Atmospheric ties in the geodetic combinations: Implications for a global terrestrial reference frame
Abstract
A stable and accurate global terrestrial reference frame (TRF) is one of the key elements in high-precision geodetic applications. State-of-the-art TRFs (e.g., ITRF2014) are multi-technique combinations that include physically measured ties between geodetic stations at local sites. Despite the need for accurate local ties, errors remain significant. For example, discrepancies between space geodetic solutions and terrestrial local ties can reach the 5-mm level for about 50% of the tie vectors between VLBI, SLR, and GPS stations that are available at core geodetic sites. The error stems from the challenge of measuring station reference points that are inaccessible. The effect will likely worsen as new geodetic core sites are developed, unless new approaches are advanced. We propose a method whereby atmospheric structure is used to constrain atmospheric parameters between collocated (GPS) stations. The method assumes that improved local atmospheric treatment improves relative positioning given the high-degree of correlation in geodetic processing between atmospheric parameters and vertical site position parameters. We further combine a GPS-only TRF using the geodetic solutions with atmospheric constraints/ties, and evaluate its accuracy and stability. Our preliminary results show that the RMS residual of the vertical component for local baselines improves when imposing atmospheric constraints that incorporate Kolmogorov turbulence theory. Spectral analysis of baselines estimates suggests that daily independent atmospheric constraints reduce the amplitude of not only high-frequency variability but also low-frequency variability such as seasonal. We will present the method and results, and will discuss the possibility of improvements in TRF accuracy and stability when using atmospheric ties in geodetic solutions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.G23C0772M
- Keywords:
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- 1229 Reference systems;
- GEODESY AND GRAVITY;
- 1295 Integrations of techniques;
- GEODESY AND GRAVITY;
- 1299 General or miscellaneous;
- GEODESY AND GRAVITY