Application Of FO-MUSIC Algorithms To Wide-Beam HF Ground Wave Radar

This thesis makes use of higher-order statistics in array signal processing of HF-GWR and discusses the application of fourth-order cumulant in estimating arrival-of-direction of currents and targets. The purpose of this application is improving detecting capability of low SNR(Signal Noise Ratio), increasing DOA(Direction of arrival) estimation precision and providing theoretic basis of farther miniaturization of antenna array.At first, the properties of cumulants and the processing of FO-MUSIC(forth-order cumulant MUSIC) algorithm are introduced. Then. It is shown howFO-MUSIC can be used to restrain effect of Gaussian measurement noise andincrease the effective aperture of an arbitrary antenna array and improveperformance of FO-MUSIC algorithm in the presence of sensor perturbations.Simulation is done in this paper to study in algorithm's performance under differentsea condition. Furthermore, a method is put forward to estimate both signal numbersand signal directions by using the characteristic of FO-MUSIC algorithm. It estimatessignal numbers and its position by trial and error method. This method has also beenapplied to the signal processing of OSMAR2000's target detection and sea statedetection experiment, which demonstrate its validity and more effective thanSO-MUSlC(second-order cumulant MUSIC) algorithm. According to results ofexperiment, it is proved that the presence of a doublet and use of fourth-ordercumulant is sufficient to improve radar's precision, reduce requirement of SNR insignal processing and make further detection of the radar.