Over-the-Horizon Backscatter Radar

	Example of OTH coverage area

SRI's Envirotechnical Program supported the U.S. Air Force (USAF) Electronic Systems Division in site selection and environmental compliance for the Over-the-Horizon Backscatter (OTH-B) radar program. The USAF initiative involved the deployment of four pairs of transmit and receive antenna arrays, three in the continental United States and one in the state of Alaska. These units would be used to detect unidentified and potentially hostile aircraft well in advance of their approaching the U.S. 
Due to the size and power of these antenna arrays, the complex analysis of site selection and environmental factors was carried forward by SRI to ensure the most appropriate sites were considered from an operational and environmental perspective. SRI prepared an environmental impact statement and an environmental assessment document for the OTH-B Radar Program.

Aerial photo of SRI Wide Aperture Radar Facility Array at Los Banos, California		Two digitally controlled and steerable receiving antennas