College of Engineering Anchor Nodes Placement for Effective Passive Localization Karthikeyan...

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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• Architecture• Architecture

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• Limitations

• Deployment

• Short lifetime

• Unmanned

• Limitations

• Deployment

• Short lifetime

• Unmanned

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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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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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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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• Localization Systems

• Centralized

• Distributed

• Localization Systems

• Centralized

• Distributed

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• 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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• 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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• 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


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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


• More accurate


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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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• Disadvantages

• Centralized

• Not suitable for indoor applications

• Disadvantages

• Centralized

• Not suitable for indoor applications

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• Event detection

• Projected distances

• Localization

• Distance Matrix

• SVD

• Event detection

• Projected distances

• Localization

• Distance Matrix

• SVD

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• 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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Localization Error:Localization Error:

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Random deploymentRandom deployment

n = 10, k = 3

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Random deploymentRandom deployment

n = 10, e = 20

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Manual deployment – Sparse networkManual deployment – Sparse network

(Lerr = 15.52%)

∆ Sensor Nodes

+ Computed position

● Anchor Nodes

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(Lerr = 9.68 %)

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(Lerr = 5.75 %)

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Manual deployment – Dense networkManual deployment – Dense network

(Lerr = 18.63 %)

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(Lerr = 12.24 %)

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(Lerr = 43.75 %)

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(Lerr = 586.54 %)

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(Lerr = 14.92 %)

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(Lerr = 14.11 %)

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(Lerr = 11.57 %)

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(Lerr = 11.32 %)

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(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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