NASA GSFC global geodetic VLBI solution gsf_2024d
DOI: 10.25966/yksm-gw15
NASA Goddard Space Flight Center global VLBI quarterly solution
gsf_2024d provides estimates of stations positions, station velocities,
harmonic variations in site positions, parameters of non-linear station
motions, positinos of extragalactic radio sources, and the estimates
of an expansion of the Earth orientation parameters into harmonic
and B-spline bases from processing
all publicly accessible Very Long Baseline Interferometry
(VLBI) group delays derived from processing all available geodetic
VLBI observations since
1980.04.11
through
2024.12.03
,
in total,
19,535,536
group delays
from
19,963
experiments.
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.
Geophysics Results
Station positions and velocities
Positions of 190
stations,
their velocities, and parameters of non-liner motion were estimated as global
parameters. The dependence of station position on time is expressed as
X(t) = X0 + X'(t - t0) +
∑
j
(
hcj cos ωj t +
hsj sin ωj t
)
+
∑ n-1
k bk
Bmk (t k),
where X0 is the station positions at the reference epoch 2000.01.01,
X' is its linear velocity, hsj and hcj
are sine and cosine components of harmonic variations with frequency ωj,
and bk are the coefficients of expansion of station position over the
B-spline basis of the m-th degree at sequence of knots [1-m, 1-m+1, 1-m+2 ...].
The knots of the B-spline can me multiple. Non-linear motion is estimated only
for some stations.
Boundary conditions were selected in such a way that source positions,
station positions and velocities are compatible with IERS C04 series of the
Earth orientation parameters
IERS C04 time series,
i.e. have no bias and not trend over a specified period of time.
Antenna axis offsets
Antenna axis offsets from LSQ estimation
gsf_2024d.axof
Earth orientation parameters
Pole coordinates X, Y, UT1 angle, and their rate, daily correction to the
nutation in longitude and nutation in obliquity were estimated for each
session separately.
Adjustments to path delays in the neutral atmosphere
Statistics
Statistics of observing campaigns
Miscellaneous
Acknowledgments
We acknowledge staff at VLBI observing stations, VLBI correlators, and VLBI
data centers listed
here for their support of VLBI operations.
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Last update: 2025.04.03_02:07:26
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