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| Titel |
Geodetic VLBI Intensive scheduling based on singular value decomposition |
| VerfasserIn |
Judith Pietzner, Axel Nothnagel |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052963
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| Zusammenfassung |
| The scheduling of Very Long Baseline Interferometry (VLBI) observing sessions is a crucial
step to obtain reliable results with the best possible accuracy. At present, there is no clear
strategy for the scheduling of VLBI Intensive sessions for the purpose of dUT1
determination. Here, a new approach for scheduling one hour long Intensive VLBI sessions is
presented based on singular value decomposition (SVD).
The SVD is a tool that enables a detailed analysis of a matrix X by the decomposition
into three matrices that contain the singular values as well as the left-singular vectors (a basis
for data space of the matrix X) and the right-singular vectors (a basis for model
space of the matrix X). Assuming a least-squares adjustment of the observations
for a given schedule, the Jacobian matrix containing the partial derivatives of the
functional model with respect to the unknown parameters can be built. The parameters
that are usually estimated for an Intensive are: zenith wet delay at both stations,
one relative clock offset and one rate as well as the phase of the Earth’s rotation,
ΔUT1.
Here we present preliminary results of the scheduling strategy based on SVD. By
performing SVDs of the Jacobian matrix, the geometrical concept of projections onto the
model space and the data space is used to derive indicators of how precisely the
model parameters are determined from the observations and how well the adjusted
observations match the original ones. Thereby, a schedule is obtained that is – in sense of a
least-squares adjustment – optimal for the parameters that are presumably estimated. Thus,
this strategy might improve the determination of the phase of the Earth’s rotation. |
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