Derivative ESPRIT for DOA and polarization estimation for UCA using tangential individually-polarized dipole

Abstract The polarization-sensitive uniform circular array (P-UCA) is advocated for large airspace surveillance and polarization processing ability. To reduce antennas and get higher resolution ability than existing P-UCAs, we design a new configuration in which dipoles are arranged tangentially to circumference for diverse polarization responses, referred to as the tangential individually-polarized dipole UCA (TID-UCA). However, the diverse polarization responses hinder the design of fast parameter estimation algorithms and only searching class algorithms can be employed. Hence, we develop a direction of arrival (DOA) and polarization fast estimation algorithm named TID-UCA derivative ESPRIT. After analyzing the steering vector via the phase mode excitation theory, we carry out a virtual derivative transformation from the received data to get the additional data with the needed polarization responses. A set of weight is designed to make the weighted sum of the additional and received data have DOA and polarization decoupled. Based on that, DOA is obtained after solving a quadratic eigenvalue problem and polarization is solved through a corresponding plural equation. Moreover we derive asymptotic expressions of root mean squared errors and Cramer-Rao lower bounds of estimations. Extensive simulation results illustrate the enhanced resolution ability of the TID-UCA and our algorithm shows high accuracy of estimation with low computational complexity.