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.
Signals intelligence (SIGINT) is the act and field of intelligence-gathering by interception of signals, whether communications between people or from electronic signals not directly used in communication. As classified and sensitive information is usually encrypted, signals intelligence may necessarily involve cryptanalysis. Traffic analysis—the study of who is signaling to whom and in what quantity—is also used to integrate information, and it may complement cryptanalysis.
A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. This variation gives direct and highly accurate measurements of the radial component of a target's velocity relative to the radar. The term applies to radar systems in many domains like aviation, police radar detectors, navigation, meteorology, etc.
Electromagnetic warfare or electronic warfare (EW) is warfare involving the use of the electromagnetic spectrum or directed energy to control the spectrum, attack an enemy, or impede enemy operations. The purpose of electromagnetic warfare is to deny the opponent the advantage of—and ensure friendly unimpeded access to—the EM spectrum. Electromagnetic warfare can be applied from air, sea, land, or space by crewed and uncrewed systems, and can target communication, radar, or other military and civilian assets.
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.
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).
An electronic countermeasure (ECM) is an electrical or electronic device designed to trick or deceive radar, sonar, or other detection systems, like infrared (IR) or lasers. It may be used both offensively and defensively to deny targeting information to an enemy. The system may make many separate targets appear to the enemy, or make the real target appear to disappear or move about randomly. It is used effectively to protect aircraft from guided missiles. Most air forces use ECM to protect their aircraft from attack. It has also been deployed by military ships and recently on some advanced tanks to fool laser/IR guided missiles. It is frequently coupled with stealth advances so that the ECM systems have an easier job. Offensive ECM often takes the form of jamming. Self-protecting (defensive) ECM includes using blip enhancement and jamming of missile terminal homers.
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.
Continuous-wave radar is a type of radar system where a known stable frequency continuous wave radio energy is transmitted and then received from any reflecting objects. Individual objects can be detected using the Doppler effect, which causes the received signal to have a different frequency from the transmitted signal, allowing it to be detected by filtering out the transmitted frequency.
A low-probability-of-intercept radar (LPIR) is a radar employing measures to avoid detection by passive radar detection equipment while it is searching for a target or engaged in target tracking. This characteristic is desirable in a radar because it allows finding and tracking an opponent without alerting them to the radar's presence. This also protects the radar installation from anti-radiation missiles (ARMs).
The AN/MPQ-64 Sentinel is an X-band electronically steered pulse-Doppler 3D radar system used to alert and cue Short Range Air Defense (SHORAD) weapons to the locations of hostile targets approaching their front line forces. It is currently produced by Raytheon Missiles & Defense.
Radar jamming and deception is a form of electronic countermeasures (ECMs) that intentionally sends out radio frequency signals to interfere with the operation of radar by saturating its receiver with noise or false information. Concepts that blanket the radar with signals so its display cannot be read are normally known as jamming, while systems that produce confusing or contradictory signals are known as deception, but it is also common for all such systems to be referred to as jamming.
An infrared countermeasure (IRCM) is a device designed to protect aircraft from infrared homing missiles by confusing the missiles' infrared guidance system so that they miss their target. Heat-seeking missiles were responsible for about 80% of air losses in Operation Desert Storm. The most common method of infrared countermeasure is deploying flares, as the heat produced by the flares creates hundreds of targets for the missile.
The JY-14 is a medium to long range air defense radar produced and used by the People's Republic of China. It is capable of detecting multiple targets within its range and determine their parameters, tracking them even through surface clutter and ECM jamming. It utilizes a frequency-agile mode with 31 different frequencies, has a large band of ECCM operating parameter frequencies, and uses linear FM compression. This system can simultaneously track up to 100 targets and can feed the data to missile-interceptor batteries. It can track targets flying as high as 75,000 feet (22,900 m) and 186 miles (299 km) in distance.
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.
The Combat Aircraft Systems Development & Integration Centre (CASDIC) is a laboratory of the Indian Defence Research and Development Organisation (DRDO). Located in Bangalore, Karnataka, India, It is one of the two DRDO laboratories involved in the research and development of airborne electronic warfare and mission avionics systems.
The Radio Research Laboratory (RRL), located on the campus of Harvard University, was an 800-person secret research laboratory during World War II. Under the U.S. Office of Scientific Research and Development (OSRD), it was a spinoff of the Radiation Laboratory at MIT and set up to develop electronic countermeasures to enemy radars and communications, as well as electronic counter-countermeasures (ECCM) to circumvent enemy ECM. The RRL was directed by Frederick E. Terman and operated between 1942 and 1946.
The EuroDASS Praetorian DASS is an integral part of Eurofighter Typhoon defensive Aid Sub-System (DASS) providing threat assessment, aircraft protection and support measures in extremely hostile and severe environments. As the DASS is fully integrated, it does not require additional pods that take up weapon stations or would influence the aircraft's aerodynamic performance. The modular nature of the DASS simplifies future upgrades and allows each partner nation or export customer the option to tailor the DASS to their individual needs.
An inverse monopulse seeker is a type of semi-active radar homing that offers significant advantages over earlier designs. The system requires electronics that can compare three signals at once, so this design did not become practically possible until the early 1970s. One of the first such examples was the Soviet Union R-40 air-to-air missiles used in MiG-25P introduced in service in 1970 and RAF's Skyflash missile introduced in 1978, an adaptation of the AIM-7 Sparrow that replaced the original Raytheon seeker with a monopulse model from Marconi, followed by a very similar conversion by Selenia for the Italian Aspide. The USAF adopted similar technology in the M model of the AIM-7 Sparrow, and such designs are universal in semi-active designs today.
The AR-320 is a 3D early warning radar developed by the UK's Plessey in partnership with US-based ITT-Gilfillan. The system combined the receiver electronics, computer systems and displays of the earlier Plessey AR-3D with a Gilfillan-developed transmitter and planar array antenna from their S320 series. The main advantage over the AR-3D was the ability to shift frequencies to provide a level of frequency agility and thus improve its resistance to jamming.
