Russia can jam GPS. Scientists have proposed alternatives, defense is already using some of them, and over time they may spread to civilian life

Over the past decades, GPS has become so common that we hardly notice its operation. Satellite navigation is needed not only for smartphones and cars. Aviation, shipping, telecommunications, power grids, and even financial markets depend on it.

But the system has a fundamental weakness: the receiver must receive radio signals from satellites. They can be jammed or spoofed so that the device shows the wrong location.

The war in Ukraine has demonstrated how vulnerable satellite navigation can be. Electronic interference has reduced the effectiveness of some GPS-guided weapons, including high-precision Excalibur artillery shells Excalibur and HIMARS missile systems.

But the consequences of GPS jamming are no longer felt only by the military. According to European aviation authorities, about 40% of air traffic in Europe experiences GPS interference. This happens particularly often in Eastern Europe, the Black Sea region, and the eastern Mediterranean. Aircraft may lose satellite signals or receive false coordinates.

Therefore, developers are increasingly proceeding from a simple principle: one must be prepared for GPS not being available when needed. The alternatives were described by the Financial Times.

Quantum sensor

One of the most unusual options is being tested using quantum physics.

In 2024, an experimental flight of a British military aircraft took place over southern England. On board was a device about the size of a suitcase, inside which atoms were cooled to a temperature just a few billionths of a degree above absolute zero.

Cooled almost to absolute zero, atoms react extremely sensitively to acceleration. Lasers make it possible to fix even very small changes in their movement and determine the aircraft's acceleration from them. Knowing the initial coordinates, a computer can calculate how the aircraft's speed and position change, and thus determine its location without GPS.

Ordinary inertial navigation, which uses accelerometers and gyroscopes, determines location in a similar way. But small measurement errors accumulate over time, so the calculated location increasingly deviates from the true one. Quantum sensors allow such measurements to be made much more precisely. At the same time, the system works autonomously, so it cannot be jammed by radio interference like GPS.

For now, however, there is a significant drawback — the price. The estimated cost of the system from the American company Infleqtion is about a million dollars. This is acceptable for an expensive aircraft, ship, or submarine, but not for a cheap drone that can be lost after one flight.

Quantum magnetometer

Another approach involves using quantum magnetometers. These devices allow orientation by the Earth's magnetic field without resorting to satellite signals.

The magnetic field is not uniform everywhere. Small local deviations create a kind of magnetic landscape, by which location can be determined if a sufficiently accurate map is available.

Such a system is being developed by the Canadian startup SBQuantum. Its quantum magnetometer measures small changes in the magnetic field and compares them with a map. Scientists believe that some migratory birds, sea turtles, and whales use a similar principle of orientation in nature.

Developers expect the first generation of the system to be able to determine location with an accuracy of approximately 100 meters throughout the flight. Its estimated cost is about $25,000. Such a price and accuracy make the technology potentially suitable for large drones, aircraft, and autonomous underwater vehicles, but for high-precision missiles and shells, such accuracy is insufficient.

Navigation using cameras

There is also a much simpler way to understand where an aircraft is: look at the ground.

A camera photographs the terrain under the aircraft or drone, and a computer compares the image with pre-loaded maps and satellite images.

Previously, this technology was only available for the most advanced cruise missiles. Now it has become cheap enough to be used on drones as well.

Return of past technologies

In the search for alternatives to GPS, developers are turning not only to new technologies. Systems that existed long before satellite navigation are also becoming sought after again.

The UK, for example, is developing the eLoran system with terrestrial radio transmitters. It derives from the Loran system, which was first used during World War II and later helped ships navigate for a long time.

One of the advantages of eLoran is its powerful ground-based signal. To effectively jam or spoof it, large powerful transmitters are needed, which are easier to detect. In May, the British government allocated 6 million pounds for the further development of eLoran.

Another path is not to abandon satellites altogether, but to use other constellations. Low-Earth orbit satellites, including Iridium and Starlink systems, can provide a stronger signal that is harder to jam.

Not one system, but several

All these options have their advantages and disadvantages. Therefore, instead of looking for one full-fledged replacement for GPS, developers are increasingly trying to combine several navigation methods into one system. If one of them stops working, another can back it up.

For example, the German-American company Auterion is developing systems for combat drones that simultaneously use satellite navigation, inertial sensors, and a downward-facing camera. It continuously compares the terrain image with digital maps, so if there are problems with the satellite signal, the device can navigate in another way. The entire complex increases the cost of the drone by several tens of thousands of dollars.

A similar approach is already used in modern cruise missiles. The latest versions of Tomahawk combine GPS with inertial navigation, terrain-following, and terrain image matching. If one method is unavailable, another can replace it.

And on September 9, American Sandbox AQ demonstrated another combination. Magnetic navigation based on quantum sensors was tested together with visual navigation on a disposable Northrop Grumman attack drone.

Thus, the very approach to navigation is changing. While GPS was previously perceived as a signal that would always be available, now technology is increasingly designed with the expectation that it may not be there when needed.

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