Research On Robust Beamforming And Interference Suppression Algorithm Of Wideband Phased Array

Wideband beamforming and interference suppression technology plays an important role in phased array radar research.Nonideal factors will cause the performance of traditional wideband beamforming and interference suppression algorithms to decline sharply.The introduction of reasonable and effective robust design can greatly improve the robustness of the algorithm.In this paper,the wideband robust beamforming and interference suppression techniques for phased array radar receiving wideband signals are studied.The main research work is as follows:1.The narrowband signal model and wideband signal model of linear array are introduced.The principle of broadband beamforming is described in detail.2.There are two types of broadband robust design based on data independence:beamforming algorithm based on space-frequency structure and beamforming algorithm based on space-time structure.The traditional beamforming algorithm establishes a convex optimization problem,sets the position and shape of the main lobe and the size of the side lobe level in its constraints,and then uses the convex optimization tool to calculate the weight vector to realize beamforming.When the interference moves rapidly and the airspace range of the interference is known,the wide NULL constraint is introduced into the constraint conditions,which can also increase the ability of the algorithm to resist such interference.Based on word algorithm and space-time adaptive beamforming algorithm with frequency shift invariance,a new broadband beamforming algorithm is proposed in this paper.Compared with convex optimization beamforming algorithm,this algorithm has the advantage of analytical solution and less computation.The performance of these algorithms is studied by simulation.3.When the angle of jamming signal is unknown,a variety of adaptive broadband robust beamforming and interference suppression techniques are studied.The influence of various nonideal factors on the adaptive robust algorithm is simulated and analyzed.The adaptive algorithms include: traditional space-time LCMV algorithm,diagonal loading algorithm,two worst performance optimization algorithms,two steering vector estimation algorithms.The nonideal factors are: DOA mismatch of expected signal,the channel amplitude error,the channel phase error and the array element position error.4.When the expected signal information exists in the covariance matrix,the performance of the adaptive beamforming algorithm drops sharply.However,in some scenarios,the covariance matrix containing only the interference signal cannot be obtained directly from the received data.To solve this problem,several robust beamforming and interference suppression algorithms based on covariance matrix reconstruction are explored.In addition to the simple covariance matrix reconstruction algorithm,there are also such algorithms based on time-frequency analysis or uncertainty set.In the later simulation stage,the broadband robust algorithm based on covariance matrix reconstruction under different negative factors is studied.