Source Number Estimation for Iterative Coarray Beamforming with Partially Augmentable Arrays

In this paper, we present an iterative coarray domain beamforming algorithm with source number estimation for direction finding using partially augmentable sparse arrays, whose coarrays are non-uniform. Specifically, we employ a variant of the fast iterative interpolated beamforming (FIIB) that estimates the contributions of the missing coarray elements to emulate a uniform coarray. We exploit the deterministic nature of the noise in the coarray domain, together with its presence only at the central coarray element, to efficiently incorporate source number estimation in the FIIB algorithm. Using simulated data with a co-prime array, we demonstrate that the proposed algorithm is able to provide accurate estimates of the number of sources with high probability.