Global Positioning System (GPS) – UPSC GS3

Explain the working principle behind the Global Positioning System (GPS). Write a note on the efforts made by India to create its own GPS system. (200 Words)

The Global Positioning System (GPS) is a satellite-based navigation system that consists of 24 orbiting satellites, each of which makes two circuits around the Earth every 24 hours. These satellites transmit three bits of information – the satellite’s number, its position in space, and the time the information is sent. These signals are picked up by the GPS receiver, which uses this information to calculate the distance between it and the GPS satellites.
Working & Applications -: With signals from three or more satellites, a GPS receiver can triangulate its location on the ground (i.e. longitude and latitude) from the known position of the satellites. With four or more satellites, a GPS receiver can determine a 3D position (i.e. latitude, longitude, and elevation). In addition, a GPS receiver can provide data on your speed and direction of travel. Anyone with a GPS receiver can access the system. Because GPS provides real-time, three-dimensional Positioning, navigation, and timing 24 hours a day, 7 days a week, all over the world, it is used in numerous applications, including GIS data collection, surveying, and mapping.
Efforts made by India to create its own GPS & other countries-:
  1. The IRNSS constellation will give India guaranteed access to what has become a critical service in the present day – navigation satellite signals.
  2. Using its seven satellites, the IRNSS system will beam accurate navigation signals over India and up to 1,500 km from its borders. Three of those satellites have already been launched and ISRO plans to have the remaining satellites in place by the middle of next year. By adding four more satellites, India has the option to extend the area covered by its navigation system.
  3. America’s Global Positioning System (GPS), with worldwide coverage, is the leader in the field.
  4. Russia, for its part, established a similar capability with the Global Navigation Satellite System (GLONASS).
  5. Europe is therefore in the process of putting its own constellation of Galileo navigation satellites in place.
  6. China is likewise creating the BeiDou Navigation Satellite System; a regional service has already been launched and it intends to achieve global coverage by around 2020
Currently US govt, who created GPS, maintains it and makes it freely accessible to anyone with GPS receiver. But dependence on foreign controlled GPS system may not be guaranteed in hostile situations, as happened to Indian Military depending on American GPS during Kargil war. So it is always a good option to develop indigenous systems and reduce dependence on other countries.