Relativistic Modelling for Highly Precise Ranging and Time Transfer via Optical Inter-Satellite Links

Very accurate time synchronization is a fundamental requirement for satellite navigation systems. Recent improvements in clock technology enable more stable time generation and finer timing capabilities. This entails stricter demands on the modelling of timescales. The German Aerospace Center is evaluating the use of optical clocks for a future Global Navigation Satellite System. The system consists of a constellation of satellites carrying such type of clocks and equipped with optical terminals allowing for the exchange of information. Optical links can be used for precise synchronization and ranging. In this work time transfer schemes based on the exchange of time stamps via optical signals are proposed and relativistic models capable of enabling picosecond level synchronization are derived.