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| Titel |
Extending the GPS satellite antenna patterns of the IGS to nadir angles beyond 14â using LEO data |
| VerfasserIn |
Rolf Dach, Adrian Jäggi, Heike Bock, Gerhard Beutler, Oliver Montenbruck, Ralf Schmid, Yago Andres |
| 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 |
250048362
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| Zusammenfassung |
| The absolute phase center model adopted by the International GNSS Service (IGS) in 2006 is
based on robot calibrations for a number of terrestrial GNSS receiver antennas and consistent
correction values for the GNSS transmitter antennas estimated from data of the global IGS
tracking network. As the calibration of the satellite antennas is solely based on terrestrial
measurements, the estimation of their phase patterns is limited to a nadir angle of
14-. This is not sufficient for the analysis of spaceborne GPS data collected by low
Earth orbiting (LEO) satellites that record observations at nadir angles of up to 17-.
Moreover, phase center variation (PCV) estimates for nadir angles close to 14-
derived from terrestrial measurements might be affected by uncertainties in the
troposphere modeling. This drawback may also be overcome by the use of LEO
data.
We use GPS tracking data from the LEO missions Jason–2, MetOp–A, GRACE, and
GOCE to extend the IGS satellite antenna patterns to nadir angles beyond 14-. In order to
achieve estimates that are consistent with the PCVs currently used within the IGS, GPS and
LEO orbits are fixed to solutions obtained by adopting the IGS conventional values. Due to
significant near-field multipath effects in the LEO spacecraft environment, it is necessary to
solve for GPS (nadir–dependent only) and LEO (azimuth– and elevation–dependent) antenna
patterns simultaneously. We analyze the separability of these parameters and discuss
appropriate constraints. We assess the contribution of the different LEO missions to a
combined solution and analyze the impact of the extended PCVs on LEO precise orbit
determination results. |
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