1. CS H ONORS U NDERGRADUATE R ESEARCH P ROGRAM - F INAL P ROJECT T ALK Tingyu Thomas Lin Advisor: Professor Deborah Estrin Date of Presentation: Thursday, June 7, 2007

2. A N I NVESTIGATION OF A COUSTIC S OURCE L OCALIZATION IN A H ETEROGENEOUS N ETWORK

3. O UTLINE Overview of system Design Simulation Experimentation and Results

4. O UTLINE Overview of system Design Simulation Experimentation and Results

5. O VERVIEW OF S YSTEM Two tiered distributed sensing network: ENSBox + Lots of resources, precise - Expensive in cost, resources, to deploy in large numbers Mica2 Mote + Cheap to deploy in large numbers - Resource constraints, poor resolution in measurements Why? To leverage the advantages respective advantages General context of acoustic source localization

6. O UTLINE Overview of system Design Simulation Experimentation and Results

7. S YSTEM G OALS Functionality to support acoustic localization: Wireless Communication Time synchronization Self-calibration ENSBox Already have functionality Mica2 Mote Extend functionality to motes

8. W IRELESS C OMMUNICATION & T IME S YNC Mote-Mote communication Mica2 motes - onboard 433 MHz radio BMAC Transport/Routing Protocols Mote-ENSBox communication ENSBox – tethered mote Time Synchronization Flooding Time Synchronization Protocol (FTSP) Time translation between ENSBox & Motes

9. S ELF -C ALIBRATION How to determine positions of motes w/o any prior knowledge of location? ENSBox acoustic source localization facilities Equip motes with speakers Process: Schedule the motes to emit a signal ENSBoxes localize signal Localization results => mote locations

10. DOA-B ASED L OCALIZATION Determine Direction of Arrival (DOA) Combine DOAs

11. DOA L IKELIHOOD P LOTS

12. F USING DOA S : P SEUDO - LIKELIHOOD M APS

13. LOCALIZATION, CONT’D The Mica2 Motes now support: Wireless Communication Time synchronization Self-calibration

14. O UTLINE Overview of system Design Simulation Experimentation and Results

15. G OALS OF S IMULATION Modeling System Rapid Simulation Controllable Self-Calibration Accuracy of localizing Motes w/ ENSBoxes

16. S IMULATING L OCALIZATION Field 60x60 m, no obstructions ENSBox placement and self-calibration Errors in self-calibration Gaussian errors: 4 cm for position,.96 degrees in orientation Mote Localization Sound wave DOA and pseudo-likelihood maps

17. S IMULATING L OCALIZATION

18. O UTLINE Overview of system Design Simulation Experimentation and Results

19. E XPERIMENT #1 Questions: Frequency of call? More ENSBoxes = better? Scenario: 20 motes randomly but uniformly generated in field Initially: 5 ENSBoxes Localize motes using different frequency calls 1 KHz, 4 KHz, 10 KHz Increase ENSBox count up to 8

20. EXPERIMENT #1, CONT’D Squares = ENSBoxes Blue = Motes Red = Estimated mote positions Call: 1 KHz

21. E XPERIMENT #1 R ESULTS Table of mean errors ± standard deviation, units in cm In this particular simulation setting: Frequency of call, no effect Increasing ENSBox count, no effect Frequency of Call 1 KHz4 KHz10 KHz 5 47±23 47±24 Number of6 38±23 39±22 ENSBoxes7 40±3539±3536±31 839±2540±2538±23

22. E XPERIMENT #1 E XTENSION For 1 KHz call localization results for 9 and 10 ENSBoxes Indicates > 5 ENSBoxes != >accuracy Frequency of Call 1 KHz4 KHz10 KHz 5 47±23 47±24 Number of6 38±23 39±22 ENSBoxes7 40±3539±3536±31 8 39±2540±2538±23 9 44±19 -- 1035±30--

23. E XPERIMENT #2 Question: Least amount of ENSBoxes w/o losing accuracy? Scenario: Same 20 motes 5 ENSBoxes to start from, 1 KHz calls from motes ENSBoxes removed, motes localized with remaining boxes

24. EXPERIMENT #2, CONT’D Same 5 ENSBoxes, 20 motes.

25. E XPERIMENT #2 R ESULTS 1 ENSBox Removed, 4 leftError in Measurement IDMeanStd. dev 14618 23215 35224 45024 55132 2 ENSBox Removed, 3 leftError in Measurement IDsMeanStd. dev 1,25233 1,37771 1,46022 1,58673 2,34019 2,44640 2,53321 3,46842 3,56332 4,56233 3 ENSBox Removed, 2 leftError in Measurement IDsMeanStd. dev 1,2,3138114 1,2,48784 1,2,57350 1,3,4148157 1,3,5160152 1,4,5133170 2,3,4106257 2,3,54021 2,4,588104 3,4,5173242

26. EXPERIMENT #2 RESULTS, CONT’D In simulation framework: < 5 ENSBoxes = < accuracy Suggests: At least 5 ENSBoxes in the 60x60 m yields most accuracy w/ errors about 40±25 cm Comparable to other mote acoustic localization schemes