Efficient DOA estimation method employing unitary improved polynomial rooting

High resolution direction-of-arrival (DOA) estimation is one of the most challenging problems in array signal processing. In this paper, a variation of the improved polynomial rooting (IPR) method is proposed for DOA estimation of multiple targets by a sensor array. The variation, unitary IPR (UIPR), transforms the complex-valued covariance matrix of the sensor signals to a real-valued matrix using unitary transformations. Then the IPR method is applied to determine the DOA of the targets. Simulation results indicate the potential improvement provided by our approach compared with MUSIC, Root-MUSIC, ESPRIT, and IPR.