NASA Goddard Space Flight Center   Geodesy and Geophysics Laboratory

NASA GSFC global geodetic VLBI quarterly solution

NASA Goddard Space Flight Center global geodetic Very Long Baseline Interferometry (VLBI) quarterly solutions provide estimates of stations positions, station velocities, harmonic variations in site positions, parameters of non-linear station motions, positions of extragalactic radio sources, and the estimates of an expansion of the Earth orientation parameters into harmonic and B-spline bases. These parameters were adjusted in a single least square analysis by analyzing group delays derived from processing all publicly available geodetic VLBI experiments accumulated since the1980s till present.

The latest quarterly global VLBI geodetic solution: gsf_2024d

Methods of data analysis are described in full detail in Petrov & Kovalev, "The Radio Fundamental Catalog", 2025, The Astrophysical Journal Supplement Series, 276:38 (51pp), doi: 10.3847/1538-4365/ad8c36.