Defence Timing & Synchronisation: What Jammertest 2026 Tells Us About GNSS Resilience

What happens when a defence system does not lose its timing signal, but instead receives a convincing false one?

That was one of the challenges explored at Jammertest 2026, which took place on Andøya, Norway, from 14–18 September.

Described by its organisers as the world’s largest open GNSS resilience test, Jammertest deliberately exposes technology to GNSS jamming, meaconing and spoofing. Crucially, the 2026 programme included spoofing of both position and time.

For defence organisations, that highlights an important point: GNSS resilience is not only a navigation problem. It is a timing and synchronisation problem too.

Why timing matters in defence

Positioning, Navigation and Timing (PNT) supports some of the fundamental systems behind modern defence operations, from navigation and secure communications to targeting, networks and distributed infrastructure.

The UK Government describes PNT as a critical enabler for defence operations and recognises that modern operating environments face increasing risks from GNSS jamming and spoofing.

When systems across different locations need to operate from a common reference, the ability to maintain accurate, dependable and resilient time becomes essential.

Jamming and spoofing create different timing risks

GNSS jamming interferes with or blocks the satellite signal. A well-designed system can detect the loss of its reference and respond through redundancy, alternative sources or holdover.

GNSS spoofing introduces another challenge. Rather than removing the signal, a false signal attempts to convince the receiver that incorrect information is genuine.

That creates an important question for defence timing:

Can your systems identify when the timing reference they are receiving should no longer be trusted?

This is why resilient defence PNT needs to go beyond simply maintaining access to GNSS.

Building resilient defence timing beyond GNSS

The answer is not necessarily to remove GNSS. It is to prevent a single timing source from becoming a single point of failure.

A resilient timing architecture can combine technologies and controls such as multi-constellation GNSS, alternative timing references, high-performance oscillators, holdover, resilient distribution, monitoring and defined failover behaviour.

The UK is already moving towards this layered approach. Government plans for greater PNT resilience include terrestrial timing, improved GNSS resilience, holdover clocks and alternative technologies, while the Ministry of Defence is developing enhanced Long-Range Navigation (eLoran) capability for environments where satellite navigation is blocked or manipulated.

Resilience needs to be tested before it is needed

Jammertest is valuable because it creates conditions organisations hope they will never experience operationally.

For defence infrastructure, the important questions should already have answers:

• What happens when GNSS is lost?
• How long can accurate time be maintained in holdover?
• Can anomalous or manipulated timing be detected?
• What alternative timing sources are available?
• How does the wider network respond during failover?

These are questions that should be addressed during architecture design, testing and validation, rather than during an operational GNSS disruption.

From accurate timing to assured timing

Jammertest 2026 is another reminder that modern defence networks need to consider not only whether accurate time is available, but whether that time can be trusted, maintained and distributed when normal conditions disappear.

At edgeTime, we help organisations understand their timing dependencies and build resilient timing and synchronisation architectures around critical operational requirements.

Because losing time is one problem. Trusting false time is another.