Electromagnetic Effects and Threats

Relevance of Electromagnetic Interference in Safety Analyses

In many areas of society, there are facilities that we cannot do without; they must be available at all times. Examples include critical infrastructures such as communication networks, hospitals and the power grid. Their operation is increasingly safeguarded by complex technical equipment and IT systems.

Given the ongoing security discussion, there is a previously unfamiliar aspect that deserves attention: the deliberate disruption of electronic systems by high power electromagnetic signals, referred to as “intentional electromagnetic interference” (IEMI). Powerful transmission devices can discreetly disrupt equipment, even from a distance of 100 meters and more. The potential consequences within the system context can be severe. Another commonly used term of such electromagnetic disruptions of high power is “high power electromagnetics” (HPEM).

Detection as Part of a Security Concept

As a result, significant efforts have been dedicated to the development of a robust receiving and measuring apparatus capable of registering the otherwise imperceptible exposure to extreme interference signals in the first place. In this context, Fraunhofer INT’s Business Unit “Electromagnetic Effects and Threats” (EME) has undertaken several iterations of work to develop a comprehensive detection system. More specifically, the aim was to implement not just a mere warning functionality, but also to quantify and record any disruption signals in as much detail as possible, enabling forensic analysis afterward. Additionally, determining the direction of the threat is also helpful for immediate countermeasures.

Forensic Detection System - FORDES

Performance characteristics

In its current development iteration, the forensic HPEM detection system, as conceptualized at Fraunhofer INT, incorporates the following characteristics, setting it apart in various aspects from other solutions on the market:

• Detecting the interference frequency as a characteristic parameter of narrowband signals
• Particularly precise determination of the field strength by frequency response compensation whilst maintaining a high measuring dynamic
• Determining the incoming direction of the signals
• Capturing essential parameters in case of pulsed disturbances
• Compact form factor for expanding on possible use cases while maintaining a high level of self-protection
• Additional battery mode of operation for compensating power outages and enabling mobile use
• Accessible graphical user interface

System Concept

In the processing chain of the input signals, the following steps are being carried out:

• Spiral antennas capture electromagnetic signals with high field strength
• Attenuators weaken the signals for protecting the electronics
• The signals are processed, digitized and temporarily stored
• Frequency and key pulse parameters (pulse width, pulse number, etc.) are determined
• Further data processing is taken on by a built-in single board computer
• The system is connected to a network via an optical interface
• System control and data display are carried out through a web interface developed in-house

The detection unit itself will be set up in proximity of particularly sensitive systems which could possibly be deemed suitable targets for disruption, e.g. a data centre or control room. Visual data assessment will be conducted on a PC situated in a presumably less exposed area. Nonetheless, the well-protected system will independently log any events in local storage for subsequent analysis.

Technical Properties

The system features the following technical properties:

• Recognising HPEM threats at frequencies up to 10 GHz and field strengths way beyond 10 kV/m
• Measuring the field strength from 100 V/m onwards up to some kV/m, including forensic assessment of HPEM parameters in the frequency range between 500 MHz and 8 GHz.
• The system itself is shielded against even higher field strengths
• Battery operation for up to 10 hours
• Cubic outer housing with 19 cm edge length

Within the context of protection schemes against electromagnetic disturbances, a detection system plays an essential role. Therefore, our goal is to consistently adapt the system through further development stages to match the prevailing intended use cases. Our most recent iteration exists as a laboratory demonstrator.

• EMC is the acronym used for “Electromagnetic Compatibility”. This is the discipline in engineering sciences investigating to what extent electronic devices and systems can disturb neighbouring devices by their own transmissions or be disturbed by them in turn. Before products can be entering the market, their compliance with specific test standards needs to be verified.
• HPEM stands for “High Power Electromagnetics” and designates as an umbrella term phenomenon connected to the generation of intense electromagnetic radiation patterns or conducted voltages and currents. If these do occur, electronic systems can be disturbed or damaged. The strength of interference would usually exceed by far (electric field strength > 100 V/m) the stress conditions electronic devices are submitted to during qualification tests for electromagnetic compatibility (EMC).
• HPM is a shorthand for “High Power Microwaves”, representing a sub-category of HPEM that has specifically been in use in the past for designating (pulsed) narrowband signals with field strengths beyond 100 (500) V/m or radiated power levels larger than 10 MW.
• IEMI abbreviates “Intentional Electromagnetic Interference”, designating the intentional use of electromagnetic radiation or signals meant to disturb or damage electronic systems for terroristic or criminal purposes.