Thesis: Intro+Conclusion: WuotD

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Eric Teunis de Boone 2023-10-19 18:25:07 +02:00
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\chapter{Conclusion}
\label{sec:conclusion}
Using radio antennas to detect \glspl{UHECR} has received much attention recently.
The \acrlong{Auger} is currently being upgraded to \gls{AugerPrime} incorporating radio detectors with scintillators and water-cherenkov detectors.
Other experiments, such as \gls{GRAND}, plan\Todo{word} to fully rely on radio detection only.
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% Timing not enough
Time information in such large observatories is typically distributed using \glspl{GNSS}, reaching up to $10\ns$ accuracy under very good conditions.
For analysis using radio interferometry to be competitive, this timing accuracy needs to be improved towards the $1\ns$ (see Figure~\ref{fig:}).
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% Beacon introduction
A viable method to obtain this timing accuracy is to incorporate a beacon transmitter into the array.
This (narrow-band) transmitter sends out a special\Todo{word} signal that is picked up by the radio antennas in the array.
With relatively simple techniques, the timing accuracy can be improved to below $1\ns$ (see Figures~\ref{fig:},~\ref{fig:}).
Thus, at a relatively low cost, the (relative) timing of radio arrays can be improved to enable radio interferometry.
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%
In some circumstances, an external transmitter can be used as a beacon.
For example, in \gls{Auger}, a public TV broadcaster emits its signal at $f = 62.75\MHz$ from \Todo{name} (approximately $75\;\mathrm{km}$ north-west of the array\Todo{verify}).
With the source location and the frequency known, time delays can be calculated and this signal can be used to remove\Todo{word} timing errors smaller than $T = 1/f \sim 16\ns$.
Unfortunately, with the \gls{GNSS} timing accuracy estimated in the same order of magnitude and the signal being periodic, the synchronisation of the antennas can be off by an integer amount of periods $T$.\Todo{rewrite}
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Recording an air shower, in addition to such a narrow-band beacon, might provide a method to determine the correct beacon period.
Radio interferometeric analysis of the air shower depends on the coherence of the received signals.
Any synchronicity problems in the radio antennas decrease the observed power of the reconstructed air shower.
With a limited set of periods to try\Todo{word}, this power can be maximised \Todo{word} while simultaneously determining the correct beacon period.
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\end{document}

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@ -187,7 +187,7 @@ In recent and upcoming experiments, such as \gls{Auger}, \gls{GRAND} or \gls{LOF
With distances up to $1.5\;\mathrm{km}$ (\gls{Auger}), the detectors therefore have to operate in a self-sufficient manner\Todo{word} with only wireless communication channels.
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Standalone detectors typically receive their timing from a \gls{GNSS}.
These standalone detectors typically receive their timing from a \gls{GNSS}.
Previously, for timing of water-Cherenkov detectors, this timing accuracy was better than the resolved data\Todo{rephrase}.
Even for the first analyses of radio data, this was sufficient.
However, for advanced analyses such as radio interferometry, the timing accuracy must be improved.
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% Structure summary
In this thesis, a solution to enhance the timing accuracy of air shower radio detectors is worked out\Todo{word}.
First, introductions to radio interferometry and waveform analysis are given in Chapters~\ref{sec:interferometry}~and~\ref{sec:waveform}.
First, an introduction to radio interferometry is given in Chapter~\ref{sec:interferometry}.
This will be used later on and gives an insight into the timing accuracy requirements.
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Chapter~\ref{sec:waveform} reviews typical techniques to analyse waveforms to obtain timing information.
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Chapter~\ref{sec:disciplining} introduces the concept of a beacon transmitter to synchronise an array of radio antennas using techniques from the preceding chapter to constrain the achievable timing accuracy.
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Chapter~\ref{sec:single_sine_sync} shows\Todo{word} how a sine wave beacon can synchronise an array while using the radio interferometric approach to resolve\Todo{word} an airshower.
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Finally, Chapter~\ref{sec:gnss_accuracy} investigates the limitations of the current hardware in \gls{GRAND} and its ability to record and reconstruct a beacon signal.