Research And Implementation Of Single Pulse Angle Measurement And Difference Beam Forming Algorithm

Monopulse angle measurement with sum-difference beamforming is widely used in tracking radar for its excellent performance in interference suppression and real-time angle estimation.In view of practical engineering applications,this thesis does research on the fast sum-difference beamforming with interference space orthogonal projection,joint iterative optimization adaptive sum-difference beamforming,interference suppression focusing transformation algorithm for wideband coherent beamforming.The main contributions are illustrated as follows:1.With a large digital array radar,a fast sum-difference beamforming algorithm with interference space orthogonal projection is proposed to reduce the computational complexity.First,estimate two dimensional spatial spectra of interference in sidelobe by FFT and span the interference space.Then,map the quiescent weights of sum-difference beamforming to the orthogonal space of interference space to suppress the interference.Several simulations of the proposed algorithm have been provided which shows advantages in interference nulling,sidelobe level,angle estimation and real-time performance.2.Motivated by beams distortion in the conventional constrained adaptive beamforming with multiple constraints,the thesis proposes a novel joint iterative optimization method for adaptive sum-difference beamforming in monopulse angle estimation.The algorithm optimizes the adaptive weights of sum-difference beams jointly,utilizing the constraints of array gain and monopulse ratio curve to avoid beams distortion while nulling the interference.The simulations results show that the proposed algorithm has a significant improvement in beamforming and angle estimation performance.3.Frequency domain processing method in wideband beamforming is investigated.To null the interference in focusing transformation,an interference suppression focusing transformation(ISFT)algorithm is proposed.Simulation results prove that the ISFT ensures good beamforming appearance and excellent interference suppression performance which is not sensitive to prior angle estimation error when signals are correlated.4.The fast sum and difference beamforming algorithm with interference space orthogonal projection is transplanted and verified through developmental DBF system.The feasibility is proved with real-time remarkable performance in angle estimation.