Radar is a radiolocation system that uses radio waves to determine the distance (ranging), angle (azimuth), and radial velocity of objects relative to the site. It is used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna and a receiver and processor to determine properties of the objects. Radio waves from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds.
An airborne early warning and control (AEW&C) system is an airborne radar early warning system designed to detect aircraft, ships, vehicles, missiles and other incoming projectiles at long ranges, as well as performing command and control of the battlespace in aerial engagements by informing and directing friendly fighter and attack aircraft. AEW&C units are also used to carry out aerial surveillance over ground and maritime targets, and frequently perform battle management command and control (BMC2). When used at altitude, the radar system on AEW&C aircraft allows the operators to detect, track and prioritize targets and identify friendly aircraft from hostile ones at real-time and from much farther away than ground-based radars. Like a ground-based radars, AEW&C systems can be detected and targeted by opposing forces, but due to aircraft mobility and extended sensor range, they are much less vulnerable to counter-attacks that ground systems.
The Euroradar Captor is a next-generation mechanical multi-mode pulse Doppler radar designed for the Eurofighter Typhoon. Development of Captor led to the Airborne Multirole Solid State Active Array Radar (AMSAR) project which eventually produced the CAESAR, now known as Captor-E.
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).
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beamforming can be used at both the transmitting and receiving ends in order to achieve spatial selectivity. The improvement compared with omnidirectional reception/transmission is known as the directivity of the array.
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.
Electronic counter-countermeasures (ECCM) is a part of electronic warfare which includes a variety of practices which attempt to reduce or eliminate the effect of electronic countermeasures (ECM) on electronic sensors aboard vehicles, ships and aircraft and weapons such as missiles. ECCM is also known as electronic protective measures (EPM), chiefly in Europe. In practice, EPM often means resistance to jamming. A more detailed description defines it as the electronic warfare operations taken by a radar to offset the enemy's countermeasure.
Passive radar is a class of radar systems that detect and track objects by processing reflections from non-cooperative sources of illumination in the environment, such as commercial broadcast and communications signals. It is a specific case of bistatic radar – passive bistatic radar (PBR) – which is a broad type also including the exploitation of cooperative and non-cooperative radar transmitters.
Inverse synthetic-aperture radar (ISAR) is a radar technique using radar imaging to generate a two-dimensional high resolution image of a target. It is analogous to conventional SAR, except that ISAR technology uses the movement of the target rather than the emitter to create the synthetic aperture. ISAR radars have a significant role aboard maritime patrol aircraft to provide them with radar image of sufficient quality to allow it to be used for target recognition purposes. In situations where other radars display only a single unidentifiable bright moving pixel, the ISAR image is often adequate to discriminate between various missiles, military aircraft, and civilian aircraft.
The AN/APG-66 radar is a solid state medium range pulse-Doppler planar array radar originally designed by the Westinghouse Electric Corporation for use in early generations of the F-16 Fighting Falcon. This radar was employed in all domestic and export versions of the F-16 A/B models throughout the production. Subsequent upgrades have been installed in many varying aircraft types, including the U.S. Customs and Border Protection's C-550 Cessna Citation, US Navy P-3 Orion, and Piper PA-42 Cheyenne II's, as well as the Small Aerostat Surveillance System (SASS). Primary air-combat mode is look-down. In that mode, the AN/APG-66 can detect a fighter-size plane at a range of 34.5 Nautical miles. Four modes are available in air-to-air combat. In dogfight mode, the radar scans a 20 degrees x 20 degrees field. In high-g maneuvers, it scans a 40 degrees x10 degrees pattern. The radar system consists of the following line-replaceable units:
The SLC-2 Radar is a Chinese active electronically scanned array counter-battery radar designed to locate hostile artillery, rocket and ground-to-ground missile launchers immediately after firing, and to support friendly artillery by guiding counter-battery fire.
YLC-4 is a Chinese UHF solid-state, fully coherent 2D long range surveillance radar, which is mainly used for long range surveillance. The radar has the ability to synthesize data from up to four other radars with a large data capacity, and to communicate and display the data and state of the system through the net to realize remote control and detection. When equipped with height-finding radar, it can perform the function of guidance and providing target data for an air traffic control system. With long range detection range, high reliability and easy maintenance, YLC-4 radar is a main radar in air defense network. The manufacturer of the system is Nanjing Research Institute of Electronics Technology (NRIET)/Nanjing Institute No. 1 /南京电子技术研究所.
YLC-6 is a series of two-dimensional radars from Nanjing Research Institute of Electronics Technology (NRIET) for mobile and static medium- and low-altitude surveillance.
YLC-15 is a fully coherent, Pulse Doppler air defence radar of Chinese origin. It is designed primarily to detect targets at ranges of up to 16 km. It also provides the capability to identify hovering helicopters or low altitude cruise missiles.
The Bars (Leopard) is a family of Russian all-weather multimode airborne radars developed by the Tikhomirov Scientific Research Institute of Instrument Design for multi-role combat aircraft such as the Su-27, Su-30 and the MiG-29.
Electronics and Radar Development Establishment (LRDE) is a laboratory of the Defence Research & Development Organisation (DRDO), India. Located in C.V. Raman Nagar, Bengaluru, Karnataka, its primary function is research and development of radars and related technologies. It was founded by S. P. Chakravarti, the father of Electronics and Telecommunication engineering in India, who also founded DLRL and DRDL.
Track-while-scan (TWS) is a mode of radar operation in which the radar allocates part of its power to tracking a target or targets while part of its power is allocated to scanning. It is similar to but functions differently in comparison to its counterparts range-while-search (RWS), long range search (LRS), air combat mode (ACM), velocity search with ranging (VSR) and combined radar mode (CRM). In track-while-scan mode the radar has the ability to acquire and lock/track multiple targets while simultaneously providing a view of the surrounding airspace, which in turn aids the pilot and or operator in maintaining better situational awareness.
Irbis-E is a Russian multi-mode, hybrid passive electronically scanned array radar system developed by Tikhomirov NIIP for the Sukhoi Su-35 multi-purpose fighter aircraft. NIIP developed the Irbis-E radar from the N011M Bars radar system used on Sukhoi Su-30MKI aircraft.
The chirp pulse compression process transforms a long duration frequency-coded pulse into a narrow pulse of greatly increased amplitude. It is a technique used in radar and sonar systems because it is a method whereby a narrow pulse with high peak power can be derived from a long duration pulse with low peak power. Furthermore, the process offers good range resolution because the half-power beam width of the compressed pulse is consistent with the system bandwidth.
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.
