Recent GPS disruptions across the Baltic Sea region are forcing aviation and defense sectors to prepare for unreliable satellite navigation, an Estonian researcher warns.
Tallinn University of Technology (Taltech) senior lecturer Ivo Muursepp explained that GPS interference is often described using a single general term, although two distinct technologies must be distinguished: jamming and spoofing.
“Jamming essentially means shouting over the real signal. Spoofing is a bit more complex – the device is fed a false location,” Muursepp said.
Spoofing refers to a situation where an aircraft or drone does not completely lose its signal but instead receives incorrect coordinates, causing it to move along an unintended trajectory. This makes GPS interference particularly problematic in a military context.
International media had recently reported an incident in which the GPS signal of a British Defense Minister’s aircraft traveling from Estonia to the United Kingdom was allegedly disrupted. At the same time, attention has been drawn to why drones linked to the war in Ukraine occasionally end up in the airspace of Russia’s neighbors.
Data collected from aircraft on GPS disruptions shows a clear pattern. While most of Western Europe and North America appear almost problem-free on disruption maps, extensive yellow and red areas surround Russia’s border regions. Red marks areas where more than 10% of aircraft passing through within the past 24 hours have detected GPS interference.
The areas around Estonia and Finland, as well as the Kaliningrad region, fall into this category. According to Muursepp, this does not necessarily indicate a single, highly powerful jamming system, but rather a network of multiple devices.
“Right across the border there are quite a few of these jammers. Allegedly, there is a fairly large network of smaller jammers installed, for example, in mobile communications towers. Each of them can cover a radius of about 25 kilometers,” Muursepp said.
The main purpose of such systems is to protect strategic sites in Russia from drone attacks. As Ukraine has targeted facilities deeper within Russian territory during the war, disrupting navigation has become a key defensive measure.
GPS satellites orbit at an altitude of about 20,000 kilometers (roughly 12,400 miles) above the Earth. Because of this long distance, the satellite signal reaches the ground relatively weak – making it easier to interfere with.
According to Muursepp, jamming devices do not necessarily have to be highly complex or massive. Smaller GPS jammers can be built from fairly compact components and can even be used as portable devices on a limited scale. In Estonia, the use of such devices is generally prohibited, but the technology itself is neither new nor difficult to obtain.
He cited programmable radio devices as an example – equipment whose function could be changed using software. The same device can operate, for instance, as a radio, a cellular base station, or a GPS jammer.
“With a small device like that, you might disrupt signals within tens or a few hundred meters. For effects over hundreds of kilometers, you need larger systems and more power,” Muursepp explained.
Several technologies are used to counter GPS interference. Aircraft, for example, are equipped with inertial navigation systems that calculate position based on movement and do not depend on satellite signals. Devices can also be developed to reduce the impact of jamming or filter out interference. However, such solutions are expensive and have not been necessary everywhere until now.
Physics also imposes limitations. Radio waves do not propagate indefinitely, and their effects are reduced by factors such as the curvature of the Earth and physical obstacles. The farther one wants a jamming system’s effect to extend, the higher the equipment must be placed and the greater its power must be.
According to Muursepp, it must be acknowledged that 100% protection is not achievable. As with cyberattacks or air defense, a certain level of risk will always remain. This means that aviation, the defense sector, and critical infrastructure must increasingly prepare for situations where satellite navigation may not always be reliable – and where alternative systems become the standard rather than the exception. (ERR)