Performance analysis of passive low-grazing-angle source localization in maritime environments using vector sensors

We consider the problem of passive estimation of source direction-of-arrival (DOA) and range using polarization-sensitive sensor arrays, when the receiver array and signal source are near the sea surface. The scenario of interest is the case of low-grazing-angle (LGA) propagation in maritime environments. We present a general polarimetric signal model that takes into account the interference of the direct field with the field reflected from smooth and rough surfaces. Using the Cramer-Rao bound (CRB) and mean-square angular error (MSAE) bound, we analyze the performance of different array configurations, which include an electromagnetic vector sensor (EMVS), a distributed electromagnetic component array (DEMCA), and a distributed electric dipole array (DEDA). By computing these bounds, we show significant advantages in using the proposed diversely polarized arrays compared with the conventional scalar-sensor arrays.