High Precision Clock Bias Prediction Model in Clock Synchronization System

Abstract

Time synchronization is a fundamental requirement for many services provided by a distributed system. Clock calibration through the time signal is the usual way to realize the synchronization among the clocks used in the distributed system. The interference to time signal transmission or equipment failures may bring about failure to synchronize the time. To solve this problem, a clock bias prediction module is paralleled in the clock calibration system. And for improving the precision of clock bias prediction, the firstorder grey model with one variable (GM(1, 1)) model is proposed. In the traditional GM(1, 1) model, the combination of parameters determined by least squares criterion is not optimal; therefore, the particle swarm optimization (PSO) is used to optimize GM(1, 1) model. At the same time, in order to avoid PSO getting stuck at local optimization and improve its efficiency, the mechanisms that double subgroups and nonlinear decreasing inertia weight are proposed. In order to test the precision of the improved model, we design clock calibration experiments, where time signal is transferred via radio and wired channel, respectively. The improved model is built on the basis of clock bias acquired in the experiments. The results show that the improved model is superior to other models both in precision and in stability. The precision of improved model increased by 66.4%∼76.7%.

The comparison model of satellite-earth time based on special relativity and its accuracy analysis

“…The delay of Atomic clock [3] The delay of Photoelectric modulation [4] The delay of Optical fiber dispersion [5] The delay of The troposphere [6] The delay of Ionospheric layer [7] The delay of Sagnac effect [8] The delay of Theory of relativity [9] The delay of temperature [10] 10E-11s In the existing satellite-earth time comparison model of special relativity, researchers discuss all the delay in the process of satellite-earth time comparison, which are arranged in downlink order according to the order of delay, as shown in Table 1.…”

Research on Passive Troposcatter Location System

“…However, dividing confusion area with the same width lacks generality. Meanwhile, time synchronization is the prerequisite of coordinating distributed system operations [26]. During operating the passive system, time synchronization with high precision must be got and kept.…”

Theoretical Model of an Experiment to Test the Isotropy of the Speed of Light

“…Determining the OWSL has been studied considerably in the past. Michelson-Morley experiment and Kennedy-Thorndike experiment [8] have shown that the TWSL is independent of the closed path considered, and is isotropic. Although the average speed of TWSL can be measured, the OWSL is still undefined.…”