The title of this thread is wrong and so is India's hallmark BANANA JOURNALISM.
GAGAN is not an indigenous satellite navigation system...its GPS signal enhancing system which has no own navigation capability..It completely relies on GPS / GLONASS for navigation signals..
This used to be called "differential gps"..
one or more ground stations are built and their position is calculated very accurately and stored in the system..
the ground station then compares the GPS position from GPS satlites and the Position stored..the stored position is known to be the correct pisition and any difference between the stored position and podition given by GPS satellite is calculated as error..
that error is then relayed to lther compatible receivers and they add or substract the error from their GPS pisition to get a pin point accurate position .
so thats just GPS augmentation not Indigenous navigation system...
the error signal can be relayed via ground baser radio transmitters or for more coverage...via satellite..and thats what india is doing...
i am not sure why india needs 7 satellites for this...or is there more to the system than just GPS error correction???
may be some other member can clarify this?
so he will understand kolaveri kolaveri