Satellite navigation is more vulnerable than ever: why PNT resilience is becoming increasingly critical

Satellite navigation has become an essential part of our modern infrastructure. It’s easy to think of it as primarily a technology that sits in our phones and car navigation systems, but the positioning, navigation and timing (PNT) information provided by satellite navigation systems (GNSS) are critical to everything from transport and telecommunications to energy networks and financial systems. A report by London Economics in 2021 put the cost to the UK economy of a failure of satellite navigation services over 24 hours at £1.42Bn. Yet, because they usually work seamlessly in the background, we rarely consider how dependent we have become on them.

A growing threat to GNSS

We live in a dangerous world. Wherever there is a dependence, it is safe to assume there will be threats, and if there is both dependence and threat then there is risk. At GMV, we are experts in helping organizations manage PNT risk, and that means understanding both the dependance and the threats. 

One of the most important threats to GNSS is interference. Whether it’s jamming, spoofing, or just background noise, radio signals can interfere with the way that GNSS equipment processes signals and generates position and time information. GNSS interference has been in the news a lot in recent years as it has become a constant threat in Eastern Europe and the Middle East. A fascinating report published by the Ops Group in 2024 documented the increasing occurrences of spoofing in aircraft and the various ways in which it can impact the aircraft’s systems. 

What the 2019 events revealed

GMV has been monitoring GNSS interference for over 10 years and has seen many millions of interference events both large and small. But in 2019, our monitoring units deployed across Europe detected particularly unusual events that are helping us better understand an increasingly complex radio-frequency threat environment. 

What made these events particularly interesting was seeing them occur almost simultaneously in numerous detectors located thousands of kilometers apart. We had never seen this before and it pointed to something new. The geographical distance between them suggested one of three things: a malfunction in our systems; a network of transmitters across Europe all transmitting simultaneously; or a source that was not terrestrial. Well, when you have eliminated the impossible whatever remains however improbable must be the truth. We checked our equipment, we ruled out terrestrial emitters, and so we knew we had interference from space.

Subsequent research by the University of Texas, backed up by our own independent findings, has traced the source to satellites in the Russian EKS constellation, designed to provide early warning of ballistic missile launches. The evidence suggests that these transmissions were intentional and occurred within frequencies used by GNSS systems. Whether or not their purpose was malicious we can’t say for sure, nor do we know whether the low power interference that we’ve seen to date is the limit of what EKS can transmit, and the classified nature of the EKS program means we may never know. But to date we have no evidence that these signals have ever caused disruption to GNSS receivers. We are just left with a threat, one of many, and a risk.

From threat awareness to risk management

The knowledge  is critical to making informed decisions about managing the risk. If we can understand the threat and understand the impact, then we can determine the most effective and efficient ways to mitigate the risk. That might be install backups, monitor for threats, introduce training and procedures, buy insurance, … it might legitimately be do nothing at all. Knowledge is power.

None of this is new; modern risk management theory emerged in the 1950s, but is an extension and formalization of natural human intuition. But, surprisingly, it is new for PNT. For so long, the threats have been ignored and the risks have grown. Ignorance is bliss, as they say, but for many it’s now becoming a problem. Last year the Royal Institute of Navigation, with support from GMV and others, published its PNT resilience best practices and checklist which gives a first simple set of steps for organizations to follow. 

Building PNT resilience

For most organizations, going beyond the first steps will need help from experts. That’s where companies like GMV come in. We have a huge wealth of experience and knowledge in threats and dependencies, as well as the tools to dig deeper and assess how threats could affect critical systems and to understand complex system-of-system behaviors. And we have a deep understanding of the technologies, architectures, processes, training, and monitoring that will help to mitigate those threats.

This is what PNT resilience is ultimately about: not assuming that satellite navigation will always be available, but preparing systems to operate safely and reliably when it is not. 

And through informed PNT risk management we want to make sure that position and timing information enables businesses and governments to thrive and excel, and mitigation does not become an unnecessary cost and burden.

The interference events we have been studying since 2019 are another reminder of why this matters. As more sectors become dependent on accurate positioning and timing, PNT resilience must increasingly be treated as a fundamental component of good management in national infrastructure.

The question is no longer whether GNSS interference will occur. It is whether we are prepared for it.

Author: Richard Bowden