Not just supporting players, alternative positioning, navigation and timing (PNT) systems strengthen, augment and — when needed — replace GNSS. We explore how companies are using alternative PNT, and talk with John Fischer of Orolia and Alexis Guinamard of SBG Systems about their companies’ latest developments.
Since the 1990s, GPS has provided the United States military with a substantial tactical edge. Civilian GPS applications are now deeply embedded in every aspect of our lives. The U.S. Department of Transportation recently reaffirmed that GPS’ positioning, navigation, and timing (PNT) services are critical to the safe and efficient use of the national transportation system, and a Feb. 12 presidential executive order declared that satellite-based PNT services “have become a largely invisible utility for technology and infrastructure.”
It has long been equally well known, however, that GPS is vulnerable to accidental and intentional interference (the latter known as jamming), spoofing, and degradation or denial of signals. Additionally, GPS satellites are increasingly vulnerable to damage or destruction by space debris or intentional attack. The executive order mentioned above declared it U.S. policy “to ensure that disruption or manipulation of PNT services does not undermine the reliable and efficient functioning of [the country’s] critical infrastructure.”
Protecting PNT requires not just strengthening GPS, but also developing alternative sources of PNT data and ways to integrate them into the myriad systems that currently rely on GPS.
The National Timing Resilience and Security Act of 2018 (passed by the U.S. Senate as part of that year’s Coast Guard authorization act), called for “a complement to and backup for” the GPS timing component “to ensure the availability of uncorrupted and non-degraded timing signals for military and civilian users in the event that GPS timing signals are corrupted, degraded, unreliable or otherwise unavailable.” It mandated the procurement of a wireless, terrestrial system that would provide wide-area coverage and be synchronized with UTC, resilient and extremely difficult to disrupt or degrade, able to penetrate underground and inside buildings, and capable of deployment to remote locations.
A report released on April 8 by the Department of Homeland Security (DHS), however, recommends “that responsibility for mitigating temporary GPS outages be the responsibility of the individual user and not the responsibility of the federal government.” It points out that research by one of DHS’ agencies “shows that users can mitigate short-term GPS disruptions (e.g., inability to read a GPS signal) with various strategies, ranging from using local backup capabilities to delaying operations until GPS is restored.” The report then focuses on “mitigation against long-term or permanent disruption or loss of GPS PNT capabilities.” It determines that the PNT functions in critical infrastructure “are so diverse that no single PNT system, including GPS, can fulfill all user requirements and applications” and notes that maximum resilience is found in diversity of solutions. Therefore, it recommends that the federal government “encourage adoption of multiple PNT sources [to expand] the availability of PNT services based on market drivers.”
In the interviews below, I discussed these challenges with John Fischer, vice president of Advanced R&D at Orolia, and Alexis Guinamard, chief technical officer of SBG Systems.
• How Orolia is taking resilient PNT to the next level
• Software joins hardware at SBG Systems for alternative PNT
Check out how these companies are using alternative PNT to strengthen, augment and — when needed — replace GNSS.
• Parker LORD launches all-in-one RTK system
• NovAtel SPAN prepares for road ahead
• OxTS board set ready for system integrators
• NASA’s Orion travels with Honeywell, Lockheed Martin
• SimINERTIAL designed for GPS/INS testing
• Inertial Labs releases 2-axis, 3-axis gyroscopes
Featured image: NovAtel