Fiber-based Time And Frequency Synchronizaiton Network And Aerospace Measurement Application

Fiber-based time and frequency synchronization technology can realize highprecision time and frequency synchronization, and show great potential applications in optical atomic clocks comparison, astronomical observation, deep space exploration, and many other areas. The research content of this thesis is aimed at overcoming the limitation of applying areas in traditional fiber-based time and frequency synchronization schemes.We propose and demonstrate a variety of new synchronization schemes for fiber networks and introduce their applications in the field of aerospace measurement.A fiber-based multiple-access ultrastable frequency dissemination scheme for both radio frequency modulated on the optical carrier and optical frequency is introduced. Relative frequency stabilities of 7×10-14/s and 5 × 10-18/day for radio frequency, 3 × 1016/s and 4 × 10-18/104 s for optical frequency have been obtained, respectively. Using this method, highly synchronized radio-frequency modulation signal or the optical signal itself can be regenerated along the entire fiber link and it is expected to have potential applications, especially in long-distance synchronous situations.This thesis also introduce the a newly proposed fiber-based RF dissemination scheme suitable for a branching network. Using the passive phase noise cancelation method, the highly stable reference frequency signal can be delivered to remote sites simultaneously and independently. For 10 km distance dissemination, relative frequency stabilities of6 × 10-15/s and 7 × 10-17/104 s are obtained. The scheme can dramatically simplify the set-up and reduce cost. These advantages make it suitable for constructing the frequency synchronization networks for DSN and SKA.As a potential application example,the Beijing regional time and frequency synchronization network under construction is also briefly introduced.As a key content, this thesis also introduce the connected element interferometry(CEI) experiments, using the fiber-based frequency synchronization technology, combined with the clock transportation timing comparison method, high precision time and frequency synchronization between two stations 70 km apart from each other has been realized, relative frequency stability of 5 × 10-15/s and 6 × 10-19/104 s, timing accuracy better than 5 ns are achieved. Based on the preliminary analysis of the satellite data,orbit determination precision at meter level can be estimated theoretically. Preliminary experimental results show that, the usage the fiber-based synchronization technology can greatly improve the time and frequency precision in VLBI measurements, so as to shorten the observation base and improve the observation precision.