"Vulnerable" satellites rule the world – and its wars

Whenever you use a map on your smartphone or, for example, track the movement of a delivery vehicle in an app – you are using GPS.

What many people don't realize is that GPS – the US Global Positioning System – is just one part of a larger family known as Global Navigation Satellite Systems (GNSS).

Four global satellite systems orbit the Earth. They guide planes, ships, cars and trucks along their desired route, or tourists looking for a restaurant, hotel or other location. But these satellites also play a key role in wars.

How do satellites determine your location?

Essentially, satellite navigation is a matter of timing. GNSS satellites have extremely precise, atomic clocks and constantly broadcast two key pieces of information: their exact position in orbit and the exact moment the signal was sent.

Meanwhile, on planet Earth, receivers – like your smartphone, car, but also an airplane or ship – receive these signals and use them to determine their exact position.

They do this using signals from four satellites that provide latitude, longitude, and altitude data – plus one additional signal to mitigate, or correct, time offsets.

GNSS technology is very precise and fast. And deeply integrated into everyday life. But it also has a hidden vulnerability.

"Global navigation satellite system signals are quite vulnerable," Dan Howard, president of the US Foundation for Resilient Navigation and Weather, tells DW.

"They are extremely weak, which means that any radio interference on their frequency, whether accidental or intentional, can disrupt reception. I'm sure people in all governments understand this problem. The challenge is how to ensure that leadership understands this and acts to reduce the risk," Howard points out.

Four global navigation powers: USA, Russia, Europe, China

The first two global navigation systems were developed in the 1970s, during the Cold War between the US and the then Soviet Union.

The United States developed GPS, which became the first satellite navigation network with global coverage. It is the most widely used navigation system in the world.

Around the same time, the Soviet Union developed GLONASS, which was later taken over by Russia.

Then, in the early 2000s, the European Union decided that relying solely on GPS left Europe too dependent on American strategic infrastructure, so it began developing Galileo.

The BeiDou system developed by China is the newest of the four. Like the European Union, Chinese military planners have wanted to reduce reliance on the US GPS.

Designed for civilian and military purposes

The four systems are very similar and have a “dual purpose” – they are designed for both civilian and military purposes.

“GPS, GLONASS and Galileo all use very similar orbits, with a similar number of satellites at altitudes of around 19.000 to 23.000 kilometres,” explains Malcolm McDonald, professor of satellite engineering at the University of Glasgow’s Stretchclyde. “BeiDou additionally uses a higher orbit to provide better coverage over Asia.”

Each system can cover any point on Earth at any time, even if it's something as small as your wristwatch.

"Most devices use multiple constellations [of satellites]. It depends on the device – for example, my smartwatch can use both GPS and GLONASS. And I can tell it to use one or both."

Japan and India operate similar systems, but they do not cover the entire planet, providing only regional navigation data.

Global navigation systems at war

Militaries around the world are increasingly dependent on satellite navigation for logistics, route mapping, and operational planning.

They are also used to guide weapons, including cruise missiles and so-called smart bombs. Armies also use navigation satellites to control drones.

But that made satellites targets.

In conflicts such as the Russia-Ukraine war, both sides use electronic warfare techniques such as "jamming" and "spoofing." These are used to disrupt satellite navigation signals or to trick GPS systems on the ground.

"Faking" is more difficult than "disrupting" and allows you to confuse your opponent.

"Your navigation system may show you are traveling at 400 knots and leaving Helsinki airport, when in reality you are in a car traveling at 120 kilometers per hour outside Berlin," explains Thomas Whittington, an electronic warfare analyst at the United Kingdom's Royal Defence Institute.

This technique can be used to hide the location of, for example, a tanker from Russia's so-called "shadow fleet" that is trying to pass through a certain region unnoticed.

"It has also been used to introduce small errors in a ship's position as it passes through the Strait of Hormuz, which can cause the ship to inadvertently enter a country's territorial waters, allowing that country to stop it and force it to dock for illegal entry," says McDonald.

Howard suggests that this could be an even greater threat to Europe and the US than to Russia and China – because Russia and China have “domestic, ground-based systems that complement GNSS or serve as an alternative to GNSS,” while the West does not.

And "frustratingly," Whittington says, there is no technology that effectively solves the problem of GNSS jamming.

There are attempts to develop technological alternatives to GNSS, but for now, he adds, one of the "most practical" options in war is to "find the jammer and destroy it."