[5599] | 1 |
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| 2 | \documentclass[10pt]{beamer}
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| 3 | \usetheme{umbc2}
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| 4 | \useinnertheme{umbcboxes}
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| 5 | \setbeamercolor{umbcboxes}{bg=violet!12,fg=black}
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| 6 |
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| 7 | \usepackage{longtable}
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| 8 | \usepackage{tabu}
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| 9 |
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| 11 | \newcommand{\be}{\begin{equation}}
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| 29 | \renewcommand{\d}{\mbox{d}}
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| 30 | \newcommand{\dspfrac}{\displaystyle\frac}
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| 31 | \newcommand{\nl}{\\[4mm]}
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| 32 |
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[5601] | 33 | \title{Processing GNSS Data in Real-Time}
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[5599] | 34 |
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| 35 | \author{Leo\v{s} Mervart}
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| 36 |
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[5601] | 37 | \institute{TU Prague}
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[5599] | 38 |
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[5601] | 39 | \date{Frankfurt, January 2014}
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[5599] | 40 |
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| 41 | % \AtBeginSection[]
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| 42 | % {
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| 43 | % \begin{frame}
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| 44 | % \frametitle{Table of Contents}
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| 45 | % \tableofcontents[currentsection]
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| 46 | % \end{frame}
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| 47 | % }
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| 48 |
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| 49 | \begin{document}
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| 50 |
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| 51 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 52 |
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| 53 | \begin{frame}
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| 54 | \titlepage
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| 55 | \end{frame}
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| 56 |
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| 57 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 58 |
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| 59 | \begin{frame}
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[5601] | 60 | \frametitle{Medieval Times of GNSS (personal memories)}
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| 61 |
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| 62 | \begin{description}
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| 63 | \item[1991] Prof. Gerhard Beutler became the director of the Astronomical Institute, University of
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| 64 | Berne. The so-called Bernese GPS Software started to be used for (post-processing) analyzes of
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| 65 | GNSS data.
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| 66 | \item[1992] LM started his PhD study at AIUB.
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| 67 | \item[1992] Center for Orbit Determination in Europe (consortium of AIUB, Swisstopo, BKG, IGN, and
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| 68 | IAPG/TUM) established. Roughly at that time LM met Dr. Georg Weber for the first time.
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| 69 | \item[1993] International GPS Service formally recognized by the IAG.
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| 70 | \item[1994] IGS began providing GPS orbits and other products routinely (January, 1).
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| 71 | \item[1995] GPS declared fully operational.
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| 72 | \end{description}
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| 73 |
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[5599] | 74 | \end{frame}
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| 75 |
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| 76 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 77 |
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[5601] | 78 | \begin{frame}
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| 79 | \frametitle{CODE-Related Works in 1990's}
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[5599] | 80 |
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[5601] | 81 | \begin{itemize}
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| 82 | \item The Bernese GPS Software was the primary tool for CODE analyzes (Fortran~77).
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| 83 | \item IGS reference network was sparse.
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| 84 | \item Real-time data transmission limited (Internet was still young, TCP/IP widely accepted 1989).
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| 85 | \item CPU power of then computers was limited (VAX/VMS OS used at AIUB).
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| 86 | \end{itemize}
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| 87 |
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| 88 | In 1990's high precision GPS analyzes were almost exclusively performed in post-processing mode.
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| 89 | The typical precise application of GPS at that time was the processing of a network of static
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| 90 | GPS-only receivers for the estimation of station coordinates.
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| 91 |
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| 92 | \end{frame}
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| 93 |
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| 94 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 95 |
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[5599] | 96 | \begin{frame}
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[5601] | 97 | \frametitle{Tempora mutantur (and maybe ``nos mutamur in illis'')}
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[5599] | 98 |
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[5603] | 99 | \includegraphics[width=0.7\textwidth,angle=0]{pp_vs_rt.png}
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[5602] | 100 |
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[5603] | 101 | \vspace*{-2cm}
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| 102 | \hspace*{6cm}
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| 103 | \includegraphics[width=0.4\textwidth,angle=0]{ea_ztd_21h.png}
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| 104 |
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| 105 |
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[5599] | 106 | \end{frame}
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| 107 |
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[5601] | 108 |
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[5599] | 109 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 110 |
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[5601] | 111 | \begin{frame}
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[5604] | 112 | \frametitle{O tempora! O mores!}
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[5601] | 113 |
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[5604] | 114 | \begin{itemize}
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| 115 | \item people want more and more \ldots
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| 116 | \item everybody wants everything immediately \ldots
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| 117 | \item \hspace*{2cm} and, of course, free of charge \ldots
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| 118 | \end{itemize}
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| 119 | \vspace*{5mm}
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| 120 | In GNSS-world it means:
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| 121 | \begin{itemize}
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| 122 | \item There are many new kinds of GNSS applications - positioning is becoming just one of many
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| 123 | purposes of GNSS usage.
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| 124 | \item Many results of GNSS processing are required in real-time (or, at least, with very small
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| 125 | delay).
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| 126 | \item GPS is not the only positioning system. Other GNSS are being established (for practical but
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| 127 | also for political reasons).
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| 128 | \item People are used that many GNSS services are available free of charge (but the development and
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| 129 | maintenance has to be funded).
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| 130 | \end{itemize}
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| 131 |
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| 132 | \begin{block}{But \ldots}
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| 133 | \end{block}
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| 134 |
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[5601] | 135 | \end{frame}
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| 136 |
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| 137 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 138 |
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| 139 | \begin{frame}
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[5604] | 140 | \frametitle{Nihil novi sub sole}
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[5601] | 141 |
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[5604] | 142 | Each GNSS-application is based on processing code and/or phase observations that may be expressed
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| 143 | as
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| 144 | \begin{eqnarray*}
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| 145 | P^i & = & \varrho^i + c\;\delta - c\;\delta^i + T^i + I^i + b_P \\
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| 146 | L^i & = & \varrho^i + c\;\delta - c\;\delta^i + T^i - I^i + b^i
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| 147 | \end{eqnarray*}
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| 148 | where
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| 149 | \begin{tabbing}
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| 150 | $P^i$, $L^i$ ~~~~~~~ \= are the code and phase measurements, \\
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| 151 | $\varrho^i$ \> is the travel distance between the satellite
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| 152 | and the receiver, \\
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| 153 | $\delta$, $\delta^i$ \> are the receiver and satellite clock errors, \\
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| 154 | $I^i$ \> is the ionospheric delay, \\
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| 155 | $T^i$ \> is the tropospheric delay, \\
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| 156 | $b_P$ \> is the code bias, and \\
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| 157 | $b^i$ \> is the phase bias (including initial
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| 158 | phase ambiguity).
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| 159 | \end{tabbing}
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| 160 |
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| 161 |
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[5601] | 162 | \end{frame}
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| 163 |
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| 164 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 165 |
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| 166 | \begin{frame}
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| 167 |
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[5604] | 168 | Observation equations reveal what information can be gained from processing GNSS data:
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| 169 | \begin{itemize}
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| 170 | \item geometry (receiver positions, satellite orbits), and
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| 171 | \item state of atmosphere (both dispersive and non-dispersive part)
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| 172 | \end{itemize}
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| 173 |
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| 174 | The observation equations also show that, in principle, GNSS is an
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| 175 | \textcolor{blue!90}{interferometric} technique -- precise results are actually always relative.
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| 176 |
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| 177 |
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[5601] | 178 | \end{frame}
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| 179 |
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[5599] | 180 | \end{document}
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