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SmartCampusAAU APP

SmartCampusAAU APP. - Enabling Ubiquitous Positioning and Navigation Through Crowdsourcing. Motivation. GPS positioning and navigation has become commonplace , but GPS has severe problems inside buildings : GPS positions estimates are very coarse .

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SmartCampusAAU APP

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  1. SmartCampusAAU APP - EnablingUbiquitousPositioning and Navigation ThroughCrowdsourcing

  2. Motivation • GPS positioning and navigation has becomecommonplace, but GPS has severe problems insidebuildings: • GPS positions estimatesareverycoarse. • There is nosemanticinformation, i.e., information aboutrooms, escalators, printer facilities, etc. • There is noindoor navigation. • The SmartCampusAAUappaddressestheseshortcomings by providingindoorpositioningbasedon usercontributions and Wi-Fitechnology: • Positioningaccuracycanbe as good as three meters, depending on a variety of factors, including the amount of data supplied by users. • There is semantic information (ifusers have suppliedthis) • There is indoor navigation (ifusers have enabledthis)

  3. IndoorPositioning via Wi-Fi • SmartCampusAAUusesWi-Fitechnologywhen GPS signals areabsent. • Wi-Fiinfrastructuresareubiquitous and Wi-Fiis available in modernSmartphones • Thismeansthatindoorpositioning and navigation canbe made available in anybuilding to anyuser (carrying a Smartphone). • However, indoorpositioning is hard: WhenWi-Fi signals aretransmitted from an access point, theyareattenuated, scattered and reflected by obstacleslikewalls, furniture and evenpeople. • The result is highlyunpredictable signal propagationswhichmeansthattraditionallaterationtechniques have difficulties in providingaccurate position estimates • Instead, the most accuratetechnique is calledlocation fingerprinting. • The location fingerprintingtechnique is based on measuringactual signal strengths from access points. • The location fingerprintingtechnique is able to provide location estimateswithin 3 meters of a user’sactual position.

  4. How Location Fingerprintingworks • Location fingerprinting is split intotwophases: • Offline: • In order to makeindoorpositioningpossible, a so-calledradio map must firstbebuilt. • A radio map is a database thatcontains signal strength information for differentcoordinatesthroughout a building. • A radio map is incrementallybuilt in the followingway: • A user stands at a certain location and marks her location on a map. • The userthen starts measuring signal strengths for about 10 seconds. • Finally, the <location, measurement> information is saved in a server-side radio map. • Thisprocess is repeated at different locations until the entireindoorenvironment has beencovered by measurements. • Online: • If a radio map has beenbuilt, indoorpositioning is nowenabled. • A usercanbeestimated by the system to be at any of the locations whereusers have measured signal strengths in the offline phase.

  5. Location Fingerprinting- The Offline Phase Radio Map Signal strengthsaremeasured at the starred locations (x1, y1, z1) AP3 (x2, y2, z1) AP1 = -65 AP2 = -55 AP3 = -75 (x3, y3, z1) AP1 = -80 AP2 = -45 AP3 = -60 (x4, y4, z1) AP1 = -45 AP2 = -60 AP3 = -85 AP1 = -40 AP2 = -70 AP3 = -95 … (…) AP1 AP3

  6. Location Fingerprinting- The Online Phase Radio Map The usercanbeestimated to be at any of the starred locations AP1 = -55 AP2 = -40 AP3 = -80 (x1, y1, z1) AP3 AP1 = -40 AP2 = -60 AP3 = -95 (x2, y2, z1) AP1 = -40 AP2 = -70 AP3 = -85 (x3, y3, z1) AP1 = -35 AP2 = -90 AP3 = -55 (x4, y4, z1) AP1 = -50 AP2 = -40 AP3 = -85 … (…) AP1 AP2

  7. SmartCampusAAU • The SmartCampusAAUappimplements the location fingerprintingtechnique as described on the previouspages. • In the offline phase, the SmartCampusAAUappcanbeused to build a radio map. • Moreover, in the offline phaseuserscanbuild a graph of the indoorenvironment (establishing links between locations). • The graphcanbeused to enableindoor navigation. • (The graph is alsoused to improve the positioningaccuracy) • In the offline phase, userscanalsosupplysemantic information aboutlocations.

  8. Walkthrough of the SmartCampusAAUapp • The SmartCampusAAUappcanbeused to enableindoorpositioning in a building via the location fingerprintingtechnique. • The remaining pages detailshowthis is accomplished. • First, wedescribe the offline activitiesthatarerequired to enable the online positioning and navigation functionality: • Add a building and buildingfloors(thisonlyneeds to be done once) • Build a radio map– to enableindoorpositioning • Supplysemantic (i.e., human readable) information. • Builda graph – to enableindoor navigation (The ”Offline Mode” is accessed by choosingMENU->Offline Modewhen the app starts)

  9. 1-a) Add new building (3) (1) (2)

  10. 1-a) Add a new building • The veryfirst step is to add a new building to the system • This is onlyneeds to be done once (whenno radio mapexists) by the veryfirstcontributor. • A buildingshouldbe given a readablename, e.g., ”Empire State Building” and an optional (official) url. • The buildingshouldthenbepositionedglobally by markingits location on Google Maps. • The system willsuggest an appropriateaddress.

  11. 1-b) Add/Editbuildingfloors EditFloor New Floor (1) (2)

  12. 1-b) Add/editbuildingfloors • The second step is to addfloors to the building • Even if a buildingonly has onefloor it must still beadded to the system. • In the Offline Mode, chooseMENU -> Edit Graph -> Edit Building Floors. Thiswill bring up screen (1). • This shows the floorsthat have beenadded to the system. Youcannoweither: • Add a new floor • Edit an existingfloor • Whenaddingorediting a floor it must be given a floornumber as well as a floorname.

  13. 2-1) Addmeasurement (extendorupdate the radio map) Addmeasurement to new location Addmeasurement to existing location (1) (2)

  14. 2-1) Addmeasurement (extendorupdate the radio map) • Whenyouare in the Offline Mode youcansee a number of icons – theseiconsrepresent the placeswhereotherusers have measured signal strengths(and hence, locations where the system canestimateusers to be). • Youcanadd a new location to the radio map by clicking a location on the map and choosingMENU-> Measure. • Youcanfine-tune the location by choosingMENU->EnableD-pad. Thiswill give you a little joystick to nudge the location up, downorsideways. • Make sure thatyou have choosen the correctfloor (MENU-> ChangeFloor) • Youcanalsoupdatean existing location by clickingitsiconand choosing ”New Measurement”. Updatingexisting locations willhelp to continuouslyimproving the positioningaccuracy of the system. • IMPORTANT! Make sure you stand in the location you marked on the map.

  15. 2-2) Measuring signal strengths (1) (2) (3)

  16. 2-2) Measuring signal strengths • Whenyou have opted to measure signal strengths at a location youarebrought to screen (1) on the preceeding page. • It is importantthatyouremain in the position thatyou marked on the mapduring the measurementprocess. • You start a measurement by clicking the ”Start” button. • Thiswillwill up a dialog that shows the number of Wi-Fiscansthat have currentlybeenperformed. • The measurementprocess is stopped by clicking ”Stop”. • The more scansyoutakebeforeclick ”stop” the better. Werecommend a minimum of 10 scans, but even more scanswill have a beneficieleffect on the positioningaccuracy of the system. • When the measurementprocess is done a list of access points thatcouldbeheard is shown. • If youknowthatsomeaccess points do not belong to the building, pleaseunmarkthem. Otherwise, just leave all access points marked. • The final step is to save the measurement by clicking the ”UploadSelected” button.

  17. 3) Addsemantic information (1) (2) (3)

  18. 3) Addsemantic information • When a new location has beenadded to the radio mapyouwillnoticethat it is represented by a ?-icon on the map. • Thismeansthat the system is nowable to position users at that location. • Youcanalsoassociatesemantic information (i.e., human readable information) by clicking on the location and choosing ”Edit Location”. Thiswill bring you to screen (1) on the preceedingpage. • Youcanspecify the followingdetails for a location: Title, description and url for the location. Youshould mark the field ”Is Entrance” if the location represents an entranceinto the building • Youcanspecifysomeproperties for the location (e.g., whether the location is an office, lectureroom, etc.). Thiswillbereflected in the iconthat is shown for the location • This shows an example of havingaddedsemantic information to a location. The location’stitle is ”Canteen”, the descriptionsays ”Open 11-13” and there is a URL whichwill show furtherdetails for canteen. The location was marked as ”Food” which shows in the icon.

  19. 4) Add links (1) (2) (3)

  20. 4) Add links • In order to enableindoor navigation youneed to add links betweenneighbouring locations where it is physicallypossible to movebetween. • In the Offline Mode youchooseMENU->EditGraph->Edit Links. • Youadd a link by clicking on twoneighbouring locations thatare not yetconnected and thenchooseMENU->Add Link. Thiswill bring you to screen (2) • On this screen youspecifyproperties for the link. ”None” meansthattherearenospecialproperties; otherwiseyoucanindicatewhether the locations areconnected via an elevator orstairs. • This shows a link that is nowconnectiontwo locations. • The procedure for removing a link is identicalexceptyoushouldclickon two locations thatarealreadyconnected and thenchooseMENU->Remove Link.

  21. Online Mode • Assuming the four steps in the Offline mode have been done, indoorpositioning and navigation is nowenabled in the building. • When the SmartCampusAAUapp starts up it is in the online modewhereindoorpositioning and navigation functionalitycanbeused. • The following pages demonstrate the online functionality.

  22. IndoorPositioning – ChooseProvider

  23. IndoorPositioning – ChooseProvider • In MENU->ChooseProvideryoucanchoosebetweendifferent location providers: • GPS: Uses GPS for positioning. Appropriate for outdoorusage. • Wi-Fi: UsesWi-Fi (location fingerprinting) for positioning. Appropriate for indoorusage. • Whenswitching to Wi-Fi, the system willdetect and download an appropriate radio map and then start positioning. The system willautomaticallychangefloorswhen the user’scurrent location changesfloor. • None: Turnsoffpositioning. Appropriate for savingenergywhenpositioning is not needed.

  24. Online Options • MENU contains the available online options • Youcanseewhich points of interestareavailable on the currentfloor, youcansearch for points of interest, and youcanchangefloor.

  25. Tracking Position On/Off Trackingenabled Trackingdisabled Trackingmeansthat the themapwill center around the user’scurrent position. Trackingcanbedisabled by panning on the maporchangingfloor from the menu. Also, the trackingbutton in top leftcornercanbeused to enable/disabletracking

  26. Navigation

  27. Summary • The SmartCampusAAUapprelieson end user participation (akacrowdsourcing) to enableindoorpositioning and navigation. • Usersenableindoorpositioning via location fingerprinting • Usersenableindoor navigation by adding links between locations. • Userssupplysemantic information aboutindoorlocations

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