Research On Some Aspects Of High Resolution Direction Of Arrival Estimation

High resolution Direction-Of-Arrival (DOA) estimation techniques with arrayantenna have wide applications in a variety of fields ranging from radar,communication,sonar,seismology to radio astronomy.Especially,they become a key technique in thepassive detection of array radar,SDMA of smart antenna system and detection soundsource.Since early 1980s,high resolution DOA estimation techniques have receivedconsiderable attention and a lot of significant progresses have been achieved in this field.However,there are still important and urgent problems that have not been solved perfectlyin their engineering practice.This thesis centers on two problems in practice.One is theDOA estimation of coherent sources and another is array calibration.The maincontributions can be summarized as follows:An algorithm for DOA estimation of coherent source,called correlation vectorToeplitz (CVT) algorithm,is proposed with the correlation coefficient is 1.And anotherECVT algorithm is proposed using maximum eigen-vector based CVT.Compared withspatial smooth algorithms,the new methods have no loss array aperture,and have lowcomputational complexity.Therefore,the new methods have higher estimationperformance.Based on the CVT algorithm,the new Generalized Maximum Likelihood (GML),Generalized Signal Subspace Fitting (GSSF) and Generalized Noise Subspace Fitting(GNSF) are derived.This kind algorithm uses generalized steering vector substitutes forthe conventional steering vector.Therefore,the number of sources resolved by newalgorithm can be larger than the number of sensors as long as the number of the coherentgroup is smaller than the number of sensors.The GCV method was applied to meter radarverify system.The DOA estimation performance was compared using experimental data,demonstrating the effectiveness of new method.Passive radar has attracted great research interest given their importance in amilitary application field.The new interference jamming method (IJM) is presented toestimate the weak target under the condition of presence large power interference of known direction.The method use the information of the strong jamming is known toconstruct a jam matrix,and then estimate signal DOA of the low signal noise ratio in onesector.The method can be applied to the passive array radar based civil broadcastingstation.And the relation of the transform matrix and the restrained interference noisematrix is analyzed.A new orientation estimation and mutual coupling auto-adjust algorithm is proposedto solve the elements mutual coupling problem based on subspace theory and the specialstructure of parallel linear array in this paper.The proposed algorithm can estimateaccurately DOA of signal sources without known the mutual coupling parameters of array.Then the estimated orientation can be used to estimate mutual coupling parameters,whichcan adjust the mutual coupling problem of array.The estimation of DOA only needs onedimension spectrum peak value searching,which avoid the multidimensional jointestimation.The algorithm decreases the computational load,and it has high estimationprecision and good mutual coupling adjusting ability.Based on parallel linear array,a novel Instrumental Sensors Calibration Position(ISCP) method is proposed to estimate the sensor position error or channel gain error.Andanother new method of Instrumental Sensors Calibration Position and Gain (ISCPG) canestimate the sensor position error and channel error same time.The DOA and errorparameter can be completed just using a one-dimensional search or polynomial rooting,with no high-dimensional nonlinear search and convergence burden involved.Another,theISCG method was applied to passive array radar verify system.The proposed algorithmcan estimate accurately target without known the channel gain error of array usingexperiment data were processed to verify systems.