What real-world jamming and spoofing tests tell us about the future of resilient Positioning, Navigation and Timing
For five days in September, the island of Andøya in northern Norway once again became one of the world's most unusual test environments for satellite navigation. At Jammertest 2026, navigation, timing and communication systems were deliberately exposed to controlled GNSS jamming, meaconing and spoofing under real-world conditions. The authorised tests covered both position and time manipulation and were designed to investigate not only whether equipment would lose GNSS, but also how systems would behave when receiving misleading information.
What started only a few years ago as a comparatively specialised field-testing initiative has developed into a major meeting point for the international PNT community. Authorities, research organisations, receiver and antenna manufacturers, application developers and users now come to Andøya to expose their technologies to conditions that are difficult to reproduce completely in a laboratory. The increasing scale of Jammertest reflects a broader development: reliable GNSS can no longer simply be assumed.
But perhaps the more interesting observation from Jammertest 2026 is that the industry's understanding of GNSS resilience itself is changing. The challenge is no longer only to keep a receiver operational when interference occurs. Increasingly, resilient PNT means protecting reception where possible, detecting interference and manipulation, assessing whether position and time can still be trusted, and making this information available to the systems that depend on GNSS.
Resilient PNT is evolving from a component-level challenge into a system-level discipline.
From 2022 to 2026: The Rise of Real-World PNT Testing
The first major Jammertest on Andøya took place in September 2022. Already then, the event offered something that conventional laboratory testing cannot fully reproduce: complete systems could move through genuine over-the-air jamming and spoofing fields while their behaviour was observed and recorded.
One of the participants at that first event was GPSPatron, a hensec technology partner. GPSPatron deployed three GP-Probe TGE2 monitoring stations within the test area and another probe at a nearby reference location. Data was transmitted in real time to GP-Cloud, enabling interference events to be detected, recorded and analysed. According to GPSPatron's published report, its system detected all spoofing scenarios to which it was exposed. The tests also produced some striking observations, including a mobile receiver showing a position displacement of approximately 20 kilometres during one jamming scenario and the detection of unintended spoofing-signal leakage during preparations for another test.
Those experiments demonstrated an important principle at a relatively early stage: interference itself can be valuable information. Knowing that GNSS is being disturbed – and understanding when, where and how – can be just as important as attempting to maintain a navigation solution.
Four years later, this idea is increasingly visible across the PNT community. Jammertest is no longer simply about comparing how long different GNSS receivers retain a position fix. Current test programmes address resilient antennas, receiver-level interference mitigation, spoofing detection, authentication, timing resilience, sensor combinations and the behaviour of complete navigation systems. Kongsberg, for example, used Jammertest 2026 to evaluate different combinations of CRPA antennas and GNSS receivers in its dynamic-positioning reference systems.
Why Real-World Testing Matters
Modern GNSS equipment is extensively evaluated with RF simulators, signal generators and controlled laboratory setups. These environments are essential because tests can be repeated under precisely defined conditions. But the real world introduces additional variables: changing geometry, propagation and reflections, moving platforms, multiple interference sources and interactions between GNSS and other components of the system.
This is why open-air testing has become so valuable. During Jammertest 2026, for example, Kartverket planned to survey the same area from an aircraft both under normal GNSS conditions and during interference, using aerial photography and laser scanning. Known reference points on the ground allow the resulting data to be compared. The experiment is particularly interesting because precise timing is required to associate individual laser measurements with the correct position.
This illustrates a fundamental point: a GNSS receiver can perform extremely well under normal operating conditions and still produce unexpected results when confronted with realistic jamming or spoofing. More importantly, the consequences may propagate beyond the GNSS receiver itself. Position and time are often inputs to other sensors, control systems and databases. A misleading PNT solution can therefore influence an entire processing chain.
For autonomous systems this becomes particularly important. An UAV, UGV or autonomous vessel may combine GNSS with inertial sensors, cameras, LiDAR, radar and other sources of information. GNSS position and time may also be used to georeference the data generated by these sensors.
The relevant question is therefore no longer simply:
Do we still have a GNSS fix?
It increasingly becomes:
Can the system still trust the PNT information it is receiving?
Beyond Position: From GNSS Resilience to Trusted PNT
GNSS is frequently discussed primarily as a positioning technology. Yet the “T” in “PNT” – Time – is equally important. Telecommunications, energy networks, financial systems, data centres, measurement infrastructure and many other applications depend on accurate and trustworthy timing.
Jamming and spoofing also present fundamentally different problems. A jammer attempts to prevent or degrade reception of the extremely weak satellite signals arriving at the Earth's surface. The resulting loss of navigation may be operationally serious, but it is often obvious to the system that GNSS is unavailable.
Spoofing is more subtle. Counterfeit or manipulated signals attempt to convince a receiver that incorrect position or timing information is genuine. A system that recognises the loss of GNSS can switch to alternative sensors or enter an appropriate degraded operating mode. A system confidently operating on a plausible but incorrect position or time presents a much more difficult problem.
The official information for Jammertest 2026 illustrates this distinction particularly well. Norwegian authorities warned that equipment reacts very differently after losing or receiving false position information. Some devices recover automatically when interference ends, others require a restart or even complete removal of power. They also point out that gradual manipulation of position or time can be particularly difficult to recognise because a receiver can first be presented with nearly correct information and then slowly moved away from reality.
This is one reason why resilient PNT increasingly requires several complementary protection mechanisms rather than a single “anti-jamming” feature.
Galileo SAS: A Major Step Against Spoofing
One of the most significant technical milestones of Jammertest 2026 came from Galileo.
On 16 September, five operational Galileo satellites transmitted a new encrypted signal component over Europe for two hours. Receivers at Andøya and at ESA's ESTEC navigation laboratory in the Netherlands successfully used these signals to establish their position. According to ESA and EUSPA, this represented the first real-world civil GNSS position authenticated through both navigation information and ranging measurements using Galileo's upcoming Signal Authentication Service (SAS) together with OSNMA.
The distinction is important. GNSS positioning fundamentally depends on navigation information transmitted by the satellites and on measurements of signal travel time used to determine range. Galileo's Open Service Navigation Message Authentication (OSNMA), operational since 2025, enables compatible receivers to verify that the navigation message originates from Galileo. SAS complements this by authenticating the ranging information itself through an encrypted component of the Galileo E6-C signal.
During the Jammertest demonstration, conventional receivers exposed to spoofing reported false positions, while the SAS receiver detected the attack and maintained a trusted position based on authenticated Galileo signals, according to EUSPA's account of the test. Further SAS testing and validation are planned as Galileo works towards initial service.
This is an important step towards trusted civil PNT, but it also demonstrates why terminology matters:
Jamming resilience is not the same as spoofing resilience – and neither alone guarantees trusted PNT.
Authentication adds another layer to the architecture.
A Layered Approach to Resilient PNT
Taken together, the developments visible at Jammertest increasingly point towards a layered approach.
At the antenna and RF level, resilient antenna technology can reduce the impact of interference before affected signals reach the GNSS receiver. At receiver level, interference detection and mitigation algorithms can recognise abnormal RF conditions and attempt to maintain reliable navigation. Multi-band and multi-constellation reception provides additional diversity, while authentication mechanisms such as Galileo OSNMA and SAS address the question of whether navigation information and ranging signals originate from a trusted source.
Additional sensors can provide independent information for plausibility checks and continued navigation. Above these individual layers sits another increasingly important capability: situational awareness. Interference indicators, signal-quality information, spoofing warnings and integrity information become useful inputs to the complete system rather than remaining hidden inside the GNSS receiver.
This development is also visible in current receiver technology. Septentrio's published results from Jammertest 2025, for example, concluded that effective spoofing protection benefits from several mechanisms working together and highlighted the importance of providing a spoofing status for situational awareness. Its approach combines multi-frequency operation, interference mitigation, anomaly detection and Galileo OSNMA, among other mechanisms.
The implications extend well beyond an individual receiver. A flight controller, navigation computer, timing system or monitoring platform can make better decisions when it not only receives position and time, but also has information about the conditions under which that PNT solution was generated.
From Interference Detection to Interference Intelligence
This broader system perspective also changes the role of interference detection. Traditionally, interference could simply be regarded as something to suppress. Increasingly, however, it is also something to measure, record and understand.
An interference event has characteristics: when it occurred, where it was observed, which frequencies were affected, how strong it was, how long it lasted and, with suitable equipment, potentially where it came from. When such observations are collected over time or across multiple sensors, interference detection begins to become interference intelligence.
A stationary installation can continuously monitor the GNSS environment around critical infrastructure. A distributed network can provide visibility across multiple sites. A moving vehicle, vessel or UAV can combine its position with interference observations and thereby contribute to understanding the spatial characteristics of a disturbance.
This is particularly relevant for autonomous systems. The same platform can simultaneously be a user of PNT and a sensor of the RF environment through which it moves. Instead of treating GNSS interference merely as an internal receiver problem, information about the interference can be made available to flight control, mission systems, logging infrastructure or external monitoring platforms.
For hensec, this development is particularly interesting because it reflects principles that have shaped our work in GNSS resilience and interference detection for several years. GPSPatron's participation in the first major Andøya Jammertest in 2022 is one example: detection, monitoring, logging and analysis of real interference were already central elements of that work.
Today, the broader technology landscape increasingly combines those concepts with resilient antenna technology, advanced receiver-level mitigation, authentication, sensor fusion and system-level monitoring. At hensec, we work with technologies from companies including Calian, Septentrio and GPSPatron, while also developing integrated approaches for resilient navigation and interference awareness.
This does not mean that one architecture fits every application. A stationary timing installation has different requirements from an autonomous UAV; a critical-infrastructure monitoring network faces different challenges from a survey vehicle or research platform.
But the underlying direction is becoming increasingly clear:
Protect where possible. Detect when necessary. Understand what is happening. And ensure that systems relying on PNT know when that information can – or cannot – be trusted.
What Jammertest 2026 Tells Us About the Future
Jammertest 2026 ended on 18 September, but its technical story is not finished. Many participating organisations collected large amounts of data during the five days of testing, and detailed receiver, antenna and system results require time to analyse. It is therefore important to distinguish between already documented technical results and conclusions that will emerge over the coming weeks and months.
The Galileo SAS demonstration is already a concrete and documented milestone. Other manufacturers and participants have described their test programmes and initial observations, while detailed quantitative 2026 results have in many cases not yet been made public. That is normal for an event of this kind: some of the most valuable findings only emerge after large datasets have been analysed and compared.
The longer-term impact may extend beyond this year's participants. Real-world interference captured at events such as Jammertest can potentially help bridge the gap between open-air testing and repeatable laboratory development. That matters because resilient PNT will increasingly depend on both: controlled, repeatable engineering tests and exposure to the complexity of real RF environments.
Perhaps the most important lesson, however, is broader than any individual receiver, antenna or authentication service. The developments seen on Andøya suggest that PNT resilience is becoming a property of the complete system. Maintaining a position fix remains important, but it is only one part of the problem. Systems increasingly need to recognise interference, assess integrity, combine multiple sources of information and communicate uncertainty to the applications that depend on PNT.
And there is another aspect of Jammertest that deserves recognition. Creating an environment in which GNSS can deliberately be jammed and spoofed at meaningful levels is technically, operationally and legally difficult. Bringing authorities, researchers, GNSS manufacturers, antenna specialists, application developers and users together in such an environment is an achievement in itself. Jammertest provides a rare opportunity for systems to fail safely, unexpected behaviour to be investigated and knowledge to be shared across organisational boundaries.
A sincere thank you to the organisers, authorities, engineers, researchers and participating companies who made Jammertest 2026 possible. Bringing such a diverse community together to test, learn and improve under realistic conditions should not be taken for granted.
As our dependence on satellite-based positioning, navigation and timing continues to grow, this combination of technical innovation, real-world testing and open collaboration will be essential to making PNT more resilient for everyone.
