Accurate Time Transfers in Crosslink / Communications Networks

Systems & Technology Research (STR) is proposing to advance the STR Loop-Inclusive Graphical Hierarchical Time Transfer (STR-LIGHTT, pronounced “starlightâ€Â) algorithm for synchronization of the GPS space vehicle (SV) constellation via crosslinks. STR-LIGHTT simulations show order of magnitude improvement in SV clock performance down to 100-ps synchronization. STR will extend its algorithm for GPS synchronization via proliferated LEO (P-LEO) constellations by incorporating ad hoc network techniques into STR-LIGHTT. Both the original and ad hoc versions of STR-LIGHTT will be demonstrated in software-defined radios (SDRs) and tested for fault tolerance and algorithmic vulnerabilities to ensure successful transition to operational systems. A P-LEO payload for GPS synchronization will be designed to further aid STR-LIGHTT deployment. Successful implementation of STR-LIGHTT will enable higher precision timing in the GPS and other constellations for better positioning performance in the case of GPS and more advanced distributed sensing applications in general.