Multisnapshot High-Resolution Gridless DOA Estimation for Uniform Circular Arrays

In this letter, we propose a multisnapshot gridless direction of arrival (DOA) estimation method for uniform circular arrays based on shift-invariant beam pattern. Firstly, the arbitrary shift-invariant beam pattern is expressed in Fourier series according to the Jacobi-Anger expansion, and the Fourier coefficients are obtained based on the directivity-maximization criterion. Then the weights of the beamformer are obtained and the beam power is calculated by the received snapshots. Subsequently, the DOA estimation problem is represented in the continuous angular domain using the Fourier expansion of the beam power. Finally, the gridless DOA estimates are obtained by atomic norm minimization. Simulation results demonstrate that the proposed low-complexity method improves the performance at low frequencies and low signal-to-noise ratio compared with other existing methods.