Progression of clock DBD changes over time

• Published in: Metrology and Measurement systems Vol. 30; no. 3; pp. 499 - 505
• Main Authors: Maciuk, Kamil, Varna, Inese, Kudrys, Jacek
• Format: Journal Article
• Language: English
• Published: Warsaw Polish Academy of Sciences 01.01.2023
• Subjects: clock; Data analysis; Data processing; dbd; Global navigation satellite system; gps; jump; Noise measurement; outlier; Outliers (statistics); reference clock; satellite; Satellite orbits; Satellites
• ISSN: 2080-9050; 2300-1941
• DOI: 10.24425/mms.2023.146414

Day-boundary discontinuity (DBD) is an effect present in precise GNSS satellite orbit and clock products originating from the method used for orbit and clock determination. The non-Gaussian measurement noise and data processing in 24 h batches are responsible for DBDs. In the case of the clock product, DBD is a time jump in the boundary epochs of two adjacent batches of processed data and its magnitude might reach a couple of ns. This article presents the four GNSS (Global Navigation Satellite System) systems DBD analysis in terms of change over an 8 year period. For each of 118 satellites available in this period, the yearly value of DBD was subject to analysis including standard deviation and frequency of outliers. Results show that the smallest DBDs appear in the GPS system, the biggest – for the BeiDou space segment. Moreover, the phenomenon of changes in DBDs over time is clearly seen at the beginning of the analysed period when the magnitude and number of the DBDs were larger than for current, newest clock products