Never before have secondary schools been able to post-process raw satellite data, and now they can do it in real time. This is credited to advances in technology that have recently made the necessary equipment simple, inexpensive, powerful, and available enough for any school to fit into their technology-education curricula. This equipment couples ideally with the emerging utilization of the Internet in secondary schools.

Such precursors to the Internet as the direct satellite broadcasts called Advanced Picture Transmissions (APT) and Weather Facsimile (WeFax), were placed in schools over the past 15 years but never integrated into the curriculum. They provided Graphic Image Files (GIFs), i.e., snapshots of scenes taken by satellites of the Earth below, by polar orbiting (NOAA) and geosynchronous (GOES) satellites, respectively. The operators of the satellites would produce these products on the ground and then uplink them to the same satellites for rebroadcast to the public. Users had no control over what images would be received nor could they enhance them to any notable extent. Recently, the Internet has supplanted this pathfinding service, by enabling the user to request such "canned" images on demand. Yet, due to the enormous amount of data in a single raw image (up to 385 MB), any attempt to access the raw data over the Internet must be severely constrained. Even high-speed connectivity is bogged down by the number of users all too quickly to use the Internet, for accessing anything larger than snapshots. This inherently limits the utility of the Internet services alone.

Now, innovations sponsored by GSFC have enabled us to bring raw, highest resolution, real-time data from the NOAA and GOES satellites to the secondary schools nationwide without compromise, at a price and complexity that they all can afford. This has required advancements in antenna design, a PC-based ingest and image processing system, and a curriculum that meets core learning goals and will be used by the teachers.

Standing Acoustical Wave (SAW) technology was applied to the low noise amplifier inside the antenna feed to better isolate the satellite downlink frequency and remove more of the background noise. This signal is then down-converted inside that feed to a lower frequency, before more noise can be picked up. The lower frequency preserves the signal-to-noise ratio along 300-ft (91-m) of inexpensive coaxial cable. A standard 10-ft (3-m) antenna, used by homeowners for satellite TV, was adapted with this new feed, keeping the antenna costs to a minimum. Next, the expensive ($30k) radio receiver normally employed for access to multiple satellites was replaced by a tailored version on a PC board that can sell for under one thousand dollars. Likewise, the related external components were all designed onto PC boards, so that now the antenna feed plugs right into your PC, with no external components.

The software was rewritten to work on personal computers, which guarantees that the system will get fast-er, better, and cheaper every few months. At this writing, the entire system costs between $5.5k and $8.5k depending on the sophistication of the server computer and economy of scale for software licensing. Compare this to almost $200k for the first systems that NASA used to handle these functions.

The use of these new tools in secondary schools was introduced in 1996 when they still cost $25k. At that time, GSFC augmented the costs for two schools in Maryland and Pennsylvania, and they agreed to use the systems in technology-education programs.

Curricula were developed jointly over the next two years as the technologies and the application software improved and the price came down. Currently, schools in six states, including the Pine Ridge Indian Reservation in South Dakota, are using these systems for academic credit. Students can use their Internet service to get ground truth images of wildfires, ocean currents, rain, snowfall, and the like. They can then locate the same time and place in their large data base of the raw satellite data, and custom enhance their images to match the ground truth. Having developed a suitable algorithm for rainfall where there is Doppler data and bucket measurements, they can now apply that algorithm to anywhere in the Western Hemisphere. Furthermore, using the continuous data from the geostationary satellites (GOES) they can apply their algorithms to the same scene every half hour or so and put it in motion. Now they can watch the rain/snow in motion or the wildfires move as they burn. Using emerging information technologies, they can e-mail their customized film loops to other schools nationwide or beyond. The learning potential is enormous. They learn marketable technology skills in the areas of electronic access of information, post-processing of raw satellite image data, multimedia production, and both electronic and verbal communication skills, while doing really cool science projects. This critical part of the overall program has been a product of cooperation between the educators and NASA, as is essential if it is to be used for academic credits on a nationwide scale.

This work was done by Michael Comberiate of Goddard Space Flight Center, George Isleib of GTI Electronics, and Shawn Terry of Aquila Systems. For further information, access the Technical Support Package (TSP) free on-line at  under the Information Sciences category. GSC-14038

NASA Tech Briefs Magazine

This article first appeared in the January, 2000 issue of NASA Tech Briefs Magazine.

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