Global Positioning Satellites
| Scientific Paper | |
|---|---|
| Title | Global Positioning Satellites |
| Author(s) | Howard C Hayden |
| Keywords | GPS, satellites, signals |
| Published | 1994 |
| Journal | Galilean Electrodynamics |
| Volume | 5 |
| Number | 4 |
| Pages | 92-82 |
Abstract
The global positioning satellite (GPS) system is a marvelous invention for enabling an observer anywhere on earth to measure his location with great precision. Timing by extremely precise atomic clocks on the satellites, and exact knowledge of the orbits are the keys to the precision. The presence of at least four satellites well above the horizon at any given time and location enables the ground-based observers to use clocks of considerably lower precision than those on the satellites. A pseudo-random code used in the communication system allows the observer to use portable equipment, even though the signals are extremely weak.