Research On Two-Dimensional Estimation Algorithm For Direction Of Arrival

DOA(Direction of Arrival)estimation is an important part of smart antenna.It plays a key role in locating the position of signal source.The study of two-dimensional DOA becomes a hot research field because of its precise in describing incident signal spatial characteristic information.In addition,the complex of propagation environment leads to the existing of lots of coherent signals.Because of these coherent signals' existence,many traditional algorithms lost their function.So,the research on the effective algorithm of coherent signals is also an important area in DOA.This thesis focuses on studying two-dimensional DOA estimation in smart antenna.The main works can be concluded as follows:Firstly,an introduction to research status and development trend of smart antenna and DOA estimation algorithms at home and abroad is given.There are also detailed instructions to the basic theoretical knowledge about this research,including the principle of DOA and the basic structure,principle,classification of smart antenna,and also the problems of two-dimensional DOA estimation.Secondly,aiming at the problem of large data redundancy and slow computation existing in the traditional two-dimensional ESPRIT DOA estimation algorithm,this thesis proposes an improved algorithm of two-dimensional ESPRIT based on MEMP after studying MEMP(Matrix Enhancement and Matrix Pencil)algorithm.This proposed DOA estimation algorithm applies L shape array,which gives full play to the advantages of small sampling data and fast calculation of MEMP,and combines with the superiority of PCA(Principle Component Analysis)in dimensionality reduction to extract the signal subspace.Simulation results show that this algorithm has faster computing speed compared with the traditional two-dimensional ESPRIT DOA estimation algorithm,and has good performance in solving angle ambiguity.Thirdly,for the problem of coherent signal source in practical application environment,the most common solution is spatial smoothing.However,this algorithm has shortcomings of a small number of estimated sources and poor accuracy of calculation.An improved algorithm of two-dimensional MUSIC algorithm based on matrix restructure is proposed in this thesis.Based on L shape array,this algorithm solves the problem of rank deficiency in the received data covariance matrix by constructing Toeplitz matrix.What's more,the proposed algorithm makes full use of the original data information by matrix's conjugate and restructure.After this preprocessing,angle estimation can be got by two-dimensional MUSIC algorithm.Simulations show this algorithm has higher precision compared with spatial smoothing,and also reduces the effective antenna array element loss.Finally,the summary and research prospect are given.