A brief history of positioning
Global Navigation Satellite Systems

The North Star as a guide

Without going back to the earliest traces of navigation, the first technique used on a large scale was to measure the height of the North Star above the horizon. As it happens, this measurement gives a good idea of the latitude of the place of observation. It was this technique that enabled Christopher Columbus to aim for relatively close destinations on his various voyages. At the time, the navigation technique was based on sailing North or South towards the destination latitude, then East or West. Christopher Columbus was aiming for India at a latitude of around 10° North, hence his various destinations.

There is no comparable star in the southern hemisphere....