Research And Implementation On Array Correction And Subarray Level Beamforming Technology

The background of this dissertation is a National Key Project named “Radio Detection Technique Based on Digital Array Antenna”.In this paper,key technologies of array signal processing,such as mutual coupling calibration,amplitude-phase error calibration,subarray beamforming technology,design and implementation of Digital Signal Processing(DSP)system are studied.In the first part,this dissertation studies the algorithms of amplitude-phase calibration and mutual coupling calibration.Firstly,the model of narrowband arrays in the presence of mutual coupling and amplitude-phase errors is established.Then three typical combined calibration algorithms for mutual coupling and amplitude-phase errors are studied and verified through computer simulation experiments.Furthermore,the performance of these algorithms is compared.Finally,in order to tackle wideband amplitude-phase errors calibration problems,an improved algorithm based on Fourier transform is presented,and simulation results show the effectiveness of the algorithm.The second part of this dissertation is maily about subarray level beamforming technology.Firstly adaptive wideband and narrowband beamforming technology is studied,and then methods of subarray partition are analysed based on grating lobe cycle.The relationship between grating lobe and number of two level subarray elements is studied,then the analytical expression and simulation results are given.Secondly,the algrothm in first two chapters are extended to subarray level,the analysis and comparison of the performance to the elements level is developed.Finally,multibeam technology for subarray level is studied.The effects of two level elements number,overlap number and beam number are analysised and simulated,and then design method for engineering implementation is put forward.In the third part,this dissertation studies the engineering implementation technology of Digital Array Radar(DAR).A system scheme with subarray structure is proposed based on a high-performance DSP platform.A high-speed data transmission system is design for the scheme.The calibration algorithms are verified by experiments in microwave anechoic chamber using a prototype of DAR system.Achievements in this dissertation provide high reference value in DAR,and giving technical support for the National Key Project.