Sensor Networks&

GLACSWEBGLACSWEB

Kirk MartinezKirk Martinez

IAM GroupIAM Group

ECSECS

Why sense the environment?

• Studying global environmental changes requires massive data collection…

• Coarse but large systems exists for weather prediction

• but deep oceans, ice caps, microclimates are less covered

Challenges

• reusable cheap components, self-configuring

• robust communications

• autonomous and adaptive behaviour

• extensible ad-hoc networking

• low power

• to enable data fusion, data must be accessible: need a semantic sensor web

Who is doing this too?• Jet Propulsion Lab

– use the term "sensor webs"

Nextwave Envisense Centre

• Glaciers - Glacsweb

• Flooding - Floodnet

• Coastal erosion - Seacoas

Glacsweb Aims and Objectives

• To monitor glacier dynamics as a contribution to the study of ‘Global Warming’ and glaciology

• To develop a pervasive sensor network

• To produce generic components and expertise useful in other environments

GLACSWEB

Pervasive computing

Supraglacial data Subglacial data

Test Site

map

Field siteField site

expected movement in a year

Base Station

reference station

Ice

Sediment

13m

10m

7m

3m

Sometimes the only way to get your equipment in is to employ a helicopter….

Understanding the Subglacial Environment

• Ground Penetrating Radar

• Drilling & till sampling

• Borehole camera

GPR interpretation

T1T2

T0

T3

L1L2

L3

10m0

N

Subglacial Channel?

Ice flow

“strong” reflection

hot water drilling

Ice hole depth

10m0

N

Ice flow72m

Water drained

70m

76m

80m

Water filled

55m65m

82m

56m62m 63m

75m>38m

GPR survey 50MHz

“strong” reflection

Subglacial Channel

Probes in iceProbes in till

Till sampled

System overview

ReferenceStation (RS)

Base Station(BS)

GLACIER ROCKS Cafe

PR

TILL

PR

PR

PR

ICE

Long range comms(466 MHz)

RCRC

RC

RCRC

Short range comms(433 MHz)

PR = ProbesRC = Receivers

Probes

• Plastic case (10cm long)• PIC microcontroller• Radio Transceiver• A/D and amplifiers• Batteries• Sensors: tilt, temp, pressure• Real time clock

I2C

7 56

121110

8 4

21

9 3

Realtime Clock

Power supply(switch-mode)

Micro-controller

(16F876)

Temperaturesensor

Pressuresensor

Orientationsensor

FLASHROM(16kB)

Transceiver(868 MHz)

RS232

Short rangecommunication

7.2V

bat

tery

(Lith

ium

Thi

only

Chl

orid

e)

Probe subsystems

Probe pressure tests in Oceanography

Base station

• Measure snow levels, temp, box tilt, bat V

• Radio links to Ref station and probes

• DGPS• Large power

supply and solar panel

Transceiver(868 MHz)

Micro-controller

(16F877)

12V

bat

tery

(Se

ale

d Le

ad-a

cid)

I2C

7 56

121110

8 4

21

9 3

Realtime Clock

Power supply(switch-mode)

FLASHROM(32kB)

GPS controller(16F628)

GSM controller(16F628)

Radio modem(466 MHz)

Short rangecommunication

Long rangecommunication

GPS module(Legacy-H)

Snow sensor(16F628)

RS

232

Base Station

Reference station• Small Linux server• ISDN line• Backup of all data• Gets all DGPS data• Deposits data on

Southampton server

Radio modem(466 MHz)

Long rangecommunication

GPS module(Legacy-H)

3D Positioning (1 Probe)

Base Station(BS)

GLACIER

TILL

PR

ICE

RCRC

RC

RCRC

High energy pulses

• Distance from PR to RC = time taken for signal to reach RC• Position of PR calculated via trilateration

PCBs

Hours Probe Base Station Reference Station

0000 Data logging - -

0400 Data logging - -

0800 Data logging - -

1200 Data logging GPS logging GPS logging

1600 Communication Communication Communication

1900 - - Data transfer

2000 Data logging - -

System Timeline

System on times: Data logging - 11 secondsGPS logging - 20 minutesCommunication - 180, 300, 600 seconds (PR, BS, RS)Data transfer - when completed

testing and construction of the prototype probes

probe deployment in water-filled hole

probe deployment in part water-filled hole

Preliminary results

0.70

0.75

0.80

0.85

31/0

7/03:

00

01/0

8/03:

00

02/0

8/03:

00

03/0

8/03:

00

04/0

8/03:

00

05/0

8/03:

00

06/0

8/03:

00

07/0

8/03:

00

Date (dd/mm/yy:hh)

Tem

per

atu

re (

Cel

ciu

s)

8.00

10.00

12.00

14.00

16.00

18.00

20.00

31/0

7/03:

00

01/0

8/03:

00

02/0

8/03:

00

03/0

8/03:

00

04/0

8/03:

00

05/0

8/03:

00

06/0

8/03:

00

07/0

8/03:

00

Date (dd/mm/yy:hh)

Pre

ss

ure

(p

si)

-75.50

-75.00

-74.50

-74.00

-73.50

31/07

/03:0

0

01/08

/03:0

0

02/08

/03:0

0

03/08

/03:0

0

04/08

/03:0

0

05/08

/03:0

0

06/08

/03:0

0

07/08

/03:0

0

Date (dd/mm/yy:hh)

X-a

xis

Tilt

(d

egre

es)

1.50

2.00

2.50

3.00

3.50

31/0

7/03:

00

01/0

8/03:

00

02/0

8/03:

00

03/0

8/03:

00

04/0

8/03:

00

05/0

8/03:

00

06/0

8/03:

00

07/0

8/03:

00

Date (dd/mm/yy:hh)

Y-a

xis

Tilt

(d

egre

es)

Battery Voltage (Base)

• Solar panel seems to have provided more power than was used

11

11.5

12

12.5

13

13.5

14

14.5

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67

Series1

Temperature & tilt of the base station

-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

10/10/03 17/10/03 24/10/03

Date

X-a

xis

tilt

(d

eg

ree

s)

-24.0

-23.0

-22.0

-21.0

-20.0

Y-a

xis

tilt

(d

eg

ree

s)

-6.00

-4.00

-2.00

0.00

2.00

4.00

6.00

10/10/03 17/10/03 24/10/03

Date

Tem

per

atu

re (

Cel

ciu

s)

Summary & Conclusions

• Designed, built, tested and deployed 9 sensor probes, Base Station and Reference station

• Some things are difficult to calculate beforehand

• Lots of ad-hoc design and tuning is needed during installation

Future development

• Smaller probe electronics

• Lower frequency probe communications

• Probe positioning system

• Web site data plots

Credits

• Royan Ong, Joseph Stefanov, Al Riddoch, Harvey Royan Ong, Joseph Stefanov, Al Riddoch, Harvey Rutt, Rutt, ECSECS..

• Jane K. Hart, Sue Way, GeographyJane K. Hart, Sue Way, Geography• Ian Marshall, Ian Marshall, BTExactBTExact;;• Nathan Boyd and John Argirakis, Nathan Boyd and John Argirakis, InteliSYS InteliSYS

• Funded by:Funded by:

the Royal Society & DTI's Nextwave programme.the Royal Society & DTI's Nextwave programme.

www.glacsweb.orgwww.glacsweb.org