Building the GPS Replacement Nobody Asked For (But Everyone Will Need)

GPS was designed in the early 1970s. The orbital geometry was optimized for Cold War-era military needs. The signal power budget assumed receivers with antennas pointed at the sky in open terrain. The authentication model — there essentially wasn’t one. For decades, none of this mattered much. GPS worked well enough, and “well enough” is a powerful force in infrastructure.

It is no longer well enough.

The applications now demanding precision positioning — autonomous vehicles operating at highway speeds, swarms of agricultural robots, drone delivery networks, autonomous maritime vessels, time-synchronization for financial infrastructure — weren’t in the design envelope when the first GPS Block I satellite launched in 1978. Neither was the threat environment: GPS jamming and spoofing have become routine tools of both state and non-state actors, and the signals that underpin an enormous fraction of global economic activity are, by design, unauthenticated and easy to replicate.

Xona Space Systems is building the system that GPS would be if you designed it today.

What Pulsar Actually Is

Pulsar is a planned constellation of approximately 300 satellites in low Earth orbit, delivering positioning, navigation, and timing signals that are, by most meaningful measures, a categorical improvement over GPS. The signals are roughly 100 times stronger — a direct consequence of operating from LEO at approximately 600 km versus the GPS medium Earth orbit at around 20,200 km. That power advantage translates to better performance in urban canyons, under foliage, and in any environment where signal attenuation currently degrades GPS reliability.

The accuracy target is centimeter-level. Current GPS under ideal conditions delivers roughly meter-level civilian accuracy. Centimeter accuracy requires different signal design, different receiver architecture, and a fundamentally different approach to atmospheric error correction — all of which Xona is developing in parallel.

The authentication is cryptographic and native to the signal, not a retrofit. This is the distinction that matters most for defense and critical infrastructure applications. GPS spoofing works because the signal carries no proof of origin. Pulsar signals are designed from the ground up so that a receiver can verify it is receiving a genuine signal from an authenticated satellite — not a ground-based transmitter running an impersonation attack. This is not a feature added on top of an existing signal design. It is a property of the signal architecture itself.

The constellation geometry — 300 satellites in LEO — means faster satellite revisit rates, better coverage geometry, and lower latency than medium-orbit constellations. It also means a significantly more complex ground and space system to operate.

June 2025: Pulsar-0 and What It Actually Proved

In June 2025, Xona launched Pulsar-0, their first production satellite. The achievement most worth noting is specific: Pulsar-0 successfully demonstrated authenticated navigation signals from LEO. That had never been done before. Prior LEO PNT research had produced signals. Prior satellite programs had produced authentication. No one had combined them in a working production satellite and closed the loop with receivers on the ground.

For a company building infrastructure that other systems will depend on, Pulsar-0 served a purpose beyond engineering validation. It demonstrated to potential customers — autonomous vehicle developers, defense contractors, precision agriculture platforms — that the signal standard is real, the hardware works, and the timeline is credible. In infrastructure markets, credibility is a product.

The $170M Series C and What It Funds

In early 2026, Xona raised $170 million in a Series C round. The capital is going to three places: scaling satellite production and constellation deployment, building out the ground infrastructure needed to operate a 300-satellite network, and developing the user equipment ecosystem — the receivers, chipsets, and integration reference designs that make Pulsar signals accessible to end users.

That third category is where many satellite ventures underestimate the work. A signal in orbit is not a product until someone can receive it. GPS succeeded in part because the receiver ecosystem eventually became cheap enough for consumer devices. Xona needs to compress that development timeline dramatically, which means investing in receiver silicon simultaneously with the constellation build.

The funding also supports continued FCC licensing and international spectrum coordination — a regulatory engineering effort that runs in parallel with the technical one and carries its own deadlines and dependencies.

The Systems Engineering Problem That Has No Precedent

Building a new satellite constellation is hard. Building a new navigation signal standard is hard. Doing both simultaneously, while also building the ground infrastructure and the user equipment that make the whole system usable, while coordinating international spectrum rights, while managing a regulatory process that involves multiple governments — that is the problem Xona is actually solving.

The specific difficulty is this: there is no existing Pulsar to reference. GPS was extended and modified from a known baseline. Galileo and BeiDou were designed with GPS as a prior art reference point. Pulsar is not an incremental improvement on a prior system. It is a clean-sheet design of a new signal standard. When you are designing a new signal standard, your signal design requirements flow down into spacecraft hardware requirements, which flow into ground system processing requirements, which flow into receiver design requirements — and all four of those domains must stay synchronized, because a change in one propagates into the others in ways that are not always obvious until something fails to interoperate.

Consider one example: the cryptographic authentication architecture. The choice of cryptographic scheme affects signal bandwidth, which affects receiver processing load, which affects chipset power consumption, which affects the receiver form factor for battery-powered agricultural robots versus rack-mounted defense systems. These are not independent design decisions. They are a tightly coupled requirement chain that spans four engineering domains, and a change in any link requires a managed, traceable response in the others.

This is textbook systems engineering — and it is extraordinarily difficult to execute in practice when the system is entirely novel and the design is still evolving.

Managing Requirements Across Four Domains at Once

Xona uses Flow Engineering as their requirements management platform. The choice reflects the shape of the problem: four distinct subsystem domains — signal design, spacecraft systems, ground infrastructure, and user equipment — each with their own engineering teams, each generating and consuming requirements that connect to the others.

In a document-based requirements management approach, the coordination between those domains happens through review cycles and version-controlled documents. When a requirement changes in the signal design domain, someone has to identify the affected documents in the spacecraft domain, update them, route them for review, and verify that the changes propagated correctly. At the scale and pace Xona is working, that process becomes a bottleneck.

A graph-based platform — where requirements, their rationale, and their downstream dependencies exist as connected nodes rather than text in documents — makes the propagation of changes traceable and auditable. When the signal authentication scheme evolves, the dependency graph shows which spacecraft requirements depend on it, which ground processing requirements depend on those, and which user equipment test cases need to be revisited. The traceability is structural, not manual.

For a company working toward FCC licensing and international spectrum coordination, that traceability also serves a compliance function. Regulators want to understand how design decisions connect to performance claims. A requirements graph that links signal power specifications to spacecraft antenna design to orbit altitude to coverage geometry to interference analysis is a more defensible artifact than a set of documents that were separately maintained by separate teams.

What It Takes to Build Replacement Infrastructure from Scratch

Xona is not building a product that competes with GPS. They are building infrastructure that — if the constellation reaches full deployment — will operate alongside GPS, eventually reducing dependence on it for applications that need authentication, higher signal strength, or centimeter accuracy. The long-term trajectory is clear enough: GPS was not designed for the world that exists now, and it was certainly not designed for the world that autonomous systems are creating.

Building that infrastructure from scratch imposes a specific kind of engineering discipline. When you are extending an existing system, the existing system constrains your design choices in ways that simplify certain problems — you know what the signal format looks like, you know what the receiver has to do, you know what the ground system needs to handle. When the existing system is not your reference, every design choice is open, which means every design choice has to be made intentionally and documented in a way that makes the rationale recoverable when the choice has to be revisited.

That is not a description of a software company releasing quarterly updates. It is a description of engineering infrastructure meant to operate for decades, with receivers embedded in autonomous systems, medical equipment, financial networks, and defense platforms that have their own long service lives. Getting the signal standard right — getting the authentication architecture right, getting the spectrum coordination right — is not a problem you fix with a patch.

Honest Assessment

Xona has done something genuinely difficult: they launched a working satellite that demonstrated an authenticated navigation signal from LEO. That is a real technical milestone, not a promotional claim. The $170M Series C gives them the capital to execute the next phase of the constellation build.

The risks are structural. Building 300 satellites is a manufacturing and logistics challenge that has humbled larger organizations. The receiver ecosystem is a chicken-and-egg problem — receiver silicon needs a market, the market needs receivers — and Xona has to make investments on both sides before the flywheel spins. Spectrum coordination is slow, internationally complex, and not fully under Xona’s control. And the signal standard, however well-designed, has to achieve adoption in markets — automotive, defense, agriculture — where procurement cycles are long and switching costs are real.

None of that changes what Xona is building or why it matters. GPS is aging infrastructure with known vulnerabilities in a world that has built enormous dependencies on it. A stronger, authenticated, centimeter-accurate alternative in LEO is not a novelty product. It is a serious engineering response to a serious infrastructure problem.

The systems engineering required to deliver it — coordinating novel signal design across spacecraft, ground, and user equipment domains while managing a regulatory process across multiple governments — is the kind of problem that punishes improvisation and rewards discipline. The early evidence suggests Xona is approaching it with the latter.