Global positioning system - GPS - is a huge advance in navigation. Highly accurate map capable units can be purchased at reasonable prices and are readily available just about everywhere.

The Global Positioning System is a network of satellites in different orbital paths. A GPS unit establishes contact with at least three of these satellites and uses the information received to determine altitude, longitude, and latitude. The unit takes measurements constantly and plots your path on a map (for mapping enabled GPS units), and also provides a digital display of relevant information. In order to calculate altitude, the unit must have access to at least four satellites. There are no fees or setup charges to use GPS.