hi Jason
Where those rear LEDs go to a slow flashing green there are six or more satellites locked on and your ready for flight. If you only have a flashing red LEDs after compass cal you may have a damaged GPS antenna. You'll have to open up the shell and unscrew the GPS module as the antenna is on the top side of the board. If it's cracked you have to replace it. There's one solder point on the component side and the antenna is double back taped to the board.
today i took the top of and the i couldnt find the antenne on the board

. I changed the gps that is screwed to the top of the body but that doesnt make any difference,so have search further for a solution.