We need to figure out if the GPS module on the DJI phanthom 3 is busted or not. THe replacement part is expensive. Can we replace it with another module?

Someone else already made an Arduino library for the DJI Phantom GPS module. http://www.rcgroups.com/forums/showthread.php?t=1995704&page=5

Someone did a full breakdown of a DJI Phantom 2 and replaced parts on it, including moving the GPS module around. Good videos: https://www.youtube.com/watch?v=iiNeLAUeCNk&list=PL163adClzxCNf3BRrOOMyPPVSwNq8T8KX

The GPS chip on there is the ublox neo-6Q for which we have the datasheet