Thesis: Intro+Conclusion: WuotD

documents/thesis/chapters/conclusion.tex

@@ -10,5 +10,34 @@
 \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.
+\\
+% 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:}).
+\\
+
+% 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.
+\\
+
+% 
+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}
+\\
+
+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.
+\\
+
 
 \end{document}

documents/thesis/chapters/introduction.tex

@@ -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.
 \\
 
-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.
@@ -195,7 +195,18 @@ However, for advanced analyses such as radio interferometry, the timing accuracy
 
 % 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.
+\\
+Chapter~\ref{sec:waveform} reviews typical techniques to analyse waveforms to obtain timing information.
+\\
+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.
+\\
+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.
+\\
+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.
+
+