Retrofitting At-risk GPS/GNSS Critical Infrastructure with Resilient and Cost-effective PNT Systems

GPS and other Global Navigation Satellite System (GNSS) satellite signals are the backbone of modern navigation, positioning, and timing systems. From battlefield coordination to the synchronization of financial transactions, these signals ensure seamless operations. But what happens when GPS signals are jammed or spoofed?

Unfortunately, this isn’t a hypothetical situation anymore. The frequency and sophistication of jamming and spoofing attacks are escalating, leaving organizations, personnel and infrastructure vulnerable. For aviation or rail that rely on GPS for synchronization, losing this trusted time source could create catastrophic outcomes. On the battlefield, where every microsecond matters, the inability to access reliable positioning, navigation, and timing (PNT) data can mean the difference between mission success and failure.

This isn’t just a transport or battlefield issue and has ramifications into many industry verticals.

The ripple effect of such disruptions extends to critical infrastructures like 5G networks, power grids, ATMs, and financial networks. Without a trusted time source, industries that power our societies crumble. The question is—how can we prevent it?

The Need for Resilient Positioning, Navigation, and Timing Systems

The solution lies in creating systems that can withstand and adapt to disruptions. Resilient PNT technology oKers an answer by pulling timing data from multiple sources. Instead of being fully reliant on a single vulnerable GNSS source, these systems utilise alternative constellations, such as Low Earth Orbit (LEO) or Geostationary (GEO) satellites. They can even incorporate signals that leverage authentication protocols to ensure that what’s being received is real and untampered.

Replacing existing hardware with newer GNSS systems, however, comes with significant challenges, especially in active military zones or on equipment that is in permanent usage. Retrofitting large fleets of vehicles and equipment can be prohibitively expensive and logistically unfeasible. Equipment often needs to be sent back to manufacturers, resulting in downtime—a luxury often unavailable without causing massive disruption.

There have been some major innovations recently involving retrofitting solutions. Imagine a compact AI-controlled black box that integrates advanced multilayer technology to deliver resilient timing, without requiring extensive retrofitting or the need for equipment to be returned to manufacturers. VIAVI has created a solution, which has been battlefield-tested in real-world scenarios where GPS and GNSS signals were intentionally rendered unavailable. The results? Seamless functionality and an assured PNT state, ensuring uninterrupted operations in critical moments.

The SecurePNT 6200 is an inline hardware device that sits between the existing GPS/GNSS antenna and receiver system. It integrates state-of-the-art technologies to fuse multiple data sources and output a highly precise, resilient, and assured L1 GPS signal that legacy equipment can recognize.

Here’s how it achieves this revolutionary transformation:

• Multilayer Source Switching - The system taps into alternative GNSS constellations using a range of frequencies, including LEO and GEO, to dodge the disrupted spectrum. By integrating these sources with redundancy in mind, the black box ensures uninterrupted operation even during active interference.
• Authentication for Spoofing Prevention - SecureTime℠ Services feature Navigation Message Authentication (NMA) technology, which detects and prevents spoofing attempts using encryption protocols.
• Ultra-Precise Internal Clocking - Advanced DOCXO or Rb oscillators deliver timing that is accurate to within nanoseconds of Coordinated Universal Time (UTC), critical for high-stakes applications.
• AI-driven Fusion - By leveraging machine learning, deep learning, and neural networking models, the SecurePNT 6200 evaluates and ranks the quality of available sources. It outputs an optimal estimation of the current PNT state for uninterrupted operation.

Additional Benefits

This solution eliminates some of the greatest barriers to upgrading critical equipment.

1. Field-friendly Installation: SecurePNT 6200 ensures that retrofitting can be performed in the field, removing the need for costly and logistically complex manufacturer returns.
2. Real-world Resilience: Unlike traditional systems that crumble under jamming/spoofing, this black box enables seamless continuity of service.
3. Cost-effectiveness: By enabling the extension of the lifespan of existing equipment, this solution significantly reduces operational overhead. Organisations can quickly modernize their fleets without overhauling their infrastructure entirely.

Applications Across Industry Verticals

What makes VIAVI’s solution extraordinary is its versatility across industries and infrastructures. While combat scenarios demand resilient PNT systems for survival and mission-critical functionalities, other sectors also benefit from reliability. For instance:

• Telecommunications: 5G networks rely on precise synchronization of transmitted signals to reduce interference, achievable through SecureTime℠ Services that prevent interruptions caused by GNSS vulnerabilities
• Energy and Utilities: Critical infrastructures like smart grids depend on precise synchronisation for AC phase alignment and cannot tolerate timing disruptions
• Financial Services: Financial trading systems and stock exchanges require nanosecond-accurate timing to audit sequences of trades and to ensure that trades are executed at the optimal moment
• Transportation: Accurate timing coordination between distributed sensors of transportation safety systems maximises transportation capacity while delivering the highest safety standards
• Datacentres: Precision time synchronisation is essential to ensure global data integrity, audit operations and ensure that complex compute systems can synchronise their interactions for maximal eKiciency and performance
• Defence: All aspects of the military require resilient timing, from synchronising battlefield radios, precise location to avoid artillery or the accurate navigation of aircraft and vehicles that rely on GPS signals

By leveraging VIAVI’s comprehensive solution, these industries can secure their operational continuity and eliminate risk with a simple, in the field retrofit.

Already Proven in the Field - The SecurePNT™ 6200 has already demonstrated its eKicacy in live-sky battlefield scenarios. Whether in war zones or urban environments with high signal interference, this revolutionary technology has consistently delivered trusted timing.

How to Secure Assured PNT for Your Organization

The need for resilient PNT systems has never been clearer. Whether you’re safeguarding military operations or protecting critical civilian infrastructure, ensuring uninterrupted timing relies on secure, forward-thinking solutions like VIAVI’s SecurePNT 6200.

Learn more about how you can deploy the SecurePNT 6200 by visiting VIAVI’s website or contact a VIAVI Solutions expert for a tailored consultation.

The future of positioning, navigation, and timing is here—and it’s resilient, costeKective, and ready to protect what matters most. Trustable Timing is Everything.

Chris Murphy, the author, will be speaking in the Digital Twins session, sponsored by VIAVI, at CWIC 2025 and joining the PNT panel. Book your tickets here.