An efficient single receiver high resolution DOA estimation algorithm for modulated signals

Direction finding techniques can be applied to a number of military and civilian systems, such as radar, sonar, and radio communications. It aims at finding the Direction of Arrival of an electromagnetic source for positioning purposes. Direction finding systems can be primarily classified as multiple or single channel. The single-channel solution, investigated herein, is based on a switched antenna associated to a special Phase Locked Loop (PLL) receiver architecture that allows tracking the phase of each antenna. The PLL output is processed by a signal processing block that removes the ambiguity inherent to the PLL and estimates the angle of arrival of the source. This procedure is usually linked to high computational complexity that increases with the number of antennas and with the modulation level. This article proposes a technique to decrease the computational burden of the PLL-based single receiver DOA estimation scheme and to use the super resolution algorithm Multiple Emitter Location and Signal Parameter Estimation to obtain azimuth and zenith angles with improved accuracy. The simulated results using the novel algorithm are shown and its performance compared to the traditional solution in different scenarios.