The Mission Behind the Mission

As with all great ideas, it started with a block diagram built from bar coasters over a few beers. The math we had supported the state estimation and signal design needed for a next generation positioning constellation. The idea was simple in principle, and all the necessary blocks existed as off-the-shelf components: we had found a clear path towards providing Low Earth Orbit PNT services that would outperform the de-factor gold standard for satellite positioning technology, and at a fraction of the price. The challenge, then, was to prove it. To actually assemble the pieces, write the software, and launch the resulting system into orbit.

GPS Wasn’t Built for the Demands of the Modern World

The United States launched the first Navstar satellite in 1978, paving the way for time and location to become constants in the modern world. Referred to as “electronic lighthouses in the sky” by newscasters at the time, these orbiting platforms have shaped the way humanity moves, communicates, and lives. By the time the final satellite of that first generation was retired in 1995, modern life had already grown dependent on the broadcasts it provided.

Today, GPS underpins nearly every facet of daily life. It enables the movement of material goods and people, it powers our financial markets, it synchronizes our energy grid, it guides aircrafts and ships. It supports precision agriculture and emergency services for billions of people. But while the pace of innovation has accelerated dramatically, the infrastructure that powers this global system remains largely unchanged since its original deployment.

At Xona Space Systems, we’re building a new kind of location and timing infrastructure—one that’s accurate enough, resilient enough, and scalable enough to meet the demands of today’s technology. Pulsar is our vision brought to life: a system that uses small, efficient satellites in Low Earth Orbit to deliver precise, reliable positioning and timing services anywhere on the planet.

When we started Xona in 2019, this premise was unproven. Nation-states had long been the only ones to operate global navigational constellations, and none had done it in Low Earth Orbit. It was unclear if it could even work, let alone work at scale. But we believed that if we could prove it, it would open the door to an entirely new playing field of innovation.

So we set out to try.

When launched in 2022, Huginn became the first commercial satellite navigation mission in orbit.

First Steps

The first major hurdle we encountered in our mission was to prove that this novel architecture would indeed outperform what had become the status quo for global positioning systems. Doing so would effectively establish that LEO-based PNT was not only a viable technology, but the best solution for the technology’s future. To prove our architecture was more than just an idea, we had to leverage a range of recent advancements and design paradigms in the PNT industry.

To start, access to space had gotten a lot cheaper, and the world was seeing a proliferation of satellite manufacturers and launch vendors bringing down what was once an inaccessible cost. The explosion of software-defined radios meant, as well, that anyone could build their very own radio broadcasting any signal they wanted to. With an LEO constellation in between GPS and Earth, we were able to leverage connectivity between our own satellites, terrestrial-based atomic clocks, and atomic clocks based on GNSS platforms to solve for long term stability with a broad network of timing nodes, allowing us to replace the expensive atomic clock in each LEO PNT satellite with a much lower-cost unit. Through these initial strategies, we had identified a solution to one of PNT’s first competitive gates: cost. 

Innovating Against Challenges

As we dug into the build, solving the cost problem was just one of many challenges. We learned key nuances with each of the recent advancements we had leveraged. While the cost of access to space was indeed dropping and the Small Sat industry was growing, the LEO industry was designed primarily around imaging constellations which required significantly lower power than what was needed for our PNT payload. Breaking this power barrier required moving from an independent satellite concept to a hosted payload for our 2022 launch, where Xona’s demonstrator payload, named Huginn, would become one of several all sharing the host platform’s power capability. While not a viable long-term option, it allowed us to move and deploy quickly to demonstrate the core technology’s potential and to prove the plan worked, and that it worked well.

Another identified obstacle–the one most critical to our success–was achieving broad compatibility with the receivers and chipsets that turn Pulsar's signals into actionable data for devices. Huginn was designed around two signals: one in L-band, the widely accepted standard that GPS leverages today, and one in C-band, an emerging frequency in a spectrum region that is much less crowded. For a navigation system, two signals with frequency diversity allow a receiver to remove atmospheric interference on the signals. To transmit in both frequencies, we settled on a design that digitally generated the baseband (the ranging code and all the data bits) that were mixed and upconverted to the correct frequencies in the analog domain. While both systems were tied to the same clock signal and were, theoretically, synchronized, there were still some small variations that presented themselves resulting in an apparent drift between the components to the end user. Ultimately, we were able to overcome these challenges without falling back to an atomic clock by way of a sophisticated algorithm and unique hardware combination in our payload upgrades destined for our next mission.

Challenge after challenge, we continued our journey and launched our Huginn mission in 2022 as the first commercially funded navigation mission in space, proving Pulsar’s potential in delivering PNT from Low Earth Orbit.

Even with the model proven from Huginn, it was one thing to demonstrate that it was possible to generate a signal that could outperform GPS; it was a very different effort to operate a constellation of satellites that could provide better services than GPS was ever capable of.

GNSS systems classically break themselves down into three segments: a space segment, a ground segment, and a user segment. With our first mission, Huginn demonstrated key elements of the space segment. Back on land, our business team was fast at work building up the interest and drive from our user segment. The ground segment, however, was what really needed the attention. There was plenty left to do.

Proving the model of PNT from Low Earth Orbit, Huginn become the model for building our developing our commercial service.

Redesigning from First Principles

After our Huginn pilot, we hunkered down on integrating key learnings as we progressed towards launching and scaling up our commercial service. A single satellite broadcasting a signal was a milestone achievement for the industry, but not the solution to solve problems for real users. Customers don’t just need proof: they need a signal that’s always on, from a system that’s always working. That means constant availability, real-time performance, and a system designed from the ground up to scale.

To get there, we asked ourselves: what does a production-grade LEO PNT service actually require to be trusted by industries around the world?

That question became our guide to architect the system that will power our Pulsar service. It led to a more rigorous set of first principles built around universal compatibility, uncompromising performance, and designing for scale. These weren’t aspirations, they were engineering requirements. They shaped every part of what came next.

Universal Compatibility: Building a Service People Can Actually Use

To build broad acceptance in Pulsar across industries, continents, and communities, our service cannot depend on specialized hardware; the next generation of location and time technology must be compatible with the billions of active devices in use today. We learned with Huginn that the C-band signals proved much more challenging for manufacturers to integrate into existing user equipment than we anticipated. The C-band signals were also shown to offer fewer benefits to jamming resistance than initially expected. Thus, we tabled C-band for the time-being and increased our investment into L-band, identifying more portions of the spectrum to develop our X1 and X5 signals. These proprietary production signals were designed from the start with compatibility in mind, meaning they already had a vast ecosystem of receivers and chipsets that could work with just a firmware update. When our new service becomes active, it would mean market compatibility with devices that were already in use.

Another advancement that we leaned into was the accessibility of FPGAs (Field Programmable Gate Arrays) capable of direct digital synthesis of the entirety of the signal, including the carrier itself. With direct digital synthesis, we could create navigation signals entirely with math, predictable and precise, unlike analog circuits whose performance changes with temperature, time, and other variables. Moving to a completely digitally generated signal also enabled us to better control the variations we had seen with Huginn, resulting in a signal that provides users the consistent precision they need from their PNT system. 

Uncompromising Performance: Setting a New Gold Standard

The potential Huginn demonstrated for Pulsar showed there was room to vastly improve on the status quo of modern PNT signal performance by way of additional system power. Due to the shared nature of the mission, our payload operated well below the maximum regulatory power levels allowed. This meant we had power to spare for future missions, and that we could leverage every bit of that power to deliver a stronger signal to the end user. More power dedicated to the user allowed us to significantly expand the availability of the signal (through trees, buildings, etc.), drive better performance in our receivers (acquire and track the Pulsar signals themselves), and develop better resistance to outside threats such as jamming and spoofing. To that end, our payload got a facelift – keeping the same architecture, the same algorithms, and the same philosophy, we upgraded the payload to support a substantial increase in the signal power.

To support this additional power and broadcast Pulsar’s X1 and X5 frequencies, our antenna also got a major upgrade. It was a first of its kind: no one at the time was transmitting a Radio Navigation Satellite Signal (RNSS) at these power levels from an LEO satellite, especially in an isoflux antenna pattern – a pattern that resulted in constant power to the end user as the satellite passes overhead. Navigation signals, used in this capacity, are intended to be broadcast over the entire field of view of a satellite at all times, ensuring that the user on the ground can truly see the signal from essentially horizon to horizon. Since there was no simple off-the-shelf antenna designed for our mission, we had to build one tailor-fit for our end user, resulting in the best possible PNT performance for the modern era.

Built for Scale: Preparing to Launch More, Faster

Moving beyond a simple tech demonstrator to a satellite that needs to provide customer-facing service meant moving away from a hosted platform to a dedicated satellite of our own. Our payload needs a lot of power, and it needs it around the clock. Alongside the power requirements, our own payload didn’t play well with the others: we needed to maintain a nadir-facing orientation, vying for attitude control that didn’t align with imaging satellites on the shared payload. While the industry was expanding the availability of satellites at a fast rate – fast even for “satellite years” – it still wasn’t fast enough for our vision. We needed to adopt an incremental approach in expanding towards the global coverage we aimed for while still launching quickly and efficiently. To that end, we recognized that the satellite bus-based challenges were going to be a limiting factor for us. Our design efforts thus went towards ensuring a bus-agnostic design, allowing us to leverage as many satellite bus manufacturers as necessary to get us up and rolling quickly.

Weighing against Huginn’s initial demonstration, and pivoting towards a larger vision, we made an additional key improvement to our payload: we incorporated redundancies throughout our system architecture. Our payload’s hardware is now designed with modularity for future generations in mind, enabling easy hardware updates that are both isolated to a specific subsystem or even larger, more systematic hardware changes. In terms of specific redundancies, we moved from Huginn’s single string design to a design that leverages redundancy through hot and cold spares for all critical systems. Where possible, we introduced “R&D paths” that, as opposed to providing an identical cold spare, provided an R&D path that we could activate to test experimental hardware or functionality in support of the next-generation build.

These improvements reflect what it truly takes to earn global trust in a production-grade LEO PNT service: reliability, flexibility, and the ability to evolve without disruption. But the world doesn’t just need satellites—Xona needs to provide comprehensive positioning infrastructure around the globe.

Our Huginn mission delivered real-world insights at a small scale, helping us accelerate the development of our full constellation and service.

Building the Platforms for Commercial Operations

A satellite without an operational backbone is really just floating metal making noise in space. To deliver a true commercial service, it’s not enough to launch something that works – it has to work everywhere, all the time, with the unseen infrastructure to support it behind the scenes. That’s why, alongside redesigning our space segment, we’ve invested deeply into the systems and tools required to operate Pulsar as a real-time, customer-facing platform.

In 2022, our Huginn mission didn’t involve just “a” human in the loop to operate – it involved a whole team of humans working tirelessly to keep the loop intact. Commanding, scheduling, and uploading were performed and coordinated manually, even down to relying on Zoom calls to connect folks directly with operators across the West Coast.

Today, operational control of the payload shifts entirely to Xona, where dedicated mission operators are responsible for payload tasking, mission planning, and backhaul scheduling directly. The satellite vendor is now only responsible for the health and safety of the core satellite system – giving Xona full control over its service delivery.

Ground Infrastructure Designed for Speed and Scale

One core aspect of our algorithms and our offering to our end users is near real-time information from global monitoring stations – an operation we performed only in post-processing for Huginn. This means we are able to close a real-time loop between what we see on the ground and our satellites, affecting everything from real-time performance feedback to near immediate response to any anomalies observed anywhere around the world. Our autonomous-forward approach is driving the development of a robust cloud infrastructure to operate, monitor, and control our payloads in real-time with minimal human intervention. This decentralized approach to our operations further increases our resilience to outages or failures, unlocking the ability to task and control our constellation from around the globe.

We applied lessons from our Huginn mission to develop our first production-class satellite, designed from the ground up to meet our mission needs with improved technology and systems architecture.

Looking Ahead

The way the world uses time and location is changing. The remarkable systems that have supported global navigation for the past forty years were built for a different era. Today’s technologies need something new – infrastructure that is more accurate, more resilient, and more responsive to change.

With Pulsar-0 launching this June, we are taking the next step towards that future. This mission is the result of years of iteration and reflection, shaped by the lessons from Huginn and grounded in a new set of principles: compatibility with today’s devices, performance that meets the demands of tomorrow’s applications, and an architecture designed to scale.

We redesigned our signal from the ground up, moved to a fully digital system, and increased the power and precision of our payload. We built tailored hardware unique to our mission profile and introduced redundancy across critical systems. We shifted from a shared satellite bus to a purpose-built platform that supports sustained operations. And we brought mission control in-house, supported by a global, cloud-based infrastructure built for real-time responsiveness.

Over the next two years, we will continue expanding the constellation, refining the service, and working closely with partners and customers to bring this system into real-world applications across industries.

This is how we rebuild the foundations of progress. By turning a novel concept into working infrastructure and turning working infrastructure into the future of global innovation.