IRNSS wiki page[1] sums up nicely, on why indigenous navigation system is required: The requirement of such a navigation system is driven by the fact that ac

IRNSS wiki page[1] sums up nicely, on why indigenous navigation system is required: The requirement of such a navigation system is driven by the fact that access to foreign government-controlled global navigation satellite systems is not guaranteed in hostile situations. Two more IRNSS satellites will be launched by the end of 2014, and remaining three will be launched by mid 2015. So, the 7 satellite constellation will be ready by 2015. IRNSS receivers (akin to GPS receivers) can be tested by 2014 itself (4 satellites are sufficient for determining position). I've come across few vendors who already have industrial/commercial grade IRNSS receivers[2]. So, it's only a matter of time until we start seeing IRNSS receiver chips in consumer electronic devices. Missiles use satellite navigation to determine their targets. So, relying on external navigation systems is undesirable. [1] http://en.wikipedia.org/wiki/Indian_Regional_Navigational_Satellite_System http://en.wikipedia.org/wiki/Indian_Regional_Navigational_Sa... [2] http://gpsworld.com/novatel-supplies-reference-receivers-for-irnss-ground-segment/ http://gpsworld.com/novatel-supplies-reference-receivers-for...