Minimizing the Cramer-Rao Lower Bound for Antenna Arrays with Directional Radiators for Direction-of-Arrival Estimation of Radio Signals

The paper describes an approach reducing errors in estimating the direction-of-arrival of signals by antenna arrays. In particular, the lower Cramer-Rao bound (LCRB) is used for the task. This quantity sets the limit below which one or another direction-of-arrival estimation algorithm cannot fall for particular antenna array geometry. The derivation of a formula based on the Cramer-Rao lower bound is given, which describes the dependence of errors on the location of antenna elements in the Cartesian coordinate system. In this case, it is considered that the antenna element directive factor exceeds one. The proposed technique is based on the minimization of LCRB by the optimal placing of the antenna elements. The antenna array forms obtained in this way make it possible increasing the accuracy direction-of-arrival estimation algorithms.