GPS (Global Positioning System) and other Global Positioning Systems

Date: 19/11/2022 Author: Antonio H.

GPS (Global Positioning System) Global Positioning System

It is a system that allows to locate an object that is on Earth with high precision. To do this, the receiving device locates at least four satellites from the satellite network placed in orbit, from which it receives signals that indicate the identification and the time of the internal clock of each satellite. With this information the distance to the satellite is calculated. Knowing the distance to these satellites and by the "trilateration" method, the GPS device can determine the position on the Earth's surface.

With three satellites, the device is capable of determining the latitude and longitude of its position, that is, its position in two dimensions. By adding a fourth satellite, it will also be able to calculate the altitude, obtaining the position in three dimensions. The signals emitted by each satellite form a sphere with the satellite in the center, the point of intersection of all the spheres is what determines the position where the GPS receiver device is located.

Satelites GPS

Satellite 2D

 

As a curiosity, the satellites transmit on three different frequencies of the radio frequency L band (1000 – 2000 MHz) of the electromagnetic spectrum.

 

 

Other Global Positioning Systems There are currently four major global positioning systems:

 

GPS : The best known and currently used is GPS, which is a system owned by the United States Department of Defense and consists of three parts: orbiting satellites, base stations and receivers. Its coverage extends to the whole world. Its real name is NAVSTAR (Navigation Satellite Timing and Ranging).


GLONASS (GLobalnaya NAvigatsionnaya Sputnikovaya System): It is Russia's state-owned positioning system and also has worldwide coverage.


Galileo : Galileo has been developed by the EU as an alternative to GPS and GLONASS.


BeiDou : It is the system created by China and has worldwide coverage although it offers greater precision in Asia and the Pacific. BeiDou means Big Dipper in Chinese.


There are also other systems, although their coverage is only regional, such as the NavIC system in India or the QZSS system in Japan.