The GPS jamming that has disrupted flights and shipping across Europe due to conflict in recent years does not stop at the clouds. It also reaches Earth observation and communication satellites in space hundreds of kilometres above Earth, shows new research from DTU Space at the Technical University of Denmark.

The researchers have analysed and mapped areas over Europe where jamming disrupts some satellites' ability to determine their own position.
Based on analysis and publicly available data, they have written a scientific paper and created a free online map, SAT-JAM, showing where satellites experience GNSS interference, including possible jamming.

“With this online tool, anyone interested can now see where jamming is affecting satellites in space,” says Kian Bostani Nezhad, scientist and PhD student at DTU Space and Centre for Security DTU, who led the development of the SAT-JAM map.
He is also the lead author of the scientific paper on the subject recently presented at the Advanced Maui Optical and Space Surveillance Technologies Conference 2026 (AMOS).

“Most people see GPS jamming as a problem for airplanes and ships. Few would imagine that it can also reach and disrupt a lot of satellites in space. Although satellite operators are very likely aware of it, because their own spacecraft record the interference, it is rarely discussed publicly,” says Kian Bostani Nezhad.

The map is based on navigation data from different spacecraft, which have been processed to show where satellites experience interference with the navigation signals they use to determine their position.
Satellites in low Earth orbit, about 400 to 600 kilometres above Earth, commonly determine their position in orbit using signals from navigation satellites flying much higher, including the American GPS and European Galileo systems.

Together, these satellite navigation systems are known as Global Navigation Satellite Systems, or GNSS. Russia and China have developed similar systems.

Jamming is surprisingly easy
Over large parts of Europe, jamming from the ground can deteriorate these signals before low-orbit satellites receive them. The navigation signals are already weak when they reach a receiver on a satellite in low Earth orbit. Therefore,ex strong radio interference transmitted from the ground can overwhelm them.

SAT-JAM shows extensive interference over Europe, particularly eastern Europe, but also other parts of the continent.
According to the researchers, part of the geographical pattern is consistent with jamming from a ground-based source capable of affecting this region.
GPS jamming has also caused problems for civilian aircraft and ships in the region in recent years. Satellites in space can now be added to the list.

“It is actually surprisingly easy to jam a satellite, as there are no obstacles between the ground and the satellite. On the ground, jamming can be more difficult because of the topography, buildings and vegetation,” says Kian Bostani Nezhad.

He adds that the map also reveals interference with satellites in other parts of the world, including areas of South-East Asia.
However, SAT-JAM only shows where over Earth the interference is being felt by satellites, and cannot by itself determine the exact interference source or whether the interference is deliberate.

Potential harm to civilian infrastructure
Severe GNSS interference can cause problems for satellites that support everyday life, from weather forecasts and maps to communications, disaster monitoring and security-related uses that are increasingly important for Europe.

”We have observed cases in the data we’ve collected where spacecraft temporarily lose the accurate position information supplied by their GNSS receivers when over Europe,” says Kian Bostani Nezhad.
”This matters for applications that rely on precise positioning. For example, Earth observation satellites need to know exactly where their images were taken, while some communications satellites need accurate position information to point their antennas correctly. So there is a potential for harm here”.

Facts:
SAT-JAM uses publicly available data from the EU’s Copernicus Sentinel satellites to map where GNSS interference is detected and how frequently it occurs. The map covers a rolling 40-day period and is updated as new observations become available.

Explore SAT-JAM: www.sat-jam.com