The Evolution of PNT

Where are we? What time is it? How do we get there? The foundational need to know our location and time is at the heart of position, navigation, and timing (PNT) infrastructure. For the last half century, PNT and GPS (the US Global Positioning System) have been interchangeable; there are 8 billion GPS receivers in the world – one for every person on Earth - and GPS pervades all aspects of our lives: our location on digital maps and ride-sharing apps, commercial and airline navigation, the timestamp on ATM, credit card and stock transactions, and the timing heartbeat of high-speed digital networks. But there may be a disruption in the GPS hegemony over PNT.   

1974 to 2000 "Drop Five Bombs in the Same Hole" 

There was PNT in the era before GPS, but it was imprecise and required a lot of training. GPS was developed by the US military as an experiment "to drop five bombs in the same hole." Initially it was underfunded and under-supported - until it was launched and the performance exceeded expectations. Then, there was no going back. While it was initially only available for the US military, the readily-available signal attracted hobbyists that developed their own receivers that eventually were offered to the public. But the timing signal also had a commercial value for the early networks that needed a common clock to multiplex their signals, and then digital networks that needed synchronized nodes to efficiently route their data packets. The US military did not like this, and limited access and the quality of the GPS signal. But two Executive Orders - one in 1983 and another in 2000 - finally opened GPS to the wider world. Overnight GPS became an economic engine for the world: its freely available signal spawned over 700 companies and $2 trillion dollars of economic benefit.   

2000 to 2025 Comfort is the Enemy of Progress 

But that ubiquity is also a major problem: we are too reliant on GPS. A signal that is 1000 times weaker than the weakest cell phone signal is a foundation for all of our critical infrastructure, making it an easy target for threats from all angles, even from above (see below). An extended outage of GPS, for any reason, would be catastrophic to our modern world. Our over-reliance on GPS, and the demand for an alternative, was identified a quarter century ago, yet progress on an alternative has been slow. And there isn't interest in improving the civilian signals, which is holding back the improvement needed for future applications like 6G, trusted financial transactions, the quantum internet, efficient data centers and power grids. Therein lies the challenge: GPS is a readily available resource that is so embedded in our infrastructure, our lives, that there is resistance to building an alternative. But change is coming.   

The Future: One-Size-Does-Not-Fit-All 

On June 1, as part of Operation Spiderweb, Ukrainian drones initially used GPS signals to help destroy Russian bombers deep inside Russian territory. Prior to this operation, Russia had been jamming GPS only in conflict zones and around critical infrastructure. Now, they are extending this jamming inside Russia. As noted by an expert at the PNT Leadership Summit, this audacious attack acts as an alarm for governments around the world - and a fundamental change in how we use GPS for our PNT needs. To prevent similar attacks, officials will likely start denying GPS around military and critical infrastructure.

Take the Bullseye off GPS" graphic courtesy of the Resilient Navigation and Timing Foundation (https://rntfnd.org/)

It is likely that, in time, all major urban areas will be GPS dead zones. This may accelerate a movement towards use-case-specific PNT alternatives: space-based navigation and augmentation signals for aviation; sensitive sensors and cameras tied to AI algorithms for position and navigation; hybrid space and terrestrial timing infrastructure for enterprise users; and local PNT signals that can be readily shut off, if necessary. The one-size-fits-all PNT capability provided by GPS needs to evolve to tailored solutions; in this future, PNT will stand for position, navigation, or timing.