The Pilot Weather Advisor (PWA) system is an automated satellite radio-broadcasting system that provides nearly realtime weather data to pilots of aircraft in flight anywhere in the continental United States. The system was designed to enhance safety in two distinct ways: First, the automated receipt of information would relieve the pilot of the time-consuming and distracting task of obtaining weather information via voice communication with ground stations. Second, the presentation of the information would be centered around a map format, thereby making the spatial and temporal relationships in the surrounding weather situation much easier to understand. Starting in the early 1990s, the PWA system was developed by ViGYAN, Inc., under the NASA SBIR program. The system recently became commercially viable and was sold to WSI, a leading provider of weather services in aviation. The system is now marketed under the brand name “WSI InFlight.”

The PWA system includes a ground processor (see figure), wherein a computer running special-purpose software converts, compresses, and schedules the weather data. The compressed data are then transmitted through a ground station to a geosynchronous satellite, from whence they are broadcast to cover the continental United States. The signal is acquired by a light, low-drag antenna mounted on a subscriber’s aircraft, and is then interpreted by an equally lightweight receiver. In the cockpit of each InFlight equipped aircraft, the data are processed, by use of other special-purpose software and hardware, into an easy-to-interpret graphical display. The display is presented on a portable or panel-mounted unit. The data, which include graphical meteorological aviation reports (METARs), terminal aerodrome forecasts (TAFs), and Next Generation Weather Radar (NEXRAD) images, as well as other weather products, are updated every five minutes.

Accessibility of the system to light general aviation was a design goal because such airplanes are more susceptible to changes in weather than are larger, higher- flying airplanes. The lightweight, low-drag nature of the PWA airborne components and the relatively low cost of acquiring and using the equipment make the PWA system affordable for incorporation into lower-cost single-engine airplanes, which constitute the largest segment of the aviation market. Hence, success of this design goal was achieved. In addition, the PWA system is also attractive for use in higher-priced general-aviation airplanes because the weather information that it provides covers longer ranges than do onboard weather radar and lightning detectors with which such airplanes are often equipped.

This work was done by Glenn Lindamood and Konstantinos (Gus) Martzaklis of Glenn Research Center; Keith Hoffler, Damon Hill, Sudhir C. Mehrotra, and E. Richard White of ViGYAN, Inc.; Bruce D. Fisher of NASA Langley Research Center; Norman L. Crabill of Aero Space Consultants; and Allen D. Tucholski of Akima Corp. For further information, access the Technical Support Package (TSP) free online at under the Electronics/Computers category.

Inquiries concerning rights for the commercial use of this invention should be addressed to:

NASA Glenn Research Center
Innovative Partnerships Office
Attn: Steve Fedor
Mail Stop 4–8
21000 Brookpark Road
Cleveland, Ohio 44135

Refer to LEW- 17702-1

NASA Tech Briefs Magazine

This article first appeared in the May, 2006 issue of NASA Tech Briefs Magazine.

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