Tuesday, November 27, 2012

AMRAAM: Deploying & Developing America’s Medium-Range Air-Air Missile

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AIM-120C AMRAAM Launch from F-22

Raytheon’s AIM-120 Advanced, Medium-Range Air to Air Missile (AMRAAM) has become the world market leader for medium range air-to-air missiles, and is also beginning to make inroads within land-based defense systems. It was designed with the lessons of Vietnam in mind, and of local air combat exercises like ACEVAL and Red Flag. This DID FOCUS article covers successive generations of AMRAAM missiles, international contracts and key events from 2006 onward, and even some of its emerging competitors.
One of the key lessons learned from Vietnam was that a fighter would be likely to encounter multiple enemies, and would need to launch and guide several missiles at once in order to ensure its survival. This had not been possible with the AIM-7 Sparrow, a “semi-active radar homing” missile that required a constant radar lock on one target. To make matters worse, enemy fighters were capable of launching missiles of their own. Pilots who weren’t free to maneuver after launch would often be forced to “break lock,” or be killed – sometimes even by a short-range missile fired during the last phases of their enemy’s approach. Since fighters that could carry radar-guided missiles like the AIM-7 tended to be larger and more expensive, and the Soviets were known to have far more fighters overall, this was not a good trade…

Some MRAAM History, and AMRAAM’s Design Approach

Before 1991, the combat record of all air-air missiles was generally poor – and most of the kills scored in combat belonged to short-range heat-seeking missiles. The USA entered Vietnam expecting that 70% of AIM-7 Sparrow missile shots would result in a kill. The real-world total was 8%, even though the USA faced older MiG 17-21 aircraft, rather than the newest Russian fighters.
That trend began to shift somewhat in the 1980s.The Falklands War had no aircraft on either side that could use medium-range air-air missiles, but Israeli F-15s and F-16s used AWACS and poor Syrian tactics to produce an 88-0 kill ratio in 1982. The F-15s’ medium-range AIM-7F Sparrow missiles performed better in terms of fire:kill ratios than they had in past conflicts, but the vast majority of kills were still made with Sidewinder or Python short-range missiles. Further afield, the Iran-Iraq War saw Iran’s F-14 Tomcats demonstrate good performance with their long-range Phoenix missiles, against Iraqi aircraft that often lacked radar warning receivers, and never saw the missiles coming. A reprise of sorts took place in 1991, when exceptional situational awareness and poor Iraqi tactics allowed US aircraft to score around 80% of their Iraqi air-air kills in 1991 with modernized AIM-7 Sparrow medium-range missiles.
The lessons that had led to the AMRAAM program still applied, however, and the conflicts in Lebanon, Iran, and Iraq demonstrated the potential value of longer-range missiles and some of their enabling technologies. That helped AMRAAM retain its support, despite initial development glitches and rising costs. It still aimed to remove the shortcomings that made the AIM-7 a somewhat dangerous weapon for its own side. The key lay in its new approach to guidance.
AIM-120A cutaway . Bigger picture here
In beyond-visual-range engagements, AMRAAM is guided initially by its inertial reference unit and microcomputer, which point it in the right direction based on instructions from the targeting aircraft or platform. A mid-course target location update can be transmitted directly from the launch radar system to correct that if necessary, an approach that may avoid triggering enemy radar warning receivers. In the final phase of tracking, however, the internal active radar seeker becomes completely independent and guides the missile through its own active lock-on. Most sources place its reported range at about 50 km/30 miles.
F/A-18C, fully loaded. Bigger picture here
When coupled with modern radars, AMRAAM’s guidance approach allows a fighter to launch and control many missiles at once, avoiding a dangerous fixation on one target. Its autonomous guidance capability also provides a pilot with critical range-preserving launch and leave capability, improving survivability and helping to avoid “mutual kill” situations. Even more advanced technologies are emerging that go one step further, and allow secure “hand-off” of a fired AMRAAM to another friendly fighter.
All of these abilities, of course, assume an air environment in which it is possible to use IFF (Identification, Friend or Foe), AWACS (Airborne Warning & Control Systems) aircraft, Link 16/MIDS, etc. to safely distinguish enemy aircraft from friendlies. This has been a problem in past conflicts, resulting in rules of engagement that force the use of visual identification before firing. Obviously, that negates many of the tactical advantages of having beyond-visual-range (BVR) missiles.

Customers & Performance

AMRAAM is a joint U.S. Air Force and Navy program that achieved initial operational capability in 1991, and is still in brisk production over 20 years later. At least 28 other countries have also bought AMRAAM variants, which can be fitted to F-15s, F-16s, the F/A-18 family, F-22sF-35sEADS Eurofighters, and Saab’s JAS-39 Gripen. Germany’s aging F-4 Phantom IIs, the British/German/Italian Panavia consortium’s Tornado aircraft, and Britain’s Harriers can also carry them.
Dassault’s Mirage 2000v5 and later have been advertised at times as having this capability, but confirmation is weak, and the reports may have represented offers to add this capability. Dassault’s 4th generation Rafale aircraft is also listed in some venues as having AMRAAM capability, though Raytheon has never said so, and all Rafales currently operate with MBDA’s MICA missiles instead.
Even so, AMRAAM’s record of sales success has made it the global standard for medium-range AAMs, and the number of beyond visual range kills as a percentage of total air-to-air victories has risen sharply during the “AMRAAM era.”
What does this mean in practice for missile performance?
To date, RAND’s Project Air Force notes that AIM-120 missiles have demonstrated 10 kills in 17 firings, for a 59% kill rate. That’s a significant improvement over the AIM-7’s record, and AIM-120A and AIM-120C missiles split these kills equally. Victims have included an Iraqi MiG-25 and MiG-29, 6 Serbian MiG-29s, a Serbian J-21 Jastreb trainer/light attack jet, and the accidental downing of a US Army UH-60A helicopter. The last of these incidents occurred in 1999.
One caution regarding these figures is that both AMRRAM missiles, and electronics used for electronic countermeasures, have both advanced considerably in the dozen-plus since the missile’s last combat kill. A second set of cautions involves the circumstances of these victories. There are no reports of electronic countermeasures being used by any AMRAAM victim, none of these victims were equipped with beyond visual range weapons of their own, the Iraqi MiGs were fleeing and non-maneuvering, and the Serbian MiGs reportedly had inoperative radars.
These difficulties in assessing true BVRAAM (beyond visual range air-air missile) performance in the modern era are magnified by a corollary fact: None of AMRAAM’s competitors have been able to compile much of a performance record, either. With the end of recurring full-scale Arab wars against Israel, the globe’s top trial venue for full-scale warfare has evaporated, leaving few opportunities to put modern anti-aircraft systems to a real test.

AMRAAM: Upgrades & Derivatives

Subsequent modifications have produced improvements in a number of areas, but the AIM-120D is likely to be the first really large jump in AMRAAM capabilities from version to version. It should be noted, however, that incremental upgrades add up over time. An AIM-120C-6, for instance, is a generation beyond an AIM-120A in terms of its overall capabilities.
  • AIM-120B was first delivered in late 1994, had a number of electronics upgrades, from the guidance section to hardware modules and its processor. Its hardware was also reprogrammable, which is not possible with the AIM-120A.
  • AIM-120C missiles featured a change in shape, with smaller fins that would allow 3 missiles to be carried inside the F-22A Raptor’s stealth-maximizing internal weapons bays. A number of incremental updates brought it to AIM-120C-6 status, including guidance section upgrades, smaller control electronics, a slightly larger rocket motor, an improved warhead, and a target detection upgrade. The AIM-120C-7 is just entering production, with an improved seeker head, greater jamming resistance, and slightly longer range. At present, the AIM-120-C7 is also the most advanced AMRAAM approved for export beyond the USA.
  • US-only AIM-120D missiles will feature the C7 improvements, but the D version reportedly adds a very strong set of upgrades. Pentagon documents confirm the use of smaller system components; with an upgraded radar antenna, receiver & signal processor; GPS-aided mid-course navigation; an improved datalink; and new software algorithms. The new hardware and software is rumored to offer improved jamming resistance, better operation in conjunction with modern AESA radars, and an improved high-angle off-boresight “seeker cone,” in order to give the missile a larger no-escape zone. Less-publicized improvements reportedly include a dual-pulse rocket motor, for up to 50% more range and better near-target maneuvering. At present, the US will not export this missile.

    Other AMRAAM-Related Systems

    CLAWS. Bigger picture here    

    Other AMRAAM variants exist. The most interesting AMRAAM modification is NCADE, an R&D program designed to see if AMRAAMs modified with an AIM-9X Sidewinder’s infrared seeker and a 2nd stage rocket booster could be forward-deployed on fighters, and used to shoot down ballistic missiles during their lift-off phase.
    A parallel set of modifications and enhancements have seen AMRAAM missiles pressed into service in a surface-air missile role. Programs like Norway’s NASAMS, the USMC’s CLAWS (ended in 2006), etc. are often referred to by the umbrella term SLAMRAAM, for Surface Launched AMRAAM. SL-AMRAAM contractors include Raytheon, as well as Kongsberg Defence and Aerospace of Norway, and Boeing.
    The US Marines killed CLAWS in 2006, the same year the US Army’s SLAMRAAM passed its System Critical Design Review. The Army eventually teed up SLAMRAAM for cancellation as well, in January 2011, but the USA has a deployed system to protect the Washington DC area, and exports keep it alive and well. Kongsberg has sold its related Norwegian Advanced Surface-to-Air Missile System (NASAMS) system to Norway, FinlandThe Netherlands, Spain, and the USA. There are rumors that a SLAMRAAM type system has been deployed in Egypt, and such systems have drawn official buying interest from ChileOman, and the UAE. The key to effective deployment is integrating the system, and its accompanying IFCS control system and AN/MPQ-64F1 Improved Sentinel radars, with a country’s wider air defense command and control systems.
    The 3 surface launchers for AMRAAM at present include the 8-missile “universal launcher” which can be mounted on medium trucks, the 5-missile CLAWS for smaller vehicles, and the 6-missile fixed NASAMS. All 3 launcher types provide 360 degree coverage, with a 70 degree off boresight capability – i.e. a 140 degree target acquisition cone. In June 2007, Raytheon announced more SLAMRAAM upgrades via options to add SL-AMRAAM-ER extended range variants (likely via a rocket booster on the missiles), and an AIM-120 variant with an AIM-9X infrared seeker. The latter would allow a mix-and-match combination of radar/infrared SAM sets, similar to the Spyder, VL-MICA, etc. being fielded by international rivals. On which topic…

    AMRAAM’s International Competitors

    AA-12 R-77-RVV AE on MiG-29
    R-77/AA-12 on MiG-29
    (click to view full)
    The AMRAAM’s most prominent global competitors, in declining order of prominence, include:
    Russia’s Vympel R-77, also known as the AA-12 Adder and colloquially called the ‘AMRAAMski’. It is a larger missile with a similar guidance approach, and reportedly offers a slightly longer range, varying from 60-90 km (36-54 miles) depending on assessments of its drag coefficient. It looks a bit like the French MICA missiles, but its “screen door” or “potato masher” tail fins are its most distinguishing characteristic. Comparisons of its maneuverability, electronics, and hence its fire:kill effectiveness ratio remain a matter of speculation in public-domain circles, and there are also reports that the R-77 can be launched and ‘handed off’ to another aircraft. This has tactical implications, as discussed by one DID source:
    “The ‘cobra’ maneuver… where the Flanker pitchers [vertically] to over 100 degrees is not a stunt, it is a missile launch maneuver for a over-the-shoulder launch on a passing head-on target by an IMFIL missile, as briefed to me by the Director of TsAGI. German Zagainov.”
    The R-77 can equip modern SU-30 fighters like the SU-30MK2, modernized SU-27s, and some of the most modern MiG-29/35 offerings as well. There are also reports that India has even fitted the missile to its upgraded MiG-21 ‘Bisons,’ leveraging their new Phazotron Kopyo radars and upgraded avionics.
    There are reports that the coming RVV-MD upgrade may extend the missile’s range to 110 km. A R-77M ramjet version has reportedly been developed with 150+ km range, but confirmation of the ramjet program’s success and status remain sketchy. Firmer reports2 now exist re: Russia’s ongoing development of the Novator K-100-1, which is based on the KS-172 missile instead; it will have a reputed range of 200-400 km.
    Meteor Launched
    Meteor BVRAAM
    MBDA’s Meteor, which also includes Saab in the development group and adds Boeing as its American partner. The Meteor stems from Europe’s different fighter design philosophy and acquisition timing. Their 4th generation fighters were introduced in the 1990s, and feature less stealth than the F-22A or F-35. The Eurofighter, Gripen, and Rafale can be fitted with existing missiles like AMRAAM or MICA, but ultimately the Euro vision was that air supremacy against threats like the SU-30/R-77 combination required a long range (100 km/ 60 miles or more) missile – one with extreme maneuverability and ramjet propulsion that gives it Mach 4 powered flight to the very end of its range, rather than the “burn and coast” approach of most missiles. The Meteor is that missile, and it is currently undergoing testing and evaluation; it’s expected in-service around 2011.
    Initial platforms for the Meteor BVRAAMs will include Saab’s JAS-39 Gripen, EADS/BAE Eurofighter, and Dassault’s Rafale. MBDA has announced that it will be modified in future to fit the F-35’s stealth-enhancing weapon bays, and given its characteristics, it also seems like a natural future upgrade for older planes like Tornados and F/A-18s. Forecast International sees MBDA as Raytheon’s biggest overall air-air missile competitor in the coming years.
    MICA-RF-IR on Rafale
    Rafale w. MICA-RF & IR
    (click to view full)
    MBDA’s MICA family. MBDA inherited MICA from the French firm Matra. It uses a guidance philosophy similar to AMRAAM’s, and has very good maneuverability. MBDA posts its range as 60 km. What’s different is that it comes in 2 versions, and is designed for use at all engagement distances. The MICA IR version uses infrared homing, like many short-range AAMs. This allows it to be used at close range, or used to conduct no-warning attacks at longer ranges, using advanced IRST (InfraRed Search and Track) type optronics that have become common on 4+ generation fighters. The MICA RF uses active radar guidance like AMRAAM, and is in service with France, Qatar and Taiwan.
    MBDA’s truck-mounted air defense version is imaginatively named the Vertical Launch MICA, and its ability to carry IR-guided MICA missiles allows effective operation in environments where turning on one’s radar will attract enemy strikes.
    RAFAEL’s Derby. Derby 4 looks a lot like AMRAAM, but it’s actually based on Israel’s own well-developed missile technology. It lists a 50 km effective range like AMRAAM, but this is questionable given its size and commonalities with the shorter-range Python 4; some observers place its range closer to 30 km. Derby 4 has been updated with a new seeker, has lock-on after launch capability for snap employment in short-range aerial engagements, and features its own programmable ECCM (Electronic Counter-Countermeasures) technologies. Apparently, it still lacks an in-flight datalink, and must rely on last-reported position before switching to active mode. Derby has been exported to a few countries, but is not yet in what one might call widespread use. This detailed review may prove useful.
    Derby has a ground-launched air defense system too: the Spyder combines 4 truck-mounted Derby and short-range 5th generation IR/imaging-guided Python 5 missiles, to create a versatile system adapted for use against a wider range of threats. A new Spyder 6×6 truck version was unveiled at Eurosatory 2006 that offered 8 missiles in any mix and puts boosters on all missiles to improve their range and performance. Customers include India’s order for 18 SPYDER systems of 5 vehicles each, and Peru’s buy of 6 systems.

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