VLBA SCIENTIFIC MEMO 23 IONOSPHERIC CORRECTIONS USING GPS BASED MODELS
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VLBA SCIENTIFIC MEMO 23
IONOSPHERIC CORRECTIONS USING GPS BASED MODELS
Craig Walker
National Radio Astronomy Observatory
Shami Chatterjee
Cornell University
Abstract:
Corrections for the effects of the ionosphere on VLBI phases have been tested using a geodetic project and a phase referencing test observation. Dual frequency S/X measurements on strong sources with very good positions are treated as ``truth'', and calibrations derived from GPS based ionospheric models are compared to them. All of the GPS models appear capable of reducing the effects of the ionosphere by a factor of roughly 2 to 5 and so provide a valuable aid for phase referencing observations. The SATLOC model does not appear to have advantages over the global models archived at CDDIS, despite a finer grid in space and time. Therefore it does not appear to be worth the effort to establish an in-house SATLOC archive.
- Background.
- The Observations.
- The Global Ionosphere Models
- Corrected Phases in TP015
- Direct Comparison of Delays in TP015
- RDV11 Results
- TP015 Phase Referenced Imaging Results
- Conclusions
- About this document ...
Craig Walker
2000-03-30
