How GPS, created for war, shaped the modern world — Photo: Getty Images via BBC
In 2017, the crews of several tankers had a disconcerting experience. As they approached their destination, they discovered that they were in two different places at the same time.
Their eyes told them they were arriving at the Russian port of Novorossiysk on the northern coast of the Black Sea.
But the global positioning system showed that, instead of sailing on water, it looked like they were flying through the air.
When they docked, the GPS continued to insist that their ships were on dry land at a nearby airport.
This story was the spark that led economic journalist Katherine Dunn to explore GPS, this technology that places us on a map and creates a representation of the world completely centered on us.
He also gave us a new way of identifying ourselves: a little blue dot that, without instructions or manuals, we learned to recognize as a self.
Soon, it became part of everyday life, not only as a tool to know where a place is and how to get there, but also how long it will take.
If we stop to think, we quickly realize that it is also used for taxis to pick us up or to shop online and, when we broaden the focus, we visualize its role in global logistics, particularly in the transport of people and goods.
But we may miss its role in systems like the synchronization of vast networks—mobile phone towers, banking systems, and electrical grids—where it helps create the kind of fluid communication that we now take for granted.
Its ubiquity extends into areas we might not associate with GPS, from high-risk applications related to financial networks and missiles to precision agriculture and even traffic light coordination.
All this thanks to the constellation of satellites that orbit the Earth and the simultaneous and ultrafast resolution of four unknowns.
That's what Dunn told BBC Mundo. The curiosity aroused by the ship episode led her to research and write Little Blue Dot: How GPS Shaped the Modern World ("The Little Blue Dot: How the GPS Shaped the Modern World", in literal translation), without translation into Portuguese.
Katherine Dunn, on the Greenwich meridian, with her book — Photo: Personal Collection via BBC
BBC Mundo — How does GPS work?
Katherine Dunn — The idea is that, wherever you are, you need to receive the signal from four satellites, because together they are solving four equations: your longitude, your latitude, your altitude — something we often forget, but which matters if you are, for example, on the sixth floor of a building — and a fourth variable, which is time, measured with an accuracy of billionths of a second.
The entire system depends on perfect accuracy in measuring time. And as a byproduct of using time to calculate your location, GPS ends up giving you an atomic pocket clock: It takes the time from atomic clocks traveling on satellites and delivers it, without you even realizing it, to your cell phone or car.
Essentially, it's a computer in space talking to a computer at the receiver, which in turn talks to a computer at a ground station.
The physics behind it are extremely complex, but the general idea is so elegant that this is probably why the system has stood the test of time and become so successful.
BBC Mundo — Why does GPS need to know something as specific as which floor of a building you are on?
Dunn — Because it was designed for airplanes, as a tool for precision bombing.
It has antecedents — many of them also linked to bombing campaigns — but it stems directly from the Vietnam War, when the United States Air Force repeatedly failed to accurately attack the Ho Chi Minh Trail and the bridges used to transport troops and supplies.
Here was the powerful US aviation, unable to hit a bridge in North Vietnam. They needed extreme precision, and in three dimensions, as well as a very high calculation speed, because a plane moves very fast and needs to know its location almost in real time as it crosses the sky.
BBC Mundo — That's why time is such a critical factor. And this is the hardest part to understand for non-physicists.
Dunn — People often say that "GPS works by triangulation", but no: triangulation involves angles; here, it's pure speed.
The system calculates how long it takes for a radio signal to leave the satellite and reach the receiver, and needs to measure this interval with an accuracy of billionths of a second, because the differences that need to be detected are minuscule.
BBC Mundo — Developing GPS required the most advanced technology, from those atomic clocks to rockets, batteries and computers. To maintain it, millions of dollars are needed per year and, even so, it is free: a rarity, especially if we consider that it was born in the United States, the bastion of capitalism.
Dunn — It's curious that, for years, the Pentagon itself didn't give him much value. Only when other countries began to adopt it did they realize that they had in their hands not only a very powerful military tool, but also an industrial, commercial and power tool.
In the late 1990s, after a chance incident that threatened the frequency space used by GPS, the American government understood two things: that if everyone depended on this system, it would be better protected, and that entire industries were being built around it, with the United States manufacturing the receivers.
In part, they recovered this investment in other ways: the system boosted gigantic industries, many of them led by American companies. Big tech companies, for example, rely heavily on location data and are built on a government product, paid for with taxpayer dollars.
BBC Mundo — They actively promoted the adoption of the system by other governments, and many did so willingly, but some were not so happy, right?
Dunn — Europeans began to become uncomfortable with the idea that so much infrastructure depended on a single American product, and from this, in large part, Galileo, the European system of strategic autonomy, emerged.
Today, it is more diverse, although GPS continues to be the dominant system in many industries, even though it is no longer the best of the five that exist — the Chinese one, they say, is by far the most advanced — simply because it is the oldest and many receivers are manufactured with just it in mind.
Aviation, for example, tends to use only GPS, while a phone's chip tends to take advantage of all available constellations at the same time.
The second iPhone model was the introduction of GPS to the general public and marked the moment when it began to become an everyday thing for millions of people — Photo: Getty Images via BBC
BBC Mundo — Who were the first to use GPS outside the military?
Dunn — The first users outside the military were nerds: surveyors and university researchers. Then came very specific specialists and, later, a handful of wealthy nerds who looked for dinosaur fossils or were sailing enthusiasts — a certain type of elite adventurer capable of paying for receivers that, in the beginning, cost around US$100,000, today equivalent to R$514,000.
It was only in the 1980s that the first car with GPS appeared, and it was the Japanese who realized the potential for the automobile industry, in part because Japan had been, in the post-war period, a kind of workshop for the United States and ended up perfecting this technology even more than its creator.
For the rest of the world, if you weren't a fan of technology, engines, mountaineering or navigation, the first step was to have a TomTom or a Garmin in your car.
But the big leap came with the iPhone 3G, the first to incorporate GPS, and Google Maps as a mapping application: it was no longer something that was kept in the car, but something that you carried with you all the time.
BBC Mundo — GPS began to be widely used and replaced the maps that used to tell us where things were, but it turned out that some of them were not exactly where we imagined.
Dunn — It's a crazy idea, isn't it? Today we are used to information corresponding to reality: if it's on the map, it has to be there.
But it wasn't always like that. GPS highlighted these discrepancies and forced them to be corrected.
The Statue of Liberty is a famous example, but it turned out that there were many other things like it, including landing strips displaced several meters from their official coordinates.
What I understood is that absolute precision doesn't exist: it's always about getting as close as possible and continuing to make adjustments.
BBC Mundo — But, if in these cases the GPS helped to reconcile the maps with reality, in others the exact opposite happens, as happened with the crews of those ships in the Russian port of Novorossiysk: their GPS showed that they were on the runway of an airport located tens of kilometers away.
Dunn — It is the first major episode of its kind that is publicly known.
Researchers began to notice that this interference occurred wherever Vladimir Putin was — in fact, he was nearby during the Novorossiysk incident — and also around Russian government buildings, such as the Kremlin or the so-called Putin Palace on the Black Sea.
And then, in a documentary about Russian opponent Alexei Navalny, who is investigating this palace, they saw a scene in which they tried to fly over it with drones, but were unable to get closer.
This is how they realized the connection: the maneuver was intended to prevent drones from approaching, whether to spy or to attack figures in power.
Russian counterintelligence used powerful electronic jamming equipment and transmitted pre-programmed false coordinates to create a mobile, invisible shield around them — Photo: Getty Images via BBC
BBC Mundo — How is this done, technically?
Dunn — This is where the difference between interference and signal falsification comes in.
Interfering is simply muffling the signal: it's as if, while you're saying something, I start shouting. You keep talking, but no one can hear you.
Forgery is more cunning: it is hijacking the signal, as if, suddenly, I took over your voice and said things that you never said or would say.
In these cases, there was a bit of pure interference, but what caused the ships to "appear" at airports was spoofing.
And the reason they chose airport coordinates is that, at that time, most commercial drones were factory configured to change direction or crash if they detected that they were close to an airport, for security reasons.
If they could make the drone believe that Putin's location was an airport, the drone would not be able to get any closer.
Today, for any professional, it is very easy to get around this restriction; in Ukraine, with the current use of drones, this limitation has been completely overcome.
Dunn — It would be possible, yes. It would be extremely disruptive, but the good news is that today there are other alternative systems, so the phone probably wouldn't even be affected.
What causes most fear is not so much the disappearance of the GPS, but that it is manipulated without anyone noticing. Yes, this is scary, because we have much less idea of how the systems would react in this scenario. It's similar to a cyber attack, but analog.
Dunn — From drone warfare and the front lines in Ukraine to what happened in the Strait of Hormuz, you may have seen some of these effects: ships taking strange routes, making senseless turns, or even high-precision American missiles that arrive in Ukraine and suddenly don't work as they should.
BBC Mundo — To finish: I love this image evoked by the title of your book, that of transforming ourselves into a small blue dot on the screen.
Dunn — This title connects to something I thought about a lot while writing: there was this idea of space exploration, of looking at the sky, at the cosmos. However, a lot of what we did was go out just a little bit into space and turn the cameras back on ourselves.
There is something contradictory in the fact that much of this science and physics ended up being put at the service of war — and also, in everyday life, of selling us things and making us spend money.
Although there is also a positive side: much of climate science, for example, arose from these same discoveries. Technology is neither good nor bad in itself; it can be both things at the same time.
