The Celestial Frame and the Weighting of the Celestial Pole Offsets in the Computation of VLBI-Based Corrections for the Main Lunisolar Nutation Terms.

Víctor Puente,Marta Folgueira

doi:10.3390/s21248276

Abstract

Very long baseline interferometry (VLBI) is the only technique in space geodesy that can determine directly the celestial pole offsets (CPO). In this paper, we make use of the CPO derived from global VLBI solutions to estimate empirical corrections to the main lunisolar nutation terms included in the IAU 2006/2000A precession–nutation model. In particular, we pay attention to two factors that affect the estimation of such corrections: the celestial reference frame used in the production of the global VLBI solutions and the stochastic model employed in the least-squares adjustment of the corrections. In both cases, we have found that the choice of these aspects has an effect of a few μas in the estimated corrections.

Highlights

Corrections for the Main LunisolarThe study of the nutation of the Earth is fundamental in two aspects: to infer the structure of the Earth’s interior and to determine the orientation of the Earth’s axis in the inertial frame
In this paper we studied the influence of the celestial reference frame and the stochastic model of the least-squares fitting in the estimation of empirical corrections to the main lunisolar nutation terms of the IAU 2006/2000A precession–nutation model
We used celestial pole offsets (CPO) derived from global Very long baseline interferometry (VLBI) solutions

Summary

Introduction

Corrections for the Main LunisolarThe study of the nutation of the Earth is fundamental in two aspects: to infer the structure of the Earth’s interior and to determine the orientation of the Earth’s axis in the inertial frame. Very long baseline interferometry (VLBI) is the technique that allows the most regular and precise observations of the nutation of the Earth by means of the observations of extragalactic radio sources, according to [1], lunar laser ranging (LLR) has the potential to determine celestial pole offsets (CPOs) with an accuracy comparable to VLBI. Several analysis centers (ACs) contribute to the International VLBI Service for Geodesy and Astrometry (IVS, [2]), providing EOP time series estimated from the analysis of VLBI observations. The IVS series of CPOs are later processed and compiled in the IERS long-term series [4] with the rest of the EOPs that are produced by means of other space geodesy techniques under the umbrella of the corresponding services

Methods

Results

Conclusion