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Estimation of EOP from VLBI: Direct Approach

Published online by Cambridge University Press:  12 April 2016

L. Petrov
L. Petrov*
Affiliation:
Code 926, NVI, Inc./NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

Abstract

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The currently adopted strategy of EOP estimation from VLBI is to estimate six parameters: UT1, UT1 rate, pole positions and nutation offsets for each 24-hour session independently. Then the resulting time series of raw Earth orientation parameters are filtered and a regression analysis is performed in order to obtain nutation coefficients, polhode of the pole and other physical parameters. Thus, the latter parameters are obtained indirectly in two stages. An alternative approach of direct estimation of the final Earth orientation parameters is presented. Pole coordinates and UT1 are considered as a sum of three components: the low-period component which is modeled by a cubic spline, the harmonic component which includes forced nutation, precession and sub-daily variations of EOP, and the stochastic component which is modeled by a linear spline with segment length 1-2 hours. All parameters are obtained in a single LSQ solution using all available data.

Type
Section 2. Improved Definitions and Models
Information
International Astronomical Union Colloquium , Volume 180: Towards Models and Constants for Sub-Microarcsecond Astrometry , March 2000 , pp. 254 - 258
Copyright
Copyright © US Naval Observatory 2000

References

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