Sparse nested array with aperture extension for high accuracy angle estimation.

• A two-level sparse nested array configuration is proposed for aperture extension to realize the highly accurate angle estimation. • By exploiting the proposed SNA, an ESPRIT-based algorithm is developed to extract two sets of angle estimates: a set of coarse estimates and a set of fine but ambiguous estimates. Fine and unique angle estimates are then obtained by a simple refine step. • The SNA concept herein proposed may also be applied to other types of nonuniform arrays for highly accurate angle estimation with increased degrees-of-freedom. Sparse nested arrays (SNAs) are presented for highly accurate angle estimation. A nested array is sparse if its sensor-spacing of the first level is extended beyond a half-wavelength. Each array grid is equipped with an identical two-component subarray, such as a half-wavelength spaced doublet, a spatially-colocated p-u probe and a spatially-orthogonal dipole/loop pair, to solve angle ambiguities caused by aperture extension. [ABSTRACT FROM AUTHOR]