Why GPS could soon become obsolete

GPS works well until it doesn’t. The signal travels from about 12,500 miles up, and by the time it reaches a phone or a cockpit, it’s weak enough that a cheap jammer can wipe it out across a wide area.

Pilots have been dealing with this reality for a while now, especially over parts of the Middle East and Eastern Europe. Shipping faces similar disruptions. Then there are your everyday apps that quietly assume location data is reliable.

Xona Space Systems, a California-based space research and tech company, has a straightforward answer to that. Fly lower. To that end, the brand is building a constellation of 258 satellites called Pulsar, positioned in low-Earth orbit (LEO) rather than the medium orbit GPS uses. Closer means stronger, and Xona claims its signal will be roughly 100 times more powerful than what GPS delivers.

This extra muscle is supposed to get navigation into places it currently can’t reach, including dense downtowns, heavy tree cover, and building interiors. The first six production satellites are set to launch in October, with early service expected in 2027. Once the full constellation is up, Xona says the system will deliver positioning accurate to within a few centimeters anywhere on Earth.

The company already has one satellite in orbit. Launched on a SpaceX Falcon 9 rideshare in June 2025, Pulsar-0 has spent the intervening time running live jamming tests across several countries.

According to Xona, the stronger signal shrinks a jammer’s effective range by 95 percent. On-orbit Software updates have also improved the satellite’s accuracy, cutting the ranging error from about four centimeters down to roughly one and a half, all without anyone touching the hardware.

The original idea, revisited

Interestingly, satellite navigation started in low orbit to begin with. The U.S. Navy’s Transit system, which became operational in 1964, was built on work by Johns Hopkins physicists who had been tracking Sputnik-1 by measuring the Doppler shift in its radio signal.

The physicists soon realized that the math worked both ways. If you know where the satellite is, you can work out where the receiver is. Polaris submarines relied on this transit system to fix their positions ahead of missile launches.

Coverage, however, was a major drawback. With a constellation of just 36 satellites, Transit could only offer a location fix every hour or two, whenever one happened to pass overhead. Good enough for a submarine but useless for anything resembling modern expectations.

GPS solved that problem by moving to a higher orbit, where a similar number of satellites could provide continuous global coverage. Low Earth orbit, by contrast, would require roughly ten times as many satellites to match comparable performance, which for decades made it a non-starter. Then SpaceX drove launch costs down far enough that Starlink became possible, and suddenly a few hundred satellites stopped sounding ridiculous.

Xona isn’t the only company chasing LEO-based navigation. TrustPoint, headquartered in Virginia, is targeting early service in 2027 with plans for 300 satellites of its own, using C-band signals rather than L-band to make jamming and spoofing more difficult.

Xona went the other direction and built Pulsar to work with L1 and L5 receivers, the same bands GPS uses. This decision means much of the existing hardware in the field could pick up Pulsar signals with a firmware update instead of a replacement.

Timing is the other half of the pitch, and likely the source of Xona’s early revenue. Financial markets, telecom networks, and data centers all depend on extremely precise time references, so it’s no surprise that the company has already signed customers for its service. Xona says that it aims to deliver accuracy within 10 nanoseconds, using software-defined techniques rather than the expensive atomic clocks GPS satellites carry.

Zak Kassas, director of the ASPIN Laboratory (Autonomous Systems Perception, Intelligence, & Navigation) at Ohio State University, expects the first set of customers to be predictable enough. We’re taking defense and national security agencies, along with government organizations whose job involves keeping things running when systems fail, many of which are already paying for premium positioning services.

Xona anticipates reaching reliable timing coverage in cities with roughly 16 satellites. Centimeter-level positioning needs four satellites overhead simultaneously, a threshold the company expects to manage in priority regions before the full constellation is finished.

Sources: Xona Space Systems, Aerospacelab, Ohio State University, ION GNSS Proceedings, Ars Technica

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