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projects:mkat_sband:pub:fringefit [2020/11/10 14:13] wucknitz |
projects:mkat_sband:pub:fringefit [2020/11/10 14:56] (current) wucknitz |
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| We can test the gradient-hypothesis by fitting such a gradient (independent for each time) to the data and check how well it can reproduce the observed signal. We can do this per station or per baseline. The former has the advantage that we have to check less plots. | We can test the gradient-hypothesis by fitting such a gradient (independent for each time) to the data and check how well it can reproduce the observed signal. We can do this per station or per baseline. The former has the advantage that we have to check less plots. | ||
| + | Here are results for the antenna-based dispersive delay:\\ | ||
| + | {{:projects:mkat_sband:pub:1603186576_linxy_ant_disp.png?direct&600|gradient fit for antenna-based dispersive delay}} | ||
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| + | We see that the gradient fit (green) fits the observations (red) almost exactly for all stations. For the innermost stations (left) the noise dominates the signal, but the systematic variations still agree very well. This means the ionosphere really acts mostly as a large-scale time-varying gradient. | ||
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| + | Here is the result for the non-dispersive delay:\\ | ||
| + | {{:projects:mkat_sband:pub:1603186576_linxy_ant_nondisp.png?direct&600|gradient fit for antenna-based non-dispersive delay}} | ||
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| + | For the outer stations (right) the agreement is still pretty good, but this is because we have only a few outer stations, which thus have a strong lever arm and dominate the solution. In contrast to the dispersive delay, this solutions does not fit the inner stations (left) well. Fluctuations there are dominated by small-scale and more local variations. | ||
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| + | Here are PDF files of all these solutions for completeness: | ||
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| + | {{:projects:mkat_sband:pub:1603186576_linxy_ant_disp.pdf|gradient fit for antenna-based dispersive delay}}\\ | ||
| + | {{:projects:mkat_sband:pub:1603186576_linxy_ant_nondisp.pdf|gradient fit for antenna-based non-dispersive delay}}\\ | ||
| + | {{:projects:mkat_sband:pub:1603186576_linxy_bl_disp.pdf|gradient fit for baseline-based dispersive delay}}\\ | ||
| + | {{:projects:mkat_sband:pub:1603186576_linxy_bl_nondisp.pdf|gradient fit for baseline-based non-dispersive delay}} | ||
