|
|
|||||||||||||||||||||||||||||||||
| Definitions | Initials | To take part | Leading Team | Directory |
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Definitions
Directory
Dictionary > Definitions > Sciences > GPS
GPS
Definition
The GPS (Total Positioning System) is a system of navigation per very precise satellite.
Description
System GPS was conceived at the origin with fine soldiers by American. Marketed from the very start of the years 1990, its principle is relatively simple: Several satellites of systems of navigation emit uninterrupted coded signals (the satellites are the transmitters). These signals are received by a receiver (the GPS which you bought in the trade) which calculates the hour to which the signal was emitted. By calculation of the duration put by the signal to arrive of the transmitter to the receiver, one obtains a pseudo distance (the electromagnetic waves are propagated at the speed of the light). Pseudo distance because it contains error of an unknown but single synchronization when measurements of pseudo distances are simultaneous, i.e. when the signal of emission of the various satellites are simultaneous. Thus with the data resulting from several satellites located at different places, one obtains several values (four in general), which make it possible to determine 3 unknown factors and a constant error. These three unknown factors are the lattitude, longitude and altitude. System GPS is in fact made up of more than 24 satellites (in order to be able to obtain 4 pseudo-measurements whatever the place or one is on the terrestrial sphere), orbits about it around the ground. To distort the measurements given by a GPS, it is enough to desynchronize the signal of emission of the various satellites. This practice would have been used by the various armies at the time of the recent conflicts. The GPS thus tends to replace another system of measurement of the position used in the navy: the marine sextant.
Author
Anwar Hossain
Author Email
anwtele@yahoo.com
References
Definitions to be consulted