Localization in Wireless Sensor Networks
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Transcript Localization in Wireless Sensor Networks
Poorya Ghafoorpoor Yazdi
Mohammad Zerrat Talab
Masoud Toughian
Maziar Movahedi
105003
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Definition about sensor node
Comparison of WSN with Ad Hoc Network
General Application of the wireless sensor networks
Manufacturing Application of WSN
Definition about Localization of WSN
Specific application of localization in manufacturing
Definition about wireless sensors
Wireless Sensor Networks
Application of WSN
Application of WSN in Manufacturing
Localization – What? Why?
Classification of Localization Algorithms
Examples of Localization Techniques
Node Hardware
1Kbps - 1Mbps,
3-100 Meters,
Lossy Transmissions
128KB-1MB
Limited Storage
Transceiver
Memory
Embedded
Processor
8-bit, 10 MHz
Slow Computations
Sensors
66% of Total Cost
Requires Supervision
Battery
Limited Lifetime
Energy Harvesting System
Wireless Sensor Networks are networks that consists of
sensors which are distributed in an ad hoc manner.
These sensors work with each other to sense some physical
phenomenon and then the information gathered is processed to
get relevant results.
Wireless sensor networks consists of protocols and algorithms
with self-organizing capabilities.
◦ Wireless sensor networks mainly use broadcast
communication while ad hoc networks use point-to-point
communication.
◦ Unlike ad hoc networks wireless sensor networks are limited
by sensors limited power, energy and computational capability.
◦ Sensor nodes may not have global ID because of the large
amount of overhead and large number of sensors.
Military applications:
Monitoring friendly forces,
equipment and ammunition
Exploration of opposing forces and
terrain
Battlefield surveillance
Battle damage assessment
Nuclear, biological and chemical
attack detection
Health applications:
Tele-monitoring of human
physiological data
Tracking and monitoring patients
and doctors inside a hospital
Drug administration in hospitals
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Example of Products Applicable for
Health care
Pulse Oximeter
Glucose Meter
Electrocardiogram (ECG)
Social Alarm Devices
Smart Buildings
Sensors and sensor networks are used in multiple smart
building applications:
Heating, ventilation, and air conditioning systems
Lightning
Air quality and window control
Systems switching off devices
Standard household applications (e.g. televisions,
washing machines)
Security and safety (access control)
Example of Smart buildings
The headquarters of the New
York Times is an example of
how different smart building
technologies can be combined
to reduce energy consumption
and to increase user comfort.
Overall, the building consumes
30 % less energy than
traditional office skyscrapers.
Environmental Monitoring
This sensor measures light,
temperature, and humidity, and
can be equipped to do soilmoisture measurements.
The system takes measurements
every second and transmits over
40 meters.(about 3cm diameter)
It was developed for planetary
monitoring by the Jet Propulsion
Laboratory.
Some Interesting Applications
MIT d'Arbeloff Lab – The ring sensor
Monitors the physiological status of the
wearer and transmits the information to the
medical professional over the Internet
Oak Ridge National Laboratory
Nose-on-a-chip is a MEMS-based sensor
It can detect 400 species of gases and
transmit a signal indicating the level to a
central control station
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Investigate behavior of children/patient
Features:
◦
◦
◦
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Speech recording / replaying
Position detection
Direction detection / estimation(compass)
Weather data: Temperature, Humidity, Pressure, Light
WSNs can be used advantageously for rare event detection or
periodic data collection for manufacturing applications. In rare
event detection, sensors are used to detect and classify rare
and random events, such as alarm and fault detection
notifications due to important changes in machine, process,
plant security or operator actions. On the other hand, periodic
data collection is required for operations such as tracking of
the material flows, health monitoring of equipment/process.
Such monitoring and control applications reduce the labor cost
and human errors.
Likes
Mobility
Compactness
Flexibility
Low cost
Capability to monitor rotating
equipment
Short range (security)
Ease of installation
High reliability
Impetus to enhance electronics
support
Dislikes
Change to status quo
Complexity
High cost for coverage in large plants
Security issues
Portability issues (power)
Unproven reliability
Too risky for process control
Lack of experience in troubleshooting
(staff)
Restricted infrastructure flexibility
once implemented
Lack of analysis tools
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Inventory Tracking
In-Process Parts Tracking
Customer Tracking
Plant Equipment Maintenance and Monitoring
What?
◦ To determine the physical coordinates of a group of sensor nodes in a
wireless sensor network (WSN)
◦ Due to application context, use of GPS is unrealistic, therefore, sensors
need to self-organize a coordinate system
Why?
◦ To report data that is geographically meaningful
◦ Services such as routing rely on location information; geographic
routing protocols; context-based routing protocols, location-aware
services
In general, almost all the sensor network localization
algorithms share three main phases
DISTANCE ESTIMATION
POSITION COMPUTATION
LOCALIZATION ALGHORITHM
Start
Exist an Unknown Node which has at
least three reference node in its
coverage area
End
Select an Unknown Node
Unknown Nod Selection
Obtain a Vague Position
Select Reference Node
Drive local Position for
reference Node
Distance Estimation
Estimate the Distance to the
Reference Node
Any Selected Reference Node
Without Estimated Distance
Calculate the Position of the
Selected Unknown Node
Position Computation
The distance estimation phase involves measurement techniques to
estimate the relative distance between the nodes.
The Position computation consists of algorithms to calculate the
coordinates of the unknown node with respect to the known anchor
nodes or other neighboring nodes.
The localization algorithm, in general, determines how the
information concerning distances and positions, is manipulated in
order to allow most or all of the nodes of a WSN to estimate their
position. Optimally the localization algorithm may involve
algorithms to reduce the errors and refine the node positions.
There are four common methods for measuring in distance
estimation technique:
ANGLE OF ARRIVAL (AOA)
TIME OF ARRIVAL (TOA)
TIME DIFFERENT OF ARRIVAL (TDOA)
THE RECEIVED SIGNAL STRENGH INDICATOR (RSSI)
ANGLE OF ARRIVAL method allows each sensor to
evaluate the relative angles between received radio signals
TIME OF ARRIVAL method tries to estimate distances
between two nodes using time based measures
TIME DIFFERENT OF ARRIVAL is a method for
determining the distance between a mobile station and
nearby synchronized base station
THE RECEIVED SIGNAL STRENGTH INDICATOR
techniques are used to translate signal strength into
distance.
The common methods for position computation techniques
are:
LATERATION
ANGULATION
LATERATION techniques based on the precise
measurements to three non collinear anchors. Lateration
with more than three anchors called multilateration.
ANGULATION or triangulation is based on information
about angles instead of distance.
According to the ways of Sensors implementation, we classify the current
wireless sensor network localization algorithms into several categories
such as:
Centralized vs Distributed
Anchor-free vs Anchor-based
Range-free vs Range-based
Mobile vs Stationary
Range Based Centralized Localization using
Neural Networks
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(1,1)
(4,3)
(2,7)
(5,5)
(7.5,7.3)
(9,5)
Anchor
node 1
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Anchor
Node 2
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Anchor
Node 3
-74
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Anchor
Node 4
-75
-73
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