Two for One
TWO FOR ONE
The GPS system was originally developed for use by the military and government agencies, but the U.S. government has made it available for commercial use. The first nongovernment users were surveyors and commercial trucking and seagoing shipping firms. Today, with GPS receivers becoming increasingly affordable, their use has expanded to the general public, allowing recreational boaters, hikers, even people just driving their cars, to determine their location via satellite. This dual-purpose role is supported through the use of two different GPS services levels. The Standard Positioning Service (SPS) is available to nongovernment users, while military and federal government users utilize the more accurate Precise Positioning Service.
"Two for One." Space Sciences. . Encyclopedia.com. (November 18, 2018). https://www.encyclopedia.com/science/news-wires-white-papers-and-books/two-one
"Two for One." Space Sciences. . Retrieved November 18, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/news-wires-white-papers-and-books/two-one