The Global Positioning System involves the use of transmission of at least 4 radio wave signals from a "constellation" of 24 earth-orbiting satellites at one time. A Global Positioning System (GPS) unit consists of a space segment, a control segment, and a user segment. The space segment is a constellation of two-dozen satellites orbiting the earth twice every 24 hours, at approximately 10,900 nautical miles above the earth's surface. The control segment is a series of monitoring stations located …showed first 75 words of 673 total…

…showed last 75 words of 673 total…clocks cost somewhere between $50 000 and $100 000, far too expensive for ordinary consumer use. So the Global Positioning System has a clever and effective solution to this problem. Every satellite contains an expensive atomic clock, but the receiver itself uses an ordinary quartz clock, which it constantly resets. Bibliography http://www.soi.city.ac.uk/~dk708/pg3_3.htm www.digitalangel.net www.howstuffworks.com (Brain M. How a GPS Receiver Works.) http://www.geocan.nrcan.gc.ca/