GPS ;

Global Positioning System (GPS) refers to the NAVSTAR Global Positioning System, a constellations of satellites developed by the United States Department of Defence. At first the GPS was made for military use only, but later made accessible to civilians as well. But recently, GPS is most widely used GNSS satellite constellation in the world.

GLONASS ;

Globalnaya Navigazionnaya Sputnikovaya Sistema (GLONASS) is an acronym which is translated from Russian, this means Global Navigation Satellite System. It is accessible for both military and civil use and also provides real time position and velocity determination.

The main difference between GPS & GLONASS is that, with GPS satellites use the same radio frequencies but have different codes for communication while GLONASS satellites have the same codes but use different frequencies, allowing satellites on the same orbital plane to communicate.