The system is embedded across critical civilian infrastructure as well, with approximately 90 percent of U.S. 911 call centers relying on Safran timing technology. On the defense side, the SecureSync supports applications ranging from GPS-disciplined synchronization in standard infrastructure to M-Code enabled timing for military operations requiring the highest levels of security and integrity — including the Sentinel A4 radar program, where M-Code SecureSync units were integrated to strengthen resilient PNT performance against jamming and spoofing threats. 

“Timing has been foundational to who we are since day one, and this milestone is a testament to the trust our customers have placed in SecureSync for nearly two decades,” said Trevor Dougherty, Vice President of Sales and Marketing at Safran Federal Systems. “In an environment where a fraction of a second can mean the difference between success and failure, we don’t just deliver precise time — we make it resilient.”

The announcement comes alongside continued development of next-generation timing capabilities. In April, Infleqtion announced availability of the first quantum-enabled precision timing solution developed in partnership with Safran Electronics and Defense, integrating Infleqtion’s Tiqker quantum optical clock with Safran’s White Rabbit and SecureSync systems. White Rabbit technology enables picosecond-level time distribution — approximately a thousand times more precise than nanosecond-class timing — positioning the SecureSync platform for the next tier of defense and infrastructure timing requirements as GPS-dependent architectures come under increasing pressure. 

The post Safran Federal Systems Delivers 50,000th SecureSync Timing System appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

At the PNT Leadership Summit last September, Locata CEO Nunzio Gambale put a blunt question on the screen again and again: “What’s your replacement?”

He asked it over ports, offshore energy projects, precision agriculture systems and critical infrastructure sites operating in what his presentation called “red zones”—places where GNSS-dependent systems may fail, degrade or become unreliable because of jamming, spoofing or other forms of interference. Across those examples, the warning was the same: high-value civilian systems have been built around precision positioning, navigation and timing, but many still have no credible replacement when the signals they depend on are denied.

That argument has become progressively more difficult to dismiss.

Only months earlier, Gambale said, Ukraine’s June 1, 2025, Operation Spider Web demonstrated how low-cost, precisely coordinated stealth drone attacks could reach strategic targets far beyond the front lines. Ukraine said it used 117 drones, and the Council on Foreign Relations described the attack as evidence that low-cost precision strikes are becoming accessible to many state and non-state actors.

For Gambale, Operation Spider Web has forever changed the strategic logic of PNT. If the now ubiquitous drones can use satellite navigation to reach strategic assets, governments and operators defending those assets will have to increasingly jam, spoof or otherwise deny the signals those drones rely on. The result is a new kind of collateral damage: Civilian systems that depend on the same signals may be disrupted by the defensive measures intended to protect national infrastructure.

That was the September argument.

Since then, the jamming and spoofing environment has become more urgent, particularly around the Persian Gulf and the Strait of Hormuz. Meanwhile, in the Baltic area, Russian electronic warfare is already turning that risk into a live political and operational crisis. In May, Ukrainian officials said Russian electronic warfare had deliberately diverted Ukrainian drones into Latvian airspace, with repeated incursions culminating in explosions at an oil storage facility and contributing to the collapse of Latvia’s government. Inside GNSS+ reported that widespread GNSS interference in the Gulf and Strait of Hormuz region coincided with sharp disruption in commercial shipping, with maritime analytics providers documenting more than 1,100 vessels affected by GPS and AIS interference in a 24-hour period, including ships falsely positioned at airports, a nuclear power plant and on Iranian land.

That escalation makes Gambale’s question feel less like a conference provocation and more like an operational imperative.

The resulting challenge is more difficult than simply asking for a backup to GPS. For Gambale, that phrase is too vague to be useful. The real question is application-specific. 

“This isn’t simply about backing up GPS,” Gambale said. “The point of PNT is the outcome: What the application requires, and what can still deliver it when GPS is degraded, denied or no longer trusted.”

That is the core of his argument. The world did not adopt GNSS merely as a convenience; it built entire classes of infrastructure, automation and digital systems on top of it. Now the same signal dependency that enabled enormous economic value has also become a systemic vulnerability.

The Civilian Problem Has Changed 

For decades, GNSS interference was often framed as a military concern. Jamming and spoofing belonged to battlefields, contested borders and electronic warfare scenarios. Gambale believes that framing is “no longer even close to the reality.”

The drone era has changed the logic. If hostile drones use GNSS to navigate, then defending critical infrastructure absolutely demands the denial of that same signal locally. In other words, the jamming will not come only from the adversary; it will inevitably also come from the government or operator trying to protect its own critical assets.

“What’s the first thing you need to do for anti-drone systems?” Gambale said. “You need to jam the GPS, so that the enemy can’t use the same signal that you’re using. I can tell you categorically that in, say, the UAE, it’s not the U.S. or Israel or Iran that’s jamming Dubai or Abu Dhabi. It’s the UAE itself. We’ve heard credible reports that a GNSS jammer is now installed at the top of the Burj Khalifa. Think about that. It’s called ‘frequency fratricide’… and the Golden Dome, Drone Walls and many other national protection systems you see being built are now undeniable proof that ‘jam yourselves’ is the future.”

That creates what he sees as the new civilian crisis: The same denial zone meant to protect national strategic sites will inevitably disable the civilian systems built around satellite PNT.

“If you want to deny this magical capability to your enemy, you have to deny it to the areas around your critical infrastructure,” Gambale said. “However, you then jam the surveyors, you jam the harbor pilots bringing ships into port, you jam all of the autonomous systems, you jam the mobile phone technologies, you jam the timing for data centers, you jam the landing systems for aircraft. Uber Eats. Waymo. Google Maps.”

That argument is not merely a Locata argument. Gambale cites Doug Taggart, president of Overlook Systems Technologies and an ION Fellow, in the Spring 2026 ION Newsletter. Taggart argued that GPS now underpins transportation safety, economic activity, communication networks, precision agriculture and critical infrastructure, while the United States has spent more than 25 years struggling to identify a backup. Taggart’s conclusion was that resilient PNT capability should be understood as an inherently governmental responsibility, whether the physical systems are government-operated or commercially provided.

That framing shifts the debate from product or solution selection to public responsibility. The issue is not whether GPS remains essential. It does. The issue is whether critical systems can continue operating when GPS is unavailable, untrusted or locally denied.

The Port Test: What Happens When Precision Stops?

Gambale’s most concrete example, from Locata’s own experience in the jamming zones, is port automation. In his summit presentation, he used the Port of Gdańsk and major Baltic infrastructure projects to illustrate the new PNT reality. The point was not simply that ports use GNSS. It was that modern automation systems, such as in ports, logistics hubs, etc., all depend on very precise positioning—continuously and reliably.

The presentation described a $3 billion Port of Gdańsk expansion, with automation as a key part of Polish port infrastructure. It also described fully autonomous rubber-tired gantries—25 ordered, 26 meters high by 30 meters wide, $20 million each, using three RTK GNSS systems for autosteer and placement—with a requirement of less than 2 centimeters, 3 sigma, 24/7/365, without fail.

Large autonomous gantries and other automated systems do not need “some” positioning. They must have centimeter-level positioning, all day, every day. If the position solution degrades, the machine does not simply become less efficient. It stops dead.

“These machines are automated, and they’re stacking containers on top of one another autonomously, without any human in the loop,” Gambale said. “They must have two- to five-centimeter positioning, or else the entire system doesn’t work. This is not some academic argument. When an infrastructure site like Gdansk is jammed, the company literally owns $500 million dollars’ worth of ‘bricks.’ The company’s need for centimeter-level GNSS is dire. Jamming can cost millions per day. And that is a clear and existential threat to a business’ existence.”

He framed the problem in operational terms. A lower-accuracy backup may sound useful on a policy slide, but if it cannot support the application’s required precision, it does not solve the problem.

“If a ‘solution’ blows out past five centimeters, the machines must stop,” he said. “Something that gives you 2 meters of ‘GPS backup’ is of absolutely no use to that type of application.”

That distinction is central to his argument. The market does not need a generic conversation about backup. It needs a performance conversation: what accuracy, what timing, what integrity, what availability, what resilience under interference, and what happens when the system is spoofed?

If the answer does not meet the application requirements, then the infrastructure remains exposed, critically compromised and vulnerable.

Precision as Infrastructure

Gambale extends the same argument to offshore construction, surveying, logistics and warehousing sites, and precision agriculture. In each case, PNT is not a convenience layered onto the application. It is part of the operating system.

Gambale pointed out that view is strongly supported by ESA’s March 2024 NAVAC PNT Vision 2035 White Paper, produced under the guidance of NAVAC Chaiman, Luis Mayo. According to the report, more than 6.5 billion GNSS devices were already installed worldwide by 2021, with the installed base expected to grow to 10.6 billion by 2031. Also, according to the report, roughly 10% of EU GDP relies on GNSS to some degree, while consumer, IoT and automotive applications represent more than 90% of the market.

But the report’s most important point for Gambale’s thesis is not market size. It is dependency. NAVAC warns that as GNSS use spread across application domains, society built an increasingly deep dependence on these systems. The report identifies jamming, spoofing and interference as growing concerns, and specifically notes that accurate timing is the main critical use case for critical infrastructure.

That supports Gambale’s point: PNT is no longer a navigation feature. It is a dependency layer underneath automation, logistics, energy, telecom, finance, data centers, transportation and every nation’s digital economy and critical infrastructure.

The performance requirements for modern and emerging applications are also not abstract. Gambale points out that NAVAC’s 2035 requirements table points to centimeter-class horizontal and vertical accuracy requirements for many high-value applications: 2 to 15 cm for precision irrigation and cultivation, 4 to 6 cm for kinematic survey, and 10 cm for Level 3-and-above road autonomy and collision avoidance. For timing-dependent applications such as the coming 6G and DVB networks, the requirement moves from position into time, with NAVAC citing the need for 10-ns timing accuracy.

A backup that preserves rough continuity may be valuable for some applications. But it is not enough for a port that needs centimeters, a precision agriculture workflow that depends on corrected guidance, or a timing network that needs nanosecond-level synchronization.

In his PNT Leadership Summit presentation, Gambale cites Baltic offshore wind construction and a $5.1 billion Baltic Power project that is essential for Poland’s energy security and independence, including 76 Vestas 15 MW turbines. He also frames offshore construction requirements in hard operational terms: precision construction needs less than 5 centimeters at 3 sigma, 24/7/365, without fail; and ship dynamic position systems (which automatically maintains a vessel’s exact position and heading using its own propellers and thrusters) needs less than 10 centimeters at 3 sigma to work.

In agriculture, Gambale points out, interference does not need to jam an entire operating area to cause disruption. If today’s essential correction infrastructure is vulnerable, the precision layer then collapses.

“In the Ukraine, it’s now become even more trivial to jam a huge area of farmland,” he said. “You don’t have to try to jam the whole area. You just jam the local reference station, and that whole area is toast.”

That observation turns PNT into a food security issue, not simply a navigation issue. A tractor autosteer system, a surveyor, a road construction company, a port crane, an offshore construction vessel and a data center may appear to occupy different markets, but they all share the same dependency: high-confidence position and time.

Gambale’s message is that resilience must be judged against the actual application, not against a generic idea of signal continuity.

Do Not Deploy Your Grandfather’s GPS Backup

One of the strongest lines in Gambale’s presentation was: “Do not deploy your grandfather’s GPS backup.”

It is an intentionally provocative phrase, but the point is technical. Many valuable present-day applications—and most future applications—need high accuracy, high confidence and trusted timing. Systems that provide only low-accuracy continuity do have value for some uses, but they will not keep a modern autonomous port or logistics site, precision agriculture workflow, road construction site or high-value industrial operation running.

ESA’s NAVAC report reaches a similar conclusion from a different angle. It says future PNT will be delivered through a combination of alternative, independent and complementary sources: multiple GNSS in different orbits and frequencies, cellular networks, terrestrial systems such as eLoran, Wi-Fi and signals of opportunity, augmentation systems, inertial sensors, quantum sensors, magnetic sensors, miniature atomic clocks and digital maps. It also concludes that future systems will increasingly operate as “systems of systems” designed to meet the performance required for a given application.

That is very close to Gambale’s “what does your application need?” mantra. A technology is not useful because it belongs to a fashionable category. It is useful if it meets the required accuracy, timing, integrity and resilience for the mission.

And those requirements are getting more difficult, not easier.

NAVAC states that “accuracy is addictive,” that users will demand more robust solutions less susceptible to natural or man-made disruption, and that assured PNT demand will grow tenfold by 2035, including in physically challenging environments such as indoors, multi-story buildings, urban canyons and underground facilities.

That is why Gambale’s critique of low-performance complementary PNT is so sharp. “There is no point deploying technology that gets you three quarters of the way there, and the port is still stopped,” he said.

Positioning Depends on Timing

For Gambale, timing is the most underappreciated part of the PNT discussion. “PNT only exists because of the T,” he said.

That statement is more than a slogan. Positioning systems depend on timing. Digital infrastructure depends on timing. Telecom, financial systems, data centers, power grids, autonomous systems and distributed industrial operations all require trusted time at levels appropriate to their applications.

Taggart makes the same point in institutional terms. His ION Newsletter column notes that, through NIST, the Department of Commerce maintains the nation’s time and frequency standards, while NIST and the U.S. Naval Observatory provide official U.S. precise-time contributions to the Bureau International des Poids et Mesures, which calculates Coordinated Universal Time. He also notes that financial markets, telecommunications services, data networks, electric power grids, pipelines and SCADA services all depend on timing derived from GPS.

For Gambale, that dependency should drive a different standard of performance. He argues the industry too often talks about timing in terms of minimum standards rather than future capability.

“The world isn’t asking for worse timing,” he said. “As you get better and better timing, you get better and better positioning, and better and better digital capabilities. That’s why our Locata team has dedicated several decades of innovation to be able to deliver GNSS-free, sub-nanosecond synchronization and time transfer.”

He explains the issue in terms engineers understand: error budgets. Every system has a set of error sources—timing error, multipath, atmospheric effects, electronic variation, geometry, signal processing limits and more. If timing consumes too much of the error budget, there is less margin left for everything else.

“If the bucket is 75% full of timing error, that leaves them a lot less margin to play with,” Gambale said. “However, if we can reduce that timing error budget down to 10% of the bucket, then they’ve got a lot more leeway with the rest of the error budget.”

That is why he sees timing as a foundation, not a feature. Better timing does not merely improve clocks. It improves the ability to position, synchronize, automate and trust distributed systems.

NAVAC also emphasizes timing. The report states that accurate timing is the critical use case for communications and power distribution networks, and it identifies distributed and networked time-scale infrastructures as an important path toward resilient timing applications independent from GNSS.

Multipath, Trust and the Devil in the Real World

Gambale is equally forceful about multipath, explaining why Locata has spent years creating new technology to mitigate this obstacle. In terrestrial and obstructed environments, reflected signals can become one of the dominant sources of error. It is not enough to say a transmitter is nearby or a signal is stronger. The system must manage reflections, geometry and line-of-sight integrity.

“Multipath is the devil,” he said. “It is everywhere, and unless you deal with it, you will never be able to give an accurate position that’s reliable.”

This is where the conversation then turns from availability to trust.

Jamming denies. Spoofing deceives. Multipath corrupts. Each poses a different challenge. A receiver that produces an answer is not necessarily producing a trustworthy answer. In heavily automated systems, that distinction can become dangerous.

Gambale argues that users have become conditioned to trust the box. The receiver gives a position, and the system accepts it. That worked in an era when GNSS was generally available and interference was occasional. It becomes much more fragile in an environment of persistent jamming and spoofing.

“It’s all about trust,” Gambale said. “Even if GPS comes back, many huge companies no longer want to depend on it, because it is no longer trustworthy.”

That may be the most important transition in the PNT debate. Availability asks whether the signal exists. Trust asks whether the system should act on it.

From AIR to Sovereignty

In the summit presentation, Gambale framed the future of complementary PNT around three validated attributes: Accuracy, Integrity and Resilience—AIR.

Accuracy means the system can meet the application’s actual performance requirement. Integrity means the user can trust the answer, especially in safety-of-life or mission-critical applications. Resilience means the system continues to function—or recovers predictably—under real-world stress. Gambale stated: “Without AIR your application will die!”

Gambale has since added a fourth concept: sovereignty.

For him, sovereignty does not only mean national ownership in a political sense. It means control. Control over the PNT layer that critical systems depend on. Control over the ability to deploy, operate and trust the infrastructure required for the mission. Control over the destiny of an organization, business or site.

Gambale returns repeatedly to the idea that nations and critical infrastructure operators must stop thinking of PNT as an invisible utility that simply arrives from somewhere else. They must treat it as critical infrastructure. Lifeblood for their business.

“Electricity is wonderful,” he said. “It is distributed everywhere. But show me one critical infrastructure site that doesn’t have backup batteries or a generator.”

The analogy is simple and powerful. Critical sites rely on the grid, but they do not trust the grid alone. They build backup capability because the consequences of failure are too severe. Gambale believes PNT now requires the same mindset.

The Spectrum Sandbox

His policy prescription is equally direct: create a terrestrial PNT spectrum framework.

“The best thing that America can do to push real PNT resilience forward is to allocate a terrestrial spectrum for the job,” he said. “Give it a slice of spectrum that everybody can play in, if they wish.”

For Gambale, this would create a sandbox for innovation. Satellite systems have protected spectrum. Terrestrial PNT, if it is to become a serious resilience layer, needs a comparable policy foundation. Within that framework, industry, universities and government could build and test systems designed for specific application requirements.

“Allocate spectrum just like the satellites have got spectrum,” he said. “Allocate a terrestrial capability where you can determine what’s required for each application in an area. But give us the sandbox. Then let 1,000 innovations bloom, as was the case in the early days of GPS.”

That argument moves the discussion beyond individual products. It treats PNT resilience as an ecosystem problem. If the United States—or any sovereign nation—wants local, high-confidence PNT capability, then the nation must create the conditions for such systems to exist.

It also fits the broader direction of PNT architecture. NAVAC’s 2035 vision does not imagine one replacement for GNSS. It imagines combinations of systems: space-based, terrestrial, cellular, augmentation-based and sensor-based. It also warns that alternative systems must avoid hidden dependencies on GNSS itself, such as using GNSS as the time reference for supposedly independent ground networks, or as an essential reinitialization of an IMU system.

That warning is central to the Gambale thesis. A backup that depends on the system it is backing up is not a true replacement. A resilience layer that fails under the same conditions as GNSS may add complexity without adding survivability.

Gambale sees the spectrum sandbox as a chance not merely to protect infrastructure, but to create the next exportable PNT architecture.

“If America does it first, and you have all of your bright minds, and the universities, Silicon Valley, and everyone throws some real effort at it, you can do exactly what you do with GPS,” he said. “You can export it all over the world again.”

Then came the line he delivered with a laugh, but not entirely as a joke:

“Make PNT great again.”

The phrase works because the argument underneath it is serious. GPS was one of the United States’ greatest contributions to the modern world. It enabled entire industries. It created enormous civilian and commercial value. But the dependence it enabled has also become a 21st-century infrastructure vulnerability.

As Gambale put it: “The U.S. nation in the 1990s gave the world one of the greatest gifts of all time. That gift has now created one of the biggest problems for the 21st century. That problem must be solved. And Locata has created exceptional new high-accuracy technology that does not depend on GNSS at all. It delivers a level of control and sovereignty that will certainly be part of the ‘future of PNT.’”

For ports, farms, offshore energy projects, logistics hubs, construction sites, autonomous systems and critical infrastructure operators, the need for a solution—for AIR, for control and for sovereignty—is no longer theoretical. The jamming and spoofing environment is real and escalating. The performance requirements are not abstract. And the dependency on a signal that was never designed to carry this much weight is not going away on its own.

That is the state of play. 

The post The New PNT Reality appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

For decades, timing has been the least visible element of positioning, navigation and timing. Positioning and navigation tend to draw the operational attention. Timing sits deeper in the architecture, synchronizing networks, aligning systems and enabling the data flows modern missions require. But in contested environments, where GNSS signals can be jammed, spoofed or lost, timing is no longer a background utility. It becomes a measure of resilience.

That is the market Oscilloquartz is addressing. The company has more than 75 years of timing heritage and a long record in telecom synchronization, but its current strategy is aimed at a defense market that is beginning to treat trusted time as a core requirement for resilient PNT.

Gil Biran, who leads Oscilloquartz, describes the company’s position directly. “We are the timing enabler for any PNT mission-critical defense network,” he said. That statement reflects both technical confidence and strategic ambition. Oscilloquartz wants to be understood not simply as a supplier of clocks, but as a provider of timing architectures for defense users operating in degraded and contested environments, including mobile deployments.”

The shift builds on the company’s experience in mobile networks. When Biran took over the business after its acquisition from the Swatch Group, Oscilloquartz had lost ground in what had become one of the most demanding timing markets. The company refocused on systems rather than components and built an NTP and PTP portfolio around the synchronization needs of mobile operators. Oscilloquartz, Biran said, moved from roughly 20% share in mobile operators globally to about 80%.

That experience matters because telecom forced the company to solve timing as a network problem with accuracy that was measured in nanoseconds. Mobile operators needed synchronization at scale, across large distributed networks, with high availability, resiliency and standards-based performance. Defense users need many of the same fundamentals, but under more severe conditions.

FROM TELECOM SYNCHRONIZATION TO DEFENSE TIMING

“The foundational requirements for PNT are the same across mission-critical networks, whether it’s a mobile operator, power utility or defense organization,” Biran said. “Now, we have to focus on the differences.”

Those differences are significant. In telecom, timing equipment is generally installed in fixed sites. In defense, timing has to operate across ground, airborne, maritime and mobile applications. Systems may be mounted in vehicles, deployed in command centers, integrated into shelters, placed on platforms or connected to legacy infrastructure.

Biran identifies two immediate translation points from telecom to defense: physical interfaces and ruggedization. Defense networks retain large amounts of legacy infrastructure, and timing systems must connect to what is already fielded. “Defense is all about legacy,” he said. “It’s all about equipment that is sitting there for tens of years, and nobody’s going to touch.” To participate in those architectures, Oscilloquartz has had to support specialized physical interfaces that are uncommon in commercial telecom networks.

The second requirement is ruggedization. “In the telecom space everything is on the ground, everything is in a fixed location,” Biran said. “When you move to defense, you have ground applications, you have airborne applications, you have maritime applications, and now in most of these applications you are on the move.” That reality is behind the launch of the ruggedSync™ Series OSA 5510, which Biran describes as a rugged clock unit designed to bring Oscilloquartz’s timing capabilities into defense environments without rebuilding the entire product concept.

The deeper defense requirement is not only rugged hardware. It is trust.

For years, many timing architectures treated GNSS as the primary source and internal oscillators or network references as backups. Biran argues that this model no longer fits the threat environment. “The primary is GNSS,” he said. “Why set the least reliable source as the primary? That was good for the old days, not today.”

ZERO-TRUST TIMING IN A GNSS-DENIED WORLD

That observation leads directly to Oscilloquartz’s view of zero-trust timing. In practical terms, zero trust means no single timing source is accepted without evaluation. A defense node should be able to compare multiple timing inputs, assign different levels of confidence to each source depending on its reliability, detect anomalies and continue distributing trusted time. The issue is not whether GNSS remains useful. It does. The issue is whether the architecture depends on GNSS as an unquestioned authority.

“Every node in the network should have as many as possible sources, and the focus should be on diversified sources,” Biran said. In that model, GNSS may be one input, but it is not the only one. Other sources may include LEO-based timing, terrestrial RF sources, NIST references, PTP, White Rabbit and local atomic clocks. Biran compares the architecture to a recipe in which different sources receive different weights according to their reliability. Cesium, because it does not depend on an external signal, carries a different weight than a satellite signal that can be denied or manipulated.

This is where Oscilloquartz sees cesium and optical pumping as central to defense timing resilience. Holdover is often discussed as a clock specification, but in defense it is better understood as the last line of defense. If a system can maintain trusted time after GNSS is lost, it can continue operating. If it cannot, the network and the mission begin to degrade.

Biran points to submarines as a clear example. “Why do submarines need the cesium clock? Because if you’re underwater for two months, you will not know where you are unless you have a reliable, accurate clock source,” he said. The same principle extends beyond the undersea domain. As defense systems become more mobile and as GNSS denial becomes more common, the ability to maintain time without external reference becomes a strategic capability.

Oscilloquartz has invested in optical pumping technology for cesium clocks for much more than a decade, work Biran links to both performance and size. He said the company can hold 100 nanoseconds for up to 150 days, a figure he contrasts with rubidium-class holdover at far shorter durations. “Even if GNSS will disappear for six months, we can still maintain the mission critical network with this level of accuracy,” he said. He also makes clear that this is not only about duration. Airborne and mobile systems impose constraints on size, weight and stability under vibration. “You have lasers inside the box,” Biran said. “How do you make sure that the laser is stable enough when the unit is moving, is under vibration? This is not a simple challenge.”

The larger point is that defense organizations should not think about timing as a collection of individual devices. They need to think about time as a distributed system-level resource. A high-stability core clock is important, but it is not enough. Trusted time has to move across networks, reach edge nodes, be monitored, compared, managed and protected.

“Our solution is not just a box,” Biran said. “It’s a networking solution.” He points to White Rabbit technology as one path for distributing high-accuracy timing over fiber, and to management systems that allow operators to see and control timing across the network. In a contested environment, that visibility matters. Operators need to know which sources are available, which nodes are degraded, where timing quality is changing and when the system has shifted into holdover.

ASSURED TIME AS A NETWORK ARCHITECTURE

The company is also watching a broader shift toward distributed timescale solutions. Historically, national timing could be delivered from a small number of sites. That model becomes harder as users need tighter timing closer to the mission. “You need to bring the time scale source close to the customer,” Biran said. He sees defense organizations moving toward more localized time sources, including service-level or agency-level timescales that can support operational networks without depending entirely on distant infrastructure.

For Oscilloquartz, the technical strategy is now being matched by a go-to-market shift. Biran is direct about the distinction: selling into defense is not the same as selling into telecom. The company has added sales talent with defense-sector experience, expanded its U.S. channel through representation firms focused on defense markets, and is building out value-added reseller relationships with defense expertise in EMEA and APAC. The customer path is different as well.

“We are not selling the full defense solution,” Biran said. “We are providing the timing that enables these vendors and system integrators to provide a full end-to-end defense solution.”

That distinction is important for the U.S. DoD market. Timing is rarely purchased in isolation. It is specified into systems, integrated into platforms and evaluated as part of larger mission 
architectures. Oscilloquartz’s near-term task is therefore as much educational as commercial. It must show defense users that the “T” in PNT is not a supporting detail. It is a foundation for network resilience, autonomy and operational continuity.

How will Oscilloquartz know it has succeeded? Biran points to revenue mix, defense leads, pipeline growth and program wins. The company, he said, has already won major defense projects, including in the United States, though he does not name them, due to the confidential nature of the business. The broader milestone will be market recognition: when Oscilloquartz is seen not only as a telecom synchronization company, but as a global defense timing provider.

For defense users, the underlying issue is clear. GNSS will remain essential, but it cannot be the only trusted source of time. The next phase of PNT will depend on architectures that can evaluate, preserve and distribute time even when the external environment is compromised. Oscilloquartz is betting that its telecom-scale experience, rugged timing portfolio, cesium technology and zero-trust approach position it for that shift.

In Biran’s words, “The baseline is to have the right solution.” In defense timing, that baseline is moving quickly from accurate clocks to assured and resilient time.

The post The “T” in Contested PNT appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

The milestone is notable for being free-space rather than fiber-based, a distinction the company says is a critical step toward operational deployment in environments where physical infrastructure is unavailable.

The fully integrated Ares terminal is designed to combine 10 Gbps free-space optical communications, entangled photon distribution for timing and encryption key sharing, and a stable clock ensemble disciplined by Xairos’ Quantum Time Transfer technology. The system targets RF- and GPS-denied environments, and the company has cited precision synchronization for distributed sensors and antennas — including applications relevant to Golden Dome-style architectures requiring geolocation and data fusion for fire control — as representative use cases.

The announcement follows Xairos’ completion last week of Phase 1 of the UK’s £1.4 million Innovate UK Quantum PNT Mission under the TimeLink programme, which advanced the company’s Athena product line for GNSS-independent timing in critical infrastructure. The company is also the technology provider for the Colorado Quantum Incubator’s planned national quantum timing testbed, announced in April. Next steps for the Ares terminal include further development under the Colorado Quantum Incubator’s Quantum Timing Center program.

The post Xairos Completes Free-Space Quantum and Optical Timing Demonstration appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

Twenty years on, Galileo stands as both a major European achievement and a hard-won lesson in what it takes to build sovereign, resilient and globally relevant navigation infrastructure. Hein will examine the decisions, compromises and challenges that shaped the system, offering readers a rare behind-the-scenes perspective on Europe’s strategic choice to move from dependence to capability—and why that story still matters now.

Highs and lows in the development of the European Satellite Navigation System, Galileo. 

For much of the late 20th century, the world had access to only one fully operational global satellite navigation system: the United States’ Global Positioning System (GPS). Conceived in the 1970s as a military asset and declared fully operational in 1995, GPS had by the mid-1990s become indispensable to civilian users worldwide—from pilots and ship captains to farmers, surveyors and ordinary motorists. Yet, beneath the convenience of free, open signals lay a profound strategic vulnerability: GPS was owned, operated and controlled exclusively by the United States Department of Defense (DoD). Washington could, in principle, degrade or deny the signal at will.

This dependency troubled European policymakers and military planners throughout the 1990s. The concern was not merely theoretical. During the Gulf War of 1991, the United States deliberately degraded GPS accuracy through a technique known as Selective Availability, limiting civilian precision to roughly 100 meters. Although Selective Availability was switched off in May 2000, the capability to reinstate it remained. European governments, aerospace industries, and transport authorities recognized that building critical infrastructure—aviation, rail, maritime, precision agriculture, financial timing networks—on a foreign-controlled system was a risk that strategic autonomy could not tolerate.

Early Studies and the Political Will to Act

European interest in an independent navigation capability had simmered since the 1980s. The European Space Agency (ESA) had developed NAVSAT and GRANAS concept studies, and various national programs explored augmentation systems. A concrete step came with the European Geostationary Navigation Overlay Service (EGNOS), developed jointly by ESA, the European Commission (EC), and Eurocontrol from the mid-1990s. EGNOS, which became operational in 2009, could improve GPS accuracy and provide integrity signals for safety-critical applications, but it remained dependent on the underlying GPS constellation. It was a patch, not a solution.

The decisive political turn came in the second half of the 1990s. The European Commission’s 1999 communication, “Galileo: Involving Europe in a New Generation of Satellite Navigation Services,” laid out the case openly: Europe needed its own system, civilian-controlled and commercially oriented, interoperable with GPS but independent of it. The name Galileo, a tribute to Galileo Galilei, an Italian astronomer who made foundational contributions to the science of motion and observation, was chosen to signal both scientific heritage and a new era of European technological ambition. (I believe Kepler would have been the better name. But politics had decided, not technology!)

The Early Days of Galileo: 1999-2000 Political Launch and National Ambitions

The story of Galileo’s political birth is, in many respects, the story of a European pilgrimage. This was the first generated “income” of Galileo: however, not for the space system but for the Galileo Travel Agency! In 1999 and 2000, delegations, lobbyists, industry representatives, and national officials from across the continent converged on Brussels with a shared ambition but—as would quickly become apparent—with rather different ideas about what that ambition should deliver. The atmosphere was one of excitement tinged with opportunism: here was a major program taking shape, and every stakeholder wanted a seat at the table. 

The process generated what insiders sometimes called national “wish lists”—catalogues of desired outcomes, preferred industrial workshares, and projected economic benefits that each member state hoped to extract from the new system. These lists were gathered under various headings and studies. The Galileo Overall Architecture Definition (GALA) study was among the most prominent. GALA was intended to define the overall system architecture, but it also became a vehicle through which competing national interests were channelled into the technical debate. The result was a negotiating process as much as an engineering one.

The official justifications advanced for building Galileo were numerous and, on close inspection, of uneven quality. Safety of life, employment creation, industrial spin-offs, enhanced road and rail navigation, search and rescue improvements, integrity, public-private partnership—all were cited, sometimes with statistics that did not survive scrutiny. Several of the arguments were, frankly, either misconceived or greatly exaggerated, and those with a critical eye could see the economic forecasts in particular owed more to political necessity than to rigorous analysis. The need to justify a multi-billion-euro public investment demanded a compelling narrative, and not every element of that narrative was equally well-founded.

Beneath the rhetoric, however, two motivations stood out as genuinely sound. The first was the desire to break the GPS monopoly. At the turn of the millennium, the entire world depended on a single navigation system owned and operated by the United States DoD. The vulnerabilities this created—strategic, commercial and operational—were real, and no amount of goodwill between allies could fully substitute for an independent capability. The second motivation was equally clear-eyed: Galileo was to be Europe’s ticket into the front rank of high-technology infrastructure. Satellite navigation was not merely a useful service; it was becoming the invisible foundation of the digital economy, and Europe’s long-term competitiveness depended on being a provider rather than merely a user of that foundation. These two reasons, strategic independence and technological leadership, were, in the end, the ones that mattered, and they were sufficient.

An American colleague told me: “I thank Europe for the decision to build up its own satellite navigation system: This was the best investment in GPS. We have never seen so many improvements in GPS after a while of stagnation.”

The Lisbon Treaty and European Space Governance

Before continuing the discussion about the early days of Galileo, I must mention an important political move of the European Union (EU) and its Member States. The Lisbon Treaty, which entered into force in December 2009, marked a turning point in European space governance by providing, for the first time, an explicit legal basis for space activities at the Union level. The key instrument is Article 189 of the Treaty on the Functioning of the European Union (TFEU), which authorizes the EU to develop a European Space Policy aimed at promoting scientific and technological progress, strengthening industrial competitiveness, and supporting the implementation of broader Union policies.

On this basis, the EU may establish a European Space Programme and adopt the necessary legislative measures (regulations, directives and decisions) through the ordinary legislative procedure. In terms of the division of competences, however, space occupies a carefully circumscribed position. Although it falls within the category of shared competences, it is in practice treated as a “support or coordination competence.” The Treaty explicitly prohibits the harmonization of national laws and regulations, preserving the legislative autonomy of Member States in the field.

The Treaty recognizes the security and defense dimensions inherent in space activities. Because space infrastructure is frequently dual-use in nature, serving both civilian and military purposes, the Treaty permits, and in certain respects requires, the EU to address these dimensions as part of a comprehensive space policy. This provision has taken on growing practical significance as Europe’s dependence on space-based services for defense, border management, and crisis response has deepened.

Finally, the Treaty also mandates that the Union establish appropriate relations with the ESA, acknowledging ESA’s longstanding role as Europe’s principal space organization and the need for coherent institutional cooperation between the two bodies.

The Treaty also codifies, at least implicitly (and theoretically), a division of labor between the EU and ESA that has evolved over decades of institutional practice. The EU concentrates on space policy, program funding, and the demand side of the equation, defining what services are needed and ensuring they are delivered to users. ESA, by contrast, remains primarily responsible for the supply side: the engineering, infrastructure, and technical development that make those services possible. The two organizations should be complementary rather than competing.

My impression is the ESA underestimated the implications that were arising over the following years and remained silent. At first glance, it seems quite natural for the EU to be responsible for space policy, taking up the needs of the European community and preparing funding for space activities, while the ESA takes responsibility for technical realization. Unfortunately, the boundary between their respective roles has not always been free of friction and has led many people to a perceived disempowerment of ESA in some directories. I will later come back in detail what is meant with this statement.

One of the Treaty’s most consequential constraints is precisely what it does not permit. The EU has no power to impose harmonized space regulations on its Member States: national space law remains firmly within the sovereign remit of each country. This limitation reflects the broader constitutional settlement of the Lisbon Treaty, which sought to expand Union competence in space while simultaneously protecting the regulatory independence of member governments. The practical effect is a patchwork of national licensing regimes and liability frameworks sitting alongside, but not superseded by, European-level policy. In fact, one can still observe space activities in the Member States, which are duplicating efforts of the EC or even competing by building up similar satellite navigation or satellite communication systems.

Since 2009, the EU’s engagement with space has also acquired a markedly more security-oriented character. The dual-use nature of space infrastructure—navigation, Earth observation, and satellite communications all serving both civilian and defense purposes—has increasingly drawn space policy into the orbit of broader strategic autonomy debates. Protecting European space assets from jamming, spoofing, cyber intrusion, and anti-satellite threats has moved from the margins to the mainstream of EU space thinking, reflecting a wider recognition that space is no longer a benign domain but a contested one in which Europe’s ability to act independently depends on the resilience and security of its own infrastructure.

According to its convention, the ESA is limited to “exclusively peaceful purposes.” However, under pressure from the EU, this term has increasingly been interpreted to also allow for “defensive” military aspects (e.g., surveillance or encrypted communications).

The Decision to Build Galileo

The formal decision to proceed with Galileo was taken by the European Council in March 2002, when EU transport ministers gave their approval for the development and deployment phase of the system. This followed years of preparatory studies, feasibility assessments, and political negotiation, and it represented a definitive commitment by the Union to invest in an independent satellite navigation capability. The EC and the ESA were tasked with jointly overseeing the program, with ESA taking the lead on the technical and procurement side while the EC held overall political authority. A dedicated management structure, the Galileo Joint Undertaking, was established in 2002 to coordinate the two institutions and to manage the program’s early phases.

Costs and Funding

The original cost estimates for Galileo were, in retrospect, optimistic. The development and in-orbit validation phase was initially budgeted at approximately €1.1 billion, with overall deployment costs for the full constellation estimated at around €3.2 billion. These figures reflected the assumptions of the early 2000s, including the expectation that a substantial share of the funding would come from private industry through a public-private partnership (PPP) model. Under this model, a private concession holder was to operate the system commercially and recover costs through service revenues, with public funds covering only a portion of the investment.

I live in a town south of Munich. At the same time as the Galileo decision, a family-owned pharmaceutical company that produced generic medical drugs and had about 100 employees was sold to a multinational medical company for more than 6 billion Euro—just two Galileo systems (cost assumption early 2000s)!

Civil Control, Military Reality and the Question of Dual Use

One of the most deliberate and politically significant design choices made for Galileo was the insistence that it be a civilian system under civilian control. This was not merely a technical or administrative detail; it was a statement of principle, and it was intended to distinguish Galileo fundamentally from GPS. The United States’ system had been conceived as a military asset, and its civilian use, however widespread, remained conditional on the goodwill of the U.S. DoD. Galileo, by contrast, was to be governed by the EC, a civilian institution, and its primary purpose was defined in terms of civilian applications: transport, agriculture, timing, search and rescue, and commercial services.

This civilian identity was not, however, synonymous with exclusion of the military. European policymakers were candid from the outset that defense and security forces would be entitled to use Galileo signals, including the encrypted Public Regulated Service (PRS) reserved for government-authorized users. The formulation that became standard in policy documents was straightforward: Galileo is a civil system under civil control, and the military may use it. This formula allowed Europe to maintain its civilian branding while acknowledging the inescapable reality that any global navigation system is of strategic value, and that European armed forces and security agencies would naturally make use of a European system. 

What happens to the civil control of Galileo in times of crisis? Most European Member States have a Radionavigation Plan that makes clear that, when it comes to the crunch, the military has the final say. The tension between Galileo’s civilian identity and the realities of national security has therefore never been fully resolved; it has merely been deferred.

The PRS was conceived as a government-controlled, encrypted service for authorized institutions—customs agencies, specialized police units, border control, and similar bodies—with strictly limited access. Some nations, however, lobbied for PRS access to be extended to fire brigades and other local emergency services, apparently overlooking the fact that the number of simultaneous users the system can support is not unlimited, and a large number of users might create a problem for security. The military, meanwhile, was not explicitly named among the intended users—the working formula remained the familiar one: they may use it—even though the PRS was developed to a specification, and at a cost, that closely mirrors a military-grade service. The omission was not accidental; it reflected the political sensitivity of departing too visibly from Galileo’s declared civilian character.

Adding a further layer of complexity, most European nations had already concluded Memoranda of Understanding with the United States for the use of GPS, particularly within the NATO framework. Against that background, Galileo’s PRS was initially regarded by many European military establishments as superfluous—a costly duplication of a capability they already accessed through their American alliance commitments.

The world has changed substantially since those early design decisions were made. The conflicts and wars of recent years and today have made clear Europe can no longer take its security for granted and must rebuild defense capabilities that were allowed to atrophy significantly after the end of the Cold War. In that context, an independent, European-owned global satellite navigation system such as Galileo is plainly a major strategic asset for modern defense—essential for the guidance and operation of aircraft, naval vessels, armoured vehicles, and precision weapons alike. 

It is, therefore, even more remarkable that Galileo has not yet been officially designated as a dual-use GNSS. Every other global and regional satellite navigation system—GPS, GLONASS, BeiDou, NavIC—carries an explicit dual-use status. Galileo’s continued omission from that category is increasingly difficult to justify, and the argument for formally recognizing what has always been true in practice grows stronger with every passing year.

A further technical observation is warranted in the context of the PRS. Given that the PRS encryption is not watertight, the signal can be tracked without knowledge of the access code, so-called codeless tracking. One is therefore entitled to ask: What is the justification for the extraordinarily expensive and complex national access key schemes, which differ from country to country? I hope the second generation of Galileo will overcome that problem.

Opening Galileo to the World: International Partners

From an early stage, the EC pursued an active strategy of inviting third countries to join Galileo as partner nations and stakeholders. The rationale was partly financial—contributions from partner countries would help share the costs of development—and partly strategic. A system with broad international participation would be more difficult to challenge or marginalize, and would generate a larger global user base, strengthening the commercial case for European industry.

China was among the earliest countries to engage substantively with the program: A cooperation agreement with the Chinese government was signed in 2003, and China initially contributed funding and participated in technical working groups, though its involvement later diminished as Beijing’s own BeiDou navigation system matured. Israel signed a cooperation agreement with the EU in 2004, becoming one of the first non-European partners to formalize its engagement with the program. Ukraine, Morocco and South Korea also concluded first political agreements in the mid-2000s, each bringing different motivations—industrial participation, regional positioning, or access to high-accuracy services. However, it did not come to the second agreement defining the operational engagement in Galileo. India entered into discussions with the EU during the same period, reflecting the interest of major spacefaring nations in securing a stake in the emerging global navigation landscape. 

Together, these early partnerships gave Galileo an international footprint from the outset and underscored the EC’s ambition to build not merely a regional system, but a genuinely global one. 

PROF. DR.-ING. HABIL. DR. H. C. GÜENTER W. HEIN, Emeritus of Excellence at Bundeswehr University Munich, draws on more than two decades of first-hand experience to recount the development of Galileo, the European satellite navigation system. His involvement began with national research conducted between 1995 and 2008 at his former Institute of Geodesy and Navigation at Bundeswehr University Munich, funded by the Deutsches Zentrum für Luft- und Raumfahrt (DLR, German Aerospace Center). From 2000 onwards, he represented Germany in various EC Galileo study groups, including the Galileo Signal Task Force, and took part in the EU-US negotiations on GPS/Galileo interoperability from 2000 to 2005. He subsequently joined the European Space Agency as Head of the EGNOS and Galileo Evolution Programme Department from 2008 to 2014. He later served as a member of the Executive Board of Munich Aerospace e. V. and has provided consultancy to leading European satellite navigation companies. Güenter W. Hein is the founder of the Munich Satellite Navigation Summit and the Munich New Space Summit, which were merged in 2026 to form the Munich Space Summit. Through all these roles, he has played a central part in shaping European satellite navigation over the past 20 years.

The post Inside Galileo: Europe Decides to Build Up its Own Global Satellite Navigation System appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

This capability is increasingly critical as data centers and 5G virtualized Radio Access Networks build deeper dependencies on satellite-based timing.

The modules support automatic source selection and locking across GNSS, Synchronous Ethernet (SyncE), and Precision Time Protocol (PTP), switching between sources without disrupting timing continuity. That flexibility is central to the design intent: in infrastructure environments where timing failure cascades quickly into service degradation, the ability to transition seamlessly from GNSS to a secondary source — and hold position during that transition — is the operational requirement the module is built around.

When GNSS signal is lost, onboard Oven Controlled Crystal Oscillators maintain holdover for up to eight hours depending on variant. The MD-990-0011-BA01 provides four hours of holdover performance; the MD-990-0011-BC01 extends that to eight. Both integrate a SyncE synthesizer with dual independent Digital Phase-Locked Loop channels, a temperature sensor, EEPROM for board configuration, and a low-jitter oscillator in a single plug-in form factor.

Developed in collaboration with Intel, the modules are designed for compatibility with Intel Xeon 6 SoC-powered server platforms, supporting OEMs and ODMs building next-generation infrastructure for distributed workloads and real-time applications. Both variants are available now in production quantities through Microchip direct sales and authorized distributors.

The post Microchip Timing Module Addresses GNSS Holdover for Data Centers and 5G Networks appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

The satellite had reached its 10-year design life on March 10. ISRO indicated the spacecraft will remain operational for limited services, including one-way messaging, but it will no longer support standard navigation functions that depend on precise onboard timing.

Timing loss directly impacts PNT performance

Atomic clocks are the foundational element of any GNSS or regional PNT system. Navigation signals rely on nanosecond-level synchronization between satellites and user receivers; without a stable onboard clock, a satellite cannot provide accurate ranging. In practical terms, the loss of IRNSS-1F as a timing node reduces usable signal geometry and degrades overall system robustness rather than simply removing a satellite from inventory.

IRNSS-1F was launched in March 2016 as part of the original IRNSS constellation, now branded as NavIC. Its loss for navigation further compresses a system already operating with limited redundancy. Public disclosures and recent reporting indicate that only a subset of NavIC satellites are currently fully usable for positioning services, leaving less margin for fault tolerance across the regional coverage area.

Persistent clock reliability challenges

The latest failure reinforces a long-standing issue within the NavIC program: the reliability of space-qualified rubidium atomic clocks. Earlier IRNSS satellites experienced similar failures, forcing ISRO to operate the constellation conservatively and accelerate plans for replacement spacecraft. Across GNSS architectures, clock reliability is a critical determinant of system availability—satellites can remain on orbit yet become functionally irrelevant for navigation if timing degrades.

ISRO has been pursuing second-generation NavIC satellites to restore and expand capability, but progress has been uneven. The NVS-02 satellite, part of this next-generation effort, encountered issues following launch despite successful orbital insertion. At the same time, ISRO continues to invest in the broader timing infrastructure supporting NavIC, including international metrology collaborations aimed at strengthening reference time systems.

Strategic implications for sovereign PNT

The immediate effect is not a loss of NavIC service, but a reduction in resilience at a time when sovereign PNT capability is increasingly treated as critical infrastructure. NavIC was designed to reduce India’s reliance on foreign GNSS for both civilian and government applications. As jamming, spoofing and geopolitical risk reshape the PNT landscape, constellation health—particularly onboard timing integrity—becomes a primary measure of operational capability.

Timing integrity remains the system’s linchpin

The IRNSS-1F failure underscores a fundamental point: end-to-end resilience begins with stable space-segment timing. Advances in signal structure, augmentation and receiver design cannot compensate for degraded clocks in orbit. Restoring NavIC’s full capability will depend not only on replenishment launches, but on achieving durable, next-generation clock performance across the constellation.

The post NavIC Clock Failure Trims India’s Regional PNT Capacity appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

It will distribute highly accurate time signals from atomic clocks over terrestrial networks as a complement and backup to space-based systems. 

Terrestrial timing to complement GNSS

Announced by the Department for Science, Innovation and Technology, the investment will support the next phase of the NTC programme, led by the National Physical Laboratory (NPL). Two dedicated sites equipped with advanced atomic clocks will generate an independent national time scale and distribute it via fibre and satellite links, providing a terrestrial timing source alongside GPS, Galileo and other GNSS constellations. 

The government’s statement frames the goal clearly: reduce the UK’s reliance on satellite-delivered timing that can be “targeted and disrupted,” and ensure that critical services – including telecom networks, online banking, transport systems and emergency services – continue to function even during GNSS outages. 

Free timing over air, internet and fibre

A key feature of the NTC build-out is wide distribution. The timing signal will be provided free over the air, via the internet and through fibre networks, giving operators multiple ways to access resilient time. 

When existing timing sources fail or are degraded, the NTC infrastructure is intended to act as a safety net for “vital digital infrastructure,” from mobile base stations and financial trading platforms to energy networks and data centres. 

According to NPL, the programme is also designed to support emerging high-precision, low-latency applications such as 5G/6G networks, smart cities and connected autonomous vehicles, all of which require tightly synchronised time across distributed nodes. 

GNSS vulnerability and economic stakes

The timing expansion is explicitly framed as a resilience measure against GNSS disruption, an issue that has moved steadily up the risk agenda for PNT professionals. The UK government notes that satellite signals can be deliberately jammed or spoofed, and that an extended outage affecting timing-dependent services could cost the UK economy on the order of £1.4 billion in just 24 hours. 

Those concerns echo a wider international debate. Recent analysis has highlighted both accidental incidents – such as the 2016 GPS timing anomaly – and deliberate interference, including Russian jamming of GNSS signals in and around the Ukraine conflict, as evidence that “single-string” reliance on space-based timing is no longer acceptable for critical infrastructure. 

In that context, the NTC’s terrestrial time distribution looks less like a niche scientific project and more like a national security and economic continuity measure, similar in intent to work on eLoran, portable atomic clocks and distributed time networks in other countries. 

Atomic clocks, supply chain and skills

Beyond the network itself, a portion of the £180 million will go into the UK timing ecosystem: supporting domestic supply chains for critical timing components and expanding the skills base in precision timekeeping. 

The NTC programme will fund training for graduates, apprentices and PhD-level specialists, reflecting the fact that resilient timing is becoming a cross-cutting requirement for telecoms, finance, energy, transport and quantum technologies. 

That emphasis on both hardware and human capital is notable. GNSS timing remains central, but as more infrastructure operators move to “multi-source” architectures – combining GNSS with disciplined local oscillators, terrestrial time feeds and holdover strategies – the availability of in-country expertise and trusted components becomes a competitive and security factor in its own right.

What it means for the PNT community

For the global PNT community, the UK’s move is another concrete example of a GNSS-heavy economy investing in terrestrial timing as a first-class utility rather than a backup of last resort.

Key implications:

• Critical infrastructure operators in the UK can plan around a nationally supported, standards-based terrestrial time source instead of building bespoke solutions in isolation.
• The programme reinforces the shift toward layered PNT resilience, where GNSS is complemented by terrestrial timing, local atomic clocks and, potentially, other alternative PNT (A-PNT) technologies.
• By putting significant funding behind NPL and the NTC, the UK is signalling that precision timing is not just a scientific capability but a strategic asset, on par with national compute resources and secure telecoms. 

The development is a reminder that timing, not just positioning, is now driving major infrastructure decisions. As more countries pursue similar investments, the interplay between satellite time transfer and terrestrial time distribution is likely to become a central theme in PNT architecture and policy debates over the rest of the decade.

The post UK Invests £180 Million in National Timing Centre to Back Up GNSS appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

DARPA has outlined new details of its Robust Optical Clock Network (ROCkN) program, describing how high-precision optical clocks could allow U.S. forces to retain GPS-grade positioning, navigation and timing (PNT) in contested environments while also enabling timing precision well beyond what space-based GNSS currently provides. The agency’s latest update, released March 2, emphasizes GPS-free operations for platforms and networks operating under jamming, spoofing or prolonged signal outages. 

Modern missiles, sensors, aircraft and artillery all depend on the nanosecond-accurate timing disseminated by GPS satellites. A timing error of just a few billionths of a second translates into position errors on the order of a meter or more, which can quickly degrade weapon accuracy and sensor coherence. Despite hardening measures, the space-to-ground link remains vulnerable to electronic attack and interference, making assured timing one of the central challenges for GNSS-dependent forces. 

ROCkN Pushes Optical Clocks From Physics Labs Into Tactical Form Factors

ROCkN’s answer is to push optical-domain timing out of the lab and into tactical-grade hardware. The program is developing two classes of clocks: a compact, shoebox-sized unit with power consumption comparable to a household lightbulb, designed to hold GPS-level timing (sub-nanosecond precision) for up to two weeks without any satellite updates; and a larger, “washing-machine”-sized master clock intended to provide a regional time reference with GPS-level precision for more than six months without resynchronization. Both clocks are being engineered under strict size, weight and power constraints for deployment on mobile or forward-based platforms. 

At the network level, ROCkN is also demonstrating over-the-air optical time-transfer techniques that push beyond GPS’ few-nanosecond accuracy. According to DARPA, recent field tests have achieved femtosecond-level synchronization over hundreds of kilometers and have operated multi-node clock networks in challenging weather, from tropical humidity to heat waves and blizzards. Moving from nanosecond to picosecond-and-better timing is expected to unlock new capabilities in distributed sensing, coherent radar and electronic warfare, as well as wideband, high-capacity communications.

Femtosecond-Level Synchronization Targets Next-Gen Sensing, EW and Comms 

The most immediate impact is in timing resilience. Optical clocks with weeks- to months-long holdover effectively create local and regional “mini-time scales” that can maintain GPS-equivalent performance through prolonged outages or deliberate interference. In practice, that means platforms and sensor networks could retain precise time tags and navigation solutions even when denied access to GPS, and could re-align with space-based systems once signals become available again. DARPA also highlights the potential for coherent synthesis of data from multiple compact, mobile sensors at frequencies beyond X-band, improving emitter geolocation and target characterization in contested spectrum. 

DARPA reports that ROCkN hardware has already been flown on fixed-wing aircraft, integrated on ground vehicles and deployed at sea for a three-week demonstration aboard a naval vessel operating in the Pacific. Over the coming year, the agency plans a series of field exercises showcasing ROCkN-enabled capabilities across next-generation PNT, electronic warfare and ISR mission sets, alongside a pilot-line manufacturing effort aimed at supplying Department of Defense transition partners. 

Taken together, ROCkN positions optical-clock-based timing as a key pillar in the broader push toward alternative and complementary PNT. For GNSS users and system designers, it underscores a strategic shift: from relying solely on space-borne signals for timing, to a hybrid model in which resilient, GPS-independent local time sources and optical time-transfer networks backstop – and ultimately extend – the performance envelope of satellite navigation.

The post DARPA’s ROCkN Program Targets GNSS-Free Precision Timing in Contested Environments appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

JUDAH LEVINE, UNIVERSITY OF COLORADO, PASCALE DEFRAIGNE, ROYAL OBSERVATORY OF BELGIUM, ILARIA SESIA, ITALIAN METROLOGY INSTITUTE, GIULIO TAGLIAFERRO, INTERNATIONAL BUREAU OF WEIGHTS AND MEASURES, MICHAEL WOUTERS, NATIONAL MEASUREMENT INSTITUTE

Coordinated Universal Time (UTC) has been recommended as the unique time scale for international reference time stamps and is the basis for civil time in most countries [1]. Time zones, which are established by local administrations, are defined by an offset from UTC. Some applications are required to use time stamps based on UTC either by regulation or by statute [2-4]. There are advantages to the use of time stamps based on UTC, even when it is not required to do so, because this facilitates combining data from multiple sources or when international coordination is important.

Time signals from global navigation satellite systems (GNSS) are widely used as the reference time in many applications, and it is important to understand the requirements that ensure GNSS time stamps are traceable to UTC from both a technical and a regulatory perspective [5]. This article describes how UTC is defined and realized and how a prediction of UTC is included in GNSS data transmissions.

The Definition and Realization of UTC 

The UTC time scale is a paper time scale that has no physical realization. It is computed monthly by the International Bureau of Weights and Measures (BIPM) based on data from several hundred atomic clocks located at National Metrology Institutes (NMIs) and other time centers in various countries. Many laboratories operate local ensembles of atomic clocks and use the data from these ensembles to compute and disseminate a local UTC estimate. This local estimate is identified as UTC(k), where k is the acronym for the laboratory. The estimate of UTC computed by the U.S. Naval Observatory (USNO) is UTC(USNO) and the estimate computed by the National Institute of Standards and Technology (NIST) is UTC(NIST). 

The computation of UTC for any month is published in BIPM Circular T by the tenth day of the following month [6]. This circular tabulates UTC-UTC(k) every five days for every participating laboratory. A rapid version of UTC, called UTCr [7], is also published by the BIPM every Wednesday. It lists daily values of UTCr-UTC(lab) through the previous Sunday. These data are published on the BIPM website and are distributed by email (Figures 1 and 2). 

GNSS Time Signals

The system time of a GNSS constellation, GNSS_T, is generated by the ground segment from an ensemble of clocks located on the ground at the control center and tracking stations. It also can include the clocks in the satellites [8-11]. Each satellite in a constellation transmits a prediction of the offset between the time of the clock on the satellite and the system time of the constellation, which is uploaded to the satellites periodically. GNSS constellations also broadcast bUTC_GNSS, a prediction of the difference between GNSS_T and UTC (including a 3-hour offset for the GLONASS system) that is derived from the UTC prediction of timing laboratories. This prediction is transmitted in two parameters: an integer giving number of whole seconds difference between UTC and the GNSS system time, and a fractional part, which specifies the difference modulo 1 s. The first parameter changes only when a leap second is inserted into UTC and not at other times. (The GLONASS constellation uses UTC as the system time so only the fraction is transmitted in the navigation message.)

For the GPS constellation, this prediction is derived from UTC(USNO) maintained at the U.S. Naval Observatory. The GLONASS constellation broadcasts a prediction based on UTC(SU), which is realized at the Russian Metrology Institute of Technical Physics and Radio Engineering (FSUE, VNIFTRI). The Galileo constellation uses a prediction derived from a collaboration of five European National Metrology Institutes. The BeiDou system uses UTC(NTSC) realized at the National Time Service center of China and UTC(NIM) realized at the China National Institute of Metrology. Regional systems also broadcast similar messages. The formats of the respective messages are GNSS-specific and are documented in the respective Interface Control Documents.

The Role of the BIPM

In addition to computing UTC and publishing the differences of UTC-UTC(k), the BIPM evaluates the difference between UTC and the predictions of UTC broadcast by the various GNSS constellations, bUTC_GNSS. These differences are published in Section 4 of BIPM circular T [6]. This section lists the difference in ns between UTC computed by the BIPM and the prediction of UTC transmitted by the GPS, GLONASS, Galileo and BeiDou satellites for every day in the monthly reporting period for that issue of Circular T. Table 1 shows the values from the August 2025 editor of Circular T interpolated from the five-day reporting interval in Circular T to a daily value at 0 UTC [12]. 

Linking User Equipment to UTC

There are two common configurations that support a link between the user’s time reference and UTC(k) or UTC. In the first configuration, the user has a clock (or an ensemble of clocks) that provides the reference signal for a GNSS timing receiver. The receiver does not discipline the free-running local clock (or ensemble) in the short term, but measures its time with respect to the signal broadcast by the satellites of some constellation. These data are combined with the data in the navigation message to (1) correct for the transit time between the satellite and the receiver, (2) include the offset between the satellite clock and the GNSS system time, and (3) add the prediction of the offset between the system time and UTC. 

Most receivers can be configured to implement these calculations in firmware, and the output data gives the difference between the local reference and the broadcast prediction of UTC. The signal from this clock (or clock ensemble) can be used in the user’s application or the application’s clock can be compared to it. The system connected to the GNSS receiver may be completely free-running and not disciplined by the GNSS data; its offset is recorded and used to adjust the downstream data. In some configurations, the time or frequency of the local reference clock is adjusted from time to time so the measured time difference is kept within some administratively defined tolerance. The interval between adjustments depends on this tolerance and on the frequency stability of the local reference, and it can range from minutes for a rubidium-based reference to hours or days for a cesium-based device. 

The second configuration, which is much more common, combines a GNSS receiver and an oscillator in a single device. There are many commercial systems that realize this configuration and often provide several outputs (5 MHz, 10 MHz and 1 pps) that are disciplined by the data received from the GNSS constellation. The simpler systems use the code data transmitted on the L1 frequency, but dual-frequency receivers and more sophisticated carrier-phase analyses are possible. The first GNSS disciplined oscillators usually used signals from the GPS constellation, but newer systems can track satellites from more than one constellation simultaneously. The output signal might be based on only the satellites from one constellation at any time or on a combination of the data received from multiple constellations. Either solution can produce significant steps in the output signals, especially in the PPS data, when the reference constellation changes. The details of the disciplining algorithm are often proprietary; the output could be disciplined to GNSS system time or to the prediction of UTC, and traceability to UTC would require the additional adjustment that incorporated the data published in BIPM Circular T. This additional adjustment, based on data from Circular T, may be small enough to ignore in some applications. 

The first configuration is more flexible; the measurement process can accept data from multiple sources, including common-view data, and implement more sophisticated post-processing methods. The adjustment process for the local reference clock can be adjusted to meet the requirements of the user’s application. The second configuration, on the other hand, may provide adequate performance in many applications. It is much simpler to operate, and this simplicity may be the deciding factor for many users.

Combining Data from Multiple Constellations

Combining GNSS signals from multiple constellations can significantly improve the timing performance of a user’s receiver, especially in locations with limited visibility of the sky. This approach requires a knowledge of the offsets between different GNSS time scales, which are at the level of a few ns and vary in time. It is possible for a user to solve for the inter-system bias between constellations [13] if enough satellites from both constellations are visible at the same time, but this is not always the case, and the broadcast values must be used [14]. The broadcast of the predicted time difference between each GNSS system time and UTC greatly simplifies the job of combining signals from multiple constellations when only broadcast data are available. The use of UTC as the common reference time scale eliminates the need for maintaining multiple inter-system bias values.

Metrological Traceability

The International Vocabulary of Metrology (VIM) defines traceability as the “property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty” [15]. The International Telecommunications Union (ITU) [16] and the International Laboratory Accreditation Conference adopted the same definition and refer to the International Organization for Standardization (ISO/IEC) standard 17025 [17].

The signals transmitted by the GNSS constellations can be traceable to UTC. The broadcast signals are linked to UTC through the UTC(k) data of a timing laboratory, and the transmissions are monitored by the BIPM with results published in Circular T. A user can also establish a common-view relationship with a timing laboratory, which can provide a near-real-time estimate of the offset of the user’s timing system with respect to the UTC(k) of that laboratory. In either case, these data are processed by the receiving system at the user’s site, and the calibration and statistical characteristics of this system directly affect the accuracy and stability of the timing data that control the user’s application. 

Timing Receiver Calibration

The calibration of the user’s equipment that is required to complete the demonstration of traceability should be performed by a method validated by a National Metrology Institute or a Designated Institute that participates in the Mutual Recognition Agreements (MRA) and have their Calibration and Measurement Capabilities (CMC) published in the Key Comparison Database maintained by the BIPM [18]. The Key Comparison Database maintains the equivalency between different organizations and guarantees the international acceptance of calibrations performed by different agencies that participate in the MRA.

The manufacturer’s published specifications can be the basis for specifying the performance of a stand-alone GNSS receiver or a GNSS receiver and disciplined oscillator combination. These specifications should be based on a calibration of one example of a particular model with some allowance for the variation among devices of the same type. For applications that require only modest accuracy (not greater than about 1 µs) a statement by the manufacturer that the device has been type-approved to that level is sufficient. The transmission delay even through a very long antenna cable is unlikely to invalidate this assumption.

The use of “type approval” may not be adequate for applications that require sub-microsecond accuracy. One method of calibrating a receiving system is to compare the output of the system to a source of UTC(k) by using a time-interval counter to monitor the difference. This method depends on an independent source of UTC(k), which might be provided by a traveling calibrated receiver, by transporting a running clock from the UTC(k) source to the location of the receiver, or by operating the device to be calibrated at a laboratory where a source of UTC(k) is available. 

Using a traveling receiver is the best choice because it tests the receiving hardware with the antenna and cables in the environment where it will be used. The BIPM uses this option to calibrate the time-transfer equipment at timing laboratories. Although the traveling receiver is calibrated, it is operated at a location where its position may not be known accurately, and where it may be influenced by multipath effects that are not the same as the effects on the device under test. These considerations are usually not important unless the required accuracy must be better than about 50 ns.

A calibration based on carrying a running clock from the source of UTC(k) to the location of the user’s equipment is feasible if the distance is not too great and the required calibration accuracy is not too high. For example, the GPS receivers at the NIST radio station in Fort Collins, Colorado, are calibrated by carrying a rubidium oscillator from the source of UTC(NIST) in Boulder to Fort Collins, a distance of about 100 km by road. The calibration is repeated by carrying a calibrated GPS receiver between the two locations. The accuracy of either method is estimated to be about 15 ns, and the two methods agree within this uncertainty.

Transporting the device under test to a location where an independent source of UTC(k) is available is usually the most difficult solution. It may be impractical to disconnect the antenna cable at the site, so a different cable must be used for the calibration. The delay through the actual cable can be estimated with a time domain reflectometer, but this method tests the cable with signals that are not the same as signals from real satellites. The impedances at the end-points are also different. 

If the system to be calibrated provides the contribution of each satellite in view to the composite output, then the common-view method can be used to calibrate the receiver. (Unfortunately, many disciplined oscillators do not provide these data.) The system to be calibrated measures the difference between the local clock (or clock ensemble) and the system time of the constellation by using the data from each satellite in view. These data are compared, satellite by satellite, with the same measurements made at a location where UTC(k) is available. The common-view difference cancels or attenuates the contributions of the satellite clock and the orbital parameters, which are common to both data sets and cancel in the differences in first order. If the distance between the locations of the user and the UTC(k) laboratory is not too great, the contribution of the ionosphere may also be common to both measurements and cancel in the difference. A multiple-frequency measurement, which can correct for the contribution of the ionosphere, may not offer a significant improvement over a simple L1 comparison in this configuration, because the contribution of the ionosphere will be cancelled or attenuated in the common-view subtraction. The common-view method can operate continuously, and can also monitor the stability of the remote system.

Frequency Calibration

The techniques described for timing calibration can also calibrate the output frequency of the user’s system. A frequency calibration can be easier to realize than a time calibration because the absolute values of the delays in the equipment are not important, only the stability of these delays is. The stability of the output frequency of a quartz oscillator may be degraded by fluctuations in the ambient temperature, and the frequency estimated with a reference based on a rubidium or cesium device may be degraded by changes in the multipath contribution.

Specific Recommendations

The documentation from the manufacturer is the best source of information about a particular device. The following specifications provide general guidance on the methods to establish traceability [19].

1. If the application can accept a fractional frequency uncertainty of 10^-8 or greater with an averaging time of one day, or a time uncertainty of 1 µs or greater, then a certificate by the manufacturer that at least one unit of the model satisfies the requirement is adequate to establish traceability at this level. (A receiver used only as the reference for a server that supports NTP, the Network Time Protocol, may not require calibration, because the accuracy and stability of the NTP service is usually limited to not better than about 1 ms by the characteristics of the network connection between the server and the client systems.) 

2. If the application requires a fractional frequency uncertainty between 10^-8 and 10^-10 with an averaging time of one day or a time uncertainty between 100 ns and 1 µs, then the manufacturer should provide a certificate with every unit that satisfies the requirement. The manufacturer could validate the performance of each unit by comparing its output with a calibrated reference unit maintained at the manufacturer’s facility. 

3. If the application requires a fractional frequency uncertain of less than 10^-10 with an averaging time of one day or a time uncertainty of less than 100 ns, then the calibration can be challenging and should be performed at the user’s facility, if possible. 

4. If the application requires a fractional frequency stability of less than 10^-12 or a time uncertainty of less than 50 ns, then the calibration should be repeated periodically or the performance of the system should be monitored by common-view or an equivalent technique, which will require a dedicated GNSS timing receiver at the user’s site. The contributions of multipath reflections and the sensitivity of the equipment to fluctuations in the ambient temperature may be important. The impact of multipath reflections can be minimized by locating the antenna so it has an unobstructed view of the sky, and by using a directional “choke ring” antenna, which attenuates signals coming from low elevations. The sensitivity to fluctuations in the ambient temperature may be a problem if the local reference device is a simple quartz oscillator or if a long antenna cable is exposed to direct sunlight. 

It is important to maintain documentation that validates the traceability of any system. Configurations that support this capability are particularly useful.

Summary and Conclusion

Applications that use the timing data from GNSS systems often require legal and technical traceability to UTC. Even when traceability is not legally required, maintaining traceability to UTC simplifies combining the data from multiple constellations. The signals transmitted by GNSS systems are monitored by the BIPM and can be made traceable to UTC by the methods discussed. Ensuring the traceability of the timing data in a user application also depends on a calibration of the receiving equipment. The methods for realizing this calibration were presented and specific recommendations provided. Maintaining adequate documentation is important, and configurations that support real-time monitoring and log files are particularly useful. 

References 

(1) Conference generale des poids et mesures (CGPM) 2018 Resolution 2 of the 26th CGPM (2018), on the definition of time scales (https://bipm.org/en/committees/cg/cgpm/26-2018)

(2) MiFiR RTS 25: https://ec.europa.eu/finance/securities/docs/isd/mifid/rts/160607-rts-25_en.pdf

(3) Finra Rule 6820: https://www.finra.org/rules-guidance/rulebooks/finra-rules/6820

(4) IEEE Standard for Synchrophasor Measurement for Power Systems, IEEE C37.118.1-2011. https://standards.ieee.org/ieee/C37.118.1/4902.

(5) Dimetrios Matsakis, Judah Levine, and Michael Lombardi, Metrological and Legal Traceability of Time Signals, Inside GNSS, March/April 2019, pp. 48-58.

(6) https://www.bipm.org/en/time-ftp/circular-t

(7) https://www.bipm.org/en/time-ftp/utcr

(8) GPS system time: https://www.gps.gov/applications/timing

(9) Galileo system time: https://www.gsc-europa.eu/GST

(10) GLONASS system time: https://www.unoosa.org/documents/pdf/icg/2020/GLONASS_Time_2017_E.pdf

(11) BeiDou system time: http://en.beidou.gov.cn/SYSTEMS/Officialdocument/202001/P020231201549662978039.pdf

(12) https://webtai.bipm.org/ftp/pub/tai/other-products/notes/explanatory_supplement_v0.8.pdf

(13) G. Huang, Q. Zhang, W. Fu and G. Guo, GPS/GLONASS time offset monitoring based on combined precise point positioning approach, Advances in Space Research, Vol. 55, number 12, 15 June 2015, pp. 2950-2960. DOI: https://doi.org/10.1016/j.asr.2015.03.003. See also references in that text.

(14) GPS-Galileo Time Offset (GGTO): https://www.unoosa.org/documents/pdf/icg/2017/wgd/wgd4-2-2.pdf

(15) https://www.bipm.org/documents/20126/54295284/VIM4_CD_210111c.pdf

(16) ITU-R, TF-686-3, Glossary and Definitions of Time and Frequency Terms p 16. https://www.itu.int/dms_pubrec/itu-r/rec/tf/r-rec-tf.686-3-201312-i!!pdf-e.pdf

(17) SO 17025:2017, General requirements for the competence of testing and calibration laboratories, https://www.iso.org/ISO-IEC-17025-testing-and-calibration-laboratories.html

(18) https://www.bipm.org/en/cipm-mra

(19) P. Defraigne, J. Achkar, M. J. Coleman, M. Gertsvolv, R. Ichikawa, J. Levine, P. Uhrich, P. Whibberley, M. Wouters and A. Bauch, Achieving traceability to UTC through GNSS measurements, Metrologia, vol. 59, Number 6, October 2022. Metrologia, 59, 064001. DOI: 10.1088/1681-7575/ac98cb.

Authors

Judah Levine is on the faculty of the Department of Physics at the University of Colorado at Boulder. He recently retired from the Time and Frequency Division of NIST, where he worked on time scales and methods of distributing time and frequency information. He is continuing those projects at the University and is also a member of committees of the International Bureau 
of Weights studying the future of Coordinated Universal Time and possible time scales for the Moon.

Pascale Defraigne obtained her Ph.D. in Geophysics in 1995 at the Université Catholique de Louvain. Since 1997, she has managed the time and frequency activities at the Royal Observatory of Belgium, where the Belgian reference UTC (ORB) is maintained. Her research activities mainly concern the use of satellite navigation systems for time and frequency transfer. Pascale presently chairs the CCTF working group on GNSS time transfer, and contributes to the validation of Galileo timing signals.

Ilaria Sesia is a Senior Researcher and Head of the Time and Frequency Department at INRiM, where she works on time transfer, atomic clocks and time scales for satellite applications. Since 2004, she has been deeply involved in the design and development of the timing aspects of the Galileo System.

Giulio Tagliaferro received his Ph.D. in 2021 from Politecnico di Milano on precise GNSS measurement adjustment. He is currently a physicist at BIPM, where he works on GNSS time-transfer activities and receiver calibration supporting the realization of UTC.

Michael Wouters leads the time and frequency group at the National Measurement Institute in Sydney, Australia. His research focuses on using low-cost GNSS receivers for time-transfer. He chairs the Consultative Committee on Time and Frequency’s task group working on the traceability of GNSS timing signals to UTC.

The post Linking GNSS Data to UTC appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.