The Identification of Satellite Clock Noise Based on LAG1 Autocorrelation of Overlapping Samples

Abstract

Atomic clock is composed of various components of electronic devices, and its comprehensive effect of the internal and external environment makes it get easily affected by many kinds of noise. The random part of the clock bias is mainly influenced by the noise. The noise identification of atomic clock plays an important role in establishing an accurate random model and the weighting strategy of multi-GNSS. The most common methods for power-law noise identification are slope method, B1 partial factor method, LAG1 autocorrelation function method, and so on. However, these methods have their own defects or shortcomings. In this paper, we propose an improved method of LAG1 autocorrelation function based on overlapping samples to accurately identify the type of noise. By this method, we analyzed the main noise types affecting GPS and BDS satellite clocks. The results showed that the BDS satellite clock is mainly affected by White FM, Flicker FM and Random Walk FM. GPS BLOCK IIA Cs, BLOCK IIA Rb, BLOCK IIR Rb, BLOCK IIR M and BLOCK IIF Cs are mainly affected by the White FM and Flicker PM, and BLOCK IIF Rb is mainly influenced by the White PM, Flicker PM and White FM. The proposed new method based on overlapping sampling of LAG1 autocorrelation function can accurately identify GPS satellite clock noise, because the frequency bias and drift is more stable.