>> Military solutions will fall back to inertial, celestial or optical guidance, and people using GPS for navigation will at worst show up where they need to be

>> Military solutions will fall back to inertial, celestial or optical guidance, and people using GPS for navigation will at worst show up where they need to be somewhat later than planned. > The US Navy re-started celestial navigation a few years ago: Also, the SR-71, B-1, and B-2 and other aircraft have automated celestial navigation systems to provide corrections to their INSs: https://www.thedrive.com/the-war-zone/17207/sr-71s-r2-d2-could-be-the-key-to-winning-future-fights-in-gps-denied-environments https://www.thedrive.com/the-war-zone/17207/sr-71s-r2-d2-cou... Honestly, for military applications, GPS seems to be mainly useful for bad weather and providing navigation to the smallest units (and I'd think a small unit would be able fall back to a map and compass).