Fast four-dimensional joint spectral estimation with array composed of diversely polarized elements

This article presents a fast algorithm for joint spectral estimation of the two-dimensional (2-D) angles and polarization of the impinging signals. The algorithm utilizes the continuity property of the signal polarization. By detecting the polarization state of some location in the space, the polarization state of the adjacent position can be limited into a small area and calculated at a small expense. In this way, we can take the advantage of the joint spectral estimation without enormous calculation invoked in the 4-D search.