Submarines do not have to surface to get a GPS lock. https://en.wikipedia.org/wiki/Submarine_navigation https://en.wikipedia.org/wiki/Submarine_navigation "On

Submarines do not have to surface to get a GPS lock. https://en.wikipedia.org/wiki/Submarine_navigation https://en.wikipedia.org/wiki/Submarine_navigation "On the surface or at periscope depth, submarines have used these methods to fix their position"...GPS being one of them. A submarine can also navigate by the stars without surfacing. https://www.usni.org/magazines/proceedings/2021/october/navigate-stars-beneath-waves https://www.usni.org/magazines/proceedings/2021/october/navi... "This is precisely the information required by the traditional method of celestial navigation, and it is accomplished without the need to surface or use a sextant!"