Positioning a mobile terminal Combining GPS and GSM techniques

1. Positioning a mobile terminalCombining GPS and GSM techniques Nico Deblauwe Nico.Deblauwe@vub.ac.be

2. GSM-based positioning is feasible Combining it with other technologiesApplication in niche markets Public Transport Case Study Presentation outline 1) Location-based Services • Some basics • Characterization 2) Technology study • Locating a mobile device • Combining technologies • GPS & GSM Cell-ID • Combining GSM Cell-ID and RSS

3. Navigation services Child tracking Mobile gaming Traffic telematics Mobile marketing Finding stolen cars Finder services Emergency services Supplem. services Health care Goods tracking Pet tracking Alert services Community services Safety services Tourist guide Toll collecting Location-based Services (LBS) LBS provide informationthat is created or filtered taking the currentlocationof a mobile object (user or target)into consideration

4. Reactive (pull) Needs explicit request of user Typical for “old fashioned” LBSs Proactive (push) User subscribes for spatial or timed events Quality of Service demands possible Classification of LBS [1/4] Operationmode

5. Self-referencing User and tracked object are the same Good match with terminal-based positioning Cross-referencing User and tracked object are different Optimization of communication needed Classification of LBS [2/4] Referencing

6. Centrally managed Efficient position/communication management Privacy issues – trust relationship Peer-to-peer operation User has more control on his position data Privacy issues – what info to broadcast/keep Classification of LBS [3/4] Organization of communication

7. Location-of-target Target mapped to a location Events derived from location+target Targets-at-location (zone-service) Area is watched for visitors Ideal for mobile marketing Classification of LBS [4/4] How position is used

8. Public Transport LBS Segments [1/2] User Application Segment • Informing • “Where is the most nearby bus stop?” • Routing • “How to get from HERE to Location X?” • Navigation • “You have two minutes to get to the bus stop” • “At the next bus stop, get off and …” Characterization

9. Public Transport LBS segments [2/2] Fleet Management segment • Management tool • Decision aid (short term) • Optimize routes (long term) • Data provider • Source for geospatial data for User Application Characterization

10. Mobile Location Estimation [1/4] How to determine the position of a device? • Satellite-aided E.g. GPS, NA-GPS • High precision • Battery usage • Canyoning • Proximity sensing • Additional hardware • Using Signal Strengths 

11. Mobile Location Estimation [2/4] How to determine the position of a device? • GPS-aided • Proximity sensing E.g. Cell-ID • Superb coverage • Low battery load • Varying & low accuracy • Additional hardware • Using Signal Strengths 

12. Mobile Location Estimation [3/4] How to determine the position of a device? • GPS-aided • Proximity sensing • Additional hardware E.g. E-OTD, TDOA, … • Satisfactory precision • Deployment costs • Needs new phones • Using Signal Strengths LMU  LMU LMU

13. Mobile Location Estimation [4/4] How to determine the position of a device? • GPS-aided • Proximity sensing • Additional hardware • Using Signal Strengths • Possible from the phone • No network changes  Medium precision • Rather difficult to treat 

14. Observation • No need for constant spatio- temporal resolution Combine technologies dynamically, two examples 2 1 • RSS and Cell-ID • Cell-ID:first estimate, cache • RSS:positioning • => refer to paper for details • GPS and Cell-ID • Cell-ID:low energy use • GPS:high accuracy • => let’s look at some details Using Multiple Positioning Technologies Which combinations? • GPS-aided • Proximity sensing • Additional hardware • Using Signal Strengths (RSS)

15. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology Cell-ID GPS Cell-ID GPS

16. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for proactive applications Two terminals on the move Objects centrally tracked Both GPS & Cell-ID available No GPS when Cell-ID is ok bus stop

17. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for proactive applications Proximity distance Two terminals on the move Objects centrally tracked Both GPS & Cell-ID available No GPS when Cell-ID is ok

18. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for proactive applications Two terminals on the move Objects centrally tracked Both GPS & Cell-ID available No GPS when Cell-ID is ok

19. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for proactive applications Two terminals on the move Objects centrally tracked Both GPS & Cell-ID available No GPS when Cell-ID is ok

20. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for reactive applications Terminal looking for PoI > Satisfying resolution > Unsatisfying resolution

21. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for reactive applications Use Cell-ID Terminal looking for PoI > Satisfying resolution > Unsatisfying resolution

22. Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Cell-ID GPS Use for reactive applications Switch to GPS Terminal looking for PoI > Satisfying resolution > Unsatisfying resolution

23. What to remember? Situation • Performant, multi-technology, devices ! Weaknesses: non-standardized, limited battery • Ready for LBS 2.0 Role GSM-based positioning • Becoming mature, apply • in niche markets: e.g. bus tracker box • in combination with other technologies: e.g. GPS • Techniques also valid for UMTS, … Any further questions?