The Prototype Co-Prime Array with a Robust Difference Co-Array

In this paper, we present a new sparse co-prime array design that achieves a higher number of degrees-of-freedom for direction-of-arrival (DOA) estimation. The proposed array design adopts a sequence of displacements applied in a systematic procedure to the sensors of one of the two constituent sub-arrays of the prototype co-prime array. Accordingly, the applied displacements completely eliminate the redundant virtual sensors between the two sub-arrays and at the same time considerably increase their number of uniform DOFs. Moreover, with no cross-sensor redundancies, the new design is of ideal first weight functions, and hence, it resolves sources more robustly than other co-prime array designs in the presence of mutual coupling. Simulation results demonstrate the superior performance of the proposed co-prime structure.