India joins an elite club, one of 5 countries to use Rubidium Atomic Clock in their GPS satellite
Indias ISRO joins an elite club of space agencies which use a very complex and technical device, a Rubidium atomic clock in their GPS satellites. Only 4 other national space agencies use this atomic clock - USAs NASA, EUs ESA, Chinas CNSA and Russias ROSCOSMOS.
United States Space Applications Centre European Space Agency Rubidium Atomic Clock Rubidium Atomic Atomic Clocks
Source: firstpost.com