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Vital in combat

Combat aircraft are increasingly reliant on electronic warfare systems integrating warners, jammers, chaff and decoys, writes Mark Hewish

Despite the proven value of electronic warfare (EW) systems in reducing aircraft losses, a combination of technology failures, program mismanagement and insufficient funding has resulted in many high-value platforms flying combat missions without adequate protection. An inability to provide a robust defense even against known threats can dramatically curtail air operations in an era when combat losses are deemed unacceptable. Serbia's deployment of 1970s- vintage SA-6 surface-to-air missile batteries during the 1999 conflict over Kosovo effectively grounded many of the NATO aircraft participating in Operation 'Allied Force' while they remained active.

Small and/or vulnerable targets - such as fighters, attack helicopters and any type supporting special operations - require a high level of EW integration in order to maximize their level of protection within the size, weight and power-generation constraints imposed by such platforms. These demands have generally led the sponsors of such developments to adopt a unique combination of subsystems - sometimes with minor variations to meet individual national operational, funding or industrial considerations - that best meets their needs. This becomes the de facto standard for that aircraft, since few export customers wish to incur the cost and risk associated with introducing alternative equipment.

On the other hand, the security considerations associated with supplying advanced EW equipment to an overseas customer - particularly in the area of access to software - has led some countries to embargo the sale of such facilities. This may be overcome by the customer specifying its own nationally developed hardware and/or software. Several countries that do not (or no longer) develop their own designs of combat aircraft, notably Israel, have strong EW industries. This allows them to meet national needs and to compete effectively in the export market.

The more widely used a platform is, both in terms of the number of customers and the roles in which it is employed, the greater the likelihood of it being equipped with different EW fits. Industrial consortia find it worth their while to promote individual items - or even complete integrated systems - that are different from those originally specified. These may be installed from new, exploiting technology that has become available since the aircraft itself was designed, or introduced as upgrades. This area of the EW business is perhaps the one most affected by the industry consolidation of recent years, which has led to erstwhile sister companies having new owners and former competitors finding themselves part of the same organization.

The simplest way to introduce new EW facilities for which the platform was not designed is to mount them externally, often in pods that may be carried on any suitable stores station. This approach has the added benefit of allowing a given capability to be implemented only when it is needed, with other sensors or weapons being carried on the same hardpoint at other times. Companies in Scandinavia have taken this concept further by integrating EW systems into missile pylons, leaving them free to carry their normal weapon load.

SaabTech Electronics in Sweden has designed its BOL family of countermeasures dispensers to fit within pylons that carry air-to- air missiles. Danish company TERMA Industries Grenaa (TIG - formerly Per Udsen Co Aircraft Industry) offers a broad range of pylon- integrated systems to equip fighters such as the F-16 and F/A-18. The Royal Danish Air Force (RDAF) operates more than 50 examples of the Electronic Combat Integrated Protection System, in which an AN/ALQ-162 jammer is installed in the pylons mounted on two wing stations of its F-16s. TIG has also delivered more than 600 units of its Pylon Integrated Dispensing System (PIDS) - each accommodating three AN/ALE-40 or AN/ALE-47 chaff dispensers - to equip F-16s of the Belgian, Danish and Dutch air forces, together with those of the US Air Force Reserve and Air National Guard (ANG).

The PIDS+ variant, which can carry three missile-approach warners (MAWs) in addition to two chaff dispensers, has undergone flight trials aboard an F-16 under a program sponsored by the Danish, Dutch and Norwegian air forces, with additional participation by the ANG. PIDS Universal adds a MIL-STD-1760 stores-management harness that allows it to carry the latest generation of US-developed weapons. The Pylon Accommodated Self-protection Suite is a similar development for the F/A-18.

TIG's parent company, TERMA Elektronik, originally developed the AN/ALQ-213 Electronic Warfare Management System to equip RDAF F-16s. The system's ability to control a wide variety of dispensers, radar warning receivers (RWRs), MAWs and jammers has subsequently led to its deployment aboard fighters, helicopters and transport aircraft in Australia, Belgium, Germany, the Netherlands, Norway, Portugal and the US.

France's weapon system

One of the marketing strengths of the French aerospace industry is that it can offer a complete weapon system - fighter aircraft, weapons, radar and other sensors, and EW system - as a package, with governmental approval to supply all elements. The Spectra integrated self-protection suite for the Rafale fighter incorporates the DDM (Detecteur de Depart Missiles) infrared MAW. The aircraft will carry two such units mounted at the tip of its tailfin.

Production DDMs are already being delivered to equip French Air Force Mirage 2000Ds, being installed at the rear end of the two launchers for Magic 2 air-to-air missiles. The Mirage 2000D also carries the Spirale countermeasures system, using dispensers integrated into the aircraft's dorsal spine. The 63 Mirage 2000s of various models ordered by the United Arab Emirates carry the ECLAIR system, with 48 infrared flares being mounted beneath the rear fuselage in place of the braking parachute. Thales (formerly Thomson-CSF Detexis) is promoting its SPS-FA integrated self- protection systems for fighter aircraft, together with the PAJ-FA jamming pod.

The UK Defence Procurement Agency (DPA), which sponsored a Fast Jet Missile Approach Warning System Technology Assessment Programme in the mid-1990s, plans to proceed with procurement of such a capability to protect Tornados, Jaguars and Harriers. The DPA has also invited seven companies - BAE Systems, Litton, Northrop Grumman, SAGEM, Sanders (since absorbed into BAE Systems), Shorts Missile Systems and Thomson-CSF Optrosys (now Thales) - to submit proposals by the end of 2000 to conduct the Fast Jet DIRCM [Directed Infrared Countermeasures] Technology Demonstration Programme. This would conclude in mid-2003 with demonstrations of a pod-mounted installation that is smaller, lighter and draws less power than current DIRCM systems. Any operational derivative would be internally mounted.

SaabTech Electronics (formerly CelsiusTech Electronics) has developed the EWS 39 integrated suite for the Swedish Air Force's Gripen multirole combat aircraft. The EWS 39 is a modular, software- driven system that incorporates a processor, RWR and an internal jammer. SaabTech completed production of the AR830 first-generation RWR for the Gripen in 1999. According to the company, this was the first such system to provide real-time pulse de-interleaving and library-based emitter identification.

In November 1999, Sweden's FMV defense procurement agency awarded Saab AB Gripen a SKr1.2 billion (US$127 million) contract to complete development of the EWS 39. Ericsson Saab Avionics has overall design responsibility, with SaabTech receiving about half of the total funding to finish development of the new BOW-21 RWR. This adds a narrowband superhet receiver to the existing wideband instantaneous frequency measurement (IFM) receiver, together with more powerful and compact signal processors running upgraded algorithms.

Unlike traditional designs, the narrowband receiver is a four- channel device with full monopulse capability. This allows it to detect any signal that falls within its bandwidth, including continuous-wave emissions and those with high pulse-repetition frequencies. The local oscillator is a high-speed synthesizer, permitting optimized search based on library information. According to the company, the combination of a precise synthesizer and a digital frequency discriminator (DFD) provides high frequency accuracy (1MHz) and resolution.

The wideband receiver is a four-channel amplitude monopulse design with high dynamic range and a high-resolution DFD. Both receivers have their own video processors, which independently characterize every pulse. The narrowband receiver normally operates in search mode, but can also be cued by the wideband device.

The standard fit for the Gripen consists of four antennas, at the fore and aft ends of wingtip pylons, providing toroidal coverage. Increasing the number to six confers spherical coverage. Options include extending the frequency coverage down to C/D-band, and up to K-band, together with interferometric receivers. The last of these increase direction-finding accuracy from 7 to 1. The addition of a digital receiver significantly improves selectivity and passive ranging performance. SaabTech has already developed countermeasures dispensers for the Gripen and other aircraft under a separate contract.

The Luftwaffe has selected a variant of BOW-21 to upgrade its Tornado multirole combat aircraft. That service has also introduced the Tornado Self Protection Jammer pod, supplied by EADS in collaboration with Israeli company ELTA. Elisra is developing an integrated EW suite for the Israel Defense Force's latest F-15I variant. The company also provides its SPS-20(V) and SPS-1000V-5 RWRs for a variety of platforms, together with the SPJ-20 self- protection jammer.

BAE Systems' Australian operation has developed the ALR-2002 RWR, which successfully completed initial flight trials aboard a Royal Australian Air Force (RAAF) F/RF-111 in September 2000. The company is proposing the ALR-2002B variant for Phase 2 of the RAAF's project Air 5376 to upgrade its F/A-18s, and the ALR-2002D version for installation aboard Australian Army S-70A Black Hawk helicopters. The RAAF has also ordered EL/L-8222 jamming pods from ELTA, in conjunction with Vision Abell, to equip its F-111s.

Avitronics in South Africa has developed a family of EW subsystems that can be installed individually or as part of an integrated suite, such as the company's Multi-Sensor Warning System (MSWS), to equip aircraft ranging from fighters to helicopters and transport aircraft. The MSWS can include Avitronics' RWS-50 RWR, LWS-400 laser warner and MAW-200 missile warner.

In developing its RWS-50, the company has adopted a design philosophy of "fit for, but not with" in order to keep the initial cost low, while permitting easy and cost upgrading if and when it is deemed necessary. The LWS family of laser warners, which are designed to interface with an existing RWR/ESM system, provides threat classification and direction finding (DF) against laser range-finders, designators and missile-guidance systems. The sensitivities of each sensor configuration - LWS-200, LWS-300 and LWS-400 - has been chosen to provide warning at ranges that are generally 1.5 times the threat's engagement range.

The MAW-200 employs what Avitronics describes as a unique optical design - incorporating advanced filters, purpose-built image- intensifier tubes and photon-counting focal-plane-array processors - to provide high sensitivity. Each ultraviolet sensor is served by a dedicated high-performance digital signal processor, making use of highly pipelined command execution and parallel processing.

EW delays

The development and deployment of many airborne EW systems in the US is in a state of disarray. Programs that were launched as joint- service efforts, with the aim of reducing overall costs and achieving commonality, have crumbled as their sponsors have withdrawn. This has further delayed developments and increased their cost, at a time when budgets were already shrinking, to the point where niggling technological problems can threaten an entire program.

Perhaps the most extreme example is that of the AN/AAR-57 Common Missile Warning System (CMWS), led by the US Army as part of the Advanced Tactical Infrared Countermeasures (ATIRCM)/ CMWS effort. At the outset, the AN/AAR-57 was also planned to equip aircraft of the US Air Force (USAF), Navy (USN) and Marine Corps (USMC). The program entered engineering and manufacturing development (EMD) in 1995, with the lead platforms reflecting this tri-service involvement: the MH-60K helicopter operated by the US Army's special forces, the USMC's AV-8B and the USAF's F-16 Block 40s allocated to close air support. The program was restructured in FY99, with EMD being extended by two years.

The USAF effectively withdrew from the program in the latter half of that year, by cancelling production funding (although it continues to support the development phase). The service may yet outfit its A- 10s, although operational testing aboard that platform is not planned until 2004. Support by the USN has also waned. Operational testing on the AV-8B is not planned to take place until that on the A-10 has been completed, and the sensors are being repackaged for the F/A-18E/F. Testing of the more compact sensors aboard that platform is not expected to take place until 2004.

The USAF is, however, proceeding with other programs. The service is enhancing the capabilities of the Tactical Electronic Warfare System (TEWS) aboard its F-15Es by implementing the Suite 4 update, which adds a Band 1.5 jamming facility, to the Northrop Grumman AN/ALQ-135 Internal Countermeasures Set (ICS). The ICS has already been upgraded by introducing a Band 3 capability, which provides 'robust' jamming techniques against modern pulse-Doppler radars. The latest enhancement improves the aircrew's situation awareness, cues both active and passive countermeasures operating in the Band 1.5 frequency spectrum, and adds a waveform-selection feature to optimize jamming against specific threats. The service hopes to deploy 162 units at a total cost of approximately US$370 million.

The USAF plans to further upgrade the ALQ-135 to Suite 5 standard by introducing the Fiber Optic Towed Decoy (FOTD) being developed by BAE Systems (formerly Sanders - see below), but it recently extended the duration of engineering and manufacturing development for this effort by 24 months. Boeing will now complete integration of the decoy with the F-15 in September 2005.

The Raytheon AN/ALQ-187 is a fully integrated internal jammer for the F-16 and other tactical aircraft. It can form part of the Advanced Self-Protection Integrated Suite (ASPIS) promoted by Litton Advanced Systems, which additionally includes that company's AN/ALR- 93(V)1 RWR/controller, the BAE Systems AN/ALE-47 threat-adaptive countermeasures dispensing system and the AN/AAR-60 Missile Launch Detection System (MILDS) ultraviolet MAW developed in collaboration with EADS in Germany.

The Lockheed Martin AN/ALR-56M RWR is a form and fit replacement for the ALR-69 in the F-16 Block 40 and other aircraft, providing improved performance in a dense signal environment and enhanced detection of modern threat signals. Litton Advanced Systems also offers an upgrade kit for the ALR-69 and earlier ALR-46, consisting of the CM-518 digital processor and the AM-9101 E/J-band receivers, the upgraded version being designated AN/ALR-91(V)3. The company has additionally developed the LR-105 RWR and precision targeting system for the F-16 Block 60. The LR-105, a highly modified adaptation of the LR-100 electronic support measures (ESM) system (see below), combines the NexGen digital receiver chipset with Litton's patented Long Baseline Interferometer passive geolocation technology.

USAF F-16s participating in Operation 'Allied Force" carried the Raytheon AN/ALE-50 Towed Decoy System both in its pylon-mounted version and, in the latter stages of the campaign, integrated into that company's AN/ALQ-184 self-protection pod. The (V)9 variant adds four launchers to the baseline pod. Technique co-ordination between the two systems is managed by an advanced correlation processor that determines whether the ALQ-184 or the ALE-50 is the most effective counter to a given threat.

Northrop Grumman's AN/ALQ-131 is the standard jamming pod with the USAF in Europe, equipping F-16s and other types. Other operators include the US Air National Guard and Reserve, and 11 overseas countries. Belgium and Egypt introduced upgrades during 1999, the latter receiving 39 Block II conversion kits. The ALQ-131 has also undergone flight trials in conjunction with several towed decoys, including the ALE-50 and BAE Systems' Ariel.

Northrop Grumman continues to upgrade the pod by inserting technology from other programs, including its Tactical Radar Electronic Combat System (T-RECS) and Miniature Air Launched Decoy (MALD). The former contributes digital radio-frequency memory jamming techniques and expanded, newly developed modulation types; the latter provides an upgraded processor (with about 100 times the capacity of the baseline system, from a 'throwaway' board) and memory. Other efforts involve adoption of Northrop Grumman's microwave power modules (MPMs) to address problems of obsolete parts, while increasing modularity, reliability and maintainability.

Northrop Grumman has supplied more than 600 examples of its AN/ALQ- 162 Shadowbox jammer to equip aircraft operated by the US and six overseas countries, including the F-16, F/A-18, AV-8B and special- operations. The system is available in internal, pylon-mounted and podded installations. Norway and Denmark are upgrading their ALQ- 162s by adding a capability against pulse-Doppler radars, together with a more modern processor and expanded memory. Norway is also introducing MPMs, which more than double the output power.

The USN's tactical-aircraft EW programs are focused heavily on the F/A-18 family. The Raytheon AN/ALR-67(V)3 Advanced Special Receiver (ASR) entered full-rate production in late 1999 to equip the F/A- 18E/F. The USN now plans to install the ASR aboard only 150 F/A- 18C/Ds in addition to its F/A-18E/Fs, with the remainder of the earlier model receiving upgrades to their ALR-67E(V)2s. The (V)4 variant of the ASR is undergoing a two-phase upgrade program for the AV-8B and F-14, which the USN accelerated by a year as a result of a US$5 million FY99 Congressional 'plus-up'. Phase I, conducted during FY00, improved sensitivity and detection range. Phase II, planned for FY02, will enhance target identification by upgrading the processor and memory.

The AN/ALQ-165 Airborne Self-Protection Jammer (ASPJ), developed by a joint venture between ITT Avionics and Northrop Grumman, has undergone a strange evolutionary process. Following completion of operational evaluation in 1992, the Director of Operational Test and Evaluation assessed that ASPJ was not operationally effective or suitable for the F/A-18. The program was therefore cancelled, and production was terminated. About 100 systems - sufficient to equip the entire planned F-14D ground-attack fleet - had already been delivered, however. The USN therefore fielded the existing ASPJ systems aboard those aircraft.

Following the shooting down of a USAF F-16 over Bosnia in 1995, the USN recognized that the only system rapidly available to improve F/A-18C/D survivability against similar threats was ASPJ. Contingency deployments aboard USN and USMC F/A-18C/Ds continued as those on the F-14D began. A Congressional plus-up in FY97 provided US$48 million for an additional 36 ASPJ systems, deliveries of which began in June 1999. The service intends to use these as a rotatable pool to equip three squadrons of USN/USMC aircraft that can be forward-deployed for contingency operations.

The USN was able to receive further ASPJs because the production line had remained open to fulfil export sales. The Finnish and Swiss air forces have deployed ASPJ aboard their F/A-18s, and the Republic of Korea Air Force (ROKAF) has fitted the system to its F-16s. The first ROKAF aircraft carrying ASPJ entered service in February 1999, and the service recently placed a third production order that will extend deliveries until 2005.

Following the original cancellation of ASPJ, the USN began development of the AN/ALQ-214 Integrated Defensive Electronic Countermeasures (IDECM) system in FY96 to equip the F/A-18E/F. IDECM was planned as an offboard jammer only, using the AN/ALE-55 FOTD, with a complementary onboard jammer being introduced as a possible upgrade. In March 1999, as a result of technical problems and delays encountered by IDECM, the USN decided to develop an onboard jammer to ensure that the F/A-18E/F would have a self-protection suite available during its initial deployments.

This led to a three-phase program, the first of which (IDECM Block I) combines an upgraded variant of ASPJ with the ALE-50 off-board decoy system. Raytheon completed deliveries of Multiple Platform Launch Controllers (MPLCs) from the second production lot in December 1999, bringing the total to 65. This was sufficient to equip the F/A-18E/Fs from the first low-rate initial production (LRIP) batch that participated in operational evaluation. A modified version, the Integrated MPLC, has been under development concurrently. This has the added ability to control the ALE-55 FOTD. The IMPLC is planned to equip all production F/A-18E/Fs, beginning with the second LRIP batch.

The second interim configuration, IDECM Block II, will introduce the onboard element of the ALQ-214 Radio Frequency Countermeasures (RFCM) system in place of ASPJ, while retaining the ALE-50 as the decoy. Transition to this configuration depends on RFCM successfully completing operational evaluation, scheduled for the end of FY01, which would lead to production beginning a year later.

The RFCM system is a joint development by ITT Industries' Avionics Division and BAE Systems (formerly Sanders). The former company supplies the onboard techniques generator (involving a receiver, processing system and transmitters), with the latter providing the ALE-55 FOTD and its deployment canister. The RFCM program was restructured in July 1999, to accommodate the cost increases and schedule slippage resulting from problems encountered during testing of the FOTD, its launcher assembly and integration of the various system components. Developmental test and operational assessment was completed in March 2000, using an F/A-18D testbed aircraft that had been modified to carry F/A-18E/F avionics, and full-rate production is now due to begin in 2002. IDECM Block III, the final planned configuration, will involve replacing the ALE-50 with the ALE-55.

Large aircraft EW

Helicopters and large aircraft such as airlifters, tankers and surveillance platforms may seem to have little in common, but they often employ the same EW equipment. For example, the UK is buying 131 examples of the Northrop Grumman AN/AAQ-24 Nemesis DIRCM system - which includes the AAR-54 ultraviolet MAW - to equip several types of helicopter and fixed-wing aircraft, while US Special Operations Command has ordered 60 shipsets for tanker/transport and gunship variants of the C-130.

The Franco-German Tiger attack helicopter will carry the Threat Warning Equipment (TWE) self-protection system developed by industry in the two countries, with Thales acting as systems integrator and prime contractor. The TWE combines a broadband RWR developed by the French company with a laser warning receiver from DASA (now part of EADS) and the Saphir-M countermeasures dispensing system. The TWE also acts as the overall EW systems manager, being able to interface with additional equipment such as missile warners and jammers. The German Army's Tigers, and its NH90 transport helicopters, will also be equipped with EADS' AAR-60 MILDS missile warner (involving a total of 214 installations).

Thales is also promoting its Self-Protection System for Helicopters (SPS-H) as an integrated, standalone fit that can be tailored to almost any rotary-wing platform. Subsystems within SPS-H include the TDS-H radar warning receiver, MWS-20 missile approach warner and Alkan ELIPS countermeasures dispenser, all of which are in production to equip French Air Force and Army helicopters. The SPS-H can also include a laser warner, various types of jammer, and alternative offboard countermeasures.

Elisra provides several systems suitable for either helicopters or transport aircraft, including the SPS-65(V) combined radar and laser warning receiver, the LWS-20V-2 laser warner and the Passive Airborne Warning System (PAWS) missile warner.

The Helicopter Self-Protection System (HSPS) offered by South African company Avitronics combines elements of its MSWS (see above) with countermeasures dispensing systems from companies such as SaabTech Electronics and W Vinten. Many of the features of HSPS were driven by operational requirements for the Rooivalk attack helicopter. Export contracts include one from the United Arab Emirates to equip its Puma tactical support helicopters.

The AN/ALQ-212 Advanced Threat Infrared Countermeasures (ATIRCM) system is part of the US Army's Suite of Integrated IR Countermeasures (SIIRCM), which additionally includes the new Advanced Infrared Countermeasures Munitions family and signature- reduction features. The latter involve engine exhaust/heat suppression and special coatings. ATIRCM consists of an active IR jammer for use aboard helicopters and the passive AN/AAR-57 Common Missile Warning System (CMWS). BAE Systems (formerly Sanders) successfully concluded contractor sled testing aboard a US Army EH- 60 helicopter in August 2000. Developmental flight testing was due to follow. Full-rate production was scheduled for the third quarter of FY03. Under present plans, ATIRCM/CMWS will equip the AH-64, UH- 60, CH-47, EH-60 and various special-operations aircraft.

The AN/ALQ-211 Suite of Integrated RF Countermeasures (SIRFC) is planned to equip the US Army's AH-64D Longbow Apache attack helicopters, together with the MH-47Es and MH-60Ks operated by the service's Special Operations Command, and selected UH-60s and CH- 47s. A variant is scheduled for installation aboard the USAF Special Operations Command's CV-22 tilt-rotor aircraft. In December 2000, the US Army announced its intention to award ITT Avionics a five- year contract that includes full production.

The ALQ-211 is a fully integrated self-protection suite that incorporates the Advanced Threat Radar Warning Receiver and Advanced Threat Radar Jammer (ATRJ). The passive portion is expected to identify threats with better than 90% certainty. It calculates signal angle of arrival, and determines the range of emitters, with very high accuracy. On platforms equipped with GPS receivers and digital maps, it can identify, geolocate and display the position of threats. SIRFC prioritizes simultaneous threats based on the operating mode and jams with the appropriate techniques. According to ITT Avionics, the system is the first active countermeasures suite having sufficient effective radiated power and advanced jamming techniques to defeat multiple pulse, pulse-Doppler, continuous-wave and monopulse radars simultaneously.

In the case of the CV-22, SIRFC will act as the overall manager of the EW suite in addition to providing threat warning and situational awareness. The ALQ-211(V)3 RWR - a standalone variant of the radar warning subsystem within SIRFC - forms part of the integrated survivability system for the US Army's new RAH-66 Comanche scout/attack helicopter. Boeing has awarded ITT Avionics a contract to supply 14 aircraft sets for the EMD program. Other elements of the system include a laser warning receiver and point chemical detector. ITT Avionics is also supplying High Power Remote Transmitters (HPRTs), which are compatible with SIRFC, to equip MH- 47Es and MH-60Ks. The HPRTs operate in conjunction with the helicopters' ALQ-136A(V)2 pulse jammers and ALQ-162 continuous-wave jammers.

The USAF Special Operations Command is enhancing the situational awareness and threat-avoidance capabilities of its 38 MH-53M Pave Low IV deep-infiltration helicopters under the Interactive Defensive Avionics System/ Multi-Mission Advanced Tactical Terminal (IDAS/MATT) program, for which Lockheed Martin Systems Integration - Owego acts as prime contractor.

A single display shows information from all onboard EW systems, including the ALR-69 RWR, forward and aft ALQ-162 jammers, ALE-40 countermeasures dispensing system, ALQ-157 IR jammer and AAR-47 MAW.

Litton Advanced Systems delivered more than 200 examples of the AN/APR-39(V)2 RWR during 1999, partly as a result of a US$4 million Congressional plus-up. The unit completed follow-on test and evaluation aboard the USMC's AH-1W Cobra in November 1999. The APR- 39A(V)2 employs a highly sensitive multireceiver architecture and can act as the controller for integrated EW suites.

Litton is also promoting several other variants of the family. An upgrade kit for the APR-39A(V)1 improves that system's ambiguity resolution, sensitivity, pulse-density handling and processing capability, while also adding a continuous-wave capability. The APR- 39B(V)1 upgrade additionally adds Litton's Smart Multi-Function Display, which overlays threat data on a digital moving map. The APR-39 Viking III combines an inexpensive crystal video receiver with a tuned radio-frequency receiver, providing detection and direction-finding of continuous-wave and pulse-Doppler radars as well as frequency measurement for improved ambiguity resolution.

The operating profile of naval helicopters enables them to glean substantial intelligence information, leading to their being equipped with ESM systems. Examples include the Royal Australian Navy's S-70B-2 Seahawks, which carry the Elisra AES-210/E; S-70Bs of the Turkish Navy and the Royal New Zealand Navy's SH-2G Seasprites, fitted with Litton Advanced Systems' LR-100; and the UK Royal Navy's Merlins, which employ the Kestrel system developed by Thales Defence (formerly Thomson Racal Defence).

The Danish, Dutch and Portuguese air forces have enhanced the survivability of their C-130s by installing RWRs, MAWs and ALE-40 dispensers, with integration being performed by TERMA Industries Grenaa. The installation involves a total of 20 dispensers - 16 in the fuselage, and four (for flares only) in the nosewheel bay - and wingtip pods carrying the RWR antennas. Portugal has adopted the Northrop Grumman AAR-54 as its MAW for this application, as has the Luftwaffe to equip its C-160 Transalls.

Thales is supplying its TDS-TA radar warning receiver and MWS-20 missile approach warner to equip the French Air Force's transport aircraft, aboard which they operate in conjunction with Alkan chaff and flare dispensers.

The UK Royal Air Force will equip Nimrod MR.4 maritime-patrol aircraft with the DAS 2000 defensive-aids system, for which Lockheed Martin is acting as integrator. The suite includes the High Power Fiber Optic Towed Decoy developed by Raytheon, incorporating Northrop Grumman MPMs, for which Thales Defence is providing its Shrike techniques generator.

The USAF introduced its first B-1Bs incorporating the ALE-50 towed decoy system in January 1999. Four such aircraft participated in Operation 'Allied Force' in the spring of that year, during which the ALE-50 was credited with defeating at least eight missile attacks. Modification of the entire B-1B fleet is scheduled for completion in FY04.

The USAF originally saw the ALE-50 as an interim improvement to the B-1B's survivability pending implementation of the Defensive System Upgrade Program (DSUP). This would have involved replacing the current AN/ALQ-161 defensive system with the ALR-56M RWR and IDECM (including its FOTD). As a result of the delays in the IDECM program, and the accompanying cost increase, the USAF has cancelled the B-1 DSUP in its original form and is considering alternatives.

Boeing recently selected Lockheed Martin Systems Integration - Owego to provide new ESM systems for the USAF's B-52H bombers. They will replace the current ALR-20A RWR, providing advanced threat detection and location, precision targeting and jammer cueing. The ESM system will operate in conjunction with the AN/ALQ-155 and AN/ALQ-172 jammers. Northrop Grumman is developing an upgraded version of the ALQ-155, incorporating elements from its ALQ-135 and ALQ-165 (ASPJ) systems. ITT Avionics is enhancing the performance and reliability of the ALQ-172 under a series of technology upgrades. The ALQ- 172(V)3 variant provides AFSOC AC-130H gunships with extended frequency coverage, while ECP 93 introduces upgrades to the AC-130U and MC-130E/H Combat Talon I/II.

Northrop Grumman has selected a team of Lockheed Martin Systems Integration - Owego and Anaren Microwave to supply a new ESM system that will replace the AN/ALR-73 aboard 21 USN E-2C Hawkeye airborne early-warning and control aircraft. The system is a variant of the AN/ALQ-210 family, designed to equip helicopters or fixed-wing aircraft. It combines advanced digital receiver technology with a militarized commercial architecture to provide significantly higher performance than the ALR-73, accompanied by a weight reduction of more than 70% and an eight-fold improvement in reliability.

The USAF is upgrading all 50 of its C-5B airlifters with AAR-47 missile warners and ALE-47 countermeasures dispensers under a program that is due for completion in March. The Sensors Directorate of the US Air Force Research Laboratory (AFRL) is conducting its Large Aircraft IRCM (LAIRCM) advanced technology demonstration (ATD) to develop subsystems and an overall integration scheme that could protect airlifters, tankers and similar platforms - including the airliners forming the Civil Reserve Air Fleet - from attack by IR- guided missiles. The USAF plans to spend US$370 million on the LAIRCM program by 2005, including installing the system aboard an initial 12 C-17s and eight C-130s.

LAIRCM combines MAWs with advanced directed laser jammers. The AFRL has awarded contracts under the Small Business Innovation Research program to examine MAWs using inexpensive sensors and advanced motion-detection algorithms. Other technologies under development include closed-loop infrared countermeasures that could provide high-power, threat-adaptable laser jamming to achieve a rapid seeker breaklock.