For the SatNav user who wants to know more about how GPS, navigation and mapping combine together to give us these systems. It is intended as a behind the scenes information and awareness for those with an interest in understanding more about what is involved, the difficulties encountered and some misconceptions that are around. It is not a guide to particular systems or how to use them individually. It will not directly help you to not get lost. It will help you to understand where things can go wrong, how to notice them and correct them, or at least to know not to rely on it for the moment.
Topics covered are
What GPS consists of and how it works to give a position, methods of increasing accuracy and what accuracy means.
Methods of projecting the round world onto flat, your satnav screen, and how datums are used to produce coordinate systems.
Digital maps, map structures and databases and how the system works out route navigation.
It is a reasonably technical subject but explanations are made easy, in ways not done by many conventional methods, and backed up by diagrams. Some of the technical involves horrible sums. These are included for greater awareness but are firmly hidden in appendices as an option for the daring.