Estimation of the direction-of-arrival of incoming EM wavefronts through a neural network approach

Many direction finding methods have been designed over the years since the early works of Ettore Bellini and Alessandro Tosi [1], depending on the up-to-date available technologies and frequency band of interest. This latter aspect is strictly related to the physical dimensions of the overall antenna system, possibly limiting the maximum number of antennas as well as their radiation characteristics (omnidirectional, semi-directive, directive). In the present case of interest, the focus is at applications in the HF, VHF and UHF frequency bands where the correlative as well as the Wattson-Watt techniques (see [2]) are used the most to estimate the angle (or direction) of arrival of an unknown impinging wave-front. In addition, they generally rely on omnidirectional radiating elements due to their inherent physical large size at such frequencies.