GPS World

Category: Timing

  • It’s Galileo time: Options for crystal oscillators in OSNMA-enabled receivers

    It’s Galileo time: Options for crystal oscillators in OSNMA-enabled receivers

    By Francesco Ardizzon, Nicola Laurenti, Carlo Sarto and Giovanni Gamba

    To ensure the authenticity of the Galileo navigation messages, the Open Service navigation message authentication (OSNMA) mechanism requires a loose synchronization between the receiver clock and the system time.

    To ensure the authenticity and the integrity of the transmitted messages, the Timed Efficient Stream Loss-tolerant Authentication (TESLA) protocol for broadcast authentication requires a loose time synchronization between the transmitter and the receiver — that is, an upper bound to the time offset between their clocks. In the context of the TESLA-based Open Service navigation message authentication (OSNMA) protocol, it is customary to assume that:

    • On the system side, the transmission is synchronous because the satellites are equipped with high-precision atomic clocks, the drift of which is assumed negligible with respect to those at the receiver side.
    • At the receiver side, commercial clocks can be found that are less accurate and less stable, which accounts for the substantial time mismatch between the transmitter and the receiver clocks accumulating over time.

    To limit the impact of such mismatch on OSNMA operation, it is envisioned that clocks for authenticated tachographs onboard vehicles, such as the ones that will be employed for the position authenticated tachograph for OSNMA launch (PATROL) project, are reset and precisely realigned to system time in periodic workshop visits. However, the clock mismatch must satisfy the OSNMA constraint at all times between successive workshop resets, in the “holdover” period, and through all possible operating conditions, to ensure constant authenticity of the navigation message.

    In other contexts, this task is performed by such means as network synchronization protocols.

    However, we are considering a scenario where, during holdover, we cannot rely on other sources, such as an internet connection or other devices to synchronize with the reference time to assure the authenticity of our time reference and, consequently, of the PVT solution. We also cannot trust any signal received during the holdover period, thus we should not use the PVT solution to synchronize the clock.

    Here, we have two goals. First, investigate the causes of the misalignment and frequency deviation in clock generators commonly found on the market for GNSS receivers. Second, relate the clock specification parameters, taken directly from the real-time clock (RTC) device datasheets, the holdover period, and the OSNMA misalignment constraints.

    Atomic clocks at ESTEC’s Navigation Laboratory in The Netherlands independently validate Galileo timing performance. (Photo: ESA)
    Atomic clocks at ESTEC’s Navigation Laboratory in The Netherlands independently validate Galileo timing performance. (Photo: ESA)

    Frequency Accuracy and Stability

    Two metrics are usually employed to evaluate the performance of an oscillator.

    • Clock frequency accuracy is the normalized difference between the frequency output and its nominal value, f0.
    • Clock frequency stability is the normalized instantaneous frequency deviation from its local mean.

    Although devices are characterized in terms of their stability, we are interested in measuring their accuracy y(t)ΔF(t)⁄f0, where ΔF(t) is the instantaneous frequency deviation from f0 at time t. The calibration performed during each workshop reset brings the residual misalignment to a negligible value called phase calibration error. On the other hand, we will later discuss the residual frequency deviation, due to the frequency calibration error.

    The loose time synchronization requirement TL states that the authenticity of the navigation message received at time t is guaranteed if |ΔT(t)|≤TL, at every t during the holdover period.

    Finally, we can relate accuracy and misalignment using the bound

    Equation 1  (1)

    which allows us to upper bound the clock misalignment at any time t in terms of the frequency accuracy along the whole interval elapsed from the last calibration time t0.

    Accuracy Loss for Receiver Clocks

    Thanks to their affordable price and wide temperature operating conditions, quartz crystal oscillators are used for clock generation in GNSS receivers (see TABLE 1). We distinguish among simple, temperature-controlled crystal oscillators (TCXOs) and oven-controlled crystal oscillators (OCXOs). GNSS receivers typically employ TXCOs because they offer the best trade-off in terms of power consumption, price and typical accuracy.

    Table 1. Summary of the main quartz crystal oscillator characteristics.
    Table 1. Summary of the main quartz crystal oscillator characteristics.

    Sources of Frequency Accuracy Loss. Quartz crystals are piezoelectric materials, therefore any additional stresses and environmental changes generate an additional voltage, decreasing the clock stability. In the automotive scenario, the main sources of accuracy loss are temperature changes, long-term aging, and the residual calibration frequency offset, while the impact of accelerations, vibrations, gravity variation and supply voltage oscillation can safely be neglected as they result in changes of a few parts per billion.

    Currently, no analytic relationship is known between frequency accuracy and temperature for TCXOs (or OCXOs). Therefore, as reported in datasheets, the inaccuracy induced by the temperature changes is bounded by a constant value Ytemp across the whole operating temperature range. This yields a bound on the clock misalignment that increases linearly with the time from the last calibration.

    Long-term aging has significant impacts on the clock frequency accuracy and may affect the device even when it is not used for a long time (see Figure 1). A critical aspect of this effect is that it is time-variant, with the accuracy loss increasing over time.

    Figure 1. Graphical representation of the model for aging accuracy loss: upper-bound (red) versus estimated model (blue). (Image: R. Filler and J. Vig)
    Figure 1. Graphical representation of the model for aging accuracy loss: upper-bound (red) versus estimated model (blue). (Image: R. Filler and J. Vig)

    However, datasheets typically report a single value, Yage (Tdata ), which bounds the accuracy at a fixed time Tdata.  

    The effect of long-term aging for both TCXOs and OCXOs was investigated in a 1993 study by R. Filler and J. Vig measuring the accuracies of oscillator models for several years. The study concluded that a logarithmic fit is better suited for long-term measurements, while a linear fit is better suited for initial measurements (t<30 days) and is a loose upper-bound for longer times. Because we are interested in establishing a prudential upper bound rather than a precise estimate, we use the constant upper bound Yage (Tdata) for all t<Tdata and a linear upper bound for t>Tdata. This leads to a linearly increasing bound on the time offset before Tdata, and a quadratically increasing bound after Tdata.

    Finally, the misalignment due to the frequency calibration error accumulates over time. An off-the-shelf oscillator has an initial accuracy that depends on the frequency tolerance ftol. To improve this, a precise calibration is performed, trying to synchronize the RTC with the nominal frequency f0, such as by using PTP. The contribution to the accuracy loss given by calibration can be bounded by Ycalib, a value set a priori either by system design or during the calibration process itself, yielding again a linearly increasing bound on the clock misalignment.

    Bound on the Total Misalignment. In general, the cross-correlation between the uncertainties is unknown; we can only consider the worst-case scenario where the total uncertainty is bounded by the sum of the single bounds. This choice represents a prudential and conservative approach that may yield a rather loose bound with very high probability.

    Thus, considering that all terms in the clock error bound increase over time, we can bound the total misalignment as

    Equation 2    (2)

    Example Values from Datasheet Specifications

    Based on the above result, we can deem a commercial oscillator suitable for OSNMA operation if B(TR )≤TL. We can then compare the requirements for different RTCs, focusing on TCXOs designed for GNSS receivers suitable for the automotive scenario, with f0=52 MHz and a target operating temperature range between –20° Celsius and +85° Celsius. We assume that devices are subject to a calibration process, such that YcalibYtemp; thus we have neglected the calibration accuracy loss. We report in Table 2 the values of the misalignment bound, B(TR ), for TR=2 years and the maximum reset period TR,max such that B(TR,max)≤TL, with a loose time synchronization requirement TL=165s, as computed form the specs found in the datasheets. 

    Table 2. Bound values <i>B</i>(<i>T<sub>R</sub></i>) and <i>T<sub>R</sub></i><sub>,</sub><i><sub>max</sub></i> computed using several RTCs’ datasheet specs with <i>T<sub>L</sub></i>=165 s and <i>T<sub>R</sub></i>=2 years.
    Table 2. Bound values B(TR) and TR,max computed using several RTCs’ datasheet specs with TL=165 s and TR=2 years.

    Conclusions

    To ensure the authenticity of the GNSS navigation message, the Galileo OSNMA protocol requires a loose synchronization between the transmitter and the receiver. The misalignment between transmitter and receiver clock needs to be lower than a threshold TL for the whole holdover period TR. In this article, we have investigated the causes of the misalignment and frequency deviation in clock generators commonly found on the market and defined a general relationship between TL ,TR and the specifications commonly found in datasheets. Finally, we examined several mass-market temperature-controlled crystal oscillator datasheets, evaluating their performance in terms of worst-case offset bound B(TR).

    The bound represents a prudential conservative approach and may be rather loose. However, given the lack of a consistent statistical model, this is a reasonable solution. We conclude that most devices can satisfy the constraint B(TR)≤TL=165 s with a workshop reset period of TR = 2 years.

    Acknowledgements

    This study was conceived within the PATROL (Position Authenticated Tachograph foR OSNMA Launch) project, funded by the EU Agency for the Space Programme through the Fundamental Elements programme, under procurement No. GSA/OP/23/16 “Development, supply and testing of a Galileo open service authentication user terminal (OSNMA) for the GSA.”

    The authors acknowledge the invaluable support provided by the PATROL technical team: Davide Marcantonio (Qascom), Fabio Pisoni, Giovanni Gogliettino and Domenico di Grazia (ST Microelectronics), Alexandre Allien and Francois Riou (FDC), Jacques Kunegel (ACTIA), Simón Cancela Díaz and Belén Villanueva Coello (GMV).

    PATROL success was fostered by the commitment and support of Flavio Sbardellati (EUSPA Project Officer), Gonzalo Seco Granados and Alexander Rügamer (EUSPA external reviewers), Javier Simon (EUSPA reviewer), Ignacio Fernandez-Hernandez and Giovanni Vecchione (EC reviewers). The authors thank colleagues Giada Giorgi (UNIPD) and Lorenzo Dal Corso (Qascom) for reviewing this work.

    The content of this publication does not reflect the official opinion of the European Union or of the EU Agency for the Space Programme. Responsibility for the information and views expressed therein lies entirely with the authors.

    Francesco Ardizzon is a Ph.D. student and Nicola Laurenti an associate professor in the Department of Information Engineering of the University of Padova, Italy. Carlo Sarto is the head of the security engineering division and Giovanni Gamba the head of the SIGINT and EW division at Qascom S.r.l., in Bassano del Grappa, Italy.

     

    REFERENCES

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    I. Fernandez-Hernandez, T. Walter, A. Neish, and C. O’Driscoll, “Independent time synchronization for resilient GNSS receivers,” in 2020 International Technical Meeting of The Institute of Navigation, 02 2020, pp. 964–978.

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    PATROL, https://www.patrol-osnma.eu/, last access 11 2021.

    “IEEE standard definitions of physical quantities for fundamental frequency and time metrology—random instabilities,” IEEE Std 1139-2008, pp. c1–35, 2009.

    J. Vig, “Quartz crystal resonators and oscillators for frequency control and timing applications – a tutorial,” in IEEE International Frequency Control Symposium Tutorials, 2016.

    M. Lombardi, “Fundamentals of time and frequency,” in The Mechatronics Handbook, CRC Press, 01 2002, ch. 17.

    J. Cartright, “Aging performance on crystals,” http://www.conwin.com/pdfs/aging perf crystals.pdf, 2008.

    R. Filler and J. Vig, “Long-term aging of oscillators,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 40, no. 4, pp. 387–394, 1993.

    W. Riley and D. Howe, Handbook of Frequency and Stability Analysis. Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, 2008-07-01 00:07:00 2008.

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  • Right on time: Protecting critical infrastructure against threats

    Right on time: Protecting critical infrastructure against threats

    Managing live sky and terrestrial time sources to protect critical infrastructure against cybersecurity threats

    By Greg Wolff, Microchip Technology

    Critical public infrastructure systems that rely on GNSS for reception of positioning, navigation and timing (PNT) data have been identified by national security agencies across the globe as potential cybersecurity attack vectors. Late in 2020, the U.S. Department of Homeland Security (DHS) published the “Resilient PNT Conformance Framework” guidelines, providing a common reference point to help critical infrastructures become more resilient to PNT attack threats. Within the framework, a cybersecurity approach has been proposed.

    Prevent. In this first layer of defense, threats are prevented from entering a system. However, it must be assumed that it is not possible to stop all threats.

    Respond. Atypical errors or anomalies are detected and action taken, such as mitigation, containment and reporting. The system should ensure an adequate response to externally induced, atypical errors before recovery is needed.

    Recover. The last line of defense is returning to a proper working state and defined performance.

    Figure 1. The four levels of resilience defined in the DHS “Resilient PNT Conformance Framework” guidelines. (Image: Microchip)
    Figure 1. The four levels of resilience defined in the DHS “Resilient PNT Conformance Framework” guidelines. (Image: Microchip)

    Four Levels of Resilience

    Based on the Prevent-Respond-Recover cybersecurity model, the PNT Conformance Framework document describes four levels of resilience. Note that the resilience levels build upon each other — Level 2 includes all enumerated behaviors in Level 1, and so forth.

    The framework provides a clear set of PNT resilience guidelines for equipment, whether at the silicon, module or system level. Although the framework is not specific to the use of GNSS, much of the focus has centered on GNSS vulnerabilities and the ability to be resilient to GNSS outages, whether caused by unintentional disruptions or intentional threats. However, the GNSS resiliency of specific equipment or technology does not fully address the needs of critical infrastructure operators who are managing the use of PNT services over large geographical areas.

    Critical Infrastructure Expansion

    Critical infrastructure is typically constructed in a tiered manner, beginning with a set of core sites connected to secondary sites that are ultimately connected to remote sites. With the rollout of 5G networks, densification and massive deployment of wireless access points will improve coverage and enable higher bandwidths to support the internet of things (IoT) and related services. However, this massive scale of access points will also require accurate timing at a much larger number of endpoints.

    Within the power utility infrastructure, the power grid is being augmented and expanded with alternative energy sources, such as solar and wind. The modernized smart grid is a highly distributed architecture that is dependent on accurate timing for coordination, monitoring and logging of data for operation and identification of power-outage fault detection. Additionally, power utilities rely on timing services for communications and transport of telemetry data throughout their entire operations.

    To date, GNSS has been the go-to source for timing, creating an exponential increase in the dependency on GNSS. Because of this massive dependency, the impact of errors or interruptions today is more significant than ever before.

    Figure 2. Example view of timing network at data centers across the globe. (Image: Microchip)
    Figure 2. Example view of timing network at data centers across the globe. (Image: Microchip)

    Terrestrial Time Distribution

    As an alternative for delivering accurate time to large numbers of locations and reducing dependency on GNSS, critical infrastructure operators are turning to the use of terrestrial distribution using packet protocols so that high accuracy distribution can be achieved using Precision Time Protocol (PTP).

    The virtual Primary Reference Time Clock (vPRTC) is a highly secure and resilient network-based timing architecture developed to meet the expanding needs of modern critical infrastructures. The vPRTC is simple in concept. It blends proven timing technologies into a centralized and protected source location, and then uses commercial fiber-optic network links and advanced IEEE 1588 PTP boundary clocks to distribute 100-ns PRTC timing where it is needed in end points that might be hundreds of kilometers away.

    Just as a GNSS-satellite-based timing system distributes timing to end points using open-air transmission, the vPRTC distributes timing using a terrestrial (typically fiber) network. The difference is that the operator remains 100% in control of the network and can secure it as necessary. This network-based timing is referred to as trusted time. It can be distributed as the primary source of timing or it can be deployed as a backup to GNSS timing solutions.

    Even with the many reliability and security benefits of the vPRTC approach, however, sole dependency on terrestrial time can become a single point of failure, just like a strategy dependent solely on GNSS. Because of this, critical infrastructure operators are deploying architectures that use both GNSS and terrestrial time. To do this effectively, operators find themselves with the need to have centralized management and visibility of both key sources of time. Further, to deliver on the promise of timing resiliency, a unified management system needs to include capabilities that can deliver a cybersecurity solution encompassing the Prevent-Respond-Recover DHS security guidelines across all nodes of the timing network.

    Figure 3. A measurement of phase difference between GNSS time and terrestrial time. (Image: Microchip)
    Figure 3. A measurement of phase difference between GNSS time and terrestrial time. (Image: Microchip)

    Unified Time Management

    Having a bird’s eye view of all nodes of a timing network is essential for providing timing security and resiliency. In the case of a GNSS anomaly or terrestrial time instability, when a problem occurs the most immediate need is to quickly identify whether the event is isolated to a specific location, affects a region, or in some cases is caused by a global situation. A centralized management and monitoring system provides a green, yellow and red threat-status indication representing different locations of interest. It is a simple way for operators to know the overall health of their timing infrastructure.

    When problems surface, critical infrastructure operators next need visibility of “observables” that can quickly isolate the root cause. With today’s timing networks relying on both GNSS time and terrestrial time, the ability to see observables that represent both timing sources in a unified manner is critical.

    GNSS Observables

    Multipath interference, weather anomalies, jamming and spoofing are terms commonly used when referring to GNSS vulnerabilities. Gaining insights (visibility) into the details to identify the root cause, however, requires more specific characterization of the signal.

    Visibility into the quality of GNSS reception is accomplished by monitoring GNSS observables. Table 1 provides a sample of key GNSS observables that can be tracked and monitored.

    Table 1. Sample of key terrestrial time GNSS observables.
    Table 1. Sample of key terrestrial time GNSS observables.

    Terrestrial Time Observables

    Characterizing the quality of terrestrial time requires time measurements between equipment interconnections within a single location (intra-office) or across nodes of a network (inter-office) — for example, comparison of equipment inputs and outputs or comparison of signals at different sites.

    Additionally, with the standardized use of PTP, the ability to evaluate network timing packet metrics is needed to verify time transfer from location to location. Terrestrial time performance calls for a different set of observables to be made visible and monitored. Table 2 provides a sample of key terrestrial time observables.

    When managing a large geographical area, being able to measure the phase difference between GNSS time and terrestrial time at multiple locations simultaneously enables an operator to determine how well these two sources of time compare. As described previously, critical infrastructure operators are ultimately in need of resiliency, which can best be achieved using both time sources.

    Measuring the two sources against each other at multiple locations creates the highest level of trust knowing that these independent time sources are well aligned.

    Table 2. Key terrestrial time observables that must be made visible and monitored.
    Table 2. Key terrestrial time observables that must be made visible and monitored.

    Conclusion

    With cooperation from industry, standards organizations and government organizations such as DHS, the use of timing services has become recognized as a foundational technology for critical infrastructure operations. Leveraging industry-standard cybersecurity models will help strengthen and harden timing equipment.

    Although equipment resiliency is vital, having a bird’s eye view of timing performance across the entire network is the starting point for providing complete network visibility that is critical to providing timing security and resiliency. To deliver on the promise of timing resiliency across critical infrastructure, operators need a unified management system that enables simple and complete visibility of both GNSS and terrestrial time observables.

    With a unified management of these two timing sources, operators have a platform to apply Prevent-Respond-Recover to timing threats and achieve the highest levels of resiliency and cybersecurity protection.

    Greg Wolff is senior product line manager of Frequency & Time Systems at Microchip Technology. He has worked in the time and frequency industry since 1988 and was an early pioneer in the marketing of network synchronization solutions to major critical infrastructure operators across the globe. He is an active contributor to emerging standards supporting PNT resiliency and most recently, as part of Microchip Technology’s Frequency and Time Systems group, launched the BlueSky GNSS Firewall. He holds a degree in engineering science from California Polytechnic State University – San Luis Obispo.

    Image: gremlin/E+/Getty Images
    Image: gremlin/E+/Getty Images
  • ADVA boosts PNT resilience with new software release

    ADVA boosts PNT resilience with new software release

    Photo: ADVA
    Photo: ADVA

    Upgraded range of synchronization solutions now includes enhanced PNT resiliency against jamming and spoofing attacks and cyberthreats

    ADVA has announced a new software release of its core and edge timing technology, to provide higher levels of positioning, navigation and timing (PNT) security and resilience to synchronization networks. The new release follows the Resilient PNT Conformance Framework issued by the U.S. Department of Homeland Security (DHS).

    The upgraded series of PTP grandmaster clock solutions now enables operators to automatically harness public key infrastructure. Along with enhanced certificate management, this delivers more robust security and removes complexity, the company said.

    ADVA’s core and mid-sized PTP grandmaster devices now also integrate enhanced aPNT+ technology, providing advanced jamming and spoofing detection as well as mitigation with automatic switchover in the event of cyberattacks.

    The software replaces costly hardware devices previously used for PNT protection and achieves enhanced DHS Level 4 Resiliency in PNT self-survivability, the highest in the industry. The new software release also supports 100 Mbit/s over fiber for interconnectivity with optical timing channels from third-party vendors as well as support for PTP profiles for a wide range of industries.

    “Today’s timing networks require greater accuracy than ever before. But mission-critical national networks need improved resilience and security as defined by the latest standards. With our trusted PNT assurance solutions, we’re providing the GNSS protection and cybersecurity that today’s operators need to meet current and future challenges,” said Gil Biran, GM of Oscilloquartz, ADVA. “From phase synchronization in critical national infrastructure to traceable timestamping in financial networks, highly precise and protected timing is key to successful operations. This upgrade sets a new standard for secure synchronization and delivers it to more networks than ever before.”

    The new 11.1.1 software release features upgrades to ADVA’s comprehensive range of Oscilloquartz edge timing products, the OSA 5412/22 series, as well as its core synchronization devices, the OSA 5430/40 series. The solutions now provide multi-layered security for synchronization infrastructure through improved certification management and PKI.

    As part of ADVA’s intelligent and scalable assured PNT platform, the ADVA aPNT+, the solutions also feature innovation for detection of spoofing and jamming as well as countermeasures to prevent service disruption. With PTP capabilities for new verticals, including the PTP broadcast profiles (SMPTE ST-2059-2/AES67), the new release will bring precise, reliable synchronization to many new customers.

    Further information is available in these slides.

  • Orolia and Hoptroff partner on traceable timing to protect networks

    Orolia and Hoptroff partner on traceable timing to protect networks

    Hoptroff’s Traceable Time as a Service to become an option for Orolia’s product portfolio; webinar scheduled for Dec. 15

    Orolia and timing solutions provider Hoptroff are partnering to deliver a service combining Orolia’s resilient positioning, navigation and timing (PNT) solutions with Hoptroff’s timing synchronization software.

    The collaboration will offer Hoptroff’s Traceable Time as a Service (TTaaS) as an add-on to Orolia’s suite of products, providing precise and verifiable time to customers in enterprise, financial, telecom, utilities, public safety, and other markets where traceable time is critical.

    Webinar scheduled

    Orolia and Hoptroff will host a joint webinar to discuss the partnership and new resiliency options for customers on Dec. 15 at 12 p.m. EST. Register here.

    Hoptroff’s TTaaS offers an additional level of security and precision to meet stringent regulatory and resilient infrastructure requirements by delivering accurate time over the network using a VPN connection over broadband or fiber networks.

    The bundled solution will simplify the challenge of getting accurate, traceable time in applications where GNSS access is not available or dependable. It can also serve as an accurate, reliable backup to GNSS to provide a high level of resiliency to timing systems being used in critical infrastructure.

    “As industries evolve and computer applications become more complex and widely distributed, it is essential that devices in a distributed process share the same accurate timescale to reconstruct digital events after the fact,” said Tim Richards, COO at Hoptroff. “Network-based traceable timing, such as TTaaS, provides resilient backup to a GNSS installation in the case of signal disruption, monitors the quality of performance of time servers, and keeps a record of this timing quality at a location of the customer’s choice. Our partnership with Orolia means businesses will now be able to back up and monitor physical time servers and virtual servers in the cloud, so that they can be sure they share the same accurate timescale, and they have the records to prove it.”

    “The partnership with Hoptroff aligns with Orolia’s resilient PNT strategy by providing a wireline solution to augment its space-based PNT solutions. This allows us to further simplify the challenge customers face when building a highly resilient timing solution,” said Jeremy Onyan, Orolia’s director of time sensitive networks. “By combining Orolia’s anti-jamming and anti-spoofing solutions, high-performance GNSS-based timing products, alternative signals like STL, a local high-quality oscillator, and now a wireline-based TTaaS we have one of the most robust portfolios of resilient PNT solutions in the market. Additionally, with the recent acquisition of Seven Solutions, we are well positioned to extend our capabilities into high-accuracy time distribution.”

    Seven Solutions is a global innovator in White Rabbit sub-nanosecond time transfer and synchronization technology. “With the capability to distribute time with little to no accuracy loss, Orolia’s customers using Hoptroff’s TTaaS or other time references such as GNSS can extend that time to other parts of their networks and create a high level of resiliency against potential outages,” Onyan added.

    Image: Panuwat Sikham/iStock/Getty Images Plus/Getty Images
    Image: Panuwat Sikham/iStock/Getty Images Plus/Getty Images
  • RadioWaves launches GPS/GNSS timing antennas

    RadioWaves launches GPS/GNSS timing antennas

    Photo: RadioWaves
    The GP-L1-32-T-MNT GPS timing antenna with mount included, RHCP polarized, 1.571 to 1.61 GHz. (Photo: RadioWaves)

    RadioWaves, an Infinite Electronics brand and a manufacturer of high-quality microwave antennas and accessories, has released a new series of GPS/GNSS timing antennas that cover L1 and L5 GPS bands.

    The new series of GPS/GNSS timing antennas provide axial ratio and higher accuracy for the reception of satellite timing signals and reference frequencies for enhanced phase synchronization in precision network deployments.

    The high gain, low noise figure of 2 dB and high out-of-band rejection provided by these antennas allows for the use of longer and cost-effective cables for easy and flexible installs. They also feature a VSWR less than 1.8:1 and are compatible with several existing mounting brackets. In addition, thee fully ruggedized, weather-sealed antennas are IP67 compliant for use in outdoor and marine environments.

    The antennas come equipped with built-in surge protection and support a wide range of GNSS including GPS, GLONASS, BeiDou and Galileo, as well as Iridium. Increased position accuracy in densely populated urban areas, flexible installation, and improved system security make RadioWaves’ latest antenna offering a valuable system component, the company said.

    Models include

    • GP-L1-L5-40-N, an L1+L5 GPS timing antenna, 1.166 to 1.218 GHz and 1.559 to 1.606 GHz
    • GP-L1-32-T, a L1 GPS timing antenna, RHCP polarized, 1.574 to 1.61 GHz
    • GP-L1-32-T-MNT, an L1 GPS timing antenna with mount included, RHCP Polarized, 1.571 to 1.61 GHz.
  • ADVA offers embedded timing for third-party hardware

    ADVA offers embedded timing for third-party hardware

    ADVA has introduced its OSA 5400 SyncModule embedded timing solution, designed to enable technology suppliers to integrate precise synchronization into their hardware. Its M.2 form factor can add crucial timing capabilities to switches, routers, open compute servers and other IT devices.

    The OSA 5400 SyncModule provides GNSS, precision time protocol (PTP) and network time protocol (NTP) engines as well as comprehensive PTP and GNSS monitoring and assurance functionality. According to ADVA, the module can enable assured sub-microsecond timing in public and private networks as well as critical infrastructure.

    “Our OSA 5400 SyncModule brings something completely new and very valuable to the market,” said Gil Biran, general manager, Oscilloquartz, ADVA. “For the first time, third-party technology manufacturers will be able to embed the most advanced synchronization capabilities into their designs and easily control them with our Ensemble Sync Director or their own management system.”

    Featuring multiple interface options for easy integration, the OSA 5400 SyncModule comes with an open API. It can also be managed by ADVA’s proven Ensemble Sync Director management system.

    Image: ADVA
    Image: ADVA
  • Chronos Technology now owned by its employees

    Chronos Technology now owned by its employees

    Vit_Mar/iStock/Getty Images Plus/Getty Images
    Vit_Mar/iStock/Getty Images Plus/Getty Images

    Chronos Technology Ltd., a UK-based resilient synchronization and timing company, has transitioned to employee ownership through the Chronos Technology Employee Ownership Trust (EOT) Ltd.

    Charles Curry who established Chronos Technology in September 1986 and was co-owner alongside his wife, Angela Curry, had been deliberating succession planning and their exit from the business. Various options such as a third-party sale or a management buyout were considered but quickly dismissed.

    “I am aware of business owners who had exited through third-party sales and had not enjoyed the experience of working under new management for the agreed handover period,” Curry said. “New owners generally change the dynamic of the business, often introducing new staff and work practice without giving opportunity to existing staff and process, and we did not want this for Chronos.”

    “Over the years we have established a work ethic that puts the customer first,” Curry continued. “The EOT protects the loyal Chronos family and ensures the customer-facing continuity of the business and, most importantly, safeguards jobs. Going forward, in the hands of the employees, the company will benefit from increased customer engagement and the commitment to a team approach to steer the business on the next phase of its journey.”

    Chronos Technology specializes in resilient synchronization and timing systems, smart technologies, GNSS and cybersecurity solutions for critical national infrastructure, with industry experience gathered over 35 years in specialist technologies such as GNSS, PTP, NTP and SyncE.

    The company provides GPS coverage solutions in hangars, manufacturing areas and underground, as well as smart technology solutions and GNSS jamming detection and location solutions for law enforcement. Customers include telecom, finance, energy, data centers, broadcast, aerospace, defence and security, enterprise/IT, emergency services, transport and manufacturing.

  • Sandia Labs shows GPS-free quantum-based wayfinding device

    Sandia Labs shows GPS-free quantum-based wayfinding device

    Sandia National Laboratories scientist Peter Schwindt, left, and postdoctoral scientist Bethany Little examine the vacuum package held in a yellow, 3D-printed mount. (Photo: Bret Latter/Sandia) 
    Sandia National Laboratories scientist Peter Schwindt, left, and postdoctoral scientist Bethany Little examine the vacuum package held in a yellow, 3D-printed mount. (Photo: Bret Latter/Sandia)

    The compact, fieldable device could provide means to navigating without GPS

    News from Sandia National Laboratory

    Don’t let the titanium metal walls or the sapphire windows fool you. It’s what’s on the inside of this small, curious device that could someday kick off a new era of navigation.

    For more than a year, the avocado-sized vacuum chamber has contained a cloud of atoms at the right conditions for precise navigational measurements. It is the first device that is small, energy-efficient and reliable enough to potentially move quantum sensors — sensors that use quantum mechanics to outperform conventional technologies — from the lab into commercial use, said Sandia National Laboratories scientist Peter Schwindt.

    Sandia developed the chamber as a core technology for future navigation systems that don’t rely on GPS satellites, he said. It was described earlier this year in the journal AVS Quantum Science.

    Countless devices around the world use GPS for wayfinding. It’s possible because atomic clocks, which are known for extremely accurate timekeeping, hold the network of satellites perfectly in sync.

    But GPS signals can be jammed or spoofed, potentially disabling navigation systems on commercial and military vehicles alike, Schwindt said.

    Instead of relying on satellites, Schwindt said future vehicles might keep track of their own position. They could do that with onboard devices as accurate as atomic clocks, but that measure acceleration and rotation by shining lasers into small clouds of rubidium gas like the one Sandia has contained.

    Atomic accelerometers and gyroscopes already exist, but they’re too bulky and power-hungry to use in an airplane’s navigation system. That’s because they need a large vacuum system to work, one that needs thousands of volts of electricity.

    A compact device designed and built at Sandia National Laboratories could become a pivotal component of next-generation navigation systems. (Photo: Bret Latter/Sandia)
    A compact device designed and built at Sandia National Laboratories could become a pivotal component of next-generation navigation systems. (Photo: Bret Latter/Sandia)

    “Quantum sensors are a growing field, and there are lots of applications you can demonstrate in the lab,” said Sandia postdoctoral scientist Bethany Little, who is contributing to the research. “But when you move it into the real world, there are lots of problems you have to solve. Two are making the sensor compact and rugged. The physics takes place all in a cubic centimeter (0.06 cubic inches) of volume, so anything larger than that is wasted space.”

    Little said her team has shown that quantum sensing can work without a high-powered vacuum system. This shrinks the package to a practical size without sacrificing reliability.

    Instead of a powered vacuum pump, which whisks away molecules that leak in and wreck measurements, a pair of devices called getters use chemical reactions to bind intruders. The getters are each about the size of a pencil eraser so they can be tucked inside two narrow tubes sticking out of the titanium package. They also work without a power source.

    To further keep out contaminants, Schwindt partnered with Sandia materials scientists to build the chamber out of titanium and sapphire. These materials are especially good at blocking out gasses like helium, which can squeeze through stainless steel and Pyrex glass. Funding was provided by Sandia’s Laboratory Directed Research and Development program.

    Construction took sophisticated fabrication techniques that Sandia has honed to bond advanced materials for nuclear weapons components. And like a nuclear weapon, the titanium chamber must work reliably for years.

    The Sandia team is continuing to monitor the device. Their goal is to keep it sealed and operational for five years, an important milestone toward showing the technology is ready to be fielded. In the meantime, they’re exploring ways to streamline manufacturing.

    Sandia National Laboratories is a multimission laboratory operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration. Sandia Labs has major research and development responsibilities in nuclear deterrence, global security, defense, energy technologies and economic competitiveness, with main facilities in Albuquerque, New Mexico, and Livermore, California.

  • Orolia to acquire Seven Solutions for resilient PNT

    Orolia to acquire Seven Solutions for resilient PNT

    Photo:

    Merger to deliver high-end performance and ultra-accurate timing and frequency products for commercial, critical infrastructure and defense markets worldwide

    Orolia has entered into a definitive agreement to acquire Seven Solutions, a global innovator in White Rabbit sub-nanosecond time transfer and synchronization technology. This transaction is subject to customary closing conditions and approvals required by the Spanish government and is expected to close before the end of the year.

    This is Orolia’s 11th acquisition in the past seven years.  

    The merger with Seven Solutions, based in Granada, will enhance Orolia’s portfolio for defense, aerospace, data centers, telecom, financial services, smart grids and other critical infrastructure industries, and will enable the next-generation applications dependent on ultra-precise, resilient timing and frequency technology.

    GPS World published an article about Seven Solutions and its White Rabbit technology in its October issue.

    “Orolia and Seven Solutions under one umbrella will combine our world-leading technologies to draw a new frontier in network timing to sub-nanosecond levels, delivering the most robust and accurate resilient PNT solutions for our customers,” said Orolia CEO Jean-Yves Courtois. “Seven Solutions’ long history of delivering cutting-edge time distribution solutions to sectors like telecommunications, smart grids, aerospace, defense and scientific facilities aligns perfectly with Orolia’s DNA.”

    Orolia and Seven Solutions will integrate global sales, marketing, product development and operations.

    Orolia’s full-scale, modular approach to resilient PNT includes atomic clocks with a combination of GNSS signals protected with interference detection and mitigation technology, together with low-Earth-orbit secure alternative signals. The addition of Seven Solutions’ products will deliver terrestrial sub-nanosecond time distribution from distant and potentially redundant locations.

    “We believe the union of our companies will produce the future of time transfer and frequency distribution solutions in terms of accuracy, reliability and interoperability,” said Rafael Rodriguez, chief technology officer and co-founder of Seven Solutions. “Finance, 5G telecommunications, data centers and hyperscalers have new and upgraded functionalities requiring ultra-accurate time distribution accuracy. To maximize interoperability, our solution for time transfer is based on the White Rabbit concept that has been pushed over the last decade to become the basis of the standard high accuracy time transfer profile (within the recent release of IEEE 1588 of precision time protocol).”

    Orolia and Seven Solutions are members of the Open PNT Industry Alliance. The international organization focuses on market concepts that strengthen economic and national security by supporting government efforts to implement resilient PNT capabilities for critical infrastructure.

  • US Coast Guard Nav Center warns of GPS rollover concern

    US Coast Guard Nav Center warns of GPS rollover concern

    Image: Infadel/ iStock/Getty Images Plus/Getty Images
    Image: Infadel/
    iStock/Getty Images Plus/Getty Images

    The U.S. Coast Guard has issued a statement on a possible GPS software bug that could send systems back to 2002.

    The potential vulnerability may cause an event of the “GPS Week Number Rollover” type to occur within systems utilizing Network Timing Protocol Daemon (NTPD) and GPS Daemon (GPSD) software.

    On Oct. 24, a bug in older versions of the software may trigger the system date to roll back to sometime in March 2002. All systems running the most recent software update, version 3.23.1 (released Sept. 21) should be unaffected.

    While this is not a problem with GPS, this has the potential to cause significant impact, the Coast Guard stated. All networks operating are encouraged to verify that they are using the most recent version (3.23.1) and report any problems to the Navigation Center watch by phone 703-313-5900 or by email at [email protected].

  • ViaLite supports Raytheon with mission critical, extended length GPS over fiber

    ViaLite supports Raytheon with mission critical, extended length GPS over fiber

    ViaLite GPS Link: Blue OEM module and rack chassis card hardware formats shown. (Photos: ViaLite)
    ViaLite GPS Link: Blue OEM module and rack chassis card hardware formats shown. (Photos: ViaLite)

    ViaLite is supplying Raytheon Technologies with its GPS over Fiber Extension Kit for Microchip GPS servers. The kit provides mission-critical GPS timing and synchronization for systems requiring extremely accurate clock signals.

    Standard transmission distances for the extension kit can be up to 10 km, while solutions are available for distances as long as 50 km.

    “The ViaLite kit was chosen for its unique performance with Microsemi’s S650 timing server, along with our best-in-class quality, reliability and support,” said Craig Somach, ViaLite director of Sales North America.

    The ViaLite GPS link is designed to provide a remote GPS/GNSS signal or derived timing reference to equipment located where no signal is available, such as inside buildings or tunnels. By using optical fiber instead of traditional coaxial cable, extreme distances are possible with no radio frequency loss and zero introduction of noise.

  • RNT Foundation proposes attributes for resilient timing RFP

    RNT Foundation proposes attributes for resilient timing RFP

    Image: RNT Foundation
    A National Resilient Timing Architecture should include delivery by fiber and RF along with space-based, according to the RNT Foundation. (Image: RNT Foundation)

    The Resilient Navigation and Timing (RNT) Foundation has published a white paper proposing attributes for a government Request for Proposal (RFP) to acquire timing services.

    “A National Resilient Timing Architecture – Now for an RFP!” builds upon the foundation’s October 2020 white paper “A Resilient National Timing Architecture.”

    Timing services, most of which are now sourced directly or indirectly from GPS, are essential for myriads of network, transportation, financial, industrial, and other applications. The National Timing Resilience and Security Act of 2018 (NTRSA) requires establishment of one or more systems to serve as alternatives and back up GPS timing.

    The RNT Foundation’s October 2020 white paper discusses how a national timing architecture fulfilling the requirements of NTRSA could be established relatively easily and inexpensively. It proposes that, rather than building its own system, the government contract for services with commercial providers.

    The new white paper outlines some of the requirements and evaluation criteria the government might use when acquiring timing services.

    Goals

    The paper postulates that the goal of such a procurement should be to establish a federal timing “backbone.” This would fulfill the requirements of NTRSA, which recognizes that timing is critical for many applications and is also the basis for most electronic positioning and navigation systems.

    Establishing this backbone will provide users with an alternative and a safety net for GPS disruptions, and at other times enable more resilient and reliable services. As a backbone, it would provide basic, foundational services upon which others would be able to build. The new services would be expected to:

    • support a wide variety of public and private applications across the nation
    • be entirely independent from and have minimal or no common failure modes with GPS and other GNSS
    • provide multiple and diverse methods of timing delivery
    • serve both fixed and mobile users.

    Regarding this last point, the paper notes that mobile devices must know their location before they can make use of timing signals. Thus, the selected system or combination of systems also will have to provide GPS-independent location information at a basic level to mobile users.

    Requirements

    Successful proposals, the paper envisions, will need to meet a number of requirements including

    • serving the entire U.S. land area, airspace, and coastal waters to about 200 miles offshore
    • enabling all fixed and mobile users to access at least one non-space-based source (to ensure no common failure modes with GPS/ GNSS)
    • timing accuracy in all locations to within 500 nanoseconds of universal coordinated time (UTC); this accuracy should be within 100 nanoseconds of UTC for the 50 largest metropolitan areas
    • one or more integrity measures to provide users confidence in system(s) accuracy
    • a very high rate of continuity and availability, similar to that of navigation beacons for aircraft
    • a performance monitoring and control system.

    Evaluation Criteria

    Fortunately for the government, numerous systems and companies are already able to provide the needed services. Deciding which to select will likely be a significant effort. Some of the evaluation criteria suggested by the RNT Foundation white paper are:

    Annual Cost – While cost will not be the only consideration in this acquisition, the government always has a responsibility to taxpayers to weigh it as an important factor.

    Infrastructure Required Per Unit of Coverage Area – This has been cited by the Department of Transportation as a very important consideration. Not only does the amount of infrastructure affect cost, but it also has implications for environmental and community impacts.

    Spectrum – Signal disruption by in-band and out-of-band transmissions has been a significant issue for GPS. New PNT wireless and radio-frequency services should pose as few spectrum concerns as possible. Spectrum band reservations, licenses, pre-allocated bands, other bands and adjacent band uses will all be given consideration.

    Penetration – While the government may not list this as a requirement, the ability of a service to reach underwater, underground and indoor locations will likely be desirable and part of proposal evaluation.

    Resilience – The vulnerability of GPS signals to disruption will undoubtedly make the resilience of potential backup and complementary systems a major issue. The RNT Foundation paper discusses two kinds of resilience – operational and recovery.

    Operational resilience is defined as “the ability of a system, combination of systems, or service to resist disruption (e.g.: jamming, spoofing, physical damage negatively impacting service).” One measure of resilience might be the energy needed to disrupt signals.

    Recovery resilience is described as “The speed and ease with which a service can return to normal operation” after a disruption.

    Cybersecurity – Similarly, cybersecurity is seen as having two components. The first is network security, defined as the degree to which systems are isolated from or connected to networks. Second is signal security, and is how well signals can be protected from infiltration and imitation.

    Endorsements for GPS Alternative Timing

    Since the “National Resilient Timing Architecture” white paper was issued in 2020, calls for GPS alternatives have intensified, and the white paper itself has received an important endorsement.

    On May 7, the telecommunications industry standards group Alliance for Telecommunications Industry Solutions (ATIS) vigorously supported federal funding for GPS alternatives. In letters to leaders in both houses of Congress, ATIS cited “the urgent need for funding the deployment and adoption of Alternative Positioning, Navigation, and Timing (PNT) Systems in U.S. critical infrastructure, including the U.S. telecom industry.”

    The need for federal support for timing and positioning backups for GPS was also supported by a two-year old study released by RAND Corporation in May. While the paper went to great lengths to argue against a duplicate GPS-like capability (something no one has supported to the best of our knowledge), it quietly suggested federal support for both a national timing system and location services to serve E-911 systems.

    Numerous recent media releases from U.S. Space Force have revealed serious military threats to GPS and other space-based systems. A variety of killer-satellites, lasers and other weapons have turned space from a sanctuary into a potential battle ground. While not specifically calling for alternatives to GPS, the Space Force announcements have made it clear the nation needs to “get the bullseye off GPS.” Establishing at least one terrestrial alternative system similar to those operated by our adversaries will make U.S. satellites and signals much less attractive targets, according to Greg Winfree, former assistant secretary at the U.S. Department of Transportation.

    Federal Funding Needed

    Federal funding for improving national timing was specifically supported by a group of CEOs and senior executives from major telecom companies. Acting as the National Security Telecommunications Advisory Committee (NSTAC), the group’s May report to President Biden discussed GPS vulnerabilities and threats, and urged establishment of a capability

    “…similar to that reflected in the Resilient Navigation and Timing Foundation’s paper entitled A Resilient National Timing Architecture. Further, to enhance the ability of commercial entities to afford leveraging this architecture, the Administration should appropriate sufficient funds to lay the foundation for creating this timing architecture, with the Federal Government being the first customer for what will ultimately become a resilient, interconnected network for PNT delivery.”

    Federal funding support is necessary, according to NSTAC, because free GPS services greatly suppress market demand for alternatives.

    Dana Goward is president of the Resilient Navigation and Timing (RNT) Foundation.