In this interactive activity produced for Teachers' Domain, learn how the Global Positioning System (GPS) uses trilateration to identify the location of a receiver. Investigate how each GPS satellite broadcasts a radio signal that carries information (the time the signal was transmitted, the position of the satellite, and a pseudo-random-noise code) and how the signals from three different satellites are used to determine the receiver's location. In addition, explore how the signal from a fourth satellite is used to achieve greater precision.
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