High-precision Laser Time Transfer Technology

In this dissertation, the high-precision time transfer by laser pulses is discussed in detail. The main contents are divided into seven chapters.Chapter 1 is the introduction. Chapter 2 and 3 provide the primary concept and mathematical expressions for the time transfer by laser pulse in two aspects. One is time and frequency theory, the other is satellite laser ranging theory. The expression about accuracy, drift and stability of clock frequency are presented here. Additionally, the Lidar link equation is also presented. In Chapter 4 the history and progress of time transfer by laser pulses are described. As we know, it played the important role in the field of time and frequency as well as relativity field. Early in 1905, A.Einstein stated the idea about comparing separated clocks by light pulse for testing the special relativity theory in time and space.Chapter 5 and 6 are the core part of this dissertation. Starting from the principle of time transfer by laser link, the necessary equipment for one practical system is introduced. The error equation and correction due to relativity effect in the time comparison between satellite and ground clocks are deduced. An experimental system for determining local time differences and relative frequency difference for two separate hydrogen masers has been carried out. It is shown in the preliminary results that, the standard deviation of the mean of the clock differences is 24.1ps for a 100s interval, the relative frequency difference for two masers is 5.8×10-13. The relative stability of frequency for two masers is 1.8×10-13/200s.The future plan is put forward in chapter 7. That is, on the basis of the local experiment , to develope time transfer technique by laser link between a ground clock and a space one or between two remote ground clocks.