Typically fitted to
military aircraftA military aircraft is any fixed-wing or rotary-wing aircraft that is in the current employ of a military power. Fixed-wing military aircraft are also known as Warplanes....
,
radar warning receivers (RWR) detect the
radioRadio is the transmission of signals by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
emissions of
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
systems, whether ground-based or on-board other aircraft. The system is often capable of classifying the source of the radar by type (
Pulsed powerPulsed power is the term used to describe the science and technology of accumulating energy over a relatively long period of time and releasing it very quickly thus increasing the instantaneous power.-Overview:...
or
continuous waveA continuous wave or continuous waveform is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off. Information...
radar, for example) and strength. It may be further capable of using this data to identify the type of threat the detected radar poses, for example an incoming radar-guided
surface-to-air missileA Surface to Air Missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft. It is a type of anti-aircraft system....
(SAM).
The RWR usually has a visual display somewhere prominent in the cockpit (in some modern aircraft, in multiple locations in the cockpit) and also generates audible tones which feed into the pilot's (and perhaps RIO/co-pilot/GIB's in a multi-seat aircraft) headset.
Typically fitted to
military aircraftA military aircraft is any fixed-wing or rotary-wing aircraft that is in the current employ of a military power. Fixed-wing military aircraft are also known as Warplanes....
,
radar warning receivers (RWR) detect the
radioRadio is the transmission of signals by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
emissions of
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
systems, whether ground-based or on-board other aircraft. The system is often capable of classifying the source of the radar by type (
Pulsed powerPulsed power is the term used to describe the science and technology of accumulating energy over a relatively long period of time and releasing it very quickly thus increasing the instantaneous power.-Overview:...
or
continuous waveA continuous wave or continuous waveform is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off. Information...
radar, for example) and strength. It may be further capable of using this data to identify the type of threat the detected radar poses, for example an incoming radar-guided
surface-to-air missileA Surface to Air Missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft. It is a type of anti-aircraft system....
(SAM).
Description
The RWR usually has a visual display somewhere prominent in the cockpit (in some modern aircraft, in multiple locations in the cockpit) and also generates audible tones which feed into the pilot's (and perhaps RIO/co-pilot/GIB's in a multi-seat aircraft) headset. The visual display often takes the form of a circle, with symbols displaying the detected radars according to their direction relative to the current aircraft heading (i.e. a radar straight ahead displayed at the top of the circle, directly behind at the bottom, etc.). The distance from the center of the circle, depending on the type of unit, can represent the estimated distance from the generating radar, or to categorize the severity of threats to the aircraft, with tracking radars placed closer to the center than search radars. The symbol itself is related to the type of
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
or the type of vehicle that carries it, often with a distinction made between ground-based radars and airborne radars. Audible tones are usually assigned to each type of threat or type of
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
and are fairly distinctive. The more serious the threat, the more shrill the tone. For example, an active missile seeker might be a high pitched, almost continuous trill, whereas the
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
of an obsolete fighter type or SAM system might be a low pitched, intermittent buzz.
The RWR is used for identifying, avoiding, evading or engaging threats. For example, a
fighter aircraftA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
on a
combat air patrolCombat air patrol is a type of flying mission for fighter aircraft.A combat air patrol is an aircraft patrol provided over an objective area, over the force protected, over the critical area of a combat zone, or over an air defense area, for the purpose of intercepting and destroying hostile...
(
CAPA cap is a form of headgear.Cap may also refer to:* Bottle cap, a closure to seal bottles* Screw cap, a closure to seal bottles or jars* Cap , a statistic representing an athlete's appearance in a select team game...
) might notice enemy fighters on the RWR and subsequently use its own
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
set to find and eventually engage the bandit. In addition, the RWR helps identify and classify threats — it's hard to tell which blips on a
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
are dangerous, but since different
fighter aircraftA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
typically have different types of
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
sets, once they turn them on and point them near the aircraft in question it may be able to tell, by the direction and strength of the signal, which of the blips is which type of fighter.
A non-combat
aircraftAn aircraft is a vehicle which is able to fly by being supported by the air, or in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil An aircraft is a vehicle which is able to fly by being supported...
, or one attempting to avoid engagements, might turn its own
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
off and attempt to steer around threats detected on the RWR. Especially at high altitude (more than 30,000 feet
AGLIn aviation and atmospheric sciences, an altitude is said to be above ground level when it is measured with respect to the underlying ground surface. This is as opposed to above mean sea level , or in broadcast engineering, height above average terrain...
), very few threats exist that don't emit radiation. As long as the pilot is careful to check for aircraft that might try to sneak up without radar, say with the assistance of AWACS or
GCIGround-controlled interception an air defense tactic whereby one or more radar stations are linked to a command communications center guides interceptor aircraft to an airborne target. This tactic was pioneered by the Royal Air Force during the World War II, although the Luftwaffe eventually built...
, it should be able to steer clear of SAMs,
fighter aircraftA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
and high altitude, radar-directed AAA.
SEADSEAD , or Suppression of Enemy Air Defenses, also known as "Wild Weasels" and "Iron Hand" operations in the USA, are military actions to suppress enemy surface-based air defenses , primarily in, but not limited to, the first hours of an attack.One fourth of American combat sorties in...
and ELINT aircraft often have sensitive and sophisticated RWR equipment like the U.S. HTS (
HARMThe AGM-88 High-speed Anti-Radiation Missile is a tactical, air-to-surface missile designed to home in on electronic transmissions coming from surface-to-air radar systems. It was originally developed by Texas Instruments as a replacement for the AGM-45 Shrike and AGM-78 Standard ARM system...
targeting system) pod which is able to find and classify threats which are much further away than those detected by a typical RWR, and may be able to overlay threat circles on a map in the aircraft's
multi-function displayA Multi-function display is a small screen in an aircraft surrounded by multiple buttons that can be used to display information to the pilot in numerous configurable ways. Often an MFD will be used in concert with a Primary Flight Display. MFDs are part of the digital era of modern planes or...
(
MFDMFD may refer to:* Madison Fire Department* Mansfield Lahm Regional Airport, IATA Code: MFD* Microfarad, or one millionth of a farad* Mladá fronta DNES, a daily newspaper in the Czech Republic...
), providing much better information for avoiding or engaging threats, and may even store information to be analyzed later or transmitted to the ground to help the commanders plan future missions.
The RWR can be an important tool for evading threats if avoidance has failed. For example, if a SAM system or enemy
fighter aircraftA fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets by dropping bombs. Fighters are small, fast, and maneuverable...
has fired a
missileA missile is a self-propelled projectile used as a weapon. Missiles are typically propelled by rockets or jet engines. Missiles generally have one or more explosive warheads, although other weapon types may also be used...
(for example, a
SARHSarh is the third largest city in Chad, after N'Djamena and Moundou. It is the capital of Moyen-Chari region and the department of Barh Köh. It lies 350 miles south-east of the capital Ndjamena on the Chari River....
-guided
missileA missile is a self-propelled projectile used as a weapon. Missiles are typically propelled by rockets or jet engines. Missiles generally have one or more explosive warheads, although other weapon types may also be used...
) at the aircraft, the RWR may be able to detect the change in mode that the
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
must use to guide the missile and notify the pilot with much more insistent warning tones and flashing, bracketed symbols on the RWR display. The pilot then knows to take evasive action, and what type of evasive action to take to break the
missile lock-onMissile lock-on refers to a scenario where the guidance system for a missile can accurately track a target, and a fire-control system can calculate the required flightpath for the missile to hit the target...
or dodge the
missileA missile is a self-propelled projectile used as a weapon. Missiles are typically propelled by rockets or jet engines. Missiles generally have one or more explosive warheads, although other weapon types may also be used...
. The pilot may even be able to visually acquire the missile after being alerted to the possible launch. What's more, if an actively guided missile is tracking the aircraft, the pilot can use the direction and distance display of the RWR to work out which evasive maneuvers to perform to outrun or dodge the missile. For example, the rate of closure and aspect of the incoming missile may allow the pilot to determine that if they dive away from the missile, it is unlikely to catch up, or if it is closing fast, that it is time to jettison external supplies and turn toward the missile in an attempt to out-turn it.
RWR types in service
- AN/ALR-46 (F-4 Phantom II
The McDonnell Douglas F-4 Phantom II is a tandem two-seat, twin-engined, all-weather, long-range supersonic jet interceptor fighter/fighter-bomber originally developed for the U.S. Navy by McDonnell Aircraft. Proving highly adaptable, it became a major part of the air wings of the United States...
, RF-4 Phantom II, F-5The Northrop F-5A/B Freedom Fighter and F-5E/F Tiger II are part of a family of widely used light supersonic fighter aircraft, designed and built by Northrop in the United States, beginning in 1960s...
)
- AN/ALR-56 (USA; F-15 Eagle, Canada; CC-130 Hercules)
- AN/ALR-66 (USA; P-3C
The Lockheed P-3 Orion is a maritime patrol aircraft used by numerous navies and air forces around the world, primarily for maritime patrol, reconnaissance, anti-surface warfare and anti-submarine warfare.-Development:...
Orion)
- AN/ALR-67
The AN/ALR-67 Radar Warning Receiver is designed to warn an aircraft's crew of potentially hostile radar activity. It is an airborne threat warning and countermeasures control system built to be successor to the United States Navy's AN/ALR-45. Northrop Grumman Corporation's Electronic Systems...
(USA; AV-8B Harrier II, F-14 Tomcat, F/A-18E/F Super Hornet, EA-6B Prowler, Canada; CF-18 Hornet)
- AN/ALR-69 (USA; B-52H Stratofortress, lacks Frequency Selective Receiver Capabilities (FSRS) capabilities however, A-10 Thunderbolt II
The A-10 Thunderbolt II is an American single-seat, twin-engine, straight-wing jet aircraft developed by Fairchild-Republic for the United States Air Force to provide close air support of ground forces by attacking tanks, armored vehicles, and other ground targets with a limited air interdiction...
, AC-130 Spectre, F-16 Fighting Falcon, HH-53, MC-130, F-4E Phantom IIThe McDonnell Douglas F-4 Phantom II is a tandem two-seat, twin-engined, all-weather, long-range supersonic jet interceptor fighter/fighter-bomber originally developed for the U.S. Navy by McDonnell Aircraft. Proving highly adaptable, it became a major part of the air wings of the United States...
).
- AN/ALR-76 (USA; S-3
The Lockheed S-3 Viking was a jet aircraft used by the United States Navy to identify, track, and destroy enemy submarines. In the late 1990s, the S-3B's mission focus shifted to surface warfare and aerial refueling. The Viking also provided electronic warfare and surface surveillance capabilities...
, EP-3)
- AN/ALR-94 (USA; F-22
The Lockheed Martin/Boeing F-22 Raptor is a fifth-generation fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals intelligence roles...
)
- AN/APR-39 (USA, AH-1, AH-64 Apache, CH-46 Sea Knight, CH-47 Chinook
The Boeing CH-47 Chinook is a versatile, twin-engine, tandem rotor heavy-lift helicopter. Its top speed of 170 knots was faster than utility and attack helicopters of the 1960s and even many of today. Its primary roles include troop movement, artillery emplacement and battlefield resupply...
, CH-53, EH-60 Black Hawk, KC-130 Hercules, MH-47 ChinookThe Boeing CH-47 Chinook is a versatile, twin-engine, tandem rotor heavy-lift helicopter. Its top speed of 170 knots was faster than utility and attack helicopters of the 1960s and even many of today. Its primary roles include troop movement, artillery emplacement and battlefield resupply...
, MH-60 Black Hawk, OH-58, OV-1 Mohawk, RC-12, RV-1, UH-1 Iroquois, UH-60 Black Hawk, V-22 OspreyThe Bell-Boeing V-22 Osprey is a multi-mission, military, tiltrotor aircraft with both a vertical takeoff and landing and short takeoff and landing capability. It is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop...
)
- ALR-2002
The AN/ALR-2002 Radar Warning Receiver is designed to warn an aircraft's crew of potentially hostile radar activity. British Aerospace Australia was the sole contractor for the AN/ALR-2002 Australian indigenous System...
(Australia; developmental, project being cancelled)
- ALR-400 (Spain; EF-18A/B Hornet, Airbus A400M, C-295, CH-47 Chinook, Cougar, TIGER, NH90, CH-53)
- SPO-15 Beryoza (India; MiG-29 Fulcrum, Russia; Su-27SK Flanker-B, China; J-11
The Shenyang J-11 is an advanced 4th-generation fighter in the People's Liberation Army Air Force. It is a licensed production variant of the Russian Sukhoi Su-27 SK air-superiority fighter aircraft built by Shenyang Aircraft Corporation...
)
- Tarang (India; MiG-27 Flogger, LCA
LCA is a three-letter abbreviation which may represent any of the following:-Technology:* Landing Craft Assault, a British landing craft of the Second World War....
Tejas, Jaguar, Su-30MKIThe Sukhoi Su-30 MKI is a variant of the Sukhoi Su-30 jointly-developed by Russia's Sukhoi Corporation and India's Hindustan Aeronautics Limited for the Indian Air Force...
Flanker)
See also
- Semi-active radar homing
Semi-active radar homing, or 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...
- Monica tail warning radar
Monica was a range-only tail warning radar for bombers, introduced by the RAF in the spring of 1942. It operated at frequencies of around 300 MHz....
- Boozer
Boozer may refer to:* A person who boozes , especially one who drinks to excess* British slang for pub* A device used in Second World War British bomber aircraft to alert the crew that they were being tracked by enemy radarPeople:...
- Serrate radar detector
Serrate was an Allied radar detection and homing device, used in Allied nightfighters to track German night fighters equipped with Lichtenstein during World War II....
- List of World War II electronic warfare equipment
- List of Rainbow Codes