College of Engineering

Anchor Nodes Placement for Effective

Passive Localization

Anchor Nodes Placement for Effective

Passive Localization

Karthikeyan Pasupathy

Major Advisor: Dr. Robert Akl

Department of Computer Science and Engineering

Karthikeyan Pasupathy

Major Advisor: Dr. Robert Akl

Department of Computer Science and Engineering

OutlineOutline

• Objective

• Overview of Sensor Networks

• Localization

• Motivation

• Anchor Node Placement

• Simulations and Results

• Conclusions and Future Directions

• Objective

• Overview of Sensor Networks

• Localization

• Motivation

• Anchor Node Placement

• Simulations and Results

• Conclusions and Future Directions04/20/23 2/46

ObjectiveObjective

• How to place anchor nodes for better passive localization ?

• How to place anchor nodes for better passive localization ?

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Overview of Sensor NetworksOverview of Sensor Networks

• Made of tiny sensor nodes networked together

• Communicate wirelessly

• Made of tiny sensor nodes networked together

• Communicate wirelessly

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Overview of Sensor NetworksOverview of Sensor Networks

• Architecture• Architecture

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Overview of Sensor NetworksOverview of Sensor Networks

• Limitations

• Deployment

• Short lifetime

• Unmanned

• Limitations

• Deployment

• Short lifetime

• Unmanned

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Overview of Sensor NetworksOverview of Sensor Networks

Applications

• Military

• Reconnaissance, surveillance, shooter’s location, target tracking etc.

• Environment

• Track animals, birds, environmental conditions; detect forest fires, floods

Applications

• Military

• Reconnaissance, surveillance, shooter’s location, target tracking etc.

• Environment

• Track animals, birds, environmental conditions; detect forest fires, floods

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Overview of Sensor NetworksOverview of Sensor Networks

Applications

• Healthcare

• Monitor doctors, patients, drug administrators

• Hospitals – monitor physiological signals

• Medication – avoid wrong medication

Applications

• Healthcare

• Monitor doctors, patients, drug administrators

• Hospitals – monitor physiological signals

• Medication – avoid wrong medication

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Overview of Sensor NetworksOverview of Sensor Networks

Applications

• Domestic

• Smart home

• Smart kindergarten

• Industry

• Machine diagnosis; monitor radiation, material fatigue, product quality

Applications

• Domestic

• Smart home

• Smart kindergarten

• Industry

• Machine diagnosis; monitor radiation, material fatigue, product quality

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LocalizationLocalization

• Where are these nodes ?

• Local position

• Global position

• How to localize?

• GPS

• Where are these nodes ?

• Local position

• Global position

• How to localize?

• GPS

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LocalizationLocalization

• Localization Systems

• Centralized

• Distributed

• Localization Systems

• Centralized

• Distributed

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LocalizationLocalization

• Centralized

• Not limited by algorithm

• More accurate results

• Traffic congestion

• Computational complexity

• Centralized

• Not limited by algorithm

• More accurate results

• Traffic congestion

• Computational complexity

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LocalizationLocalization

• Distributed

• Usually iterative

• Algorithms generally energy efficient and self organizing

• Less accurate

• Distributed

• Usually iterative

• Algorithms generally energy efficient and self organizing

• Less accurate

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LocalizationLocalization

• Different techniques

• Received Signal Strength (RSS)

• Time of Arrival (TOA)

• Angle of Arrival (AOA)

• Different techniques

• Received Signal Strength (RSS)

• Time of Arrival (TOA)

• Angle of Arrival (AOA)

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RSSRSS

• Signal strength

• Inverse Square law

• Error of several meters

• Less accurate

• Vulnerable to occlusions

• Signal strength

• Inverse Square law

• Error of several meters

• Less accurate

• Vulnerable to occlusions

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Radio Hop CountRadio Hop Count

• Nodes separated by at most R

• Affected by hindrances

• Nodes separated by at most R

• Affected by hindrances

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TOATOA

• Difference in propagation speed of signals

• Difference in propagation speed of signals

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TOATOA

• More accurate

• Vulnerable to occlusions

• More accurate

• Vulnerable to occlusions

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Angle of ArrivalAngle of Arrival

• Phase / Time difference recorded by an array of microphones

• Expensive

• Bulkier

• Not practical to implement

• Sensor size shrinks

• Phase / Time difference recorded by an array of microphones

• Expensive

• Bulkier

• Not practical to implement

• Sensor size shrinks

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Passive LocalizationPassive Localization

• Why passive ?

• Nodes are silent

• Advantages

• No external source for signals

• Can work with existing data

• Can be used in most outdoor applications

• Why passive ?

• Nodes are silent

• Advantages

• No external source for signals

• Can work with existing data

• Can be used in most outdoor applications

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Passive LocalizationPassive Localization

• Disadvantages

• Centralized

• Not suitable for indoor applications

• Disadvantages

• Centralized

• Not suitable for indoor applications

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Passive LocalizationPassive Localization

• Event detection

• Projected distances

• Localization

• Distance Matrix

• SVD

• Event detection

• Projected distances

• Localization

• Distance Matrix

• SVD

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Passive LocalizationPassive Localization

• Localization

• Linear Combination coefficients

• Localization

• Linear Combination coefficients

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MotivationMotivation

• Deployment of anchor nodes at specific position not easy

• Function of anchor nodes are different in passive localization

• Deployment of anchor nodes at specific position not easy

• Function of anchor nodes are different in passive localization

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Anchor Node PlacementAnchor Node Placement

• Density

• Better to have more anchor nodes

• Deployment and hardware costs

• Redundancy

• Geometry

• No three anchor nodes may be linearly related

• Density

• Better to have more anchor nodes

• Deployment and hardware costs

• Redundancy

• Geometry

• No three anchor nodes may be linearly related

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Simulations and resultsSimulations and results

Assumptions:

• Propagation velocity – unity

• Clocks - time synchronized.

• Global events - distributed around the network.

• Signal processing – skipped

Assumptions:

• Propagation velocity – unity

• Clocks - time synchronized.

• Global events - distributed around the network.

• Signal processing – skipped

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Simulations and resultsSimulations and results

Assumptions:

• Ideal case – no redundancy

• Global event – static sources

Assumptions:

• Ideal case – no redundancy

• Global event – static sources

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Simulations and ResultsSimulations and Results

User Interface: User Interface:

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Simulations and ResultsSimulations and Results

Localization Error:Localization Error:

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Simulations and ResultsSimulations and Results

Random deploymentRandom deployment

n = 10, k = 3

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Simulations and ResultsSimulations and Results

Random deploymentRandom deployment

n = 10, e = 20

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Simulations and ResultsSimulations and Results

Manual deployment – Sparse networkManual deployment – Sparse network

(Lerr = 15.52%)

∆ Sensor Nodes

+ Computed position

● Anchor Nodes

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Simulations and ResultsSimulations and Results

Manual deployment – Sparse networkManual deployment – Sparse network

(Lerr = 9.68 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Sparse networkManual deployment – Sparse network

(Lerr = 5.75 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 18.63 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 12.24 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 43.75 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 586.54 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 14.92 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 14.11 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 11.57 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 11.32 %)

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Simulations and ResultsSimulations and Results

Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 11.54 %)

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ConclusionsConclusions

• Investigated positioning of anchor nodes

• Better to deploy anchor nodes at the center of the network

• Less linearity – Better localization

• Placing at right angles

• Real situations may be different

• Investigated positioning of anchor nodes

• Better to deploy anchor nodes at the center of the network

• Less linearity – Better localization

• Placing at right angles

• Real situations may be different

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Future DirectionsFuture Directions

• Implementation on motes.

• Third dimension

• Time synchronization

• Mobile global events

• Implementation on motes.

• Third dimension

• Time synchronization

• Mobile global events

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Questions ?Questions ?

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