Research On Array Signal Adaptive Algorithm Based On FPGA

With the continuous development of array antenna theory and array signal processing technology,the research and application of direction estimation technology based on array antenna are more and more widely,which has great significance in radar direction finding,navigation guidance and mobile communication,and has been widely concerned by scholars at home and abroad.Array antenna technology can generate spatial directional beam according to the changing signal environment,so that the main beam of antenna is aligned with the direction of arrival of user signal,and the sidelobe or null is aligned with the direction of arrival of interference signal,so as to enhance the desired signal and suppress interference and noise.Compared with other technologies,the application of array antenna in positioning system has a very broad development prospect because of its outstanding advantages.Therefore,this paper first analyzes the development history and current situation of array antenna,adaptive beamforming,direction of arrival estimation and digital signal processing technology;According to the basic principle,classification and system architecture of array antenna,(why circular array)the uniform circular array model and pattern are derived through arbitrary array model.Then the influence of circular array parameters on beamforming performance is simulated and analyzed.It is concluded that the performance of beamforming is related to the number and radius of circular array elements.This paper compares the advantages and disadvantages of the classical adaptive criteria,and then classifies the algorithms in adaptive beamforming,and studies the classical adaptive beamforming algorithms: least mean square error(LMS)algorithm and recursive least square algorithm(RLS).The algorithms are simulated and compared.How to improve LMS adaptive algorithm is introduced,and the improved algorithm is verified by simulation.Then,this paper uses DSP Builder,a digital signal processing tool of FPGA,to complete the design of array adaptive beamforming system based on LMS algorithm and improved LMS algorithm.The simulation results show that the designed system has good filtering performance for signals.The analysis of hardware speed shows that the speed of adaptive beamforming system based on improved LMS algorithm is nearly twice that of adaptive beamforming system based on LMS algorithm.Finally,this paper studies the DOA estimation of two-dimensional array and uniform circular array,and proposes a dimension reduction MUSIC algorithm based on special area array model.This algorithm can avoid the ultra-high computational load caused by the two-dimensional peak search of two-dimensional MUSIC algorithm,and the angle estimation performance of this algorithm is close to that of two-dimensional music algorithm.Finally,the ESPRIT algorithm without spectral peak search is studied,and the matching of azimuth and elevation is achieved successfully.Compared with music algorithm,the computational complexity of ESPRIT algorithm is lower.The two algorithms are applied to the uniform circular array,and the simulation analysis is carried out.