Naam, Afdeling 07/01/2009 To localise or to be localised with Wi-Fi in the Hubei Museum? Edward Verbree, Sisi Zlatanova, Karl van Winden, Eva van der Laan, Antigoni Makri, Li Taizhou, Ai Haojun
Introduction MSc Geomatics - DaRen Syntheses Project Hubei Provincial Museum – Wuhan China Localisation Wi-Fi Fingerprinting Wi-Fi Monitoring Wi-Fi Monitored Fingerprinting
Introduction The overall goal of the project is to investigate the potential of a 3D indoor navigation systems and raise awareness of the possibilities provided by the technology for every-day users. This goal is achieved by creating a 3D multi-purpose indoor navigation application named DaRen Chinese words Da “intelligence, accessibility” and Ren “people”
Hubei Provincial Museum
Application Navigation Localisation Routing Visualisation
Localisation Research Question What are the possibilities of Wi-Fi monitoring in comparison to the commonly known fingerprinting method for the purpose of a 3D indoor navigation system?
Localisation Granularity Localisation ≠ (Point) Positioning Localisation = Place oriented (floor, room, exhibition) Localisation = Needed as starting place for routing Localisation = Needed for location based services (sec)
Wi-Fi Fingerprinting Existing WLAN-infrastructure can be used Every second a location can be given No privacy issues regarding storage of locations 1.Measurements of Signal Strength Reference Points 2.Creation of Radio Map 3.Location Determination
Reference Points
Measuring Procedure Offline / Training Phase: Measurements RSS have been performed in 4 directions Time of measuring: 1 minute / direction Creating probability radio map: Consists of mean value and standard deviation Online / Localisation: Calculating the most probable location
Wi-Fi Fingerprinting Results High Spatial Resolution of Reference Points + Probabilistic RSS values = Accurate Localisation Wuhan University
Wi-Fi Fingerprinting Limitation Device driven (Wi-Fi scanning) Apple devices excluded ‘Space segment’ (Wi-Fi Access Points) not under control Access Point re-configuration requires update of radio map
Wi-Fi Monitoring Meshlium Xtreme
Wi-Fi Monitoring Beacon frames Send by ALL mobile devices (smartphones, laptops, etc.) in order to connect to Access Point Iff Wi-Fi is on (Free Internet in Museum) Device doesn’t have to be connected Wi-Fi Monitor – Meshlium Xtreme: Receives and stores MAC-address, Strength of Signal Indicator (%), Timestamp (Date/Time), Vendor (Apple, Samsung, Nokia, etc) Advantages No additional application is required to acquire RSSI Data can be stored at an external database, which can be used to provide information to museum and users every moment of the day
Wi-Fi Monitoring Applications Localisation Proximity (near) to Wi-Fi monitor Distance to monitor RSSI gives indication in ‘open’ space Wi-Fi Monitored Fingerprinting possible Business information Count of (Wi-Fi enabled) visitors Time spent at exhibation Direction of movement of visitors (with two or more monitors) Crowd control No need of installed app, no user-involvement
Wi-Fi Monitoring Limitation Relies on probe request frames of devices Interval between two successful scans can be large Not all mobile devices were scanned Newer types of devices > update of firmware of monitor Privacy Issues: Renew Recycling Bins “City of London bans data-collecting Wi-Fi smart bins
Wi-Fi Monitored Fingerprinting Test Two Meshlium Xtreme Wi-Fi Monitors part of Access Point configuration while creating radio-map Correlation determined between RSSI (Monitor) and RSS (devices) RSSI Radio Map created for each Monitor
Wi-Fi Monitored Fingerprinting RSSI Radio Map First monitor
Wi-Fi Monitored Fingerprinting Where am I?
RSSI ‘Distance’ to First Monitor
RSSI ‘Distance’ to Second Monitor
Wi-Fi Monitored Probability map
To localise or to be localised Conclusions To localise (to sniff) App needed at devices (if possible) Happy few (early adopters) Wi-Fi infrastructure not under control for localisation purposes or To be localised (to be sniffed) Web-application can be used at devices Everyone (Free Internet) Dedicated Wi-Fi-Monitors under control for localisation purposes