Short-wave Signal Parameter Estimation And Receiver Design Based On Polorization Sensitive Array

The short-wave signal is reflected by different ionospheres to achieve long-distance transmission,and the received signal has obvious multipath effect.Existing short-wave communication systems often use single-polarization antennas to receive signals.This type of antenna can only sense spatial information and is blind to the polarization characteristics of electromagnetic waves.When short-wave signals are reflected by the ionosphere,it is difficult to distinguish multipath signals with relatively close arrival angles.This thesis mainly models the multipath receiving signal of the polarization-sensitive array for short-wave,completes the multipath signal parameter estimation,and designs the polarization domain-space domain short-wave multipath Rake receiving scheme,and uses joint filtering to separate the multipath signal to obtain Combined gain to enhance the receiving quality of short-wave signals.Aiming at the receiving model of array and array element,this thesis studies the signal polarization domain-space domain multi-dimensional parameter estimation method.Due to the rank deficit phenomenon of the monopole-crossed loop antenna structure,it will lead to the problem of ambiguous peaks in the direction parallel to the surface incident.This thesis proposes a dimensionality reduction MUSIC(Multiple Signal Classification)algorithm based on the matrix rank deficit principle to normalize the spatial spectral function.The improvement removes the influence of the fuzzy peak of the original algorithm,and expands the scope of application of the dimensionality reduction MUSIC algorithm.When the signal-to-noise ratio is 8d B,the RMSE of the multi-dimensional parameters are all less than 2°.At the same time,aiming at the single-array element receiving model,using the known sequences in short-wave communication,a multi-dimensional parameter estimation algorithm based on PARAFAC(Parallel Factor Decompose)is proposed.Firstly,the estimated channel matrix in frequency domain is reorganized and decomposed,and then the TALS(Trilinear Alternating Least Square)algorithm is used to estimate the steering vector matrix.The polarization domain-space domain parameters of the multipath signal are obtained through the closed-form solution,which avoids the possible underdetermined problem of the MUSIC algorithm.When the signal-to-noise ratio is 16d B,the RMSE of the multi-dimensional parameters are all less than 4°.In addition,considering the amplitude and phase errors in the array,this thesis designs an iterative self-correction algorithm based on subspace orthogonality.In each iteration,the improved dimensionality reduction MUSIC algorithm is used to estimate the signal parameters and solve the minimum value of the cost function Estimated amplitude and phase error.At the same time,a self-correction algorithm based on the maximum likelihood criterion is proposed,which uses alternating projection to decompose the multi-dimensional parameter search,and then iteratively updates through the Gauss-Newton iterative method to complete the joint estimation of polarization domain-space domain parameters and amplitude and phase errors.When the signal-to-noise ratio is 20d B,the parameter estimation RMSE of the two self-calibration algorithms is maintained at 3°and 2°,respectively.In order to make full use of the multi-dimensional parameters of the short-wave multipath signal obtained by the polarization-sensitive array,this thesis designs a polarization domain-air filter Rakereceiving scheme based on the MIL-STD-188-110C protocol,which converts the original multipath interference into diversity Gain,using the difference in polarization state of multipath signals to separate multipath signals,eliminate intersymbol interference caused by multipath,and reduce the impact of multipath fading.When the bit error rate reaches the order of 10-4,the separated single-path signal has a performance gain of 6d B compared with the single-channel signal.Considering the fading independence of each path signal,a space-time joint estimation algorithm is further proposed.Through adaptive combined for an additional 5d B of gain.Greatly improved the quality of short-wave signal reception.