Streaming Sensor Data from Space: Acquiring and Managing Direct Broadcast Satellite Data for Sites of the Long Term Ecological Research Network
John Vande Castle, Mark Servilla
Last modified: 2008-08-21
Satellite sensor data provide important information over extensive areas but are usually not considered in the realm of real-time sensor data since most satellite information is used after post-processing, from archive centers days months or longer after initially acquired. However, direct broadcast data transmission from environmental satellite systems, particularly the MODIS sensor of the Terra and Aqua spacecraft and the AVHRR sensor of the NOAA series spacecraft provide real-time environmental data with every satellite overpass. With the advance in processor speed and data storage technologies, processing the raw satellite data into usable data products is now achieved within minutes of a satellite overpass. Specialized direct readout processing systems are able to downlink the raw sensor data, store and reprocess the data in near real-time. These systems can be configured for automated acquisition and processing to provide standardized data products within minutes of acquisition. This provides an important data source for ecological disturbance events including hurricanes, storms, flood, fire and other applications. A collaboration between the Center for Rapid Environmental Assessment and Terrain Evaluation and the Long Term Ecological Research Network Office acquires, processes and archives these data for use by scientists and researchers. Data products produced from the raw sensor data are transferred to the data storage systems of web servers in near real-time for access. Automated generation and harvesting of metadata from the data products are updated to servers as the data are produced. This paper describes the flow of raw data from the satellite sensor to standard products for the near real-time archive and the generation of metadata to provide for search capability of the data.