An efficient vector sensor configuration for source localization

An electromagnetic vector-sensor enables estimation of the direction of arrival (DOA) and polarization of an incident electromagnetic wave with arbitrary polarization. In this letter, an efficient vector-sensor configuration is proposed. This configuration includes the minimal number of sensors, which enables DOA estimation of an arbitrary polarized signal from any direction except two opposite directions on the z-axis. The configuration is obtained by analyzing the Cramer-Rao lower bound (CRLB) for source localization using a single vector-sensor. The resulting vector-sensor configuration consists of two electric and two magnetic sensors. It is shown that this quadrature configuration satisfies the necessary and sufficient conditions for the DOA estimation problem. The CRLB for DOA estimation of signals in the azimuth plane is identical for the quadrature and the complete vector-sensor configurations.

I. Introduction

IN THE LAST DECADE, many array processing techniques for source localization and polarization estimation using vector sensors have been developed. Nehorai and Paldi [1] developed the Cramer-Rao Lower bound (CRLB) for this problem and the vector cross-product direction-of-arrival (DOA) estimator. Identifiability and uniqueness issues associated with vector sensors are analyzed in [2]–[6]. Eigenstructure-based source localization techniques, such as ESPRIT and MUSIC using vector sensor arrays have been extensively investigated. Li [7], [8] applied the ESPRIT algorithm to a vector sensor array. ESPRIT-based direction finding algorithms using vector sensor arrays have been further investigated in several papers [9] [10]–[12]. MUSIC-based algorithms for this problem have been applied in [13], [14]. Coherent source localization algorithms are developed in [15].