Over-the-Horizon Radar


	Engineering & Systems Division

	Sensing

	Geospace
	Envirotechnical
»	Remote Sensing
	–	Ocean Littoral Env.
	»	OTH Radar
	–	GPS Calibration
	–	OLMS
	Penetrating Radar

Since the early 1960s, working closely with various governmental agencies, we have contributed significantly to every technology breakthrough in over-the-horizon radar research and development, and are the only company operating its own OTH research radar, the Wide Aperture Research Facility (WARF). We have pioneered the development of OTHR counter-drug surveillance, demonstrating detection and tracking to 1600 nautical miles. In other recent work we developed an advanced maneuvering target tracker and completed a cost-effective conversion to a semi-automated, real-time radar system with the ability to remotely display target data anywhere in the world.

Wide Aperture Research Facility

WARF, a high-resolution, bistatic HF skywave radar system is located at two major field sites in the central valley of California. The WARF transmitter site is near Lost Hills, California and the receiver site is near Los Banos, California, about 100 nmi north of the transmitter site. WARF is the only testbed in the United States devoted to advanced technology R&D for OTH radars across a wide range of activities. In the past WARF was used to develop the long-range detection and tracking technology that became the foundation of operational OTH radar programs for the U.S. Air Force, the U.S. Navy, and the government of Australia.

High power antenna arrays at Lost Hills consist of 16 log-periodic elements that transmit over the frequency range of 6-28 MHz. Average effective radiated power is 20 MW in a nominal 6° beamwidth. Boresights of 120° and 270° are available.

antennae A digitally controlled and steerable receiving antenna is arrayed over a distance of 2.3 km to receive the HF signals transmitted from Lost Hills and returned from targets via the ionosphere to Los Banos. The nominal beamwidth is one-half degree.

oth concept OTH Radar concept showing separate transmit and receive sites that use the ionosphere to reflect energy back to the earth. Simultaneous tracking of separate targets is performed. (Larger image)

Nominal WARF OTHR coverage area (1000 km to 3000 km range), boresighted on 120° true north. Both land and ocean surveillance research can be conducted.

operations room WARF Operations and Control Center at the receive site near Los Banos, CA. Various consoles enable full management of radar propagation, data recording, surveillance area selection, detection, and tracking.

Testbed Technology and Applications

The frequency-modulated continuous-wave (FMCW) waveform.
Wide-aperture (2.3 km) receiving-antenna array.
Automatic detection and tracking of aircraft and ships.
Sea-state monitoring and hurricane tracking.
Tracking of individual ground vehicles, including trains and trucks.
Tracking of ballistic missiles.
Track-while-scan methodologies.
Advanced tracking using dynamic programming and artificial intelligence.
Real-time ionospheric monitoring and propagation management.
Dynamic, real-time, interactive display technology.
New patent pending real-time capability for simultaneous automatic detection and tracking of multiple target types. Examples are ships, aircraft, and missiles, with separate data monitors and trackers, but a unified geographic situation display.

Contact

Email: oth@mail.esd.sri.com

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