Research On Traceability Link Of A Navigation System And The Method Of Its Uncertainty Analysis

In the field of metrology, the quantitative expression of the measurement uncertainty, an important concept, is widely used. As the international unit has been used in all kinds of science and technology all over the word, no matter what kind of measurements needs to use measurement uncertainty.In the satellite navigation system, it is great significant that assessment the performance of time traceability link is an important part of navigation. Currently, the measurement uncertainty is applied to estimate time comparison link in the time and frequency measurement and comparison field. In this paper, the uncertainty of GNSS common view comparison link is analyzed and the uncertainty of a navigation system GNSS time traceability link is studied.According to the feature of GNSS common view comparison link, the fragment analysis method of uncertainty about comparison link which providing a theoretical basis to analysis the uncertainty and a reference to estimate the performance of time link, is demonstated. The main research contents of this paper:(1) In detail, the principle of international time comparison link are presented, such as TWSTFT, optical fiber, and GNSS CV. Meanwhile, the concept and evaluation method of measurement uncertainty are introduced.(2) According to the feature of time comparison link, the fragment analysis method of uncertainty about comparison link is presented. Additionally, the analysis method of type A and B uncertainty of time link is introduced, and the uncertainty of the various errors in the time transfer process is analyzed.(3)The uncertainty of time link is estimated based on the transmit system.The overall design of navigation system,and the data processing method of GNSS CV are discussed. Using the measured data analyzes time traceability link of the navigation system. For type A, RMS of GNSS CV link with respect to optical fiber link are calculated. Besides, Type A is evaluated with calculating standard deviation after deduction system errors. Meanwhile, Type A is evaluated with calculating time deviation. Type B is analyzed from time transfer process.(4)The result of type A and B uncertainty are analyzed. Meanwhile the combined standard uncertainty and expanded uncertainty are evaluated.