I saw some rumblings (can't find an article) that there's interest in restarting LORAN to provide an alternative to GPS for this reason.
eLoran has been proposed as more accurate version of LORAN competitive with GPS.
The Wikipedia page says that China has deployed an eLoran network but I can't tell if used for navigation or just high-precision timing.
See UK and France:
* https://insidegnss.com/uk-and-france-renew-ties-resilient-pn...
LORAN can be jammed.
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eLoran has been proposed as more accurate version of LORAN competitive with GPS.
The Wikipedia page says that China has deployed an eLoran network but I can't tell if used for navigation or just high-precision timing.