some new TeX aspects

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2016-02-05 20:20:52 +01:00
parent 593f4d582b
commit 9e9b6882cd
4 changed files with 79 additions and 7 deletions

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@@ -95,6 +95,7 @@
\newcommand{\percent}{\%} \newcommand{\percent}{\%}
\newcommand{\decibel}{dB} \newcommand{\decibel}{dB}
\newcommand{\dB}{dB} \newcommand{\dB}{dB}
\newcommand{\hpa}{hPa}
\newcommand{\degree}{\ensuremath{^{\circ}}} \newcommand{\degree}{\ensuremath{^{\circ}}}
% missing math operators % missing math operators

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@@ -8,7 +8,56 @@
route calculation, user checking the route) we use the average of all barometer readings during this route calculation, user checking the route) we use the average of all barometer readings during this
timeframe as realtive base $\overline{\mPressure}$. timeframe as realtive base $\overline{\mPressure}$.
During each transition from $\mStateVec_{t-1}$ to $\mStateVec_t$, the predicted pressure $\mStatePressure$ is
adjusted according to the resulting $z$-change, if any:
\begin{equation}
\mState_{t}^{\mStatePressure} = \mState_{t-1}^{\mStatePressure} + \Delta z \cdot \SI{0.105}{\hpa}
,\enskip
\Delta z = \mState_{t-1}^{z} - \mState_{t}^z
.
\end{equation}
\subsection{Wi-Fi \& iBeacons} \subsection{Wi-Fi \& iBeacons}
For additional absolute location hints, we use the Smartphones Wi-Fi and iBeacon sensor to measure the signal-strengths
of nearby transmitters. As the positions of both \docAP{}s and and \docIBeacon{}s are known beforehand, we compare
each measurement with its corresponding signal strength prediction which is defined by the 3D distance $d$
and the number of floors $\Delta f$ between the \docAPshort{} and the particle
\begin{equation}
P_r(d, \Delta f) = \mTXP - 10 \mPLE \log_{10}{\frac{\mMdlDist}{\mMdlDist_0}} + \Delta{f} \mWAF,
\end{equation}
and calculate the resulting probability as described in \cite{ipin2015}:
\begin{equation}
\mProb(\mObsVec \mid \mStateVec)_\text{wifi} =
\prod\limits_{i=1}^{n} \mathcal{N}(\mRssi_\text{wifi}^{i} \mid P_{r}(\mMdlDist_{i}, \Delta{f_{i}}), \sigma_{\text{wifi}}^2).
\label{eq:wifiTotal}
\end{equation}
For the \docWIFI{} component we thus need two parameters per \docAPshort{}: $\mTXP$ measured at a distance
$\mMdlDist_0$ (usually \SI{1}{\meter}) and the path-loss exponent $\mPLE$ describing the environment.
To reduce complexity and system setup time, we use the same values for all \docAP{}s at the cost of accuracy.
While, $\mTXP$ is best determined using averaged measurements at a single location,
a good estimation of $\mPLE$ requires several measurements and numerical optimization \cite{etwas_aus_der_MA}.
$\mPLE$ is thus chosen empirically.
For the \docIBeacon{} component we also use \refeq{eq:wifiTotal} but $\mTXP$ is transmitted by each beacon.
Again, $\mPLE$ is determined emprically. \todo{faellt hier meist kleiner aus, weil ja kuerzere reichweite etc}
\subsection{Step- \& Turn-Detection} \subsection{Step- \& Turn-Detection}
To prevent degradation within the particle-filter \cite{??} due to downvoting of particles with increased
heading deviation, we incorporate the turn-detection as control-data directly into the transition
$p(\mStateVec_{t} \mid \mStateVec_{t-1}, \mObsVec_{t-1})$.
\cite{thrun?}\cite{lukas2014?} to get a more directed sampling instead of a truly random one.
\commentByFrank{todo: wie wird die unsicherheit in der transition eingebracht, sigma, ..}

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@@ -1,7 +1,24 @@
\section{Indoor Localisation System} \section{Recursive Density Estimation}
\subsection{Overview} \commentByFrank{particle-filter wie bei lukas mit $\vec{o}_{t}$ in transition und $\vec{q}_{t-1}$ in eval??}
\commentByFrank{brauchen wir in der observation ueberhaupt noch $q_{t-1}$??}
\commentByFrank{das ist die basis fuer unser system}
\subsection{Transition}
\subsection{Evaluation} \begin{equation}
p(\mStateVec_{t} \mid \langle \mObsVec \rangle_{t}) = \\
p(\mObsVec_{t} \mid \mStateVec_{t})
\int
p(\mStateVec_{t} \mid \mStateVec_{t-1}, \mObsVec_{t})
p(\mStateVec_{t-1} \mid \langle \mObsVec \rangle_{t-1}
d\mStateVec_{t-1}
\end{equation}
\begin{equation}
\mObsVec = (\mRssiVec_\text{wifi}, \mRssiVec_\text{ib}, \mObsHeading, \mObsPressure)
\end{equation}
\begin{equation}
\mStateVec = (x, y, z, \mObsHeading, \mStatePressure),\enskip
x,y,z,\mStatePressure \in \R
\end{equation}

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@@ -28,7 +28,12 @@
\newcommand{\mMovingAvgWithSize}[1]{\ensuremath{\text{avg}_{#1}}} \newcommand{\mMovingAvgWithSize}[1]{\ensuremath{\text{avg}_{#1}}}
\newcommand{\mPressure}{\rho} % symbol for pressure readings \newcommand{\mPressure}{\rho}
\newcommand{\mObsPressure}{\mPressure_\text{rel}} % symbol for observation pressure
\newcommand{\mStatePressure}{\hat{\mPressure}_\text{rel}} % symbol for state pressure
\newcommand{\mHeading}{\theta}
\newcommand{\mObsHeading}{\Delta\mHeading} % symbol used for the observation heading
\newcommand{\mStateHeading}{\mHeading} % symbol used for the state heading
%\newcommand{\docIBeacon}{iBeacon} %\newcommand{\docIBeacon}{iBeacon}