On April 8, 2020, the U.S. Department of Homeland Security submitted a report on alternative sources of PNT to U.S. congressional committee leaders. The Report on Positioning, Navigation, and Timing (PNT) Backup and Complementary Capabilities to the Global Positioning System (GPS) was subsequently released to the public on May 6, 2020.
The DHS report highlights the urgent need for GPS backup for critical applications, and it identifies and characterizes a variety of solutions that are available to meet this need today. The report also describes the essential role of the Federal Government in urging industry to implement multiple technologies instead of endorsing or investing in a single solution to back up GPS.
Satelles issued an in-depth position statement about the report on May 12, 2020, but here are a few key highlights:
Diverse needs of critical instructure sectors and the common requirements between them are both met by alternative forms of PNT.
Each critical infrastructure sector has different needs, but there are certain baseline requirements. Satelles believes that a heterogeneous backup to GPS is in the public interest and also agrees with the report’s statement that “DHS could not identify generic specifications for a national backup” because “[t]he position and navigation functions in critical infrastructure are so diverse that no single PNT system, including GPS, can fulfill all user requirements and applications.”
In calling out some common specifications, DHS explains that “a minimal acceptable precision of anywhere between 65-240 nanoseconds […] supports all critical infrastructure requirements.” The report states that this range “is expected to meet future requirements, including 5G.” Based on the precision of timing references used by receivers, STL currently delivers timing accuracies between 50 to 240 nanoseconds, proving that it is one of the out-of-domain solutions ready to meet timing requirements that strengthen the resilience of critical infrastructure.
Critical infrastructure owners and operators need more than a single form of alternative PNT.
The Federal Government should neither provide nor select a single PNT solution; rather, it should encourage diversity and invest in multiple technologies. With regard to any kind of government preference for a particular PNT system, DHS states that “the government would have to consider the repercussions of such a system in the marketplace” because “[a] free government system would negatively impact commercially available PNT systems by directly competing with them.”
Satelles maintains the view that a truly resilient and globally available GPS backup capability is only possible with an open, technology-neutral approach that encourages diversity. Furthermore, Satelles agrees with DHS that “[t]he Federal Government should encourage adoption of multiple PNT sources [by] critical infrastructure owners and operators [and] focus on facilitating the availability and adoption of PNT sources in the open market.”