SF44A-01 INVITED 16:00h
Sensor Webs in the Wild
In October 2001, a new era in wireless sensor systems began when the NASA/JPL Sensor Web deployed at the Huntington Botanical Gardens in Southern California went online. For the first time, it was possible for a person with nothing more than a computer, an Internet connection, and a standard browser to watch streaming, real-time data generated by an ad hoc wireless networked system permanently embedded in an outdoor environment. Unlike other wireless sensor networks, the central purpose of a Sensor Web system is to extract knowledge from the data it collects and use this information to intelligently react and adapt to its surroundings. It acts as a single, distributed instrument that links a remote end-user's cognizance with the observed environment. The Sensor Web's capabilities are useful in a diverse set of outdoor applications ranging from precision agriculture to perimeter security to effluent tracking. Wireless networked systems, and Sensor Webs in particular, are only just beginning to change the ways in which we can sense, monitor, and control large spatial areas. Here, we both explore the possibilities that Sensor Webs bring to Earth science and examine several recent deployments (real-time data streams from these sites are available at http://sensorwebs.jpl.nasa.gov/).
http://sensorwebs.jpl.nasa.gov/
SF44A-02 16:30h
Optical Remote Sensing of the Nearshore: The Argus Program
The past decade has seen much increased interest in the development and deployment of environmental sensor networks or observatories. A part of the interest is due to technological developments, including high-bandwidth communications, that make multi-user common-access sampling programs feasible and cost-effective. However, an important component of the interest is due to recent discoveries in nonlinear dynamics systems and chaos, and the recognition that long time series observations can reveal physics that could not be observed from their short time series predecessors. In the field of nearshore processes, the study of the beach area out to 10 m water depth, the Coastal Imaging Lab at Oregon State University has developed and operated a long-term observing system called the Argus Program, based on shore-based optical imaging. Beginning in 1992, collections have been made hourly of a range of beach bathymetry, morphology and fluid dynamic measurements. The program includes twelve stations, sited around the world, and an archive that currently includes 77 site-years of data. This talk will address issues of developing and operating the Argus Program and of dealing with a widely distributed user group.
http://cil-www.coas.oregonstate.edu:8080
SF44A-03 16:50h
Infrasonic Monitoring of Eruptions at Tungurahua Volcano, Ecuador using a Wireless Sensor Network
Wireless sensor networks, consisting of small, low-power devices integrating a modest amount of CPU, memory, and wireless communication, could play an important role in volcanic monitoring applications. Wireless sensor nodes have lower power requirements, are easier to deploy, can can support a larger number of sensors distributed over a wider area than wired arrays currently used in many campaign studies. Using long-distance wireless links, data could be monitored in real time, avoiding the need for manual data collection from remote stations. We developed and deployed a wireless infrasonic sensor array at Volc\'{a}n Tungurahua, Ecuador, in July 2004. This network consisted of three wireless sensor nodes that digitized infrasonic signals, transmitting data to a remote base station. The sensors are based on the Mica2 mote platform, which integrates a 7.3 MHz Atmel Atmega128L embedded controller with 4 KB of RAM and 128 KB of ROM. The Mica2 uses a low-power, single-chip radio, the Chipcon CC1000, capable of transmitting data at 22.5 kbps with an outdoor range of approximately 100 m. The node measures 5.7 cm x 3.2 cm x 2.2 cm and is operated on 2 AA batteries, with a lifetime of about 157 hours without duty-cycling the radio or CPU. These nodes run a specialized operating system called TinyOS that is specifically designed for wireless embedded devices. Each sensor node sampled infrasonic signals continuously at 102 Hz, transmitting data over a short-range radio link to a local aggregator node. The aggregator relayed the data over a 9 km wireless link to a laptop station at the volcano observatory, using a pair of spread-spectrum FreeWave modems and 9 dBi Yagi antennas. Nodes were time-synchronized using a separate GPS receiver that transmitted periodic timestamp messages, allowing our data to be later correlated with signals acquired at a nearby wired seismoacoustic sensor array. During the deployment, we collected over 54 hours of continuous data which included at least 9 verified explosions. In addition to continuous sampling, we have developed a distributed event detector that automatically triggers data transmission when a well-correlated signal is received by multiple nodes. This approach greatly reduces radio bandwidth and energy consumption, and we plan to deploy this new system as part of a larger wireless sensor array in the near future.
http://www.eecs.harvard.edu/~werner/projects/volcano/
SF44A-04 17:10h
Glacsweb: an environmental sensor network
Environmental sensor networks provide an exciting opportunity to remotely study and monitor a range of environments. This is particularly important in remote or hazardous environments where many studies are hampered by inaccessibility. In addition, more accessible environments could be monitored on an unprecedented scale. The potential advances to environmental sciences could be as great as the revolution produced by the development of remote sensing during the 1970's. The aim of the GlacsWeb project is to build an environmental sensor network to understand glacier dynamics in response to climate change. This was undertaken to collect data from sensor nodes (probes) within the ice and the till (subglacial sediment). The wireless probes were designed to move freely like natural stones. Data is also collected from the surface of the glacier (position, weather, image). The data is sent to the Sensor Network Server where it is combined with large scale data from maps and satellites. In this way, specific data from the unique sensor nodes (which reflect point data) are combined with larger scale data to understand the glacier as a whole. The data was collected from within the ice by radio communications specifically designed for this environment; with increased power and using a 433Mhz frequency. The GlacsWeb system is composed of custom-built probes, a Base Station on the ice surface, a Reference Station (2.5 km from the glacier with mains electricity) and the Server based in Southampton. A differential GPS is used to track the base station's movement and recordings are made each day. The whole system operates automatically and data is fetched daily and sent to a web server for analysis. An initial system was installed in 2003 and an improved system was built and deployed in Jostedalsbreen, Norway in 2004. Advances were made in miniaturisation, low power design, networking and autonomous behaviour. Extra sensors were also added which measure probe stress and external conductivity. The results from the most recent system will be presented and discussed.
http://www.glacsweb.org
SF44A-05 17:30h
Considerations for Future Complexities in Environmental Sensor Arrays
A review of current data collection, processing, and archiving from regional seismograph arrays, regional geodetic arrays, and ocean-wide meteorological and oceanographic arrays leads to conclusions regarding the future directions of environmental arrays. New technologies facilitate growth and increasing complexity of sensor arrays and the globalized sharing of data. There are several areas that should be considered while the arrays are being built: (1) Standardization in sensor deployment. Similar types of sensors are currently deployed by a variety of organizations. It is important to develop a standardization process followed by detailed documentation of sensor installations. This documentation should as accessible as the corresponding data. (2) Adherence to robustness, security, and flexibility in data collection. Heterogeneous data telemetry methods continue to provide flexibility. It is important to not limit telemetry options. Promising developing technologies, such as wireless, should be considered immature. Redundancy in data collection and in data back up is critical. Data back up can be as simple as flash memory powered by batteries. A further step in data back up would be a many node data archival and sharing system. (3) Real-time availability of data that has been quality controlled and corrected for instrument response. Sensor calibration information is critical. As sensor arrays are constructed it is important to develop data processing methods that allow real-time correction for instrument response. Calibration information should be easily accessible. Sensor vendors can help by taking an active responsibility in the maintenance of globally available calibration databases.