1) What is a GPS?
Global Positioning System or GPS, is a technology that can give your accurate position anywhere on earth (latitude/longitude). You need a GPS receiver that can receive signals from satellites.

2) Does it work in India?
Yes. It works anywhere on the planet where you can receive signals from the satellite. You will need a pretty clear view of the sky for GPS to work, so it won't work inside buildings, underground etc

3) Can civilians use GPS?
Yes it is allowed for civilian use, with no restriction. There are high-end civilian receivers available, called dual-frequency receivers, which uses part of P-code, not the full signal, and gives higher

4) Is there a fee for using GPS?
GPS is free for use. There is no subscription or monthly fees to pay. You need to buy a receiver that is capable of receiving the signals.