1. Localization algorithms for wireless sensor networks M.Srbinovska, C.Gavrovski Ss.Cyril and Methodius University, Skopje Faculty of Electrical Engineering and IT- Skopje, R. Macedonia

2. NIS, 2010 2 19/05/2014 OUTLINE Introduction Propagation models Measurement uncertainty for position estimation Experimental results Conclusion Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

3. NIS, 2010 3 19/05/2014 Introduction Wireless sensor networks monitor large areas, monitoring the environment, air, water and soil. GPS (global positioning system) does not work indoors. Define the coordinates during the instalation. Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

4. NIS, 2010 4 19/05/2014 Wireless channel model Three propagation models are used: Free space propagation model Two – Ray ground model Log-distance model Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

5. NIS, 2010 5 19/05/2014 Received Signal Strength Indicator (RSSI) RSSI – power of the signal at the receiver Direct path n- path loss exponent Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

6. NIS, 2010 6 19/05/2014 Received Signal Strength Indicator (RSSI) The RSSI can be used to characterize the channel status. Friis free space transmission equation is: Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

7. NIS, 2010 7 19/05/2014 Multilateration Minimizing the mean square error: Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

8. NIS, 2010 8 19/05/2014 Measured vs. calculated RSSI with different n Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

9. NIS, 2010 9 19/05/2014 Root mean square error between theoretical and measured RSSI with different n Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

10. NIS, 2010 10 19/05/2014 Received Signal Strength Indicator Sensor node It works at the 2.4 GHz ISM Band. Each board features : Silicon laboratories C8051F121 microcontroller Chipcon CC2420 2.4 GHz 802.15.4 transceiver. Position of sensor nodes X3X3 X1X1 X2X2 A4A4 A5A5 A6A6 Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

11. NIS, 2010 11 19/05/2014 Measurement uncertainty for position estimation Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

12. NIS, 2010 12 19/05/2014 Experimental results Distance uncertainties of the sensor nodes Projekt ISSNBS DAAD Deutscher Akademischer Austausch Dienst German Academic Exchange Service

13. NIS, 2010 13 19/05/2014 Conclusion The relationship between RSSI and distance was determined through practical experiments. Distance uncertainties of the sensor nodes through experimental measurements were presented. Wireless sensor networks are widely applicable to many practical applications including environmental monitoring, military applications etc. in which sensors may need to know their geographical locations

14. NIS, 2010 14 19/05/2014 Thank You for your attention!