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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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10 | \newcommand{\ul}{\underline}
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27 | \newcommand{\dd}{\mbox{\footnotesize{$\nabla \! \Delta$}}}
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28 | \newcommand{\p}{\partial\,}
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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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33 | \title{Processing GNSS Data in Real-Time}
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34 |
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35 | \author{Leo\v{s} Mervart}
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36 |
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37 | \institute{TU Prague}
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38 |
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39 | \date{Frankfurt, January 2014}
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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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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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74 | \end{frame}
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75 |
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76 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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77 |
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78 | \begin{frame}
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79 | \frametitle{CODE-Related Works in 1990's}
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80 |
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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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96 | \begin{frame}
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97 | \frametitle{Tempora mutantur (and maybe ``nos mutamur in illis'')}
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98 |
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99 | \includegraphics[width=0.7\textwidth,angle=0]{pp_vs_rt.png}
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100 |
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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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106 | \end{frame}
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107 |
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108 |
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109 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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110 |
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111 | \begin{frame}
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112 | \frametitle{O tempora! O mores!}
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113 |
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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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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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140 | \frametitle{Nihil novi sub sole}
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141 |
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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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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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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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178 | \end{frame}
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179 |
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180 | \end{document}
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