Research On Radar Signal Recognition And Parameter Estimation Under Alpha Noise

At present,the war between countries gradually evolved from military confrontation to electronic confrontation.In the war of electronic countermeasures,the electronic detection equipment of the opponent plays a key role,and the key information of the electronic detection system is the identification and parameter estimation of radar radiation source signal.The purpose of this paper is to study the problems existing in the identification process of various radar signals in order to obtain useful electronic intelligence information in the complex noise environment.Common radar radiation signals in electronic warfare include Linear Frequency Modulation(LFM)signal,Frequency hopping signal,Binary Phase Shift Keying(BPSK)signal,etc.In this paper,the identification and parameter estimation methods of the three signals are studied.In the process of frequency hopping signal,LFM signal and BPSK signal processing,gaussian distribution is usually used to simulate the background noise.However,in the actual process of signal transmission exists non-gaussian distribution of interference,the type of noise has a strong pulse radar waves,for example,low-frequency atmospheric noise,etc.,many scholars study found that Alpha stable distribution can describe such a strong pulse characteristics of noise,under the background of this kind of impulse noise,the conventional processing method based on gaussian distribution performance degradation or even failure.To solve this problem,this paper focuses on the identification and parameter estimation of various radar signals under the stable distribution noise of Alpha.The main work is as follows:First by Short Time Fourier Transform(Short Time Fourier Transform,STFT)and Wigner Distribution Willie(Wigner-Ville Distribution,WVD)these two kinds of time-frequency analysis method respectively to three kinds of radar signal time-frequency analysis,the second in the background noise to join Alpha noise and gaussian noise respectively,by comparing the found in Alpha noise under the background of the performance of the two methods.In Order to effectively analyze radar signals under Alpha noise,this paper USES the method of Fractional Lower Order Moment(FLOM).Based on the theory of flo-wvd and flo-stft,the identification of LFM signal,frequency hopping signal and BPSK signal is studied.The simulation analysis shows that this method can recognize three kinds of radar radiation source signals under the background of Alpha noise.Finally,according to the time-frequency image of LFM signal and the traditional Hough transform theory,the flowvd-hough transform algorithm and flostft-hough transform algorithm are used to estimate the parameters of LFM signal.The time frequency image of frequency hopping signal is used to extract the peak sequence,and the new sequence is combined with the fast Fourier transform to estimate the parameters of frequency hopping signal;For BPSK signal,the instantaneous frequency is extracted by flo-stft,and the instantaneous frequency is processed by setting threshold value,and then the parameter estimation of BPSK signal is carried out.Simulation results show that the above methods caneffectively estimate the parameters of three kinds of radar signals under the condition of Alpha noise.