I have certain requirement within which I need to use only device GPS and not use AGPS at all, even if it is available on the device.
I presume using the following permission
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
uses both AGPS and device GPS to determine location.
Please guide me through it as I haven't worked much with GPS and location and therefore does not have sound experience in it.
From Wikipedia...
Assisted GPS (abbreviated generally as A-GPS and less commonly as aGPS) is a system that often significantly improves startup performance—i.e., time-to-first-fix (TTFF), of a GPS satellite-based positioning system. A-GPS is extensively used with GPS-capable cellular phones, as its development was accelerated by the U.S. FCC's 911 requirement to make cell phone location data available to emergency call dispatchers.
Even though A-GPS may be used to speed up the time-to-first-fix (TTFF), the actual location calculation is done with traditional GPS. Its not that A-GPS is used to determine location but rather to speed up GPS location calculation.
In addition, it would always be preferable to have a short TTFF. I hope you are not confusing this with the network/WiFi derived location. Refer Location Strategies (note that there is no mention of A-GPS being used to determine the location!) and Android: location detection by Cellular Network and WiFi.
To my knowledge, the APIs do not provide much control over A-GPS (except sending some commands to clear/request A-GPS data), so may not be possible to disable A-GPS.