A Hybrid Self-Tracking Receiver Implementation with Direction-of-Arrival Estimation for Retro-Directive Antenna Systems

Self-tracking receivers have been suggested for satellite and mobile communication applications. In this paper, we propose and demonstrate an array receiver (Rx) architecture based on phase-locked loops. The system is capable of automatically tracking a moving source and providing direction-of-arrival (DOA) estimates calculated from array signal phase differences. After deriving the system transfer functions, we show a digital implementation of the receiver and experimentally prove its phase detection capability. In combination with an eight-element linear array and analog front ends, we build a hybrid receiver and demonstrate its DOA estimation performance in static and dynamic outdoor setups. This paper gives the details about theoretic principles, implementation concept, and realization of the proposed receiver. We demonstrate DOA errors below 4° and show the reproducibility of the results. Using dynamic experiments, we verify the tracking ability of the system, which makes it applicable to retrodirective antennas.