Directive antenna arrays for 3D source localization

Circular antenna arrays are widely used in positioning systems. Due to their geometry, they are able to provide an equal localization accuracy regardless of the target location. We address those applications for which this is not required. By choosing alternative arrays, it is shown that localization performance can be significantly enhanced, compared to the case of circular antennas, over an arbitrary large sector. The design of the so-called directive antenna arrays is based on a simplified Cramer-Rao bound associated with the estimation of the direction(s) of arrival of a source located in the far field of the antenna array. The simplified bound gives an interesting insight into the behavior of the localization algorithm w.r.t. the location of the source. Based on the simplified bound, a design criterion for directive antenna arrays is proposed, then applied to develop a class of Y-shaped antenna arrays.