Improved moving scheme for coprime arrays in direction of arrival estimation

Coprime array motions are known to improve direction of arrival (DOA) estimation due to the synthetic aperture technique and the concept of difference coarray (DCA) are combined to achieve an increased number of degrees of freedom (DOFs). In this paper, an improved moving scheme for coprime array is presented, where the array spans a carefully designed large displacement. The benefit by doing this is that the overlapping lags induced by the original DCA and the shifted DCA can be avoided as much as possible, thereby significantly enhancing the number of consecutive DOFs (cDOFs). Then, the closed -form expressions of the displacement, cDOFs, and DOFs are derived. We also prove that the synthetic array has the same robustness against mutual coupling as the original array. It shows that the proposed moving scheme is more attractive than the other existing schemes. Finally, numerical examples are provided to demonstrate the superiority of the proposed moving scheme in both the absence and presence of mutual coupling.