Research On Satellite Timing Method And Time Synchronization Data Processing Technology Between Satellite And The Earth

High-precision time synchronization has important significance in national economic construction, national defense, space exploration, and other aspects. In the global navigation and positioning system, GPS has a high stability and high accuracy atomic frequency standard, and can provide time service the whole world entire day. However, the signal spread on the speed of light, a nanosecond of error can lead to a deviation of 30 centimeters. So high-precision time synchronization is a prerequisite for accurate positioning. This paper is based on how to improve the timing synchronization precision.Time standards of GPS system was described in the paper first, and then the principle of positioning and time service of the system were introduced. The main error in the process of timing was studied, including ephemeris error, satellite clock error, relativistic effects, the ionosphere error, troposphere error, the antenna phase center error, and so on. Some revision methods for these errors have been discussed. Describes three kinds of timing synchronization method which were commonly used currently: one-way timing synchronization, two-way timing synchronization and laser-timing synchronization. Analyzed the advantages and disadvantages of these three methods. Chose the one-way timing synchronization method for the basic of the study. A specific program for timing and simulation results were given, and the timing accuracy is analyzed.Time difference data processing is another emphasis of this paper. Moving average, Kalman filtering and wavelet transform were selected to analyze and process the time difference data from a base station. Comparing the advantages and disadvantages of these three methods from the principles of denoising and the specific simulation results, Moving average has simple model and good real time character but low precision; Kalman filtering need the system model beforehand, so has localization in real use. Wavelet transform method was ultimately chosen, sym6 wavelet function was selected, using soft-threshold method, with the decomposition scale of five-layer. The frequency offset of the cesium atomic clock can be got from the processed curve, which will compensate for the clock. Simulation shows that the compensated clock error data achieves a higher accuracy.