Cobra Dane Phased Array Radar 1977 US Air Force; from "Aerospace Power" (Patreon)

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AFSC STAFF FILM REPORT 277

AN OMNIBUS OF CURRENT AF WEAPONS SYSTEMS AND CURRENT RESEARCH AND DEVELOPMENT EFFORTS. PRESENTS A BROAD VIEW OF MAJOR AF PROGRAMS ON... COBRA DANE...

US Air Force Systems Command Special Film Report SFR-277

Originally a public domain film from the National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://en.wikipedia.org/wiki/Cobra_Dane

Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/

The AN/FPS-108 COBRA DANE is a PESA phased array radar installation operated by Raytheon for the United States Air Force at Eareckson Air Station on the island of Shemya, Aleutian Islands, Alaska. This radar system was built in 1976 and brought on-line in 1977 for the primary mission of intelligence gathering in support of verification of the SALT II arms limitation treaty. Its single face radar with a 29 m (95 ft) diameter phased array radar antenna 52.7373°N 174.0914°E faces the Kamchatka Peninsula and Kura Test Range. COBRA DANE operates in the 1215–1400 MHz band.

The "COBRA" designation indicated a General Defense Intelligence Program.

It initially employed a Control Data Corporation Cyber 74 mainframe computer for data processing. Data from the radar is sent to the North American Aerospace Defense Command (NORAD) at Peterson Air Force Base, Colorado. It is also listed as a partner of the NASA Orbital Debris Program Office and works with the Missile Defense Agency, under the control of the 21st Operations Group.

The Cobra Dane radar has been upgraded to be integrated in the Missile Defenses Agency's (MDA) Ballistic Missile Defense System (BMDS). The improvement includes midcourse BMDS sensor coverage by providing acquisition, tracking, object classification, and data that can be used for cueing, launch of interceptor missiles, and course updates of interceptors while retaining the site's legacy intelligence and space track missions. The Air Force maintains responsibility for the Cobra Dane radar operations, maintenance, and sustainment.

Technical Specifications: • Traveling wave tube fed phased-array, all-weather, long-range radar • Provides midcourse coverage for the BMDS. Detects sea-launched or intercontinental ballistic missiles Classifies reentry vehicle and other missile objects. Provides real-time information to Fire Control. Provides tracking of threat ballistic missiles sufficiently accurate to commit the launch of interceptors and to update the target tracks to the interceptor while the interceptor is in flight Details • Cobra Dane has one radar face providing 136°of azimuth coverage. The radar face is approximately 95 feet in diameter; overall radar height is 120 feet. Detects objects out to 2000 miles. It operates in the L-band frequency...

https://en.wikipedia.org/wiki/Phased_array

In antenna theory, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving the antennas. In an array antenna, the radio frequency current from the transmitter is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling to suppress radiation in undesired directions. In a phased array, the power from the transmitter is fed to the antennas through devices called phase shifters, controlled by a computer system, which can alter the phase electronically, thus steering the beam of radio waves to a different direction. Since the array must consist of many small antennas (sometimes thousands) to achieve high gain, phased arrays are mainly practical at the high frequency end of the radio spectrum, in the UHF and microwave bands, in which the antenna elements are conveniently small.

Phased arrays were invented for use in military radar systems, to steer a beam of radio waves quickly across the sky to detect planes and missiles. These phased array radar systems are now widely used, and phased arrays are spreading to civilian applications. The phased array principle is also used in acoustics, and phased arrays of acoustic transducers are used in medical ultrasound imaging scanners (phased array ultrasonics), oil and gas prospecting (reflection seismology), and military sonar systems...