Mobile Navigation With SVG Christian Schmitt SVG Open 2005

Contents  Introduction  Contents  Indoor positioning systems  Pathfinding + Map generator  Map viewer + navigation  Demo  conclusion

Indoor Positioning Technologies Overview  Infrared (IR)  Wireless LAN (WLAN)  Ultra-wide band (UWB)  Hybrid solution

Infrared Principle/Features  IR beacons sending a specific code.  Directed connection.  Range: cm  Accuracy: see range Advantages  Universal  Inexpensive  Basic technology Disadvantages  Line of sight required  Does not scale very well  Maintenance costs

WLAN Principle/Features  Fingerprinting based on signal strength measurements  Accuracy: 3-7 meters Pros  Use of existing WLAN infrastructure  Most PDAs have WiFi. WiFi tags  Easy to setup  Large area covered Contras  High power consumption of WLAN card  Poor update rate  Calibration step

Ultra Wide Band Features  No multipath distortion  Time Difference of Arrival, Angle of Arrival  Accuracy: 15cm Pros  Accuracy  Good update rate Contras  Special hardware  Complex Setup

Our hybrid solution WLAN from Ekahau Inc  Coverage: whole floor  Accuracy: 3 meters UWB from Ubisense  Coverage: single room  Accuracy: 20 cm IR from guideID and Eyeled  Coverage: few emitters in front of pictures

Pathfinding  Introduction  Contents  Indoor positioning systems  Pathfinding + map creation  Map viewer + navigation  Demo  conclusion

SVG Map generation Problem: the same SVG map will not render on all platforms Solution: create a common semantic description of the map together with transformation rules specific to each platform Implementation  DTD suitable for room plans  User Interface to define a new map  XSLT transformation to output SVG  A XSLT file for each target platform

The A* algorithm implementation A* algorithm  Is a graph search algorithm that finds a shortest path from a given initial node to a given goal node  Uses an heuristic to direct the search  Cost function is the distance between two nodes Implementation  Route computation on client (Windows Mobile 2003)  Implemented using STL library  Graph stored as text file

Map viewer  Introduction  Contents  Indoor positioning systems  Pathfinding + helper tools  Map viewer + navigation  Demo  conclusion

Viewer functionalities  Zoom in/out, panning  Display of the current position  Selection of a destination and display of the optimal route  Animations of objects  Support for information browsing on the map

On the search for perfection First step: Personal Java application rendering raster bitmap Drawbacks:  Raster bitmap: not scalable, high footprint  Java: weak user interface, waste of system resources, no access to hardware resources Next step: Native C++ application rendering SVG. Which SVG viewer to use ?

Which SVG viewer? Only two native SVG viewers available for Windows Mobile-based PDAs: eSVG and BitFlash eSVG  eSVG 1.6 license purchased in Mai 2003  Performance issues  Latest version with.NET support BitFlash  BitFlash SDK license purchased in Spring 2004  Fast rendering and good interaction capabilities

Using BitFlash SDK Usage guidelines  Create player instance, load document  Communication with the player via commands and callback functions, DOM API  Only one thread should access the player at the same time Example  Zooming in: BFZoomEvent zoomData; zoomData.fpFactor = 0x7FFF;//0xcccc; // 1.5 in fixed point zoomData.iCenterX = (BF_INT16)point.x; zoomData.iCenterY = (BF_INT16)point.y; int dwWait=WaitForSingleObject(hSVGPlayerSemaphore,INFINITE); CheckStatus(BFprocessCommand( pPlayer, BF_COMMAND_VIEW_ZOOM, &zoomData )); CheckStatus(BFprocessCommand( pPlayer, BF_COMMAND_VIEW_REDRAW, 0 )); ReleaseSemaphore(hSVGPlayerSemaphore,1,NULL);

Integration of positioning technologies Ekahau/Ubisense  Server: Middleware server connecting to Ekahau and Ubisense Server, keeping position information up-to- date and delivering position data to clients  Client: Location Thread connects to server, parses messages and refreshes buddy position on map IR  IR thread is listening on IR port (serial)  IR code found => trigger animation Issues  Refresh rate (only Orinoco cards provide good results)  Integration

Demo

Conclusion Positioning  Appropriate combination of positioning systems needed to achieve best tradeoff between quality of service and cost  Indoor navigation is still a very challenging research topic SVG  SVG maps are perfect for mobile navigation  Rendering of SVG maps no longer too slow Future work  Better navigation : audio output and personalized routes  Seemless integration of positioning systems  Tests on Symbian and.NET

Thank you !