| Nowadays,with the development of science and technology,radar plays an increasingly important role in electronic warfare.Compared with conventional radar,the new radar system is also developing rapidly and has obvious differences in waveform design and radar antenna distribution.This will undoubtedly bring new challenges to the radar reconnaissance technology of various countries.Multiple Input Multiple Output(MIMO)radar is a new system radar that emerged in the new military background in recent years.It has great potential in various field due to the strong anti-interference performance and the research on reconnaissance and countermeasure technology of this radiation source signal is in urgent need of breakthrough.Experts and scholars from various countries are also increasingly investing in the research of MIMO radar.In view of the above situation,this paper takes five common MIMO radar signals as objects and focuses on the recognition and parameter estimation algorithms of MIMO radar signals.The specific contents are as follows:1.Through research and analysis,five orthogonal transmit signal models and the reconnaissance models of co-located antennas MIMO radar signals are researched and simulated.The characteristics in time domain and time-frequency domain are analyzed.The focus is on the analysis of frequency domain characteristics.All of these lay a foundation for the subsequent recognition and parameter estimation algorithm research.2 ?A joint recognition method based on FCBF and AdaBoost for the co-located antennas MIMO radar signal is proposed.This method avoids the complicated process of extracting artificial features.The FCBF is used to filter and reduce dimensionality of the frequency domain amplitude spectrum,and then the co-located antennas MIMO radar signal is recognized by using the AdaBoost algorithm for classification.3 ?Aiming at the formal similarity between distributed MIMO radar signal and conventional radar signal,an automatic recognition method for hierarchical decision based on instantaneous frequency and spectral features is proposed.According to the autocorrelation of the recognized signal itself and the cross-correlation analysis between the signals,the decision is made through two kinds of design principles of MIMO radar signal to achieve the purpose of recognizing distributed MIMO radar system.4?After modulation recognition of the co-located antennas MIMO radar signal,further research on parameter estimation algorithm is carried out.A code rate estimation methodbased on instantaneous frequency spectrum for QPSK-MIMO radar signal is presented,and an improved code rate estimation algorithm based on instantaneous frequency autocorrelation spectrum is also presented.For FC-MIMO radar signal,a chip number estimation method based on quadratic Fourier transform of square signal and an autocorrelation spectral code rate estimation method based on square signal are proposed.According to the time-frequency characteristics of LFM-MIMO radar signal,the multi-subcarrier STFT-Hough transform is used to estimate the modulation slope,the number of subcarriers and the frequency interval of the signal.The quadratic Fourier transform is used to estimate the number of chips of the M-LFMMIMO radar signal,so that the single chip signal can be extracted from the entire pulse signal.According to the multi-subcarrier characteristics of the single chip signal,the STFT-Hough transform algorithm implements parameter estimation for the number of signal subcarriers,the single chip modulation slope and the frequency interval. |
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