Oplægget blev holdt ved InfinIT-arrangementet "Temadag om trådløse sensornetværk", der blev afholdt den 17. november 2010. Læs mere om arrangementet her: http://infinit.dk/dk/hvad_kan_vi_goere_for_dig/viden/reportager/vaer_smart_-_taenk_traadloest.htm

1. The PermaSense Project
Wireless Sensor Networks for
Extreme Environments
Jan Beutel
ETH Zurich

2. 19.11.2008

3. 16.7.2003
Photo: Bruno Jelk

4. 16.7.2003
Rockfall release
mechanisms and their
connection to time and
climate (change) are
not understood
Foto: Bruno Jelk

5. PermaSense – Aims and Vision
Geo-science and engineering collaboration aiming to:
– provide long-term high-quality sensing in harsh
environments
– facilitate near-complete data recovery and near real-time
delivery
– obtain better quality data, more effectively
– obtain measurements that have previously been impossible
– provide relevant information for research or decision
making, natural hazard early-warning systems

6. Understanding Root Causes of Catastrophes
Eiger east-face rockfall, July 2006, images courtesy of Arte Television

7. Our patient does not fit
into a laboratory

8. So the laboratory has
to go on the mountain

9. PermaSense Deployment Sites 3500 m a.s.l.
A scientific instrument for precision sensing and data recovery in
environmental extremes

10. PermaSense – Key Architectural Requirements
• Support for ~25 nodes
• Different sensors
– Temperatures, conductivity, crack
motion, ice stress, water pressure
– 1-60 min sensor duty-cycle
• Environmental extremes Relation to other WSN projects
– −40 to +65° C, ΔT ≦5° C/min
– Rockfall, snow, ice, rime,
• Comparable to other environmental
avalanches, lightning monitoring projects
– GDI [Szewczyk], Glacsweb [Martinez],
Volcanoes [Welsh], SensorScope [Vetterli],
• Near real-time data delivery Redwoods [Culler]
• Lower data rate
• Long-term reliability
– ≧99% data yield • Harsher, higher yield & lifetime
– 3 years unattended lifetime • Data quality/integrity

11. Sensor Network Technology

12. PermaSense – System Architecture
• Support for multiple sensor types
• Wireless sensor network
– Ultra low-power data gathering (Dozer)
• Base station
– Embedded Linux (Gumstix)
– 4 GB local storage, data duplication
– WLAN/GPRS connectivity, backup modem
– Solar powered
• Data backend
– Streaming interface with metadata (GSN)
– Standard internet services for monitoring

13. The Big Picture – Network System Integration

14. At the Core – Low-power Wireless Sensors
• Static, low-rate sensing (2 min)
• Temperature profiles,
crack meters, resistivity
• 3 years operation
• < 0.1 Mbyte/node/day

15. Based on Recent Research Achievements
• Dozer ultra low-power data gathering system
– Beacon based, 1-hop synchronized TDMA
– Optimized for ultra-low duty cycles
– 0.167% duty-cycle, 0.032mA
contention
window data transfer beacon
jitter
slot 1 slot 2 slot k time [Burri – IPSN2007]
• System-level, round-robin scheduling
– “Application processing window” between data transfers and beacons
– Custom DAQ/storage routine
Application processing window
slot 1 slot 2 slot k time

16. PermaSense – Sensor Node Hardware
• Shockfish TinyNode584
– MSP430, 16-bit, 8MHz, 10k SRAM, 48k Flash
– LP Radio: XE1205 @ 868 MHz
• Waterproof housing and connectors
• Protective shoe, easy install
• Sensor interface board
– Interfaces, power control
– Temp/humidity monitor
– 1 GB memory
• 3-year life-time
– Single Li-SOCl2 battery, 13 Ah
– ~300 A power budget

17. Sensors Contribute to Power Consumption

18. Ruggedized for Extreme Environments

19. PermaDozer – Total Power Performance Analysis
1/120 sec
1/30 sec
148 uA average power

20. Infrastructure
&
Data Management
Technische Informatik und Kommunikationsnetze
Computer Engineering and Networks

21. Long-haul Communication – Directional WLAN
• 7.5 km from weather radar on
Klein Matterhorn
• Leased fiber/DSL from Zermatt
Bergbahnen AG
• Commercial components
(Mikrotik)
• Weatherproofing

22. PermaSense – Base Station Situation

23. Base Station - Embedded Linux & WLAN Router
Gumstix Verdex
WLAN Router
TinyNode
GSM
EMP Protectors
IP68 Enclosure and Connectors

24. Basic On-Site Support – Power, Weather, Camera
• Mobile power/deployment box
– 12V photovoltaic system
– Surge protection
– Remote switchable power channels (reset)
– Internal humidity/temperature monitor
– 220V converter for deployment work
• Weather station
• Webcam

25. Data Management – Online Semantic Data
• Global Sensor Network (GSN)
– Data streaming framework from EPFL
– Organized in “virtual sensors”, i.e. data types/semantics
– Hierarchies and concatenation of virtual sensors enable on-line processing
– Translates data from machine representation to SI values
– Adds metadata
Import from field GSN GSN Web export
Private Public
Metadata
==============
Position
Sensor type
…

26. Multi-Site, Multi-Station Datenmanagement

27. Central Web-based Data Access

28. PermaSense Sensors – Sensor Rod Example

29. Geoscience: Fast Localized Thaw by Advection
Near-surface temperature/conductivity
Combination with lab experiments and models

30. Installation Work on Matterhorn 09/2007
PermaSense installation 2007, images courtesy of Arte Television

31. PermaSense Sensors – Crack Meter Example

32. Geoscience: Cryogenic Rock Movement/Weathering
Moisture saturation and freezing
dynamics captured by sensor rod
Resistance [MOhm]
Dilatation data with cleared thermal signal
Temperature [°C]
Temperature [°C]
Distance [mm]
Distance
[mm]
Temperature [°C]

33. Experiences…

34. Physical Reality Impacting Performance
Ambient Temperature
DAQ Duration
Storage Duration
time
Watchdog Resets

35. Experiences – First Behavioral Data from the Field
System Outage
# Lost Packets
Loss of Connectivity
Battery Voltage & Temperature

36. 3 Months Later – Increasing Runtime Errors
# Lost Packets
System Outages
Loss of Connectivity
Node Reboot

37. Data Quality and Integrity
• Since 07/2008: 95„874„376 data points
• Inconsistencies
– Between timestamps and sequence numbers
• Duplicates
• Data gaps
– Sporadic
– Systematic
Installation & Service 2008 Service 2009 Revision / Extension June 2010
Sensornode 20 - 22 new installiation

38. Key PermaSense Challenges
System Integration Correct Test and Validation
Actual Data Interdisciplinary Team

39. • ETH Zurich
– Computer Engineering and
Networks Lab
• University of Zurich
– Department of Geography
• University of Basel
– Department Computer Science
Interested in more?
http://www.permasense.ch