diff --git a/src/Glossary.tex b/src/Glossary.tex
index 82cb2ba..d723bdb 100644
--- a/src/Glossary.tex
+++ b/src/Glossary.tex
@@ -78,6 +78,12 @@
 		}]
 {Alt-Az}{Alt/Az mount}{Altazimuth mount}
 
+\newacronym[
+	description={two-line element set is a data format encoding a list of orbital elements of an Earth-orbiting object for a given point in time, the epoch. Using a suitable prediction formula, the state (position and velocity) at any point in the past or future can be estimated to some accuracy. TLEs can describe the trajectories only of Earth-orbiting objects. TLEs are widely used as input for projecting the future orbital tracks of space debris for purposes of characterizing ``future debris events to support risk analysis, close approach analysis, collision avoidance maneuvering'' and forensic analysis. The format was originally intended for punched cards, encoding a set of elements on two standard 80-column cards%
+			\footnote{\scriptsize{\url{https://en.wikipedia.org/w/index.php?title=Two-line_element_set&oldid=1104028347}}}
+		}]
+{TLE}{TLE}{two-line element set}
+
 %%%%%%%%%%%%
 % GLOSSARY %
 %%%%%%%%%%%%
diff --git a/src/Ground_Stations.tex b/src/Ground_Stations.tex
index 053c038..d834c15 100644
--- a/src/Ground_Stations.tex
+++ b/src/Ground_Stations.tex
@@ -17,12 +17,12 @@
 \subsection{SatNOGS Ground Stations}
 \index{ground stations}\index{Libre Space Foundation}
 The \gls{LSF} built the \gls{SatNOGS} network using distributed,
-volunteer-run, \gls{RF} \glspl{ground-station}, such as in
+volunteer-run, \gls{RF} \glspl{ground-station} using \glspl{SDR}, such as in
 figure \ref{fig:spacecruft-rotator}, page \pageref{fig:spacecruft-rotator}.%
 \footnote{\scriptsize{\url{https://spacecruft.org/assets/i/spacecruft-rotator.png}}}
 It shows a \gls{SatNOGS} \gls{ground-station} with \gls{VHF} (right) and \gls{UHF} (left)
-\glspl{antenna} on a \gls{mast} with \gls{Alt-Az} \gls{rotator}.
-\index{radio}\index{RF}\index{VHF}\index{UHF}\index{rotator}\index{antenna}
+\glspl{antenna} on a \gls{mast} with an \gls{Alt-Az} \gls{rotator}.
+\index{radio}\index{SDR}\index{RF}\index{VHF}\index{UHF}\index{rotator}\index{antenna}
 
 \begin{figure}[h!]
 	\begin{center}
diff --git a/src/Hardware.tex b/src/Hardware.tex
index a83af73..224383b 100644
--- a/src/Hardware.tex
+++ b/src/Hardware.tex
@@ -199,7 +199,7 @@ is:
 \begin{itemize}
 	\item The Imaging Source DMX camera with Sony IMX174 CMOS. \index{The Imaging Source}\index{IMX174}
 	\item Kowa 50mm f1.4 C-mount lens.\index{Kowa}
-	\item Odroid N2 running \gls{Debian}. \index{Odroid}\index{Debian}
+	\item Odroid N2 running \gls{Debian} \gls{GNU} \gls{Linux} system. \index{Odroid}\index{Debian}\index{GNU}\index{Linux}
 	\item Odroid N2 plastic enclosure, large half, hole drilled for ad-hoc mounting.
 	\item Blower fan on top, with power cable (came with Bosch enclosure). \index{fan}
 	\item Fan, maybe not so useful, with power cable (came with Bosch enclosure).
diff --git a/src/Operation.tex b/src/Operation.tex
index b3fa4c6..1f49e38 100644
--- a/src/Operation.tex
+++ b/src/Operation.tex
@@ -25,7 +25,7 @@ cd stvid/
 source env/bin/activate
 \end{minted}
 
-Get the latest TLEs:
+Get the latest \glspl{TLE}:
 \index{TLE}
 
 \begin{minted}{sh}