The SAM busters


New Member
Feb 16, 2009
The SAM busters
Jane's Defence Weekly

Developments in suppression and destruction of enemy air defences (SEAD/DEAD) have had to keep pace with increasingly complex air defence systems. Tom Withington reports

Since Saddam Hussein's invasion of Kuwait in 1990, and the resulting US-led Operation 'Desert Storm' in 1991, major conflicts involving the US and its allies, with the exception of Afghanistan, have witnessed air forces grappling with the threat presented by modern surface-to-air missiles (SAMs) connected to sophisticated air-search and targeting radar as components of integrated air defence systems (IADSs).

At the same time several nations, including Iran and Venezuela, have poured investment into advanced so-called 'Double Digit' mobile SAM systems procured from the Russian Federation. As a result, air forces in Western Europe, along with their US counterparts, have had to stay abreast of today's air-defence threat and ensure that they have the technology to suppress and destroy such dangers in the face of declining defence budgets and competing military priorities.

The suppression and destruction of enemy air defences, better known by its SEAD and DEAD acronyms, traces its history back to the Second World War. However, it was over Vietnam where the US Air Force (USAF) and US Navy (USN) first deployed innovative tactics and technologies to suppress the threat presented by the air defences of the North Vietnamese Army (NVA). In those days this threat was chiefly presented by static SAM systems such as the Russian S-75 Dvina (SA-2 'Guideline'). Air defence technology has improved exponentially over the years, culminating in the double-digit systems proliferating today, which are of such concern.

The USN's S/DEAD capabilities took a major step forward in November 2009 when the US Department of Defense authorised full-rate production of the Boeing EA-18G Growler electronic warfare aircraft. The Growler has been procured as the successor to the Northrop Grumman EA-6B Prowler, which has been in service since the early 1970s. So far, the navy has received 17 Growlers, and will eventually receive a complement of around 85 aircraft.

Networked systems
The Growler will have its work cut out in protecting other strike aircraft against today's and tomorrow's air defences; today's IADS are complex, networked defensive systems that can share targeting information at high speed across increasingly robust datalinks. One result of this is that, while radar is still essential to provide a firing solution vis-à-vis an aircraft or strike package, a radar in one location can provide targeting information to a SAM battery some distance away, presenting a challenge to any aircraft carrying an anti-radiation missile (ARM) that hopes to destroy a radar and SAM battery with one attack.

Moreover, today's S/DEAD soft- and hard-kill weaponry is vulnerable to the 'switch off' technique by which radar is active for enough time to provide a firing solution for a SAM before being deactivated. The result of such a tactic is that an ARM can lose its 'fix' on the radar target once the system is deactivated. This tactic is not new: it has been utilised since the days of Vietnam when NVA radar operators realised that shutting down their equipment could cause an ARM attack to fail.

The so-called 'switch off' tactic has since been used by air defenders in Iraq and the Balkans. Moreover, even with radar switched off it is still possible for air defenders to create havoc by firing their SAMs 'ballistically' - without radar guidance - into the sky at suspected targets.

The combined result of the switch off tactic, the advent of mobile double-digit SAM systems, networked IADS and the use of unguided SAMs has resulted in a shift from the doctrine of SEAD, whereby the use of radar and SAMs would be degraded and damaged for the duration of a sortie or an air campaign, towards a doctrine of DEAD, which seeks to destroy air defences outright during hostilities. The simple rationale is that once the air defences are destroyed, they can no longer present a threat to the aircraft. The advent of mobile SAM systems such as the Russian-built S-300 PMU (SA-10 'Grumble'), S-300V (SA-12 'Giant') and S-400 (SA-20 'Triumpf'), as well as the means to perform the 'shoot and scoot' tactic that makes them highly difficult to target, places a high premium on destroying such targets as soon as they are discovered.

In terms of targeting mobile systems, the Raytheon AN/ASQ-213 R7 HARM (High-speed Anti-Radiation Missile) Targeting System (HTS) can hand off data regarding the positions of hostile radar to other strike aircraft, which may not necessarily be carrying ARMs but may have GPS-guided weapons sufficient to attack a hostile SAM system from beyond the latter's engagement envelope.

The AN/ASQ-213 R7 is designed to operate with the Raytheon AGM-88 HARM series of anti-radar missiles. Since its entry into service in the mid-1980s with the USAF and USN, the AGM-88 has become arguably the world's leading ARM and has saved the lives of countless aircrew. However, the AGM-88 has its own shortcomings, not least of which is its cost. One tactic used by the USAF and USN during Operation 'Desert Storm' was to fire scores of AGM-88s during the ingress and egress of strike packages of coalition aircraft into and out of Iraq. This tactic was designed to attack radar that were active, while convincing other air defenders to leave their radar switched off. In the first half of the first week of the 'Desert Storm' air campaign in late January 1991, up to 500 of the 5,000 AGM-88s used throughout the air campaign were launched. At a price of around USD200,000 per missile such a tactic becomes expensive. Furthermore, this tactic can also rapidly degrade missile stocks, which may take time to replace.

Risk of collateral damage
Another shortcoming of the AGM-88 design was that, once in the air, if the radar that the missile was targeting was switched off and the missile lost its location, the weapon could "take off like a mad dog", in the words of Lieutenant Michael Short, the Commander of the Allied Air Forces Southern Europe during Operation 'Allied Force' (OAF) over Kosovo and Serbia in 1999. The missile's behaviour can, therefore, pose a serious risk of collateral damage, especially when it is used above urban areas. During OAF an AGM-88 hit an empty house in the suburbs of the Bulgarian capital of Sofia, 80 km from its intended target.

Raytheon has worked to address these challenges via the HARM Destruction of Enemy Air Defense Attack Module (HDAM) programme for the AGM-88. At the heart of the HDAM upgrade is the addition of a GPS/inertial navigation system, which no longer renders the weapon dependent on radar emissions to perform a strike. It also helps to address the problem of the 'switch off' technique. As long as the location of the radar or SAM battery is known, the AGM-88 HDAM weapon can complete its attack. The HDAM-modified AGM-88 is expected to eventually furnish the USN and USAF.

Since production of the AGM-88 commenced in the early 1980s, it has been produced in numerous versions, including the AGM-88A and B, which featured a new reprogrammable seeker in the case of the latter. The AGM-88C, meanwhile, which includes an enhanced warhead and software enabling a 'home on jam' capability, is deployed widely through the USAF and USN on Lockheed Martin F-16CJ and USN and US Marine Corps (USMC) EA-6B and Boeing F/A-18 Hornet combat aircraft. ATK has since developed the AGM-88E Advanced Anti-Radiation Guided Missile (AARGM) modification that combines an active and passive millimetre-wave seeker and radar homing receiver with the airframe, warhead and motor of the Bravo and Charlie HARMs. The missile is expected to enter service with the Aeronautica Militaire Italiana (Italian Air Force) by November 2010.

During 'Desert Storm' the AGM-88 was deployed alongside BAE Systems' (now MBDA) ALARM (Air-Launched Anti-Radiation Missile). Unlike the AGM-88, ALARM was conceived as a self-defence missile that climbs after launch before deploying a parachute and drifting to earth, during which time its seeker watches for radar emissions before discarding its parachute and accelerating towards the emitter. The weapon is used by the UK Royal Air Force (RAF) and also the Royal Saudi Air Force, which has elected to outfit its Panavia Tornado IDS combat aircraft with the weapon during the Tornado Sustainment Programme.

The USAF and USN are arguably the only two services that retain large, dedicated SEAD and DEAD aircraft and units. For other air forces throughout NATO and the wider world, their SEAD and DEAD efforts will focus on protecting individual aircraft as opposed to suppressing or destroying air defences for a strike package. Across Europe, several air forces are procuring advanced 4.5-generation multirole combat aircraft that must perform a range of missions, including S/DEAD.

The USN has elected to continue its tradition of using dedicated electronic warfare (EW) aircraft for the SEAD/DEAD mission and is procuring the Boeing EA-18G Growler to replace its current EA-6B aircraft. The Growler includes a Northrop Grumman AN/ALQ-218(V) receiver that collects and analyses radar signals, transmitting this information to the aircraft's jamming system, which can then disrupt the threat. "The Growler provides full-spectrum electronic attack capability for the warfighter," says Philip Carder, F/A-18 communications manager. "Components of the system include the AN/ALQ-99 high-and-low-band jamming pods, the Raytheon ALQ-227(V)1 communications countermeasures set and the ITT Interference Cancellation System (INCANS), which enables the pilot to communicate while the aircraft is jamming.

One of the major benefits of the EA-18G is that it has the speed and performance to stay abreast with the F/A-18 carrier-based combat aircraft that the USN and USMC operates. The Prowler, which the EA-18G replaces, did not have the same high performance as its replacement and its participation in strike packages of Hornets to provide jamming and SEAD/DEAD protection was likened to 'an elderly grandfather on Halloween escorting trick or treaters on a sugar high'. A total of five Growlers will be able to support an embarked carrier air wing.

Although the Growler will initially be outfitted with the same AN/ALQ-99 jamming pods used by the EA-6B, these will eventually be replaced by a new system via the USN's Next Generation Jammer programme. Peter Joyce, Business Development Manager for the Next Generation Jammer programme at ITT Corporation, says that the AN/ALQ-99 replacement is likely to be a "podded system". ITT is one of four companies, which also include Boeing, BAE Systems and Raytheon, which are vying for selection as the preferred bidder for the programme. Joyce says that the USN will "down-select to two bidders for technology demonstration. Each team will build a prototype [system] and fly it on their own airplane. In around 2012, the navy will look at all those results and will look at a central supplier to go into the engineering development phase".

Joyce says the goal is essentially to get down to a single supplier by 2013. "All of the companies competing for the Next Generation Jammer programme are facing similar challenges regarding design because the electro-magnetic environment is denser and there's going to be a lot fewer Growlers than there were EA-6Bs. Because the threat has changed and because you have more modern threats, the navy wants much more jamming and power, and that's the whole thrust of this programme. How do you get more jamming beams and more power within those beams?" asks Joyce. "The obvious answer is to go towards electronically steered arrays."

Unmanned potential
For the short term, inhabited aircraft seem set to continue the S/DEAD mission. However, this mission has been mooted as ideal for unmanned aerial vehicles (UAVs) and particularly for unmanned combat aerial vehicles (UCAVs). By its very nature S/DEAD are deadly missions, and taking the pilot out of the cockpit represents an ideal way to reduce the risk to aircrew. Moreover, UAVs provide an excellent and cost-effective way to overwhelm IADS with scores of aircraft to mask strike packages or to convince an adversary that an attack is in progress before the real air campaign has begun.

The Israeli Air Force has successfully used UAVs for this purpose, notably during Operation 'Peace for Galilee' over Lebanon in 1982 where they were employed to confuse Syrian air defences. A similar tactic was later used by the US-led coalition at the start of 'Desert Storm'. Israel was able to fold its experiences of using UAVs as part of the S/DEAD effort into its Israel Aerospace Industries Harpy delta-wing UAVs, which have an endurance of up to two hours and a range of up to 270 nautical miles (500 km). A passive radar receiver provides the UAV with the location of a radar emitter, which can then be destroyed with a 70 lb (32 kg) proximity-fused warhead. Harpy is thought to have been exported to China, India, South Korea, Spain and Turkey.

Armed UAVs could be an ideal choice for the S/DEAD mission. Aircraft such as the USAF's General Atomics MQ-9 Reaper UAVs are already performing armed strikes on dangerous targets in support of coalition military operations in Afghanistan. However, the S/DEAD mission requires high performance airframes and weaponry that is reactive to threats as they are discovered, be they SAM launchers or radar activations, and which can also manoeuvre out of trouble if necessary. Current UAVs such as the Predator family might arguably not be so suitable for the S/DEAD mission, although the emerging UCAV demonstration aircraft such as the pan-European Dassault neuron technology demonstrator could lay the foundations for UCAVs that perform the complex manoeuvres and high speeds demanded of this mission and incorporate targeting and sensor systems that are highly reactive. The design challenges for the SEAD UCAV will be considerable. The aircraft will need to spot hostile radar emitters, prioritise the most threatening, receive information regarding the IADS order-of-battle from other UCAVs and action this information, launch weapons such as ARMs and hand-off targets to other UCAVs or other inhabited platforms: all functions that must be performed rapidly.

Moreover, if the S/DEAD UCAV is to earn its way onto the flight line it will need to perform all of these functions to at least the same standard, if not better, than the inhabited S/DEAD platforms that they will replace. Judgement will also be a vital feature of any future S/DEAD UCAV. Will the aircraft be able to determine the location of enemy SAM launchers and radar with absolute certainty? Will the UCAV's sensors provide enough information to the aircraft's operators to allow them to ascertain whether there is a risk of collateral damage if an ARM is fired to destroy the target?

UAVs and the ELINT role
UAVs could also have an important role to play in the electronic intelligence (ELINT) mission, which gathers details on the behaviour of enemy radar, enabling tactics to be devised by which these radar can be jammed or successfully attacked by ARMs. At present, the RAF uses the BAE Systems Nimrod R.1 in this role, yet the work of these aircraft is often shrouded in secrecy. The USAF makes use of the Boeing RC-135 Rivet Joint for similar purposes. However, all of these airframes are ageing and replacement platforms will have to be found soon.

The German Air Force has taken a revolutionary approach by replacing its Breguet Atlantic intelligence-gathering aircraft with a UAV-based solution. The force will procure the Northrop Grumman/EADS Eurohawk, based on Northrop Grumman's RQ-4B Block 20 Global Hawk UAV to perform the electronic intelligence (ELINT) mission. For this role the aircraft will carry an EADS ELINT payload and is expected to perform its maiden flight in 2010 and enter service with the air force by 2017.

These aircraft, which will serve with the 51ST Reconnaissance Squadron at Jagel, close to the German-Danish border, will offer up to 35 hours of endurance and will be able to collect ELINT, which can then be used by the air force's Panavia Tornado IDS combat aircraft and their AGM-88 missiles.

The fate of the RAF Nimrods was sealed in December 2009, with ex-USAF RC-135 aircraft being selected by the force to replace the R.1s. The RAF has reportedly been offered three aircraft to this end, for a cost of between USD750 million and USD2 billion (EUR512 million-EUR1.36 billion). However, the Rivet Joint is an old design and the hypothetical length of their service lives with the RAF, should the force decide to purchase this aircraft, remains unknown.

Although the RAF is not thought to have discussed using a UAV such as the Eurohawk as a replacement for the R.1s, such an acquisition could cost around USD1.1 billion (EUR751 million) based on the USD550 million (EUR375 million) development cost for the German aircraft and the circa USD110 million (EUR75 million) price tag for each of the five aircraft that Germany will acquire. However, the Eurohawk could give the RAF up to 35 hours endurance compared with the 15 hours endurance of the Rivet Joint and would also require a fraction of the aircraft's complement of around 27 crew members to operate. Moreover, the USD1.1 billion would buy five Eurohawks as opposed to three Rivet Joints.

UAVs offer a number of options vis-à-vis SEAD and DEAD platforms for tomorrow's air campaigns as do the new variants of ARM weapons and electronic warfare aircraft that are entering service.

Air defence design and sophistication has not remained static since the days of Operation 'Desert Storm' and is unlikely to do so in the future. The future technology available for the SEAD/DEAD missions will no doubt remain similarly fast moving.

Tom Withington is a JDW Correspondent based in Paris

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