diff --git a/GPS_pw_modeling.mo b/GPS_pw_modeling.mo
index d859e12c0edfc751122ce08df39895a16595614c..cbbb6da8cdea8d55589cd3a7c40d1707e8512c19 100644
--- a/GPS_pw_modeling.mo
+++ b/GPS_pw_modeling.mo
@@ -242,7 +242,7 @@ package GPS_pw_modeling
connect(slow_and_fast.y, GPS_pw_simulator1.on_signal) annotation(
Line(points = {{2, 50}, {78, 50}, {78, 50}, {80, 50}}, color = {255, 0, 255}));
annotation(
- experiment(StartTime = 0, StopTime = 300, Tolerance = 1e-6, Interval = 0.0006),
+ experiment(StartTime = 0, StopTime = 2000, Tolerance = 1e-6, Interval = 0.0006),
__OpenModelica_simulationFlags(lv = "LOG_STATS", s = "dassl"));
end test_GPS;
diff --git a/paper/sections/06-results.tex b/paper/sections/06-results.tex
index 1c004525326adcabefd8a842d762b879e2b33eca..fe94fdafe416a8b7b5477a5cc3644f13e9d5956e 100644
--- a/paper/sections/06-results.tex
+++ b/paper/sections/06-results.tex
@@ -43,14 +43,13 @@ Some previous works cited in section~\ref{sec:related} discuss the TTFF but none
Up to the limited extent to which they are comparable -- due to the fact that are used Assisted-GPS sensors and the extra software layers included in the experiments -- the results are coherent with what discussed here. Our model on the other side achieves more generality not being dependent on the specific implementation on the given device. Moreover it allows to look directly at what are the theoretical performances we should expect from a GPS sensor without the overhead that is introduced by the operative system of a smartphone.
-Next we want to show how our model captures the expiration of the ephemeris data and the loss of visibility or the satellites. Figure~\ref{fig:control2} and~\ref{fig:position2} shows a duty cycling of the sensor for quickly acquiring position -- wartm start. At time $t = 1860 sec$ the ephemeris data expire making the duty cycling ineffective. Only after a prolonged period being turne
+---------------------------------------------------
--------------------------------------------
- and a prolonged turn\_ON signal is required in order to update the ephemeris data and make available again the position. In figure~\ref{fig:control2} we can see the described turn\_ON signal while in~\ref{fig:position2} we can see the availability of the position measure. In this example the ephemeris data expire around time=1880 , we can see how the sampling suddently becomes uneffective and the position becomes available again only after around a minute in which it is continuously turned on and reads the ephemeris data.
+Next we want to show how our model captures the expiration of the ephemeris data and the loss of visibility or the satellites. Figure~\ref{fig:control2} and~\ref{fig:position2} show a duty cycling of the sensor for quickly acquiring position -- i.e. a series of warm starts. At time $t = 1861 sec$ the ephemeris data expire making the duty cycling ineffective. Only after a prolonged period of time of the sensor being turned on, during which the device updates the ephemeris data, the position becomes available again as well as the possibility of performing warm starts.
\begin{figure}[h]
\begin{center}
- \includegraphics[width=0.70\columnwidth]{images/control2.png}
+ \includegraphics[height=0.30\columnwidth, width=0.80\columnwidth]{images/control2.png}
\caption{Control signal for the antenna in the simulation of the expiration of ephemeris data.
\label{fig:control2}
}
@@ -59,13 +58,36 @@ Next we want to show how our model captures the expiration of the ephemeris data
\begin{figure}[h]
\begin{center}
- \includegraphics[width=0.70\columnwidth]{images/position2.png}
+ \includegraphics[height=0.30\columnwidth, width=0.80\columnwidth]{images/position2.png}
\caption{Availability of the position measure in the simulation of the expiration of ephemeris data.
\label{fig:position2}
}
\end{center}
\end{figure}
--------------------------------------------
+
+Last simulation of this section will show how the model captures the loss of visibility of the satellites. This is done with the variable \texttt{visible\_satellites} which as defined in section~\ref{sec:gps} is an input of the system. The number of visible satellites (shown in figure`\ref{fig:control3}) is initially 5 for 100 seconds, allowing for the acquisition of the ephemeris data. At time $t = 100 sec$ two satellites disappear from the visible sky. Since three is not a sufficient number for the device to position itself the position stops being available, this is shon in figure~\ref{fig:position3}. Then at time $t = 200 sec$ one new satellite appears in the visible sky and after the device acquires its ephemeris data the position becomes visible again.
+
+\begin{figure}[h]
+ \begin{center}
+ \includegraphics[height=0.30\columnwidth, width=0.80\columnwidth]{images/control3.png}
+ \caption{Control signal and visible satellites for the antenna in the simulation of loss of stellite visibility.
+ \label{fig:control3}
+ }
+ \end{center}
+\end{figure}
+
+\begin{figure}[h]
+ \begin{center}
+ \includegraphics[height=0.30\columnwidth, width=0.80\columnwidth]{images/position3.png}
+ \caption{Availability of the position measure in the simulation of loss of satellite visibility.
+ \label{fig:position3}
+ }
+ \end{center}
+\end{figure}
+
+This last simulation points out also one limitation of the proposed model. In fact theoretically if the satellite that appears again after the loss of visibility was one of the two that previously disappeared the device would not need to re-acquire the ephemeris data, having still in memory the ones acquired at the start up and being those still valid. But to capture this we would have to capture separately the acquisition of the signal and ephemeris data of the different satellites, together with their visibiliy. This apparently would increase the complexity of the model and decrease it usability\footnote{An extension of the model to include also this phenomenon would't be very difficult. It would be sufficient to have parallel state machines similar to the one shown in figure~\ref{fig:cyberdynamics} that independently capture the tracking of the different satellites. Some more adjustments would of course be needede but the basic ideas would still hold.}.
+------------------------------------------------
+
\subsection{Power Consumption Accuracy Trade Off}
\label{sec:res:tradeoff}