Over-the-horizon radar

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.