Detection And Estimation Of The Weak Pulse Signal In The Chaotic Background Signal

As we all known,people has been suffering noise interference for long time,and more and more researches show that a lot of weak signals are embedded in the strong chaotic noise.The purpose of weak signal's detection and recovery is to detect useful signal from strong noise.Weak signal's detection and recovery is significance and has application value in signal processing area,in this paper,we propose an efficient hybrid processing technique.First,based on the short-term predictability and sensitivity to the tiny disturbance,a new method is proposed,which can be used for detecting and estimating of pulse signals in chaotic background that the nonlinear mapping is unknown.We reconstruct phase space according to Takens delay embedding theorem;then we will establish the local linear autoregressive model(LLAR)to predict the short-term chaotic signal and obtain the fitting error,and judge whether there are faint pulse signals or not.Second,we establish a single-jump model for pulse signals,and combines the local linear autoregressive model to build a double local linear model(DLL)to estimate the pulse signal.Double local linear model contains two parameters,and the two parameters influence each other.We adopt the back-fitting algorithm to estimate model parameters and ultimately recover weak pulse signals.Detecting and estimating of pulse signals in chaotic background turns into parameters' estimation of double local linear model.The minimum fitting error criterion is used as the objective function to get the estima tion of the parameters of the double local linear model(DLL).To make the estimation more exactly,we can calculate the formula of mean square error.The new algorithm is a simple algorithm,when we use it to detect and recover weak pulse signal,we does not need to know the priori knowledge of the chaotic system dynamics equations and weak pulse signal.Finally,the simulation results show that the methods is effective for detect and estimate weak pulse signals based on the chaotic background noise.Specifically,the weak pulse signal can be extracted well with low SNR,the minimum detection SNR reaches-196.9111(dB),and the minimum mean square error is about 8.89*10-10,and the minimum normalized mean squared error is about.5.21*10-7.The weak signal buried in chaotic background signal detection method is improved.