Radar is a system that uses radio waves to determine the distance (ranging), direction, and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain.
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.
Semi-active radar homing (SARH) is a common type of missile guidance system, perhaps the most common type for longer-range air-to-air and surface-to-air missile systems. The name refers to the fact that the missile itself is only a passive detector of a radar signal—provided by an external ("offboard") source—as it reflects off the target. Semi-active missile systems use bistatic continuous-wave radar.
The RCA 474L Ballistic Missile Early Warning System was a United States Air Force Cold War early warning radar, computer, and communications system, for ballistic missile detection. The network of twelve radars, which was constructed beginning in 1958 and became operational in 1961, was built to detect a mass ballistic missile attack launched on northern approaches [for] 15 to 25 minutes' warning time also provided Project Space Track satellite data.
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).
A pulse-Doppler radar is a radar system that determines the range to a target using pulse-timing techniques, and uses the Doppler effect of the returned signal to determine the target object's velocity. It combines the features of pulse radars and continuous-wave radars, which were formerly separate due to the complexity of the electronics.
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.
The Orfordness transmitting station was a major radio broadcasting facility at Orford Ness on the Suffolk coast in the United Kingdom able to broadcast to much of Europe. It closed in May 2012 after more than 30 years of service. In 2017 Radio Caroline started broadcasting from the site, though not with the same intended coverage of an audience in Europe as the original station.
Over-the-horizon radar (OTH), sometimes called beyond the horizon radar (BTH), is a type of radar system with the ability to detect targets at very long ranges, typically hundreds to thousands of kilometres, beyond the radar horizon, which is the distance limit for ordinary radar. Several OTH radar systems were deployed starting in the 1950s and 1960s as part of early-warning radar systems, but airborne early warning systems have generally replaced these. OTH radars have recently been making a comeback, as the need for accurate long-range tracking has become less important since the ending of the Cold War, and less-expensive ground-based radars are once again being considered for roles such as maritime reconnaissance and drug enforcement.
The AN/FPS-108 COBRA DANE is a PESA phased array radar installation operated by Raytheon for the United States Space Force at Eareckson Air Station on the island of Shemya, Aleutian Islands, Alaska. The system was built in 1976 and brought online in 1977 for the primary mission of gathering intelligence about Russia's ICBM program in support of verification of the SALT II arms limitation treaty. Its single face 29 m (95 ft) diameter phased array radar antenna 52.7373°N 174.0914°E faces the Kamchatka Peninsula and Russia's Kura Test Range. COBRA DANE operates in the 1215–1400 MHz band.
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-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.
The AN/FPQ-6 is a fixed, land-based C-band radar system used for long-range, small-target tracking. The AN/FPQ-6 Instrumentation Radar located at the NASA Kennedy Space Center was the principal C-Band tracking radar system for Apollo program.
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 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.
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.
Eglin AFB Site C-6 is a United States Space Force radar station which houses the AN/FPS-85 phased array radar, associated computer processing system(s), and radar control equipment. Commencing operations in 1969, the AN/FPS-85 was the first large phased array radar. The entire radar/computer system is located at a receiver/transmitter building and is supported by the site's power plant, fire station, 2 water wells, and other infrastructure for the system. As part of the US Space Force's Space Surveillance Network its mission is to detect and track spacecraft and other manmade objects in Earth orbit for the Combined Space Operations Center satellite catalogue. With a peak radiated power of 32 megawatts the Space Force claims it is the most powerful radar in the world, and can track a basketball-sized object up to 22,000 nautical miles (41,000 km) from Earth.
