The Outside of the Envelope

This is an article published in our Airborne Electronic Warfare Compendium from June/July 2017.

USAF’s F-22A fighters
The USAF’s F-22A fighters are one platform that could benefit from the current research being performed via DARPA’s ARC programme. (USAF) 

The continued proliferation of both military and commercial RF (Radio Frequency) equipment, means that airborne EW will continue to remain as important, if not more so, in the future.

Travis Slocomb, vice president of electronic warfare systems at Raytheon stated to Armada that: “Electronic warfare is clearly growing in importance, particularly … with the proliferation of commercial technology.” He continued that: “The need for airborne EW systems and capabilities exists where there are air-to-air and surface-to-air threats.” In addition to the important role that ELINT (Electronic Intelligence) collection plays in supporting operations on the ground (see introduction): “The threat is always the driver. It evolves quickly and is becoming increasingly dynamic as adversaries exploit commercial technology. As the threat continues to evolve, so will the need for airborne EW.” At the same time: “The combination of threat advancement and ageing airborne EW systems has customers looking for new or upgraded electronic warfare capabilities,” stated Steve Morais, director of engineering at BAE Systems, while at the he observed, countries around the world are seeking to minimise expenditure.

Looking towards the future, The Defence Research Advanced Projects Agency (DARPA) which develops emerging technologies on behalf of the United States Department of Defence hopes to migrate technology developed by BAE Systems for DARPA’s Adaptive Radar Countermeasures (ARC) programme onto current and future United States Air Force (USAF) combat aircraft, sources close to the programme have informed Armada. The ARC programme commenced in 2012, and BAE Systems began its work on the initiative in 2013. According to DARPA’s official literature, the goal of the ARC programme is to: “automatically generate effective countermeasures against new, unknown and adaptive radars (surface-based and airborne) in real-time in the field.” To this end, the ARC architecture is designed to: “isolate unknown radar signals in the presence of other hostile, friendly and neutral signals. Deduce the threat posed by that radar; Synthesize and transmit countermeasure signals to achieve a desired effect on the threat radar. Assess the effectiveness of countermeasures based on over-the-air observable threat behaviours.” The need for the ARC architecture, which will develop signal processing and algorithms to achieve these goals, DARPA continued, is to enable the next generation of radar warning receivers to detect radar signals transmitted by systems employing complex and agile waveforms and frequency-hopping techniques to reduce their probability of detection and interception. This is distinct from legacy analogue radars which have traditionally employed fixed transmission frequencies, and hence been easier to detect.

In early November 2016, BAE Systems was awarded a contract by DARPA to commence Phase 3 of the programme worth $13.3 million. Phase 2 of the project, which was also led by BAE Systems, demonstrated the ability of the ARC architecture to characterise radar transmissions and to then adapt a countermeasures response to address such threats. Phase 3 will complete algorithm development for the ARC initiative, and work on transitioning the ARC architecture to USAF aircraft. Confidential sources informed Armada that installation of such technology could be seen on USAF platforms such as the Lockheed Martin F-35A Lightning-II and F-22A Raptor fighters, plus future platforms such as the Northrop Grumman B-21 Raider strategic bomber.

USAF’s F-22A fighters
The USAF’s F-22A fighters are one platform that could benefit from the current research being performed via DARPA’s ARC programme. (USAF)


Alongside technological developments such DARPA’s ARC programme airborne electronic warfare as a will continue to benefit from increasing levels of technological sophistication. As this compendium has illustrated, airborne ELINT and EW practitioners are dealing with a radio spectrum which has, in many parts of the world, unprecedented density. As Professor David Stupples, director of electronic warfare research at City University, London noted the challenge today and in the future will continue to be teasing the signals of interest out from the overall RF (Radio Frequency) environment. This can be helped with ELINT and EW systems already onboard aircraft which: “are carrying a tremendous amount of signal processing allowing real time analysis of signals, with decision analysis.” At the same time, as noted by Guy Alon, Israel Aerospace Industries’ ELTA Systems division’s electronic warfare director: “The traditional way to collect ELINT in the past has been at the platform level, by using dedicated aircraft for example. Today, you may collect ELINT from a wide variety of platforms, airborne and otherwise, which might not have ELINT collection as their primary mission.” At the heart of IAI’s philosophy in this regard is the utilisation of a modular approach toward the design and development of its airborne systems. This focuses on: “using the same technological core which we can scale up or scale down according to the platform that the EW system will equip, whether that is a large aircraft, or a small Unmanned Aerial Vehicle (UAV).”

Managing Information

Prof. Stupples continued that all of this ELINT has to be assembled to provide an accurate real-time Recognised Electronic Picture (REP) of the RF environment during an operation or during the day-to-day activities of any military in peacetime. This is a trend observed by Mr. Alon who added that: “Our customers would like to have all their ELINT delivered to one place, a command and control centre for example, so that it can be viewed in real time.” In operational theatres, he continued, such a REP will need to be shared with aircraft however the issue of available communications bandwidth will remain a challenge in this regard, Prof. Stupples believes. Tactical Data Links (TDLs) such as the North Atlantic Treaty Organisation’s (NATO) Link-16 which provides secure voice and data communications across a frequency range of 969 Megahertz/MHz to 1.2 Gigahertz/GHz has a bandwidth sufficient to carry data at rates of between 2.4 kilobits-per-second (kbps) to 16kbps. Link-16, which provides the TDL bedrock during NATO air operations is set to remain as NATO’s standard TDL in this regard for at least the next decade, if not beyond. Given that such TDLs might be insufficient to handle distributing a real time REP, Prof. Stupples argued that one option to sidestep the bandwidth challenge would be to download a version of the REP into an aircraft’s mission computer when it is on the ground prior to a mission, and instead use the TDLs to update this picture on the aircraft as and when changes occur.

The Market

Many companies involved in the airborne EW domain are confident regarding the market, predicting that the demand for their wares will continue to rise: “We believe that global demand for electronic warfare equipment should see slow growth over the next decade, reaching $20 billion by 2026,” predicts a written statement from Elettronica. BAE Systems is in agreement. Steve Morais, the company’s director of engineering stated that: “The global electronic warfare market is incredibly healthy, with industry analysts projecting its continued growth at a rate of three percent over the next several years.” Dave Appleby, vice president of sales for electronic warfare at Leonardo’s airborne and space systems division is in agreement: “The market for airborne EW is in fine health, indeed it is expanding as governments and their ministries of defence recognise the need to understand how their adversaries are using the electromagnetic spectrum and to protect their assets from modern radar-guided threats.”

Mr. Applby believes that the market is being driven by the changing nature of the threats faced by the world’s air forces: “During the largely asymmetric conflicts in Iraq and Afghanistan, airborne EW was limited to the protection of forces from fairly low-tech heat-seeking threats such as MANPADS (Man-Portable Air Defence System) surface-to-air missiles.” He added that: “current and future conflicts are much more likely to involve also facing sophisticated, RF-guided threats, and it is this requirement that is now driving the market.” Elettronica, meanwhile, observed that: “modern warfare is placing a greater emphasis on information superiority and situational awareness. This is expected to be a major factor in driving spending in this sector.” The firm continued that 36 percent of the growth during this coming decade will be dedicated to airborne EW systems and capabilities. Nevertheless, the company also stated that declining defence budgets in developing countries could hinder the growth of this market, although it is confident that demand from North America, the Asia-Pacific and Europe will continue to dominate.

by Thomas withington