The analysis of two-way time transfer precision caused by shiping

The precision time synchronization is of great significance for aerospace, digital communications and deep space exploration etc. The synchronous frequency and time of different node devices are very critical when multi-systems are highly coordinated. Due to the signal propagation path is approximately symmetrical in two-way time transfer(TWTT), The effect of path delay error to a great extent have been offset, so the time synchronous precision is improved. This method got the attention of time transfer research department every countries. The principle and system composition of TWTT are described. The factors influencing the time synchronous precision are deduced through analysis of signal transfer link. It includes time-interval measurement error, system error of the equipment, signal propagation delay error in air, and delay error caused by shippig et. Delay errors caused by shippig is analyzed in detail. Delay error mathematical model caused by shippig is set up. Using the second-order expansion Taylor, the delay error caused by movement velocity and acceleration of ships are deduced. The delay error caused by shippig of TWTT is below 0.1ns through theoretical analysis and calculation.