and λ represents the average amplitude of the total interval.

[0129] S234. Iterate through all thresholds until the maximum inter-class variance is obtained, thus obtaining the optimal threshold.

[0130] Specifically, the optimal threshold expression is:

[0131]

[0132] In the formula, T1 * T2 * T3 * T1 represents the first-level threshold, T2 represents the second-level threshold, and T3 represents the third-level threshold.

[0133] The implementation process of an anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses according to an embodiment of the present invention is described as follows:

[0134] Step 1: Based on the pulse transmitted by the radar, randomly select the carrier frequency of the sub-pulse within the frequency band of the total frequency bandwidth to obtain the corresponding sub-pulse within each pulse. The number of frequency bands within the total frequency bandwidth is... B represents rounding down, B represents the operating frequency bandwidth, Δf represents the hopping frequency value of adjacent frequency bands, and the carrier frequency difference of the corresponding sub-pulse within each pulse is an integer multiple of the hopping frequency value of the adjacent frequency band.

[0135] Step 2: Combining the corresponding sub-pulses within each pulse, establish intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform models. Perform orthogonal frequency modulation on the intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses. The intra-pulse and inter-pulse random coded orthogonal frequency modulation waveforms are as follows: Figure 1 As shown, four sub-pulses form one pulse. The four small rectangles represent four sub-pulses, and the larger rectangle formed by the four small rectangles constitutes one pulse. These pulses together form an inter-pulse. Figure 1 In the diagram, f1 to f4 represent the sub-frequency of the four sub-pulses, τ sub T represents the sub-pulse width, τ represents the pulse width of the pulse, and T represents the pulse width of the pulse. s Represents the repetition period;

[0136] Step 3: Based on the multi-level Otsu algorithm, obtain the inter-class variance of the compressed sub-pulses. Obtain the optimal threshold based on the inter-class variance of the compressed sub-pulses. The threshold determination is performed using all sub-pulses as follows: Figure 2 As shown:

[0137] Obtain the absolute value of the time-domain variance of the sub-pulse after compression for each echo signal, and arrange the absolute values ​​into a target array;

[0138] A threshold is selected based on the target array to form a corresponding sub-interval;

[0139] Calculate the occurrence probability of the corresponding sub-interval, calculate the average amplitude of the corresponding sub-interval and the total interval, and obtain the inter-class variance based on the occurrence probability and the average amplitude;

[0140] Iterate through all thresholds until the maximum inter-class variance is obtained, thus obtaining the optimal threshold.

[0141] Step 4: Set differentiated thresholds for each sub-pulse, such as... Figure 3 As shown, the radar echo signal is sampled and demodulated, and the Otsu algorithm with multiple levels is used for each sub-pulse to obtain the optimal threshold corresponding to each sub-pulse under the inter-class variance maximization criterion.

[0142] Finally, by obtaining the optimal threshold based on the above steps, the difference between the target signal and the three intermittent sampling interference signals is determined.

[0143] Taking the anti-interference simulation experiment as an example, the simulation analysis of the Otsu algorithm for full-pulse multi-level and sub-pulse multi-level is used to analyze the recognition accuracy of target signals and three types of interference. The random orthogonal frequency modulation waveform parameters are shown in Table 1. The radar operates in the S-band with a carrier frequency of 3 GHz, a transmit pulse width of 41 μs, a pulse repetition period of 1 ms, and transmits a total of 10 pulses. Each pulse contains 8 sub-pulses with a sub-pulse bandwidth of 10 MHz. The total bandwidth of the operating frequency is 400 MHz. The frequency interval between each jump is 20 MHz, the jump frequency value of adjacent frequency bands is 40 MHz, the interference pulse width is 1 μs, the interference delay is 0.2 μs, and the interference repetition period is 10.2 μs.

[0144] Table 1

[0145] parameter numerical values parameter numerical values <![CDATA[T p ]]> 41μs B 400MHz <![CDATA[τ J ]]> 1μs <![CDATA[B sub ]]> 10MHz <![CDATA[τ d ]]> 0.2μs Δf 40MHz <![CDATA[T J ]]> 10.2μs P 8

[0146] Set the first interference signal ratio (JSR), the second interference signal ratio (JSR), and the signal-to-noise ratio (SNR) of the subpulse after pulse compression, and perform 300 Monte Carlo simulations. The first interference signal ratio (JSR) is JSR = 10dB, the second interference signal ratio (JSR) is JSR = 20dB, and the signal-to-noise ratio (SNR) of the subpulse after matched filtering is SNR = -20dB to 20dB.

[0147] Under the condition of the first interference-to-signal ratio, the recognition result of the Otsu algorithm for full-pulse multi-stage is as follows: Figure 4 As shown, with the increase of the subpulse signal-to-noise ratio after pulse compression, the recognition accuracy of the target signal, the intermittent sampling direct forwarding interference signal, and the intermittent sampling cyclic forwarding interference signal all show an upward trend. When the signal-to-noise ratio SNR = 0dB, the confusion matrix of the Otsu algorithm for the full pulse multi-level is shown in Table 2. 40 intermittently sampled and repeatedly forwarded interference signals are identified as intermittently sampled cyclic forwarding interference signals.

[0148] Therefore, this invention further distinguishes between intermittent sampling repeated forwarding interference signals and intermittent sampling cyclic forwarding interference signals by setting an adaptive sub-pulse threshold, such as... Figure 5 As shown, with the improvement of signal-to-noise ratio, the recognition accuracy of target signal, intermittent sampling direct forwarding interference signal, intermittent sampling cyclic forwarding interference signal and intermittent sampling repeated forwarding interference signal is improved. The Otsu algorithm confusion matrix of sub-pulse multi-level is shown in Table 3. By setting the sub-pulse adaptive threshold, the intermittent sampling repeated forwarding interference signal and the intermittent sampling cyclic forwarding interference signal can be accurately distinguished. The signal modes corresponding to the full-pulse multi-level Otsu algorithm confusion matrix and the sub-pulse multi-level Otsu algorithm confusion matrix are shown in Table 4: Mode 1 represents the target signal, Mode 2 represents the target signal and the intermittent sampling direct forwarding interference signal, Mode 3 represents the target signal and the intermittent sampling repeated forwarding interference signal, and Mode 4 represents the target signal and the intermittent sampling cyclic forwarding interference signal.

[0149] Table 2

[0150] Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 78 1 1 0 Mode 2 4 70 3 3 Mode 3 2 3 35 40 Mode 4 4 3 0 73

[0151] Table 3

[0152] Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 75 2 2 1 Mode 2 4 74 0 2 Mode 3 2 3 71 4 Mode 4 4 3 0 73

[0153] Table 4

[0154] Mode 1 Target signal Mode 2 Target signal + direct relay jamming Mode 3 Target signal + repeated relay interference Mode 4 Target signal + loop relay interference

[0155] Under the condition of a second interference-to-signal ratio, the recognition results of the Otsu algorithm for full-pulse multi-stage recognition are as follows: Figure 6 As shown, the recognition results of the Otsu algorithm for multi-level sub-pulses are as follows: Figure 7 As shown, under low signal-to-noise ratio conditions, the recognition accuracy of the target signal, intermittent sampling direct forwarding interference signal, intermittent sampling cyclic forwarding interference signal, and intermittent sampling repeated forwarding interference signal is stable.

[0156] The present invention also provides an anti-intermittent sampling interference device based on the Otsu method of random orthogonal subpulses, comprising:

[0157] The first module is used to establish intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform models, and to encode and orthogonally frequency modulate intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses.

[0158] The second module is used to obtain the inter-class variance of the compressed sub-pulse based on the multi-level Otsu algorithm, and to obtain the optimal threshold based on the inter-class variance of the compressed sub-pulse.

[0159] The third module is used to determine the difference between the target signal and the three intermittent sampling interference signals based on the optimal threshold.

[0160] Optionally, in some embodiments, the second module specifically includes the following sub-modules:

[0161] The first submodule is used to obtain the absolute value of the time-domain variance of the subpulse compression corresponding to each echo signal, and arrange the absolute values ​​into a target array;

[0162] The second submodule is used to obtain the threshold based on the target array;

[0163] The third submodule is used to iterate through all thresholds to obtain the optimal threshold.

[0164] Optionally, in some embodiments, the third submodule specifically includes the following units:

[0165] The first unit is used to calculate the probability of the occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval;

[0166] The second unit is used to calculate the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval;

[0167] The third unit is used to define the inter-class variance based on the probability of occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval, as well as the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval.

[0168] The fourth unit is used to iterate through all thresholds until the maximum inter-class variance is obtained, thus yielding the optimal threshold.

[0169] This invention also provides an electronic device, which includes a processor and a memory; the memory stores a program; the processor executes the program to perform the aforementioned anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses; the electronic device has the function of carrying and running the business data processing software system provided in this invention, such as a personal computer (PC), mobile phone, smartphone, personal digital assistant (PDA), wearable device, handheld PC (PPC), tablet computer, vehicle terminal, etc.

[0170] This invention also provides a computer-readable storage medium storing a program that is executed by a processor to implement the aforementioned anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses.

[0171] This invention also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform the aforementioned anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses.

[0172] In summary, the anti-intermittent sampling interference method based on the Otsu method of random orthogonal subpulses according to embodiments of the present invention has the following advantages:

[0173] 1. This invention uses intra-pulse and inter-pulse random orthogonal frequency modulation waveforms, which can improve the information entropy of the transmitted waveform. This is equivalent to constructing a higher-dimensional function space on the transmitted signal than that of the conventional signal. From the perspective of the signal function space, the interference signal is underdimensional. The differences in the feature dimensions can be used to authenticate each echo signal, thereby realizing the identification and differentiation of the interference signal.

[0174] 2. The Otsu algorithm for full-pulse multi-level and sub-pulse multi-level proposed in this invention uses the inter-class variance of sub-pulses after pulse compression, which can differentiate the variances of the three intermittent sampling and forwarding interference signals, thereby improving the accuracy of identification and differentiation of the three intermittent sampling and forwarding interference signals.

[0175] 3. The present invention sets an adaptive sub-pulse threshold that can change according to the changes in the environment, target signal, and type of intermittent sampling and forwarding interference signal, which can further improve the distinction between intermittent sampling and repeated forwarding interference signals and intermittent sampling and cyclic forwarding interference signals.

[0176] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.

[0177] Furthermore, although the invention has been described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the described functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the invention. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional skill of an engineer. Therefore, those skilled in the art can implement the invention as set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of the invention, which is determined by the full scope of the appended claims and their equivalents.

[0178] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0179] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0180] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0181] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0182] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0183] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0184] The above is a detailed description of the preferred embodiments of the present invention, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for resisting intermittent sampling interference based on Otsu's method for random orthogonal subpulses, characterized in that, include: Establish a random coded orthogonal frequency modulation waveform model for intra-pulse and inter-pulse sub-pulses, and perform coded orthogonal frequency modulation on intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses; Based on the multi-level Otsu algorithm, the inter-class variance of the compressed sub-pulse is obtained, and the optimal threshold is obtained based on the inter-class variance of the compressed sub-pulse. The difference between the target signal and the three intermittent sampling interference signals is determined based on the optimal threshold.

2. The method for resisting intermittent sampling interference based on Otsu's method of random orthogonal subpulses according to claim 1, characterized in that, The intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform model is as follows: ； In the formula, This represents the intra-pulse and inter-pulse randomly encoded orthogonal frequency modulated waveforms. Represents the number of pulses emitted by the radar. This represents the number of sub-pulses within each pulse. Representing the The first pulse within the [number] pulses The expression for each sub-pulse.

3. The method for resisting intermittent sampling interference based on Otsu's method of random orthogonal subpulses according to claim 1, characterized in that, The step of obtaining the inter-class variance of the compressed sub-pulses based on the multi-level Otsu algorithm, and obtaining the optimal threshold based on the inter-class variance of the compressed sub-pulses, includes: Obtain the absolute value of the time-domain variance of the sub-pulse after compression for each echo signal, and arrange the absolute values ​​into a target array; The threshold is obtained based on the target array; Iterate through all thresholds to find the optimal threshold.

4. The method for resisting intermittent sampling interference based on Otsu's method of random orthogonal subpulses according to claim 3, characterized in that, The step of obtaining the threshold based on the target array includes: The first data point is selected from the target array to obtain the first-level threshold, thus forming the first sub-interval. Based on the target array, a second data point is selected to obtain the second-level threshold, forming the second sub-interval; Based on the target array, a third data point is selected to obtain the third-level threshold, forming the third sub-interval; A fourth sub-interval is formed based on the data of the target array, the first sub-interval, the second sub-interval, and the third sub-interval.

5. The method for resisting intermittent sampling interference based on Otsu's method of random orthogonal subpulses according to claim 4, characterized in that, The loop iterates through all thresholds to obtain the optimal threshold, including: Calculate the probability of the occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval; Calculate the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval; The inter-class variance is defined based on the probability of occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval, as well as the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval. Iterate through all thresholds until the maximum inter-class variance is obtained, thus obtaining the optimal threshold. The formula for calculating the probability of the first sub-interval occurring is: ； The formula for calculating the probability of the second sub-interval occurring is: ； The formula for calculating the probability of the third sub-interval occurring is: ； The formula for calculating the probability of the fourth sub-interval occurring is: ； In the formula, This represents the probability of the first sub-interval occurring. This represents the probability of the second subinterval occurring. This represents the probability of the third sub-interval occurring. This represents the probability of the fourth sub-interval occurring. Represents the first data point. Representing the second data, Representing the third data, Represents the size of the target array, where, Represents the number of pulses emitted by the radar. This represents the number of sub-pulses within each pulse; The formula for calculating the average amplitude of the first sub-interval is: ； The formula for calculating the average amplitude of the second sub-interval is: ； The formula for calculating the average amplitude of the third sub-interval is as follows: ； The formula for calculating the average amplitude of the fourth sub-interval is as follows: ； The formula for calculating the average amplitude of the total interval is: ； In the formula, This represents the average amplitude of the first sub-interval. This represents the average amplitude of the second sub-interval. This represents the average amplitude of the third sub-interval. This represents the average amplitude of the fourth sub-interval. This represents the average amplitude of the total interval. Represents the target array; The formula for the inter-class variance is: ； In the formula, Represents the variance between classes. Represents the probability of occurrence in a subinterval. The average amplitude of the sub-interval, This represents the average amplitude of the total interval; The optimal threshold expression is: ； In the formula, Represents the optimal threshold. This represents the first-level threshold. This represents the second-level threshold. This represents the third-level threshold.

6. A device for resisting intermittent sampling interference based on the Otsu method of random orthogonal subpulses, characterized in that, include: The first module is used to establish intra-pulse and inter-pulse random coded orthogonal frequency modulation waveform models, and to encode and orthogonally frequency modulate intra-pulse and inter-pulse sub-pulses to obtain pulse-compressed sub-pulses. The second module is used to obtain the inter-class variance of the compressed sub-pulse based on the multi-level Otsu algorithm, and to obtain the optimal threshold based on the inter-class variance of the compressed sub-pulse. The third module is used to determine the difference between the target signal and the three intermittent sampling interference signals based on the optimal threshold.

7. The anti-intermittent sampling interference device based on the Otsu method of random orthogonal subpulses according to claim 6, characterized in that, The second module is used to obtain the inter-class variance of the compressed sub-pulses according to the multi-level Otsu algorithm, and to obtain the optimal threshold based on the inter-class variance of the compressed sub-pulses, including: The first submodule is used to obtain the absolute value of the time-domain variance of the subpulse compression corresponding to each echo signal, and arrange the absolute values ​​into a target array; The second submodule is used to obtain the threshold based on the target array; The third submodule is used to iterate through all thresholds to obtain the optimal threshold. The second submodule is specifically used for: The first data point is selected from the target array to obtain the first-level threshold, thus forming the first sub-interval. Based on the target array, a second data point is selected to obtain the second-level threshold, forming the second sub-interval; Based on the target array, a third data point is selected to obtain the third-level threshold, forming the third sub-interval; A fourth sub-interval is formed based on the data of the target array, the first sub-interval, the second sub-interval, and the third sub-interval.

8. The anti-intermittent sampling interference device based on the Otsu method of random orthogonal subpulses according to claim 7, characterized in that, The third submodule is used to iterate through all thresholds to obtain the optimal threshold, including: The first unit is used to calculate the probability of the occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval; The second unit is used to calculate the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval; The third unit is used to define the inter-class variance based on the probability of occurrence of the first sub-interval, the second sub-interval, the third sub-interval, and the fourth sub-interval, as well as the average amplitude of the first sub-interval, the second sub-interval, the third sub-interval, the fourth sub-interval, and the total interval. The fourth unit is used to iterate through all thresholds until the maximum inter-class variance is obtained, thus yielding the optimal threshold.

9. An electronic device, characterized in that, Including the processor and memory; The memory is used to store programs; The processor executes the program to implement the method as described in any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that, The storage medium stores a program that is executed by a processor to implement the method as described in any one of claims 1 to 5.

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