The rise of LEO PNT

Listen to this content

0:00 0:00

Today’s commercial innovation requires infrastructure that moves at the same pace.

Essence

The rise of commercial satnav

Everyday life is saturated with location-dependent devices. They are multiplying faster than ever and their requirements have surpassed what GPS can support. Innovation in low-Earth orbit (LEO) satellites have seen exponential growth in the last ten years, unlocking new possibilities in further connecting our world.

In 2016, the total number of satellites operational in space from commercial and government operators was approximately 1,500. This number had been stable for decades, with linear growth since the launch of Sputnik in 1957. Today, there are now more than 8,000 satellites operational in space — with nearly all growth happening in LEO.

There are multiple reasons why. The cost of space access has decreased with reusable rockets and greater competition. The demand for connectivity has driven deployment of multiple constellations to deliver Internet from space. Latency is extremely important in communications and resolution in Earth observation.

While innovation in LEO satellites has primarily focused on connectivity and Earth observation, there is a generational opportunity to innovate in the position, navigation and timing (PNT) infrastructure that silently powers modern life.

There are now more than ten entities working toward deployment of dedicated PNT functions in LEO, amounting to more than 2,500 satellites if every constellation was complete today. As shown in Figure 1, five of these entities have already collectively launched more than 50 satellites. This market signal is not surprising, as demand for greater precision, power and protection are becoming fulfilled with diversification in LEO.

Figure 1. Launches of LEO PNT satellites.

Essentials

Medium-Earth orbit (MEO) has been the traditional choice of satellite navigation for global systems, with GPS, Galileo, BeiDou and GLONASS all being deployed in this regime. This altitude in the outer Van Allen belts is the harshest radiation environment Earth orbit satellites are subjected to and is a major driver in the cost and complexity of the satellites. From a commercial standpoint, deployment in LEO is more attractive as the more benign radiation environment allows for the use of more commercial off-the-shelf (COTS) parts in satellite designs, facilitating volume production. With a healthy ecosystem and supply chain now developed around LEO for both satellites and launch vehicles, the opportunity for commercial PNT to set a new standard in performance and protection is open.

The time for innovation in PNT could not be more urgent. Innovators are pushing the frontiers of technology across every industry and market. Physical intelligence is proliferating in the form of self-driving cars, humanoid robotics, automated farming, unmanned aerial systems and more. As these systems begin to coexist in the real world, the tools they rely on have never been more at risk. Commercial aviation is regularly jammed in Europe and the Middle East due to ongoing conflicts. And ships at sea are struggling to adapt to an environment where spoofing is commonplace.

The commercial world has different and increasingly more stringent requirements than government-focused systems like GPS. GPS was designed primarily around military requirements and is longstanding infrastructure that is difficult to change with the myriad number of deployed devices that depend on it. This responsibility makes GPS too big to fail, but also incredibly difficult to change.

GNSS infrastructure has unlocked so much in commercial activity. There are now more devices using GNSS than the Internet, and GPS is by far the majority user of the technology (based on nearly 7 billion active GNSS devices on Earth and around 6 billion users of the Internet.) However, commercial users have limited input to the evolution of GNSS constellations, which has led to a widening gap between technology and wants, which provides for the current commercial opportunity.

Simply put, today’s commercial innovation requires commercial infrastructure that moves at the same pace to support.

Elements

Architecting LEO PNT

For a LEO satellite navigation system, many designs could be considered, as reflected in Table 1 from Reid et al. (2025) outlining current public information about systems already announced. These constellations range from government-supported systems, which could act as extensions of already deployed global or regional systems, to commercial systems that target potentially unique, independent markets.

Table 1. Comparison of dedicated LEO PNT systems, deployments, and plans. Note that satellites already deployed were verified on celestrack.org .

These constellations all have one thing in common: they aim for between 200 and 300 LEO satellites. The reason is simple: as LEO satellites have a footprint of approximately 1/10^th that of medium Earth orbit (MEO) satellites, and between 20 and 30 MEOs are required for global PNT, approximately 10x more LEOs are needed to obtain similar coverage. A consequence is that in LEO, the radio energy is spread over 1/10^th the area compared to MEO, which has implications for power needs at the satellite — 10x less in LEO for the same MEO power in the same band.

There is another crucial parameter to consider in LEO PNT design: spectrum. Table 1 shows that many approaches are being considered. Xona’s approach with its Pulsar constellation was centered around three major areas of commercial appeal: seamless operation with existing devices; increased native accuracy; and added resilience to jamming and spoofing. An important philosophy adopted early in the company’s culture was to not make development a science project — that is, do not reinvent the wheel, but rather upgrade the engine. GPS was a revolutionary technology, which is why it is so heavily adopted and brings so much value to the world. Therefore, stand on the shoulders of this giant to look out to the future.

Ease of integration was the first consideration, as it has been the most important aspect in accelerating adoption of any new system. And spectrum is key to Integration. By launching a new system that uses the existing L-band signals, the GNSS ecosystem producing approximately one billion new units per year can seamlessly upgrade their capability without new hardware. Xona’s first technology pathfinder satellite in 2022 validated this hypothesis. While the pathfinder mission supported two satellite frequencies already in the regional navigation satellite system (RNSS) bands — one near L-band E6 and the other in the yet unused C-band near 5 GHz — it became apparent that receiver companies were willing to develop hardware for the L-band signal, and did so quickly with their existing hardware. There was resistance and longer timelines to global adoption for C-band signals.

In response, Xona shifted the production signals to a dual L-band system, which already has nearly a dozen commercial receiver partners tracking the recently launched production satellite — some within weeks of the launch. The challenge is to choose a waveform that is near existing GNSS bands, familiar in form and function and digital signal processing techniques to what is already fielded today, and to not cause harmful interference to the existing GNSS services in orbit. The resulting design is shown in Figure 2, on the right. The key innovation was the selection of a bandwidth efficient form of quadrature phase shift keying (QPSK), which focuses the energy in the central lobe and rolls off quickly compared to a traditional binary phase shift keying (BPSK) signal, shown in Figure 2 on the left for comparison. The result is a 100x stronger signal that does not cause harmful interference to existing GNSS signals, while offering resilience through more signal power. This selection process was iterative, taking feedback from the receiver community. More information on the design and testing for compatibility can be found in Reid et al. (2025).

Figure 2. (Left) GPS BPSK-based signal waveform, and (right) Pulsar QPSK-based signal waveform.

In addition to compatibility and ease of integration, accuracy and resilience are critical design drivers. For example, farmers rely on their equipment positional accuracy to efficiently distribute seeds, fertilizer and water, reducing waste and improving crop yields. Positional accuracy also enables accurate, repeatable field operations year after year, saving time, fuel and money while protecting the soil. Because GNSS typically offers meter-level positioning, today many farmers buy positional accuracy through GNSS correction services to obtain centimeter-level positioning. The Xona architecture leverages these techniques in precise point positioning (PPP), delivering precise ephemerides direct from the space segment, and combining them with the fast motion from LEO satellites (compared to MEOs) to reduce position solution convergence times from ~10 minutes to nearly instantaneous (see, for example, Mah and O’Keefe, 2025). This geometry also boosts coverage, as correction services today typically rely on geostationary satellites and do not service high latitudes, where they would benefit missions such as mining operations for critical minerals and polar navigation.

Connectivity relies on resilient timing. Passing more data through a network means efficiently meshing data packets in synchronized manner. Telecommunications and data centers need such connectivity to function. Authentication is expected in our communications systems, which is largely unavailable in civil GNSS signals. In an age where GNSS spoofing is done to cheat at games like Pokémon Go and now more frequently for nefarious purposes, authentication becomes essential for a modern system (Anderson, 2025, and Xona, 2025a). For resilience to spoofing, Xona included not just data authentication, but also range authentication, so that users can ultimately authenticate their position.

Defense applications require resilience to jamming. World conflicts, particularly currently in Ukraine and the Middle East, have showcased GNSS vulnerabilities in the presence of widespread GNSS jammers. However, this problem is no longer only a defense issue. In 2025, nearly 123,000 commercial flights in Europe were disrupted between January and April alone by GNSS jamming (GPS World, 2025). For resilience to jamming, one method is more power. LEO being 20x closer to Earth than MEO affords nearly a 10x boost in power for the same power transmitted at the satellite. Xona’s target was 100x more power to the end user to significantly reduce the effective range of a jammer by more than six times as shown by recent field trials. Such a transmission power translates to a >97% reduction in affected area and means threats shift to larger and less practical platforms for adversaries, i.e., from requiring handheld devices to backpacks or even truck-sized jammers.

More signal power also has implications for indoor positioning. Internet of things (IoT) devices such as asset trackers are commonly affected by signal obstruction and attenuation during transit, particularly in indoor environments, urban canyons, under foliage, or when obstructed by vehicles and cargo. Warehouses, shipping containers, and other constraints limit where position can be determined. Even coarse indoor positions can support operational intelligence for asset management.

Launching LEO PNT

Pulsar is designed to launch in stages as shown in Figure 3, which unlocks capability in tranches that expands the number of features and ultimately the user base. While Pulsar will achieve persistent coverage across major markets at the deployment of 16 operational satellites, earliest customers in time transfer will see value from Pulsar much sooner as an independent source of timing synchronization for devices with holdover clocks. At 16 satellites, Pulsar will achieve persistent 1-satellite-in-view service, unlocking precise time transfer and coarse positioning for stationary users, including indoors. Pulsar also provides a link to stream GNSS corrections, building on a partnership with Trimble. Full resilient positioning will come online with GPS-level satellite visibility. First in the midlatitudes, with 192 satellites, and then globally with the deployment of an additional 66 satellites into polar orbit, bringing the total to 258 operational satellites.

Figure 3. Pulsar constellation satellite launch stages.

Xona launched its in-orbit-validation stage in June 2025 with Pulsar-0, the first production-class satellite representative of the scaled capability in terms of signal modulation, power and features. Pulsar-0 allowed for performance validation of the complete system, not just of the payload in space but also the tangible benefit to users on the ground. For scale, Figure 4 shows the 150 kg class satellite pre-launch, including its integration on the Falcon 9 launch vehicle. Launch cost has been become more accessible, unlocking the ability to launch larger spacecraft by commercial entities, which can have larger positive impact on the ground (Xona, 2025b).

Figure 4. Xona’s first production satellite Pulsar-0.

LEO PNT on-orbit

In almost 6 months since launch, Pulsar-0 has been tracked in more than 6 countries, 12 third-party receiver protypes, and has achieved several performance milestones that signal the groundbreaking capability Pulsar will deliver to users everywhere when the full constellation is operational. Early performance tests are built to showcase the value and features most important to commercial users in realistic settings.

Accuracy. Figure 5 illustrates a signal-in-space user-range-error (SISRE) of 43 mm — about the diameter of a golf ball. This performance represents a more than tenfold increase in accuracy compared to that reported by GPS (Refro et al., 2024). The implication is an ability to natively perform PPP at the centimeter level, without an additional data link or correction layer.

Figure 5. Estimate of SISRE for Pulsar-0 ranging signal compared with nominal GPS.

Security. Xona is the first organization to show pseudorange authentication from orbit, accomplished using the Pulsar-0 satellite within weeks of the launch (Anderson, 2025). Pulsar is built from the ground up to be secure by design, combining cryptographic authentication of both navigation data and satellite ranging signals with rapidly authenticated signal verification — aiming for a time-to-authentication of approximately four seconds. This layered security significantly raises the technical and financial bar for would-be spoofers. A spoofer spoofing a single satellite continuously should succeed in fooling one second of a Pulsar receiver’s ranging once every 130 years (Xona, 2025a).

Jamming. Pulsar-0 signal testing has been conducted under live-sky jamming conditions at several jamming events, including Jammertest 2025 in Norway. These campaigns confirmed that using the Pulsar X5 signal can reduce the effective radius of a jammer by 6.3 times as compared to GPS L5 — in other words, less than 3% of the affected area compared to GPS. The same targeted power, bandwidth and type of jammer waveform was used against GPS and Pulsar, including center frequency. For context, Figure 6 shows the implications for a 1 Watt jammer scenario in San Francisco and the reduction brought by a 6.3x reduction in radius.

Figure 6. ffective jamming areas for Pulsar X5 and GPS L5 from a 1 W jammer in San Francisco based on Jammerfest 2025 test results.

Indoor. Data were collected for several navigation passes per day at multiple locations, including indoors. These include passes at Xona headquarters in Burlingame, California, and its office in Montreal, Canada. The most challenging indoor environment was Montreal, on the third floor of an industrial and primarily concrete building with two floors above. Figure 7 shows the Pulsar-0 power profile during a typical pass, peaking at the highest point in the sky. This structure is an artifact of the antenna gain pattern used in this mission. Designed for a higher altitude for deployment of later satellites, the pattern will be more isotropic with future satellites launched near 1100 km altitude compared to Pulsar-0, which is closer to 500 km. Near apex, the signal penetrates indoors, and this short segment proves to be sufficient for indoor positioning for stationary users. Leveraging techniques based on Doppler and including pseudorange, early results indicate sub-10 meters both outdoors and indoors.

Figure 7. Comparison of Pulsar and GPS signal strengths on roof and indoors at Xona Montreal office. — Figure 7. Comparison of Pulsar and GPS signal strengths on roof and indoors at the Xona Montreal office.

EVOLUTIONARY

The coming years will be about gaining operational experience and in scaling the constellation with a near-term focus on the first batch of 16 satellites. Pulsar-0 has already confirmed its value proposition: attaining major milestones in performance including accuracy, security and jamming, but perhaps most importantly in the integration of user equipment. The next year is about working with customers in specific industries and use cases as Xona moves towards deployment of early operational service.

The future of LEO PNT is bright. Theory has evolved to prediction, which is now evolving to reality. The early results appear to lead to an exciting PNT future with LEO PNT expanding the GNSS revolution in terms of security, interference mitigation and system availability both outdoors and indoors for a myriad of current and new applications and users.