Dottorato in INGEGNERIA AERONAUTICA E SPAZIALE

Titolo della tesi: Time - Frequency Transfer and Orbit Determination Systems for Space Applications

Precision time and frequency transfer underpins modern scientific and technological advancements, enabling applications in navigation, metrology, and fundamental physics. The evolution of atomic clocks, alongside advancements in radiometric tracking techniques, has led to increasingly accurate synchronization while improving the stability and miniaturization of space clocks for high-precision scientific experiments. This dissertation investigates time and frequency transfer techniques to address challenges in satellite navigation, timekeeping, and fundamental physics. Precise synchronization is essential for orbit determination, time dissemination, and robust global positioning systems. In metrology, clock comparisons over radio links support the dissemination of accurate time standards, impacting financial markets, scientific observatories, and global infrastructures. In fundamental physics, space-based atomic clocks enable tests of relativistic effects and searches for variations in fundamental constants. Drawing on GNSS and TWSTFT methodologies, this work develops novel approaches to synchronization in these fields, with a focus on overcoming propagation media effects, link asymmetries, and station biases. Additionally, integrated orbit determination and time synchronization (ODTS) algorithms are explored to decouple clock and spacecraft dynamics, in the context of deep-space navigation. The findings of this research contribute to the refinement of time transfer techniques for next-generation space missions, ultra-precise timing applications, and future optical clock networks. The results support the transition toward a more robust and accurate global timekeeping infrastructure, ensuring the traceability and accessibility of precision time standards for emerging scientific and technological frontiers.