GPS Made Easy: Using Global Positioning Systems in the Outdoors

A non-technical guide to using handheld GPS receivers outdoors. It was revised after the U.S. government turned off Selective Availability in May 2000. That change alone improved unaided civilian accuracy from roughly 100 meters to under 10.

The book explains how the GPS satellite constellation and signal work. It surveys the features common to handheld receivers of the period. And it works through practical field examples: setting waypoints, plotting routes, and using a receiver alongside a paper topographic map in rough or featureless terrain. This third edition, marketed as "SA Revised," added material on the first two editions covering GPS with maps for hiking, kayaking, and other backcountry travel.

Lawrence Letham is an electrical engineer by training. He wrote the book for the hikers, campers, and outdoor navigators he counted himself among. GPS Made Easy went through five editions between the mid-1990s and 2008, tracking each new generation of consumer GPS technology from the pre-SA era through WAAS-corrected receivers.