Study On The DOA Estimation For Coherent Signals With Electromagnetic Vector Sensor Array

Array signal processing is important means of the signal analysis.It is widely applied in radar, sonar, communication, seismic exploration and medical imaging etc. Array signal processing is using plenty of sensors in different locations in the space composition to form a sensor array, through which signals of the space are received and processed to get the temporal and spatial multi-dimensional signal. That's how detection and extraction of its parameters is completed. The polarization state and DOA are the most important characteristic parameters for space of electromagnetic signals and they carry important information of electromagnetic signals. Signal DOA describes the position of signal source in space, while the polarization describes the characteristics of electromagnetic wave motion vector, which is the intrinsic property of electromagnetic wave. The traditional scalar sensor array can estimate the signal power, frequency, time delay and to estimate direction, but not the polarization. Electromagnetic vector sensor array can not only obtain the angle of signal in the space, but also can get information of signal polarization. Compared with traditional scalar sensor array, electromagnetic vector sensor array, has several advantages:strong anti-jamming ability, stable capability. The system has high resolution and polarization multi-access ability.In practical engineer project, we often encounter with coherent sources. In radar or sonar system, when there is target with multipath or multiple target signals, receipt of the echo is key issues of coherence estimation problem. When the wave signals are coherent, the covariance of the classical MUSIC algorithm and the ESPRIT algorithm cannot divide signal subspace and noise sub-space, which causes algorithm failure. So this paper studies the DOA of coherent sources and the polarization parameters estimation problem.Firstly, based on the polarized uniform linear array, we combined with spatial smoothing technique, described the cycle MUSIC smoothing algorithm for the coherent cyclostationary signals. Subsequently, the basis of Toeplitz matrix regrouping DOA coherent sources estimate method is studied. The smooth circulation of coherent sources estimate DOA gives effective estimates, and in the circumstances, the pore arrays to further improve the performance.Furthermore, the signal sparse linear array model is also analyzed, the inhomogeneous linear array elements configuration and the estimation of the fuzzy array signals are discussed. At last, based on the cycle of electromagnetic vector sensor smoothing algorithm, DOA and polarized coherent signal parameter estimation problem is discussed under the sparse linear array with simulation experiment verified.