Over-the-horizon radar

SRI’s Wide-Aperture Radar Facility (WARF) , circa 1970s.

For the U.S. military, SRI pioneered technology to detect objects located thousands of miles beyond the horizon or conventional line of sight. SRI’s Wide-Aperture Radar Facility (WARF) in California was used for decades of over-the-horizon (OTH) research in aircraft, land vehicle, and missile detection; airfield surveillance; ship tracking; terrain mapping; advanced display and signal processing techniques; and remote ocean wave-height measurements.

The WARF design was used to develop the specification for the U.S. Navy’s Relocatable Over-the-Horizon Radar (ROTHR) in Virginia, the U.S. Air Force’s two installations in Maine and Northern California, and the Australian government’s Jindalee experimental OTH radar.

Read our 75th anniversary blog feature

75 years of innovation: Over the horizon radar

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