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Another year has come and gone. The global pandemic of COVID-19 is still upon us, and while we have experienced peaks and valleys of controlling the virus, it has radically changed our lives in many ways.

The surveying and geospatial professions have not been immune to the effects of the pandemic. It has forced many practitioners to modernize the means and methods to their workflows and products.

In this edition of Survey Scene, I consider the changes and accomplishments of 2021, and take a look ahead at events and technological advances to come.

2021: The Road We Traveled

Despite the pandemic, technology within the geospatial professions grew at a rapid pace, with new equipment and features. From the air to the seas, geospatial data-collection capability increased in varying ways across the differing environments.

Unmanned Aerial Systems (UAS)

The technological explosion of unmanned aerial vehicles (UAV) shows no signs of slowing down and manufacturers remain hard at work developing new designs for longer flights and increased capabilities. Lidar has emerged as the “hot” remote-sensing method for many users of UAS as an additional tool for photogrammetric capabilities, yet camera specs continue to grow well beyond the 20-megapixel expectation of recent years. These increased capabilities were not possible simply because of the amount of data generated by the methods, but previous issues and limitations with computing power and data storage have turned a significant corner in software performance and affordability.

In addition to the implementation of lidar, further developments in multirotor and fixed-wing UAV design continue to improve the performance and capabilities of the data-collection task. Many companies are growing their fleets to include both types of UAVs for varying conditions and applications.

Unmanned Ground Vehicles (UGV)

The sector with the most surprising developments has to be the unmanned ground vehicle (UGV) — but not for the reasons most would have predicted. We have been introduced to several products based upon remote-control vehicles utilizing GNSS positioning over the past few years, so it was expected for that trend to continue and grow.

To say the industry was taken aback when Leica partnered their BLK scanning technology with the Boston Dynamics new robot “Spot” would be an understatement. Trial projects and testing is ongoing, but the concept of autonomous data collection by a robotic “dog” is an intriguing concept, especially in environments where human presence is dangerous.

Unmanned Surface Vehicles (USV) and Unmanned Underwater Vehicles (UUV)

The last two autonomous vehicles used by geospatial professionals saw significant advancements as well, and are seeing increased use for many water-based remote-sensing projects. For many bathymetric surveyors, the small-footprint unmanned boat using GNSS positioning and conventional fathometer has been a game changer.

In addition to not investing large sums in a conventional boat, a USV is able to navigate many places and shallower depths than its larger counterparts. Like its airborne and ground cousins, battery life and advancing designs are creating more capability for data collection and remote sensing. The old saying “the sky is the limit” for emerging technologies does not apply to unmanned vehicles, as their use is being seen in almost every environment.

Professional Societies/Events/Education

As the calendar pages turned from 2020 to 2021, our world had begun a slow ride back to normalcy with the introduction of several variations of a vaccine for COVID. Some communities chose to return to face-to-face meetings, while others remained cautious and continued with remote communications. Here is a recap of how various organizations remained active within the professional community:

• National Society of Professional Surveyors (NSPS) and its state affiliates: In-person resumption for some, while most continued with hybrid and/or remote communication methods.
• International Federation of Surveyors (FIG). Annual working week was held remotely.
• Council of European Geodetic Surveyors (CLGE). Various meetings held in-person and remotely.
• Global Surveyors Week. Hosted by CLGE and held remotely.
• NGS Seminars. A variety of seminars throughout the year held online.
• Survey & GIS Summit. Joint conference hosted by NSPS and URISA held online.
• Intergeo. Return to in-person with hybrid option.

Educational institutions worldwide struggled with returning to in-person classes, yet technology has allowed for remote communication and continued teaching. While many may still see remote learning as a hindrance, improved technology and communication methods have allowed us to continue to learn, work and simply converse with others. Without these tools, life as we know it would be impossible.

Legislation and Government

While much of the attention within legislative arenas was on social and economic issues, the geospatial community continues to monitor several items that potentially have a large impact on the profession.

The continuing saga of Ligado (formerly known as LightSquared) is still playing out, despite the outcry by many industry users of GPS technology. The Federal Communications Commission (FCC) authorized Ligado to begin construction of its new 5G communications technology and denied any stays to this order. Many groups, including coalitions of geospatial data users, continue to protest the authorization by the FCC.

In December 2021, the airline industry, along with Boeing and Airbus, expressed its concerns over the implementation of the new communication technology and the potential interruption of GPS and radio guidance for aircraft. Only time will tell if efforts to derail the installation and use of the new 5G communication band will be successful

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Elimination of the professional license requirement for surveyors is quite dangerous and foolish.

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Another large issue on the horizon for surveying and geospatial professionals is licensure deregulation. Currently, each state in the U.S. is responsible for licensing and oversight of professionals as established within their statutes. Several consumer groups have begun to petition a number of states to eliminate licensing as a barrier to entry into a given profession, including surveying. They also cite the cost of regulating the professions as an unnecessary expense to the residents of their states.

Unfortunately, these groups are shortsighted about the education and training required to become licensed within each profession to protect the public they serve. While the costs associated with purchasing the technology needed for the profession continues to decline, the expertise and training needed is on the rise. Elimination of the professional license requirement for surveyors is quite dangerous and foolish.

2022: The Road Ahead

As we look ahead, we are still facing many challenges left over from the past few years. Obviously, the COVID-19 pandemic will continue to twist and turn with new variants, enhanced vaccines and adjustments to many aspects of our lives. Because of technology and much different lifestyles from earlier pandemics, we are continuing to adapt to environmental changes: much of business goes about as close to “normal” as possible.

One could say that creativity and innovation has increased because of the pandemic and probably not get much of an argument. So where do we see technology and the geospatial profession heading during 2022?

Technology Evolution

More people are using technology and computing power than ever before and in ways probably not considered even 10 years ago. Until recently, data — especially personal information —has been considered off-limits for public consumption. Only governments were allowed to obtain scores of data to help keep track of literally everything.

Once geospatial technology came along, the game changed to include a location or positional component to a dataset. Now data can be saved to include a place and time for a particular piece of information if necessary.

Databases continue to grow with computing and software enhancements, storage increases and expanded network capability. So where are all of these cutting edge technologies taking the surveying and geospatial professions? Here are ways that continuing technological improvements are advancing our capabilities.

Open-Source Data

While in the past data was typically considered proprietary, many of the datasets used by geospatial professionals do not contain personal information. This information is simply physical location data for improvements and infrastructure that can be shared openly with no risk of compromising personal security.

Examples of open-source data cover many subjects, including shape files of physical objects, lidar and contour data of existing topography, and aerial imagery of the world we live in. It can also include data such as traffic counts, air-quality reporting and general population data.

Much of this data is secured using public funding, but it is not able to be readily shared because of database size limitations. Increases in technology have allowed this information to be shared more freely, and that has given professionals more information in which to better design infrastructure.

Artificial Intelligence (AI) and Machine Learning

Trainable technology is nothing new, but the computing power behind it has rapidly increased to make it a formidable challenge to our future workforce. Besides robotic machinery, sophisticated software is being developed to analyze various datasets and electronic mediums to “learn” about the information it contains.

For example, AI is being used to analyze photographic imagery and lidar datasets to determine characteristics of various elements within the work product. The software can now establish a painted parking line and draw a vectorized line in all places where it finds the same pixelated areas.

This same process is used to determine curbs, buildings and other improvements with an efficiency of which the human surveyor on the same site isn’t capable. While not foolproof, the technology has great potential and can shrink production time drastically. As programming continues to become more robust in determining the computer’s abilities, we should not bet against this market sector achieving anything but rapid growth. Couple these advancements with the shrinking workforce, and we will continue to see much more from this technology.

High-Performance Computing via Cloud Networks and Storage

Before the personal computer (circa 1980), most data processing was completed on a mainframe using terminals and primitive networks. No true computing brainpower was sitting on the user’s desk; the keyboard and monitor were simply conduits to the main processing computer typically housed in a large room somewhere in the building.

Fast forward to today’s environment, in which everything can be considered a computer. As many have noted, your current smartphone has more computing power than we used to reach the Moon. (The Apollo guidance computer had 4 KB of RAM and a 32-KB hard disk; it measured 24 x 12 x 6 inches and weighed 30 kg). Computing power at your fingertips has never been greater, but our improving technology is making today’s current data analysis seem like child’s play.

Enter the world of cloud computing and storage. If you live in a major metropolitan area, you have likely been witness to nondescript buildings being constructed with lots of transformers and electrical grid units surrounding them. These facilities are data centers and are being built at breakneck speed by Google, Microsoft, Facebook, Amazon and others to provide cloud computing and storage for the masses.

The cloud computers offer unmatched processor speed, nearly unlimited storage and reduced IT management costs. Large datasets being analyzed for specific algorithms can utilize cloud computing at a fraction of the cost of maintaining a personal computing system and network. It also allows the flexibility to work from literally anywhere in the world, yet have a consistent computing presence where you are. The big downside is that one is dependent on a reliable (and fast!) connection, as well as needing a comfort level with someone else having access to your data.

Other major areas of technology that will see improvement this year include 3D visualization (AR & VR), remote sensing, massively online open courses (MOOC) for higher learning, blockchain utilization, and an increase in the number of devices using internet of things (IOT) programming. The key to staying in front of these technologies is to remain curious and never stop learning!

A Personal Note for 2022 and Beyond

Like many jobs in this age of advancing technology and automation, surveying is quickly becoming an endangered profession. There are many facets in our everyday lives that are the responsibility of a surveyor, but the number of practitioners is dwindling. The pandemic may have turned our world upside down for many reasons but for surveyors and geospatial professionals, it increased our visibility and workload. Attrition will claim many within our ranks over the next several years, so we must find a way to prolong our profession through all avenues.

With this in mind, I am proud to announce my appointment as the new executive director of the National Society of Professional Surveyors (NSPS). My years in the private sector have provided me with a broad view of where we face professional challenges, so transferring into an advocacy role will allow me to help solve those challenges.

It will be my honor to work with our organization to recognize the threats lying ahead, not just for surveyors but for many other geospatial professions and occupations. We also recognize that inclusion is a key component to creating diversity, as technology does not see a difference in nationalities, races and genders. The future of surveying is very bright, and NSPS is continuing to lead the way in creating a positive career path for our future surveying and geospatial professionals.

Helix Geospace, an innovator in antenna and RF technology, has raised £3 million seed funding in a round led by Bloc Ventures and supported by the UK Innovation and Science Seed Fund (UKI2S).

Helix builds precision GNSS antennas that enable product designers to create small, accurate positioning, navigation and timing (PNT) synchronization products that defend against vulnerabilities and threats. Helix is also developing its antennas to provide navigation for autonomous vehicles.

Helix’s patented DielectriX antennas are targeted initially to receive PNT signals from GNSS (GPS, Galileo, GLONASS, Beidou) constellations, and the Satelles STL (Satellite Time and Location) signals delivered over the Iridium constellation as well as Iridium’s voice and data network.

Future antenna variants will support low-Earth orbit (LEO) PNT services being planned and built by private companies, as well as government agencies, the company said.

DielectriX antennas discriminate true satellite signals from multipath signals, interference and jamming, delivering high performance in a compact and rugged form factor. Helix’s customers include defense, automotive, aerospace and critical infrastructure companies.

Helix previously raised £2.5 million from UKI2S and angel investors, and has participated in Wayra UK’s Intelligent Mobility Accelerator programme and Seraphim Capital’s Space Camp Mission 6. Helix also received additional grant funding for advanced antenna development from the European Space Agency, and for anti-jamming/spoofing technology from UKI2S.

Boeing has secured a 10-year, $329.3 million contract to help the U.S. Space Force engineer operational GPS Block IIF satellites, the Department of Defense announced Dec. 20.

The company will perform engineering work to support on-orbit operations of the Block IIF satellites, which were manufactured by Boeing.

Space Systems Command issued the indefinite-delivery/indefinite-quantity contract to address GPS IIF mission requirements across the military and expects work to conclude by Dec. 20, 2031.

The U.S. Air Force deployed the first Boeing-built IIF satellite in May 2010 and launched the 12th and final satellite in February 2016.

Tokyo-based Kudan Inc. demonstrated the use of a 3D-lidar simultaneous localization and mapping (SLAM) device to create a sharp point cloud without using an external GNSS receiver or inertial measurement unit (IMU).

Kudan is a research and development company specializing in algorithms for artificial perception. For the demonstration, Kudan used its localization and mapping software Kudan 3D-Lidar SLAM, or KdLidar.

Using an Ouster OS1-64 lidar and only its internal IMU, Kudan demonstrated how it can create a crisp high-resolution point cloud with KdLidar.

For the demonstration, the company used a handheld scanner with the Ouster lidar. Handheld scanners can introduce noise and fuzziness in typical point clouds generated from SLAM because of natural vibration, movement and limited field of view. However, Kudan was able to capture sharp wall definition of buildings and structures, as well as the fine detail of powerlines.

While the demonstration highlights KdLidar’s basic performance without any external sensors, the company said its algorithms can further increase the performance and quality of lidar-based scanners by fusing GNSS receivers and external IMUs or inertial navigation systems.

Column provided by Septentrio

For navigation and control of any robotic or autonomous outdoor system, GNSS and inertial navigation systems (INS) are key components. Inevitably, the question arises: Should you build your own custom solution or integrate an available GNSS/INS combined solution? What would give you the best performance, while keeping the total cost of ownership (TCO) to a minimum? The TCO is also known as the “long-term price” and is defined as the purchase price plus the costs of operation over time.

Xenomatix is a company offering automotive solutions based on lidar technology. With eight years of innovative experience, Xenomatix has installed a pre-integrated GNSS/INS receiver on its latest lidar product, achieving high GNSS/INS performance with minimal TCO.

In an integrated INS/GNSS receiver, the GNSS receiver provides positioning with centimeter-level accuracy. The other component is a micro-electromechanical inertial measurement unit (MEMS IMU), which measures 3D orientation in terms of heading, pitch and roll angles with sub-degree precision. For its latest product XenoTrack, Xenomatix chose an INS called XenoAsterx based on the AsteRx SBi3 from Septentrio, which it integrated alongside its lidar to collect road-quality data to the smallest detail.

From an in-house solution to a pre-integrated system

Three years ago, when Xenomatix started developing its new lidar road-inspection system, the company had a GPS receiver, an IMU and an odometer as accompanying sensors. The company wanted to expand into new markets of road inspection in accordance with international standards, and so it needed to improve its components to take the overall performance of its system to the next level with RTK high-accuracy positioning.

To achieve this, while saving time and costs, Xenomatix acquired an AsteRx SBi3 INS/GNSS receiver, which allowed it to focus on its core lidar technology and sensor-fusion algorithms.

This off-the-shelf INS/GNSS solution provided all the high-accuracy positioning and orientation information Xenomatix needed, while eliminating most costs of development, maintenance and support. The new receiver allowed them to drive for miles, without any offset in positioning, something impossible with the previous GPS receiver.

The unique technology from Xenomatix stitches images by using lidar point-cloud overlays. However, when the car is moving fast, this overlay is smaller. The pre-calibrated GNSS/INS extends system performance by allowing stitching even when driving at higher speeds.

“If we start driving and we stitch the road for tens of kilometers and we come back to the same starting point, then we see an offset of only a few millimeters,” said Filip Geuens, CEO, Xenomatix. “This is for us the strongest proof of accuracy and reliability of the GNSS sensor.“

Why pre-integrated GNSS/INS offers better value

A pre-integrated GNSS/INS solution — versatile enough to fit into virtually any autonomous or mapping system — offers the best value in the long run for the following reasons.

Better performance. The manufacturer of a GNSS/INS solution specializes in fusing the GNSS receiver and the INS in an optimal way. To accomplish this, the sensors are synchronized and their output run through a sophisticated Kalman filter algorithm. The fused device is then fine-tuned for optimal operation under various conditions. Finally, it is extensively tested and validated.

While being used by numerous customers and in varying applications, the GNSS/INS solution proves itself on various levels such as accuracy and robustness. This results in superior performance, even in the most demanding environments.

After installing the AsteRx SBi3 GNSS/INS system, XenoTrack was able to extend its functionality to inspect longer distances of roads at higher speeds. The AsteRx SBi3 operates reliably, even in challenging environments, such as when driving near high cliffs or under bridges.

Less development time and lower costs. When building a system, the development time is usually about one year employing two full-time GNSS/INS specialists. Hardware components need to be integrated and synchronized, while various interfaces and the Kalman filter need to be implemented. Additional features may be developed, such as velocity input as well as tools for validation, before the intricate step of performance fine-tuning. Finally, additional testing efforts are needed for verification and validation of the device.

On the other hand, a pre-integrated GNSS/INS system with easily accessible interfaces and flexible configuration ensures quick installation, meaning the product is ready within weeks.

Lower maintenance costs and support. Certain high quality pre-integrated GNSS/INS receivers are future-proof — ready to use new GNSS satellite signals and services as soon as they become available. An example of such upcoming service is the Galileo OSNMA anti-spoofing authentication.

Some receiver manufacturers such as Septentrio also offer continuous product improvement in the form of free firmware updates. A system developed in-house, on the other hand, needs continuous investment to maintain its competitive edge.

When issues occur, Septentrio also offers local worldwide support, with experienced application engineers ready to solve GNSS, INS or coupling issues that could halt the production process. For example, when Xenomatix discovered that its GNSS/INS was not working optimally in a certain environment, the company called Septentrio. Within days application engineering experts who analyzed the logged data found the source of the issue and proposed a solution.

Focus on core technology. When the budget is limited, choices need to be made about where to focus the efforts. When a company saves on GNSS/INS development, more can be invested in core technology. This means avoiding any lost-opportunity costs and optimizing margins.

Building your own is not always the best option

Acquiring a pre-integrated GNSS/INS receiver allowed Xenomatix to have a superior and affordable product with a competitive edge. AsteRx SBi3 increased the performance of the XenoTrack mapping system, while a short integration period allowed a faster time-to-market.

Xenomatix also benefited from low maintenance costs, keeping overall TCO to a minimum. Since the company was not spending time developing a custom GNSS/INS system, it could focus fully on its core technology. This allowed Xenomatix to take its business to the next level at a high pace.

Award-winning technology

In November 2021, the XenoTrack road scanner, with AsteRx SBi3 inside, was announced a winner of the IRF Global Road Achievement Award for its innovative road scanning and surveying solutions.

U‑blox has announced the NEO-M9V module, its first GNSS positioning receiver to offer both untethered dead reckoning (UDR) and automotive dead reckoning (ADR).

The NEO-M9V is suitable for fleet management and micro-mobility applications that require reliable meter-level positioning accuracy even in challenging GNSS signal environments such as urban canyons.

Vehicle fleet managers seeking to cut costs and lower their carbon footprint depend on accurate positioning and navigation data to reduce fuel consumption. Micro-mobility operators need to accurately locate their individual bikes and scooters.

Using inertial sensor measurements, UDR offers a smooth navigation experience in dense urban environments by bridging gaps in GNSS signal coverage and mitigating the impact of multipath effects caused by GNSS signals that bounce off buildings. ADR further increases positioning accuracy in demanding environments by including the vehicle speed in the sensor-fusion algorithm.

Offering both UDR and ADR on the same module delivers maximum positioning performance and design flexibility, u-blox said. The NEO-M9V also features dynamic models optimized for both cars and e-scooters.

NEO-M9V is based on the u‑blox M9 GNSS technology platform. Its ability to track up to four GNSS constellations maximizes the number of GNSS satellites within its line of sight at any given moment. Integrated SAW and low-noise amplifier filters offer excellent interference mitigation for a robust solution. Compatibility with the NEO form factor reduces migration efforts for customers upgrading existing designs.

An Info Note has been published with analytical information on the Galileo Open Service – Navigation Message Authentication (OSNMA). The note is available on the European Union Agency for the Space Programme (EUSPA) website or through the European GNSS Service Centre. To contribute to the detection of GNSS jamming and spoofing attacks, EUSPA together with the European Commission is testing OSNMA.

This forthcoming service is an authentication mechanism that allows Open Service users to verify the authenticity of GNSS information, making sure that the data they receive is indeed from Galileo and has not been modified in any way.

OSNMA is authenticating data for geolocation information from the Open Service through the Navigation Message (I/NAV) broadcast on the E1-B signal component. This is realized by transmitting authentication-specific data in previously reserved fields of the E1 I/NAV message. By using these previously reserved fields, OSNMA does not introduce any overlay to the system, thus the OS navigation performance remains untouched.

Authentication is set to further strengthen service robustness by increasing the capability of detecting spoofing events. However, it should be kept in mind that authentication does not prevent the occurrence of such an event, and does not protect against jamming. Nonetheless, this added layer of protection proposes to be one step ahead of evolving technological trends by amplifying the service’s overall robustness and resilience.

News from the Air Force Research Laboratory

The Air Force Research Laboratory’s complementary positioning, navigation and timing (PNT) AgilePod prototype achieved three important objectives in flight tests conducted at Edwards Air Force Base Nov. 1-10, 2021.

PNT AgilePod helps develop advanced navigation technology independent of GPS, according to Maj. Andrew Cottle, Air Force Strategic Development Planning and Experimentation (SDPE) office. This technology provides reliable, resilient PNT navigation signals through alternative means, increasing mission effectiveness in scenarios where access to GPS is not guaranteed.

The test team — representing a broad base of Air Force, Navy and vendor organizations — successfully executed eight sorties aboard a T-38C aircraft, which included:

• the first test of the PNT AgilePod on a high-dynamic-range platform
• the first test of fully remote interfacing and alt-PNT data transmission
• the first demonstration of overland/overwater transition performance.

He said the tests demonstrated the operational utility of a fused alt-PNT system incorporating multiple technologies within a single government-owned open-architecture prototype.

AgilePods Designed for Flexibility

AgilePods are comprised of a series of compartments and can be configured to meet a wide variety of mission requirements for many aircraft platforms. Experimenters can fill the spaces with plug-and-play sensors they need for a mission — high-definition video, electro-optical and infrared sensors, and devices with other capabilities — including PNT.

The AgilePod is has an open hardware architecture. For the complementary PNT prototype, it was combined with an open software architecture that allows a wide variety of alternative PNT technology to integrate and pass information. These capabilities enable rapid integration of sensor technologies through standardized software and hardware interfaces, allowing the pod to seamlessly integrate on platforms that leverage the standard architectures.

In this way, one pod can perform hundreds of different mission sets with additional benefits of cost savings and increased sustainability, Cottle said.

The project directly supports the AFRL PNT Enterprise and the Air Force PNT Cross-Functional Team as they work to ensure reliable navigation within GPS-contested operational scenarios critical to the success of future Air and Space Force missions.

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.

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.

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.

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.

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.

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.

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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.

ION’s winter meeting, the International Technical Meeting (ITM), is a more intimate conference with a technical program related to positioning, navigation and timing and includes the ION Fellows and Annual Awards presentations.

In 2022, ITM will take place in Long Beach, California, January 25- 27, 2022, and will be co-located with the Precise Time and Time Interval Systems and Applications Meeting. ITM will house more than 150 in-person and virtual technical presentations, two keynote addresses, six tutorials, and an exhibit hall filled with the latest PNT solutions.

A commercial exhibit and pre-conference tutorials are held in conjunction with the conference.

Tutorials will be offered as part of this year’s in-person technical program on January 26 and will be open to all in-person PTTI and ITM attendees. Tutorials cover novel systems for time distribution from space, atomic clocks, Kalman filtering for clock estimation, and specific implementations for time distribution from space.

The ITM/PTTI plenary session will be recorded and uploaded to the website for on-demand viewing. No other ITM/PTTI sessions (including tutorials) will be recorded for on-demand viewing. All presenters are required to provide a video presentation for on-demand viewing. On-demand presentations will be available through the ITM/PTTI meeting portal for 30 days.

To view the ITM/PTTI 2022 technical program and to register, go to https://www.ion.org/itm/registration.cfm.