| Modern radar technology develops rapidly and has been widely used,among which the use of radar for high-precision,high-resolution azimuth estimation has become one of important studies.In practical DOA estimation,it is hoped that the structure of radar system will be simplified as much as possible and the cost will be as low as possible while maintaining the performance of high-precision and high-resolution DOA estimation.Based on this,this thesis presents a TDM MIMO radar system using sparse array,focusing on its structure,working principle and azimuth estimation algorithm.The main contents of this paper are as follows:1.The system of MIMO radar using LFMCW are studied.The classical DOA estimation algorithm——MUSIC algorithm,is applied to MIMO radar system and simulated.2.Aiming at the sparse array radar system,the methods of optimization design are studied,including the minimum redundancy linear array configuration and the array optimization method based on genetic algorithm(GA).By comparing the optimization results of the two methods,GA is selected to optimize the sparse array proposed in this paper.3.The system of TDM MIMO radar using sparse array is introduced in detail.MUSIC algorithm is applied to the system,and the DOA estimation performance of targets in moving and stationary states is analyzed by simulations.The results show that the system can achieve high-precision,high-resolution angle estimation under static targets,while under dynamic targets that will be significantly reduced due to the influence of frequency migration and phase error.4.Aiming at motion-induced frequency migration in sparse array TDM MIMO radar system,a method based on Keystone transformation is proposed to correct the migration.Then FFT is proposed for the phase error.At last the validity of the methods are verified by simulations.It ensures that the system still has high precision and high resolution DOA estimation performance at low cost and complexity. |
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