Why hasn't Russia disabled the key tool that helps Ukrainian weapons hit their targets?

GPS is helping Ukraine hit more targets

The damage to the strategically located Antonovsky Bridge in Kherson, a city in southern Ukraine, showed the power of a precision strike. Traffic on the bridge, one of two main routes into and out of the city across the Dnipro River, was blocked on July 27 following the Ukrainian offensive, as Kiev struggled to retake Kherson.

Illustration: Alamy

The Ukrainian military attacked the position with missiles launched from the US-supplied HIMARS rocket artillery system, which relies on the global positioning system (GPS) to find its target. GPS is a powerful tool of war, but it can be easily disabled by Russia. What is stopping Russia from blocking the GPS system in Ukraine?

The NavStar Global Positioning System was developed by the US Air Force in the 1970s. It was the first system to provide precise positioning anywhere on Earth. GPS receivers receive signals from satellites and decode them using trigonometric calculations. GPS can operate in all weather, space and temperature conditions.

GPS-guided munitions have all but replaced unguided bombs in the US arsenal. Many other weapons systems, from missiles to artillery shells, are also equipped with GPS guidance. Much of Ukraine’s Soviet-era arsenal does not have such advanced technology. However, the US and its allies are increasingly supplying Ukraine with GPS-guided missiles, which, while expensive, are virtually guaranteed to hit fixed, known targets.

In reality, the GPS system is vulnerable to attack. Global Positioning System satellites orbit the Earth at a distance of 20,000 kilometers (12,500 miles), but their transmitters are only as powerful as a car's headlights. Weak signals can be drowned out by radio transmitters operating at the same wavelength. Some transmitters are harder to jam than others. Military GPS receivers often use "M-codes," which are signals for military use only. Some receivers have filters that separate the signals from background noise and directional antennas that select only signals from satellites.

US weapons, such as the HIMARS rocket, also have a backup inertial guidance system that kicks in if GPS fails to guide the missile.

Why Russia hasn't disabled GPS yet, even though it has the capability

Still, Dana Goward, president of the Resilient Navigation and Timing Foundation and a former member of the US government’s GPS advisory board, said Russia could take more steps to prevent precision strikes from Ukraine. He said Russia has not yet launched GPS jamming to avoid a possible conflict with NATO.

First, a high-intensity jamming device could make it an easy target to detect. Additionally, it is possible that some Russian forces themselves are using GPS instead of GLONASS, Russia's own global navigation satellite system similar to GPS. The Kremlin therefore refrains from jamming GPS to avoid disrupting its own forces.

Russia has the capability to completely disable the GPS satellite system, but it is unlikely that it would take such a drastic step just to thwart Ukrainian attacks. An attack on GPS could be seen as an attack on the United States, risking drawing NATO into the conflict.

In fact, to counter the threat, the US has long been developing alternatives to satellite navigation technology. In June 2022, Washington tested a system called RATS on a B-2 bomber. Most of these systems use onboard radar to find a precise location by comparing the ground below to a map, known as terrain contour matching, or TERCOM. This is a guidance system used primarily by cruise missiles for decades.

If Ukraine continues to receive more GPS-guided rockets from the US and UK, the West believes Russia may step up its efforts to jam GPS systems. However, they say that the satellite-guided munitions Ukraine has so far are hitting their targets with impressive accuracy.

Kieu Anh