Design And Analysis of the Sparse Array for DoA Estimation of Noncircular Signals

Recently, many sparse arrays have been proposed to increase the number of degrees of freedom for direction of arrival (DoA) estimation especially for circular signals. Though many practical signals are noncircular, still the properties of noncircularity are hardly exploited in the design of sparse linear arrays. A new array geometry for noncircular signals, which significantly increases the aperture of the virtual array, has been proposed in this paper. The structure is obtained by systematically placing the two uniform linear array (ULA) side by side. The proposed design provides the largest aperture virtual ULA (VULA) as compared to the existing array structures. The aperture of VULA and corresponding weight function are evaluated analytically. The closed-form expression of the Cramèr–Rao bound, the minimum lower bound on the error in the DoA estimation, is also obtained for the proposed structure. The performance of the proposed array is studied by the exhaustive computer simulations.