Time and Frequency Transfer using Passive Techniques in Active Fiber Optic Networks

For the modern society, high precision time and frequency transfer have become crucial since a large number of systems, such as telecommunication systems, require precise and stable synchronization. Electric power companies use synchronized systems for taking stability measurements and searching for errors in their networks. For the scientist working in radio astronomy with very long baselines interferometer (VLBI), synchronization and timing are important factors and as a result, many laboratories operates their own timescales with atomic clocks as reference. Navigation of spacecrafts within the solar system is heavily dependent on synchronized control stations on Earth. The financial market uses time and date stamps for identification of transactions in order to organize them in chronological order to increase electronic transaction speed. There are many more areas within the society that are in need of time and frequency synchronization with varying accuracy and precision. Many of these applications utilize GNSS (Global Navigation Satellite System) for these purposes of time and frequency synchronization. GNSS depends on radio transmissions that easily can be disrupted; therefore, the main objective for this thesis is to implement a system within Sweden for high precision time transfer utilizing existing infrastructure for an alternative and complementary time transfer method, with comparable accuracy and stability to existing and well established satellite based methods. An introduction to the developed technique for passive time transfer with its benefits is presented in the thesis, and is further described with its different sources of error in papers [A-D]. Precision relative to the GPS (Global Positioning System) carrier phase o