Research On Multi-target Direction Finding Technology For Digital Radar

Multi-target direction finding,as one of the most important branches in the field of array signal processing,has always been a research hotspot in recent years.It is impossible to deal with all direction finding scenarios by one algorithm alone as the signal sources are in different forms due to the complexity and variety of the actual application scenario environment.This paper focuses on the multi-target direction finding algorithms for wideband signals and narrowband signals with the signals are coherent or not.The main work and research contents include the following:1.The wideband and narrowband signal model and the concept of correlation are introduced,then the receiving signal on uniform linear array is given.2.For non-coherent narrowband signals,a classical multi-target direction finding algorithm is first introduced,then its improved version is also given.For coherent narrowband signals,three different algorithms are discussed,and the performance of the mentioned algorithms is compared by simulation studies and analysis.3.For wideband signals,the narrowband signal multi-target direction finding algorithm above is no longer applicable.The traditional way to process wideband signal is using the frequency domain structure algorithm based on Fourier transform.This paper first introduces the most classical Incoherent Signal Subspace Method in broadband,then bring the idea of focusing to introduce the coherent broadband multi-target direction finding Coherent Signal Subspace Method and the Focused Test of Orthogonality of Projected Subspaces algorithm,then compare the performance,advantages and disadvantages of mentioned algorithms above through simulation.4.As the complexity of traditional frequency domain structure processing,it needs a lot of calculations and large amount of data,and there's only a few amount of researches on broadband multi-target direction finding under other structures.This paper research on broadband multi-target direction finding based on time domain.Firstly,introduces a newly algorithm based on time domain The Steered Effective Projection,based on this,proposes a without pre-delay incoherent signal algorithm based on time domain,verified its correction and compared with the traditional frequency domain structure and The Steered Effective Projection algorithm by simulation,it proves that the algorithm proposed in this paper has better performance.Then based on above and the idea of the iterative adaptive approach,a multi-target direction finding algorithm for coherent signals is proposed.The simulation also proves the effectiveness of the algorithm and it has better performance.