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GNSS Jammer detected in Graz

Researchers of TeleConsult Austria have been able to detect a GNSS jammer during an intensive measurement campaign in the vicinity of the airport Graz Thalerhof. These measurements have been performed within the GAIMS project.

Jammers can influence GNSS receivers within a distance of 1000 m significantly. This influence can lead to an inferior position accuracy, a wrong position or in the worst case to a total loss of the position, velocity and time solution.

Such a jammer has been detected on the 19th of August 2014 at 11:24 in the vicinity of the airport Graz Thalerhof. Different algorithms, developed during the GAIMS project, detected the jammer at the same time.

In the following plot, which depicts the power spectral density, the jammer influencing the E1/L1 band is clearly visible. Since the jammer transmitted for approximately 7 seconds, a so called "personal privacy device" installed on a truck/car passing by can be assumed. These "personal privacy devices" can be powered with the cigarette lighter in a car. The profile of the power furthermore supports the assumption of a passing by jammer.

Power spectral density

Moreover can the effect of the jammer also be seen at the carrier-to-noise-density ratios (CN0R) of the satellites. In the following plot, the theoretical CN0R values are shown with a dashed line, while the measured values are depicted with a solid line. While the jammer is passing by, the received signal strength of the satellites clearly dips.

Carrier-to-noise-density Ratio

Currently, the measurements are analyzed in more depths during the GNSS airport interference monitoring system (GAIMS) project and the GAIMS-II project.