Bistatic Coprime MIMO Radar With Array Motions: Synthetic Sum-Difference Coarray Extension and Completion

In this paper, we consider the bistatic coprime MIMO radar in which the receive array is assembled on a movable platform and research the issue of jointly estimating the direction of departure (DOD) and direction of arrival (DOA). Specifically, we propose a dilated coprime array with nested motions (DCANM) that exploits the nested motions of the dilated coprime array to enlarge the virtual array in view of the synthetic sum-difference coarray (SDCA) concept. However, the holes in the synthetic SDCA of the bistatic coprime MIMO radar cause the performance loss of subspace-based coarray methods. To address this problem, we interpolate the holes of synthetic SDCA and propose a spatially smoothed interpolated coarray completion (SSICC) method to solve the rank deduction problem caused by the whole missing slices of SDCA, which helps to enhance the uniform DOFs and identifiability. Finally, extensive simulation results are carried out to demonstrate the superiorities of the proposed methods in estimation accuracy and resolution.