Check the user's manual, and/or contact the manufacturer. We'd be guessing.
my problem is that it is showing the positions at some areas..but it is not showing at some areas....can i know does it take more time to link to satellite
You may not have line-of-site to the satellites. Buildings and hills can block GPS reception. If it reliably works elsewhere, that's likely to be what's going on.
To test it, take it outdoors and away from buildings. Turn it on and leave it for 10 minutes to see if it gets a position lock. This is ideal conditions so if you don't get a reading there there's probably something wring with the module or the supply to it.(too low voltage etc). Signal reception will be reduced if it's indoors, outside near buildings, in a metal box etc.