ABSTRACT
This chapter (see also [1,2]) considers new methods for multiple electromagnetic source localization using sensors whose output is a ‘‘vector’’ corresponding to the complete electric and magnetic fields at the sensor. These sensors, which will be called ‘‘vector sensors,’’ can consist, for example, of two orthogonal triads of scalar sensors that measure the electric and magnetic field components. Our approach is in contrast to other chapters that employ sensor arrays in which the output of each sensor is a scalar corresponding, for example, to a scalar function of the electric field. The main advantage of the vector sensors is that they make use of all available electromagnetic information and hence should outperform the scalar sensor arrays in accuracy of direction of arrival (DOA) estimation. Vector sensors should also allow the use of smaller array apertures while improving performance. (Note that we use the term ‘‘vector sensor’’ for a device that measures a complete physical vector quantity.)
Section 6.2 derives the measurement model. The electromagnetic sources considered can originate from two types of transmissions: (1) single signal transmission (SST), in which a single signal message is
transmitted, and (2) dual signal transmission (DST), in which two separate signal messages are transmitted simultaneously (from the same source), see for example [3,4]. The interest in DST is due to the fact that it makes full use of the two spatial degrees of freedom present in a transverse electromagnetic plane wave. This is particularly important in the wake of increasing demand for economical spectrum usage by existing and emerging modern communication technologies.
