Events Calendar
Single-band absolute astrometry: mitigation of the ionospheric contribution
Thursday September 8, 2022
2:00 pm
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Presenter: | Leonid Petrov (NASA) |
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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 | |