Key points are not available for this paper at this time.
A brief history of navigation is given, highlighting the needs that led ultimately to the development of 3-D satellite based navigation. The evolution of Navstar, commonly known as GPS (Global Positioning System), is traced from its initial conception in 1960. The use of bandwidth compression to overcome the SNR problem is discussed. An explanation of how the GPS works is provided. Civilian as well as military applications are examined.>
Ivan A. Getting (Wed,) studied this question.