The Frank LoBiondo Coast Guard Authorization Act of 2018 had with-in it the provision National Timing Resilience and Security Act of 2018:

* https://rntfnd.org/wp-content/uploads/National-Timing-Resili...

A roadmap was published in 2021:

* https://www.transportation.gov/pnt/national-timing-resilienc...

And also from 2021, NATIONAL R&D PLAN FOR POSITIONING, NAVIGATION, AND TIMING RESILIENCE:

* https://bidenwhitehouse.archives.gov/wp-content/uploads/2021...

The simplest solution is to simply to resurrect the Loran infrastructure that the US (and others) run until the 2000s. The Koreans have been running eLoran for a while, and the UK and France are teaming up as well:

* https://insidegnss.com/uk-and-france-renew-ties-resilient-pn...

* https://rntfnd.org/2025/11/12/s-korea-leads-meeting-with-u-k...

Chinas has had a completely built out network (including fibre networks for high-precision timing) for over a year:

* https://rntfnd.org/2024/10/03/china-completes-national-elora...

This is not rocket surgery: a working system that can giver you continent-wide coverage can be up and running a few years, with little technical risk (there's already kit available).

Throwing some money at the problem and instructing the DOT/DHS/whomever to issue an RFI/RFP would go a long way to moving the ball forward.