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The European Commission has issued industrial contracts worth €1.47 billion ($1.97 billion) to build next-generation Galileo satellites to Airbus and Thales Alenia Space, reports BBC News.

Both companies told BBC News that they will not speak publicly about their contracts wins until documents are signed, which could take several weeks.

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Read more about Galileo and its plans in Directions 2021: Galileo expands and modernizes global PNT by Javier Benedicto and Rodrigo da Costa.

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Each contract is for manufacture of six satellites, to orbit no earlier than 2024. They will feature digitally configurable antennas, inter-satellite links, new atomic clocks and propulsion systems that use electric engines.

Airbus and TAS built the four Pathfinder in-orbit validation satellites that first demonstrated Galileo. A consortium of OHB-System and Surrey Satellite Technology Ltd. built the first operational Galileo satellites, but the consortium ended following Brexit.

George Mason University has revised a briefing paper on positioning, navigation and timing (PNT) in response to concerns about its accuracy.

The university’s National Security Institute “NSI Backgrounder — Beyond GPS: The Frontier of Positioning, Navigation, and Timing Services” was first issued on Dec. 2. Some staff on Capitol Hill and members of industry soon had concerns about several of its assertions.

Responding to letters from industry, National Security Institute (NSI) Executive Director and Professor Jamil Jaffer said he determined that three of the issues raised, while not fatal to the document, warranted clarification.

ELoran callout. The first was a statement in the backgrounder that the National Timing Resilience and Security Act (NTRSA) “specifies 13 technical requirements for a GPS backup, which essentially define the eLoran system.”

This was a concern to some on the hill as Congress is generally reluctant to specify solutions. Legislators prefer to specify outcomes and then defer to the executive branch on how to make them happen.

Members of industry pointed out that government systems like WWVB and the low-frequency portion of DARPA’s STOIC program, as well as commercial systems like NextNav and Locata, could meet or be adapted to meet the NTRSA requirement.

The revised backgrounder says the NTRSA “specifies 13 mainly technical requirements for a GPS back-up, which align closely with the capabilities of the eLoran system. Other systems may meet the Act’s requirements to varying degrees.”

Multiple technologies. The revised backgrounder also corrects a statement that the NTRSA requires the Department of Transportation to establish an eLoran system. It now says “a system that complies with the Act, and DOT may pursue multiple technologies in implementing the Act.”

Department officials had previously said they were taking a system-of-systems approach and expected to employ multiple technologies. Subsequently, a DOT report was released that documents the need for several diverse systems. It lists transmissions using low frequency (eLoran, STOIC), ultra high frequency (NextNav, Locata) and L-band from space (GPS, Satelles). It also says the terrestrial transmitters should be interconnected by fiber.

Public-private partnership. A third correction was made in the document to reflect how the Congressional Budget Office regarded the possibility of using a public-private partnership in previously proposed legislation.

Members of industry also expressed concern that one of the authors of the document serves on the advisory board for Satelles Inc. and that this was not disclosed in the paper. The backgrounder appeared on the Satelles website the same day it was published.

The university concluded that such disclosure was not necessary as the paper said the author “provides advisory services to industry, including in the PNT area.” At the author’s request, though, his profile on NSI’s webpage will be updated to show his relationship with Satelles.

Senate joined House to override Trump’s veto, making bill into law

The U. S. Congress, especially the Armed Services Committees, have long been concerned about GPS and positioning, navigation and timing (PNT) issues. Over the past two decades, Congressional hearings, demands for reports and investigations have dealt with acquisition, contingency plans for when space is not available, deliberate interference, and a host of other issues.

While these all evidenced Congress’ interest and concern, they were relatively passive measures.

This began to change in 2018 with passage of the National Timing Resilience and Security Act. It requires the Department of Transportation to establish a terrestrial timing system to backup GPS signals.

Then in 2019, Congress appropriated money for a GPS Backup Technology Demonstration. And the National Defense Authorization Act (NDAA) for 2020 required the Air Force to develop a prototype multi-GNSS receiver as part of its resiliency efforts.

The NDAA for 2021 seems to finalize Congress’ transition from an interested observer, mostly on the sidelines, to an active player in national PNT issues and policy.

GPS Under Threat

Capitol Hill observers say this is the result of several factors that have come to a head over the last year. Taken together, they have convinced many legislators that GPS is under threat and PNT issues are not being taken seriously enough by the executive branch. These include increased jamming and spoofing (especially by China and Russia), full implementation of China’s BeiDou system and its marketing to other nations as a superior alternative to GPS, the Federal Communications Commission’s (FCC) decision on Ligado Networks, and the Pentagon’s failure to respond to combatant commanders’ Joint Urgent Operational Needs Statements for non-GPS PNT.

Here are some of the provisions of the 2021 NDAA of interest to the PNT community.

Military Multi-GNSS Prototype

The 2018 NDAA required the Defense Department to incorporate Europe’s Galileo and Japan’s QZSS satellite navigation signals into military user equipment. The idea was to make it more resilient to disruption. Also required was an investigation into using non-allied signals.

Apparently not satisfied with progress on this project, Congress mandated a project to develop a prototype multi-GNSS receiver as part of the 2020 NDAA.

The 2021 NDAA seems to indicate Congress is still not happy. It withholds 20% of the funding for the Office of the Secretary of the Air Force until the department certifies the prototype project is underway and provides briefings to the Senate and House Armed Services Committees.

Resilient, Survivable PNT

Language in the 2021 NDAA also seems to show Congress is impatient with the Pentagon’s lack of responsiveness to combatant commanders’ requests for non-GPS PNT systems.

Section 1611 of the act is entitled “Resilient and Survivable Positioning, Navigation, and Timing Capabilities.” It requires development, integration and deployment of these capabilities for combatant commanders within two years. This, it says, is “… consistent with the timescale applicable to joint urgent operational needs statements…”

The act says the new PNT capabilities shall “generate resilient and survivable alternative positioning, navigation, and timing signals” and “process resilient survivable data provided by signals of opportunity and on-board sensor systems…”

The act also addresses the Defense Department’s 2018 PNT Strategy’s plan for future systems to be classified and for military use only. It directs the department to work with the National Security Council, Departments of Transportation, Homeland Security and others “…to enable civilian and commercial adoption of technologies and capabilities for resilient and survivable alternative positioning, navigation, and timing capabilities to complement the global positioning system.”

To help ensure prompt action on this, the act requires a report to Congress within six months and authorizes the department to reprogram funds from other areas to finance the effort.

Responding to Ligado Decision

By far the most PNT-related text in the 2021 NDAA includes a host of measures responding to FCC Order 20-48 approving an application by Ligado Networks. An order that the executive branch is on record as strongly opposing, saying it will degrade GPS service for many.

Senator Jim Inhofe, chair of the Senate Armed Services Committee, has regularly expressed outrage at the FCC’s decision and has called for its reversal.

Among its provisions, the act:

• requires the Department of Defense to estimate and report to Congress the cost of damage to department systems as a result of the FCC order.
• prohibits using department funds to upgrade or modify military equipment to make it resilient to interference caused by broadcasts in the spectrum allocated (the FCC order requires this to be funded by Ligado).
• prohibits contracting with any entity using the frequency bands allocated to Ligado unless the Secretary of Defense certifies the use will not interfere with GPS services.
• requires the Secretary of Defense to contract with the National Academies of Sciences, Engineering, and Medicine for an independent technical review of the FCC order.

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

Findings show accuracy of new sensors is improved by greater than an order of magnitude over current offerings.

Honeywell, with funding from the U.S. Defense Advanced Research Projects Agency (DARPA), is creating the next generation of inertial sensor technology that will one day be used in both commercial and defense navigation applications.

Recently, findings gathered in Honeywell labs have shown the new sensors to be greater than an order of magnitude more accurate than Honeywell’s HG1930 inertial measurement unit (IMU) product, a tactical-grade product with more than 150,000 units currently in use.

An IMU uses gyroscopes, accelerometers and electronics to give precise rotation and acceleration data to enable a vehicle system to calculate where it is, what direction it is going and at what speed, even when GPS signals aren’t available.

There are various types of IMUs on the market, and some — like the next-generation version currently under development — use sensors based on micro-electromechanical systems (MEMS) technology to precisely measure motion.

“Typically, MEMS inertial sensors have been on the lower end of the performance scale, but this latest milestone shows we are changing that paradigm,” said Jenni Strabley, director of offering management for Inertial Sensors, Honeywell Aerospace. “With this next-generation MEMS technology, we’re increasing performance without having to significantly change the size or weight of the IMU. This is a game-changer for the navigation industry, where customers need highly accurate solutions but cannot afford to compromise on weight or size.”

Over the past few years, Honeywell has been working with DARPA to develop the next generation of high-precision navigation-grade IMU technology, under the Precise Robust Inertial Guidance for Munitions: Thermally Stabilized Inertial Guidance for Munitions (PRIGM TIGM) program.

The new MEMS sensors will use different sensor designs and electronics to enable higher performance. They will serve a broad range of applications in autonomous land and air vehicles for both military and commercial customers, including future urban air mobility aircraft.

“Now that we have demonstrated that MEMS is capable of reaching these incredibly precise performance levels, it is the perfect time to start talking with potential users about how this technology could help their applications,” Strabley said. “We believe this new technology will have a variety of applications, such as onboard future vehicles that will fly in urban environments where lightweight, extremely precise navigation is critical to safer operations. Additionally, there are other applications that haven’t been invented yet but may be enabled by these types of technology innovations.”

Commercial sales of an IMU containing these next-generation sensors are still several years away, but one of the first products using this new technology is expected to be more than 50 times more accurate while roughly the same size as Honeywell’s IMU.

Honeywell has long been a pioneer in MEMS-based IMUs, including the HG1930. Honeywell’s lineage in navigation dates to the 1920s and since then Honeywell has developed and manufactured high-performance navigation solutions found on many aircraft and other vehicles worldwide.

Harxon has introduced its TS112 family of smart antennas for demanding applications such as agricultural machine autosteering systems that require high positioning-accuracy. Harxon made the introduction in a virtual meeting on Jan. 13 from Shenzhen.

The TS112 family features Harxon’s latest GNSS positioning technology and offers scalable positioning solutions with increased GNSS availability, reliability and accuracy.

Each of the three models embed Harxon X-Survey four-in-one technology. The high-gain and wide beamwidth multi-constellation GNSS antenna integrates 4G, Bluetooth and Wi-Fi in one compact unit. They feature multi-point feeding technology, ensuring high phase-center stability and real-time kinematic (RTK) centimeter-level positioning accuracy.

The TS112SE, as the most affordable solution of the three, provides flexible positioning solutions via standalone positioning or dual-frequency precise point positioning (PPP) with accuracy from sub-meter to centimeter level while using Sapcorda’s SAPA (Safe and Precise Augmentation Service). Its comprehensive support and L-band augmentation service ensure solid satellite tracking without signal outage even in difficult terrains or problematic environmental conditions.

SAPA works as a reliable alternative economical positioning option with wide service coverage in the application environment that has poor LTE network coverage.

The TS112 integrates a high-precision GNSS module with multi-band GNSS receiver and Harxon’s four-in-one multifunctional GNSS antenna in a compact housing. It supports dual-frequency multi-constellations for consistent and robust satellite signal tracking and delivers RTK-level positioning accuracy for precision agriculture equipment and machine control. It offers a 4G and UHF radio modem for flexible correction transmission as well as wireless Bluetooth technology for easy connectivity in the field.

The TS112 PRO employs a future-ready NovAtel OEM GNSS module, offering precise positioning and advanced interference mitigation for space constrained applications and challenging environments.

With centimeter-level positioning utilizing TerraStar satellite-delivered correction services, Harxon’s TS112 PRO ensures globally available, high performance positioning without the need for network infrastructure. Harxon’s TS112 PRO also support NTRIP service, so in application environments where using a base station is not feasible, the NTRIP differential corrections could be transmitted to a rover using 4G networks and enable users reaching ultimate centimeter level positioning accuracy.

The TS112 PRO also features NovAtel’s Glide smooth positioning that offers superior pass-to-pass accuracy down to 20 centimeters for applications where relative positioning is critical.

All models in the TS112 family support Harxon Slide technology to provide smooth positioning and exceptional linear accuracy so that the guiding system can continue to guide during satellite signal outages or in challenging environments.

The newly released family also support Harxon terrain compensation algorithm that is capable of correcting deviations that caused by vehicle’s roll and pitch while working on uneven grounds or slopes. It helps users increase operational efficiency and saving cost in the field.

Adopting ruggedized and IP67 standard housing, the TS112 family equip NMEA0183 and NMEA2000 CAN ports, RS-232 serial ports for easy connectivity.

News from the European Space Agency (ESA)

An ESA-supported project is testing autonomous vehicles on an intelligent road in Lapland, Finland.

Known as Snowbox, this 10-km stretch of forest-lined roadway on Finland’s E8 highway has been specially equipped for autonomous driving tests, ESA said. Containing cameras, “laser radar” lidar, ultra-wideband antennas and reflective panels, the road itself is underpinned by power and fibre optic lines, and embedded with pressure sensors to record road surface conditions and the speed and type of vehicles driving along it.

“If autonomous vehicles can drive well here, they can drive almost anywhere,” said Sarang Thombre of the Finnish Geospatial Research Institute, who’s managing the Arctic-PNT project. “Our project aimed at ensuring in particular that the precise positioning required by autonomous systems was available here, to establish this test site is indeed somewhere that driverless vehicle manufacturers should employ for testing. We carried out experiments with a robotic car over two successive seasons to show that the necessary precise positioning, down to 20 cm, is indeed accessible.”

Snowbox is also linked to the FinnRef network of satellite navigation reference stations, to deliver corrections for precise satnav positioning. By performing positioning measurements continuously at fixed locations, these reference stations serve as a standard, allowing the identification of measurement errors to boost positioning accuracy on a localized basis, ESA added.

“The Arctic is a difficult environment for autonomous driving in general,” Thombre said. “Signal disturbance due to the ionosphere, the electrically charged layer of the atmosphere, degrade satellite navigation performance. This effect is more pronounced in the Arctic region. And satnav augmentation systems also face challenges.

“Because their signals are broadcast from geostationary satellites, they are only viewable here at an elevation of up to 10 degrees above the horizon. And mobile coverage — useful for providing correction data from reference networks — is also inconsistent.

“In addition, possibility of mists and fog, snowstorms and rainfall make it difficult for cameras and lidar, while ice and snow on the road means wheel speed sensors may slip. And temperatures that can plunge down to below -30°C can impede the performance of electronics.”

The Arctic-PNT team’s testing was based around a robotic car crammed with sensors and recording equipment. Called Martti, the vehicle was supplied by Finland’s VTT Technical Research Centre.

“While Martti is capable of autonomous driving, we drove it manually,” Thombre said. “We were using it to capture all the data we needed. We started off using solely satellite navigation – including Europe’s Galileo and EGNOS – progressively adding more and more augmentation data, including in-car sensors, and corrections from the FinnRef stations, to reach the all-important precise positioning threshold of 20 cm.

“To access the FinnRef corrections from the car systems we tested out various mobile sim cards. Adding to the challenge, we crossed an international border, because part of the E8 highway is instrumented on the Norwegian side as well — called Borealis.”

The Snowbox infrastructure was established along the E8 because, while it is a remote roadway it is also economically important, with trucks heading south from Arctic fisheries.

The Arctic-PNT test campaigns, starting from 2018, gave a positive bill of health to the Snowbox, which is available for experiment campaigns. The campaigns were supported through ESA’s strategic initiatives for the Arctic region.

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Feature image: The Arctic-PNT team’s testing was based around a robotic car crammed with sensors and recording equipment. Called Martti, the vehicle was supplied by Finland’s VTT Technical Research Centre. (Photo: ESA)

Trimble has introduced the Trimble AX940 and AX940i high-precision GNSS smart antennas, designed for a broad range of high-precision applications such as precision agriculture, milling machines in construction, forestry harvesting equipment, autonomous vehicles, port automation and mobile mapping.

With multi-frequency, multi-constellation support for GPS, Galileo, GLONASS, BeiDou, QZSS and NavIC, the smart antennas can deliver reliable centimeter-level accuracy in a variety of environments. In addition, the Trimble AX940 and AX940i provide reliable, high-accuracy positioning without the constraints of a local base station or cell modem by using Trimble RTX correction services.

Built-in inertial sensors on the AX940i allow a tight integration with GNSS observations in the RTK/RTX positioning and orientation engine, providing continuous high-rate low-latency output to guidance and control systems.

“The new AX family of smart antennas delivers the latest GNSS and inertial technology in an easy-to-integrate and rugged form factor,” said Thomas Utzmeier, general manager for Trimble OEM GNSS. “Reliable, robust and compact, the smart antennas are an ideal option for OEMs and system integrators to easily and quickly add high-accuracy positioning to their applications.”

The Trimble AX940 and AX940i provide flexible interfaces with high-speed data transfer and configuration; simplified integrations reduce development times; and an intuitive 3D graphical web page allows easy input of the lever arm for easier set up.

The full-featured smart antennas are equipped with 336 channels for multi-constellation support; Trimble RTX and OmniSTAR support; flexible RS232, USB, CAN and Ethernet interfaces; and advanced RF spectrum monitoring. The AX940i also includes Wi-Fi and Bluetooth connectivity for wireless interface and control.

Using the latest Trimble Maxwell 7 Technology, the AX940 and AX940i are designed with flexible signal management that enables the use of all available GNSS constellations and signals.

The Trimble AX940 and AX940i smart antennas are expected to be available in the first quarter of 2021 through Trimble’s OEM GNSS Sales Channel.

After years of testing and hype, not a lot of companies can say there are real applications for autonomous technology. However, at this year’s virtual CES 2021 trade show, both Caterpillar and John Deere, two companies known for their tractors and heavy equipment, showcased autonomous machines that are being used worldwide in farming and mining projects.

Deerfield, Ill.-based Caterpillar, a first-time exhibitor at CES this year, said it has been involved in autonomy and use of GPS for more than two decades. “We were an early adopter of GPS when there were few satellites in the sky,” said Denise Johnson, company group president, resource industries. “We have 350 autonomous trucks operating 24-7 on three continents.”

The company’s autonomous vehicles, in addition to other technology, are being used around the clock in the Kearl Oil Sands project in Alberta, Canada.

“We are using autonomy primarily in mining operations in harsh environments. These [vehicles] are operating 24-7, with no loss time incidents,” said Bill Dears, Caterpillar worldwide sales and marketing manager. “We also track people underground with cameras and radar.”

In addition to production enhancement, safety is a factor in mining operations because of operator fatigue — something that is precluded by autonomous mining equipment, Dears said.

Agriculture uses variety of sensors, including GNSS

To Moline, Ill.-based John Deere, exhibiting at the trade show for the third time, agriculture is a high-tech industry that uses GPS, self-driving tractors, artificial intelligence and a multitude of sensors. The company rolled out its first self-driving tractors nearly 20 years ago, said Jahmy Hindman, John Deere CTO.

The company won the CES Innovation Award for one of its tractor and combine product lines. “Both our planter and tractor have GPS and antennas to know where to drive and where exactly fertilizer [is to be placed],” Hindman said. “These tractors are self-propelled, with accuracy augmented with [real-time kinematic] sub-inch accuracy for the planters in a field.”

Among other requirements, Hindman said that tractors have to drive in a straight line, plant the required amount seeds and position them at the right depth. “When a tractor drives in a very straight line, the burden is off of the farmer. The yields increase—this is the way we see the progression of automation,” he said. “We are excited about 5G and its lower latency and high bandwidth. It opens up a lot of opportunity.”

Organizers roll out Indy Autonomous Challenge race car

At the virtual CES, representatives from the Indy Autonomous Challenge unveiled the Dallara IL-15 race car that will be used in a head-to-head race around the famous Indianapolis Motor Speedway on Oct. 23.

The Indy Autonomous Challenge, organized by Energy Systems Network and Indianapolis Motor Speedway, pits 500 university students, developing autonomous vehicle technology, against each other for a $1.5 million prize.

Organizers say the speeds are estimated to be as much as 200 mph around the 2.5-mile track, for 20 laps, which enables researchers to evaluate how autonomous vehicle technology works in extreme conditions. They say that the goal of the race is to advance the implementation of autonomous vehicles and advanced driver-assistance systems (ADAS), much like the 2005 Defense Advanced Research Projects Agency (DARPA) Grand Challenge.

The race track has been the scene of much innovation throughout the years, said Doug Boles, Indianapolis Motor Speedway president. “Firestone tests tire technology there and that data transfers to our cars. One of the first conversations we had with Roger Penske [after Penske Entertainment bought the speedway] was about the autonomous challenge,” he said.

IAC sponsors include ADLINK, Ansys, Aptiv, AutonomouStuff, Bridgestone, CU-ICAR, Dallara, Indiana Economic Development Corp., Microsoft, New Eagle, PWR, RTI, Schaeffler and Valvoline.

Mobileye plans to test autonomous fleets in four cities

Intel subsidiary Mobileye plans to launch autonomous vehicle fleet testing in Detroit, Paris, Shanghai and Toyko. The announcement, made at CES by CEO Amnon Shashua, said that the company also plans to test in New York City, pending regulatory approval.

The company also plans to use in-house-built lidar sensors, while continuing to champion its camera-based testing. “We are using crowd-sourced data through the Cloud to build high-definition maps at scale,” Shashua said. “Thousands of product vehicles are sending us data.”

Shashua addressed a moderator’s question that cameras alone cannot be the technology of choice for autonomous vehicles. “The camera first is crucial from a technology and business point of view. We have to find out what is acceptable failure for Level 4 autonomy. Camera-only is ideal, but pushing the envelope for driver-assistance systems,” he said. “Consumer AV will take place in the 2025 timeframe. [Eventually], we can build lidar and radar to the same performance levels as camera systems. Lidar and radar can be added later for redundancy, but only for Level 4.”

Shashua said getting to Level 4 could take a decade, but that would be unsustainable unless there are government-funded projects to keep companies afloat. “By 2025, a subsystem will be good enough for consumers. Regulation is critical and sometimes it’s difficult to leap to a consumer level,” he said.

Not everyone believes what Mobileye is testing constitutes “driverless” status. To Alain Kornhauser Princeton University professor and transportation program director, who was head of the university’s team during the 2005 DARPA Challenge, not many companies are capable of full driverless capability.

“Unfortunately, I still see all of this as simply ‘eye candy’ to sell something that actually has no intention of delivering what it is implying. I still claim that the business case is zero, doesn’t exist, for personally-owned autonomous vehicles,” Kornhauser said in his Smart Driving Cars weekly newsletter. “Mobileye is nowhere close to being able to operate safely on most roads, let alone all roads. Thus, the consumer market has zero opportunity to scale.”

Kornhauser said that driverless testing is being conducted only in one place, Phoenix, by Waymo. “Neither Tesla nor Mobileye are driverless anywhere. They both require on-board human driver supervision,” he said. “That’s why they are only self-driving [tests].”

In other CES news:

• GM CEO Mary Barra unveiled a single-seat electric vertical takeoff and landing (eVTOL) concept aircraft. The aircraft will be developed for future use as an air taxi. Barra briefly mentioned that the company’s Super Cruise self-driving technology will be integrated into 22 car models in a few years. The company also rolled out an electric vehicle for deliveries that can travel 250 miles on a charge and a motorized pallet for deliveries that can be tracked.
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  Photo: Mercedes-Benz

  The Mercedes-Benz’ MBUX Hyperscreen, rolled out at CES, evaluates map data, surroundings and provides information about landmarks along a route, said Sajjad Khan, company CTO and member of the board of management. The new map feature, called Mercedes Travel Knowledge, allows a passenger or driver to ask a question as they drive by a landmark (“hey, Mercedes, what can you tell me about this building?”). The MBUX Hyperscreen is available in the new S-Class cars.

• HERE Technologies introduced a mapping-as-a-service platform at CES. The platform is targeted to businesses wanting to create custom map datasets for advanced analytics and services, the company said. Some use cases include industrial yard mapping, leveraging probe data from private vehicle fleets in order to create or update a map.• A virtual CES is hard to get used to. After more than 20 years of covering the massive trade show in person, covering press conferences and conducting interviews online was sometimes a challenge. Sometimes the press conferences did not have question-and-answer sessions, or canned answers given to executives by public relations people. This doesn’t happen much during an in-person interview. In addition, trying to chat with “booth” personnel online was cumbersome and often those requests for information were ignored.

In a report issued on Jan. 14, the Department of Transportation (DOT) outlined the results of its GPS Backup Technology Demonstration project. As officials had previously projected, it called for a system-of-systems approach using multiple complementary technologies.

The report called for an architecture that included signals from space in the L-band, terrestrial broadcasts in the ultra high frequency (UHF) and low frequency (LF) spectra, and a fiber backbone to synchronize and feed precise time to terrestrial transmitters.

The demonstration project and report were mandated by Congress in legislation passed in late 2017 and funded in early 2018. Delays within the administration resulted in the project beginning in early 2019.

Demonstrations

Of 21 firms that offered to demonstrate their wares, 11 were selected. They were:

• Echo Ridge LLC and Satelles Inc. Satellite-based PNT technologies using the S and L bands, respectively.
• OPNT B.V. and Seven Solutions S.L. Fiber-optic time transfer using the White Rabbit Precision Time Protocol technology.
• TRX Systems Inc. Dead reckoning technology with inertial measurement units and localized map matching supplemented with ultra-wideband beacons.
• Hellen Systems LLC and UrsaNav. eLoran that uses LF transmissions.
• Serco Inc. Medium frequency R-mode.
• NextNav LLC. Metropolitan beacon system using UHF frequencies.
• PhasorLab Inc. and Skyhook Wireless Inc. Both use Wi-Fi frequencies. Phasorlab uses a dedicated network of transmitters. Skyhook leverages existing Wi-Fi access points.

Five of the demonstrations were conducted at Joint Base Cape Cod, with the remainder at NASA’s Langley Research Center in Virginia.

Timing demonstrations were assessed for system:

• coverage (service availability) within an “appropriate area” (wireless systems only)
• accuracy and stability across an appropriate area
• long-term accuracy and stability of time transfer to a fixed location
• time transfer availability and accuracy to a fixed location under challenged GPS signal conditions.

Positioning was evaluated for:

• coverage within a defined region
• 2D and 3D dynamic positioning service availability and accuracy
• availability and accuracy of static positioning
• long-term availability and accuracy of static positioning
• long-term availability and accuracy of static positioning under challenged GPS signal conditions

DHS work referenced

The report also mentions an earlier set of demonstrations done by the Department of Homeland Security (DHS).

In December 2018, DHS’s Science and Technology Directorate performed the work through the Homeland Security Systems Engineering and Development Institute. The project “demonstrated a combination of position and timing use cases for dynamic vs. static and indoor vs. outdoor applications, along with a time-transfer use case for critical infrastructure applications.” Systems from Locata Corp, NextNav, and Satelles were evaluated.

The DoT report says that eLoran was not part of the DHS effort because of the lack of transmitters in the area. However, “DHS had previously studied eLoran performance under a Cooperative Research and Development Agreement (CRADA) with Harris Corporation and UrsaNav and had an understanding of its capabilities.”

A report of DHS’ December 2018 work is not publicly available, though DOT says it was used to inform their efforts.

The only publicly available information from DHS about the eLoran CRADA seems to be a 2016 press release. A presentation and other information  is available on the UrsaNav website.

Findings

The 437-page DOT report is filled to the brim with detailed information about the project, individual technologies, and demonstration results.

The Executive Summary says that, in addition to the findings from the DHS December 2018 effort (which were not listed), the DOT demonstration had four key findings:

1. All TRL-qualified vendors offered showed PNT “performance of value” and one showed value in all scenarios.
2. Neither eLoran company succeeded in the Static Basement Timing scenario.
3. R-mode ranging did not meet the minimum technical readiness level (TRL) of 6.
4. Deployment effort and coverage (infrastructure per unit area) are significant cost factors.

Addressing the needs of critical infrastructure owners and operators, the report concluded the needed “technologies are LF and UHF terrestrial and L-band satellite broadcasts for PNT functions with supporting fiber optic time services to transmitters/control segments.”

Reactions and way forward

Government officials and industry observers alike have welcomed the report, though it does leave some questions on the table.

One is about other national PNT needs. The congressional tasking was to report on GPS backup technologies for critical infrastructure and national security. The Jan. 14 report focuses on critical infrastructure needs. Information on national security requirements, some of which is classified, was provided to Congress separately by DHS and the Department of Defense.

“Economic and homeland security are sometimes considered by agencies and Congress as subsets of national security, sometimes not,” according to one analyst. “So, we don’t know if the needs of first responders, delivery services, civil government agencies, and other essential users were ever formally considered. The good news is that the combination of systems identified, if implemented and made available to all, would likely meet the needs of most.”

Other open issues are about implementing the report’s recommendations.

Some have been quick to point out that the demonstrations were to inform the government, not part of a procurement.

“If this was for an acquisition, it would have been done differently,” said one government retiree.  “Rather than having vendors set up and operate the equipment, government evaluators would have been much more hands on. And they would have made every effort to do all the trials at the same location.”

Going forward, cost will also an important factor, as mentioned in the report’s key findings. “Depending on who you want to serve and where, the costs of different technologies vary by orders of magnitude,” said one provider.

Reaction from those involved with the demonstration project has been generally upbeat with praise for DOT’s effort and anticipation of more progress.

Typical were comments from Ganesh Pattabiraman, CEO at NextNav, who appreciated the real-world scenarios DOT used in the project. Regarding next steps he said, “We look forward to working with Congress on implementing the report’s recommendations.”

NASA’s Space Communications and Navigation (SCaN) program is developing capabilities that will allow missions at high altitudes to take advantage of GNSS signals for timing and navigation, including the Artemis missions to the Moon.

Interoperability of the GNSS constellations will be key for spacecraft at higher altitudes where GNSS signals are less plentiful. The program will rely on the four global constellations (GPS, Galileo, GLONASS and BeiDou) and the two regional systems operated by India and Japan.

SCaN is supporting flight experiments that will help develop multi-GNSS capabilities for spacecraft, such as Bobcat-1, developed by NASA’s Glenn Research Center in Cleveland and Ohio University.

Bobcat on the Prowl

Bobcat-1 was selected by the CubeSat Launch Initiative in 2018 to study GNSS signals from 250 miles overhead. The small satellite launched to the International Space Station aboard a Northrop Grumman Cygnus spacecraft on Oct. 2, 2020.

On Nov. 5, the space station released the CubeSat to begin its mission. The spacecraft will orbit for about nine months, measuring signals from different GNSS constellations. Engineers will use these measurements to better understand GNSS performance, specifically focusing on timekeeping variations between the constellations.

“GNSS users at high altitudes see fewer satellites,” said Bobcat Co-Principal Investigator Frank Van Grass of Ohio University. “Time offsets between the constellations can be measured by the CubeSat and provided to these users to improve their positioning performance,”

SCaN Testbed

Bobcat-1 builds on the legacy of the SCaN Testbed, which demonstrated multi-GNSS capabilities on the space station from 2012 to 2019. The GPS and Galileo Receiver for the International Space Station (GARISS) — an instrument developed in collaboration between NASA and ESA (European Space Agency) — received signals from both GPS and Galileo, the GNSS constellation operated by the European Union.

The SCaN TestBed also laid the foundation for the Lunar GNSS Receiver Experiment (LuGRE), a Commercial Lunar Payload Services payload being developed in partnership with the Italian Space Agency. The payload will receive signals from both GPS and Galileo and is expected to obtain the first-ever GNSS fix on the lunar surface.

GNSS PNT Policy and Advocacy

While NASA engineers develop the technologies necessary for multi-GNSS navigation at ever-higher altitudes, the SCaN team works with stakeholders in the U.S. government and internationally to advance GNSS interoperability in the policy sphere. They consult on the United Nations International Committee on GNSS, helping develop additional capabilities in the Space Service Volume and beyond.

NASA recently worked to publish GPS antenna patterns from GPS satellites that launched between 1997 and 2000, collaborating with the U.S. Space Force, the U.S. Coast Guard and Lockheed Martin, who built the satellites. The PNT team is also working to facilitate publication of antenna patterns for more recent GPS satellites.

With this data, mission planners can better assess the performance of GNSS in high-Earth orbit and lunar space. This forthrightness also encourages other GNSS providers to be similarly transparent.

“GNSS capabilities continue to revolutionize the ways spacecraft navigate in near-Earth space and beyond,” said NASA navigation engineer Joel Parker. “NASA’s longstanding relationships with the GNSS providers have advanced these capabilities to new heights and support the Artemis missions on and around the Moon.”