Country of origin | United States |
---|---|
No. built | 12 |
Type | early warning radar |
Frequency | VHF |
PRF | 278 Hz |
Pulsewidth | 20 µs |
RPM | 5 |
Range | 250 nautical miles (460 km) |
Diameter | 120 by 50 feet (37 by 15 m) |
Precision | 200 m in range |
Power | 5 MW |
The AN/FPS-24 Radar was a long range early warning radar used by the United States Air Force Air Defense Command. It used a two-frequency signal in order to avoid fluctuation loss, which causes signals on single-frequency radars to fade in and out as the target moves. Reducing this effect results in a much steadier signal.
General Electric was the primary contractor for the design, which operated in the very high frequency (VHF) at 214 to 236 MHz.
Under the Joint Electronics Type Designation System (JETDS), all U.S. military radar and tracking systems are assigned a unique identifying alphanumeric designation. The letters “AN” (for Army-Navy) are placed ahead of a three-letter code. [1]
Thus, the AN/FPS-24 represents the 24th design of an Army-Navy “Fixed, Radar, Search” electronic device. [1] [2]
Twelve systems were built between 1958 and 1962 at various locations around the United States. Problems with the design were revealed during initial testing Eufaula AFS (Eufaula, Alabama) in 1960, resulting in modifications. Additional problems occurred in 1961 when deployment of the first production model at Point Arena Air Force Station in California. revealed bearing problems due to the 85.5 short tons (77.6 t) antenna weight. Failures of the 9 feet (2.7 m) hydrostatic bearing often caused the early closure of some radar sites due to catastrophic damage to the support tower, sail, and feed horn.
Depending on the location of the installation, the radar reflector itself was perched atop one of two different towers: a cast-in-place concrete tower or a metal-sided steel-framed tower both with equal dimensions of 84.5 feet (25.8 m) in height and side dimensions of 60.25 feet (18.36 m) square (63.25 inches (1,607 mm) square including the thickness of corner buttresses). This tower design was also used for the AN/FPS-35 frequency diverse SAGE (Semi-Automatic Ground Environment) search radar built by Sperry Corporation. The prototype installation at Eufaula, Alabama, was perched atop a steel lattice structure tower of shorter, unconfirmed height. Acme Missiles & Construction Corp., Rockville Centre, N.Y. built the radar tower facilities at Missile Master, Pittsburgh Defense Area, Oakdale, PA. [3] Two of the AN/FPS-24 radar installations were covered by a fiberglass dome, protecting the components from the elements. One such installation was at Cottonwood Air Force Station, Idaho. The other was at Mt Hebo Air Force Station, Oregon.
The AN/FPS-24 radar antenna reflector rotated 5 revolutions per minute (a SAGE specification) and was often the cause of interference reported by nearby residents who could hear the radar signal in television and radio broadcasts. At some locations, the radar signal was "blanked" as it passed over television broadcast antenna sites such as Mt. Loma Prieta in the Santa Cruz Mountains, California. However, at DEFCON 3 or higher, the signal was ordered "unblanked" in all directions.
The 7.5 megawatt (maximum power) transmitter ran in normal operation at 5 MW output pulse (nearly 20 microseconds in duration) and was conveyed from the transmitter to the antenna feed horn via a 9 inches (230 mm) diameter rigid coaxial connector. The feed horn consisted of a cross dipole antenna design for both A and B channels.
Subsequent to USAF site closures, some AN/FPS-24 radar units were upgraded to Air Route Surveillance Radar (ARSR) units for USAF-FAA joint surveillance duty.
On May 10, 2016, the Santa Clara County Board of Supervisors voted unanimously to list the Almaden Air Force Station AN/FPS-24 concrete Radar Tower on the County Heritage Resource Inventory, thus giving it official historic status and demolition protection. [4]
The 84.5 foot (25.8 m) concrete buildings that supported most of the AN/FPS-24 antennas were prominent landmarks, [5] and all remain standing.
PAVE PAWS is a complex Cold War early warning radar and computer system developed in 1980 to "detect and characterize a sea-launched ballistic missile attack against the United States". The first solid-state phased array deployed used a pair of Raytheon AN/FPS-115 phased array radar sets at each site to cover an azimuth angle of 240 degrees. Two sites were deployed in 1980 at the periphery of the contiguous United States, then two more in 1987–95 as part of the United States Space Surveillance Network. One system was sold to Taiwan and is still in service.
An active electronically scanned array (AESA) is a type of phased array antenna, which is a computer-controlled antenna array in which the beam of radio waves can be electronically steered to point in different directions without moving the antenna. In the AESA, each antenna element is connected to a small solid-state transmit/receive module (TRM) under the control of a computer, which performs the functions of a transmitter and/or receiver for the antenna. This contrasts with a passive electronically scanned array (PESA), in which all the antenna elements are connected to a single transmitter and/or receiver through phase shifters under the control of the computer. AESA's main use is in radar, and these are known as active phased array radar (APAR).
The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of United States Space Command and operated by the United States Space Force and its functions are:
Cobra Mist was the codename for an Anglo-American experimental over-the-horizon radar station at Orford Ness, England. It was known technically as AN/FPS-95 and sometimes referred to as System 441a; a reference to the project as a whole.
The AN/FPS-117 is an L-band active electronically scanned array (AESA) 3-dimensional air search radar first produced by GE Aerospace in 1980 and now part of Lockheed Martin. The system offers instrumented detection at ranges on the order of 200 to 250 nautical miles and has a wide variety of interference and clutter rejection systems.
The AN/FPS-35 frequency diversity radar was a long range search radar used in the early 1960s. It was one of the largest air defense radars ever produced, with its antenna and supporting structure mounted on one of the largest rolling-element bearings in the world.
Mount Hebo Air Force Station is a closed United States Air Force General Surveillance Radar station. It is located 5.2 miles (8.4 km) east-southeast of Hebo, Oregon, located at the top of 3,154-foot (961 m) Mount Hebo. It was closed in 1980.
The 689th Radar Squadron is an inactive United States Air Force unit. It was last assigned to the 25th Air Division, stationed at Mount Hebo Air Force Station, Oregon. It was inactivated on 30 June 1979.
Fortuna Air Force Station is a closed United States Air Force General Surveillance Radar station. It is located 4.2 miles (6.8 km) west of Fortuna, North Dakota. It was closed in 1979 as a radar station, remaining as a Long-Range Radar (LRR) facility until 1984.
The AN/FPS-16 is a highly accurate ground-based monopulse single object tracking radar (SOTR), used extensively by the NASA crewed space program, the U.S. Air Force and the U.S. Army. The accuracy of Radar Set AN/FPS-16 is such that the position data obtained from point-source targets has azimuth and elevation angular errors of less than 0.1 milliradian and range errors of less than 5 yards (5 m) with a signal-to-noise ratio of 20 decibels or greater.
The AN/FPS-17 was a ground-based fixed-beam radar system that was installed at three locations worldwide, including Pirinçlik Air Base in south-eastern Turkey, Laredo, Texas and Shemya Island, Alaska.
North Truro Air Force Station (AFS) is a closed United States Air Force General Surveillance Radar station. It is located 2.2 mi (3.5 km) east of North Truro, Massachusetts.
Highlands Air Force Station was a military installation in Middletown Township near the borough of Highlands, New Jersey. The station provided ground-controlled interception radar coverage as part of the Lashup Radar Network and the Semi-Automatic Ground Environment network, as well as providing radar coverage for the Highlands Army Air Defense Site. The site's 240 acres (97 ha) is now the Rocky Point section in Hartshorne Woods Park of the Monmouth County Parks System.
The AN/FPS-6 Radar was a long-range height finding radar used by the United States Air Force's Air Defense Command. The AN/FPS-6 radar was introduced into service in the late 1950s and served as the principal height-finder radar for the United States for several decades thereafter. It was also used by the Royal Air Force alongside their AMES Type 80s. Built by General Electric, the S-band radar operated on a frequency of 2700 to 2900 MHz. Between 1953 and 1960, about 450 units of the AN/FPS-6 and the mobile AN/MPS-14 version were produced. The AN/FPS-90 and AN/FPS-116 radars were identical to the AN/FPS-6 except for receiver modifications.
The AN/FPS-20 was a widely used L band early warning and ground-controlled interception radar system employed by the United States Air Force Air Defense Command, the NORAD Pinetree Line in Canada, the USAF CONAD in the continental United States, and a variety of other users. The design started life as the Bendix AN/FPS-3 in 1950, was upgraded to the FPS-20, then spawned over a dozen different variants as additional upgrades were applied. The FPS-20 formed the backbone of the US air defense network through the early Cold War with over 200 units deployed. Most FPS-20 sites were replaced by modern equipment in the late 1960s, although a number were turned over to the FAA, modified for air traffic control use, and became ARSR-60s.
The Avco AN/FPS-26 Radar was an Air Defense Command height finder radar developed in the Frequency Diversity Program with a tunable 3-cavity power klystron for electronic counter-countermeasures (e.g. to counter jamming). Accepted by the Rome Air Development Center on 20 January 1960 for use at SAGE radar stations, the AN/FPS-26 processed height-finder requests (e.g., from Air Defense Direction Centers) by positioning to the azimuth of a target aircraft using a high-pressure hydraulic drive, then "nodding" in either a default automatic mode or by operator command. The inflatable radome required a minimum pressure to prevent contact with the antenna which would result in damage to both (technicians accessed the antenna deck via an air lock.) To maintain high dielectric strength, the waveguide was pressurized with sulfur hexafluoride (SF6), which technicians were warned would produce deadly fluorine if waveguide arcing occurred.
Eufaula Air Force Station is a closed United States Air Force General Surveillance Radar station. It is located 6.4 miles (10.3 km) west of Eufaula, Alabama. It was closed in 1968.
The Solid State Phased Array Radar System is a United States Space Force radar, computer, and communications system for missile warning and space surveillance. There are SSPARS systems at five sites: Beale Air Force Base, CA, Cape Cod Space Force Station, MA, Clear Space Force Station, AK, RAF Fylingdales, UK, and Pituffik Space Base, Greenland. The system completed replacement of the RCA 474L Ballistic Missile Early Warning System when the last SSPAR was operational at then-Clear Air Force Station in 2001.
The AN/FPQ-16 Perimeter Acquisition Radar Attack Characterization System is a powerful United States Space Force phased-array radar system located in North Dakota. It is the second most powerful phased array radar system in the US Space Force's fleet of missile warning and space surveillance systems, behind the more modern PAVE PAWS phased array radar.
The Saugatuck Gap Filler Annex is a decommissioned air defense radar installation previously of the United States Air Force. It served in the vast Cold War era Semi-Automatic Ground Environment (SAGE) air defense system. Of the hundreds of SAGE radars, Saugatuck's is one of, perhaps, two that remain nearly completely intact.
This article incorporates public domain material from the Air Force Historical Research Agency