The Research On Monopulse Angle Measurement For Digital Phased Array

Monopulse technic has developed for decades and makes a great progress.It has lower algorithm complexity and convenient scheme compared with other methods.Therefore,we focus on monopulse methods with phased array system.This thesis is organized as follows:In the first section,mathematical model of digital phased array system is discussed,which includes common regular and conformal arrays.We proposed different models of these arrays and introduced beamforming technics.Also,three conventional monopulse methods and their performance are discussed in this section.In the second section,three monopulse methods suppressing sidelobe jammings are investigated.Pattern synthesis is discussed including linear programming and difference evolution algorithm.Then we discussed generalized sidelobe canceller(GSC)and investigated a method to design blocking matrix which is based on singular value decomposition(SVD).Using this blocking matrix and GSC,we could suppress sidelobe jamming and estimate direction simultaneously.In the third section,monopulse estimation in mainlobe and sidelobe jammings is discussed.Four methods are illustrated in this section including maximum likelihood,MVAM,linear constraints and SVD linear constraints.About linear constraint method,the performance is inefficient when the pattern mainlobe is broad.Thus,we proposed a SVD linear constraint method which corrected this method by SVD to approximate original constraint matrix.As a consequence,the precision is improved using less freedom-ofdegree as much as possible.In the last section,we expanded monopulse estimation into polarization and investigated monopulse procedure with polarized array.In the first part,we discussed mathematical model of polarized array.A multi-channel fusion method is proposed based on the first polarized model.About the second polarized model,a space-polarization estimation method is probed by this section.A likelihood function is formed from statistical perspective.Furthermore,direction and polarized arguments are estimated by Newton’s method.