Research On DOA Estimation Algorithm Based On Coprime Array Virtual Hole Filling

In the research of various array technologies,due to the many advantages of the coprime array,such as large aperture and high degree of freedom,it has become an important research topic in the field of DO A estimation.A coprime array uses a small number of array elements,and the spacing between array elements is not limited.It can expand a large number of virtual array elements.The virtual array elements can increase the degree of freedom of the array,which can effectively solve when the number of signals is greater than the number of physical array elements DOA estimation problem.Generally,in most of the expanded virtual array elements,only the continuous elements are used.There is a "hole" between the continuous virtual array element and other virtual array elements.The virtual array element response caused by the lack of the hole position results in the subsequent The virtual array element is not available.In order to improve the utilization of virtual array elements,this paper conducts research on the filling of holes in virtual arrays.The main contents are as follows:(1)The mathematical model of uniform array and its two classic DOA estimation algorithms are introduced.For coherent signal sources,the forward-backward smoothing algorithm and the ESPRIT algorithm based on Toeplitz matrix reconstruction are studied.(2)The original coprime array and the improved second-order extended coprime array are analyzed.Based on the array structure of the improved second-order extended coprime array,the array receiving data model and the construction principle of the virtual array are introduced.The degree of freedom of the array in the virtual array element is analyzed.For a single hole,the method of using the array element responses of two virtual array elements next to the hole to fit the virtual array element response of the hole position to fill the hole is studied.After filling the holes,the utilization rate of the virtual array elements is improved,and the DOA estimation research is performed in conjunction with the SS-MUSIC algorithm.Through simulation experiments,the three methods of original array,improved second-order extended array and virtual array cavity filling were compared and analyzed.(3)In order to further improve the utilization of virtual array elements,a DOA estimation method based on complementary coprime arrays is proposed.This method first determines the position of the holes in the virtual array,and finds the largest continuous hole behind the position according to the distribution pattern of the holes.An additional sub-array is added to the position of the coprime array corresponding to the virtual hole.Increasing the original length of the array as a whole,and adding sub-arrays can fill all the holes in the virtual array,making the utilization rate of the virtual array 100%.At the same time,the ESPRIT algorithm based on complementary coprime arrays was studied,and the performance improvement of complementary coprime arrays in degrees of freedom,angular resolution and accuracy was verified through simulation experiments.