Angle Measurement Technology Of Radar Under Complex Environment

One of the main tasks of radar signal processing is to measure target information.Target angle estimation is the most basic and important research content in measuring target information in radar field.With the breadth and depth development of modern science and technology and the enhancement of the fields of radar application,the electromagnetic environment in which radar operates has become more complex,and the problems associated with estimating the target angle are increasing day by day.The radar always estimates the target angle in the complex electromagnetic environment such as different forms of noise,interference and clutter.However,the traditional angle measurement method cannot obtain effective angle information,which actively controls the efficiency of radar angular measurement.Therefore,the study of radar angle measurement technology has great practical importance in complex situations.This thesis mainly studies the radar angle measurement technology in complex environment.Firstly,the thesis introduces two basic principles of radar target angle estimation（using the phase or amplitude of the signal echo）and two conventional angle measurement methods（the monopulse angle measurement method and the array scanning method）.In this thesis,theoretical analysis and simulation verification are carried out on the symmetrical inversion sum-difference method（sum-difference method for short）and bidirectional amplitude ratio method in the single-pulse angle measurement method.In this thesis,the array scanning method is also simulated and analyzed to analyze its angle measurement performance.Then,aiming at the radar angle measurement problem in the case of strong sidelobe interference in the interference environment,this thesis analyzes the adaptive sum-difference sidelobe cancellation method,the MUSIC algorithm and the ₁l-SVD algorithm and OMP algorithm in the CS-DOA algorithm in detail.Computer simulation experiments verify the validity and effective coefficients for measuring the angles of the above algorithms in their respective applicable conditions.Finally,aiming at the angle measurement problem of machine-scanned radar in cluttered environment,this thesis studies the sum-difference angle measurement method based on MTI and MTD from two aspects of theoretical formula derivation and computer simulation analysis,and this thesis proposes an improved sum-difference method based on MTD processing,which further improves the angle measurement accuracy.Aiming at the angle measurement problem of radar that can scan both mechanically and electronically in azimuth under clutter environment,this thesis studies the angle measurement method based on the inter-pulse adjustment of beam pointing,avoiding the SNR loss caused by the antenna rotation and effectively improving the angle measurement accuracy of the radar in the clutter environment,and this thesis analyzes the effect of the number of antenna phase shifters on the inter-pulse adjustment of beam pointing.