Skip to content Go to main navigation Go to language selector
Saab Global

Keeping on track with PNT

5 min read

In the fourth episode of series two of the Zero Pressure podcast, Professor Washington Yotto Ochieng tells Helen Sharman why positioning, navigation and timing (PNT) are so important to our everyday lives, and explains the challenges, vulnerabilities and opportunities that we need to respond to so that PNT keeps the world turning. 

Positioning, navigation and timing are vital to our modern world. Without PNT infrastructure such as satellites, we would not be able to accurately orient ourselves or communicate in time. Without PNT the social, financial, commercial and military infrastructures that are critical to our existence would come crashing to a halt, with profoundly costly consequences for all of us.

“PNT underpins life as we know it,” says Professor Washington Yotto Ochieng, Head of Department of Civil and Environmental Engineering and Chair in Positioning and Navigation Systems at Imperial College London.

Professor Ochieng, the main guest on episode four, series two of Dr Helen Sharman’s Zero Pressure podcast, is uniquely well placed to comment. As Senior Security Science Fellow at Imperial’s Institute for Security Science and Technology, he has taken part in various international industrial programmes to develop satellite navigation systems, including the European Galileo constellation, and has been consulted by several governments on critical infrastructure resilience.

Available at your favourite channel:

Spotify - Google Podcasts - Apple Podcasts

Positioning technology provides our critical infrastructure

Professor Ochieng explains that the most common examples of PNT today are the Global Navigation Satellite Systems (GNSS) that govern, among so many other things, communications including telephony, and the synchronising of time to deliver information and services accurately and timeously across the world, for civilian and military applications.

“If you think about financial trading between, say, London and New York City, this demands extremely accurate timing to avoid people losing money,” he explains. “Or consider the transport system, such as the timings of bus or train services – that demands accurate positioning technology to relay the right information at the right time.”

Our mobile phones, the sat navs we have in our vehicles, the electric grid, weapons systems – all of these depend on position and timing to ensure efficiency, accuracy and distribution, as well as integrity and continuity of connection.

“This is the critical infrastructure that underpins governments’ duty for providing for the safety of their people,” says Professor Ochieng.


The consequences of failure

Given the all-encompassing extent that our world depends on GNSS, one of Professor Ochieng’s main concerns is to ensure that we understand the vulnerability of these systems.

“London Economics has calculated that the UK would lose more than £5bn at a minimum for a five-day outage of GNSS,”1 he says, citing a 2017 study.

“In 2019, the US Institute of Standards and Technology has said that the Global Positioning System (GPS, the United States’ Global Navigation Satellite System) has generated $1.4 trillion in economic benefits to the country since the system started in the 1980s.”2

And it’s not just hypothetical. Professor Ochieng points out that in July 2019 the European Galileo system suffered a week-long outage. It was reported at the time that this incident took down all the system’s timing and navigation features, although thankfully the search and rescue functionality remained. Although there are less hi-tech fall-back options, it acts as a warning that worse things could come without the right safeguards.

“Service providers must be thinking: ‘how do we ensure that we do not lose such a fundamental utility? ´”, says Professor Ochieng. “But the level of protection is not yet there. It’s like sleepwalking into the abyss.”

PNT targeting and the key to protecting ourselves

In this time of geopolitical turmoil, Helen Sharman also raises the question of whether these satellite positioning and navigation systems could be targeted by hostile forces.

In fact, Professor Ochieng reveals that what’s known as ‘jamming’, ‘spoofing’ and ‘meaconing’ happen all the time.

Jamming is where an external powerful signal overpowers the power level and signal of the GNSS. Spoofing involves broadcasting a fake signal unknown to the user, in a bid to confuse and mislead them. And meaconing is a blend of the two. Of those, spoofing has already been used by pirates in the Indian Ocean to lead ships to them, and the potential is there for further abuse, although so far cases are limited.

Both Professor Ochieng and another featured guest, Julianna Seuss, research analyst and policy lead on space security in military sciences team for UK’s Royal United Services Institute, are agreed that the way to protect these vital systems is international cooperation, to build in a system of systems approach where the weakness of one system can be augmented by another, to plug the gaps. In that sense, Professor Ochieng says the Galileo model of collaboration is a key example.

And that complementary approach is particularly important with regard to military applications, where the navigation of difficult environments such as underwater or inside buildings demands links with ground-based PNT systems to guarantee continued signal integrity.

“Either directly or indirectly, PNT is a force for good and for saving the planet. If countries can collaborate with this fact in mind, then the world can be a much better place,” says Professor Ochieng, rounding off yet another insightful episode of the Zero Pressure podcast.

How to follow us

This podcast in Imperial College London and Saab’s Zero Pressure series is available on most podcast platforms including Spotify, Google and Apple.

Your questions, comments and suggestions for future discussions are welcome. Follow us on your favourite podcast platform and on Twitter to stay involved!