Jammertest Reveals How GNSS Attacks Could Disrupt Digital Systems
Swan.my.id - Engineers and officials gathered on Norway’s remote Andøya island to test how GNSS attacks could disrupt the timing and positioning systems that support modern infrastructure.
Known as Jammertest, the annual event uses controlled satellite-signal interference to examine how receivers in aircraft, vehicles, industrial equipment and other systems respond. The goal is to identify weaknesses before real-world attacks expose them.
Harald Hauglin, chief engineer of time and frequency metrology at the Norwegian Metrology Service, is among the specialists involved. The event brings together engineers, physicists, government officials and commercial companies in an open testing environment near the Arctic Circle.
Why GNSS attacks threaten more than navigation
Global Navigation Satellite Systems, including GPS, are widely associated with navigation. However, satellites also provide highly accurate time signals. That timing supports power grids, telecommunications networks, stock markets, transit services and other digital infrastructure.
This dependence creates a potential weakness. Satellite signals are relatively weak and can be overwhelmed by stronger transmissions. Attackers can also manipulate the signals, causing receivers to accept false information about their location or the current time.
Jammertest examines both major forms of interference. Jamming blocks or overwhelms the signal until the service becomes unavailable. Spoofing, meanwhile, hijacks the signal by presenting false location or timing data to a receiver.
Jammertest simulates disruption in the Arctic
The Norwegian event takes place in Bleik, a village on Andøya, around 300 kilometres north of the Arctic Circle. Organisers model the exercise on open technology hackathons, allowing participants to observe tests and share results.
During the 2024 event, staged interference affected test flights involving a Norwegian rescue helicopter and a small aircraft flown by a Eurocontrol pilot. Their tracking displays showed strange patterns that did not match the aircraft’s actual movements.
In another test, engineers gradually increased the power of a spoofing signal. A marker representing their location slowly moved away from the real position and appeared to travel into the Norwegian Sea.
The effects on time were less visible but equally important. Engineers compared a GNSS-synchronised clock with an uninterrupted reference delivered through fibre-optic cables from a receiver protected on the other side of a mountain. This allowed them to measure how far the affected clock drifted from accurate time.
Extended jamming and silent spoofing
One major risk is extended jamming. If GNSS disappears for long enough, backup timing systems may eventually lose synchronisation. The consequences could spread across interconnected digital networks.
The severity would depend partly on the backup infrastructure available. Land-based clocks and fibre-optic connections can provide precise timing, but installing and maintaining them requires significant investment.
A more subtle threat involves slow, sophisticated spoofing. If systems accept false timing without detecting it, backup mechanisms may not activate. This could gradually move digital systems away from reality while concealing the disruption.
Interference has become a growing concern since Russia’s full-scale invasion of Ukraine. Aviation has experienced some of the clearest effects, while transport authorities have reported increasingly frequent disruptions in some areas.
No single replacement for satellite timing
Alternative technologies include fibre-optic networks, atomic reference clocks and precision timing systems such as White Rabbit, developed at CERN. These approaches can be more difficult to manipulate than satellite signals.
However, specialists caution that no single alternative can provide every service currently supported by GNSS. Dana Goward of the Resilient Timing and Navigation Foundation has argued that resilience requires a combination of systems rather than one universal replacement.
That principle explains the purpose of Jammertest. By openly testing receivers and sharing results, participants can measure how long critical services remain stable and determine where stronger safeguards are needed. The exercise treats time and location not as background conveniences, but as essential parts of digital security.
