Research On DOA Estimation Algorithm Based On Compressed Sensing

DOA estimation is one of the main research fields in array signal processing.DOA of spatial target signal is a very important parameter whether it is to detect the location of enemy signal source in electronic warfare or to detect the location of seismic source when an earthquake occurs.With a rapid development,DOA estimation algorithm based on compressed sensing has been widely studied.Compared to the traditional subspace algorithm,DOA estimation algorithm based on compressed sensing can properly estimate the DOA of the target in the case of low SNR or few snapshots,and can effectively distinguish the coherent sources.The prerequisite of using compressed sensing is that the angle of the target is on the predefined grid,otherwise,there will be a problem of grid mismatch.One of the direct methods to solve this problem is to divide more dense grids,however,this method may produce a highly correlation matrix of over complete dictionary which can result in high computational complexity and low reliability of signal reconstruction.This thesis mainly studies the problem of DOA estimation based on compressed sensing in the case of grid mismatch.The whole content of this thesis is as follows:1.Several classic DOA estimation algorithms are studied,including traditional subspace algorithms,IAA-APES and DOA methods based on compressed sensing theory.Simulation and experiments verify that DOA methods based on compressed sensing theory estimate the angle of target more accurately than other algorithms when the sources are coherent.2.To solve the problem of grid mismatch,the alternating iteration algorithm based on the first order Taylor expansion correction model is studied.And the algorithm is improved in this thesis.It can get the angle of target faster using the algorithm.And it can improve the efficiency of calculation and the performance of DOA estimation.Simulation results verify the effectiveness of the algorithm.The improved algorithm is applied to monostatic MIMO radar to estimate DOA in the case of grid mismatch and it can estimate the angle of target accurately.Simulation results verify that the improved algorithm can enhance the accuracy of DOA estimation of monostatic MIMO radar in the case of grid mismatch.3.The angle estimation algorithm of bistatic MIMO radar in the case of grid mismatch is studied.Firstly,the joint sparse recovery method is applied to monostatic MIMO radar.However,the joint sparse recovery model cannot fully determine the position of the target relative to the transmitting and receiving array.Then the improved algorithm is applied to bistatic MIMO radar.Simulation results verify that it can accurately estimate the DOD and DOA of targets.