A new data source to help scientists better understand the ionosphere and its potential impact on communications and positioning, navigation and timing (PNT) is now available to the public.
The data, which was collected by sensors on GPS satellites in 2018, was released through a collaborative effort by Los Alamos National Laboratory and the National Oceanic and Atmospheric Administration (NOAA).
“Radio signals from satellite or ground-based transmitters can travel through the ionosphere or bounce off of it, so ionospheric conditions have the potential to disrupt communications depending on the density of electrons,” said Erin Lay, a remote-sensing scientist at Los Alamos who was a technical lead on the project. “This new set of data will help us better model and predict the behavior of the ionosphere and possibly improve the reliability of our communications and positioning, navigation, and timing services, which are critical for both everyday life and national security.”
The ionosphere is the boundary between Earth’s atmosphere and space, stretching 40 to 250 miles above Earth’s surface. It is composed of tenuous atmosphere and charged particles (ions and electrons) that interact with traversing radio waves. The behavior of the ionosphere reacts to weather on Earth, such as thunderstorms, wind, and hurricanes, as well as space weather created by solar winds impacting Earth’s magnetic field.
“NOAA’s Space Weather Prediction Center (SWPC) serves a huge customer base interested in space weather effects on communications and GPS-reliant technologies,” said Bill Murtagh, program coordinator at SWPC. “We expect access to these Los Alamos data sets to improve the development, validation, and testing of models used at SWPC for characterizing and forecasting ionospheric disturbances.”
Preview graphic. (Image: NOAA)
The new data comes from unique measurements of lightning events, each of which produces a flash of radio waves that gets dispersed through the ionosphere before it is detected on satellite receivers. Each measured flash provides a snapshot of the ionospheric conditions at that instant, and many lightning measurements accumulated over time provide a unique view of ionospheric weather. This is the first-ever global set of ionospheric electron density data to use a naturally occurring source phenomena.
Before this release, the data available to feed ionosphere models was primarily from arrays of ground-based receivers, which are limited because they only monitor fixed locations. According to Lay, “the new data is gathered from lightning that happens all over the world and will give scientists the opportunity to study the ionosphere in ways previously not possible.”
The release of underutilized data sets was a priority established in the 2019 National Space Weather Strategy and Action Plan. Los Alamos processed the data from its radio-frequency sensors that are onboard GPS satellites and used for nuclear treaty monitoring, and then worked with a government interagency group, called the Space Weather Operations, Research and Mitigation (SWORM), to facilitate public release.
NOAA’s National Centers for Environmental Information will host the data on existing sites that serve terrestrial weather and space weather resources.
The ionosphere is shown in purple and not-to-scale in this image. (Image: NASA’s Goddard Space Flight Center/Duberstein)
U‑blox has launched its new GNSS evaluation software, u-center 2. The software, which runs on Microsoft Windows, offers anyone working with 10th-generation (M10) u‑blox GNSS technology a highly intuitive interface to configure GNSS products, evaluate their performance, improve the quality of their software, and experience the performance boost achieved using GNSS-related services.
U-center 2 is the successor to the u-center GNSS evaluation software, which has been used by design engineers for almost two decades to develop GNSS receiver applications. Compatible with u‑blox M10 GNSS technology, u-center 2 is designed to offer improved performance over its predecessor, as well as new features that simplify configuration, evaluation and software development of GNSS-based solutions.
Screenshot: U-blox
U-center 2 provides personalized workspaces with adaptive window elements offering a choice of views to observe static and dynamic behavior of the connected GNSS receiver. The built-in log player, which accepts log files from the previous version of the software, features easy message- and time-based navigation and lets users set the playback speed, making development of end products more efficient. Automatic updates ensure that the software includes the latest features with minimal user effort.
U-center 2 simplifies the evaluation of GNSS-related location services such as AssistNow, through which GNSS receivers gain access to GNSS aiding data, enhancing startup performance, and saving power.
Predecessor u‑center will continue to be the go-to solution for GNSS solutions based on earlier technology platforms.
“We are confident that users will immediately recognize how easy u-center 2 makes it to set up and evaluate the latest generations of our GNSS chips and modules,” said Bernd Heidtmann, product manager, Product Strategy for Standard Precision GNSS, u‑blox. “With its fresh and minimalist user interface, the upcoming quick product configuration designed for key use cases, and optimized data logging, u-center 2 will raise the benchmark for GNSS evaluation tools in terms of performance and user experience.”
RedTail Lidar Systems has delivered six lidar systems to the 707th Ordnance Company stationed at Joint Base Lewis-McChord. The systems will provide explosive ordnance disposal (EOD) technicians an opportunity to assess how lidar can be used to enhance their operations.
The RedTail Lidar Systems RTL-450 was integrated onto the Teledyne FLIR SkyRaider unmanned aerial system (UAS) to address a broad range of the EOD community’s 3D mapping needs. Captain William R. Hartman, the commander of the 707th EOD Company, stated that the highlight of the testing was using the lidar system to map terrain.
The RTL-450 also can be used to calculate crater volumes from improvised explosive device (IED) blasts, perform route planning for unmanned ground vehicles, aid in mission planning, and conduct surveillance. The 3D point clouds generated allow operating areas to be viewed from any perspective using the rotation and zoom capabilities provided within the viewer software.
The underlying lidar technology used in the RTL-450 was licensed from the Army Research Laboratory (ARL). The micro-electromechanical (MEMS) mirror-based design provides enhanced 3D imagery suitable for applications where artificial intelligence and machine learning (AI/ML) algorithms can be used for target detection and classification, because of the high point density of the point clouds.
The system can operate in either a raster scan mode for surveillance missions or a side-to-side line scan mode for area mapping while the UAS is flying. The intuitive command and control, high brightness display integrated into the ground control station (GCS), and real-time 3D map generation allows operators to begin mission planning and analysis even before the mapping or surveillance missions are completed.
“Delivering these six lidar systems to EOD technicians for test and evaluation is a significant step forward in using MEMS mirror-based lidar technology to address a broad range of Department of Defense 3D mapping needs,” said said Brad DeRoos, president and CEO of RedTail Lidar Systems. In addition, this delivery represents a true success story in transitioning a technology out of a Department of Defense laboratory and back into the hands of military operators.”
On Sept. 16, the National Geodetic Survey (NGS) released the latest beta version of OPUS, called Beta OPUS Projects 5.0. This version of OPUS now accepts real-time kinematic data and post-processed GNSS vectors from vendor software. See the box titled “Beta OPUS Projects 5.0 Webpage” on the website.
As stated in the announcement, NGS has developed a file format for submitted real-time kinematic (RTK) data and post-processed GNSS vectors from vendor software to NGS. It is denoted as GNSS Vector Exchange Format (GVX). This format enables NGS to incorporate the data into its GNSS processing routines.
This is similar to the original Receiver Independent Exchange Format (RINEX) developed for making post-processing more efficient when combining GNSS data from manufacturers outputting raw GPS data in varying file formats. In my opinion, this is a significant improvement to NGS’s OPUS web utility.
Users can obtain background information about the GVX file format by clicking the link GVX file format. More detailed information about the GVX format can be obtained by clicking on the Documentation link.
Basically, GVX is a standardized format for exchanging GNSS vectors derived from GNSS survey data using any manufacturer hardware and software results (see the box titled “Excerpt from Documentation of GVX”). NGS designed the format so that it included all of the necessary data (including metadata) of a GNSS vector for incorporation into a survey network for performing a least-squares adjustment.
To this end, this document proposes a new standardized file format known as the GNSS Vector Exchange Format (GVX). GVX aims to provide a standard format for exchanging GNSS vectors derived from varying GNSS survey methods and manufacturer hardware. The file format includes all of the necessary data of a GNSS vector for inclusion in a survey network for least squares adjustment, as well as metadata which describes the vector. The format is meant for any type of GNSS vector, whether it was derived in real-time or from baseline post-processing. GVX has been written in extensible markup language (XML). XML was chosen because it was designed to carry and store data in plain text format, it is easy to expand and/or upgrade to new operating systems, and it can be read by both humans and machines.
A sample GVX file can be obtained by clicking on the link titled “Example of GVX file, project day 066, day 052, day 053, day 054.” As NGS states in the documentation, the output can be read both by humans and machines. What’s important is that it can be read by machines so the information can be incorporated into software programs. GNSS vendors have all the information they need to generate the output file to enable users to import the data into OPUS Project 5.0. Users will have to contact their software providers to determine whether their software routines generate the GVX output files.
As I previously mentioned, this new option in OPUS Projects 5.0 is a significant improvement because many surveyors use RTK networks to obtain coordinates of marks. It will also facilitate the occupation of benchmarks with GNSS equipment to support the NGS 2022 Transformation tool. North Carolina, my home state, has a real-time network (RTN) that includes 96 GNSS CORS. (See the box titled “NC GNSS CORS and Real-Time Network.”) Currently, the North Carolina GNSS CORS and RTN has 4584 RTN service subscriptions.
I could not find a current list of public RTK networks in the United States, but I did locate a Jan. 7, 2014, GPS World article by Eric Gakstatter that provided a list of public RTK base stations in the country. It’s not up-to-date, but it highlights that, more than seven years ago, more than half of the U.S. states had some kind of public RTK network. I would like to update the table, so I’d appreciate receiving information on the status of any public RTK network. Please feel free to send me an email at [email protected].
California Real Time Network (CRTN) (single baseline). Plate Boundary Observatory. Single baseline.
Colorado
Mesa County (Trimble network) and Plate Boundary Observatory (single baseline).
Florida
Florida Department of Transportation. Leica network.
Idaho
Plate Boundary Observatory (single baseline).
Indiana
Indiana Department of Transportation. Leica network.
Iowa
Iowa Department of Transportation. Leica network.
Kentucky
Kentucky Transportation Cabinet. Trimble network.
Louisiana
Louisiana State University. Trimble network.
Maine
Maine Department of Transportation. Trimble network.
Massachusetts
Massachusetts Department of Transportation. Leica network.
Michigan
Michigan Department of Transportation. Leica network.
Minnesota
Department of Transportation. Trimble network.
Mississippi
University of Southern Mississippi. Trimble network.
Missouri
Missouri Department of Transportation. Trimble network.
Montana
Plate Boundary Observatory (single baseline).
Nevada
Washoe County. Trimble network. Las Vegas Valley Water District. Leica network. Plate Boundary Observatory (single baseline).
New Mexico
Plate Boundary Observatory (single baseline).
New York
New York Department of Transportation. Leica network.
North Carolina
N.C. Department of Environment and Natural Resources. Trimble network. $500 one-time sign-up fee.
Ohio
Ohio Department of Transportation. Trimble network.
Oregon
Oregon Department of Transportation. Leica network. Plate Boundary Observatory (single baseline).
South Carolina
South Carolina Geodetic Survey. Public but charges a usage fee. Trimble network.
Tennessee
Tennessee Department of Transportation. Public but charges a usage fee. Topcon network.
Texas
Texas Department of Transportation. Public but only available to TxDOT employees and TxDOT contractors. Trimble network.
Utah
Utah Automated Geographic Reference Center. Public but charges a usage fee. Trimble network. Plate Boundary Observatory (single baseline).
Vermont
Vermont Geodetic Survey. Trimble network.
Washington
Washington State Reference Network (Seattle Public Utilities). Trimble network. Public but charges a usage fee. Pierce County (Leica Network). Plate Boundary Observatory (single baseline).
West Virginia
West Virginia Department of Transportation. Trimble network.
Wisconsin
Wisconsin Department of Transportation. Trimble network.
Wyoming
Plate Boundary Observatory (single baseline).
Why do I believe that this new option in OPUS Projects 5.0 is so important? Because it facilitates the incorporation of accurate GNSS-derived ellipsoid and orthometric heights into the National Spatial Reference System (NSRS). With the development of improved algorithms, the results of coordinates computed using GNSS CORS/RTNs are more accurate today than ever before. During the last decade, there have been many studies analyzing GNSS data to estimate the accuracy values of coordinates from RTN data.
A study titled “Accuracy of GNSS Observations from Three Real-Time Networks in Maryland, USA” by Daniel Gillins, Jacob Heck, Galen Scott, Kevin Jordan and Ryan Hippenstiel presented at FIG Working Week 2019 in Hanoi, Vietnam, April 22–26, 2019, provided a comparative evaluation on the accuracy of three independent RTNs constructed with differing hardware and software. Their study was based on 486, 5-minute duration GPS + GLONASS network RTK (NRTK) observations. The results indicated that repeat NRTK vectors could be combined to meet 1 cm horizontally and 2 cm vertically (ellipsoid height) accuracies at 95%. confidence. See the box below. It should be noted that the repeat observations should be observed at different times of the day (for instance, separated by > 2–3 hours), as well as, in my opinion, if possible at least more than two different days.
A total of 486, 5-min duration, GPS+GLONASS NRTK observations were collected on nine bench marks distributed over a 4,000 square km area with rovers connected to three different RTNs in Maryland. Each RTN was developed with equipment and software from a different manufacturer, yet all three RTNs performed similarly in terms of accuracy. When differenced with coordinates from a static GNSS survey campaign, the horizontal and vertical RMSE of the NRTK-derived coordinates was 2.3 cm horizontally and 4.5 cm vertically at 95% confidence. Repetitive NRTK vectors on each baseline differed between ± 2.4 cm horizontally and ± 3.4 cm vertically at 95% confidence. As a final accuracy evaluation, hybrid survey networks consisting of repeat NRTK vectors and baseline solutions from post-processing static GPS data collected at RTN base stations and CORSs were adjusted by least squares. Prior to adjustment, the VCV matrices of the vectors were scaled by variance-component estimation. Adjustment of hybrid survey networks with four repeat NRTK vectors per bench mark produced network accuracies at 95% confidence for the adjusted coordinates at all bench marks less than 1 cm horizontally and 2 cm vertically (ellipsoid height).In addition to the benefits of using efficient and accurate NRTK vectors, the hybrid survey network approach makes use of redundant vectors for checking data and avoiding blunders. The approach also provides traceability because the NRTK vectors are tied to an RTN base station which is tied to CORS. Finally, these networks ensure the survey is referenced to the published coordinates of the CORSs which are held as constraints in the adjustment.
Lastly, I would like to remind users that only three months remain until the December 31, 2021, cutoff to submit GPS on Benchmarks data that NGS can guarantee will be analyzed to compute the initial set of 2020.0 Reference Epoch Coordinates (RECs) that will be released with the Modernized NSRS. This initial set of RECs is currently the only set that NGS can guarantee will be used to build the 2022 Transformation Tool. Once the transformation model is finalized, the NAVD 88 – NAPGD 2022 transformation values will be locked in and will not be updated as additional sets of RECs are computed. If you have questions or concerns about this cut-off date, please contact your NGS Regional Geodetic Advisor, or drop NGS a line at [email protected].
Beta OPUS Project 5.0 is a web-based tool that makes it easier to submit data to NGS. I would encourage NSRS users to occupy as many benchmarks with GNSS equipment and submit the data to NGS before the Dec. 31 deadline. Not only will these data help in improving the transformation model, but the marks will be included in the first computation of Reference Epoch Coordinates (RECs). You can obtain information about Reference Epoch Coordinates in NGS’s NOAA Technical Report NOS NGS 67 publication titled “Blueprint for the Modernized NSRS, Part 3: Working in the Modernized NSRS.” A future column will address the different types of coordinates that will be distributed by NGS with the modernized NSRS.
A roundup of recent products in the GNSS and inertial positioning industry from the October 2021 issue of GPS World magazine.
MOBILE
Smartwatch
Provides dual-frequency and topo maps
Photo: Coros
The Vertix 2 GPS “adventure watch” is equipped with a dual-frequency GNSS chipset for high accuracy. It communicates with all global navigation satellite systems simultaneously, and has a battery life of 140 hours while using GPS — otherwise, the battery extends to 60 days. Global offline maps include landscape, topography and hybrid views. The watch includes an Insta360 action camera and has 32 GB of internal storage.
AirFinder helps companies locate, monitor and manage business assets indoors and outdoors. The quickly deployable, massively scalable platform does not require an IT infrastructure or extra components or hardware. Rather than using an internal Wi-Fi system, AirFinder operates on Link Labs’ patented and secure Symphony Link network. Location data from each AirFinder device securely flows to the AirFinder web app or directly to customer databases via extensible APIs, which enable users to monitor assets in real time, analyze asset history, add rules and alerts, establish geofences and more.
The EdgeSync network timing platform provides NTP and PTP grandmaster and boundary clock functionality for real-time edge applications. High performance, scalability, ease of use and manageability make EdgeSync suitable for data centers, finance, mobile edge computing, enterprise, smart grid, industrial IoT, process control and telecommunications. EdgeSync uses a multi-GNSS receiver (GPS, Galileo, GLONASS, BeiDou and QZSS), PTP and Synchronous Ethernet (SyncE) as input references and generates PTP, SyncE, NTP and timing signals (10 MHz, 1 PPS and time-of-day message) as outputs. It features dual 1-GbE ports for both copper RJ45 and optical network timing connections. EdgeSync also can provide IEEE 1588-2008 (PTP) grandmaster and boundary clock functionality.
CompassOne provides real-time military-grade location, orientation and direction sensing for deployed static and on-the-go assets. It receives all GNSS, ensuring uninterrupted operation. The device can be used both in counter UAV operations and general situations requiring satellite navigation. With a strong focus on durability and ruggedness, CompassOne is suitable for installation and operation in harsh environments. Military-grade connectors and high-end stainless-steel hardware ensure uninterrupted connection and protection from the elements, while the aluminum underside provides exceptional impact resistance and rigidity while keeping overall weight low. CompassOne can operate alone or be integrated with DroneShield’s DroneSentry system.
The Snapdragon 888+ 5G mobile platform is expected to power commercial smartphones from ASUS, Honor, Motorola, vivo and Xiaomi in the second half of this year. Satellite systems supported include all four constellations (GPS, BeiDou, Galileo, GLONASS) with dual-frequency GNSS. Additional systems supported include NavIC, QZSS and SBAS. Snapdragon 888+ provides AI-enhanced gameplay, streaming, photography and premium connectivity. Compared to its predecessor (the 888), Snapdragon 888+ provides an increased Qualcomm Kryo 680 CPU Prime core clock speed at up to 3.0 GHz and the sixth-generation Qualcomm AI engine with up to 32 TOPS AI performance, an improvement of more than 20%.
The Skydel Real-Time Performance graphs illustrate the software-defined engine’s low latency during a GNSS simulation. (Screenshot: Orolia)
A new real-time performance capability, now standard on all Skydel-powered GNSS simulators, achieves an ultra-low latency of 5 milliseconds. Skydel’s software-defined architecture is designed to meet the demanding GNSS simulation testing requirements in the automotive, military, space and other high-tech industries. Skydel also supports hardware-in-the-loop simulations without sacrificing ultra-low latency and high-end performance. A dashboard shows real-time performance graphs and enables users to grade the simulator’s performance, interpret data, diagnose inefficiencies, and optimize scenarios on the fly. As the system reaches its limits, it remains stable and fully operational, preserving the integrity of the simulation.
PointMan software is now integrated into the Vivax Metrotech vLoc3 with a GNSS real-time kinematic (RTK) receiver to create a utility-locate device. Using the RTK-Pro internal cellular module with 4G LTE capabilities, the operator can connect to the NTRIP RTK caster that provides RTCM 3 corrections. With the integration of PointMan with the vLoc3 RTK-Pro, critical buried infrastructure can be captured, recorded and displayed at survey-grade accuracy without additional external equipment or post-processing. The integration provides centimeter accuracy of the precise location of buried utilities in real time. Data collected includes the type of utility, the depth of cover and the utility’s precise location.
Geospatial and location intelligence for smart cities
Screenshot: Hexagon Geospatial
M.App Enterprise 2021 is a significant update to the platform for creating geospatial and location intelligence applications. The latest release features new browser-based 3D capabilities and enhanced visual effects, plus the ability to create and configure custom applications more easily. It allows users to access LuciadRIA’s 3D features with support for panoramic imagery, shading, ambient occlusion and other visualization effects to build browser-based solutions. It also features a new browser app configurator that makes it easier to create spatio-temporal dashboards, or Smart M.Apps. Feature Analyzer now allows users to add and manage multiple datasets on the fly and set up workflows.
Hexagon | NovAtel has updated its GPS Anti-Jam Technology (GAJT) portfolio with the new GAJT-710 product line, which features several enhancements over the previous generation.
The GAJT-710 product line is the next evolution of NovAtel’s battle-proven anti-jam technology for land and marine platforms. The new jammer direction-finding capability of GAJT enables situational awareness and a new silent mode feature reduces its thermal signature. These improvements, including enhanced GNSS tracking performance, are achieved while maintaining the same form and fit of the previous generation product.
GAJT units are deployed worldwide, providing anti-jam protection on land, at sea and in the air. Across these environments, GAJT protects GNSS navigation and precise timing receivers from the growing threats of intentional jamming and unintentional interference. GAJT reliably provides APNT for allied forces no matter the scenario.
“NovAtel has proven itself as a leader for assured PNT through our GAJT portfolio,” said Steve Duncombe, executive vice president of aerospace and defense at Hexagon’s Autonomy & Positioning division. “The new GAJT-710 builds on that success by providing new features combined with existing mission-proven technology to continue providing evolutionary APNT capabilities for the warfighter, national infrastructure and other mission-critical applications.”
NovAtel’s commitment to APNT is central to its product design approach. Deep GNSS expertise and lean manufacturing capabilities enable the delivery of high-performance products like the GAJT-710 in large volumes with minimal production and delivery times, the company said.
The GAJT-710 product line is available for land vehicles, marine vessels, positioning networks and timing infrastructure.
Facebook has open-sourced the design of its time card, which features the ultra-precise u‑blox ZED-F9T timing module, providing easy access to nanosecond-level timing
Photo: u-blox
Facebook has chosen the u‑bloxZED-F9T GNSS receiver module for timekeeping, according to u-blox. By improving the synchronization of networked computers, Facebook’s time card can significantly speed up the performance of its data centers and distributed databases.
By open-sourcing their designs, Facebook has bolstered the adoption of highly accurate timing solutions based on u‑blox technology. These solutions can be adopted by other industries requiring nanosecond-level timing, such as 5G cellular networks or smart power grids.
Facebook set out to create a precise timing solution that reduces the computational overhead required when synchronizing the timing between different computers in a network, u-blox said. The social media company used a u‑blox ZED-F9T multi-band GNSS receiver to sync up its solution with the highly accurate GNSS atomic clocks. To bridge possible gaps in GNSS coverage and keep clock drift to a minimum, the time card contains a backup timing source: a miniaturized atomic clock continuously synchronized with GNSS time.
To maximize the impact of the solution, Facebook decided to open-source the design of its time card, which fits onto a PCIe form factor. Anyone with experience working with microelectronics can turn any PC built on an x86 architecture and featuring a network interface controller into a nanosecond-level-accurate timing and synchronization solution, u-blox said.
Easy access to nanosecond-level timing accuracy — based on the u‑blox RCB-F9T timing board, which hosts the u‑blox ZED-F9T GNSS receiver — opens new avenues in industry segments that rely on highly synchronized signals, such as 5G network base stations that require tighter synchronization than those of previous generations, u-blox said.
As power-distribution networks become more complex to accommodate a growing share of decentralized renewable energy, they are becoming more reliant on reliable and accurate timing solutions. Data centers and computer networks will be able to modernize infrastructure management to speed up performance and reduce latencies.
Facebook has shared the GitHub repository including the specs, the schematics, the mechanics, the bill of material, and the source code in partnership with the Open Compute Project (OCP) under the Time Appliance Project (TAP).
The Automotive News PACEpilot award recognizes post-pilot, pre-commercial innovations in the automotive and future mobility space. These represent product, software/IT system or process and idea incubators that have the potential to revolutionize an automaker’s business.
This was the second year Automotive News recognized PACEpilot honorees and the first time the publication named Innovations to Watch. Swift’s precise positioning platform was selected as one of 10 winners from a group of 23 finalists from 20 companies.
Swift’s precise positioning solution consists of the receiver-agnostic Starling positioning engine and cloud-based corrections from Skylark precise positioning service. The system was designed for autonomy and built to scale for automotive, to change how automakers and OEMs navigate by reducing costs, improving product flexibility, improving safety and delivering high-fidelity, lane-level absolute positioning.
Swift’s technology has been developed into a precise positioning platform that can improve vehicle GNSS-based positioning from an average of 3 meters of accuracy to better than 4 centimeters. Swift’s solution is a software-only implementation with minimal impact to hardware on the vehicle. The accuracy can be guaranteed down to less than one failure per 1,142 years of driving, making it a highly reliable ADAS and automated driving sensor.
“The team at Swift is honored to receive this recognition from Automotive News,” said Joel Gibson, executive vice president of Automotive at Swift Navigation. “Swift is bringing its ground-breaking, high-accuracy localization to the automotive space and we appreciate that those in the industry are taking notice.”
Company responds to calls for stronger national resilience against GNSS vulnerabilities and cyber threats to PNT services
Photo: ADVA
ADVA has responded to calls from the U.S. Department of Homeland Security (DHS) and the National Institute of Standards and Technology (NIST) to protect critical infrastructure from the growing danger of GNSS vulnerabilities and cyber threats to positioning, navigation and timing (PNT) services with the launch of its aPNT+ platform.
The scalable aPNT+ platform meets all the latest guidelines for resilient PNT, the company said. It provides end-to-end control and timing network visibility for robust protection against the catastrophic risks that PNT disruption poses to national security and essential assets such as power grids.
“Cyber threats are at an all-time high. At the same time, the infrastructure that our economies and lives depend on has never been more reliant on weak and highly vulnerable satellite signals. That’s why the U.S .DHS and NIST are driving for PNT services to be more resilient and for network operators to implement strategies to counteract the vulnerabilities of GPS and other GNSS systems, including in-network PTP timing feeds. Our trusted aPNT+ platform is the definitive response,” the company said.
Governments worldwide have issued guidelines to protect businesses and society from disruption to PNT services, including US Executive Order 13905, which was followed by the DHS Resilient PNT Conformance Framework and NIST Cybersecurity Framework for PNT Profile. The government guidelines urge operators to swiftly implement technologies and measures to safeguard vital infrastructure.
Based on these guidelines, ADVA integrated an intelligent and scalable aPNT platform into its product portfolio. Even without GPS or GNSS timing, the solution provides an intelligent, end-to-end self-recovery system designed around a three-fold framework. Integrating sophisticated multi-layer detection, multi-source backup and multi-level fault-tolerant mitigation, it delivers high levels of resilience, robustness and cybersecurity. It integrates the DHS framework’s four levels of PNT resilience while also providing enhanced level-four resilience, the highest level for trusted PNT services assurance.
“For industries and governments, timing is now a critical service in need of urgent protection,” said Gil Biran, general manager, Oscilloquartz, ADVA. “Being open and scalable, it offers an end-to-end range of cost-effective solutions… for augmented resilience, robustness and cybersecurity.”
Technology evaluation capabilities inaugurated in demonstration for U.S. Department of Homeland Seurity
NextNav and Satelles Inc. have partnered on an alternative positioning, navigation and timing (PNT) testbed in the San Francisco Bay area.
Designed and managed by NextNav with a timing source from Satelles, the testbed creates scenarios and conditions to rigorously test the precision and resilience of alternative PNT solutions, allowing technologies to be evaluated in the absence of signals from GPS and other GNSS.
NextNav used the testbed to demonstrate the precision and resilience of the company’s TerraPoiNT network in a GPS-denied environment using STL from Satelles as its absolute timing source. This demonstration for the U.S. Department of Homeland Security (DHS) showcased the timing accuracy and resilience of TerraPoiNT, which delivered timing synchronization better than 50 nanoseconds in urban and semi-urban settings.
As a source of GPS/GNSS-independent time that the U.S. National Institute of Standards and Technology (NIST) determined is highly consistent with Coordinated Universal Time (UTC) — including in deep indoor environments — STL provided the timing signal for the demo instead of GPS.
The advent of the alternative PNT testbed is timely given the recent publication of “Understanding Vulnerabilities of Positioning, Navigation, and Timing” by the Cybersecurity and Infrastructure Security Agency (part of DHS). This important CISA publication urges owners and operators of critical infrastructure to adopt the responsible use of PNT as defined in Executive Order 13905. The new testbed will be used to demonstrate applications for emergency services, telecommunications, financial markets, the electrical grid, and other critical infrastructure sectors.
“Demonstrating the accuracy and resilience of alternative PNT solutions is integral in validating the capabilities of alternative PNT solutions and, ultimately, increasing adoption across use cases and applications,” said Ashu Pande, TerraPoiNT VP at NextNav. “With the development of this testbed, we can emulate real world deployment scenarios and can more effectively instill confidence across the PNT industry in the viability of alternate PNT solutions.”
“The development of this testbed will enable the rigorous, transparent, and replicable testing of alternative PNT solutions,” said Christina Riley, VP of Commercial PNT at Satelles. “We’re excited to be integrated as the GNSS-independent timing reference for this alternative PNT testbed and are looking forward to continuing our collaborative work to build stronger PNT solutions to augment GPS globally.”
The U.S. Department of Transportation categorized TerraPoiNT from NextNav and STL from Satelles as the top-ranked PNT systems in its technology demonstration report released in January. The testbed collaboration between these complementary alternative PNT service providers underscores the companies’ commitment to promoting the adoption of multiple technologies that complement and augment GPS/GNSS to protect the operations of critical infrastructure.
GPS and airborne light detection and ranging (lidar) have revolutionized archaeology. In just a little more than a decade, dozens of previously hidden cities and settlements have been discovered under heavy tree canopy and in other terrain. Many of the sites are in difficult-to-access areas, such as high atop mountains, in vast deserts, or enclosed in thick, nearly impenetrable foliage. Many were only the stuff of legend.
Others are right under our feet. In 2018, early settlements were uncovered in New England, including now-abandoned walls, roads and building foundations.
With the development of lidar, archaeologists gained perhaps their most powerful tool since carbon dating. Lidar began as a million-dollar classified technology. Now lidar units are small enough to attach to unmanned aerial vehicles (UAVs).
Lidar devices send more than 100,000 laser pulses to the ground every second and use their return times to calculate precise elevation data that allow researchers to build three-dimensional maps of a landscape, while GPS receivers provide its coordinates. Lidar fly-overs have revealed ancient cities, temples, causeways, irrigation systems and other structures, which are then ground-truthed by excavation teams.
“Lidar has completely changed the way we survey ancient Maya cities and what we can know about them, and it is a thousand times better than [what we used] before,” Francisco Estrada-Belli told GPS World. Estrada-Belli is a research professor at Tulane University’s Middle American Research Institute.
The application of lidar to archaeology began in 2009, when NASA sponsored a remote-sensing project that showed lidar’s usefulness below the forest canopy. The project revealed the surprisingly vast scope of Caracol, the largest Mayan archaeological site in Belize. Urban Caracol maintained a population of more than 100,000 people with an immense agricultural field system and elaborate city planning.
Since then, lidar has been used the world over to uncover buried secrets from early Roman fortifications in Italy to landscape changes from World War I. Just this August, lidar unearthed sobering evidence of a massacre by Nazi Germany in Poland during World War II.
Image: F. Estada-Belli/Pacunam Lidar InitiativePhoto:
A landmark project in Guatemala illustrates the benefits of lidar. The ancient city of Tikal was one of the best-mapped regions of the Mayan world, but the Pacunam Lidar Initiative quintupled the amount of mapping done in 50 years in a single summer, with 61,000 structures found in an 810-square-mile area invisible to the naked eye because of overgrown vegetation. What experts had mistaken for unusable swampland, for instance, had actually been farmland, crisscrossed with canals. The area may have been home to a population of up to 10 million people. Results were published in Science in 2018.
Seven Solutions sets new record for long-distance White Rabbit high-accuracy time-over-fiber link
The White Rabbit link has an approximate distance of 1,350 km (840 miles) and was deployed in collaboration with Optiver U.S., a financial company, to connect Chicago and New Jersey trading locations. This link is formed by six long-distance White Rabbit hops using WR-Z16 and WR-ZEN TP devices connected by a combination of DWDM and SyncE-compliant transponders over a public telecommunication fiber network.
Seven Solutions is the leading company in the development and integration of high accuracy sub-nanosecond time transfer and frequency distribution for reliable industrial and scientific applications. Their technology integrates the White Rabbit protocol, the basis for the new high accuracy profile in the IEEE 1588-2019 (PTPv2.1).
This technology has become a reference for different sectors thanks to its unprecedented level of accuracy that outperforms current GNSS-based timing solutions, offering a suitable backup solution to deploy time dissemination networks. In the last few years, the White Rabbit technology has been adopted in the finance sector to deploy plug-and-play local area synchronization and metro-area links connecting different datacenters in financial hubs.
Although the performance of White Rabbit long distance links has been previously validated, this deployment sets a new distance record while integrating new resiliency and interoperability features using the latest WR-Z16 and the WR-ZEN TP devices.
Image: Seven Solutions
In a series of experiments, the link accuracy and precision were firstly validated setting a three long-distance hops loopback covering an approximate distance of 800 km (500 miles). In this case, the link was measured using an Agilent 53210A time interval counter for a five-day period. This experiment was intended to validate the feasibility of deploying White Rabbit links using commercial SyncE-compliant transponders and commercial telecommunication networks based on DWDM technologies.
Image: Seven Solutions
This measurement confirms the sub-nanosecond precision on a loopback and made it possible to perform network effect calibration to minimize the residual offset caused by the link asymmetry. In this case, a mean offset of 112 ps, a standard deviation equal to 139 ps and a peak-to-peak difference of 880 ps were obtained. Additionally, the offsets followed a gaussian distribution with no daily trends impacted by temperature or humidity.
This result proves the ability of high-accuracy time-over-fiber dissemination to fulfill the most demanding telecom requirements (class D Telecom Boundary Clocks) and corroborates one of the conclusions from the Analyzing a More Resilient National Positioning, Navigation, and Timing Capability report released by the RAND Corporation earlier this year:
“White Rabbit can support time transfer with accuracy that substantially exceeds the needs of almost all users; it is better than GPS. Therefore, this method is a strong candidate for backing up GPS time transfer for users that require atomic clock accuracy and for serving as a ‘national backbone’ for time so that secondary users, such as cellular networks, can perform to the limits of its own subdomain without suffering additional inaccuracies of its own master clock. Less accurate methods, like ordinary PTP, could provide timing to the vast number of other users, like mobile and cellular users.”
In a second test, the whole link was deployed using GNSS receivers in both ends of the link. The first GNSS receiver was used as the time reference in one end of the link (located in New Jersey) and the second GNSS receiver was used in the second end of the link to compare to the time reference (located in Chicago). Both GNSS receivers are the same model and have a 15 ns RMS jitter specification. In the second location, the local GNSS reference was compared to the remote time reference originating from New Jersey through the long-distance White Rabbit link.
Image: Seven Solutions
This resulted in a mean offset equal to 2.98 ns, a standard deviation equal to 10.4 ns and a peak-to-peak equal to 83.3 ns. It is noteworthy that due to the time interval counter, some of the samples were filtered. This effect is shown on the histogram but is considered negligible to validate the feasibility of the link.
Image: Seven Solutions
Additionally, the White Rabbit protocol automatically corrects daily effects due to temperature or humidity changes in the link, which are not observed in the measurement even when the GNSS receivers are located more than 1,000 km away from each other. This does not represent the real White Rabbit link error but indicates the limitation of using GNSS receiver to accurately measure the link accuracy.
As can be estimated from the measurements, the previous test and the GNSS specifications, the White Rabbit link maintains an approximately ±1 ns precision. In fact, the results show that the GNSS receivers are outperforming their specifications by almost 50%. The final accuracy is influenced by the GNSS receiver calibration. This link can be calibrated using network effect techniques (as shown in the previous experiment) or using the GNSS receivers themselves.
This experiment complements the results obtained in the U.S. Department of Transportation GPS backup demonstration showing the White Rabbit technology (which was catalogued as the most accurate alternative technology for time distribution) in a real telecommunications network scenario with very long distances. Additionally, it justifies the industrial need to deploy high accuracy time distribution when providing an alternative to GNSS-based timing, as it provides a next generation technology that can benefit other PNT systems and several critical infrastructures that rely on time synchronization for daily operations.
Beyond this, White Rabbit is demonstrated as a disruptive technology that can be used to measure the performance of GNSS in various locations to develop a warning and backup system, to connect high stability time references (for example, atomic clocks) for a suitable long-term ground-based backup to GNSS systems or to connect national metrology institutes around the world to compare different time scales.
This long-distance link represents a new milestone in ultra-accurate time transfer over existing telecom networks that allows cross-validating different linked references or accurately synchronizing them for coordinated actions at tight relative timing.
Furthermore, the deployment through existing telecom network proves its feasibility at affordable cost and opens the door to new disruptive applications. Atomic clocks have evolved to represent very stable references, but it has been typically assumed that time degrades as it is transferred over long distances making accurate comparisons between different references a challenge. This new generation of long-distance links represent a step further into tightly synchronizing different devices over fiber at long distances making them resilient to the vulnerabilities of GNSS timing.
This level of accuracy is key for certain applications and sectors nowadays. Matt Nassr, Data Engineering Lead at Optiver, remarked “Partnering with Seven Solutions has allowed us to better optimize for the highly distributed nature of the financial markets. Being able to establish a nanosecond-level precision link across the Chicago-New Jersey path further improves our ability to provide liquidity across the major US exchanges.”
“This is not a first step on the deployment of long-distance time synchronization networks, this is just one step further,” said Francisco Girela, Americas tech responsible at Seven Solutions. “We have been working for years on improving our devices, easing the monitoring and management, enhancing the resiliency, integrating failover features, adding interoperability with IEEE 1588 (PTP), NTP or PPS and allowing the integration of High Accuracy timing in third party devices thanks to the HATI core. During this journey we have learnt how to integrate the technology to work at its best and we have proved its effectiveness in telecom, data centers, finance, defense, or power grids among others.”
When asked about next steps, Francisco added, “We want to demystify this technology. People think that its deployment is complex or overkill, but that is not true. We see White Rabbit as the core technology to build alternative PNT systems, setting a sub-nanosecond timing foundation that will push the development of a more diverse and more accurate technology ecosystem.
“We have worked to evolve White Rabbit devices to be a market commodity when deploying time synchronization in local areas but providing a level of accuracy that will fulfill the requirements for the current applications and for the next decade. For long distances, complex deployments, or projects we are always happy to assist our customers and partners to get the best from our devices. We are sub-nanosecond natives; we care for every single picosecond.”
