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authorRefik Hadzialic2012-06-24 16:12:50 +0200
committerRefik Hadzialic2012-06-24 16:12:50 +0200
commitd1debb5ca79aeba70671ba076984768c6ff5ebab (patch)
tree2a3bb3c7365febc0621f8a33cc0eea1a30716a24
parentWriting A-GPS and distance estimation (diff)
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Writing about A-GPS
-rw-r--r--vorlagen/thesis/maindoc.pdfbin4678351 -> 4684710 bytes
-rw-r--r--vorlagen/thesis/src/img/A-GPS.pdfbin208511 -> 208468 bytes
-rw-r--r--vorlagen/thesis/src/img/A-GPS.svg24
-rw-r--r--vorlagen/thesis/src/kapitel_x.tex32
4 files changed, 39 insertions, 17 deletions
diff --git a/vorlagen/thesis/maindoc.pdf b/vorlagen/thesis/maindoc.pdf
index 119fdfe..0282599 100644
--- a/vorlagen/thesis/maindoc.pdf
+++ b/vorlagen/thesis/maindoc.pdf
Binary files differ
diff --git a/vorlagen/thesis/src/img/A-GPS.pdf b/vorlagen/thesis/src/img/A-GPS.pdf
index 61ede54..e9aa00a 100644
--- a/vorlagen/thesis/src/img/A-GPS.pdf
+++ b/vorlagen/thesis/src/img/A-GPS.pdf
Binary files differ
diff --git a/vorlagen/thesis/src/img/A-GPS.svg b/vorlagen/thesis/src/img/A-GPS.svg
index 78e9d98..8e7d64b 100644
--- a/vorlagen/thesis/src/img/A-GPS.svg
+++ b/vorlagen/thesis/src/img/A-GPS.svg
@@ -10,7 +10,7 @@
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
- width="679.03223"
+ width="669.03223"
height="611.86493"
id="svg2"
version="1.1"
@@ -24,26 +24,26 @@
inkscape:pageopacity="0.0"
inkscape:pageshadow="2"
inkscape:zoom="1.1336753"
- inkscape:cx="342.5161"
- inkscape:cy="235.36552"
+ inkscape:cx="332.5161"
+ inkscape:cy="235.36551"
inkscape:document-units="px"
inkscape:current-layer="layer1"
showgrid="true"
objecttolerance="1"
gridtolerance="1"
guidetolerance="1"
- inkscape:window-width="1280"
- inkscape:window-height="996"
+ inkscape:window-width="1366"
+ inkscape:window-height="692"
inkscape:window-x="0"
- inkscape:window-y="0"
+ inkscape:window-y="24"
inkscape:window-maximized="1"
fit-margin-top="0"
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fit-margin-right="0"
fit-margin-bottom="0">
<inkscape:grid
- originy="-59.223639mm"
- originx="-5.8170163mm"
+ originy="-59.223642mm"
+ originx="-8.639238mm"
spacingy="0.1mm"
spacingx="0.1mm"
units="mm"
@@ -8860,7 +8860,7 @@
</rdf:RDF>
</metadata>
<g
- transform="translate(-20.611475,-230.64979)"
+ transform="translate(-30.611473,-230.64979)"
id="layer1"
inkscape:groupmode="layer"
inkscape:label="Layer 1">
@@ -12077,16 +12077,16 @@
<text
xml:space="preserve"
style="font-size:16px;font-style:normal;font-weight:normal;line-height:125%;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke:none;font-family:Sans"
- x="20.611475"
+ x="30.611473"
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sodipodi:linespacing="125%"><tspan
sodipodi:role="line"
id="tspan102532"
- x="20.611475"
+ x="30.611473"
y="811.41736"> A-GPS receiver </tspan><tspan
sodipodi:role="line"
- x="20.611475"
+ x="30.611473"
y="831.41736"
id="tspan102571">in a smart phone</tspan></text>
<text
diff --git a/vorlagen/thesis/src/kapitel_x.tex b/vorlagen/thesis/src/kapitel_x.tex
index 5adca42..6821449 100644
--- a/vorlagen/thesis/src/kapitel_x.tex
+++ b/vorlagen/thesis/src/kapitel_x.tex
@@ -251,7 +251,7 @@ The high frequency term, $(\omega_{1}+\omega_{2})$, can be filtered out using
a low-pass filter\footnote{A low-pass filter passes
low frequency signals and attenuates
high frequency signals. In other words, signals higher than the
-speciefied cutoff frequency of the low-pass filter, are cut off by reducing their amplitudes.}.
+specified cutoff frequency of the low-pass filter, are cut off by reducing their amplitudes.}.
Ideally, the difference of the angle frequencies is zero,
as in equation \eqref{eq:delaOmega}, since $\cos(\Delta \omega)=\cos(0)=1$
and the remaining left signal is only the C/A code multiplied
@@ -517,7 +517,7 @@ known in accuracy of submilliseconds.
\section{Distance and position estimation}
-\section{Assisted GPS}
+\section{Assisted GPS in Wireless networks}
\label{sec:agps}
In the following paragraphs Assisted GPS (A-GPS) will be presented and how it works.
A-GPS receivers work on a ``similar principle'' as warm/hot start on GPS receivers.
@@ -526,11 +526,13 @@ transfer medium is used to deliver the same type of information that are known
at a warm/hot start \citep{755159}, \citep{901174}, \citep{springerlink:10.1007/s10291-002-0028-0}.
In this work, the external transfer medium is air and the information are transfered using electromagnetic
waves. The existing GSM interface was utilised for the purpose of delivering the data to the smart phone
-with the A-GPS receiver.
+with the A-GPS receiver. The basic scenario can be seen in figure \ref{img:agpsPrinciple}.
-The BTS station is connected to the GNSS server, which is directly
-connected to the GPS reference station and .
+The BTS station is connected to the global navigation satellite system (GNSS) server, which is directly
+connected to the GPS reference station. The GPS reference station delivers the GNSS server exact time stamps,
+approximate location, satellite clock corrections, ephemeris and navigation data
+\citep{springerlink:10.1007/s10291-002-0028-0}.
\begin{figure}[ht!]
\centering
\includegraphics[scale=0.50]{img/A-GPS.pdf}
@@ -538,6 +540,26 @@ connected to the GPS reference station and .
\label{img:agpsPrinciple}
\end{figure}
+Time stamp is not used in GSM networks since it can be
+off by several seconds and would require additional equipment for synchronizing the network
+\citep{springerlink:10.1007/s10291-002-0028-0}, \citep{901174}. However in CDMA networks the time stamp is
+accurate to within $100 \, \mu s$ \citep{springerlink:10.1007/s10291-002-0028-0}.Approximate
+location is typically taken to be the location of the BTS from which the target A-GPS receiver
+acquires the assistance data. Ephemeris and navigation data obtained by the A-GPS receiver
+help it to estimate the positions of the satellites and they can greatly
+enhance the sensitivity of the receiver especially in urban environments \citep{springerlink:10.1007/s10291-002-0028-0}.
+
+Conventional GPS receivers require at least up to extra $18$ to $30\,s$ to receive and decode the navigation data
+and to generate a location fix \citep{springerlink:10.1007/s10291-002-0028-0}.
+The bit error rate associated with gathering and decoding data dramatically decreases since the acquired signals
+can be attenuated by $10$ to $20\, \mathrm{dB}$ indoors \citep{springerlink:10.1007/s10291-002-0028-0} of the nominal
+$-130 \,\mathrm{dB}$ on a $3\, dBi$ linearly polarized user receiving antenna\footnote{3 dBi antenna indicates
+an antenna with a gain of $3\, \mathrm{dB}$ with respect to an isotropic (omnidirectional) antenna
+\citep[Chapter 2]{diggelen2009a-gps}.} (located near ground) at worst normal orientation
+\citep{GPS-Interface-Specification}.
+
+
+
\chapter{Radio Resource Location Protocol}