Charla,
US submarines were using an early form of GPS in the mid 70's. It was called NAVSAT. We were using it on Barbel in 1974. I don't remember what antenna we used for signal reception though. When I was working as a civilian employee for the US Navy in mid 80's at Holy Loch Scotland, I was invited to tour USS Andrew Jackson (SSBN-619) by the blue crew skipper because I was blue commisioning crew member on her in 1963. At the time of the tour (1986) they no longer had a type 11 periscope. The significance of this is that the type 11 was used only for star shots as a way to cross check SINS accuracy. So I assume they were using NAVSAT as their SINS crosscheck.

Some more submarine trivia for you.... When I was on the Cusk (SS-348) in 1961, we had a device called SCAR (Sperry Celestial Altitude Recorder) that allowed you to shoot a sun-line through number 1 periscope (observation scope). I know it was not very accurate, and the navigator and Quartermasters thought it was a lot of trouble to use for such poor results.