Noncircular Signal-based Sparse Array Design And DOA Estimation

The direction of arrival(DOA)estimation is an important branch of array signal processing,which is widely used in radar,sonar,communication,and other related fields.Compared with the uniform array,the sparse array has more virtual lags,higher degrees of freedom,and a weaker mutual coupling effect,which greatly improves the estimation performance,and thus becomes a research hotspot in the signal processing field in recent years.Compared with circular signals,non-circular signals need to be expanded to process the accepted signal when performing DOA estimation,which increases the amount of computation but also doubles the available information.In this paper,a sparse array under non-circular signals is taken as the research object,and a design method of the sparse array with high degrees of freedom is proposed by combining difference and sum coarray with the property that the pseudo covariance is not zero.The main work includes:For the minimum redundant coprime array,based on non-circular signals,the mathematical expressions of the hole positions,maximum consecutive lags and unique lags are analyzed by combining difference and sum coarray.Taking maximum consecutive lags as the optimization objective,an optimal configuration method for minimum redundancy coprime arrays is proposed.Theoretical analysis and simulation experiments verify the superiority of the proposed method.A shifted non-hole sparse array(SNHSA)is proposed.By analyzing the virtual redundancy position of the nested array and shifting some sensors in its dense subarray,a new sparse array SNHSA is formed,and its mathematical expression for consecutive lags is derived.Theoretical analysis and simulation experiments demonstrate the advantages of the proposed method.A shift-split sparse array(SSSA)is proposed.In order to solve the problem of lags redundancy of dense subarrays in SNHSA,a new sparse array SSSA is designed by splitting and shifting some sensors in dense subarrays.For a given number of sensors,SSSA can obtain more consecutive lags than SNHSA.The mathematical expressions of consecutive lags and hole positions for SSSA are derived.Theoretical analysis and simulation experiments prove the advantages of the proposed method.