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authorRefik Hadzialic2012-09-07 15:26:29 +0200
committerRefik Hadzialic2012-09-07 15:26:29 +0200
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Results changes
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-rw-r--r--vorlagen/thesis/src/kapitel_x.tex248
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diff --git a/vorlagen/thesis/maindoc.pdf b/vorlagen/thesis/maindoc.pdf
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--- a/vorlagen/thesis/maindoc.pdf
+++ b/vorlagen/thesis/maindoc.pdf
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diff --git a/vorlagen/thesis/src/bib/literatur.bib b/vorlagen/thesis/src/bib/literatur.bib
index ca24e12..4edb3d5 100644
--- a/vorlagen/thesis/src/bib/literatur.bib
+++ b/vorlagen/thesis/src/bib/literatur.bib
@@ -784,6 +784,14 @@ ISSN={0018-9251},}
year = "2012"
}
+@misc{academicPhrase,
+ author = "John Morley",
+ howpublished = "\url{http://www.edri.org/edrigram/number10.2/silent-sms-tracking-suspects}",
+ note = "[Online; accessed 1-September-2012]",
+ title = "Academic Phrasebank",
+ year = "2005"
+}
+
@misc{silentPolice,
author = "European Digital Civil Rights",
howpublished = "\url{http://www.edri.org/edrigram/number10.2/silent-sms-tracking-suspects}",
diff --git a/vorlagen/thesis/src/kapitel_x.tex b/vorlagen/thesis/src/kapitel_x.tex
index 341a9f9..638f480 100644
--- a/vorlagen/thesis/src/kapitel_x.tex
+++ b/vorlagen/thesis/src/kapitel_x.tex
@@ -2250,7 +2250,7 @@ system has been successfully configured and set in operation it was followed by
to verify if it was operating correctly. Initially, the system was
tested with 2G cell phones (Nokia 3310 and Siemens M50) and its correctness was verified.
While the system was tested with smart phones, a strange behaviour could be noticed.
-Sometimes the smart phones ($iPhones$ $3GS$ and $4$) could not detect existance of the
+Occasionally the smart phones ($iPhones$ $3GS$ and $4$) could not detect existance of the
GSM network at all, i.e. the network could not be found in the search menu where
all GSM networks in range are shown. The reason for this strange phenomenon may be found
in the unstable operation of the cheap clock oscillator. Although the clock unstability
@@ -2276,7 +2276,7 @@ The RRLP request was immediatelly sent after the paging request has been obtaine
This evidence justifies the time out behaviour. Once the option for sending RRLP requests
while the paging is in progress was disabled, this problem was solved!
Next step was to manually send the RRLP requests from the OpenBTS terminal
-to smart phones. Contrary to expectations, the smart phones sometimes received the
+to smart phones. Contrary to expectations, the smart phones occasionally received the
RRLP request as an SMS message and did not provide any response.
In the case where the smart phones did not receive the
RRLP request as an SMS message, still no response was produced.
@@ -2491,19 +2491,20 @@ int response = gsm48_send_rr_app_info(conn, 0x00, AlmanacPackets[packNum].length
\chapter{Results}
-One of the most important parts of this thesis are the results that
-shall be presented in this chapter. Tests will be explained and how the results
-were obtained. Analysis of the results by the time required to perform a
-localization of a GSM user and the geographical dislocation error using
-Google maps are going to be discussed. Smart phones used
-for the test are going to be introduced and followed by the location
-of the tests. After the results have been provided,
-a section with criticism demonstrates all the obstacles that may have appeared
-while the tests have been performed and why some of the results may be biased. The criticism
-section is a vital part of this thesis, aside from the given theoretical and
-mathematical perspective of how AGPS works and why lack of time synchronization inside
-GSM can be of critical value to correctly evaluate the results. It gives an additional
-insight into the complete operation of the built localization system in this thesis.
+One of the most important parts of this thesis are the results.
+Performed tests will be explained and how the results
+were obtained. Analysis of the results will be discussed as well as the geographical
+dislocation error will be shown. Smart phones used
+for the test are going to be introduced, followed by showing the location
+where the tests have been performed. After the results have been provided,
+a critical analysis demonstrates all the obstacles that may have emerged
+while the tests have been performed. The critical analysis may provide
+the answer why some results may be biased and it is a vital part of this thesis.
+It gives an additional insight into the complete operation of the built localization
+system in this thesis.
+%Aside from the given theoretical perspective of how AGPS works and why lack of
+%time synchronization inside GSM can be of critical value to correctly
+%evaluate the results.
\section{Tests \& Results}
\label{sec:tstRes}
@@ -2513,12 +2514,12 @@ computer pool of the University of Freiburg (German: $Mathematik$ $Rechenzentrum
and outside of the computer pool.
\subsection{Smart phones tested}
-The requirement for a cell phone to be taken into account for testing was its
+The requirement for a cell phone to be considered for testing was its
classification as a smart phone (having at least an AGPS receiver) and
its availability (person's good will to share their smart phone for the
-purpose of testing). The following eleven models have satisfied the
-criterion and have been used to perform the tests, as given in
-table \ref{tbl:smartphones}.
+purpose of testing). The following eleven models, shown in
+table \ref{tbl:smartphones} have satisfied the
+criterion and have been used to perform the tests.
\begin {table}[ht]
\caption{Smart phone models used for testing in the thesis.}
@@ -2543,14 +2544,13 @@ $Galaxy$ $S3$&Samsung, South Korea
As stated in section \ref{sec:tstRes}, tests have been performed outside and inside
of the computer pool building. Three different test modes were tried out,
first only an RRLP request without any
-assistance data was sent. The second test included an RRLP request with almanac, UTC model, ionospheric model and
-reference location data. The last test was an RRLP request with almanac, ephemeris, UTC model,
+assistance data was sent. The second test included an RRLP request with almanac data only.
+The last test was an RRLP request with almanac, ephemeris, UTC model,
ionospheric model and reference location data. The stated requests have been sent in an
-reverse order, to observe if the smart phones can actually make an usage of the assistance data.
-The RRLP requests were manually sent from the telnet interface from OpenBSC after they have been
+reverse order, to observe if the smart phones can actually exploit and benefit from the assistance data.
+The RRLP requests were manually sent from the Telnet interface from OpenBSC after they have been
implemented by the author. Results delivered by the MS were stored in the database and the
-following analysis is based on them and on the time out results which were not stored in the
-database but notices by the author.
+following analysis is based on the results.
\begin{figure}[ht!]
\centering
@@ -2562,23 +2562,21 @@ database but notices by the author.
The first tests took place on the ground-floor of the computer pool,
in figure \ref{img:googlemapsResults} depicted with a green dot as Test room 1.
The smart phones were horizontally lying on the table $50 cm$ away from the window in the first test
-and in the second test vertically parallel to the window. The results of this two smart phone
-position tests in the room showed that smart phone position did not
-make any influence on the test results. The delivered position coordinates by the smart
-phones in all performed tests were in range of the green rectangle labeled with a white one.
+and in the second test vertically parallel to the window. The results of two smart phones, $iPhone$ $3GS$ and $G1$,
+showed that their position did not make any influence on the test results. The delivered position coordinates
+in two performed tests were in range of the green rectangle labeled with a white one in the left corner.
According to Google Earth, Test room 1 has the following coordinates: latitude 48\textdegree 0'13.21"N and
longitude 7\textdegree 50'53.53"E. The results were 5-20 m away from the
-real position according to Google Earth. The smart phones that provided these results
-were the $iPhone$ $3GS$ and $G1$. The $iPhone$ $3GS$ sent only a response when all assistance data
-(almanac, ephemeris, UTC model, ionospheric model and reference location data) have been delivered
-whereas the $G1$ only when the assistance data without ephemeris data were delivered or by only sending
-an RRLP request without any assistance data. It is apparent from these facts that the $iPhone$ $3GS$
-had used the assistance data to estimate its position otherwise it would send it is position back also
-when only an RRLP position request was sent. Interestingly, the $G1$ did not deliver any results
-when the ephemeris data have been delivered to it. These findings suggest that the AGPS receiver in
-$G1$ may not know how to employ the ephemeris data because it is one of the first ``real'' smart phones on the
-market. Later on it can be seen other smart phones that are even older than the $G1$ can not employ any of the
-assistance data.
+real position according to Google Earth. The $iPhone$ $3GS$ sent only a response when assistance data
+have been delivered (almanac or almanac with ephemeris, UTC model, ionospheric model and reference location data),
+whereas the $G1$ only when the almanac data were provided as well as a simple RRLP request without assistance
+data. It is apparent from these facts that the $iPhone$ $3GS$
+had used the assistance data to estimate its position. Otherwise the $iPhone$ $3GS$ would send its position back
+when only an RRLP position request was sent. Interestingly, the $G1$ did not provide any results
+when the ephemeris data have been delivered. These findings suggest that the AGPS receiver in
+$G1$ may suffer from not knowing how to employ the ephemeris data. This might be due to the fact that $G1$ is
+one of the first ``real'' smart phones on the market. Afterwards, evedince for smart phones not being able to utilise
+any of the assistance data, will be provided for other smart phones older than the $G1$.
\begin{figure}
~ %add desired spacing between images, e. g. ~, \quad, \qquad etc.
@@ -2604,62 +2602,65 @@ assistance data.
The second tests took place in Test room 2. Test room 2 is located in the basement of the
computer pool, with the following coordinates: latitude 48\textdegree 0'13.12"N and
-longitude 7\textdegree 50'53.50"E. The fact tests took place in the basement adds
-an additional obstacle to the AGPS receiver in the MS, the signal strength of GPS
-signals is even weaker. The GPS signal strength was measured with an external GPS receiver
+longitude 7\textdegree 50'53.50"E. The fact that the tests took place in the basement adds
+an additional obstacle to the AGPS receiver in the MS, the signal strengths of GPS
+signals are even weaker. The GPS signal strength was measured with an external GPS receiver
connected to the computer and by its acquisition time it could be easily observed that the
-time required to track the satellites was a few times longer than in the Test room 1.
+time required to track the satellites was much longer than in Test room 1.
The results from Test room 2 are most valuable because they have
provided additional evidence that even without line of sight it is possible to
-receive weak GPS signals and approximate the position. The obtained results from
-the tests in Test room 2 can be seen in figure \ref{img:googlemapsResults}, two
-red rectangles labeled with a two in the left upper corner.
-It is somewhat surprising that different cell phone models delivered different
+receive weak GPS signals and approximate the position. The line of sight was blocked by
+the surrounding buildings. The obtained results from
+Test room 2 can be seen in figure \ref{img:googlemapsResults}, two
+red rectangles labeled with a two in their left upper corner.
+It is somewhat surprising that different phone models delivered different
positions (two different rectangle ranges) at different times of the day.
-This finding suggests that not the equal number of satellites were visible
-at the different time points when the tests have been performed.
+This finding suggests that not an equal number of satellites may have been visible
+at the different time points when the tests were performed.
By observing the results in figure \ref{img:googlemapsResults},
-it is straightforward to see deviation of the estimated positions
+it is straightforward to see the deviations of the estimated positions,
by comparing the tests performed in Test room 1 and 2.
Albeit these two test rooms are geographically not far away from each other,
the major difference is in their altitude and GPS signal strength reception.
-The estimated position deviation from the real position was greater
-with the GPS signal reception quality and with reduced satellites visibility.
+The estimated position deviation from the real position was dependent on
+GPS signal reception quality and satellites visibility.
The majority of the performed tests in this work were performed in this room.
-Smart phones have been tested on the table which is $3 m$ away from the windows
+Smart phones have been tested on the table which is $2 m$ away from the windows
and on the window itself, as shown in figure \ref{img:smartphonepositions}.
These small changes in position of the smart phone did not make any difference
-in the resulting estimated position. The smart phones tested in Test
-room 2 were all the listed ones in table \ref{tbl:smartphones}. One
+in the estimated position. The smart phones tested in Test
+room 2 are listed in table \ref{tbl:smartphones}. One
unanticipated finding was that the ``newer generation'' smart phones did not
deliver their position in any case but rather requested more assistance data
like $iPhone$ $4$, $Galaxy$ $S2$ and $Galaxy$ $S3$. There are two possible
-explanations for this result.
+explanations for this behaviour.
This might be because the newer AGPS devices require more assistance data
by relying on the network providers to have synchronized GSM systems or it is an
security protection of the smart phone user. No information on the AGPS receiver
-chipset in the smart phones could be found online and author's given statements
-have to be considered with ambiguity. Another contrary to expectations, were the
-results with two Nokia ``smart phone'' models $E71$ and $N95$, results were only
-delivered when an RRLP request was sent without any assistance data. Although it was
-stated in their specifications both are equiped with an AGPS receiver
-RRLP requests with assistance data did not produce any output from these smart phones
-\citep{nokiae71} \citep{nokian95}. The reason for this is not clear but it might
-be due to the fact these are older models in comparison to other smart phones in
-the tests. At the time point when they were released by Nokia the firmware for the phones
-might not have been fully evolved and developed since both models are from the
+chipset in the smart phones could be found online by the author. The previous two
+statements have to be considered with ambiguity. Another contrary to expectations,
+were the results with two Nokia ``smart phone'' models $E71$ and $N95$. The
+results were only delivered when an RRLP request was sent without any assistance
+data. Although it was stated in their specifications that both cell phones are
+equiped with an AGPS receiver \citep{nokiae71} \citep{nokian95}.
+However, RRLP requests with assistance data did
+not produce any output from these smart phones. The reason for this behaviour is
+not completely obvious but it might be due to the fact these are older models
+in comparison to other smart phones in the tests.
+At the time point when the two cell phones were released by Nokia the firmware for the phones
+might not have been fully developed since both models are from the
same company.
The third test took place in Test room 3, as shown in figure \ref{img:googlemapsResults}
by the yellow dot. The third test room has the following coordinates:
-latitude 48\textdegree 0'12.26"N and longitude 7\textdegree 50'54.45"E.
+latitude 48\textdegree 0'12.26"N and longitude 7\textdegree 50'54.45"E.
The smart phones were placed on the windows.
-In this room the smart phones tested did not deliver any positions but only errors about
-missing assistance data and time outs. While no MS delivered its position, the room was
-tested if a GPS position can be obtained with an external GPS receiver.
+In this room, the tested smart phones did not deliver any positions but only errors about
+missing assistance data and time outs. While non of the smart phones delivered their position,
+the room was tested if a GPS position can be obtained with an external GPS receiver.
The test was successful and after 12 minutes the position was obtained but the signal
strength was weak according to the delivered GPS output. An implication emerging from
-this finding may be related to the GPS receiver high sensitivity (-160 dBm $10^{−16}$ mW)
+this finding may be related to the GPS receiver high sensitivity (-160 dBm = $10^{−19}$ W)
and an active patch antenna with a size of 2x2 cm \citep{ubxDatasheet}.
The GPS receivers employed in smart phones have to be small in size to fit into the device
and use a passive antenna because active antennas have an additional power consumption
@@ -2667,22 +2668,22 @@ and use a passive antenna because active antennas have an additional power consu
To determine if the delivered results are taken from the cache or some other memory in the
smart phone, the same test have been performed in the basement hallway where no
-windows exist just after the smart phones delivered successfully their position
+windows exist right after the smart phones have successfully delivered their position
in Test room 2. This test did not deliver any position but only time outs
or errors containing information that no satellites are visible.
-This test provided and confirmed that the smart phones are always performing a
+This test confirmed that the smart phones are always performing a
postion estimation at the moment when an RRLP request is sent to the MS.
-The last test has been performed outside of the computer pool building.
+The last test has been carried out outside of the computer pool building.
This test was conducted to confirm the argument that precision of the estimated
position is related to the received GPS signal strength and number of visible satellites.
As it can be seen in figure \ref{img:googlemapsResults}, the tests were performed
at the blue dot and around it and the estimated positions were 1-5 m off of
-the real position. The estimated positions are shown in a blue rectangle with an O
+the real position. The estimated positions are shown in a blue rectangle with an O (letter O)
in the left corner of it.
-\newpage
+
\begin {table}[hb!]
-\caption{Smart phone RRLP test results}
+\caption{Smart phone RRLP test results from Test room 2.}
\label{tbl:resultsByTest}\centering
%\rowcolor{2}{light-gray}{}
\scriptsize\fontfamily{iwona}\selectfont
@@ -2694,7 +2695,7 @@ $Defy$&No&No&No&No response (time out) \\\midrule
$iPhone$ $4$&No&No&No&Reference time, Navigation Model,\\
&&&&Reference Location\\\midrule
$iPhone$ $3GS$&Yes&Yes&No&/\\\midrule
-$G1$&No&Yes&Sometimes&/\\\midrule
+$G1$&No&Yes&Only occasionallys&/\\\midrule
$Galaxy$ $S2$&No&No&No&Acquisition Assistance\\\midrule
$Galaxy$ $S3$&No&No&No&Reference Location, Reference Time,\\
&&&&Acquisition Assistance, Navigation Model\\\midrule
@@ -2707,60 +2708,61 @@ $Blade$&No&No&Yes&/
\end {tabular}
\end {table}
-In table \ref{tbl:resultsByTest}, the list of all results is shown. The abbreviations
+In table \ref{tbl:resultsByTest}, the list of all results from Test room 2 is shown. The abbreviations
used in the table are explained in this paragraph. RRLP indicates the MS has delivered its
position only when an RRLP position request without any assistance data has been sent.
RRLP(E) indicates the MS has delivered its position only when an RRLP request contained
almanac, ephemeris, UTC model, ionospheric model and reference location data has been sent.
-RRLP(A) indicated the MS has delivered its position only when an RRLP request contained
-almanac, UTC model, ionospheric model and reference location data has been sent (the difference
-from RRLP(E) is in the fact that no ephemeris data are included). If there is no error description
-then the stated data were requested to be delivered to the MS. If the position was delivered the
-position estimation by the smart phones took never longet than 3 minutes. The waiting time period
-of 3 minutes for the result is not discouraging provided that the assistance data like
+RRLP(A) indicates the MS has delivered its position when an RRLP request contained
+only almanac data. If there is no error description, then the smart phone delivered its position
+successfully. Otherwise, the stated data were requested by the smart phones. In case the positions
+were delivered by the smart phones, the waiting period was usually shorter than 3 minutes.
+The waiting time period of 3 minutes for the result is not discouraging provided that the assistance data like
reference time (exact time, explained in section \ref{sec:rrlpassistance}) and
-acquisition assistance data (phase and Doppler effect frequency required by the AGPS,
+acquisition assistance data (phase shift and Doppler effect frequency required by the AGPS,
explained in section \ref{sec:rrlpassistance}) were not delivered to the MS. It is important
-to mention the strange behaviour by $Galaxy$ $Nexus$ $i9250$, the MS responded only with
+to mention the strange behaviour by $Galaxy$ $Nexus$ $i9250$, the smart phone responded only with
acknowledgements while the assistance data have been sent but after the reception it
immediatelly closed the SDCCH channel. The $Blade$ closed the SDCCH channel after 4 transmitted
assistance packets for the RRLP(E) test. The $Defy$ by Motorola did not produce any output at
-all and behaved like a 2G cell phone without a GPS receiver. To eliminate any doubts and
-suspicion if the SDCCH channel was properly working and not producing the time outs,
-2G phones (Nokia 3310 and Siemens M50) have been used to perform tests. An SDCCH channel
-has been initialized 10 times at different days with the 2G phones and left open for 10
+all and its behaviour was exact like of an 2G cell phone without a GPS receiver.
+To eliminate doubts and suspicion if the SDCCH channel was properly working and the
+generated time outs were not by OpenBSC, 2G phones (Nokia 3310 and Siemens M50)
+have been used to perform the SDCCH test. An SDCCH channel
+has been initialized 10 times on different days with the 2G phones and left open for 10
minutes. The 2G phones reported the signal strengths of the initialized channel according
-to the defined standard. This provides a proof for the cases where the time out appeared,
-it was not produced by the BTS but rather by the smart phone. One important remark related
-to the tests ought to be mentioned. While the $iPhone$ $3GS$ and $G1$ provided the results in
-the tests, sometimes it was the case they did not deliver the results the first time
-the RRLP request was executed but an time out. Second time the same RRLP request was sent,
-the smart phones delivered their positions. This unexpected behaviour raises a suspicion that
+to the defined standard. This provides a proof that if time outs were generated, they were
+generated by the smart phones rather than OpenBSC. One important remark related
+to the tests has to be mentioned.
+Occasionally, $iPhone$ $3GS$ and $G1$ did not deliver their results the first time the RRLP
+request was sent but an time out which lead to the disconnection of the SDCCH channel.
+Second time the same RRLP request were sent, the smart phones delivered their positions.
+This unexpected behaviour raises a suspicion that
the smart phones do not behave according to the RRLP standard where it is well defined how much
time they have to perform the localization. However, the previous statement ought to be considered
-with some uncertainty since it can not be proved without access to the firmware of the smart phones.
-The combination of described findings in this chapter and in table \ref{tbl:resultsByTest}
+with some uncertainty since it can not be proved without access to the hardware and firmware
+of the smart phones. The combination of described findings in this chapter and in table \ref{tbl:resultsByTest}
provides some support for the premise that the RRLP standard is not yet a fully implemented
-standard by all the manufacturers that claim AGPS functionality. Does it depend on the AGPS chipset
-or RRLP itself, remains an open question.
+standard by all manufacturers that claim AGPS functionality. Does the RRLP functionality depend
+on the AGPS chipset or RRLP itself, remains an open question.
\section{Criticism of performed tests}
Perhaps the most serious weakness of the presented results
-is that the author had no access to the firmware of the MS while the
+is that the author had no access to the firmware or the hardware of the MS while the
tests have been performed. This would allow the author to see what type
and how the assistance data are employed by the AGPS in the MS. If access
could be gained, to the internal operation of the AGPS receiver,
all doubts and bias about the deduced hypotheses could be eliminated.
The whole system represents a black box where an input is
delivered and an output is expected. Another drawback was the lack of
-hardware information about the hardware inside of the MS (AGPS receivers and
+hardware information inside of the MS (AGPS receivers and
antennas). This does not allow an exact comparison between different
cell phone models and if they can acquire any GPS signal in weak signal
-strength conditions.
+strength conditions like it was in Test room 3.
Difficulties arise in assessment and comparing the results in this
thesis with other relevant studies due to the lack of any research
-studies compleyed using the equivalent hardware and type of
+studies completed using the same hardware and equivalent type of
assistance data. In the relevant studies different
hardware test equipment is used while this thesis was carried
out without that test equipment \citep{gpsTest2}.
@@ -2769,47 +2771,51 @@ time required to get a position response from a MS where only
almanac, ephemeris, UTC model, ionospheric model and reference
location data have been delivered to the MS.
-Another limitation of the evaluated results lies in the fact that it has
-only been applied to the stated cell phones and it could not be tested
+Another limitation of the evaluated results lies in the fact that the tests have
+been only applied to the stated cell phones and it could not be tested
with all possible models. The tests suffer from a major drawback as real time
movement of satellites, the tests could not be conducted parallely but
-rather in serial manner in time. In other words a satellite visible at
+rather in serial manner in time. In other words, a satellite visible at
the moment while the first test is being performed may not be visible
the second time when the test is executed. The tests were performed
in the morning 10:00-12:00 and in the afternoon 16:00-19:00, with
morning being the period of day when it was difficult even for the external
-GPS device to track the satellites. GPS signal strength is a vital
-measurement information, where the signal levels are lower than a
-predefined acquisition sensitivity even assistance data can not help.
+GPS device to track the satellites (by difficulty is meant the period of time
+required to get a position fix). GPS signal strength is vital for performing
+a position estimation due to the phase shift and Doppler frequencies. When
+the signal levels are lower than acquisition sensitivity of the GPS receiver
+inside the smart phone even assistance data can not help further.
Antenna polarization and the position of the cell phone matter as well.
Correctness of assistance data in almanac and ephemeris data can not be
verified. The author had to rely and trust the Navigation Center of the US Coast Guard and Trimble as sources
although errors were confirmed by different studies in \citep{Stanford-Ephem-Errors}
\citep{NASA-Ephem-Errors}. Errors can be confirmed by the author in
-ephemeris data as well (URA values were out of range specified by the standard).
+ephemeris data as well (URA values were out of specified range).
These errors were not continual but appeared occasionally and these errors
were inside of the assistance data provided by Navigation Center of the US Coast Guard (NVCS).
+Occasionally ephemeris data for some of the GPS satellites were missing as well.
\section{Future work}
\label{sec:futWork}
The system could be extended with a GPS device that delivers raw GPS data
instead of using the data provided by NVCS and Trimble. Obtained data by the GPS
-could be compared to the data provided by NVCS or other GPS observation stations
+receiver could be compared to the data provided by NVCS or other GPS observation stations
and verified for errors. By having more redundant sources of same information,
-mistakes in the output could be eliminated. More sources of redundant data could
-indicate the correctness of assistance data.
+mistakes in the GPS receiver output or transmission could be detected and eliminated since
+other sources of redundant data could indicate the correctness of assistance data.
Another idea to extend this work would be to use an LMU and provide the
reference time and acquisition assistance data. This feature would enhance the
-complete system. However, one ought to understand it would require great changes
+complete system. However, one ought to understand it would require large changes
in the OpenBSC source code and interoperability between the BTS and LMU.
-Additionally a position tracking system could be built. By adding a timer that will
+Additionally a position tracking system of GSM users could be built. By adding a timer that will
execute an RRLP request every few minutes. The successfully estimated positions could
-be connected into a path and displayed where the GSM user spends his time. Along the
-described method, a machine learning algorithm could be developed to predict the
-movement of GSM users \citep{predictMovements}.
+be connected into a moving paths. Along the suggested idea, a machine learning algorithm
+could be used to process the path data and to predict the movement of GSM users
+for specific weekdays \citep{predictMovements}. If the routes of the GSM users are known, the user
+could be warned to take another path.
%Tests could be performed if it possible if it can be tricked out by the software Dennis mentioned (protect my privacy)!
diff --git a/vorlagen/thesis/src/maindoc.lot b/vorlagen/thesis/src/maindoc.lot
index 3ebdceb..e37ce92 100644
--- a/vorlagen/thesis/src/maindoc.lot
+++ b/vorlagen/thesis/src/maindoc.lot
@@ -11,5 +11,5 @@
\addvspace {10\p@ }
\addvspace {10\p@ }
\contentsline {table}{\numberline {6.1}{\ignorespaces Smart phone models used for testing in the thesis.\relax }}{64}{table.caption.42}
-\contentsline {table}{\numberline {6.2}{\ignorespaces Smart phone RRLP test results\relax }}{68}{table.caption.45}
+\contentsline {table}{\numberline {6.2}{\ignorespaces Smart phone RRLP test results from Test room 2.\relax }}{68}{table.caption.45}
\addvspace {10\p@ }