Modern jamming: drones, quantum and AI

Modern defence requires modern jamming, writes JJ DeLisle* for Mouser Electronics.

Jamming is a critical electronic countermeasure that involves transmitting undesired signals at carefully calibrated power levels and modulations to be captured by enemy receivers. These signals disrupt the target receiver’s ability to process desired signals, thereby degrading the enemy’s access to crucial information. This article introduces the latest electronic jamming technologies and their essential role in rapidly evolving electronic warfare (EW) strategies.

Role of jamming in EW

RF communications are prolific and diverse technologies used in defence, government, civilian and industrial applications on land and in the air, sea and space. When discussing jamming in an EW setting, it typically means intentionally disrupting an enemy’s RF radar, sensing and communication technologies. Radar systems have historically been deployed on naval vessels, aircraft, land-mobile platforms and fixed installations to target systems for guided weapons platforms.

Considering the multitude of potential systems to jam, operators must be strategic. A key element of jamming is deciding if a particular sensing system or communication is a threat or strategic target. Most countries have spectrum regulatory agencies that segment the electromagnetic spectrum into frequency bands for specific use cases. Investigating the frequency of transmissions in certain bands is one method of identifying potential threats or targets. Other parameters may include emission duration, energy distribution, modulation and repetition. Extensive libraries and algorithms exist to identify emissions based on these and other factors in an effort to determine if they should be subject to jamming.

Once an operator has decided to jam a signal, the system needs to be programmed with the appropriate parameters for jamming. These parameters are generally derived from the target emissions or known identity of a given radar, sensing or communication system. The operator must also determine the target’s vector and distance relative to the jamming system. The jamming system can then be activated with emissions specifically designed to disrupt the target’s capability.

Evolution of the EW landscape

In early jamming systems, high-power signals were directed toward the sensitive receivers of radar and communication systems to overload the receivers and degrade their signal-to-noise ratio (SNR). In addition to degrading the SNR, such overloading can damage a receiver. Current jamming methods have become more sophisticated and may be used alongside spoofing or other EW techniques to inject signals with deceptive characteristics. A simple jamming operation would require high jammer emissions from a source that can often be easily identified. This approach may disable a single radar system from identifying targets, but enemy operators would know the system is being jammed.

More advanced techniques may involve sending a signal alongside a radar reflection that, when processed, would make the radar target appear to be something else. For example, a support jamming aircraft in a stand-off or within an escort may inject a spoofing signal that makes the aircraft appear to be several birds or different styles of aircraft. This is why radar jamming is often extended to include deception, accounting for how jamming techniques have evolved to include more sophisticated electronic countermeasure options.

As jamming has evolved, radar and communication systems have become more resilient to jamming methods. Defeating jamming is a high priority for communication and radio navigation systems, whose receivers are particularly susceptible to jamming and denial. One common method is to deploy many diverse radar types in a region, making it difficult for a jamming system to identify and target every potential radar threat. Other methods include using low probability of detection (LPD) and low probability of intercept (LPI) radar and communication techniques, such as wideband spread spectrum and frequency-hopping systems (ie, agile systems). As a majority of modern systems are now software-defined, the signalling methods can be changed on the fly to thwart traditional jamming methods.

Many new radar, sensing and communication systems operate over extremely wide bandwidths and may even include several segments of the spectrum, making these systems increasingly hard to identify and defeat. Moreover, new generations of RF sensing and communication systems use cognitive radio techniques leveraging machine learning (ML) and artificial intelligence (AI). These new (and sometimes retrofitted) systems can intelligently respond to interference and jamming threats at incredible speeds and learn from each engagement.

Other changes include uncrewed systems becoming more prevalent during conflicts. In the past, the primary concern was uncrewed aerial systems (UAVs), or drones, which were generally rather large and operated much like traditional aircraft. Now, there is no shortage of uncrewed systems, including land-mobile robots, UAVs and naval systems. These new uncrewed systems may have sophisticated surveillance payloads alongside communication and radar systems. In some cases, uncrewed systems are used as mesh networks or communication relay systems vital to battlefield communications. Disabling these distributed multi-node systems is now the main challenge and requirement in suppressing enemy communication and sensing capabilities.

Many governments are developing and testing quantum radar and communications, though quantum technology is still considered speculative. This technology uses entangled quantum particles to instantaneously relay signals at potentially vast distances. Because quantum radar, communication and navigation systems do not include an accessible transmitter/receiver channel to intercept or inject signals into, they are poised to present an incredible challenge for future jamming systems to defeat.

Latest electronic jamming technologies

In every arms race, as soon as a competitive technology is developed, there is a rush to provide a countermeasure. The same goes for jamming, radar, sensing and communication systems. As communication and radar systems have increased in bandwidth and agility, so have jamming systems. To defeat LPD/LPI systems, jamming systems with wider bandwidth and more sensitive detection methods have also emerged. To counter distributed radar, sensing and communications systems that intercommunicate and coordinate with sophisticated algorithms, jamming systems that operate on the same principles have been devised. Using active electronically scanned arrays (AESAs), array antenna technology and advanced jamming systems capable of detecting and targeting multiple threats, coordinated platforms now serve as a strategic approach to counter modern mesh radar and communications.

Moreover, modern jamming systems use more sophisticated algorithms and ML/AI to coordinate and defeat jamming targets. Using sophisticated intercommunicating sensor systems along with coordinated jamming systems can significantly increase detection and interception capabilities and improve jamming efficacy. Incorporating ML/AI to perform signal processing on intercepted signals can also aid jamming efforts by more rapidly and accurately identifying and categorising the system’s generating signals and determining which methods will best defeat the target. In a world where both communication systems and jamming systems are using ML/AI to optimise their detection and response capabilities, the advantage will likely go to the systems with the best adaptive design and computation speed (Figure 1).

Furthermore, militaries are developing and testing ML/AI techniques that autonomously perform many of these functions, including coordinating swarms of autonomous robotic systems. Jamming such systems is becoming increasingly vital for advanced militaries to compete in asymmetric engagements where low-cost, highly accessible uncrewed robots and drones can rapidly be weaponised and controlled with off-the-shelf commercial technologies.

Figure 1: Basic block diagram of an AI-based EW system. (Source: Mouser Electronics)¹. For a larger version, click here.

Combating these distributed threats also requires distributed jamming and detection capability. This is why some militaries are even developing jamming systems designed to be carried into combat or deployed on robotic assistive systems. These are likely designed to protect ground troops and land-mobile and robotic systems from inexpensive UAVs that are either remotely piloted (thus requiring a communication link) or autonomous and requiring a guidance system that can be jammed.

With quantum radar and communications still largely theoretical, jamming and defeating quantum systems is also theoretical. Some quantum radars will eject entangled particles that collide and rest on target surfaces; it may be possible to defeat these radars by stimulating the attached particles with disruptive signals. Other methods may include attacking the quantum sensing or communication system’s supporting electronics, not the quantum channel itself.

Conclusion

The future is here; with widespread drone and ML/AI use in EW, the complexity of jamming on the modern battlefield is skyrocketing. EW sensing and communication systems are becoming more sophisticated every year, and jamming technology must advance even faster to defeat these new systems. It is still uncertain if this is even possible with quantum radar and communications, and many governments and militaries are awaiting this verdict.

*Jean-Jacques (JJ) DeLisle attended the Rochester Institute of Technology, where he graduated with a BS and MS degree in Electrical Engineering. While studying, JJ pursued RF/microwave research, wrote for the university magazine, and was a member of the first improvisational comedy troupe @ RIT. Before completing his degree, JJ contracted as an IC layout and automated test design engineer for Synaptics Inc. After six years of original research — developing and characterising intra-coaxial antennas and wireless sensor technology — JJ left RIT with several submitted technical papers and a US patent. Further pursuing his career, JJ moved with his wife, Aalyia, to New York City. Here, he took on work as the Technical Engineering Editor for Microwaves & RF magazine. At the magazine, JJ learned how to merge his skills and passion for RF engineering and technical writing. In the next phase of JJ’s career, he moved on to start his company, RFEMX, seeing a significant need in the industry for technically competent writers and objective industry experts. Progressing with that aim, JJ expanded his company’s scope and vision and started Information Exchange Services.

_{1. https://ieeexplore.ieee.org/document/9292960}

Top image credit: iStock.com/dr_evil

Originally published here.