Using Sign Patterns to Distinguish Feared Clock Events

Matthias Suess and Ulrich Grunert

Abstract:	The first and second difference of clock measurements is investigated to detect and identify clock events. A hypothesis test of the difference functions is described which is calibrated by given Allan deviations of the observed clock differences. The impact of four defined clock events, namely time step, frequency step, drift step, and outlier on the first and second differences is calculated. The analysis outlines that the sign of these calculations generate a pattern of “1”, ”0”, and “-1”, which are called event patterns. In order to identify the underlying event type, the identification method interprets the detection process again as a sequence of “1”, “0”, and “-1” and maps the event patterns to the detection patterns. The detection and identification method are assessed by analyzing the time offset measurements between a commercial rubidium frequency standard and an active hydrogen maser. Both clocks are operated at the DLR timing laboratory.
Published in:	Proceedings of the 40th Annual Precise Time and Time Interval Systems and Applications Meeting December 1 - 4, 2008 Hyatt Regency Reston Town Center Reston, Virginia
Pages:	287 - 300
Cite this article:	Suess, Matthias, Grunert, Ulrich, "Using Sign Patterns to Distinguish Feared Clock Events," Proceedings of the 40th Annual Precise Time and Time Interval Systems and Applications Meeting, Reston, Virginia, December 2008, pp. 287-300.
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