Adversarial capabilities writ large have significantly improved vis-à-vis the United States (hence the necessity of the Defense Department's so-called third offset strategy). One of these areas causing concern is that of the electromagnetic spectrum (EMS).

Operations in EMS have become significantly more complex as adversaries have begun to develop advanced jamming capabilities utilizing software-defined technologies significantly more advanced and reprogrammable than Cold War-era analog systems.

For example, both China and Iran have touted electronic warfare payloads that can create headaches for opposing ground forces below. The Chinese Xianglong Soar Dragon UAS includes large payloads enabling it to conduct electronic warfare (EW) missions. The long endurance of the system, and most large UAS platforms, make them ideal to jam radar below.

"In wartime, the Xianglong's high altitude jammers would seek to disrupt not only the radars of enemy fighters and missiles, but also jam and spoof communications between enemy bombers, airborne early warning and control aircraft, drones and even datalinks between satellites, ships, land based missile launchers and missiles," Jeffery Lin and P.W. Singer wrote in Popular Science. "In such [a] role, the EW Xianglong would operate alongside a host of other Chinese EW aircraft, including Y-9 heavy transport jammers, J-16 and JH-7 strike aircraft, in both offensive and defensive operations."

A September blog post for the American Enterprise Institute, a Washington-based think tank, indicates that Iran might have "augmented its UAV fleet with drones capable of jamming enemy communications and disrupting communications between an adversary's drones and its controllers," though the article expressed skepticism over the claim's accuracy — be it realized or aspirational — given that "the Iranian press often exaggerates."

Several U.S. military officials from various service branches as well as the Pentagon have conceded that electronic warfare has been a neglected capability in the last 15 years given the intense focus on technologically inferior non-state actors in the Middle East and South Asia. This has led to an atrophy in capabilities on which the Pentagon wants to improve.

"The pace of change worldwide suggests that the U.S. needs agile, adaptive, and integrated EW capabilities," a DoD spokesman told C4ISRNET in an email. "We develop capabilities in the electromagnetic spectrum (EMS) to counter an adversary's use of electronic attack (EA) with the electronic protection (EP) of U.S. systems and, when necessary, to degrade, neutralize, or destroy enemy combat capability."

The way in which these capabilities have advanced overtime is the advancement of software capabilities enabling rapid reprogramming of signals. One of the defensive measures derived to counter these advancements is commonly termed cognitive EW. While coined as such, it's essentially applying machine learning to make systems smarter, according to Josh Niedzwiecki, director of sensor processing and exploitation at BAE Systems.

Niedzwiecki told C4ISRNET that when an adversary is trying to jam friendly forces, cognitive anti-jamming technology is able to automatically learn and understand the jamming signals, adapting techniques to minimize the jamming effect.

Describing how complex this environment has become, he said in decades past when forces would deploy to a theater and observe a type of jamming signal, frequency, wavelength or bandwidth, troops would collect evidence and take it to a laboratory for analysis and countermeasure development. Months later, a countermeasure or antidote would be programmed in the system and used in theater. The advances in software and reprogrammable radios make this previous paradigm infeasible, he said, leading to a new shift in leveraging machine learning.

"Adversary radars are rapidly evolving from fixed analog systems to programmable digital variants with agile waveforms and unknown behaviors," the DoD spokesperson said. "Current airborne electronic warfare (aerial EW) systems must first identify the threat radar to determine the appropriate preprogrammed electronic countermeasure (ECM) technique. This approach loses effectiveness as radars evolve from fixed analog systems to programmable digital variants with agile waveforms and unknown behaviors."

Defense Advanced Research Projects Agency Director Arati Prabhakar, provided a useful vignette for why this technology is important to employ for friendly forces. Aircraft, upon deploying for a particular mission, have a library of profiles to counter an adversary's attempt to jam its radar. "We need a way today to deal with the changes that are happening on the ground," she said at the Atlantic Council in May regarding a growing sense of inadequacy versus advanced threats and adversaries.

Aircraft are "getting pinged by radar signals that we’ve never encountered before and it’s just one reflection of how rapidly technology is changing in the world," she said. "When that happens today, it can be weeks to months to literally years before they’re able to get the kind of protection they need against that new radio signal."

Prabhakar explained that machine learning and cognitive EW can "scan the radio spectrum in real time to determine what the adversary’s radar is doing, and then right there on the spot create a jamming profile that will protect those aircraft in real time in the battle space even when the world around them is changing."

In terms of research and development projects, the DoD spokesman identified DARPA’s Adaptive Radar Countermeasures (ARC) program, which aims to enable airborne EW systems to automatically generate effective countermeasures against new, unknown and adaptive radars in real time in the field.

"ARC technology is being designed to isolate unknown radar signals in the presence of other hostile, friendly and neutral signals," he said. "It then determines the threat posed by that radar, synthesize and transmit countermeasure signals to achieve a desired effect on the threat radar, and assess the effectiveness of countermeasures based on over-the-air observable threat behaviors."

These technologies will be developed using an open architecture to allow for insertion, modification and removal of software modules with minimal effect on other elements of the system, the spokesman said, noting that algorithms and signal processing software will be suitable both for new EW systems as well as retrofitting existing EW systems.

The spokesman added that "potential adversaries attempt to use EA as an asymmetric counter to our precision guided munitions (PGM). The department applies EP measures to restore PGM effectiveness."

While Niedzwiecki was hesitant to say that newer, more advanced software-based jamming tools are dual use — in that the tools used to jam can also leverage the same technology to defend against jamming — he said the underlying algorithms are the same.

On the offensive side, the name of the game is stealth. Today’s warfare complex is distinctly different than in previous generations. Deputy Secretary Work described at the annual Association of the United States Army conference in October that the "old adage was … if you can be seen you can be hit, and if you can be hit, you can be killed. The new adage is if you emit, you die."

Niedzweicki described how a brute-force jamming method — in which an incoming aircraft will jam enemy radar by radiating noise in the environment so the radar does not pick up the aircraft’s signature — is not completely effective because it is loud in that while the radar can’t pick up the aircraft signature, an adversary still knows something is out there.

A quieter approach is better, tailoring a signal the radar is emitting so as to jam the enemy with as little energy as possible and not alert the enemy to your presence.

Items such as jamming pods, including the next-generation jammerthat will be outfitted on the EA-18G Growler, described as the most advanced airborne electronic attack platform, serve as loud jamming platforms and serve in environments for which it is safer to operate and thus emit, Niedzweicki said.

The F-35, for its part, also boasts advanced electronic warfare capabilities.

"Our efforts will ‘extend the attack surface’ through the employment of networked unmanned vehicles. Spatial separation of forces complicates an adversary's defenses while increasing our own reach for coordinated kinetic or non-kinetic (EW or cyber) attack," the DoD spokesman said.

While the threats of certain platforms such as Chinese and Iranian drones flying high above jamming signals might be far-fetched or difficult to verify, the threat posed by these technologies is real. It is real given the growth in the cognitive EW space, Niedzwiecki said, adding that technology is being pushed in commercial industry for commercial application of machine learning, meaning everyone has access to these technologies —  a concern that exists for all domains and technologies expressed by top defense officials.

For the U.S. it is about operationalizing these commercial technologies in a way faster and more efficient than adversaries that is at the core of the third offset strategy.

Mark Pomerleau is a reporter for C4ISRNET, covering information warfare and cyberspace.

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