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Trilateration

Trilateration is a method for determining the intersections of three sphere surfaces given the centers and radii of the three spheres. Trilateration is used by GPS devices to compute exact location based on signals received from a satellite and the time that signal takes to get from the satellite to the receiver. A mathematical derivation for the solution of a three-dimensional trilateration problem can be found by taking the formulae for three spheres and setting them equal to each other. To simplify the calculations, we apply three constraints to the centers of these spheres; we assume all three spheres are centered on the z=0 plane, one is at the origin, and one other is on the x-axis. It is possible to transform any set of three points to comply with these constraints, find the solution point, and then reverse the translation to find the solution point in the original coordinate system. ... more

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System Design Strategies

System Design Strategies is an exclusive resource for the successful design and deployment for geographic information systems technology. This documentation is provided to share system architecture design methodology and the fundamental principles that contribute to system performance and scalability.

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In 1119 this geographer edited an updated the Geographica, a geographic encyclopedia first created in the eighth century.