Parameters Estimation And Beamforming Algorithms Research Based On High Frequency Electrically Small Vector Sensor

The High Frequency HF direction finding and receiving system is mainly composed of single-polarization scalar antenna for now.The direction finding system is mainly composed of whip antenna array and the receiving system is mainly composed of logarithmic cycle fishbone antenna and so on.This kind of scalar antenna can only sense the single projection of skywave in vertical or horizontal direction but has no ability to match three-dimensional electromagnetic wave in space without distortion polarization at any angle.The shortwave signal is mainly composed of skywave which is reflected by the ionosphere.Meanwhile,due to the effect of the geomagnetic field,skywave splits into ordinary wave and extraordinary wave which with opposite polarization states,proximate arrival time and angle.However,the traditional scalar array blurs these two modes of shortwave due to lack of polarization sensitivity,which also causes the limited direction finding accuracy and the severely affected demodulation and decoding,by frequency selective fading,in the end.Aiming at the limitation of the traditional scalar antenna in shortwave direct ion finding and receiving system,this paper studies the application of polarization-sensitive-electromagnetic vector antenna in shortwave direction finding and receiving system,mainly including set crossed-loop/monopole antenna as front-end sensor to carry out space-polarization domain parameter estimation algorithm in unknown and known application scenarios of signal sequence.Based on the estimated space-polarization parameters,this paper studies beamforming algorithm for shortwave multipath signal,separates and extracts the waveform of each path fro m space-polarization domain.The multipath could be weighted and synthesized after each path is aligned and synchronized fro m the time and frequency domains,which realizes the improvement of signal reception quality under multipath conditions.The main achievements and innovations of the paper can be summarized as follows:(1)For the spatial spectrum fuzzy problem and the arrival angle estimate problem happened in traditional rank-defect MUSIC algorithm in the un-constant modulus model of the three-dimensional vector antenna,this paper offers ways to improve the optimization goal of rank-defect MUSIC algorithm to eliminate the problem space spectrum of fuzzy to implement the robustness of the rank-defect MUSIC algorithm in the un-constant modulus receives model,and to extend the proposed algorithm application scenarios.(2)For shortwave signal waveform usually uses known longer code words as a training sequence,a spatial-po larization domain four-dimensional estimate algorithm in multipath condition use the training sequence and crossed-loop/monopole antenna is studied.Firstly extract steering vector of multipath signals from the correlation function of training sequence and multipath recieving signal,next combine the principles of Cauchy Inequality and generalized Rayleigh quotient,then proposes a new dimension reduct ion search cost function,to reduce the parameter search dimension from four to two.In this way great ly reduces the algorithm complexity and significantly enhances the realization of the algorithm.(3)For multipath is the one of the crucial reasons why frequency selective fading for shortwave,this paper proposes a synthesis method of multipath shortwave signal,which bases on the polarization sensitivity of crossed-loop/monopole antenna and takes advantage of the discrepancy in short-wave multipath signal polarization.It separately extracts multipath signals and then synthesizes respectively.The new method improves the received signal-noise ratio,reduces the multipath effect,and realizes the “reverse” application of unfavorable factors.(4)Based on the experimental conditions of a single three-dimensional vector antenna,the theoretical model of the antenna is verified.Employing the actual data collected by the antenna,the availability of the improved rank-defect MUSIC algorithm and the interference suppressio n ability of the beamforming algorithm in polarization domain.