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Indoor orientation and navigation in buildings and underground public transport is still a challenge. A key problem is the determination of the levels, e.g. floors and platforms, especially in environments with large amount of balconies and more or less levitating escalators, lifts and stairs. Another desired application is navigation or at least orientation in public undergrounds, which is missing due to missing common available sensors. GPS is not available in tunnels. Wifi cells are very unusual at least in the Berlin underground environment. Infrastructure based sensors and communication would be able to solve a personal navigation, but requires investments. With the introduction of barometer as a sensor in the Android 2.3 API and the first available Android mobile phones with build-in barometer sensors (Xoom and Galaxy Nexus), pressure can be used to calculate altitudes or even more relevant to measure pressure differences, e.g. between building levels and stations. This talk is intended to give and get a feeling about the given accuracy and robustness in relation to indoor positioning for buildings and undergrounds and should report about the ongoing, but already promising experiments.
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Indoor and underground orientation and navigation by using the barometer sensor
Elizaveta Karpakova, 3. Sem. Geoinformation Master mit Kaatz, Richter und Zimmermann (Geoality GbR), … und Prof. Dr. Roland-M. Wagner
Droidcon 2012, Berlin, Urania, 14.3.2012
Overview
1. Problem statement for indoor orientation & navigation
2. Application example: (Berlin) Underground
3. Approach with Barometer
4. Data-collection
5. Analysis
6. Conclusion
Beuth Hochschule für Technik Berlin – University of Applied Sciences 2
Problem statement for indoor orientation
Do you need an (outdoor) navigator?
1992: no
2012: yes
GPS is not usable for indoor orientation and positioning, other sensors are needed
Challenge: Change! More Change in indoor environment, e.g. fairs, cons
Some privacy aspects, e.g. indoormaps only for welcomed visitors and not for everybody in the net; => local infrastructure
Additional indoor information needed, e.g. pics, contact, time, location => e-flyer
An early project is: openfloormap.org
Beuth Hochschule für Technik Berlin – University of Applied Sciences 3
Application example: (Berlin) Underground
Beuth Hochschule für Technik Berlin – University of Applied Sciences 4
CC-At-By Ingo http://www.flickr.com/photos/30184910@N06
Undergrounds are used by million people every day
Many are tourists and need permanent orientation & navigation
Orientation needed also between stairs and stations
Frequent users might be interested e.g. for a wake-up app
Only a few underground operators offer an (open) interface
Approach with Barometer
Cell-id Positioning in Undergrounds allows to define the line and a position between 4-6 stations
Underground stations have different altitudes due to crossings and surface
Barometer / pressure measurement is robust and does not require much energy
Moving train pressure changefor station counting
Only deltas are needed
Absolute altitudecalculation with weather service
Beuth Hochschule für Technik Berlin – University of Applied Sciences 5
Data-collection
Specialized app to capture the context
Which line?
Which direction
Walking / Stairs
Train movement
Capturing of all smartphone available sensor data
Beuth Hochschule für Technik Berlin – University of Applied Sciences 6
https://play.google.com/store/apps/details?id=de.geoality.activitys
Analysis: Characteristics I
Multiple underground train stations with filter
Beuth Hochschule für Technik Berlin – University of Applied Sciences 7
Filtered Pressure
Sensor Pressure
Analysis: Characteristics II
Beuth Hochschule für Technik Berlin – University of Applied Sciences 8
Underground Station
Pressure changes due to tunnel effects
Conclusion
Cellid positioning offers the underground line and an interval between 4-6 stations, which is not suficient
Acceleration and pressure changes are characteristic enough to count stations
Pressure Delta between (multiple) stations can additional be used for absolute positioning
Very robust for determination of levels (underground stairs, buildings)
Currently only two android devices available (Xoom, Galaxy Nexus)
Apps, Data and Bachelor Thesis available
Beuth Hochschule für Technik Berlin – University of Applied Sciences 9