The AN/FPS-133 Air Force Space Surveillance System, colloquially known as the Space Fence, was a U.S. government multistatic radar system built to detect orbital objects passing over America. It is a component of the US space surveillance network, and according to the US Navy was able to detect basketball sized objects at heights up to 30,000 km
Automatic gain control (AGC), is a closed-loop feedback regulating circuit in an amplifier or chain of amplifiers, the purpose of which is to maintain a suitable signal amplitude at its output, despite variation of the signal amplitude at the input. The average or peak output signal level is used to dynamically adjust the gain of the amplifiers, enabling the circuit to work satisfactorily with a greater range of input signal levels. It is used in most radio receivers to equalize the average volume (loudness) of different radio stations due to differences in received signal strength, as well as variations in a single station's radio signal due to fading. Without AGC the sound emitted from an AM radio receiver would vary to an extreme extent from a weak to a strong signal; the AGC effectively reduces the volume if the signal is strong and raises it when it is weaker. In a typical receiver the AGC feedback control signal is usually taken from the detector stage and applied to control the gain of the IF or RF amplifier stages.
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 Raytheon MIM-23 Hawk is an American medium-range surface-to-air missile. It was designed to be a much more mobile counterpart to the MIM-14 Nike Hercules, trading off range and altitude capability for a much smaller size and weight. Its low-level performance was greatly improved over Nike through the adoption of new radars and a continuous wave semi-active radar homing guidance system.
The AGM-124 Wasp is a missile developed by the United States. The Wasp grew out of the 1975 WAAM program initiated by the US Air Force in order to develop a series of new air-to-ground anti-armour weapons for close-support aircraft. The three-pronged program led to the CBU-92/B ERAM, the CBU-90/B ACM, and the Wasp anti-armour missile. The Wasp is regarded as the most advanced of these weapons.
An airport surveillance radar (ASR) is a radar system used at airports to detect and display the presence and position of aircraft in the terminal area, the airspace around airports. It is the main air traffic control system for the airspace around airports. At large airports it typically controls traffic within a radius of 60 miles (96 km) of the airport below an elevation of 25,000 feet. The sophisticated systems at large airports consist of two different radar systems, the primary and secondary surveillance radar. The primary radar typically consists of a large rotating parabolic antenna dish that sweeps a vertical fan-shaped beam of microwaves around the airspace surrounding the airport. It detects the position and range of aircraft by microwaves reflected back to the antenna from the aircraft's surface. In the US the primary radar operates at a frequency of 2.7 - 2.9 GHz in the S band with a peak radiated power of 25 kW and an average power of 2.1 kW. The secondary surveillance radar consists of a second rotating antenna, often mounted on the primary antenna, which interrogates the transponders of aircraft, which transmits a radio signal back containing the aircraft's identification, barometric altitude, and an emergency status code, which is displayed on the radar screen next to the return from the primary radar. It operates at a frequency of 1.03 - 1.09 GHz in the L band with peak power of 160 - 1500 W.
The Space Fence is a second-generation space surveillance system currently being built by the US Air Force in order to track artificial satellites and space debris in Earth orbit.
A radar system has look-down/shoot-down capability if it can detect, track and guide a weapon to an air target moving below the horizon as seen by the radar.
A radar system uses a radio frequency electromagnetic signal reflected from a target to determine information about that target. In any radar system, the signal transmitted and received will exhibit many of the characteristics described below.
Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to radars. Such echoes are typically returned from ground, sea, rain, animals/insects, chaff and atmospheric turbulences, and can cause serious performance issues with radar systems.
Radar MASINT is a subdiscipline of measurement and signature intelligence (MASINT) and refers to intelligence gathering activities that bring together disparate elements that do not fit within the definitions of signals intelligence (SIGINT), imagery intelligence (IMINT), or human intelligence (HUMINT).
Moving target indication (MTI) is a mode of operation of a radar to discriminate a target against the clutter. It describes a variety of techniques used to find moving objects, like an aircraft, and filter out unmoving ones, like hills or trees. It contrasts with the modern stationary target indication (STI) technique, which uses details of the signal to directly determine the mechanical properties of the reflecting objects and thereby find targets whether they are moving or not.
Stationary target indication (STI) is a mode of operation for radar that enables the operator to discriminate between a target and clutter.
The General Dynamics MIM-46 Mauler was a self-propelled anti-aircraft missile system designed to a late 1950s US Army requirement for a system to combat low-flying high-performance tactical fighters and short-range ballistic missiles. Based on the M113 chassis, Mauler carried search and attack radars, fire control computers and nine missiles in a highly mobile platform. An ambitious design for its era, the Mauler ran into intractable problems during development, and was eventually canceled in November 1965.
The "Pegmantit 8" or P-8 was an early 2D VHF radar developed and operated by the former Soviet Union.
The "Pegmantit 10" or P-10 was an early 2D VHF radar developed and operated by the former Soviet Union.
Marine radars are X band or S band radars on ships, used to detect other ships and land obstacles, to provide bearing and distance for collision avoidance and navigation at sea. They are electronic navigation instruments that use a rotating antenna to sweep a narrow beam of microwaves around the water surface surrounding the ship to the horizon, detecting targets by microwaves reflected from them, generating a picture of the ship's surroundings on a display screen. A Radar has a flat antenna that spins, emitting a signal, then listening back for that signal. The return signal bounces back at varying times based on what it may be bouncing off of.
The radar horizon is a critical area of performance for aircraft detection systems that is defined by the distance at which the radar beam rises enough above the Earth's surface to make detection of a target at low level impossible. It is associated with the low elevation region of performance, and its geometry depends on terrain, radar height, and signal processing. This is associated with the notions of radar shadow, the clutter zone, and the clear zone.
United States general surveillance radar stations include Army and USAF stations of various US air defense networks :
