Smartphone maps, delivery trackers and aircraft navigation all depend on satellite positioning, but the U.S. Global Positioning System (GPS) is just one member of a larger family called global navigation satellite systems (GNSS). Four full global constellations—GPS, Russia’s GLONASS, Europe’s Galileo and China’s BeiDou—circle the globe, guiding civilian travel and commerce while also underpinning modern military operations.
How GNSS finds you
Satellite navigation works by measuring time. GNSS satellites carry ultra-precise atomic clocks and continuously broadcast two things: their exact orbital coordinates and the precise moment the transmission left the satellite. A receiver on the ground—whether in a phone, car, ship or missile—picks up signals from several satellites and calculates its position by comparing the timestamps. At least four satellite signals are needed to solve for three spatial coordinates and the receiver’s clock offset.
The method is fast and typically very accurate, which explains how deeply GNSS is embedded in transportation, finance, telco networks and more. But the signals arriving at Earth are extremely weak, so nearby radio interference—accidental or intentional—can easily disrupt reception. Experts warn that while leaders may be aware of this vulnerability, awareness does not always lead to sufficient protective measures.
Multiple constellations and regional systems
GPS was the first system to reach full global coverage. GLONASS followed, and in the 2000s the EU launched Galileo while China expanded BeiDou into a global service. All four are broadly similar and “dual-use,” serving civilian and military needs. Their satellites occupy comparable medium Earth orbits, though some systems use additional orbital slots to improve regional performance. Many consumer devices now combine signals from two or more constellations to improve accuracy and availability. Separately, countries such as Japan and India operate regional augmentation systems that do not provide worldwide coverage but enhance performance locally.
GNSS as a target in conflict
Modern militaries use GNSS for logistics, mapping, weapon guidance and drone control. That reliance makes satellite navigation an attractive target. Electronic warfare techniques fall into two main categories: jamming and spoofing. Jamming drowns out legitimate signals, while spoofing feeds false timing or position data to receivers. Jamming is relatively crude but effective; spoofing is harder technically but can produce much more dangerous outcomes, such as making a receiver report wildly incorrect speeds or locations.
Real incidents include attempts to obscure vessel movements, spoofing that diverted ships into other countries’ waters and reported cases where aircraft or vehicles were given false locations. Conflicts such as the Russia–Ukraine war have shown jamming and spoofing in action.
Building resilience
Some states, notably Russia and China, run terrestrial backup systems that can supplement satellite signals, giving them an advantage where ground networks are part of national defense plans. No single fix eliminates GNSS vulnerability; responses combine tactics: locating and neutralizing jammers in wartime, hardening receivers, using multiple constellations, integrating inertial navigation and developing terrestrial timing and navigation alternatives. Despite these measures, the convenience and ubiquity of GNSS mean it will remain indispensable—and contested—on and off the battlefield.