GPS World

Tag: DOT report

  • Senate proposes $15M to develop GPS alternatives

    Senate proposes $15M to develop GPS alternatives

    This week Sen. Patrick Leahy (D-Vt.), chair of the Senate Appropriations Committee, released that body’s version of nine different appropriations bills. The accompanying report for the bill to fund the Transportation Department (DOT) outlines the Senate’s intentions and way forward for establishing alternatives to GPS.

    The report provides $15 million for the fiscal year that began on the first of October “to establish a program that leads to wide adoption of multiple technologies that provide the necessary GPS backup and complementary PNT as identified by the Department’s report.”

    The department report referenced was on a demonstration project that examined GPS backup and complementary technologies from 11 different vendors. That DOT report found, based on the technologies demonstrated, a combination of signals delivered from space, terrestrial low frequency (LF) and ultra-high frequency (UHF) broadcasts, and fiber would best meet the nation’s needs.

    The Senate report accompanying the funding bill outlines components of the GPS alternatives program, including:

    • development of safety-critical PNT requirements and standards,
    • user adoption models to facilitate responsible use of resilient PNT, and
    • procurement of services deemed appropriate by the department.

    The Senate Committee report can be found here. Relevant provisions are on page 12.

    Services Contracts

    While not setting a deadline for issuance of a Request for Proposal, the mention of procuring services is seen by many as a strong indication that Congress expects more than just additional studies.

    Services contracts, as opposed to the government building its own system, have long been advocated by numerous members of industry and by the Resilient Navigation and Timing Foundation. Contracting for services with commercial providers is a better model, they have argued, as the needed technologies are mature and commercially available. Also, issuing one or more services contracts would avoid the need for the huge funding lines and lengthy delays inherent in a government major systems acquisition.

    Many have suggested that services contracts would also be a much more economical approach for the government. They say commercial interests can operate their systems more efficiently, and that they could offer additional services to other customers, potentially reducing costs to the government.

    ADS-B Sets Example

    Such an approach was used by the Federal Aviation Administration (FAA) for the ADS-B air traffic safety and management system. The FAA needed to monitor and use signals from ADS-B equipment aboard a wide variety of aircraft flying in U.S. airspace. Rather than building a nation-wide ground infrastructure, the FAA issued a long-term service contract for a company to collect and provide the signals. The awardee, Exelis (now L3Harris), won the contract, built the infrastructure, and now provides ADS-B information to the FAA and others on a subscription basis.

    Most observers expect the portions of the Senate bill and report about the GPS alternatives program to be adopted in conference with the House and then enacted into law.

    How far the Department of Transportation will be able to develop the program this fiscal year remains to be seen. The Senate provisions do require DOT to report on its progress in a year’s time. Earlier informal reports and updates to the committee are likely to inform funding and other legislation on this effort for fiscal year 2023.

    Dana A. Goward is President of the Resilient Navigation and Timing Foundation

  • NextNav, Satelles collaborate on Bay Area alternative PNT testbed

    NextNav, Satelles collaborate on Bay Area alternative PNT testbed

    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.

    Image: imaginima/iStock / Getty Images Plus
    Image: imaginima/iStock/Getty Images Plus/Getty Images
  • DOT report: L-band, UHF, LF and fiber PNT needed to protect US

    DOT report: L-band, UHF, LF and fiber PNT needed to protect US

    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.

    Monty Johnson of OPNT demonstrates precise time transfer through 100 kilometers of spooled fiber-optic cable. (Photo: RNT Foundation)
    Monty Johnson of OPNT demonstrates precise time transfer through 100 kilometers of spooled fiber-optic cable. (Photo: RNT Foundation)

    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.”