Spoofing and Jamming: Detection and Defense

By Dr. Manfred Wittig, Global Navigation Satellite System Expert

This article is a continuation of the article “Global Navigation Satellite System – Technology and Threats“.

Satellite navigation systems are part of the infrastructure we use every day. However, disruptions to this infrastructure have also become commonplace. A distinction must be made between intentional and unintentional interference:

• Intentional or deliberate interference is the illegal transmission of false navigation signals. Such an act is punishable almost everywhere on our planet, but is nevertheless carried out on a large scale.
• Unintentional interference is caused by technical deficiencies in electronic devices. For example, inverters in photovoltaic solar systems have recently become potential sources of interference for GNSS receivers.

Spoofing

To detect interference, the interference source must first be identified and possibly localized. Detecting jamming signals and false GNSS signals (spoofing) is a delicate matter, because the nominal navigation signals are very weak and hidden in the thermal noise of the dedicated receivers. The requirements for a GNSS jammer/spoofer detector are very contradictory: Very weak and unknown signals below the noise level must be detected and displayed very reliably within a very short time frame of approximately 0.01 seconds over a very wide frequency range (typically up to 20 MHz bandwidth). These requirements are so contradictory for communications engineers that the general answer is: Such a device is not feasible.

Based on measurements of GNSS jamming signals from a satellite 600 km above the Earth’s surface over Ukraine and Syria, and with the goal of reliably detecting very weak signals, Prof. Dr. Otto Koudelka and Dr. Manfred Wittig have developed a device that meets these requirements. Such a device was extensively tested and the required performance was demonstrated through measurements under reproducible conditions in a special test area on the Earth’s surface and in the adjacent airspace.

The detailed technical specifications can be found in the following document:

About the Author

Dr. Manfred Wittig is a key figure in the field of satellite communications and navigation. As a project manager at the European Space Agency (ESA), he has contributed significantly to the development of European satellite communications systems and, as a coordinator at the European Union, to the development of navigation systems (especially EGNOS).

Prof. Dr. Otto Koudelka

Prof. Dr. Otto Koudelka is a renowned expert in space communications and satellite technology and was head of the Institute of Communications Networks and Satellite Communications at Graz University of Technology. Koudelka is, among other things, the Principal Investigator of TUGSAT-1, the first Austrian satellite, launched in 2013 as part of the BRITE constellation.

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