Pulsar 0, a prototype navigation satellite from California startup Xona Space Systems — which is also building a 300 satellite commercial GPS alternative called Pulsar — found GPS interference far more widespread than its builders expected.
The Global Positioning System signal that times stock trades, synchronizes power grids, and guides aircraft has been under sustained attack from ground-based jammers for years. This week, a small experimental satellite called Pulsar-0 produced the first space-based map of how widespread that interference has become, and the engineers behind the project said the picture is worse than they expected.
Pulsar-0, built by the San Bruno, California startup Xona Space Systems, spent the last several months listening to GPS signals from an altitude of roughly 310 miles and found jamming and spoofing across Europe and the Middle East at a scale the team had not anticipated. "It's quite a bit more than we expected," the Xona team said of the findings, in a measurement that its operators are now positioning as the leading edge of a much larger effort to rebuild positioning infrastructure from low Earth orbit.
GPS, and the family of global navigation satellite systems it anchors, is widely understood as a way to find a location. That framing misses the more important role the signal plays. The constellation of medium-Earth-orbit satellites that broadcast GPS, Europe's Galileo, China's BeiDou, and Russia's GLONASS also carries a nanosecond-accurate clock signal that power grids use to balance load, that financial exchanges use to time-stamp transactions, and that cellular networks use to coordinate handoffs between towers. When GPS degrades, those systems degrade with it, often invisibly, often in ways that do not show up until something fails.
The Pulsar-0 measurement, reported by Space.com, documented interference in Europe and the Middle East at a scale that, according to the Xona team, "could affect" satellite performance and operational safety well beyond the regions where the jamming originates. That phrasing matters: the team is not claiming global interference or permanent outages, and the data do not show GPS going dark. They do show that positioning, navigation, and timing signals are degraded in the air around the conflict zones and the flight corridors that cross them, and that the degradation is consistent with a five-year campaign of ground-based jamming that has only grown in scope.
Xona Space Systems is not a neutral observer in this picture. The company is one of several startups building a commercial low-Earth-orbit alternative to GPS, with a planned 300-satellite constellation called Pulsar that the company says will be harder to jam than the medium-Earth-orbit GPS constellation by virtue of being closer, broadcasting stronger signals, and existing in numbers too large to take down cheaply with line-of-sight ground jammers. Pulsar-0 is the prototype. The data it just produced are, by design, also the data that justify the larger system.
That overlap is not a reason to discount the measurement. The GPS interference that Pulsar-0 documented is real, the Xona team's surprise at its scale is consistent with reporting from airlines, shipping companies, and energy operators that have logged thousands of jamming incidents over the last several years, and the response architecture being built around it is in orbit. What the overlap does mean is that the framing of the measurement is also, in part, a commercial argument, and a reader weighing the result should know that the company whose satellite produced the data is also the company that wants to sell the fix.
What to watch next: the next Pulsar satellites are scheduled to begin launching in the second half of 2026, with the full 300-satellite constellation targeted for completion by the end of the decade. The first question for the program is whether its signal is, in fact, harder to jam in practice, and whether a constellation of commercial satellites can be operated with the reliability that aviation, finance, and energy demand. The second is whether the incumbents, including the U.S. Air Force, the European Space Agency, and the operators of BeiDou and GLONASS, treat the new commercial layer as a complement or a competitor. The data from Pulsar-0 suggest the threat it was built to respond to is real. The deployment will tell us whether the response is.