Parameter estimation using antenna arrays of directional sensors

An antenna array made of non-isotropic sensors is used to estimate the parameters of an emitting source. The estimation accuracy depends on the radiation pattern of the individual sensor, and so, in a non-trivial manner. Estimation performance is evaluated in terms of the Cramer-Rao bound for which an analytical expression is found and compared to the classic case of antenna arrays of isotropic sensors. A gain function is introduced that expresses the benefit from using directional sensors. It is interpreted to derive a certain number of general conclusions, independently from the actual sensors, algorithms or array configurations.