Direction-of-arrival estimation using an ESPRIT array with double invariance

We present a new non-iterative method called Weighted Subspace Estimation (WSE) for estimating directions-of-arrival (DOA´s) of narrow band plane waves impinging on an ESPRIT array with double invariance. WSE uses the first invariance to get a subspace estimate; the estimates of DOA´s are then extracted from the estimated subspace by exploiting the second invariance. Simulations show that, the performance of WSE achieves or is very close to the Cramer-Rao bound in a wide range of SNRs and signal correlation