Research On Identification And Parameter Estimation Of Intra-pulse Modulated Signals At Low SNR

With the complexity and variety of modern electronic battlefield environments,conventional pulse parameters are increasingly unable to effectively describe the nature of radar signals,and research on radar subtle features is becoming more and more important.In this paper,by studying the subtle features in the intra-pulse,we make it provide valuable help to the signal recognition of radar emitter signals,and then carry out effective reconnaissance and interference to the enemy radar.This paper is for Normal Signal(NS),Linear Frequency Modulated(LFM),Double Linear Frequency Modulated(DLFM),Polynomial FM Signal(PPS),Bibary Phase Shift Keying(BPSK),Quarter Phase Shift Keying(QPSK),M-ary Phase Shift Keying(MPSK),Frequency Shift Keying(FSK),Frequency Shift Keying and Bibary Phase Shift Keying(FSK-BPSK),Linear Frequency Modulated and Bibary Phase Shift Keying(LFM-BPSK)for identification and parameter estimation and the model S frequency modulation signal is studied.Firstly,the fractional Fourier transform is studied.The two-dimensional search algorithm is used to accurately search the matching order of each signal and analyze its corresponding spectrogram.Then the phase information of the intra-pulse signal,combined with delay correlation algorithm,multiple difference and linear regression is studied.By combining the matching order ,fractional spectrum and order diagram with various algorithms,10 kinds of signals are effectively recognized when the signalto-noise ratio exceeds-10 dB.Secondly,based on the recognition results,the second-order moment fourth-order moment method,the modified Rife algorithm and the multi-scale haar wavelet transform are used to accurately estimate parameters of signal when the signal-to-noise ratio is above 0 dB.Finally,the phase lingering principle and the S-type FM signal are derived.The phase difference algorithm,wavelet transform and the time-frequency diagram are used to identify the S-type FM signal.In order to verify the effectiveness of the algorithm,a large number of simulation experiments are carried out in this subject by MATLAB.The analysis method provided in this paper is to summarize the previous studies that the radar intra-pulse signal cannot be recognized and the estimation accuracy is low under the condition of low SNR.This article creatively put forward the research on identification and parameter estimation of Intra-pulse modulated signals at low SNR,the design and signal recognition of s-type FM signal.Provide valuable technical reference for the identification of the radiation source signal.