| The signal system and propagation envirment of the modern radar were changed greatly, along with the application and development of the radar techniques. Furthermore, the spans of the time, frequecy and space of the modern radar are very large, non-stationary and the coherent interference or short sequences appear frequently. The researches on multi-parameter estimation methods applied in the circumstance of the modern radar signals were advanced problem in the information domain. The estimation algorithms of spatio-temperal multi-parameters in the modern electromagnetic envirment were focused in this dissertation. The main contributions of this dissertation concentrate in a few aspects as follows:1. The time-frequency analysis tools applied in the nonstationary radar signals is discussed. And a new reduced crossterm distribution for linear frequency modulated(LFM) signals is presented. This approach is the modification of the Wigner-Ville distribution(WVD), which surppresses crossterm by segment compensation and smoothing.2. The time-frequency detection methods and character parameters estimation methods based on the dechirping are analysed. In order to deal with the LFM signals in the ultra-low signal-noise-ratio(SNR) case, a nonlinear algorithm for weak chirp signal detection and parameters estimation is presented. The generalized filter array is constructed by the Duffing oscillator, and Lyapunov exponential is exploited to judge the state of the system. According to the characteristic of the chirp signal, the problem of chirp signal detection is transformed to the period detection problem, which is satisfied the demand of Duffing oscillator system. Moreover, the segmented correlation smoothing method is proposed to enhance the SNR that improved the performance of the method.3. The narrow band model of the array output is analysed, and the conventional subspace methods combining the time-frequency analysis are introduced. To coherent interference, a novelty direction-of-arrival(DOA) estimation method is proposed exploiting the characteristic of pulse radar. K coherent signals can be processed with K+1 arrays sensors in this method. Moreover, the algorithm exhibits litte astrict to array geometries. The direction finding of the short sequences is investigated, and a modified pseudo-covariance and DOA estimation algorithm is presented.4. The wideband models of the array output were discussed, according to the alternative nonstationary radar signals, the simplified model and complete model of the wideband LFM signals are derived respectively, as well as wideband symmetric triangle LFM(STLFM) signals. And then, the DOA estimation methods for wideband LFM signals based virtual WVD, for wideband LFM signals based ambiguity transformation and for wideband STLFM signals based data segment virtual elements are proposed respectively. The simulations illustrate that the proposed approaches have higer precision and less computation than conventional TF-CSM methods.5. The multi-parameters estimation problems with polarization sensitivith anttenas array are studied. The algorithms of evolutionary period spectrum combing crossed dipole array and fractional Fourier transformation(FRFT) combing vector sensor array are presented respectively, which can implement the hgier accurate joint DOA and polarization estimations for LFM signals. The space-polarization freedom degree dividation was proposed, thus, the DOA and polarization of coherent signals are estimated with vector sensor array. Analysing the information strcture of the cross diploes, a DOA and polarization estimation method is presented for broadband signals. An new array with separated dipoles is proposed to obtain the joint DOA and polarization estimation for avoiding the mutual coupling of co-center poles.6. The problem of the joint DOA and time-delay estimation is discussed. For estimating the DOA and time-delary of the radar echo signals, a novelty high resolution and presicion algorithm is presented.
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