Sidelobe Control Of The Adaptive Beam Broadening And Nulling

Digital Beam Forming (DBF) technique has been widely researched in modern radar and communication systems. Referred to sidelobe control and null widening for the fast and reduced rank adaptive beamforming, main works of this thesis include:(1) The principle of the QRD-SMI algorithm is discussed and analyzed, and the QRD-SMI algorithm is converted into Systolic parallel pipeline structure to improve its real-time processing capability. Low sidelobe of the beam is obtained by constraining the static steering vector Tschebyscheff coefficients. Simulation results verify the validity of the new low sidelobe algorithm.(2) First, based on the conventional Wiener filter, the reduced rank multistage Wiener filter is derived by means of adaptive interference canceling therory. Then the correlation subtraction algorithm (CSA) is introduced. Finally, low sidelobe control is proposed to the multistage Wiener filter. Simulation results verify the efficiency of the new low sidelobe algorithm.(3) A new algorithm that broadens the null width is proposed . Traditional algorithm is independent of the direction of the interferer and modifies the covariance matrix to get the wide nulling. And this method is applied to QRD-SMI algorithm based on Systolic array and the multistage Wiener filter by Khatri-Rao product. Simulation results verify the validity of the algorithm.