CN104268630A - Weak signal detection method based on Lu system - Google Patents

Abstract

The invention discloses a weak signal detection method based on a Lu system and relates to the technical field of signal detection methods. The method comprises the following steps that parameters of the Lu system are set to be a=36 and b=3; the value of a parameter c is determined, wherein the value of c is a critical value at which the Lu system is in a fixed point state, the value of c is determined through an equation and regulated from small to large, changes of an output y and a phase space of the Lu system are observed in the regulating process, and the value at which the fixed point state of the Lu system changes is used as the value of c; weak periodic signals are monitored through the Lu system with the determined parameters, and if a phase track is not in the fixed point state, it is judged that the weak periodic signals exist. According to the method, the Lu system is adopted, so that weak signals are recognized more easily, and the reliability is higher.

Description

Based on the method for detecting weak signals of L ü system

Technical field

The present invention relates to signal detecting method technical field, particularly relate to a kind of method for detecting weak signals based on L ü system.

Background technology

Along with the development of science and technology; the demand that feeble signal carries out detecting is day by day urgent; detect that feeble signal is developing high-tech, the important means of exploring and find the new natural law under extreme condition, significant to the development promoting the association areas such as national economy, national defense construction and environmental protection problem.Detection of Weak Signals is the technology that a kind of special and noise is struggled against in the sense, i.e. quick to feeble signal under very noisy, accurate, highly sensitive acquisition and processing is the new branch of science extracting useful signal from noise.

Feeble signal not only means that the amplitude of signal is very little, and mainly refer to the signal flooded by noise, faint is relative noise, in order to detect the feeble signal covered by noise, people have carried out long-term research work, analyze noise Producing reason and rule, the feature of research measured signal, the statistical property of correlativity and noise, to find out the method detecting useful signal from noise.The top priority of Technique of Weak Signal Detection improves signal to noise ratio (S/N ratio), this just needs to adopt electronics, information theory, computing machine and physical method, to detect useful signal from very noisy, thus meet the needs of modern scientific research and technological development, Technique of Weak Signal Detection is different from general detection technique, what its was focused on is not physical model and the sensing principle of sensor, corresponding signaling conversion circuit and instrument implementation method, but how restraint speckle and improve signal to noise ratio (S/N ratio), therefore can say, Detection of Weak Signals is the technology of a special restraint speckle.

For the measurement of various feeble signal, the such as low light level, weak magnetic, weak sound, thin tail sheep, small capacitances, micrometeor, micro-pressure, micro-vibration, tepor difference etc., general is all be converted into micro-electric current or low-voltage by corresponding sensor, amplify through amplifier, its amplitude is to indicating measured size again.But because measured signal is very faint, and the interference noise in the intrinsic noise of the background noise of sensor, amplifying circuit and surveying instrument and the external world is often much bigger than the amplitude of useful signal, the process of amplifying measured signal is also exaggerated noise simultaneously, and also must can add some extra noises, the inside intrinsic noise of such as amplifier and the impact of various external disturbance, therefore only can not Detection of Weak Signals out by amplification, under the condition of effective restraint speckle, only increase the amplitude of feeble signal, just can extract useful signal.In order to reach such object, the theory and technology method of Detection of Weak Signals must be studied.

Chaos system is one of most important achievement in nonlinear science, and application prospect is very wide, at present for fields such as control, communication, prediction, input.In Detection of Weak Signals field, chaos system has the advantage of some uniquenesses, both at home and abroad about the method utilizing chaos system to carry out Detection of Weak Signals mainly utilizes Duffing system, judge to there is feeble signal by chaos state to the change of great scale period state according to Duffing system, but change bad identification based on Duffing system Detection of Weak Signals state.

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of method for detecting weak signals based on L ü system, and described method is easier to the identification carrying out feeble signal, and reliability is higher.

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of method for detecting weak signals based on L ü system, it is characterized in that comprising the following steps:

(1) the systematic parameter a of L ü system and the value of b are set;

(2) by the value of above-mentioned two the parameter a and b set, determine the value of the parameter c of L ü system, then by ascending for the value of c adjustment, observe the change of phase space that L ü system exports y in adjustment process, the value during change of state of system being fixed a point is as the end value of c;

(3) the L ü system after determining parameter a, b and c value is utilized to carry out weak periodic signal detection, the signal of outside Noise is input in L ü system, observe the change that L ü system exports the state of y, if the phase path of y leaves fixed point state, then there is weak periodic signal in the signal inputted.

Preferred technical scheme is further: systematic parameter a=36, b=3 in described step (1).

The beneficial effect adopting technique scheme to produce is: (1) method for detecting weak signals is very directly perceived, by the change of recording geometry output signal y, can detect feeble signal very intuitively.(2) Detection of Weak Signals is implemented conveniently.(3) make use of L ü system to the susceptibility of feeble signal.(4) judge the change of Lu system state according to system y output and phase space, detecting reliability is higher simultaneously.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.

Fig. 1 is the L ü system chart for determining parameter c value;

The output waveform figure of Fig. 2 is L ü system when being fixed point state critical value y;

The phasor that Fig. 3 is L ü system when being fixed point state critical value;

The output waveform figure of Fig. 4 to be L ü system be y when leaving fixed point state;

Fig. 5 is the phasor of L ü system when leaving fixed point state;

Fig. 6 is the L ü system chart for Detection of Weak Signals.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only a part of embodiment of the present invention, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Set forth a lot of detail in the following description so that fully understand the present invention, but the present invention can also adopt other to be different from alternate manner described here to implement, those skilled in the art can when without prejudice to doing similar popularization when intension of the present invention, therefore the present invention is by the restriction of following public specific embodiment.

L ü system equation is:

（1）

Based on, be chaos state when a=36, b=3, c=20.

Equation for Detection of Weak Signals is:

（2）

Wherein, s(t) be signal to be detected, s(t) following form can be expressed as:

s（t）＝Fcost（t）+ σ ε（t）

Wherein, Fcost(t) be periodic signal, ε (t) for average be 0, variance is the white Gaussian noise signal of 1.

Utilize this equation to carry out Detection of Weak Signals to comprise the following steps:

Step 1: be a=36, b=3 by L ü system parameter setting.

Step 2, utilizes Fig. 1 to determine the value of L ü systematic parameter c, adjusts ascending for c parameter, is determined the value of c according to system state by the state of fixing a point to the change of non-fixed point state.As c=12.61, as shown in Figure 2, as shown in Figure 3, at this moment system is in fixed point state to x-y space phasor in the output of state y.Continue the value increasing c, as c=12.62, as shown in Figure 4, according to state y and x-y space phasor, x-y space phasor as shown in Figure 5, can judge that at this moment system is in non-fixed point state in the output of state y.

Step 3: utilize the L ü system after determining parameter, as shown in Figure 6, monitor weak periodic signal, if phase path leaves fixed point state, then judges to there is weak periodic signal.

Described method detects weak periodic signal by using L ü system, and method for detecting weak signals is very directly perceived, by the change of observation output signal y, can detect feeble signal very intuitively; Detection of Weak Signals is implemented convenient; Make use of L ü system to the susceptibility of feeble signal; Judge the change of Lu system state according to system y output and phase space, detecting reliability is higher simultaneously.

Claims (2)

1., based on a method for detecting weak signals for L ü system, it is characterized in that comprising the following steps:

(1) the systematic parameter a of L ü system and the value of b are set;

(2) by the value of above-mentioned two the parameter a and b set, determine the value of the parameter c of L ü system, then by ascending for the value of c adjustment, observe the change of phase space that L ü system exports y in adjustment process, the value during change of state of system being fixed a point is as the end value of c;

(3) the L ü system after determining parameter a, b and c value is utilized to carry out weak periodic signal detection, the signal of outside Noise is input in L ü system, observe the change that L ü system exports the state of y, if the phase path of y leaves fixed point state, then there is weak periodic signal in the signal inputted.

2. the method for detecting weak signals based on L ü system according to claim 1, is characterized in that: systematic parameter a=36, b=3 in described step (1).