Yes, I'm very curious too what mod you are talking about. Or are you talking about radio messages stating latitude and longitude where they are. If so, then you can ignore them since they are not real. You just receive them to cut the boredom.
As for how to find lattitude longitude coordinates (just so you know, back in the WW1/2 days there were no such things as GPS satelites. They used sextants to measure positions of things called stars and planets and moon.
)... There are black/white bands on the edge of the map that are certain intervals of degrees. Or you can measure distances away from the equator and Greenwich meridian, 1 degree is 120km.