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Title:LOKALIZACIJSKE TEHNIKE V BREZŽIČNIH SENZORSKIH OMREŽJIH
Authors:Malajner, Marko (Author)
Čučej, Žarko (Mentor) More about this mentor... New window
Planinšič, Peter (Co-mentor)
Files:.pdf MAG_Malajner_Marko_2009.pdf (2,90 MB)
MD5: 3AC39E12705BF1D4A28514A48A1C6ED0
 
Language:Slovenian
Work type:Master's thesis (m2)
Organization:FERI - Faculty of Electrical Engineering and Computer Science
Abstract:V magistrskem delu se ukvarjamo z brezžičnimi senzorskimi omrežji (v nadaljevanju BSO). Brezžična senzorska omrežja se uporabljajo za nadzorovanje in kontrolo okolice. Vsaka senzorska enota sestoji iz senzorskega dela, ki zaznava okolico in iz radijskega dela, ki te podatke distribuira bazni postaji (v eni ali več etapah). Vsak podatek o lokalnem fenomenu nima vrednosti, če ne vemo od kje prihaja. Zato smo se v tem magistrskem delu posvetili lokalizaciji (ali pozicioniranju) senzorskih enot. Najenostavnejšo in ob enem dovolj natančno lokalizacijo v odprtem prostoru lahko dosežemo z GPS navigacijo. Ob predpostavki, da senzorsko omrežje sestoji iz nekaj deset do nekaj tisoč senzorskih enot bi integracija GPS bila cenovno neprimerna. Pa tudi iz vidika porabe energije ni primerno, ker se enote napajajo iz omejenega vira energije. Zato se v senzorskih omrežjih poslužujemo drugih cenejših metod, ki jih bomo podrobneje opisali v nalogi. V osnovi pa so razdeljene glede na merjenje dveh fizikalnih količin: čas in moč signala. Pri metodah, kjer merimo čas, merimo čas potovanja signala od točke A do točke B (TOA - time of arrival). Merjenje časa potovanja signala se poslužuje zelo razširjen GPS. Druga metoda je merjenje moči signala. Za vsako senzorsko enoto poznamo oddajno moč, če je sprejemna enota zmožna meriti moč signala, lahko ocenimo približno razdaljo med sprejemnikom in oddajnikom. Boljši model širjenja radijskih valov poznamo, natančneje lahko ocenimo razdaljo. V magistrski nalogi bomo določevali lokalizacijo s pomočjo zakonov širjenja radijskih valov. Za ta način smo se odločili, ker imajo vsi prenosni radijski moduli (IEEE802.11) vgrajen mehanizem za merjenje moči sprejetega signala (RSSI). V naših raziskavah smo uporabili dva radijska modula: MRF24J40 z implementiranim fizičnim slojem ZigBee protokola in CC2500, ki ni fizično vezan na katerikoli protokol. Oba radia delujeta na ISM 2.4 GHz frekvenčnem pasu.V delu bomo prikazali razvoj naše senzorske enote SPaRCMosquito, programsko opremo za modeliranje in lokalizacijo senzorskih omrežij SPaRCSoft. Podali bomo rezultate in analize meritev prenosnega kanala in ocenitev položajev senzorskih enot s pomočjo meritev parametrov prenosnega kanala in algoritmov za lokalizacijo.
Keywords:brezžična senzorska omrežja, model širjenja radijskih valov, meritev razdalje, lokalizacija
Year of publishing:2009
Publisher:[M. Malajner]
Source:Maribor
UDC:621.396.74:681.586
COBISS_ID:13551894 New window
NUK URN:URN:SI:UM:DK:60YLDTPC
Views:2611
Downloads:206
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:KTFMB - FERI
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Secondary language

Language:English
Title:LOCALIZATION TECHNIQUES IN WIRELESS SENSOR NETWORKS
Abstract:Wireless sensor networks (WSNs) have become a very interesting research topic in the last few years. Recent advantages in micro-electro-mechanical systems technology, wireless communications, and digital electronics have enabled the development of low-cost sensor nodes that are capable to communicate to each other in short distances. These small nodes consist of a few components: radio part for spreading data, sensor part for sensing environment phenomena, processing unit and power supply. There are many active applications where WSN can be used: from military applications to healthcare and environment monitoring. Usually all data from sensor field are collected at a base station and this data is meaningless without the position information. There are many techniques for determining distance between nodes. Physically, we can measure the time of signal (acoustic or RF) arrival, angle of signal arrival or received power of signal. Very popular GPS locating system uses time of signal arrival between satellite and device. On the other hand we can measure signal's received power. 802.11 radio modules support Received Signal Strength Indicator (RSSI), which means, we can calculate received power for each received packet. The power or energy of a signal traveling between two nodes is a signal parameter that contains information related to the distance between those nodes. This parameter can be used together with path-loss and shadowing model for distance estimation. In this work we will describe our implementation of the RSSI technique, accompanying problems, accuracy, etc. We used nodes which consist: ZigBee MRF24J40 radio daughterboard or CC2500 radio, and SPaRCMosquito motherboard based on ARM microcontroller. Results and analysis of measurements and localization estimation will be shown in this work.
Keywords:wireless sensor network, radio propagation model, distance measurement, localization


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