A Concept for Navigation and Communication using Satellites

Extract

Of all man-made objects, satellites are unique in their ability to ‘see’ large regions of the Earth at one time. Because of this ability, they can serve as relays to provide the advantages of line-of-sight communications between widely separated points on the Earth. They have another useful characteristic also—their locations in space can be determined to high accuracy, hence they can be used as position references for navigation or surveying.