AWG-9 and APG-71 radars
Encyclopedia
F-14 Tomcat
The Grumman F-14 Tomcat is a supersonic, twin-engine, two-seat, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental program following the collapse of the F-111B project...
. It is a very long-range air-to-air system with the capability of guiding several AIM-54 Phoenix
AIM-54 Phoenix
The AIM-54 Phoenix is a radar-guided, long-range air-to-air missile , carried in clusters of up to six missiles on F-14 Tomcats, its only launch platform. The Phoenix was the United States' only long-range air-to-air missile. The weapons system based on Phoenix was the world's first to allow...
or AIM-120 AMRAAM
AIM-120 AMRAAM
The AIM-120 Advanced Medium-Range Air-to-Air Missile, or AMRAAM , is a modern beyond-visual-range air-to-air missile capable of all-weather day-and-night operations. Designed with the same form-factor as the previous generation of semi-active guided Sparrow missiles, it is a fire-and-forget...
missiles at the same time using its track while scan
Track while scan
The track while scan is a mode of radar operation in which the radar allocates part of its power to tracking the target or targets while part of its power is allocated to scanning, unlike the straight tracking mode, when the radar directs all its power to tracking the acquired targets...
mode. The primary difference between the AWG-9 and APG-71 is the replacement of the former's analog electronics with all-digital units. Both the AWG-9 and APG-71 were designed and manufactured by Hughes Aircraft
Hughes Aircraft
Hughes Aircraft Company was a major American aerospace and defense contractor founded in 1932 by Howard Hughes in Culver City, California as a division of Hughes Tool Company...
; contractor support is now being provided by Raytheon
Raytheon
Raytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...
.
The AN/AWG-9 offers a variety of air-to-air modes including long-range continuous wave velocity search, range-while-search at shorter ranges, and the first use of an airborne track-while-scan mode with the ability to track up to 24 airborne targets, display 18 of them on the cockpit displays, and launch against 6 of them at the same time. This function was originally designed to allow the Tomcat to shoot down formations of bombers at long range.
AN/AWG-9
The AWG-9 was the result of a series of Navy programs to build what was known as a "fleet-defense fighter"; an aircraft armed with extremely long-range radars and missiles that would be able to engage formations of enemy aircraft well-away from aircraft carrierAircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
s. Their first attempt was the F6D Missileer
F6D Missileer
The Douglas F6D Missileer was a proposed carrier-based US Navy fleet defense fighter aircraft, designed by Douglas Aircraft Company in response to a 1959 US Navy requirement...
, which combined Westinghouse's AN/APQ-81 pulse doppler radar with the Bendix
Bendix
- People :* Bendix Hallenstein - New Zealand businessman* Henry Bendix - fictional character from Wildstorm comics* John E. Bendix - American Civil War and New York Guard general* Max Bendix - American composer, conductor, violinist* Reinhard Bendix - sociologist...
AAM-N-10 Eagle missile. The Missileer was a relatively simple aircraft, and when planners expressed doubts about its ability to survive after firing its missiles, the Missileer was canceled and the Navy started looking for higher-performance alternatives.
At the same time, the U.S Air Force had been working on a similar long-range interceptor project of their own, the XF-108 Rapier
XF-108 Rapier
The North American XF-108 Rapier was a proposed long-range, high-speed interceptor aircraft designed by North American Aviation. Initiated to defend the United States from supersonic Soviet bombers, the program, initially called NA-257, was cancelled in 1959 due to a shortage of funds and the...
. The Rapier had much better performance than the Missileer, although its AIM-47 Falcon
AIM-47 Falcon
The Hughes AIM-47 Falcon, originally GAR-9, was a very long-range high-performance air-to-air missile that shared the basic design of the earlier AIM-4 Falcon. It was developed in 1958 along with the new Hughes AN/ASG-18 radar fire-control system intended to arm the Mach 3 XF-108 Rapier interceptor...
and AN/ASG-18 radar, both from Hughes, were somewhat less advanced than their Navy counterparts. The entire system was also very expensive, and the Rapier was canceled, replaced by the hopefully less-expensive Lockheed YF-12
Lockheed YF-12
The Lockheed YF-12 was an American prototype interceptor aircraft, which the United States Air Force evaluated as a development of the highly-secret Lockheed A-12 that also spawned the SR-71 Blackbird.-Design and development:...
adapted from the Lockheed A-12 spy plane. This project was also canceled as the strategic threat moved from bombers to ICBM's.
The same was not true for the Navy, where the threat remained manned aircraft and early anti-ship missile
Anti-ship missile
Anti-ship missiles are guided missiles that are designed for use against ships and large boats. Most anti-ship missiles are of the sea-skimming type, many use a combination of inertial guidance and radar homing...
s. Hughes suggested that the AN/ASG-18 and AIM-47 could be adapted for the Navy in slightly-modified form, adding additional tracking capability while reducing the size of the radar antenna to a size more suitable for carrier aircraft. The result was the AN/AWG-9 radar and Phoenix missile.
All that was needed was a suitable airframe, which led to the Navy's involvement in the F-111B program. Although the radar and missile systems started to mature (after the better part of a decade at this point) the F-111B proved to be considerably overweight and had marginal performance, especially in engine-out situations. At the same time, real-world combat over Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
was proving that the idea of the all-missile fighter was simply not viable, and any fighter design would have to be able to dogfight
Dogfight
A dogfight, or dog fight, is a form of aerial combat between fighter aircraft; in particular, combat of maneuver at short range, where each side is aware of the other's presence. Dogfighting first appeared during World War I, shortly after the invention of the airplane...
with guns, which the F-111 was simply not suited to. This should not be surprising given the F-111's genesis as a tactical bomber
Tactical bomber
A tactical bomber is a bomber aircraft with an intended primary role of tactical bombing—attacking tactical targets, such as enemy's troops and military equipment. This implies that either aircraft's range or ordnance is insufficient to use it effectively as a strategic bomber.All light bombers,...
and interdictor
Interdictor
An interdictor is a type of ground-attack aircraft that operates far behind enemy lines, with the express intent of interdicting the enemy's military targets, most notably those involved in logistics. The term has generally fallen from use...
.
After many years in development and arguing with Congress, the Navy finally started development of a new aircraft specifically tailored to their needs. The new aircraft emerged as the F-14, armed with the same AWG-9/AIM-47 outfit originally intended for the F-111B. On the F-14, the AWG-9 is capable of detecting bomber-sized targets at ranges exceeding 100 miles (160 km), and its doppler system allows it to have look-down, shoot-down capabilities. Track-while-scan capability is provided by an Intel 8080
Intel 8080
The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
8-bit microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
; programming it is accomplished using an 8-bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
Assembly
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
code.
Hughes delivered enough AWG-9 systems and spares to equip approximately 600 F-14A/B aircraft for the Navy, and an additional 78 aircraft for the Iranian Air Force. All of the Navy systems have been retired; the status of the Iranian systems is unknown, but it is believed that they are still in service.
AN/APG-71
The APG-71 was a 1980s upgrade of the AWG-9 for use on the F-14D. It incorporates technology and common modules developed for the APG-70APG-63 and APG-70 radars
The AN/APG-63 and AN/APG-70 are a family of all-weather multimode radar systems designed by Hughes Aircraft for the F-15 Eagle air superiority fighter. These X-band pulse-doppler radar systems are designed for both air-air and air-ground missions; they are able to look up at high-flying targets...
radar used in the F-15E Strike Eagle
F-15E Strike Eagle
The McDonnell Douglas F-15E Strike Eagle is an all-weather multirole fighter, derived from the McDonnell Douglas F-15 Eagle. The F-15E was designed in the 1980s for long-range, high speed interdiction without relying on escort or electronic warfare aircraft. United States Air Force F-15E Strike...
, providing significant improvements in (digital) processing speed, mode flexibility, clutter rejection, and detection range. The system features a low-sidelobe antenna, a sidelobe-blanking guard channel, and monopulse angle tracking; all of which are intended to make the radar less vulnerable to jamming.
The system itself is capable of a 460 mile (740 km) range, but the antenna design limits this to only 230 miles (370 km). Use of datalinked data allows two or more F-14D's to operate the system at its maximum range.
Hughes delivered enough APG-71 radars and spares to equip 55 F-14Ds before the program was scaled back as a cost-cutting measure and eventually canceled. The F-14 was officially retired from United States Navy service on September 22, 2006, with the last flight occurring October 4, 2006. The last navy squadron utilizing the F-14 was (VF-31
VF-31
VFA-31 or Strike Fighter Squadron 31 is known as the Tomcatters, callsign "Felix", a United States Navy strike fighter squadron stationed at Naval Air Station Oceana flying the F/A-18E Super Hornet.-Squadron insignia and nickname:...
).