Localization with RSSI Method at Wireless Sensor Networks

1
Localization with RSSI Method at Wireless Sensor
Networks

• Osman Ceylan
• Electronics Engineering
• PhD Student, Istanbul Technical University,
  Turkiye

28.10.2009
2
Presantation Plan

• Networks
• Computer Networks
• Wireless Sensor Networks
• Hardware specifications
• Advantages
• Localization Problem
• Localization techniques
• RSSI Method

3
Networks

• Computer Networks

4
Networks

• Wireless Sensor Networks

5
Wireless Sensor Networks

• Wireless sensor networks and computer networks
  are similar.
• Able to send/receive data
• Internal control unit
• But there are some significant differences.
• Very small hardware
• Wireless communication

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Hardware Specifications

• Hardwares are low power small devices.
• Working with battery for 6-24 months
• Easy installing and carring
• Communicaton is wireless.
• Generally uses ISM bands ( Especially 433 MHz and
  2.4 GHz)
• Low communication range (up to 200 meters at
  outdoor)
• Microcontroller is processing unit.
• Analog and Digital I/O
• Internal RAM, Flash

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Advantages of WSNs Versus Wireless Computer
Networks

• Wireless sensor networks can be designed and
  implemented much more bigger than computer
  networks easily and cheaply.
• Network organization can be setted up
  automatically by the hardwares.
• Hardwares
• Very low power consumption
• Very low failure rates

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Localization Problem

• How can we find an objects exact position?
• Triangulation

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Localization Techniques

• GPS
• Only outdoor
• 1-15 meters error
• GSM
• Bad in cities
• 100 meters error
• Sensor Networs
• Ultrasonic Based Systems
• Very High Accuricy (under 5 cm), but very low
  range (max 10 meters)
• Hard setting up
• Not user friendly
• RSSI Based Systems
• 1 meter error

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RSSI Method

• Received Signal Strength Indication is a
  measurement of the received signals power.
• Radio frequency signals power decreases with the
  distance
• Loss (dB) 20log(d)20log(f)32.45
• dkm, fMHz
• We know communication frequency and transmit
  power.So if we can measure received signals
  powers We can find the distance d.
• Received Power Transmited power Path Loss

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RSSI Method
Fixed Node x3,y3
Fixed Node x4,y4
R4
R3
Moving Node
R2
R1
Fixed Node x2,y2
Fixed Node x1,y1
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Advantages of RSSI Method at Localization

• No directional sensor like ultrasonic systems
• Indoor and outdoor usage
• Data communication and sensor usage at same
  hardware

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Difficulties at RSSI Method

• Distance calculation is related RF signal power
  at receiver.
• Multipath propagation
• Fading effects
• Bad frontend devices

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Industrial Usage

• Data collection
• Sensor datas collecting
• Temperature maps producing
• Tracking and location
• Object tracking at production lines
• Person tracking at hospitals, penitentiaries
• Animal tracking at farms

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Defence Systems

• Ammunition Tracking in a war or storage
• Soldier Tracking in a war or trainging
• Detecting ally or enemy
• Data collection
• For a person dead/alive
• For a object existing/operating/moving

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Team

• Electronics Circuits and Antennas Design Team
• 1PHd, 4 BSc
• Embedded Design Team
• 2 Msc, 6 BSc
• Command-Control Software Design Team
• 1 MSc, 4 BSc

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Thanks