CARTA: Coordinated Arrangement of Receivers for Target Acquisition

The growing necessity for monitoring and identification of unmanned aerial systems (UASs) in restricted zones is paramount. Current strategies are inadequate for effectively tracking stealthy UASs, posing significant risks to both military and civilian domains. Although radar is renowned for its detection strength, its conventional active systems, where transmitters and receivers are co-located, encounter numerous challenges. A promising alternative is a passive radar, utilizing existing ambient signals, thus eliminating the need for a dedicated transmitter. In this context, we propose CARTA, a novel approach that utilizes spaceborne illuminators, particularly suited for tasks requiring extensive operational reach, such as high-altitude surveillance of missiles and fighter jets. Despite the chosen emitter type, challenges in range measurement and target localization persist, primarily due to the unknown position of transmitters. CARTA addresses this issue by adopting time difference of arrival (TDOA) techniques coupled with bistatic Doppler shift analysis. A critical, yet overlooked factor in passive radar systems is the impact of the geometric arrangement of receivers on localization accuracy. CARTA emphasizes the importance of optimizing receiver placement to minimize geometry-induced errors, recognizing the complexity of this NP-hard optimization problem. Our results indicate that CARTA significantly enhances localization accuracy compared to systems with arbitrary deployments.