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

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

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3 Photo: Bruno Jelk

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

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 40 to +65 C, ΔT 5 C/min Rockfall, snow, ice, rime, avalanches, lightning Near real-time data delivery Long-term reliability 99% data yield 3 years unattended lifetime Relation to other WSN projects Comparable to other environmental monitoring projects GDI [Szewczyk], Glacsweb [Martinez], Volcanoes [Welsh], SensorScope [Vetterli], Redwoods [Culler] Lower data rate Harsher, higher yield & 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 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

14 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

15 PermaSense Sensor Node Hardware Shockfish TinyNode584 MSP430, 16-bit, 8MHz, 10k SRAM, 48k Flash LP Radio: 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-SOCl 2 battery, 13 Ah ~300 A power budget measured avg. current consumption ~148 µa

16 Sensors Contribute to Power Consumption

17 Ruggedized for Extreme Environments

18 PermaDozer Total Power Performance Analysis 1/120 sec 1/30 sec 148 ua average power

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

20 PermaSense Base Station Situation

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

22 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

23 Imaging

24 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

25 Multi-Site, Multi-Station, Multi-Revision Data

26 Central Web-based Data Access

27 PermaSense Sensors Sensor Rod Example

28 PermaSense Sensors Crack Meter Example

29 PermaSense Sensor Data Results

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

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

32 Experiences Technische Informatik und Kommunikationsnetze Computer Engineering and Networks

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

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

35 3 Months Later Increasing Runtime Errors System Outages # Lost Packets Loss of Connectivity Node Reboot

36 Data Quality and Integrity Since 07/2008: data points Inconsistencies Between timestamps and sequence numbers Duplicates Data gaps Sporadic Systematic Installation & Service 2008 Service 2009 Revision / Extension June 2010 Sensornode new installiation

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

38 PermaSense collaborations

39 ETH Zurich Computer Engineering and Networks Lab University of Zurich Department of Geography University of Basel Department Computer Science Interested in more?