Aircraft defensive aids systems are evolving as threats become increasingly more capable.
While many of the lessons to be learnt from the ongoing (2023) Russo-Ukrainian war have yet to be even formulated, one area that already stands out is the importance of conflict within the electro-magnetic spectrum. This is particularly true of air operations where manned and unmanned vehicles already find it difficult to operate in a contested environment without some form of electronic defence to protect them from ground-based weapon systems and counter air fighters.
Looking at the technology as a whole, the minimum cover available is a countermeasures dispenser that can accommodate anti-radar chaff, infra-red (IR) decoy flare and (increasingly) active anti-radar expendables together with warners that operate in the radar, IR and ultra-violet (UV) sections of the spectrum. Even here, sophistication is the watchword with dispensers needing to be ‘smart’ enough to manage inventory, programme active decoys and implement selected dispensing schemes. Again, such applications need to be integrated so that inputs from the available warners can be used as automatic prompts and are increasingly being teamed with active radar jammers in addition to any active off-board capability that might be available. Combinations of the type described are particularly suited to battlefield helicopters who by the nature of their role, are exposed to radar-guided gun and IR-guided missile threats. Examples of such systems include Aselsan’s HEWS, Elbit’s ALL-in-SMALL, Indra’s SIMBA-FD, Leonardo UK’s MAPPS and Terma’s MASE.
Examining these in more detail, the 342 pounds (155 kilograms) HEWS incorporates multi-channel radar (C-J band), laser (bands I through IV) and solar-blind UV missile warners that are controlled by a suite central processor and are augmented by the OZISIK countermeasures dispenser and an H-J band active jammer. This latter unit incorporates active electronically scanned array (AESA) and digital radio frequency memory (DRFM) technology and a combined receiver/techniques generator section. Overall, HEWS is intended for helicopter, transport and VIP jet applications. Elbit’s ALL-in-SMALL suite is also aimed at helicopter and transport applications and incorporates radar (0.5-40 GHz), laser (bands I through IV) and IR missile warning, has a suite controller embedded in its receiver section and offers countermeasures dispensing, radar jamming (Light SPEAR) and directed IR countermeasures (DIRCM – Mini-MUSIC) facilities.
Indra’s SIMBA-FD is designed to protect helicopters, wide and narrow bodied aircraft and UAVs, has a minimum weight of 66lb (30kg) (configuration dependent) and offers radar, laser and IR and UV missile warning. System control is exercised via an electronic warfare (EW) manager embedded in the suite’s ALR-400FB radar warner and countermeasures provision that comprises countermeasures dispensers and the company’s InShield DIRCM. Leonardo’s MAPPS system incorporates the contractor’s Miysis DIRCM, radar (C/D, E/J and K bands), laser (0.5-1.8um) and IR warners, is designed for helicopter and fixed-wing applications and is equipped with a Vicon countermeasures dispenser that is capable of handling the company’s BriteCloud active offboard decoy. Last but not least, Terma’s MASE architecture can be pod- or internally mounted, is designed for helicopter use and incorporates a ‘smart’ countermeasures dispenser system, the AN/ALR-69DK radar warner, the AN/AAR-54(V) UV warner and the company’s AN/ALQ-213(V) EW management unit. This latter element has been designed to integrate disparate, discrete sub-systems via a single controller.
Podded Systems
Mention of pod-mounted systems neatly segways into podded solutions as a means of defending smaller tactical aircraft. Amongst the most widely used legacy systems are Northrop Grumman’s AN/ALQ-135(V) and Raytheon AN/ALQ-184(V) radar jammers that have been used aboard US Air Force (USAF) and allied fighters. The latest generation of podded systems can be exemplified by the ELT Group’s (formerly Elettronica) EDGE and Elta’s Scorpius-SP systems, with Saab’s BOZ-EC equipment showing the benefits of pod upgrading packages. In the order given, the greater than 1,540lb (700kg) (configuration dependent) EDGE pod is designed for fighter and transport aircraft applications. As such, it incorporates a 0.7 to 40 GHz radar warning receiver, the contractor’s ELT-950 EW management system together with its multi-band (1-6, 4.5-18 and 26.5-40 GHz) VIRGILIUS radio frequency jammer. Again, EDGE is self-powered and self-cooled and incorporates DRFM technology, digital reception, solid-state transmit/receive modules and phased array antennas that offer electronic beam steering.
For its part, Elta’s Scorpius-SP (alternatively designated as the company’s ELL-8222SP equipment) is the latest generation of the contractor’s ELL-8212/8222 family of pod-mounted lightweight radar jammers. As such, Scorpius-SP makes use of AESA technology and is fitted with Gallium-Nitride (GaN) solid-state amplifiers. Designed to counter air-to-air and surface-to-air threats, other features include DRFM technology, accurate and rapid direction-finding and a wide frequency coverage. Interestingly, Elta has utilised the same technology to create the ground-based Scorpius -T multi-threat EW emulator system.
While Saab’s BOZ countermeasures dispensing pod is a legacy system, mention of BOZ-EC is made to illustrate the advantages of upgrading existing equipment. Effectively, the BOZ-EC package integrates Saab’s CIDAS-100 defensive aids suite into the existing BOZ shell, with the package resulting in a system that mates five BOP-L 39 pyrotechnic dispensers with a four-sensor missile warning fit. Again, the dispensers can dispense in a forward direction, to the side or downwards. This is important in today’s decoy environment as it is a major factor in positioning decoys that are in the right place to maximise their ‘attractiveness’ to a particular threat. Elsewhere, Saab is addressing this requirement with its DVM-200 architecture which is capable of dynamically changing its firing angle in order to provide an optimum self-protection effect. Like BOZ-EC, DVM-200 incorporates its own missile warning sub-system.
Before moving on from podded systems, it is worth noting that both the People’s Republic of China (PRC) and the Russian Federation make extensive use of countermeasures pods. In reverse order, Russian examples include the MiG-29M which can be equipped with a SAP-518 or KS-418 podded jammer (with which to complement its I-222 and L-150 electro-optical and radar warners) while the Su-25 is compatible with the SPS-141MVG jamming pod. Again, the pod-mounted L-203IE jammer is an option on the Su-27’s wingtip stations. In the PRC context, both the CAC FC-1 Xialong and J-10 Meng Long are compatible with the 6.5 to 17.5 GHz KG300G podded radar jammer and H-6 strike aircraft have been photographed off Japan equipped with underwing pods that are likely to be either a signals intelligence gathering equipment or a radar jammer.
EW Suites
At the top end of the food chain are a range of fully integrated, high-technology EW suites that are designed for ‘big beast’ platforms such as the Eurofighter Typhoon, the Boeing F-15EX, the Lockheed Martin F-16 Block 70/72, the Lockheed Martin F-35 and the Dassault Rafale. Taking these in the order given, the Typhoon is equipped with the multi-national EuroDASS consortium’s (Leonardo in the UK, the ELT Group in Italy, Indra in Spain and Hensoldt in Germany) Praetorian suite. Here, Praetorian includes radar, laser and missile approach warning, an electronic support measures capability, a defensive aids suite control computer, radio frequency jamming, a countermeasure dispensing sub-system (capable of handling active offboard expendables) and a towed decoy application. Most recently, Leonardo (EuroDASS lead) has developed a Praetorian upgrade package that is intended to form part of the Eurofighter Phase 4 Enhancement effort. Designed to increase the platform’s survivability, the upgrade package is intended to integrate the suite with the AESA radars that are being introduced for export (ECRS Mk 0) Typhoons together with German (ECRS Mk 1), Spanish (ECRS Mk 1) and UK (ECRS Mk 2) examples. Within the package, Hensoldt is taking the lead on a new digital receiver that will be more effective against complex emitters, while Indra is developing a system frequency band extension that will be able to handle the most modern dense and complex environments. Other elements include improved signal processing hard and software, an enhanced wingtip pod cooling system (from the ELT Group) and integration with the jamming capabilities inherent in the ECRS Mks 1 and 2 AESA radars. At time of writing, subsystem flight trials had been undertaken, with trials aboard a Typhoon aircraft scheduled for 2024.
Elsewhere within the Typhoon (together with those of the F-35 and Saab’s Gripen) orbit, the UK is funding the development of the MBDA SPEAR-EW stand-in jammer and decoy. Weighing over 220lb (100kg), the 2+ metre long by 180mm diameter SPEAR-EW is based on MBDA’s SPEAR stand-off weapon and is designed to carry a modular EW payload that is capable of both jamming and decoying “across the threat spectrum”. Other features include inertial navigation with GPS, pre-programmed flight parameters and a two-way datalink with its launch platform. For Typhoon and Gripen, MBDA is developing a three round SPEAR family launcher while the F-35 would carry the device internally.
In the F-15 domain, BAE Systems’ AN/ALQ-250 Eagle Passive Active Warning Survivability System (EPAWSS) has been developed for retrofit to USAF F-15E/EXs. On the F-15E, it replaces the aircraft’s legacy AN/ALR-56C radar warning receiver, AN/ALQ-135 jammer and its AN/ALE-45 countermeasures dispenser. Billed as leveraging fifth-generation fighter EW technology (presumably the F-35), AN/ALQ-250 features include modularity and scalability, all aspect broadband radar warning and geolocation, interoperability with an AESA radar (the AN/APG-82(V)1) and a 50 percent increase in chaff and flare capacity. As originally planned, the USAF intended to retrofit 217 F-15Es with the system to be followed by installation aboard 144 new-build F-15EXs. Again, the first EPAWSS equipped F-15E was scheduled to be fielded during US Fiscal Year (FY) 2023, with F-15EX fits following in FY2024.
Alongside the AN/ALQ-250, BAE Systems has also produced the AN/ALQ-239 Digital EW System (DEWS) which is to be installed (alongside the AN/APG-82(V)1 AESA radar) aboard 68 Japanese Air Self-Defence Force F-15J interceptors. As far as can be ascertained, ALQ-239 appears to be an extremely close relative to ALQ-250 and like the latter, is intended for both retrofit and new-build applications. At the time of writing (2023), AN/ALQ-239 is likely to be incorporated aboard Indonesia’s F-15EX buy if such a sale is consummated.
Somewhat confusingly, the BAE Systems EW suite for the F-35 is designated as the AN/ASQ-239 which offers radar warning (with an electronic support capability) together with radio frequency and IR countermeasures. As might be expected, information relating to the ASQ-239 remains sparse bearing in mind its classification and its manufacture only talks in generalities about the system which is known to be tightly integrated with the platform’s radar and electro-optic sub-systems. As such, BAE characterises the suite as offering “360-degree situational awareness, all aspect radar warning and geolocation, simultaneous jamming, targeting support and self-protection”. Alongside its very nature, one of the suite’s more intriguing aspects is its association with the Lockheed Martin ‘Skunk Works’ Speedracer aerial decoy with which it could possibly be networked in flight. According to US press reports, Speedracer is (or was) an autonomous adjunct system that could function as a decoy, a jammer, a sensor platform or a kinetic munition and which could be both expended or (if possible) recovered.
Elsewhere in the American orbit, the L3Harris Technologies’ AN/ALQ-211A(V)4 (designated as the Advanced Airborne Integrated Defensive EW Suite or Advanced AIDEWS) is the latest generation of L3 Harris Technologies AIDEWS podded or internally mounted warning and jamming system that has been installed aboard a number of offshore F-16s including those of Pakistan and Turkey. As such, Advanced AIDEWS features a C-J band warning sub-system that is combined with an E-J band jammer. Other features include a stand-alone radar warning and techniques generator configuration, an AESA interoperability interface and the use of DRFM technology. The F-16 (in its Block 70/72 configuration) is also the target platform for L3’s AN/ALQ-254(V) Viper Shield all-digital EW suite. AN/ALQ-254 features commercial off-the-shelf (COTS) technology and an interface for the AN/APG-83 AESA radar. Like ALQ-211, ALQ-254 includes radar warning and jamming sections and system components comprise a multi-function display, four pre-amps, two transmitters, a C-D band receiver and a receiver/processor/techniques generator unit.
Returning to Europe, this review ends with consideration of three more ‘high end’ defensive aids suites that have been developed by the ELT Group (its integrated EW suite or IEWS), Saab (Arexis Fighter EW) and Thales (SPECTRA). In reverse order, SPECTRA is the integrated EW suite that Thales and MBDA have developed for installation aboard France’s multirole Rafale. As such, the suite incorporates radar, missile and laser warning, radio frequency jamming and countermeasures dispensing. Within the consortia, MBDA produces the missile warner and at the time of writing, Rafales had been supplied to/were on order for the Egyptian Air Force, the Greek Air Force, the French Air Force and Navy, the Indian Air Force and Navy and the Qatari Air Force.
For its part, the ELT Group’s IEWS makes use of the contractor’s VIRGILIUS family of equipments to provide the IEWS’s electronic support measures and radar jamming sub-systems, with other system elements including the 0.5-40 GHz ELT-162 radar warner, an IR/UV missile warner, the ELT-950 EW manager, the ELT-577 IR jammer and the ELT-590 DRFM-based expendable active decoy. Again, the suite’s active countermeasure sub-systems include coverage of the 2-18 GHz radar band and the X- and Ka-bands via its active decoy.
Saab’s Arexis Fighter EW application can be installed internally or be mounted in a pod. Threat coverage is across the very high frequency to Ka-band in both the sensing and jamming domains and the architecture as a whole interface with its host system’s computer or a defensive aids system controller as appropriate. As an internal package, Arexis weighs in at between 154- 330lb (70-150kg), while the podded version weighs between 660-1,322lb (300-600kg). Other system features include the use of GaN AESA technology (including an L- to Ka-band AESA fit as an option) and Ka-band jamming as another option. At the time of writing, Arexis-type equipment was understood to be flying on the Gripen E/F, with a pod demonstrator having been flown during 2017.
As was the case with the preceding discussion of podded systems, it is worth noting that both the PRC and Russia have fielded or are developing fully integrated airborne EW suites. In the Chinese case, the XAC JH-7 is reported to be fitted with the RKL-800A integrated system which is said to include a KJ-8602 or RW-1045 radar warner, a Type 960-2/KG-8605 noise radar jammer and two Type 942-4G countermeasures dispensers. For its part, the Su-24M strike aircraft carries the BKO-2M EW suite that comprises the L-67 control computer, the SPO-155M radar warner, an L-082 IR missile warner, SPS-161/162 active radar jammers (SPS-161 covering the 7.5-10 GHz band, with SPS-162 an output within the 5-7 GHz band) and an APP-50A countermeasures dispensing sub-system. Elsewhere, the Su-57 is fitted with an L-402 application that incorporates a control computer and three UV-50-01 decoy launchers that are compatible with active offboards. In the helicopter domain, the Ka-52 battlefield attack helicopter is fitted with an L-370P2 EW system that comprises an L-140 laser warner, an L-370-2 UV missile warner, an L-370 IR jammer, four UV-26 decoy dispensers, an L370-1 radar warner and an L370-3 radar jammer. What level of integration is incorporated here is uncertain.
Beyond the systems described here, the remainder of this decade can expect to see increasing levels of artificial intelligence and/or machine learning in the world’s airborne EW systems together with ever increasing levels of integration, multi-functionality and networking with ‘loyal wingmen’ to take on threat environments more safely.
by Martin Streetly
