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authorRefik Hadzialic2012-06-26 13:32:25 +0200
committerRefik Hadzialic2012-06-26 13:32:25 +0200
commit6f8cd5e9b91df791b4db87dbe1296249587ab23c (patch)
tree08c2bfa2a8015f669345599e2cd75c7131a22c70
parentWriting about A-GPS (diff)
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GPS Ranging write
-rw-r--r--vorlagen/thesis/maindoc.pdfbin4684710 -> 4688247 bytes
-rw-r--r--vorlagen/thesis/src/bib/literatur.bib24
-rw-r--r--vorlagen/thesis/src/kapitel_x.tex44
-rw-r--r--vorlagen/thesis/src/maindoc.tex4
4 files changed, 52 insertions, 20 deletions
diff --git a/vorlagen/thesis/maindoc.pdf b/vorlagen/thesis/maindoc.pdf
index 0282599..f60c574 100644
--- a/vorlagen/thesis/maindoc.pdf
+++ b/vorlagen/thesis/maindoc.pdf
Binary files differ
diff --git a/vorlagen/thesis/src/bib/literatur.bib b/vorlagen/thesis/src/bib/literatur.bib
index 5b9b730..2488135 100644
--- a/vorlagen/thesis/src/bib/literatur.bib
+++ b/vorlagen/thesis/src/bib/literatur.bib
@@ -82,7 +82,7 @@
}
@BOOK{understandGPS,
- title = {{Understanding GPS : principles and applications}},
+ title = {{Understanding GPS: principles and applications}},
publisher = {Artech House},
year = {2006},
author = {{Elliott D. Kaplan}, Christopher Hegarty},
@@ -177,13 +177,6 @@
school = {California Institute of Technology}
}
-@ARTICLE{kopka1997latex,
- author = {Kopka, H.},
- title = {{LATEX Band 1: Einf{\"u}hrung}},
- year = {1997},
- publisher = {Addison-Wesley}
-}
-
@MISC{openbscInstall,
author = {osmocom},
title = {{OpenBSC build guide}},
@@ -295,4 +288,17 @@ ISSN={0018-9162},}
issue = {3},
note = {10.1007/s10291-002-0028-0},
year = {2002}
-} \ No newline at end of file
+}
+
+@INPROCEEDINGS{998892,
+author={Akopian, D. and Syrjarinne, J.},
+booktitle={{Position Location and Navigation Symposium, 2002 IEEE}},
+title={{A network aided iterated LS method for GPS positioning and time recovery without navigation message decoding}},
+year={2002},
+month={},
+volume={},
+number={},
+pages={ 77 - 84},
+keywords={ GPS positioning recovery; GPS time recovery; LS iterations; SV orbit positions; navigation message decoding; network aided iterated LS method; network aided iterated least squares method; positioning; receiver tracking side measurements; satellite position variable; satellite pseudorange estimates; satellite transmission time estimates; satellite vehicle navigation message; time-of-week information; Global Positioning System; distance measurement; iterative methods; least squares approximations; parameter estimation; radio receivers;},
+doi={10.1109/PLANS.2002.998892},
+ISSN={},} \ No newline at end of file
diff --git a/vorlagen/thesis/src/kapitel_x.tex b/vorlagen/thesis/src/kapitel_x.tex
index 6821449..7d5b479 100644
--- a/vorlagen/thesis/src/kapitel_x.tex
+++ b/vorlagen/thesis/src/kapitel_x.tex
@@ -104,7 +104,7 @@ t=t_{SV}-\Delta t_{SV}
Nevertheless, the broadcast satellite time
information is not sufficient to estimate the precise
time at the moment of the signal arival. Even though the signal
-arives in approximately\footnote{Propagation time
+arrives in approximately\footnote{Propagation time
depends on user and GPS satellite position.} $77 \, ms$,
the precision of the atomic clock is in the
range of 10 ns \citep[Chapter 2]{diggelen2009a-gps}.
@@ -140,7 +140,7 @@ motion of the two bodies, transmitter and
receiver, towards or away from each other and causes
frequency shift of the electromagnetic wave
\citep[Chapter 4]{3540727140}.}
-and wave propagation, the transmitted signal arives
+and wave propagation, the transmitted signal arrives
phase disordered at the receiver \citep{4560215}.
This phase disorder is a consequence of the relationship
between the instantaneous frequency and instantaneous phase
@@ -516,6 +516,11 @@ In the same way works the hot start, only the time is precisely
known in accuracy of submilliseconds.
\section{Distance and position estimation}
+This section will focus on examining the distance and position estimation inside of the GPS system.
+GPS system, as mentioned earlier, takes advantage of the time of arrival (TOA) ranging concept
+to determine user position. Time is measured how long it takes for a signal to arrive from a
+known location. Satellite locations can be estimated using the ephemeris data and the exact time.
+
\section{Assisted GPS in Wireless networks}
\label{sec:agps}
@@ -526,12 +531,11 @@ 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. The basic scenario can be seen in figure \ref{img:agpsPrinciple}.
+with an A-GPS receiver. The basic scenario can be seen in figure \ref{img:agpsPrinciple}.
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
-
+approximate location, satellite clock corrections, ephemeris and navigation data
\citep{springerlink:10.1007/s10291-002-0028-0}.
\begin{figure}[ht!]
\centering
@@ -543,7 +547,7 @@ approximate location, satellite clock corrections, ephemeris and navigation data
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
+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
@@ -553,20 +557,38 @@ Conventional GPS receivers require at least up to extra $18$ to $30\,s$ to recei
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
+$-130 \,\mathrm{dB}$ 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[Chapter 2]{diggelen2009a-gps}.} (located near ground) at worst normal orientation''
\citep{GPS-Interface-Specification}.
-
+A simplified A-GPS algorithm given in \citep{springerlink:10.1007/s10291-002-0028-0} will be presented here. This
+algorithm benefits in speed the more assistance data is present. As the first satellites are tracked,
+the A-GPS algorithm has an estimation of the feasible region where the target A-GPS user might be located.
+Consequently, this feasible region will shrink until the location has been fully estimated
+\citep{springerlink:10.1007/s10291-002-0028-0}.
+ \begin{enumerate}[(i)]
+ \item Visible satellites and their positions are identified and computed out of the delivered ephemeris
+ and time data.
+ \item For each visible satellite $SV_i$, the code phase, $\tau_i$, is estimated.
+ \item Pseudoranges are calculated for each visible satellite $SV_i$.
+ \item Triangulate the position out of the pseudoranges $\rho_i$.
+ \end{enumerate}
+Although the A-GPS algorithms can be seen as a set of equations, with more unknowns terms known it is
+straightforward to solve the set of equations. However, with more of the unknown terms it takes more
+time to get (decode) them from the satellite messages. One should know various A-GPS algorithms exist,
+some do not require the exact time component and navigation data to be present in the assistance data
+\citep{998892}.
+
+\section{Error estimation}
\chapter{Radio Resource Location Protocol}
\chapter {Working}
\section{Zitieren..}
-citep: \citep{kopka1997latex} \\
-citet: \citet{kopka1997latex}
+citep: \citep{multipleTRX} \\
+citet: \citet{multipleTRX}
\chapter{System}
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diff --git a/vorlagen/thesis/src/maindoc.tex b/vorlagen/thesis/src/maindoc.tex
index 33f5f73..82839e6 100644
--- a/vorlagen/thesis/src/maindoc.tex
+++ b/vorlagen/thesis/src/maindoc.tex
@@ -103,6 +103,10 @@ stepnumber=1, numbersep=5pt, numbers = none}
% Index
\usepackage{makeidx}
+% USED FOR ENUMERATION
+\usepackage{enumerate}
+
+
% Todonotes: Paket zum schreiben von Notizen zu konkreten Textstellen
% siehe: http://mirror.ctan.org/macros/latex/contrib/todonotes/todonotes.pdf