This research investigates the positioning performance of the L-band Digital Aeronautical Communications System (LDACS) and presents a system architecture based on carrier-smoothed ground-to-air pseudoranges (PR) along with clock corrections derived from Asymmetric Two-Way Time and Frequency Transfer (A-TWTFT) filters. The objective is to achieve required positioning accuracy and integrity for aviation operations, addressing the complexities associated with utilizing a terrestrial communications system for Complementary Positioning, Navigation, and Timing (CPNT). Through error covariance analysis, the study assesses the steady-state value, convergence time and bounding performances of the filters. The positioning performance highlights the benefits provided by the proposed architecture.