From jamming and spoofing to degraded signals in dense environments, these threats are real—and they require resilient, scalable and intelligent solutions.

That’s where etherwhere comes in. Marrying controlled reception pattern antenna (CRPA) chip-level innovations with a cloud-based infrastructure built for high-volume deployments, Etherwhere is solving mission-critical PNT challenges at scale. Whether it’s tracking cattle in the Amazon, monitoring global pallet networks, automating retail logistics, or building sovereign timing systems, the company is helping reshape how organizations think about GNSS reliability and flexibility.

EMBEDDED RESILIENCE THROUGH CRPA

At the heart of etherWhere’s approach is a CRPA architecture integrated directly at the board level—enhancing the ability to mitigate jamming and spoofing without requiring external modules or signal chains.

“The value of board-level CRPA is that it delivers resilience as a default—baked into the system design rather than layered on top,” said Michael Raam, CEO of etherWhere.

This decision is as strategic as it is technical. By aligning with Export Administration Regulations (EAR) rather than International Traffic in Arms Regulations (ITAR), 
etherWhere’s solutions are accessible to both domestic and international partners. And with growing demand from civil, defense and commercial sectors for multi-layered PNT protection, board-level CRPA gives developers a head start in achieving compliance and reliability.

CLOUD-BACKED CUSTOMIZATION

etherWhere isn’t just a chip company—it’s a vertically integrated platform provider. The same chip that receives satellite signals also syncs with a cloud backend that handles configuration, optimization and application logic. The result: end-to-end systems that are customizable per use case, yet scalable by the millions.

One example: a large-scale cattle tracking solution in South America, designed to meet stringent European Union deforestation compliance regulations. The tags operate in harsh, signal-limited environments—under trees, across miles of terrain, and without guaranteed human interaction.

“We built cloud-managed modes of operation that adapt signal acquisition strategies based on terrain, movement and activity patterns,” Raam said. “The tag knows how to behave based on its context.”

Other clients use etherWhere’s solution to track pallets globally, register retail appliances automatically, or deliver redundant timing services combining GPS and Iridium. While the domains differ, the core system—chip, firmware and cloud—remains modular and tunable.

“We’re focused on use cases where the volume justifies customization. That means chip, tag and cloud all working together for the mission.”

VOLUME-FIRST STRATEGY

Unlike traditional solution providers who optimize for niche integrations or bespoke systems, etherWhere’s sweet spot lies in high-volume environments—specifically those with at least a million units per year or those that can justify disposable infrastructure.

In one application, a leading electronics company uses etherWhere’s tag to automate warranty and ownership registration for appliances. In another, their chips track automobiles from manufacturer to dealership, eliminating costly misplacements and improving delivery visibility.

The approach enables etherWhere to support custom solutions through non-recurring engineering (NRE) fees, while generating revenue through chip sales and cloud subscriptions.

“Customization slows time to market—but at scale, it becomes a competitive advantage.”

BROAD MARKET RELEVANCE

While the cattle tracking use case may serve as an accessible entry point, it’s far from unique. etherWhere’s chips are also being tested in tracking radioactive medical materials, where chain-of-custody and compliance are paramount. In another vertical, their precise timing solutions are enabling more resilient communications infrastructure by combining GPS with alternate constellations for redundancy.

Raam also teased the company’s next-generation solution: a “tag in a chip” architecture that integrates low-power multi-band GNSS, software-defined radio and cloud-native orchestration—all in a single package. This evolution represents etherWhere’s push toward miniaturization and autonomy without sacrificing reliability or flexibility.

BUILDING A TIME-SOVEREIGN FUTURE

As discussions about sovereign timing grow louder in the halls of government and telecom operators, etherWhere’s blend of low-jitter timing, multi-signal redundancy, and cloud-backed configuration is gaining traction.

“Resilient time is just as important as resilient position,” Raam said. “And we’re helping customers build that foundation without needing GPS to be infallible.”

This message aligns with global PNT policy discussions—particularly in Five Eyes and NATO nations—about the need for more robust alternatives to GNSS, especially in contested or denied environments.

WHAT COMES NEXT

With a planned controlled reception pattern antenna (CRPA) strategy at the board level and cloud-enabled customization across millions of devices, etherWhere is redefining what GNSS resiliency means for real-world autonomy and asset tracking—from agriculture and infrastructure to logistics and timing.

With the Joint Navigation Conference (JNC) approaching, etherWhere plans to expand its message to a broader cross-section of stakeholders—from defense program leads and commercial integrators to satellite infrastructure providers and timing authorities.

As Raam puts it: “Whether you’re tracking a cow, a crate or a critical signal, you need systems that deliver certainty—not just accuracy. That’s what we’re building.” 

The post Resilience at Scale: etherWhere’s Chip-Cloud Ecosystem Tackles GNSS Vulnerability in High-Volume Applications appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

As threats to GNSS signals—ranging from unintentional interference to deliberate jamming—continue to grow, building resilience into the system is no longer optional. While software-based defenses and downstream technologies get much of the attention, the first line of defense is often overlooked: the GNSS antenna.

THE ANTENNA: THE UNSUNG HERO OF GNSS RESILIENCE

GNSS antennas are the gateway to space-based navigation data. Every signal that fuels precision positioning, navigation and timing (PNT) solutions starts its journey through an antenna. As such, the antenna’s design, performance and configuration play a pivotal role in ensuring the integrity, continuity and availability of GNSS services.

Modern threats to GNSS aren’t just about accidental interference—they’re also about intentional jamming. Jamming devices can easily block GNSS signals that are already weak when they reach Earth. In these hostile environments, a robust antenna is the first—and often the most effective—layer of defense.

ENVIRONMENTAL AND MECHANICAL RESILIENCE

A resilient GNSS system also requires antennas that can withstand harsh 
environments—extreme temperatures, physical shock, vibrations and electromagnetic threats. Ruggedized enclosures, weatherproofing and electromagnetic shielding ensure continuous operation in field conditions, whether on a remote oil rig, a military convoy or a satellite uplink station.

FILTERING OUT THE NOISE: INTERFERENCE REJECTION AT THE FRONT END

Advanced GNSS antennas are equipped with high-quality filters that reject out-of-band interference before it reaches the antenna low noise amplifier (LNA) and GNSS receiver. With the proliferation of adjacent-band systems like 5G, interference at the antenna level is becoming more frequent. A high-performance antenna can significantly improve system resilience by ensuring only the desired GNSS frequencies are processed, reducing the noise floor and increasing the signal-to-noise ratio (SNR).

Calian’s XF+ technology provide 80 dB of out-of-band mitigation (from 400-2500 MHz). The + feature splits the signal amplification paths into two independent frequency channels (upper [L1] and lower [L2] bands). The result is that XF+ will enable the antenna to continue to provide the attached receiver with a usable signal if either L1 band or L2 is jammed but not both.

MULTI-BAND, MULTI-FREQUENCY CAPABILITY: DIVERSITY AS A DEFENSE

Resilient GNSS systems increasingly rely on multi-frequency and multi-constellation capabilities. Antennas that support GPS, Galileo, BeiDou and regional systems across multiple frequencies (L1, L2, L5, etc.) ensure receivers have more signals to estimate PNT. 

A jamming attack may target the GPS/Galileo L1/E1 signals, but if the antenna is also receiving GPS L2 and Galileo E5b signals, the XF+ antenna will provide a usable signal to the receiver. Thus, an XF+ enabled multi-band GNSS antenna is an integral component in a resilient GNSS system.

LOW ELEVATION ANGLE NULLING ANTENNA

Low elevation angle nulling antennas (LEANA) offer significant benefits where interference and jamming signals are transmitted from the ground up to an elevation angle of approximately 15 degrees. By suppressing or “nulling” signals coming from low elevation angles, LEANA antennas attenuate the jamming signal by approximately 15 to 20 dB and prevent the antenna’s LNA from saturating. As a result, systems using LEANA antennas can continue to function when the jammer is 10 times closer to the LEANA than a standard GNSS antenna. (See Calian TW3742AJ and AJ977XF+ LEANA products.)

DIRECTIONAL BEAMFORMING AND NULL STEERING

State-of-the-art GNSS antennas now include controlled reception pattern antennas (CRPAs), which use beamforming techniques to suppress interference from jamming sources. By electronically steering nulls toward interference sources, CRPAs provide a powerful mechanism for real-time resilience and situational awareness in areas with active jamming or interference.

This technology, once reserved for military applications, is now available for commercial and critical infrastructure use. Paired with sophisticated GNSS receivers, CRPA antennas give operators an agile, intelligent front-end defense against in-band interference and jamming signals. Calian’s CR8894SXF+ family of products are designed to mitigate three jamming signals in both the upper and lower band for a total of six. Calian’s CRPA technology provides mitigation ranging from 20 dB (wide band chirp jammer and enables PNT estimation up to 10 times closer to the jammer) to 40 dB (continuous wave jammer and enables PNT estimation up to 100 times closer to the jammer).

INVESTING IN THE RIGHT RESILIENT GNSS ANTENNA PAYS DIVIDENDS

Choosing a high-quality GNSS antenna is not a minor detail—it’s a strategic decision that can make or break a mission-critical system. For operators designing resilient PNT solutions, investing in the right antenna isn’t just smart—it’s essential. Contact Calian GNSS for more information at in*******@****an.com.

The post Strengthening GNSS Resilience at the Source: The Critical Role of GNSS Antennas appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

Founded by Jeff Sanders, a well-known SME in the SIGINT community, UHU Technologies brings decades of expertise to one of today’s most pressing challenges: assuring trusted positioning navigation and timing (PNT) and providing unmatched PNT Situational Awareness (PNT SA) in contested environments.

Inside GNSS sat down with Sanders to discuss UHU’s two flagship products—the UHU 1000 and the Northstar—and the company’s mission to enhance real-time awareness, threat detection, and operational confidence for all GPS-enabled operations.

THE UHU 1000: DEFINING NEW STANDARDS IN PNT SITUATIONAL AWARENESS

At the core of UHU Technologies’ offering is the UHU 1000, a 7-channel system specifically designed to combat advanced GPS attacks while simultaneously locating their source. “Our goal with the UHU 1000,” Sanders explained, “was to create a system that delivers comprehensive PNT situational awareness—not just defending against attacks but enabling users to understand, visualize and respond to them in real time.” 

Key features of the UHU 1000 include:

• Impervious to Spoofing: Spatial validation confirms the authenticity of each satellite by validating angle-of-arrival.

• Adaptive Nulling Anti-Jam: Real-time elimination of interfering signals, preserving operational continuity.

• Non-Adaptive Nulling Anti-Spoof: Separates spoofed signals for continuous situational clarity.

• Integrated Timing Receiver: Maintains precise timing even under GPS denial conditions.

• I/Q Recording: Captures detailed signal environments for forensic PNT analysis.

• Situational Awareness GUI: Multiple operational views—Sky, Map, Chart and Spectral—offering full visualization of the GNSS environment.

Housed in a compact 1U 19-inch rackmount chassis, the UHU 1000 empowers users to maintain trusted PNT while achieving continuous, actionable awareness of the threat landscape.

“We designed it to ensure that operators always know not just that there’s a problem, but exactly where it is and how it’s affecting their mission,” Sanders said.

THE NORTHSTAR: EXPANDING PNT SA TO CRITICAL INFRASTRUCTURE

While the UHU 1000 is geared for military and high-security governmental operations, the Northstar system brings robust PNT Situational Awareness to civil infrastructure—a rapidly growing vulnerability as ports, airports and financial systems depend more heavily on GPS.

“Northstar was built to give operators the ability to see—in real time—what’s happening in their GPS environment, with the power to react immediately,” Sanders said.

Highlights of the Northstar system include:

• 4-Channel Antenna System: Differentiates authentic GNSS signals from threats via spatial processing.

• Rapid Threat Detection: Provides immediate alerts and visualizations when spoofing or jamming occurs.

• Automatic Timing Holdover: Maintains operational timing continuity during attacks.

• Angle-of-Arrival Threat Localization: Displays the direction and magnitude of threats to enhance operational decision-making.

• Remote RF Disconnect: Automatically protects external GPS receivers by isolating corrupted signals.

• Event-Based I/Q Recorder: Enables in-depth analysis for sustained PNT SA improvements.

With a user interface designed around Sky View, Map View and Time Machine replays, Northstar transforms GPS-dependent facilities into PNT-aware operations hubs.

“Northstar isn’t just monitoring the sky,” Sanders emphasized. “It’s giving operators a window into the PNT battlespace.”

REAL-WORLD IMPACT: ENHANCING PNT SA AT PORTS, BORDERS AND AIRPORTS

Sanders recounted real-world deployments where enhanced PNT situational awareness made a critical difference. At a major U.S. port, a rogue refrigeration unit was emitting interference, crippling GPS container tracking. A UHU rapid deployment kit quickly located and isolated the source, restoring operational stability.

“PNT SA is about understanding disruptions before they become operational crises,” Sanders explained.

“Knowing when, where and how GPS is being attacked along a sensitive border isn’t just a bonus—it’s critical for mission success and international safety,” Sanders said.

RAPID DEPLOYMENT: DELIVERING IMMEDIATE PNT AWARENESS

Both the UHU 1000 and Northstar were designed from the ground up to provide rapid, on-the-move situational awareness:

• Installation: Fully operational within one hour.

• Mobility: Easily mounted on vehicles using magnetic mounts and stowed in low-profile duffel bags.

• Real-Time Data Streaming: Secure transmission over VPN-enhanced cellular networks.

“Fast, reliable PNT SA shouldn’t require a full engineering team on site,” Sanders said. “Our systems bring clarity to the field immediately.”

A VISION FOR BROADER PNT RESILIENCE: AVIATION, ENERGY AND MARITIME

With civil aviation, maritime and power grid operators now confronting growing GPS vulnerabilities, UHU Technologies is expanding the reach of its PNT Situational Awareness solutions.

Sanders cited a recent incident at a major airport where GPS interference disrupted navigation, forcing pilots to revert to Instrument Landing Systems (ILS) and causing operational delays.

“Without real-time PNT SA, critical infrastructure becomes reactive rather than proactive,” Sanders said. “Our mission is to change that.”

Upcoming demonstrations, including at NAVFEST, will showcase how UHU’s systems can be networked across facilities for distributed, collaborative PNT threat detection.

INTEGRATING PNT SA INTO DOD PROGRAMS OF RECORD

As GPS jamming and spoofing incidents escalate worldwide, the future of military navigation will depend heavily on integrated PNT Situational Awareness. Key Department of Defense (DoD) Programs of Record, particularly in areas such as resilient communications, aviation command and control, autonomous systems, and expeditionary logistics, are increasingly recognizing the need to incorporate field-proven technologies like UHU’s. Real-time detection, localization and mitigation of PNT threats must become intrinsic to platform and mission system designs. 

By integrating UHU’s advanced capabilities, these programs can move from a model of after-the-fact vulnerability assessment to a proactive, resilient posture—ensuring continuous mission assurance even in PNT contested or denied environments.

PNT SA AS A CORE OPERATIONAL CAPABILITY

Reflecting on UHU Technologies’ strategy, Sanders summarized the new reality:

“You can’t defend GPS today without superior PNT Situational Awareness. It’s no longer about responding to disruption—it’s about knowing disruption is happening before it impacts your mission.”

With the UHU 1000 and Northstar, UHU Technologies is redefining the standard for resilient, real-time awareness—transforming PNT from a passive dependency into an active operational advantage.

As the global GNSS landscape grows more contested, UHU Technologies ensures operators across sectors will not only survive—but thrive—with trusted PNT.

The post Defending GPS Integrity: How UHU Technologies is Shaping the Future of PNT Situational Awareness appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

This white paper presents the Assured Position Navigation and Time (APNT) Problem Statement for UAVs and Loitering Munitions. It explains the different types of PNT and concludes that Precision Absolute PNT is essential to successful mission completion for UAVs and Loitering Munitions. This assessment measures mission success based on Cost Per Successful Mission (CPSM). 

We discuss the many environmental and adversarial threats that can impair the sensors needed to provide APNT, specifically threats to GPS/SATNAV and Vision Map Matching, and show how they impact performance. We discuss potential solutions to enable provision of APNT within the threat environments.

We propose an architectural approach that optimizes reuse and reduces cost by using a Common APNT Package (CAP) to maximize flexibility for a given platform and maximize scalability across platforms.

Finally, we show how Modernized GPS that is toughened and augmented enables successful mission completion in the face of significant GPS jamming and spoofing.

The modern battlespace has changed over the past decade, and the military use of GPS to deliver critical positioning, navigation and timing (PNT) information to warfighters faces challenges from adversaries’ threat systems. We have seen several examples of outdated GPS solutions failing to provide adequate (or in some cases any) PNT performance on the battlefield in Ukraine and elsewhere. Modernized (M-Code) GPS, however, continues to be relevant for the U.S. military and its allies, even when used in contested environments. Existing and future military GPS solutions must especially consider those uses designed for handheld and ultrasmall applications where size, weight, power, and cost (SWaP-C) are all key considerations.

APNT FOR UAVS AND LOITERING MUNITIONS 

Access to Precision Absolute PNT is critical to the successful execution of missions for UAVs and Loitering Munitions.

“Precision” PNT, as distinct from non-precision or relative PNT, is usually defined within the defense industry as error of less than 10 meters for positioning applications and less than 1 millisecond for communications applications. “Absolute” PNT is defined as using the World Geodetic Survey 1984 (WGS84) reference frame and Coordinated Universal Time (UTC) (Figure 1, Quadrant D).

The warfighter is dependent on Precision Absolute PNT to perform many of the missions anticipated by UAVs and Loitering Munitions in all weather, day/night and all terrains. Figure 2 shows why Precision Absolute PNT (Quadrant D) is important to UAV and Loitering Munition effectiveness. It provides full mission capability across all mission types while other levels of APNT performance (Quadrants A-C) 
provide partial mission capability for some missions and remain not mission capable for many mission types.

APNT THREAT ENVIRONMENT AND POTENTIAL SOLUTIONS

GPS and SATNAV Threats

GPS as well as other SATNAV sources are vulnerable to a variety of threats as shown in Figure 3. The threat environment ranges from “Permissive” in column 1 through “SATNAV Unavailable” in column 7. Columns 2 through 4 involve jamming and/or spoofing and are solvable using anti-jam and anti-spoof technology to toughen the GPS sensor along with inertial dead 
reckoning and clock coasting to augment the GPS sensor.

Column 5 represents a condition where GPS has been taken offline altogether and the solution involves switching to an alternative “Precision” SATNAV source, such as Galileo. By toughening and augmenting this alternative SATNAV source, a solution is provided for up to long temporary outages. Column 6 shows a condition where all “Precision” SATNAV sources have been taken offline and is solved by use of alternative SATNAV sources of lower precision, such as ALTNAV or other LEO-based PNT. Again, toughening and augmenting this alternative SATNAV source enables a solution through long, temporary outages of this source. Column 7 represents a condition where all SATNAV sources have been taken offline. In this condition, there is not a SATNAV-based APNT solution available.

Vision Map Matching Threats

Vision Map Matching is vulnerable to a different variety of threats as shown in Figure 4. The threat environment ranges from “Permissive” in column 1 through “Vision Unavailable” in column 6. 

Providing PNT using Vision Map Matching requires precise time initialization and clock coasting in all threat conditions. Columns 2 and 3 represent vision impairment in the visible spectrum and multiple spectrums, respectively. The solution involves adding multi-spectrum map matching capability. Columns 4 and 5 represent a combination of threats, including impairment, unrecognizable terrain and potentially dazzling, combining to cause short- or long-term Vision Map Matching outages. The solution involves adding inertial dead reckoning to the clock coasting and multi-spectrum sensing needed for Columns 1 through 3. Column 6 involves loss of Vision Map Matching capability due to burnout or other causes resulting in no vision-based APNT solution.

Merged SATNAV & Vision Map Matching Solution

The lack of correlation between the threats affecting GPS/SATNAV versus those affecting Vision Map Matching provides an opportunity for an enhanced APNT capability by merging the solutions. Figure 5 shows the enhanced ability to provide an APNT solution across all SATNAV and vision threat conditions. As can be seen, Precision Absolute PNT (Quadrant D in Figure 1) is provided across most threat conditions. A degraded, but still significant, PNT capability is provided for the rest of the combined threat conditions with the exception of both SATNAV and vision being unavailable simultaneously.

Vision Map Matching provides significant benefit to a GPS/SATNAV-only solution, as shown by the cells with bold lettering. Vision improves accuracy of the GPS/SATNAV solution when in a long outage and provides a PN (not T) solution when SATNAV is unavailable.

Likewise, it is interesting to observe the benefit gained by adding GPS/SATNAV to a Vision Map Matching solution. Figure 6 shows the same merged threat condition matrix with a Vision Map Matching only solution. Here, we see that without the precision time of GPS/SATNAV to at least initialize a clock coasting function for the vision system, PNT is degraded to just PN (no time). Likewise, without GPS to initialize platform location, vision-based PNT may struggle to operate or fail to operate altogether. Additionally, without GPS, PN performance will be degraded as outages extend to long time periods. So, all rows benefit from GPS/SATNAV precise position and time and the two lowest rows benefit by having access to a Precision Absolute PNT solution when vision outages become long or permanent.

PROPOSED UAV AND LOITERING MUNITIONS ARCHITECTURE

We propose optimization of the UAV and Loitering Munitions architecture to minimize CPSM across the missions of a given platform and across platforms. We recommend defining a minimum viable set of platforms to cover the mission types and determine breakpoints between platform types for:

• Expendable

• Attritable

• Survivable

Figure 7 shows our understanding of the current breakdown of UAV and Loitering Munitions platforms. The better we all understand the breakdown of planned platforms, the better we can optimize 
solutions to provide the best performance at the lowest cost.

ARCHITECTURE OF KEY UAV SYSTEMS

To optimize CPSM, we recommend incorporating a Common APNT Package (CAP) that is part of the UAV platform, not mission payload, but distinct from the navigation/guidance package. We recommend that all mission payloads that require PNT receive it from the Common APNT package.

For purposes of this discussion, we are defining platform to include all elements of the UAV that remain constant across all mission types. We are defining mission payload as those elements that may change based on the selected mission.

We recommend the CAP incorporate an APNT multi-sensor package that meets mission skyline requirements for a given platform, including:

• M-Code GPS

• Anti-jam

• Anti-spoof

• Assured sensor fusion

• Dead reckoning (including inertial, velocity, altitude, etc. sensors)

• Clock coasting

• Multi-SATNAV

• Vision Map Matching

We recommend implementing a common standard sensor interface to optimize modularity between sensors. We also recommend implementing a common standard PNT distribution interface for all mission packages to optimize use of the PNT data from CAP across the platform, including all mission packages requiring PNT.

Figure 8 shows the proposed top-level architecture including a CAP in the platform with a common standard PNT interface to enable use across all mission payloads.

Figure 9 shows a proposed CAP and mission payload architecture and how it optimizes reuse and flexibility across missions while reducing cost and maximizing scalability across platform types.

Figure 10 shows a general APNT architecture model that enables modularity, flexibility and scalability. It is tailored for the UAV and Loitering Munitions problem space, where the bolder colored items are included and the faded items are optional. Note the center of the model is assured sensor fusion, not a specific sensor. By putting sensor fusion in the middle, we optimize flexibility and scalability, and by making it assured, we optimize provision of assured PNT. The key to assured PNT is the Integrity Ring shown on the diagram, where the integrity of individual sensor outputs is validated prior to inclusion in the assured sensor fusion solution.

SYSTEM PERFORMANCE (JAMMING/SPOOFING) FOR UAVS AND LOITERING MUNITIONS

To illustrate performance of the proposed architecture in a GPS jamming environment, Figure 11 shows the relative performance of various GPS configurations, including current GPS as well as improvement using different generations of GPS M-Code, and M-Code with Regional Military Protection (RMP). As shown in Figure 11, current M-Code GPS receivers provide better anti-jam performance than the legacy military GPS receivers and much better than commercial GPS receivers currently used by many UAV platforms. This allows operation closer to the jammer while maintaining Quadrant D precision absolute position and time. 

For the small area of operation where GPS is potentially denied, non-GPS augmentation technology such as inertial dead reckoning or vision navigation can supplement the PNT solution to provide continuous assured PNT. In a corner condition where both GPS is denied and the non-GPS augmentation is unavailable, an outage of PNT is possible (Figure 5).

In addition to GPS jamming, GPS spoofing is an important consideration for operation in a threat environment. The most robust navigation systems include a layered approach to PNT integrity, using all available sensors and sophisticated algorithms to ensure a trusted solution. 

Current military GPS receivers include several anti-spoofing techniques and provide the foundation of a layered integrity approach. When an AJ antenna is applied, more sophisticated algorithms provide the highest level of PNT integrity available for a military GPS receiver. These algorithms do not depend on specific threat characteristics for detection, can mitigate mixed threat scenarios, and provide a trusted GPS cold start capability.

In addition to GPS technologies, non-GPS augmentation technologies can be used to enhance integrity by using consistency checks across multiple sensors. Together, this multi-layered approach provides a very robust anti-spoofing solution in all operational scenarios. 

CONCLUSIONS

APNT, especially Assured Precision Absolute PNT (Quadrant D in Figure 1), is essential to successful mission completion for UAVs and Loitering Munitions. This is made clear when assessing success based on CPSM. 

We have shown the many environmental and adversarial threats that can impair the sensors needed to provide APNT. We described those threats, specifically threats to GPS/SATNAV and Vision Map Matching, and have shown how they impact performance. We have further included potential solutions to enable provision of APNT within the threat environments. Of special note is the benefit of combining GPS/SATNAV with Vision Map Matching, which provides good APNT performance across all but the most extreme combined threat environment.

We have proposed an architectural approach that optimizes reuse and reduces cost by using a CAP that maximizes flexibility for a given platform and scalability across platforms.

Finally, we have shown how Modernized GPS that is toughened and augmented enables successful mission completion in the face of significant GPS jamming and spoofing.

The post BAE Systems White Paper: APNT for UAVs and Loitering Munitions appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

BAE Systems’ recent white paper proposes a Common APNT Package (CAP) to meet these threats head-on.

To gain deeper insight into the thinking behind the paper, Inside GNSS spoke with Mike Shepherd, Director of APNT Strategy at BAE’s Navigation and Sensor System’s Business of BAE Systems. What emerged from that conversation is a layered, modular and verifiable system for achieving assured PNT in the most demanding operational environments.

REDEFINING MISSION SUCCESS WITH CPSM AND QUADRANT D

“Quadrant D—precision absolute PNT—is not a luxury; it’s essential,” Shepherd said. Defined by <10m positional error and <1ms timing error, Quadrant D supports full mission capability across all UAV operations.

Arriving at this framework was no small task. “We weren’t just trying to document requirements. We asked, ‘What’s the real problem here?’ And the answer was simple: Successful mission completion. Not partial. Not degraded—successful.”

This internal reset led to a shift in evaluation metrics. Cost Per Successful Mission (CPSM) became the standard by which effectiveness would be judged. “Every program has a unit cost target,” Shepherd noted, “but if you’re flying a $30k drone and it fails because it lost PNT five minutes in, your CPSM just skyrocketed. That failure costs more than the airframe.”

MERGED MODALITIES: A UNIFIED APNT THREAT RESPONSE

From that mission-first mindset, BAE turned to the question of how to maintain PNT under diverse, overlapping threats. Rather than investing in one dominant sensor type, they are developing a hybrid strategy that leverages the complementary failure modes of GPS/SATNAV and vision-based navigation.

“We realized that vision-based systems degrade for totally different reasons than GPS,” Shepherd explained. “So, if you build an architecture that leans on both, they rarely fail simultaneously. That’s the sweet spot.”

Shepherd reinforced this point by describing real-world use cases. “During a GPS outage—say from jamming, canyoning or terrain masking—vision can carry the load if it has a reliable clock and initialization. It can’t start cold in fog or total darkness. That’s where GPS or even Alternate Navigation systems come in.”

Importantly, this approach is sensor-agnostic but rigorously integrity-driven. “If a sensor can prove itself in the Integrity Ring,” Shepherd said, “then it’s a candidate. It’s not about preference—it’s about credibility.”

ASSURED SENSOR FUSION AND THE INTEGRITY RING

This focus on credibility led to one of the white paper’s core concepts: the Integrity Ring. Rather than simply fusing data from multiple sensors, BAE’s system actively validates each sensor’s input before including it in the final PNT solution.

“We don’t just fuse—we verify,” Shepherd said. “This isn’t a statistical mean. It’s a vetted synthesis. If a sensor starts to diverge from the consensus, we identify and exclude it.”

Shepherd elaborated on the metaphor: “It’s like a courtroom. Each sensor provides testimony, but the Integrity Ring is the judge. It asks: ‘Does this align with the rest of the evidence?’ If not, that sensor’s out.”

This adjudication mechanism enables change to…“multi-sensor PNT integrity, which allows us to use all available signals (even open service GNSS for example) while maintaining high trust in the PNT solution. 

“You know where you are, you know what time it is, and you’re ready to reacquire when the environment allows,” Shepherd explained. “That’s a powerful place to be when GPS is denied.”

MODULARITY AND SCALE: COMMON APNT ACROSS ALL CLASSES

The Integrity Ring and its surrounding architecture are not limited to large platforms. In fact, the CAP concept was developed with scalability in mind. Rather than embedding PNT logic in each payload, BAE advocates for a platform-level architecture shared across all mission variants.

“We’re not pushing a $50K box for a $5K drone,” Shepherd said. “We’re scaling the same architectural logic across all classes, from expendables to Group 5 UAVs, using modular components and common interfaces.”

This modularity aligns tightly with the Department of Defense (DoD)’s push for a Modular Open Systems Architecture (MOSA). Shepherd noted the added benefit of continuity in an acquisition environment marked by rapid leadership turnover. 

“Program leads change every 12 to 18 months. Without a standard, you’re reinventing the wheel with every rotation. CAP creates that consistency.”

Shepherd pointed to existing prototypes as proof of concept. “We’ve got “MILGPS” based systems flying today in many precision weapons. They’re meeting, or exceeding jamming and spoofing requirements.”

SURVIVABILITY IN A JAMMED AND SPOOFED BATTLESPACE

All of these architectural choices converge on a single battlefield reality: the need to operate in the presence of adversarial interference. In the white paper, BAE modeled identified benefits of M-Code and AJ/AS techniques. The results are dramatic.

GPS receivers can be rendered inoperable while still a significant distance from the interference source. In contrast, modern CAP-equipped UAVs with antijam (AJ) antennas and M-Code capability can retain full Quadrant D precisionfor operation closer to the interference.

Real world scenarios are even more urgent. “We’ve seen in Ukraine that fiber-optic cable is being laid across contested terrain—not because of bandwidth demand, but because RF is being jammed,” Shepherd said. “If that doesn’t underscore the need for assured PNT, I don’t know what does.”

To counter spoofing, the CAP system includes multiple defense layers: M-Code authentication, radio frequency (RF) anomaly detection, cold-start checks, and cross-sensor validation. “We’re not betting on any single trick,” Shepherd emphasized. “We’re building a robust web of trust.”

ARCHITECTING FOR THE FIGHT WE KNOW IS COMING

The Common APNT Package isn’t simply a technical response to a sensor problem—it’s a system-level rethink of how PNT is delivered and trusted in the most hostile environments imaginable.

“Don’t wait for the threat to teach you the lesson,” Shepherd warned. “Assured PNT isn’t about redundancy—it’s about integrity. And that has to be built in from the start.”

Shepherd, with a final call to action: “We’re saying: Start with the threat, build for survivability, and make integrity the default. The white paper is a blueprint. Adapt it. Build on it. But don’t ignore it.” 

The post Precision Under Fire: BAE Systems Advances Assured PNT (APNT) for UAVs and Loitering Munitions appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

For Oleg Khaykin, President and CEO of VIAVI Solutions, the company’s recent acquisitions in positioning, navigation and timing (PNT) represent more than tactical expansion—they mark a strategic alignment with the evolving demands of modern defense and infrastructure. In an era shaped by contested signals, electronic warfare (EW) and autonomy at the edge, VIAVI is building a platform that not only withstands disruption but is engineered to operate through it.

“The acquisition of Jackson Labs Technologies [JLT], combined with Inertial Labs, positions VIAVI as a leader in the resilient PNT space,” Khaykin explained. “We now offer complementary technologies that enable us to provide complete solutions addressing the entire PNT signal chain—from signal generation and distribution to detection and validation.”

This “signal chain” view of PNT is central to VIAVI’s thesis. Inertial Labs contributes leading sensor fusion and visual navigation capabilities. Jackson Labs brings high-performance timing, holdover stability, and signal conversion through its transcoder platform. But what matters most is how these components function as part of a reconfigurable system.

“By bringing together the precision timing technologies of Jackson Labs with the inertial navigation solutions from Inertial Labs, we have created a comprehensive PNT portfolio that few others can match,” Khaykin said. “This is especially important in applications where GNSS signals are degraded or denied.”

Khaykin was direct about the evolving threat environment: GPS signals, once assumed secure, are now routinely denied, spoofed or degraded—particularly in peer or near-peer conflict zones.

“The growing threats to GPS—both accidental and deliberate—require a new approach to PNT,” Khaykin continued. “VIAVI is addressing this challenge by delivering modular, interoperable and scalable solutions that support multiple layers of PNT resilience.”

This platform mindset builds on VIAVI’s long-standing strengths in test, validation and network visibility, now applied to navigation and timing environments.

“Our heritage in test and measurement means we understand how to ensure performance, reliability and interoperability in complex systems,” he said. “This gives us a unique advantage as we scale PNT solutions across both defense and commercial applications.”

And while national security applications remain a primary focus, Khaykin noted the demand for resilient, verifiable time and navigation is growing rapidly in civilian sectors as well.

“Resilient timing and navigation are becoming essential for critical infrastructure, telecommunications and emerging autonomy markets,” he said. “VIAVI is building the technology foundation to meet those needs.”

EDGE ENGINEERING: VIAVI AND INERTIAL LABS

VIAVI’s strategic vision is built on more than acquisition—it’s about integration with purpose. That vision becomes tangible through VIAVI’s collaboration with Inertial Labs, where the emphasis is on engineering at the edge: leveraging onboard sensors, reusing existing hardware, and delivering GNSS-resilient capabilities through sensor fusion, visual odometry, and precise time alignment.

What sets VIAVI apart is not just its ability to survive signal denial—but its modular, sensor-fused approach that adapts to each mission’s constraints and maximizes what’s already onboard.

The Challenge: GNSS Vulnerability and the Path to Resilience

In an era where EW saturation and GPS denial are no longer hypothetical but expected conditions of the battlefield, traditional PNT systems are struggling to keep pace. Doug Russell of VIAVI captured the sentiment succinctly: “Even in a GPS-denied environment, our integrated systems can still provide a robust signal that looks like GPS for the rest of the vehicle’s systems to operate. That is a huge cost and capability advantage.”

The operational landscape now assumes degraded or denied environments as the baseline. M-Code, low Earth orbit (LEO) constellations, and alternate navigation strategies are being prioritized by U.S. Department of Defense (DoD) modernization efforts and critical infrastructure entities alike. The need for layered, modular and cost-effective solutions is pressing.

Built for the D3SOE: Resilience by Design

Today’s mission planners no longer treat GNSS degradation as a possibility—they expect it. The DoD defines this new normal as the D3SOE: Denied, Degraded and Disrupted Space Operational Environment, where contested signals, spoofing and jamming are routine, not the exception.

VIAVI’s integrated PNT platform is purpose-built for this environment. With components that interoperate across GNSS, inertial, visual, RF, and holdover timing domains, the system provides multiple, redundant pathways to maintain trusted PNT. By embedding resilience at every layer—from edge sensor fusion to transcoder-based retrofits—VIAVI ensures users can operate confidently, even when space-based signals are compromised.

This is not just survivability under threat—it’s assured performance, engineered for contested space from the start.

Integration as Differentiator: A Platform Built for Modularity

Jamie Marraccini, CEO of Inertial Labs, explained: “We start with what the platform already has—radios, cameras, antennas—and reuse that data. That means better SWaP-C and faster integration, especially for UAVs and expeditionary systems.”

Russell emphasized how this vision translates into practice: “For any given engagement, customers might need a GNSS receiver, maybe M-Code, maybe not. They might prioritize holdover clock performance or sensor fusion accuracy. What we provide is a menu of capabilities that the customer can build from—tailored to their mission set.”

Perhaps the most novel approach from the Inertial Labs side is their philosophy of sensor reuse. “A camera, already onboard for visual targeting or surveillance, can double as an input for visual navigation,” Marraccini said. “That is savings in both cost and power. Same goes for radios—
already on the platform for comms, but also usable for positioning via time-of-flight measurements.”

This reuse-centric design not only improves SWaP-C but also accelerates deployment timelines by reducing integration complexity.

One of the standout elements in this platform is the transcoder. “It allows you to disconnect an antenna and connect the output of the transcoder,” Marraccini said. “To the legacy system, it appears as a standard GPS L1 signal—but what it’s actually receiving is resilient, reconstructed navigation data.”

Russell added: “From a cost standpoint, that’s enormous. You’re upgrading without retrofitting the whole platform.” The transcoder outputs GPS-compliant signals derived from GNSS, inertial and even visual navigation inputs, enabling legacy platforms to function effectively in contested environments. What makes this platform especially future-ready is the decision to push processing and data alignment capabilities to the edge.

Marraccini noted: “We offer all time-stamped data to customers. They can use our fusion engine or run their own. We also provide access to synchronized data streams, allowing them to control how that data is exported to other systems.”

Time-stamping and physical alignment between sensors are critical for high-precision navigation. “If you’re 2,000 meters up and your camera and IMU aren’t aligned, you could be off by tens or hundreds of meters on the ground,” Marraccini said. “We calibrate the camera, IMU and magnetometer as one unit to ensure perfect alignment.”

This results in visual geolocation accuracy of 5 to 25 meters in most scenarios—without GNSS. Timing accuracy, meanwhile, can fall well below 100 nanoseconds, depending on the configuration. “We’re squeezing every ounce of performance out of the sensor and timing systems,” Russell said. “It is the compounded value of incremental improvements.”

The architecture accommodates inputs from M-Code, GEO, MEO and LEO constellations. Marraccini emphasized, “We’re the only company doing time acquisition from LEO, MEO and GEO 
simultaneously.” That capability enables robust holdover performance and diverse signal acquisition, significantly boosting system resilience.

Holdover clocks are configurable by application—ranging from basic solutions to CSAC-level timing stability. Said Jackson’s custom algorithms, developed at JLT, discipline these clocks for optimal performance.

The deeper the integration goes, the more apparent the value becomes. “We’ve found instances where a customer was already using Inertial Labs and Jackson Labs products independently—unaware that we are now part of the same ecosystem,” Russell said. “Now, we can remove redundancies, improve SWaP and reduce total system cost—all while boosting performance.”

While military applications remain a central focus, VIAVI’s platform is clearly dual-use. “The same resilience that matters in a GPS-denied battlefield also matters for first responders, utilities and transportation networks,” Marraccini said. “And now, we are not just talking about defense-grade performance. We’re making that available at a price point suited for commercial and civil applications.”

Russell and Marraccini consistently returned to the value of open architecture. “MOSA [modular open systems approach] allows customers to define their solution, using our fusion engine or plugging in their own,” Russell explained. “They’re not locked into a black box.”

That customer-first, open integration approach has become a defining feature of VIAVI’s strategy. “Whether they want to use our cameras, or theirs, our radios or theirs, our mission is to empower the integrator,” Marraccini said. “Everything we do is modular by design.”

PROVING GROUND: OPERATIONAL VALIDATION AT WHITE SANDS

As Inertial Labs pushes the boundaries of edge-based integration and sensor fusion, VIAVI’s broader platform must still prove its resilience under real-world conditions. That validation came in the New Mexico desert, where VIAVI deployed its full PNT suite against some of the most advanced jamming and spoofing threats in use today.

At NAVFEST—conducted by the U.S. Air Force’s 746th Test Squadron at White Sands Missile Range (WSMR)—VIAVI’s integrated PNT system was subjected to a series of mission-representative scenarios designed to emulate the EW conditions of a modern battlespace. The objective was clear: validate that VIAVI’s modular, multi-layered architecture could deliver assured PNT under threat, confirming not just technical soundness but full operational readiness for deployment across joint and contested environments.

The following section draws on insights from three key leaders—Marv Rozner, Senior Director of Military Programs and Synthetic Products at VIAVI; Said Jackson, founder of Jackson Labs and now VIAVI Vice President; and Giovanni D’Andrea, VIAVI Senior Director of Business Development—who were directly involved in the effort.

A New Architecture for PNT: Mission-Driven, Not Tech-Driven

One of the central themes emphasized by all three leaders was a departure from technology-first thinking toward mission-first design. “We don’t want to block our customers into a corner,” Jackson said. “We want to provide capabilities that do not lock them into a particular ecosystem. All of our products are orthogonal to each other. If you want to buy your GNSS receiver from someone else, you can.”

The team explained that the combined VIAVI platform offers customers a flexible mix of high-performance PNT components—from holdover timing to inertial navigation to GNSS receivers—that can be mixed and matched based on the requirements of the mission, platform or budget.

“It is not about throwing the most expensive IMU or rubidium clock at every problem,” Rozner said. “It’s about delivering the level of capability that the CONOPS requires.”

Rozner underscored the team’s commitment to open standards and modular design: ”Our new platforms are modular, utilizing an M.2 form factor—delivering standardized, high-speed, compact interfaces used in billions of devices annually. That allows us to scale a platform from a handheld unit to a tank.” Jackson elaborated, noting the goal is to enable plug-and-play interoperability not just within their ecosystem, but with any standards-compliant architecture. “Whether you’re building a low-SWaP UAV system or upgrading an Abrams tank, we are designing subsystems that can slot in and scale up or down.”

A centerpiece of JLT’s contribution to the VIAVI platform is the transcoder—a software-defined module that bridges incompatible systems in a secure and scalable way. Originally conceived in 2015 to address the Army’s challenge of retrofitting tens of thousands of dismounted GPS units without depot-level upgrades, the transcoder is now widely adopted across tier-one defense programs.

“We essentially insert a smart antenna in front of the legacy receiver,” Jackson said. “It looks like a standard GNSS antenna to the host system, but it’s actually feeding corrected, authenticated, M-Code-capable or spoofing-resistant data. The soldier swaps an antenna, not a manpack.”

D’Andrea added, “This allows us to upgrade billions of dollars of fielded gear in minutes instead of months. That matters.”

JLT’s reputation was built on world-class timing. As Jackson noted, “We’ve been improving timing since 2005. We took rubidium, MEMS and cesium clocks and made them better. Today, we offer 1 to 5 nanosecond timing accuracy using L-band correction data—without a cesium price tag.”

Rozner emphasized that timing remains the bedrock of the entire system. “Without the ‛T’, the ‛P’ and ‛N’ do not matter.”

JLT’s approach includes GNSS spoofing authentication using ground-based verification systems, as well as dynamic fallback to holdover timing in contested environments. Their upcoming Ku-band capabilities and L-band services add further layers of resilience.

With the integration of Inertial Labs, VIAVI can now offer a full stack of PNT capability. The platform adds visual odometry, IMUs and sophisticated sensor fusion to the mix. The result is not just redundancy, but enhanced awareness.

“We can detect spoofing through signal analysis and motion inconsistency,” Rozner said. “If the visual and inertial systems say one thing and GNSS says another, we know something’s wrong.”

D’Andrea expanded on the benefit: “It is not just about survivability. It is about giving customers options. We can mix-and-match the best of each capability to meet their operational needs.”

When asked about their edge in performance, Jackson said, “It is all about optimization. We design our own IP. We write the software from scratch. We don’t just take reference designs from vendors. That gives us flexibility to squeeze every ounce of performance out of these integrations.”

Rozner echoed the point, highlighting that the company’s software-defined radio (SDR) heritage plays a crucial role. “Everything from our L-band timing services to our Ku-band receivers are running on the same SDR hardware. That is why we can pivot faster and deliver more with less.”

VIAVI and JLT are designing their ecosystem to meet a spectrum of needs, D’Andrea said. “We’re building a hub of core technologies that can serve everyone from a first responder to a SOCOM operator. That is what Transcoder 2.0 is about—you pick the INS you want, the level of holdover you want, the GNSS you need.”

Rozner summarized the philosophy: “Whether it’s a $300 timing module or a full-up PNT subsystem for a vehicle, we want to give the customer what they need without forcing them to buy what they do not.”

VIAVI | JLT remains the only known provider using ground-based infrastructure to authenticate GNSS signals outside the network itself. This complements spoofing detection and fallback protocols across the VIAVI platform.

“We believe spoofing detection is the first problem to solve,” Jackson said. “If you cannot detect spoofing, then nothing else matters. Once you know, then you can fall back to our trusted timing or switch to authenticated sources.”

All three leaders agreed: VIAVI’s platform is not just a new product. It is a modular, standards-based architecture for delivering PNT resilience at scale. With IP ownership across timing, navigation and integration layers, and a pricing model built around COTS efficiencies, the company believes it is uniquely positioned to lead the next era of assured PNT.

“We do not just future-proof our solutions,” Rozner said. “We future-proof our customers.”

While the field trials at White Sands demonstrated the VIAVI platform’s resilience under electronic attack, the real innovation lies in how those capabilities are architected from the ground up. 

Compound Gains Through Collective Innovation

What VIAVI and its subsidiaries have created is not just an amalgamation of parts—it’s a precision-engineered system where each improvement is magnified by the next. The combined capabilities of Jackson Labs, Inertial Labs and VIAVI offer customers a foundation that scales from platoon-level kits to enterprise-wide PNT infrastructures.

“We build capability at the pace of operational need,” Russell said. “And increasingly, that means making smart use of what’s already there, integrating it with the best we can build, and delivering it in a form that works right now—not in five years.”

From holdover timing to georeferenced vision, and from transcoder-based 
retrofits to edge-fused intelligence, VIAVI’s integrated PNT platform stands ready to meet the evolving challenges of GNSS resilience with ingenuity, adaptability and performance.

Layers of Reliability: An Engineered Advantage

This cohesion is no accident. Once independent centers of excellence, Jackson Labs and Inertial Labs are now fully embedded within VIAVI—not as acquisitions, but as integral innovation hubs aligned under a unified operational vision. Their fusion brings more than just expanded capabilities—it adds depth, agility and resilience across the platform.

Leveraging Inertial Labs’ robust aiding data ecosystem, VIAVI’s integrated PNT architecture builds layers of reliability that sustain performance even under the harshest GNSS-denied conditions. Each element—visual, inertial, RF, and timing—reinforces the next, forming a tightly coupled web of complementary technologies. This multi-layered approach does not just guard against signal loss; it ensures bounded absolute position accuracy through redundancy, adaptability and smart sensor fusion.

With this foundation, VIAVI delivers more than an alternate to GNSS—it delivers operational assurance. The result is a system built for today’s contested environments and tomorrow’s evolving threats.

A Unified Vision, Proven in the Field

Taken together, these three perspectives reveal a consistent thread in VIAVI’s approach to resilient PNT: a CEO’s vision for unified capability, a field team’s validation under real-world EW conditions, and an engineering ethos grounded in modularity, reuse and intelligent integration. Khaykin’s strategy is more than aspirational—it’s operational, as demonstrated by the team’s performance at WSMR.

That performance is no coincidence. It reflects a deliberate, layered framework engineered by Jackson Labs and Inertial Labs and now fully realized within VIAVI. From executive leadership to ground-level deployment, VIAVI is aligning innovation with mission urgency—delivering the kind of trusted PNT foundation that modern operations not only require, but increasingly demand. 

The post Assured Advantage: VIAVI’s Integrated Vision for Positioning, Navigation, and Timing appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

Global Navigation Satellite Systems (GNSS) underpin modern positioning, navigation and timing (PNT), enabling precise positioning for applications ranging from aviation and autonomous driving to logistics and infrastructure monitoring. However, GNSS spoofing—a technique where attackers manipulate positioning data to mislead receivers—has become an increasing threat. Once considered a niche concern, spoofing incidents are now rising because of the availability of low-cost software-defined radios (SDRs), open-source spoofing tools, and their increasing use in geopolitical conflicts.

The impact extends beyond military targets and into commercial aviation, autonomous driving and logistics, where secure and reliable positioning is critical. Recent events underscore the severity of this issue. GNSS disruptions in Ukraine have reportedly been used to jam and mislead military drones and aircraft, as well as commercial vessels navigating the Black Sea. In the Middle East, airspace over Lebanon, Syria, Jordan and Israel has experienced GNSS anomalies, forcing pilots to switch to alternative navigation methods and raising concerns over aviation safety in the region.

While these attacks often target aerial and maritime navigation, their effects extend to ground-based positioning as well. GNSS-dependent systems—including autonomous vehicles, industrial robots, and fleet management solutions—can experience severe disruptions if spoofed signals cause drift, position jumps, or complete navigation failures.

To understand the full scope of GNSS spoofing, this article examines four major categories of spoofing attacks:

• RF spoofing at receivers: Directly misleading user devices.

• RF spoofing at Continuously Operating Reference Stations (CORS): Compromising reference stations to distribute false corrections.

• Correction data tampering: Intercepting and modifying correction streams.

• Server data injection: Injecting false GNSS observations into correction processing servers.

We will explore how GNSS correction services like Swift Navigation’s Skylark Precise Positioning Service play a vital role in mitigating spoofing attacks and securing navigation systems against the growing risk of signal manipulation. Skylark is a real-time, cloud-based GNSS correction service designed for accuracy, reliability and safety at a global scale.

Using proprietary atmospheric modeling, Skylark corrects GNSS errors caused by ionospheric disturbances, clock drift and orbital inaccuracies, improving positioning precision from several meters to just a few centimeters. Its carrier-grade network of reference stations is built and operated in partnership with mobile network operators who secure and maintain them as critical infrastructure, including their backhaul connectivity. By continuously validating satellite data and leveraging its secure, AWS-based cloud infrastructure, Skylark detects and rejects spoofed signals before they can impact users, ensuring robust and trustworthy positioning in contested environments.

Tap or hover to reveal how Swift detects and defeats spoofing attacks:

RF SPOOFING AT RECEIVER: DIRECTLY ATTACKING USER GNSS EQUIPMENT

Attack Overview

RF spoofing involves broadcasting counterfeit GNSS signals to override real satellite transmissions. This can mislead standalone receivers in vehicles, aircraft or mobile devices into computing incorrect positions. 

The most basic approach is meaconing, a passive form of RF spoofing that replays genuine GNSS signals without modification. This technique does not require the attacker to generate satellite navigation data—only to record and rebroadcast it. 

More elaborate approaches involve generating new, artificial GNSS signals rather than replaying old ones. This requires:

• Custom signal generation: Attackers must create satellite-like signals that match the expected structure while leading the receiver to a false position or time. This includes using the most up-to-date real ephemerides to maintain credibility.

• Real-time adaptation: To effectively spoof a moving target, attackers must continuously adjust the spoofed signal’s timing and Doppler shift, mimicking real satellite motion. Where motion sensors are included in an integrated solution, the spoofing must also mimic the actual motion of the target as observed by the sensors.

• Multi-frequency complexity: High-end receivers rely on multiple GNSS signals (L1/L2/L5, multi-constellation), making it exponentially more difficult to spoof all of them consistently.

Regardless of the method, RF spoofing typically involves amplifying the counterfeit signal to overpower authentic GNSS signals while also jamming unspoofed frequencies, forcing the receiver to track the spoofed signal.

Possible Defenses 

• Authenticated ephemeris: Advanced correction services, such as Skylark, provide verified ephemeris data, allowing receivers to detect mismatches between real and spoofed signals.

• Sensor fusion: If GNSS-based velocity and position contradict IMU and odometry data, a sophisticated positioning engine, such as Swift Navigation’s Starling PE, will identify the inconsistency and report the event. 

• Multi-constellation protection: Spoofing multiple GNSS systems simultaneously is extremely difficult. High-end receivers validate signals across multiple constellations, prioritizing trusted signals and rejecting anomalies.

• Future authentication measures: Services like Galileo Open Service Navigation Message Authentication (OSNMA) will allow receivers to cryptographically verify that ephemeris data originates from authentic satellites, making spoofing even more difficult. 

RF SPOOFING AT CORS: ATTACKING GNSS REFERENCE STATIONS

Attack Overview

Instead of targeting a single user device, an attacker could spoof GNSS signals at a CORS used in correction services such as Real-Time Kinematic (RTK). This could result in the widespread distribution of erroneous corrections, impacting industries such as autonomous navigation, land surveying, and fleet management—
potentially causing significant financial and operational disruptions.

A compromised CORS also could enable more targeted attacks, such as misleading law enforcement tracking, manipulating high-frequency trading timestamps, or disrupting a competitor’s GNSS-based services.

An attacker can spoof a CORS by manipulating different aspects of the GNSS signals it receives. While large deviations in a station’s reported position are easily detected—because its location is fixed and known—more subtle attacks can be more difficult to identify. By modifying satellite ephemerides and clock data while keeping the CORS’s reported position unchanged, an attacker can introduce hard-to-detect errors that propagate through correction streams, misleading all users dependent on that station’s corrections.

Possible Defenses 

• Position anomaly detection: Skylark can detect subtle deviations in a CORS reported position and will flag it as compromised.

• Automated station quarantine: Skylark isolates compromised stations from its correction model while maintaining performance through its network of redundant reference stations.

• Ephemeris voting mechanism: Skylark cross-validates ephemerides across its network of reference stations, rejecting outliers that do not align with network consensus.

• Continuous clock monitoring: Skylark tracks GNSS clock biases in real time; unexpected deviations trigger station quarantine to prevent bad corrections.

CORRECTION DATA TAMPERING: INTERCEPTING AND MANIPULATING GNSS CORRECTIONS

Attack Overview

Instead of spoofing RF signals, an attacker could intercept, modify or inject false GNSS corrections before they reach a receiver. This type of attack can introduce positioning errors without disrupting GNSS signals, making it stealthier than RF spoofing.

Corrections transmitted over unsecured channels, such as unencrypted IP connections or open radio links (e.g., RTCM over VHF/UHF), are particularly vulnerable. Attackers can:

• Block or delay corrections to degrade service (denial-of-service attack).

• Inject false corrections to subtly manipulate positioning solutions.

• Impersonate a legitimate correction provider to distribute incorrect data.

These attacks borrow heavily from cyber-attack techniques, including man-in-the-middle (MITM), packet injection and data spoofing. Just like RF spoofing of reference stations, correction data tampering can lead to significant financial and operational disruptions across industries that depend on high-accuracy GNSS, such as autonomous systems, precision agriculture and infrastructure monitoring.

Possible Defenses

• Encrypted corrections: Skylark secures correction data with encryption, preventing interception and modification by unauthorized parties. 

• Authentication and integrity checks: Digital signatures ensure corrections originate from a trusted source and have not been altered in transit.

• Tamper-resistant transport: Skylark transmits corrections over secure, authenticated channels, reducing vulnerability to man-in-the-middle attacks.

• Fallback mechanisms: If corrections fail integrity checks, the receiver disregards them and switches to raw GNSS or dead reckoning.

SERVER DATA INJECTION: COMPROMISING GNSS OBSERVATIONS SENT FOR PROCESSING

Attack Overview

An attacker could inject false GNSS observation data directly into the servers responsible for computing corrections, leading to the widespread distribution of erroneous data. This network-based attack—distinct from RF spoofing—poses significant risks to industries reliant on high-precision positioning, such as 
autonomous systems, construction and logistics. Correction services with weak cloud security and data integrity measures are particularly vulnerable.

Possible Defenses 

• Secure cloud infrastructure: Skylark runs on Amazon Web Services (AWS), leveraging its built-in encryption, identity management, and network security to safeguard correction data.

• Diversified compute environments: Skylark concurrently uses ARM-based (Graviton) and x86 AWS instances, reducing the risk of single-architecture vulnerabilities.

• Geographically distributed redundancy: AWS Availability Zones provide fault isolation, preventing localized disruptions from affecting the entire correction network.

• ISO 26262-certified safety: Skylark complies with automotive safety standards, ensuring correction services remain secure and functionally safe under stringent reliability requirements.

CONCLUSION

GNSS spoofing is no longer a theoretical risk—it is a rapidly evolving threat that affects aviation, autonomous systems, logistics, and other industries that depend on precise positioning. As spoofing incidents rise due to geopolitical conflicts and the availability of low-cost tools, implementing robust countermeasures is essential to ensure accuracy, reliability and security in GNSS-based navigation.

Swift Navigation’s Skylark Precise Positioning Service is a proven solution for mitigating spoofing threats, delivering secure, high-accuracy GNSS corrections. By leveraging network-validated ephemeris, real-time anomaly detection and quarantining, encrypted correction streams, and a cloud-based security architecture, Skylark ensures trusted GNSS data—even in contested environments.

Available in three variants—Nx RTK, Cx and Dx—based on Virtual Reference Station (VRS) RTK, PPP-RTK, and Differential GNSS (DGNSS), Skylark is optimized for specific applications, balancing accuracy, coverage, complexity, and cost, with precision ranging from 1 cm to 1 meter. Trusted by leading automotive OEMs, Tier 1 suppliers, robotics companies, IoT system integrators, and mobile handset OEMs, Skylark powers more than 10 million Advanced Driver-Assistance System (ADAS) enabled and autonomous vehicles and devices worldwide.

Learn more about Skylark at swiftnav.com, and contact Swift Navigation for expert guidance on securing your precise positioning application in a spoofing-prone world. 

The post Swift Navigation Skylark™️ Precise Positioning Service: Defending Against Spoofing with GNSS Corrections appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

In a recent conversation with Inside GNSS, Tzeno Galchev, director of MEMS marketing at Analog Devices, offered insight into the next-generation capabilities of the ADIS16576 IMU and what sets it apart in a competitive landscape.

A LEAP FORWARD IN MEMS IMU PERFORMANCE

“The ADIS16576 offers a substantial leap forward in core sensor performance,” Galchev said. One of the most impressive advancements is its dramatically reduced vibration rectification error (VRE): a 10x improvement in gyroscope VRE and a staggering 50x improvement in accelerometer VRE compared to previous models. This is particularly significant because VRE has long been a limiting factor in high-precision navigation and stabilization applications. VRE-induced errors can compromise gyroscope bias stability and skew accelerometer outputs, leading to guidance anomalies, particularly in UAVs operating under intense vibrational conditions.

Another major innovation is the inclusion of a crystal oscillator—making the ADIS16576 the first compact MEMS IMU to incorporate one. This addition enhances sample clock precision by more than 100 times, allowing for more consistent and synchronized data acquisition. For developers working on tightly coupled navigation systems, this precision translates directly into improved state estimation and better overall performance.

The ADIS16576 also boasts a 10x increase in serial communication throughput, a deep FIFO buffer of 512 samples per sensor, and significantly expanded diagnostics—all of which combine to offer a MEMS IMU that delivers not only performance but also ease of integration.

SIMPLIFYING INTEGRATION THROUGH FACTORY CALIBRATION

One of the recurring challenges developers face is the time and cost involved in calibrating IMUs for a specific system or platform. Analog Devices has tackled this head-on with an advanced factory calibration process that eliminates the need for exhaustive, temperature-varied motion profiles during system integration.

“ADI’s factory calibration process is one of the most important ‘ease of use’ features in the ADIS16576,” Galchev explained. “In many cases, AGV/UAV platforms can align the ADIS16576 with their inertial reference frames using very simple motion profiles, at a single temperature.”

Customers have reported this feature alone has saved them more than two years of test development time, which can translate to over $2 million in capital expenses, Galchev said. Moreover, what once took hours can now be accomplished in minutes, significantly increasing production capacity and reducing time to market.

UNDERSTANDING THE SIGNIFICANCE OF VRE

Vibration rectification error may sound esoteric, but its implications are concrete and consequential. “In accelerometers, it directly impacts initial attitude estimates as a UAV is powering up,“ Galchev noted. ”In gyroscopes, VRE represents a rapid change in gyroscope bias, which can trigger erroneous maneuvers in a UAV’s guidance navigation control [GNC].”

Poor VRE performance can limit the environments a UAV can safely operate in, especially when faced with the high-vibration environments common to rotorcraft and fixed-wing drones. By minimizing VRE, the ADIS16576 provides a level of robustness that opens the door to broader and more demanding use cases.

BUILT FOR EXTREME CONDITIONS

The ADIS16576 is engineered to operate reliably across a wide range of temperatures and shock conditions. With full calibration coverage across the industrial temperature range of -40°C to +85°C, it enables UAVs and AVs to perform consistently at high altitudes and in varied geographies throughout the year.

Shock survivability is another strength of the device, enhancing durability during handling, assembly and even minor in-field collisions. For platforms designed to operate in harsh or unpredictable environments, this ruggedness is more than a bonus—it’s essential.

STREAMLINED COMMUNICATION AND DATA INTEGRITY

The SPI-compatible data communication interface in the ADIS16576 is optimized for embedded system integration. ”Most embedded processor platforms support SPI with dedicated ports and a simple set of configuration commands,“ Galchev said. By expanding the maximum serial data rates, the ADIS16576 reduces system communication overhead by a factor of seven compared to previous-generation IMUs.

Furthermore, improvements in error detection and recovery reduce disruptions caused by electromagnetic interference (EMI), making the unit more reliable in electrically noisy environments. These enhancements make integration faster, simpler and more robust.

REAL-TIME HEALTH MONITORING FOR SAFER AUTONOMY

As autonomy becomes more prevalent, the demand for real-time system health monitoring has surged. ”Most application spaces are requiring increasing levels of error detection and recovery,“ Galchev observed. The ADIS16576 delivers on this front with both continuous and user-initiated diagnostic checks covering all six inertial sensors and multiple memory blocks.

It also includes tools to validate communication integrity, verify flash memory storage, detect processor overruns, and initiate resets when necessary. These diagnostics are vital for ensuring operational safety, especially in safety-critical control GNC functions of autonomous platforms.

A SMARTER IMU FOR A SMARTER WORLD

With the ADIS16576, Analog Devices has pushed the boundaries of what’s possible in compact MEMS IMUs. From breakthrough vibration rejection and sample clock precision to user-friendly calibration and robust diagnostics, this device is a true step forward in enabling safer, more efficient and more precise autonomous systems.

As developers seek solutions that minimize integration complexity while maximizing performance, the ADIS16576 stands out as a powerful tool for building the next generation of UAVs, AGVs and other intelligent platforms. It’s not just an incremental improvement—it’s a new benchmark for what MEMS IMUs can deliver

The post Precision, Performance and Integration: Analog Devices Sets A New Standard for MEMS IMUs appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

Since 2015, controlled reception pattern antennas (CRPAs) have emerged in the civil applications market, where the need to combat GNSS signal jamming and spoofing has grown exponentially. Previously available only to authorized military users, these powerful antennas can significantly increase resiliency for many GNSS applications, from aviation to critical infrastructure to autonomous vehicles and drones to the monitoring of heavy-duty freight shipments. 

As a particular example, consider Galileo Public Regulated Service (PRS) receivers aboard navigation systems and platforms, equipped with GPS/Galileo-compatible CRPAs. Galileo Open Service (OS) receivers in sensitive applications such as drone flights and other autonomous navigation will likely also require such interference-rejecting capability.

While new CRPA prototypes and products proliferate over the coming years, the need for advanced simulation and testing capabilities for them will steadily increase, as well as the need for evolving test methodologies. The capability to manufacture CRPAs with low-cost hardware serves to further extend their potential applications, and to complicate scenarios for which they must be tested.

To ensure reliability and integrity, CRPA systems must be thoroughly tested in a range of scenarios, using varied testing methodologies. This presents significant challenges for both the testers and the product design, engineering and integration teams. Specialist knowledge and expertise are de rigueur.

For 22 years, M3 Systems has specialized in tests and measurements, innovating with precision and passion under rigorous requirements and in challenging test scenarios. M3 Systems offers advanced solutions in laboratory-controlled testing, simulation solutions, record and playback solutions and hybrid approaches.

Why CRPA? And How?

GNSS is very vulnerable to signal interference, both intentional—such as jamming, spoofing and meaconing—and unintentional. As jamming, spoofing, and meaconing techniques have grown more and more sophisticated and far more frequent, the existing GNSS interference rejection techniques have not proved sufficient to combat them.

CRPA is a state-of-the-art solution to interference rejection, intentional as well as unintentional. The multiple antenna elements that can be controlled individually (thus the term “smart antenna”) detect the presence of interference signals and adjust the elements’ reception patterns to minimize or eliminate RFI impact. 

CRPA options include antenna null forming in the direction of the antenna source, beam steering to direct gain towards genuine signals, minimum variance distortionless response and more. Naturally, CRPA simulation and testing must exhibit a similar state-of-the-art quality in order to offer a means towards CRPA implementation in the GNSS product chain.

All new systems incorporating these new-capability antennas must be thoroughly vetted, at every stage of product development, against revamped vulnerabilities. M3 Systems has a thorough background in efficient radio-frequency interference (RFI) simulation testing, including modeling the interfering transmitters and simulating moving interfering transmitters.

In addition, such testing should take into account the potential impacts of new signal authentication schemes, already underway with Galileo’s Open Service Navigation Message Authentication (OSNMA) and future testing of GPS modernization proposal to take place aboard the NTS-3 satellite, namely Chips Message Robust Authentication (CHIMERA).

Note that CRPAs constitute one methodology of multi-element antenna techniques against jamming and spoofing. Flexible and configurable testing, such as M3 Systems is highly adept in, will be needed to explore such additional technologies.

CRPAs’ Exciting Future

Developing GNSS receiver architectures will present more—and more advanced—integration between the antenna and the receiver. As this trend develops, CRPA antennas will gain further capability and intelligence to meet the demands of more exacting applications. Such high-requirement applications will drive the need for PNT component and sensor integration, as other positioning technologies augment and complement the GNSS receiver and antenna. This gives rise to further RFI challenges within the multi-varied PNT component device.

Overall, this forms a compelling case for miniaturization of all components, and the need for system-on -chip (SoC) innovations.

Needless to say, every innovation, every addition of a new component or integration structure must be thoroughly tested, in simulation first, and then in the field. Proper simulation is essential to identify weaknesses, prevent system failure and ensure continuous operations. As jamming and spoofing methods increase in sophistication, so too must test of countermeasures such as CRPAs. The factors involved in advanced counter-interference techniques are very complex, and their testing present many challenges. 

Thoroughgoing experience as well as highly developed, highly proven technology is a must. M3 Systems supplies them all.

As CRPA techniques develop and advance, they will explore three possible implementation forms, depending on the receiver layer, advantages and limitations:

• RF layer CRPA-GNSS: To the best of our knowledge, all current CRPA-GNSS product consist of this format (Figure 3).

• Pre-correlation layer CRPA-GNSS (Figure 4).

• Post-correlation layer CRPA-GNSS (Figure 5).

The next-generation CRPA-GNSS will be based on innovative mixed implementations of these techniques, and simulation of these new products must continually evolve to match their sophistication.

CRPA Simulation and Testing

M3 Systems employs a systemic layer approach in GNSS simulation. This makes it possible to generate observables at intermediate levels, such as raw data and IQ baseband. As a result, the test performance verification is simplified.

There are several important key performance indicators (KPIs) and topics to assess before undertaking CRPA testing:

• Characterization of individual antenna elements

• Phase alignment: it is required that test bench is phase aligned (below 5ps at minimum & phase-sharing architecture) to keep the CRPA unit under test able to reject undesired signal

• Anechoic chamber limitations: The time of validity is limited to tens of minutes. CRPA simulation in a controlled environment offers many advantages compared to over-the-air (OTA) testing with an anechoic chamber. With OTA testing, the scenario duration, time and date are limited by the fixed positioning of transmit antennas; angular fidelity is acceptable for a few tens of minutes.

The key parameters for a testing campaign with CRPAs include:

• the power and carrier-phase calibration of the system

• the number of frequencies and constellations to be tested 

• signal fidelity and spectrum purity

• sensor fusion.

The main challenges for CRPA testing encompass:

• Which KPI should predominate in simulation, according to the product and its intended application. For example, extent of coverage or signal fidelity? A system layer approach such as M3’s is mandatory here.

• Record and playback testing must consider the power dynamic and how to address it, as the jammer and the receiver will likely have a very high power difference. Multiple RF stages are necessary. 

• In hybrid testing, with the injection of synthesized signal phenomena on 4 antenna channels instead of one (for a 4-antenna CRPA), the necessary phase coherence and synchronization must be accounted for.

Conclusion

Because CRPAs can adapt dynamically to interfering signals, they offer a very effective anti-jamming and anti-spoofing solution. They form a crucial element for the future of GNSS. CRPA in the civil market is both achievable and practical. Product research and development is ongoing and very exciting, but it requires many means of experienced, qualified, multi-element and multi-method testing and simulation to realize CRPA’s potential improved capabilities. M3 Systems has the specialized expertise and knowledge to fill this role.

For more information visit, M3 Systems.

The post CRPA for GNSS: Benefits, Challenges and Testing appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

This year, CAST Navigation celebrates its 40th anniversary of delivering powerful GNSS/inertial simulation systems to a range of clients across military and commercial PNT sectors, helping them make the decisions necessary to refine and improve their products and processes. This has been the company’s sole focus throughout its history: developing customized perfection in the single area of GNSS simulation. 

The company started in 1981 and from the outset employed engineers with experience in both inertial technology and GPS receiver design. Founders Dick Gibson, a legendary GPS pioneer and educator, George Gutheim and John Clark, Sr. quickly established a reputation for thought leadership and powerfully accurate testing tools. From an early focus on aviation, they expanded to produce embedded GPS/INS (EGI) integration tools, diagnostic tools and support equipment, controlled reception pattern antenna (CRPA) testing and more.

Over the years, CAST has built a long list of faithful clients, working with them to develop custom software and hardware. CAST’s strong R&D initiatives have produced many unique software and hardware innovations, from helping military clients land UAVs on moving aircraft carriers to testing GNSS systems in commercial land vehicles and aircraft.

MODULAR DESIGN

CAST has regularly delivered some very large systems, custom tailored for its clients’ product development labs. They are modularly designed so that clients can pick and choose the options they need, “similar to a Lego set,” says VP John Clark, Jr. with a smile.

An early milestone in company history was the development of a software simulation program for Kalman filter designers, called NavSim. The Australian Air Force approached CAST, looking for a way to simulate in their labs. CAST modified NavSim for their needs; that was the very first CAST simulator. To do so, the company adapted a satellite chassis simulator by Stanford Telecommunications, a pioneering company in the industry, founded by people largely responsible for the design of GPS signals. 

“We came to an agreement,” recalls Clark. “We used their generator. They built an interface into it so CAST could send digital data and produce RF signals. It was two racks, three feet high, a dynamic GPS simulator that did 5 channels.”

“CAST wrote all the software to generate the pseudoranges and supplied it to the 7200’s hardware. It produced L-band signals from that. CAST was the first commercial company to produce that software.”

After the company integrated the STeL generators for a period of time, it contracted with Rockwell, who had built a signal generator card that could be put into a PC and generated a complete 10-satellite GPS set of data. “We had them custom-design a control board, to enable CAST to properly drive their signal generator card and control the power levels of each satellite.”

Lou Pelosi, another VP with 25 years of experience at CAST, picks up the story from there. “We used those cards for a number of years. In 2005 we developed our own signal gen card that is FPGA-based. It’s CAST-designed, CAST-manufactured.”

“One of the lessons we learned with Rockwell cards: we can do more than one trajectory at a time, we can simulate trajectories of more than one vehicle. We’ve also learned how to do multiple vehicle IMUs based on those same lessons. It taught us how to build our software and our systems in a modular fashion. We can now drive multiple vehicles with phased array multiple element antennas. We could never do this today without learning those lessons from the past.”

“We now manufacture our own inertial interface card. We can drive almost everybody’s IMU using our own card.”

JAMMING AND SPOOFING

The company naturally focuses on both GPS jamming and spoofing, meeting the urgent needs of its customers. Its systems can drive multiple IMUs and EGIs. “We also have the capability to connect multiple systems together, to drive a whole fleet of navigators. That’s a pretty big deal.”

CAST systems are very stable, requiring minimum calibration and minimum warmup time. 

Increasingly, customers need specific jamming waveforms to fulfill their needs. CAST has the ability to deliver larger systems to drive multiple navigators, with each navigator using a CRPA antenna, and each output from each of its EGI systems coherent to one another.

THE FUTURE

The trend they see and are actively pioneering is the production of bigger systems, capable of driving multiple IMUs and multiple CRPAs simultaneously. The custom, modular approach is necessary for customer requirements in highly complicated laboratories. CAST hands over a system that is both highly developed yet able to be further customized within the customer’s own lab.

“There’s a lot of stuff they don’t tell us. These guys are developing next-gen fighters and bombers, both manned and unmanned,” says Clark.

“We can customize our interfaces to whatever anybody decides to build into their box,” he concludes. “We build our own IMU and GNSS cards, we have full control, they’re all built on FPGA.”

“We’ve learned to be flexible under different conditions and difficult conditions.”

The post Four Decades of Close, Customized Client Collaboration: The CAST Tradition appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.