New navigation satellites in low Earth orbit could provide 100 times stronger signal strength compared to GPS and other global navigation satellite systems operating from higher orbital altitudes—enabling greater location accuracy within dense cities, under thick foliage, and even inside buildings. Such signals would also likely prove more resilient to interference at a time when commercial flights, maritime shipping, and even various smartphone apps face increasingly widespread disruption from GPS jamming.
That vision may start to take shape when the first six production satellites of California-based Xona Space Systems are scheduled to launch in October 2026, with early service starting in 2027. Once the full constellation of 258 Pulsar satellites has been launched in the following years, Xona claims that customers will be able to accurately pinpoint their locations anywhere on Earth to within several centimeters.
“That added power means that we can get into that indoor environment that GPS can’t get to today,” Adrien Perkins, co-founder and VP of engineering at Xona Space Systems, told Ars. “Our higher power allows you to get into those jamming environments a lot further than you would with GPS by itself.”
Xona has already launched its first satellite, called Pulsar-0, aboard a SpaceX Falcon 9 rocket rideshare mission on July 1, 2025. The Pulsar-0 satellite has participated in multiple “live-sky jamming tests across multiple countries” to show how having signals 100 times stronger than GPS can help to reduce a jammer’s effective area by 95 percent, according to an Xona blog post. The company also tested an anti-spoof watermark built into Pulsar signals to help receivers authenticate the satellite signals, and used software updates to improve the initial satellite’s “native positioning accuracy” from a 4.2-centimeter ranging error to 1.5-centimeter accuracy.
Like other global navigation satellite systems that deliver positioning, navigation, and timing (PNT) services, Pulsar satellites could also start providing intermittent timing signals to customers in mid-latitude regions following the launch of the six production satellites in October. Xona has already signed up several precision-timing customers to use Pulsar satellite signals in timing and synchronization services for financial markets, telecommunications, data centers, and transportation systems.
Xona expects its satellites to eventually deliver a timing reference accurate to within 10 nanoseconds. But unlike GPS satellites that carry expensive atomic clocks for accurate timekeeping, Pulsar satellites would rely on a much cheaper software-based solution for precision timing.
The Pulsar timing services would become more persistent and available in urban environments once the constellation grows to about 16 satellites in orbit, enabling at least one satellite to be in view on a regular basis, according to Xona. The company also described centimeter-level positioning capability as becoming possible with four Pulsar satellites in view over a region, which it expects to accomplish for “priority regions” before the full constellation is completed.
The first customers for Xona and other companies planning satellite navigation systems in low Earth orbit (LEO) will likely be “organizations that place an exceptionally high value on availability, resilience, integrity, authentication, and precision, and are already accustomed to paying for premium PNT services,” Zak Kassas, director of the Autonomous Systems Perception, Intelligence, and Navigation (ASPIN) Laboratory at The Ohio State University, told Ars. He suggested that such customers would be “defense and national security users and government agencies responsible for resilience.”
Using satellites in LEO to deliver location and timekeeping services is “both a blessing and a curse,” Kassas explained in his column for Inside GNSS. The blessing is that LEO satellites can provide stronger signals to ground receivers by operating closer to Earth, and their relatively fast movements across the sky can be measured in ways that provide additional information useful for geolocation and navigation on Earth.
The curse is that hundreds of LEO satellites are required to reliably provide near-instantaneous location and timing services across the entire world. The prospect of deploying so many satellites is no longer daunting since the advent of lower-cost rocket launches driven by SpaceX, which has enabled the growing megaconstellations with thousands of satellites such as Starlink. But it represented a serious constraint during the US military’s deployment of the world’s first satellite navigation system called Transit in the 1960s.
Helping the Navy’s Silent Service
Before GPS, there was Transit. The idea for the Transit satellite system began with physicists at Johns Hopkins University’s Applied Physics Laboratory figuring out how to calculate the orbit of the Soviet Union’s Sputnik-1, which had become the world’s first artificial satellite. Their work relied on calculating the Doppler shift—the change in observed signal frequency—of radio signals coming from Sputnik as it passed overhead. But additional discussions led to the realization that the Doppler shift from a satellite with a known position could also be used to calculate the location of a signal receiver on Earth.
That paved the way for prototype satellite launches starting in 1959 and the operational start of the Transit satellite navigation system in 1964. With ground stations tracking satellite orbits and calculating their positions, the Transit system was designed to allow the US Navy’s Polaris ballistic missile submarines to pinpoint their own locations anywhere in the world. Navigators aboard a submarine or ship could determine their own location by measuring the Doppler shift of a Transit satellite passing overhead while also receiving the satellite’s pre-calculated orbital and location data as a transmission.
However, the full constellation of just 36 operational satellites meant that Transit could only provide location-fixing services every hour or two at best whenever a satellite appeared over the horizon. That was good enough for the system’s main purpose of helping US submarines calculate their own locations as a foundation for making the necessary missile launch calculations to strike their targets. But it would seem like an eternity to modern-day sensibilities accustomed to getting accurate location information in real time.
Transit eventually gave way to the rise of GPS and other global navigation satellite systems that operate from medium Earth orbits, where they can use a similar number of satellites to provide near-instantaneous PNT services across the world. Unlike the Transit system’s use of Doppler shifts, GPS provides location information by using a combination of signals from four or more satellites to
To replicate the performance of GPS, a satellite navigation system in low Earth orbit would need about 10 times more satellites than a similar satellite constellation in medium Earth orbit, Kassas explained. But as the recent rise of Xona and other competitors shows, lower manufacturing and launch costs have made it possible to build and launch such a satellite constellation dedicated to delivering PNT services from low Earth orbit.
Building and launching the satellite fleet
Xona has contracted with Aerospacelab, a satellite manufacturer in Belgium, to build some of the first satellites that will carry Xona’s PNT payloads into orbit. But the company is focused on developing its own in-house satellite bus to manufacture most of the planned 258 Pulsar satellites at the company’s factory in Burlingame, California.
“Our first hire on this internal satellite team was a little over a year ago, and seeing what the team has accomplished to date is incredibly impressive,” Perkins said. “Being able to bring in folks that have that experience can help us drive from what the first version looks like to how we continue to streamline that.”
One of Xona’s latest notable hires, Tim Graham, worked on engineering challenges at SpaceX for a decade, eventually becoming the engineering manager for avionics on the Raptor engines that propel SpaceX’s Starship rocket. But he saw an opportunity to lend his expertise and experience in scaling up hardware production to Xona and joined the company earlier this year to lead satellite development across hardware, software, and propulsion.
“If you look at the historical impact of major technological developments, GPS is up there as world-changing,” Graham told Ars. “Bringing a more modern design for a modern technology GPS system to the world is a pretty exciting mission.”
Graham also appreciated joining a company headed by Xona co-founder and CEO Brian Manning, who previously worked as a SpaceX engineer on redesigning components of the Falcon 9 rocket’s thrust structure. “SpaceX people have kind of been through the grinder together, and so it was a good match,” Graham said.
The company has already produced the two in-house satellite buses that are scheduled to join the launch in October 2026. When Ars spoke with Xona’s team in June, the satellite buses were undergoing vibration testing to see how well they could endure the simulated stress of rocket launches. Pushing the limits of hardware early and often can provide insight into failures that are much easier to understand and mitigate well before the satellite launches into orbit, Graham said.
“I cut my jib with the SpaceX mentality of tests… a test that doesn’t break something or show you something new is not super valuable,” Graham explained. “Let’s just try it and see what works, see what breaks, and then make it stronger.”
Xona is also designing and building the Pulsar satellites to be compatible with practically any rocket launch provider. “There’s a whole range of new launch providers that are just starting to come online and are coming in at some pretty competitive cost points,” Graham said. “So we’re really trying as part of our overall satellite design to be compatible with that future of the launch ecosystem, so that we can leverage both launch opportunities and lower launch costs as things come up within that sector.”
The goal is to enable maximum flexibility and minimize the time needed to launch the Pulsar constellation, while planning ahead of time for how many Pulsar satellites may fit each launch option. “We want to work with absolutely everyone,” Perkins told Ars. Such planning necessarily requires design trade-offs on each satellite’s mass and form factor, but “the engineers love nerding out on this bit,” he said.
Hardware compatibility and accessibility
Xona is not alone in working toward establishing PNT services based on low Earth orbit satellites. For example, the Virginia-based startup TrustPoint aims to deliver early service positioning, navigation and timing (PNT) services from low Earth orbit starting in 2027 and eventually build out a constellation of 300 satellites. TrustPoint has focused on using C-band satellite signals in the 4 to 8 gigahertz range instead of L-band signals in the 1 to 2 gigahertz range to allow for greater data transmission and to complicate jamming or spoofing efforts, according to SpaceNews.
However, Xona took a different route by instead making Pulsar satellite signals compatible with ground receivers designed for L1 or L5 band signals. That decision helps to make Pulsar satellite signals work more readily with ground receivers and chipsets that are currently designed for L-band signals from GPS and other global navigation satellite systems. The company claims some existing hardware and receivers would only require a firmware and software update.
“Our engineers review the manufacturer’s product and its intended application, develop a tailored test plan together, and validate that the implementation receives the signal,” Perkins told Ars. “The beauty is that it doesn’t actually require the hardware to be redesigned.”
Toward that end, Xona announced its Pulsar Verified program on July 9, 2026, that provides the custom test plan for each hardware manufacturer to ensure compatibility with Pulsar signals. Companies that have already signed up for the program include leading PNT companies such as Trimble and Septentrio, along with STMicroelectronics, Safran, StarNav and Keysight.
“What makes Xona stand out from other contenders is that they’re aiming to create receiver ecosystem adoption,” said Kassas at Ohio State.
The rise of more satellite constellations in low Earth orbit has even created new opportunities for independent navigation solutions. Kassas and his colleagues have used off-the-shelf antennas and created software algorithms to harness the signals from satellites operated by Xona and many other satellite providers that do not even operate dedicated PNT services, including Starlink. Their navigation solution’s eavesdropping technique measures the signals’ Doppler shifts—a throwback to the Transit satellite system’s pioneering demonstration of satellite-based navigation capabilities.
