2D DOA Estimation Through a Spiral Array Without the Source Number

In this paper, a spiral array is designed to estimate two-dimensional direction of arrival (DOA), which allows a larger spacing between adjacent antennas of the array. The fourth-order cumulant is also utilized to create more virtual antennas, further enlarging the array aperture. The noise resistance of the high-order cumulant can help to construct an improved propagator, and there is no need for any priori knowledge of the source number to estimate the DOAs. With the help of the cumulant, a convex optimization is introduced to improve the estimation accuracy, which can overcome the estimation bias caused by the finite snapshots. Simulation results demonstrate the effectiveness of the proposed estimator.