Closed-form 2D angle estimation with a spherical array via spherical phase mode excitation and ESPRIT

We present a new spherical ESPRIT algorithm, being a closed-form algorithm for use in conjunction with spherical arrays that provides automatically paired source azimuth and elevation estimates. It is a numerically efficient 2D angle-of-arrival estimation algorithm which does not rely on extensive spectral searches or iterative solutions to multi-dimensional optimization problems. The spherical ESPRIT is based on the spherical phase mode excitation principle, enabling us to exploit the spherical symmetry of the antenna array by relying on a recursive relationship between spherical harmonics.