the typical fix for non working gps on AOSP roms is to fire up a stock rom,then get a solid lock on as many satelites as possible. i personally use an app called gps status,wich will show you how many satelites youve connected to,and let you download "A-GPS" data,wich helps the satelite lock as well.
some folks simply get their location accurate to 1-3 meters in maps,and say that works as well.
after you have gps working on a stockish rom,just boot to recovery and restore or flash your AOSP rom.
it sounds crazy,but it works.
ive found that pretty much as long as you have gps working on a rom,it will work on the next one that you flash.
if that doesnt work,you could have hardware prollems,as mentioned above.