> The US military is working on a device that can use stars to determine location even during the day.
They already developed a device that could do that in the 60s, but it was quite large:
https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Astro...
https://timeandnavigation.si.edu/multimedia-asset/nortronics...
Do you have a source for the one you say they're working on? Is more portable or hand-held?