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Metafitting: Weight optimization for least-squares fitting of PTTI dataFor precise time intercomparisons between a master frequency standard and a slave time scale, we have found it useful to quantitatively compare different fitting strategies by examining the standard uncertainty in time or average frequency. It is particularly useful when designing procedures which use intermittent intercomparisons, with some parameterized fit used to interpolate or extrapolate from the calibrating intercomparisons. We use the term 'metafitting' for the choices that are made before a fitting procedure is operationally adopted. We present methods for calculating the standard uncertainty for general, weighted least-squares fits and a method for optimizing these weights for a general noise model suitable for many PTTI applications. We present the results of the metafitting of procedures for the use of a regular schedule of (hypothetical) high-accuracy frequency calibration of a maser time scale. We have identified a cumulative series of improvements that give a significant reduction of the expected standard uncertainty, compared to the simplest procedure of resetting the maser synthesizer after each calibration. The metafitting improvements presented include the optimum choice of weights for the calibration runs, optimized over a period of a week or 10 days.
Document ID
19950025919
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Douglas, Rob J. (National Research Council of Canada Ottawa Ontario, Canada)
Boulanger, J.-S. (National Research Council of Canada Ottawa Ontario, Canada)
Date Acquired
September 6, 2013
Publication Date
May 1, 1995
Publication Information
Publication: NASA. Goddard Space Flight Center, The 26th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting
Subject Category
Physics (General)
Accession Number
95N32340
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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