I am developing an android app for a usb GPS module of UBLOX. Is there any accuracy information in the raw NMEA data which i can use in my GUI? or do I have to use any algorithm to calculate the accuracy?
You may be looking for the NMEA xxGST message, e.g. GPGST for GPS satellites. See section section 18.12 of the u-blox Receiver Description Protocol Reference document for more information.