What is a Sensor Web ?

Abhinav RoongtaWireless Information Networking Group

University of FloridaMarch 3, 2004

Outline

• Sensor Web– Definition– Basics– Organization– Potential – Current applications

Introduction

Single transducer monitors and records particular aspect of environment.Little information regarding dynamics.

Correctly configured group can extract spatio-temporaldynamics.

Definition

• According to NASA New Technology Report on Sensor Webs, “ The Sensor Web consists of a system of intra-communicating, spatially distributed, sensor pods that can be deployed to monitor and explore new environments “.

Sensor Web Basics

• Communication occurs wirelessly• Each pod consists of two modules

– Transducers that convert environmental parameters into electrical signals.

– Second module• Telecommunication capabilities• Power sources• Energy harvesting devices• Computation devices

Sensor Web Instrument

Example of Sensor Web Pod

Radio TransmitterReceiverMicrocontrollerLithium batteryTwo sensorsTotal mass 50 g.

Sensor Web Basics

• Goal is to extract knowledge and– Adapt – React

• Sharing of information among pods gives macro-intelligence

• Global information sharing permits– Resource management– Self modifying behaviour

Sensor Web Basics

• Wireless communication between pods is omni-directional.

• Information hopping from pod to pod.

• Information at each pod comes through– Direct measurement taken by local sensors at

each pod.– Information gathered by other pods and

communicated throughout the web.

Multi-Hopping and Power Efficiency

Sensor Web vs Sensor Networks

• Information gathered by one pod is shared and used by other pods.

• Sensor networks collect data while Sensor Webs modify their behaviour on basis of collected data.

Sensor Web Organization

Sensor Web Organization

• Deployment of new pods possible.

• No preferred direction of information flow.

• Radio traffic is bi-directional.

• End user interacts through the mother pod.

In Situ Sensor Webs vs. Other Monitoring Techniques

• Sensor Web provides– Direct, proximity measurements over large

spatial scale with immediate value– Continued, virtual presence in area– Access to areas not reachable by remote

measurements.

In Situ Sensor Web Requirements

• Power Minimization

• Bandwidth minimization

• Cost minimization.

Sensor Web Deployments

Seven Transducers, Commercial Transceiver (16 Mhz), 8 V battery.

Sensor Web Deployments

Key Concepts Demonstrated

• Individual pods reintegrate themselves

• Minor hardware repairs & upgrades performed on some pods while rest of the web is running

• Isolated pods seek the network & integrate themselves

• Synchronization of pods

References

• K. A. Delin and S. P. Jackson, “ The Sensor Web: A New Instrument Concept” SPIE Symposium on Integrated Optics, Jan 2001.

• K. A. Delin, “The Sensor Web: A Macro Instrument for Coordinated Sensing” appeared in Sensors Vol. 2, 2002.

• http://sensorwebs.jpl.nasa.gov.