Coarray beamspace transformation based DOA estimation for uniform circular arrays

The beamspace transformation (BT) is utilized to convert a uniform circular array (UCA-BT) to a virtual uniform linear array (VULA) for spatial smoothing and direction-of-arrival (DOA) estimation. The estimation performance of the UCA-BT is significantly affected by the choice of phase mode order. In order to enhance estimation performance, we propose a new coarray beamspace transformation (CBT) algorithm based on the UCA in this paper. The difference coarray of a UCA, which is a uniform concentric circular array (UCCA), is first calculated using the covariance vectorization technique. Subsequently, the BT is applied to the UCCA coarray to obtain a large VULA. The forward spatial smoothing and MUSIC algorithms are then implemented to the VULA for high-resolution DOA estimation. Simulation results demonstrate the effectiveness of UCA-CBT algorithm compared to other estimation methods.