Intermittent chaos detection frequency left and right fuzzy elimination method

Abstract

The invention relates to the field of weak characteristic signal detection, and provides an intermittent chaos detection frequency left and right fuzzy elimination method. A multi-interval Duffing oscillator system is constructed and formed, a fourth-order Runge-Kutta numerical solution is used for solving the multi-interval Duffing oscillator system to generate multi-interval Duffing chaotic oscillator frequency response, feature information fusion is carried out on multi-interval Duffing chaotic oscillators, and target false alarm feature frequency is eliminated through identity judgment of multi-oscillator output signal features. And left and right fuzzy elimination of weak target characteristic signals is realized. According to the method, the problem that the real frequency characteristics of the target are'left and right fuzzy 'when the real frequency of the target is solved by the frequency value of the intermittent chaos envelope is solved, and effective identification and fusion enhancement of weak target characteristics are realized.

Description

Technical Field

[0001] The invention relates to the field of weak characteristic signal detection, and mainly relates to a method for eliminating left and right fuzziness of intermittent chaotic detection frequency. Background Art

[0002] Due to the inhomogeneity of the water medium and the unevenness of the interface, as well as the changes in the spectral structure of the radiation noise caused by the changes in the working conditions of the target platform and the influence of the Doppler frequency deviation caused by the platform maneuvering, the received underwater acoustic signal is an undulating signal with frequency deviation characteristics. The conventional Duffing chaotic system is sensitive to the initial value and frequency deviation parameters, and it is difficult to use a set of chaotic systems with specific parameters for long-term detection. The intermittent Duffing chaotic system uses the intermittent chaotic characteristics excited by the frequency difference between the signal to be measured and the driving force signal for detection. It has tolerance to the line spectrum frequency deviation characteristics and is more suitable for the application of weak underwater acoustic signal detection.

[0003] In the existing research results, the following problems exist in the signal detection method of the Duffing chaotic system. The frequency value of the intermittent chaotic envelope detection is the absolute value of the difference between the driving force frequency and the true frequency. When the target true frequency is solved by the frequency value of the intermittent chaotic envelope, there will be two results: the driving force frequency + the intermittent chaotic envelope frequency value and the driving force frequency - the intermittent chaotic envelope frequency value, that is, there is a problem of "left and right ambiguity" in the target true frequency characteristics.

[0004] To solve the above problems, a multi-intermittent Duffing chaotic feature fusion system is constructed. By fusing the multi-oscillator features, the “left-right fuzziness” effect of intermittent Duffing chaotic detection on the target’s real frequency characteristics is eliminated, and effective identification and fusion enhancement of weak target features are achieved. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for eliminating left and right ambiguity of intermittent chaotic detection frequency.

[0006] The object of the present invention is achieved through the following technical solution: A method for eliminating left and right ambiguity of intermittent chaotic detection frequency, comprising the following steps:

[0007] Step 1: Construction of a multi-intermittent Duffing oscillator system to eliminate the left and right ambiguity of intermittent chaotic detection frequency: Set the system driving force frequency sequence, construct a multi-intermittent Duffing oscillator system, and eliminate the target false alarm characteristic frequency through the identity judgment of the multi-oscillator output signal characteristics, so as to achieve accurate detection of the input signal to be tested;

[0008] Step 2: Numerical solution of multi-intermittent Duffing oscillator system: Based on the given starting time and initial value of the Duffing oscillator system, the multi-intermittent Duffing oscillator system is solved using the fourth-order Runge-Kutta numerical solution method with a certain time step; the solution result is Fourier transformed to generate the output frequency domain response of the multi-intermittent Duffing chaotic oscillator array;

[0009] Step 3: Feature fusion of multiple intermittent Duffing chaotic oscillators: Using the weighted average fusion criterion, set the inverse of the system driving force characteristic amplitude as the weighted value to suppress false alarm interference and enhance the detection of weak characteristic signals; fuse the feature information of multiple intermittent Duffing chaotic oscillators to eliminate the "left and right ambiguity" of target features and enhance the fusion of weak target features.

[0010] Furthermore, in the step 1, a multi-intermittent Duffing oscillator system is constructed, and the target false alarm characteristic frequency is eliminated by distinguishing the identity of the output signal characteristics of the multi-oscillators, so as to achieve accurate detection of the input signal to be tested; the multi-intermittent Duffing oscillator system is as follows:

[0011]

[0012] Among them, Acos(ω i t+θ) is the driving force of the system, ω i is the system driving frequency, θ is the system driving phase, i=1,2,…2N+1, is the Duffing oscillator number, there are 2N+1 detection arrays, and the driving frequency of each oscillator is set to Where dω is the frequency deviation increment between oscillators; in order to achieve stable intermittent chaotic results and resolvable frequency, the frequency difference range of intermittent Duffing chaotic oscillators must satisfy |ω i -ω xj / ω i |≤0.03,j=1,2,……,a xj cos(ω xj t) is the target signal to be measured containing multiple frequency points, and n(t) is the background noise.

[0013] Furthermore, in step 2, given the starting time t0 and the initial value of the Duffing oscillator system yi(0)=[x0′,x0″], with h as the time step, the result of the multi-intermittent Duffing oscillator system is solved by an iterative method based on the fourth-order Runge-Kutta numerical solution. The fourth-order Runge-Kutta numerical solution at the tnth time is as follows:

[0014] yi(n+1)=yi(n)+h / 6(k1+2*k2+2*k3+k4)

[0015] k1=fi(tn,yi(n))

[0016] k2=fi(tn+h / 2,yi(n)+h*k1 / 2)

[0017] k3=fi(tn+h / 2,yi(n)+h*k2 / 2)

[0018] k4=fi(tn+h,yi(n)+h*k3)

[0019] Among them, fi(t,y) is the equation of each Duffing oscillator in the multi-intermittent Duffing chaotic oscillator system. The above solution results are subjected to Fourier transform, and Yi(ω)=FFT(yi(t)), Yi(ω) is the output frequency domain response of the i-th intermittent Duffing chaotic oscillator array.

[0020] Furthermore, in the step 3, a weighted average fusion criterion is adopted, and the inverse of the characteristic amplitude of the system driving force is set as the weighted value to fuse the characteristic information of multiple intermittent Duffing chaotic oscillators, specifically:

[0021]

[0022] Where Yi(ω) is the output response of the i-th intermittent Duffing chaotic oscillator array, α i is the fusion weight value, 2N+1 is the number of oscillators in the array, α i is the weighted coefficient of weighted average fusion, and Y(ω) is the fusion result of multiple intermittent Duffing chaotic oscillator characteristics.

[0023] The beneficial effects of the present invention are as follows: the present invention provides a method for eliminating the left and right ambiguity of intermittent chaotic detection frequency. A multi-intermittent Duffing oscillator system is constructed, and the fourth-order Runge-Kutta numerical solution is used to solve it to generate the frequency response of the multi-intermittent Duffing chaotic oscillator. The characteristic information of the multi-intermittent Duffing chaotic oscillators is fused, and the identity of the output signal characteristics of the multi-oscillator is judged to eliminate the target false alarm characteristic frequency, so as to achieve the elimination of the "left and right ambiguity" of the weak target characteristic signal. The problem of "left and right ambiguity" of the target real frequency characteristics when the frequency value of the intermittent chaotic envelope is used to solve the target real frequency is solved, and the effective identification and fusion enhancement of the weak target characteristics are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art or ordinary technicians, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is an implementation block diagram of the present invention.

[0026] Figure 2 It is the time domain waveform and phase diagram of the output signals of the four oscillators in the multi-intermittent Duffing chaotic system.

[0027] Figure 3 This paper compares and analyzes the frequency domain characteristics of the output signals of the four oscillators in a multi-intermittent Duffing chaotic system.

[0028] Figure 4 It is the target feature fusion result of multi-intermittent Duffing chaotic system. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0030] See also Figure 1 The embodiment of the present invention provides a method for eliminating left and right ambiguity of intermittent chaotic detection frequency, comprising the following modules:

[0031] Building blocks of a multi-intermittent Duffing oscillator system to eliminate the left and right ambiguity of intermittent chaotic detection frequency:

[0032] In order to detect the "left-right ambiguity problem" of the intermittent Duffing chaotic system, an intermittent Duffing oscillator array is constructed. By distinguishing the identity of the output signal characteristics of multiple oscillators, the target false alarm characteristic frequency is eliminated. The frequency point value of the stable output of the multi-intermittent Duffing oscillator is the frequency of the signal to be tested, and the input signal frequency to be tested is accurately detected. The multi-intermittent Duffing chaotic oscillator system is as follows:

[0033]

[0034] In the above formula, Acos(ω i t+θ) is the driving force of the system, ω i is the system driving frequency, θ is the system driving phase, i=1,2,…2N+1, is the Duffing oscillator number, there are 2N+1 detection arrays, and the driving frequency of each oscillator is set to Where dω is the frequency deviation increment between oscillators. In order to achieve stable intermittent chaotic results and distinguishable frequencies, the frequency difference range of intermittent Duffing chaotic oscillators must satisfy |ω i -ωxj / ω i |≤0.03,j=1,2,……,a xj cos(ω xj t) is the target signal to be measured containing multiple frequency points, and n(t) is the background noise.

[0035] Numerical solution module for multi-intermittent Duffing oscillator system:

[0036] The multi-intermittent Duffing oscillator system is solved by the fourth-order Runge-Kutta numerical solution. Given the starting time t0 and the initial value of the Duffing oscillator system yi(0) = [x0′, x0″], with h as the time step, the system results are solved by the iterative method based on the fourth-order Runge-Kutta numerical solution. The fourth-order Runge-Kutta numerical solution at the tnth time is as follows:

[0037] yi(n+1)=yi(n)+h / 6(k1+2*k2+2*k3+k4)

[0038] k1=fi(tn,yi(n))

[0039] k2=fi(tn+h / 2,yi(n)+h*k1 / 2)

[0040] k3=fi(tn+h / 2,yi(n)+h*k2 / 2)

[0041] k4=fi(tn+h,yi(n)+h*k3)

[0042] Among them, fi(t,y) is the equation of each Duffing oscillator in the multi-intermittent Duffing chaotic oscillator system. The above solution is Fourier transformed, and Yi(ω)=FFT(yi(t)), which is the output frequency domain response of the i-th intermittent Duffing chaotic oscillator array.

[0043] Multi-intermittent Duffing chaotic oscillator feature fusion module:

[0044] The characteristic information of multiple intermittent Duffing chaotic oscillators is fused to eliminate the "left and right fuzziness" of target characteristics and enhance the fusion of weak target characteristics. The weighted average fusion criterion is adopted, and the weighted value is the inverse of the characteristic amplitude of the system driving force. It has good tolerance to input data and can suppress false alarm interference, so as to achieve better enhancement of weak characteristics.

[0045]

[0046] Where Yi(ω) is the output response of the i-th intermittent Duffing chaotic oscillator array, α i is the fusion weight value, 2N+1 is the number of oscillators in the array, αi is the weighted coefficient of weighted average fusion, and Y(ω) is the fusion result of multiple intermittent Duffing chaotic oscillator characteristics.

[0047] The following is a performance design example of the present invention:

[0048] Simulation scenario: For a set of platform radiation noise data, based on the constructed multi-intermittent Duffing chaos feature fusion system, the target feature information analysis and verification are carried out. The first is the time domain characteristics analysis of the output signal of the multi-intermittent Duffing chaos system. By analyzing the output response time domain waveform and phase diagram of the multi-intermittent Duffing chaos oscillator system, it shows a strong intermittent chaos characteristic. The time domain waveform and phase diagram of the output signal of the four oscillators of the multi-intermittent Duffing chaos system are shown in Figure 1. Figure 2 As shown, Figure 2 (a) is the time domain waveform of the output of oscillator 1, Figure 2 (b) is the output phase diagram of oscillator 1; Figure 2 (c) is the time domain waveform output by oscillator 2, Figure 2 (d) is the output phase diagram of oscillator 2; Figure 2 (e) is the time domain waveform output by oscillator 3, Figure 2 (f) is the output phase diagram of oscillator 3; Figure 2 (g) is the time domain waveform output by the oscillator 4, Figure 2 (h) is the output phase diagram of oscillator 4. The second is the frequency domain characteristics analysis of the output signal of the multi-intermittent Duffing chaotic system. Figure 3 As shown in the figure, the frequency domain target features of the multi-intermittent Duffing chaotic oscillator array are compared and analyzed. The multi-intermittent Duffing chaotic oscillator system has the problem of false alarm of "left-right ambiguity" of spectrum features. The third is the feature fusion processing of the output signal of the multi-intermittent Duffing chaotic system. The output response of each intermittent Duffing chaotic oscillator is incoherent, and it has the conditions for incoherent fusion processing in the frequency domain. The feature fusion processing of the oscillator output signal of the multi-intermittent Duffing chaotic system is carried out to eliminate the "left-right ambiguity" of the target features and enhance the fusion of weak target features. The target feature fusion results of the multi-intermittent Duffing chaotic oscillator are shown in the figure. Figure 4 shown.

[0049] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for eliminating left and right ambiguity in intermittent chaotic detection frequency, characterized in that: The steps include: Step 1: Construction of a multi-intermittent Duffing oscillator system to eliminate the left and right ambiguity of intermittent chaotic detection frequency: Set the system driving force frequency sequence, construct a multi-intermittent Duffing oscillator system, and eliminate the target false alarm characteristic frequency through the identity judgment of the multi-oscillator output signal characteristics, so as to achieve accurate detection of the input signal to be tested; Step 2: Numerical solution of multi-intermittent Duffing oscillator system: Based on the given starting time and initial value of the Duffing oscillator system, the multi-intermittent Duffing oscillator system is solved using the fourth-order Runge-Kutta numerical solution method with a certain time step; the solution result is Fourier transformed to generate the output frequency domain response of the multi-intermittent Duffing chaotic oscillator array; Step 3: Feature fusion of multiple intermittent Duffing chaotic oscillators: Using the weighted average fusion criterion, the inverse of the system driving force characteristic amplitude is set as the weighted value, and the feature information of multiple intermittent Duffing chaotic oscillators is fused to eliminate the "left and right fuzziness" of target features and enhance the fusion of weak target features.

2. The method for eliminating left and right ambiguity of intermittent chaotic detection frequency according to claim 1 is characterized in that: In the step 1, a multi-intermittent Duffing oscillator system is constructed, and the target false alarm characteristic frequency is eliminated by distinguishing the identity of the output signal characteristics of the multi-oscillators, so as to achieve accurate detection of the input signal to be measured; the multi-intermittent Duffing oscillator system is as follows: Among them, Acos(ω i t+θ) is the driving force of the system, ω i is the system driving frequency, θ is the system driving phase, i=1,2,…2N+1, is the Duffing oscillator number, there are 2N+1 detection arrays, and the driving frequency of each oscillator is set to Where dω is the frequency deviation increment between oscillators; in order to achieve stable intermittent chaotic results and resolvable frequency, the frequency difference range of intermittent Duffing chaotic oscillators must satisfy |ω i -ω xj / ω i |≤0.03,j=1,2,……,a xj cos(ω xj t) is the target signal to be measured containing multiple frequency points, and n(t) is the background noise.

3. The intermittent chaos detection frequency left and right ambiguity elimination method according to claim 2 is characterized in that: In the step 2, given the starting time t0 and the initial value of the Duffing oscillator system yi(0)=[x0′,x0″], with h as the time step, the result of the multi-intermittent Duffing oscillator system is solved by an iterative method based on the fourth-order Runge-Kutta numerical solution. The fourth-order Runge-Kutta numerical solution at the tnth time is as follows: yi(n+1)=yi(n)+h / 6(k1+2*k2+2*k3+k4) k1=fi(tn,yi(n)) k2=fi(tn+h / 2,yi(n)+h*k1 / 2) k3=fi(tn+h / 2,yi(n)+h*k2 / 2) k4=fi(tn+h,yi(n)+h*k3) Among them, fi(t,y) is the equation of each Duffing oscillator in the multi-intermittent Duffing chaotic oscillator system. The above solution results are subjected to Fourier transform, and Yi(ω)=FFT(yi(t)), Yi(ω) is the output frequency domain response of the i-th intermittent Duffing chaotic oscillator array.

4. The intermittent chaos detection frequency left and right ambiguity elimination method according to claim 1 is characterized in that: In the step 3, the weighted average fusion criterion is adopted, the inverse of the characteristic amplitude of the system driving force is set as the weighted value, and the characteristic information of multiple intermittent Duffing chaotic oscillators is fused, specifically: Where Yi(ω) is the output response of the i-th intermittent Duffing chaotic oscillator array, α i is the fusion weight value, 2N+1 is the number of oscillators in the array, α i is the weighted coefficient of weighted average fusion, and Y(ω) is the fusion result of multiple intermittent Duffing chaotic oscillator characteristics.

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