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Center for Astrophysics Research and Technologies Seminar Series Information


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Single-band absolute astrometry: mitigation of the ionospheric contribution

Thursday September 8, 2022
2:00 pm

 Presenter:  Leonid Petrov (NASA)
 Series:  Center for Astrophysics Research and Technologies Seminar Series
 Abstract:  Radio measurements can provide absolute astrometry with high precision allowing for parallax distances within our Milky Way Galaxy and the establishment of a celestial reference frame.  The ionospheric contribution affects path delay. When simultaneous dual-band observations are used for absolute astrometry, the residual unaccounted contribution of the ionosphere is at a level of several picoseconds. But there are two cases when we need to process single band group delays: a) some observations provided usable data only for one band; b) an entire experiment used only one band. A common approach is to utilize Global Navigation Satellite System (GNSS) Total Electron Content (TEC) maps for computing the contribution of the ionosphere to group and phase delays. I made an attempt to account rigorously for remaining ionosphere-related errors and their impact on source position estimates. This is achieved by developing an empirical stochastic model, applying fudge factors, and applying a de-bias model. The goal is to get the best solutions for these two cases and provide realistic estimates of residual errors. 
 Host:  Gregory Taylor
 Location:  PAIS-3205, PAIS

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