Research On DOA Estimation In Impulsive Noise Environment

At present,array signal processing as an important means of electronic countermeasures and electronic reconnaissance,in sonar,5G communication,radar,smart antenna,medical research and other military and civilian scenarios have been deeply studied and widely developed.Direction of Arrival(DOA)estimation is widely used in electronic countermeasures and electronic reconnaissance to improve the positioning accuracy of military equipment,and it is also an important branch of array signal processing.In recent decades,a large number of scholars have conducted extensive and in-depth research on DOA estimation under the condition of ideal additive Gaussian white noise,and obtained a series of DOA estimation algorithms.However,in the actual situation,because the sea clutter,ground clutter,atmospheric environment and radar scattering echo in nature may show rupture and peak value,so that the noise environment shows strong impact characteristics,and the noise deviating from the Gaussian distribution is called impulse noise.In this case,the performance of the algorithm based on ideal noise environment will be greatly reduced or even invalid.In order to solve the problem that the performance of traditional DOA estimation algorithms in the impulsive noise environment deteriorates or even fails,a new type of correlation entropy covariance matrix is proposed to replace the traditional autocorrelation covariance matrix,and the Gaussian kernel function can be used when the prior parameters of the noise are unknown.It can make full use of the advantages of suppressing impulse noise in the case of a uniform circular array,and combine the ESPRIT algorithm to realize the twodimensional DOA estimation under the uniform circular array,and use the alpha stable distribution to model the impulse noise.Simulation experiments are carried out under the number of snapshots and the characteristic index of impulse noise.The experimental results show that the algorithm can achieve accurate two-dimensional DOA estimation under the background of small signal-to-noise ratio,small number of snapshots and strong impulse noise.At present most of DOA estimation in the impulsive noise environment research are only applicable to situation of independent source,but in practice because of multipath transmission,and electronic jamming environment there are a lot of coherent source,so the detection and estimation of coherent source is an important research direction of DOA estimation,the source fully coherent,The rank of the covariance matrix of spatial electromagnetic wave signal data received by the array sensor will be reduced to 1.In this case,the performance of the traditional DOA estimation algorithm will be greatly reduced and the source arrival direction cannot be accurately estimated.Aiming at most of the DOA estimation algorithm under impulsive noise environment can only apply to independent source,conduct understanding coherence research,respectively is proposed based on the correntropy based correlation and new correntropy-based covariance matrix of the spatial smoothing algorithm,the array respectively after smoothing out the space before and after reconstruction related entropy covariance matrix and the new entropy covariance matrix,To achieve recovery due to reduced rank of coherent source,and uses the alpha stable distribution on pulse impulse noise is modeled in different SNR,fast,and the impulse noise characteristic index of simulation experiments have been carried out to verify the two algorithm proposed in this paper can in the case of coherent source good restrain impulsive noise effects.