1. Faculty of Engineering, dept. ELEC Positioning a mobile terminal Combining GPS and GSM techniques Nico Deblauwe Nico.Deblauwe@vub.ac.be

2. 2 Nico Deblauwe FITCE Conference Warsaw 07 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 GSM-based positioning is feasible  Combining it with other technologies  Application in niche markets Public Transport Case Study

3. 3 Nico Deblauwe FITCE Conference Warsaw 07 Location-based Services (LBS) LBS provide information that is created or filtered taking the current location of a mobile object (user or target) into consideration Emergency services Emergency services Mobile marketing Mobile marketing Mobile gaming Mobile gaming Navigation services Navigation services Child tracking Child tracking Traffic telematics Traffic telematics Finding stolen cars Finding stolen cars Community services Community services Finder services Finder services Alert services Alert services Tourist guide Tourist guide Pet tracking Pet tracking Health care Health care Toll collecting Toll collecting Safety services Safety services Goods tracking Goods tracking Supplem. services Supplem. services

4. 4 Nico Deblauwe FITCE Conference Warsaw 07 Classification of LBS [1/4] 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 Operation mode

5. 5 Nico Deblauwe FITCE Conference Warsaw 07 Classification of LBS [2/4] 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 Referencing

6. 6 Nico Deblauwe FITCE Conference Warsaw 07 Classification of LBS [3/4] 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 Organization of communication

7. 7 Nico Deblauwe FITCE Conference Warsaw 07 Classification of LBS [4/4] 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 How position is used

8. 8 Nico Deblauwe FITCE Conference Warsaw 07 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. 9 Nico Deblauwe FITCE Conference Warsaw 07 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. 10 Nico Deblauwe FITCE Conference Warsaw 07 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. 11 Nico Deblauwe FITCE Conference Warsaw 07 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. 12 Nico Deblauwe FITCE Conference Warsaw 07 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  

13. 13 Nico Deblauwe FITCE Conference Warsaw 07 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. 14 Nico Deblauwe FITCE Conference Warsaw 07 Using Multiple Positioning Technologies Which combinations? GPS-aided Proximity sensing Additional hardware Using Signal Strengths (RSS) Observation No need for constant spatio- temporal resolution 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 Combine technologies dynamically, two examples 1 2

15. 15 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID GPS

16. 16 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS 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. 17 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID 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 Cell-ID GPS

18. 18 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Use for proactive applications Two terminals on the move Objects centrally tracked Both GPS & Cell-ID available No GPS when Cell-ID is ok Cell-ID GPS

19. 19 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Use for proactive applications Two terminals on the move Objects centrally tracked Both GPS & Cell-ID available No GPS when Cell-ID is ok Cell-ID GPS

20. 20 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Use for reactive applications Terminal looking for PoI > Satisfying resolution > Unsatisfying resolution Cell-ID GPS

21. 21 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Use for reactive applications Terminal looking for PoI > Satisfying resolution > Unsatisfying resolution Use Cell-ID Cell-ID GPS

22. 22 Nico Deblauwe FITCE Conference Warsaw 07 Combining GPS and GSM Cell-ID Two philosophies possible: supporting technology base technology GPS Cell-ID Use for reactive applications Terminal looking for PoI > Satisfying resolution > Unsatisfying resolution Switch to GPS Cell-ID GPS

23. 23 Nico Deblauwe FITCE Conference Warsaw 07 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?