Research On GNSS Antijamming Algorithms For Polarization Sensitive Arrays

Recently,polarization sensitive arrays（PSAs）have generally been used in suppress-ing jammings,especially with the reception of the navigation signals.For polarization sensitive arrays,beamforming algorithms could effectively receive the signal of inter-est（SOI）corrupted by interferences,exploiting the polarization characteristics of signals,compared to the saclar arrays.The PSAs have important research significance and ap-plication value in receiving signals corrupted by jammings.However,most of these ex-isting beamforming algorithms for the polarization sensitive array are usually applied to the static interferences or the Gaussian circular interferences without considering the dis-turbance of direction and the non-circularity of interferences.Therefore,the performance of these algorithms is not optimal or degraded for the high dynamic or non-circular in-terferences.This thesis mainly considers effectively receive the potentially non-circular SOI corrupted by potentially high dynamic or non-circular interferences for polarization sensitive arrays.The main contributions and research contents areA widely linear（WL）model has been implemented for the high dynamic and poten-tially non-circular interferences for polarization sensitive uniform linear array.According to the theory of the covariance matrix taper（CMT）,both the CMT and the complemen-tary CMT in the polarization domain and the space domain have been derived,respec-tively.Then,the second-order statistics of the WL-PSA and the corresponding CMT are obtained.A robust null broadening algorithm for non-circular interference suppression endowed with the WL-PSA have finally been proposed.Then,the adaptive beamforming problem in terms of the constrained minimization of the Gaussian entropy of the polarization sensitive uniform linear array output signal has formulated in the thesis,subject to the distortionless constraint of the SOI.Based on the minimum Gaussian entropy criterion,a distortionless beamforming algorithm has been proposed taken into account the non-circularity of the received signals,and herein been considered solving beamformer weight in an adaptive manner.Leveraging the stochastic gradient methodology,a adaptive quasi-steepest-descent beamformer,as well as a adap-tive stochastic gradient beamformer,have been developed for the reception of a second-order non-circular/circular SOI.The sufficient conditions for the convergence and the distortionless of the proposed algorithms are derived.Illustrative simulations show the superior performance of the proposed beamformers.Slow convergence rate and high computational complexity would generally hinder practical applications of the conventional adaptive beamforming algorithms for large-scale polarized arrays.A distortionless adaptive beamformer has been developed in this thesis for the reception of a second-order non-circular SOI of a large-scale polarized antenna array endowed with the property of multilinear translation invariance（MLTI）.By the tensor decomposition theory,the global array has been separated into several sub-arrays to accelerate the convergence rate with considerably reduced computational complexity.Thus,in this thesis,the constrained Gaussian entropy minimization of the tensorial beam-former output has been formulated,subject to the distortionless constraint of the SOI.A minimum Gaussian entropy distortionless response based tensorial stochastic gradient（MEDR-TSG）beamforming algorithm has been developed.Illustrative simulations vali-date the superior beamforming performance of the MEDR-TSG algorithm for large-scale polarized arrays.