 |
| Titel |
On the joint inversion of SGG and SST data from the GOCE mission |
| VerfasserIn |
P. Ditmar, P. Visser, R. Klees |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7340
|
| Digitales Dokument |
URL |
| Erschienen |
In: G1. The new gravity field mission (CHAMP, GRACE, GOCE): from measurements to geophysical interpretation ; Nr. 1 (2003-06-30), S.87-94 |
| Datensatznummer |
250000040
|
| Publikation (Nr.) |
 copernicus.org/adgeo-1-87-2003.pdf |
|
|
|
|
|
| Zusammenfassung |
The computation of spherical harmonic coefficients
of the Earth’s gravity field from satellite-to-satellite
tracking (SST) data and satellite gravity gradiometry (SGG)
data is considered. As long as the functional model related to
SST data contains nuisance parameters (e.g. unknown initial
state vectors), assembling of the corresponding normal matrix
must be supplied with the back-substitution operation,
so that the nuisance parameters are excluded from consideration.
The traditional back-substitution algorithm, however,
may result in large round-off errors. Hence an alternative approach,
back-substitution at the level of the design matrix,
is implemented. Both a stand-alone inversion of either type
of data and a joint inversion of both types are considered.
The conclusion drawn is that the joint inversion results in a
much better model of the Earth’s gravity field than a standalone
inversion. Furthermore, two numerical techniques for
solving the joint system of normal equations are compared:
(i) the Cholesky method based on an explicit computation
of the normal matrix, and (ii) the pre-conditioned conjugate
gradient method (PCCG), for which an explicit computation
of the entire normal matrix is not needed. The comparison
shows that the PCCG method is much faster than the
Cholesky method.
Key words. Earth’s gravity field, GOCE, satellite-tosatellite
tracking, satellite gravity gradiometry, backsubstitution |
| |
|
| Teil von |
|
|
|
|
|
|
|
|