Publisher's Note Now in its fourth edition, this best-selling book explains recent advances in the technology of Global Positioning System and shows how GPS works and how it can be used for precise measurements (i.e. surveying) as well as for navigation and attitude determination. The practical use of GPS is explained in detail, as well as the basic mathematical models for various modes of GPS operation, with examples of different applications and types of projects. Proper project planning, execution, data reduction and coordinate computation are also explained for novice GPS users.