I have a Phantom 2 with a 3d HD gimlet and IOC attached. I had previous had a Cam Bus and Ground station attached to the Phantom also but have removed it to research my issue. First, I am having a problem with holding GPS position. I am in GPS mode, about 15 to 30 feet after take off and some time even if I am at 60 to 75 feet, I have experienced a drift of mare than 10 feet. It goes to a hover and holds for about 30 seconds and then begins to move backwards. DO you think I have a GPS or Compass issue, or a combination. Happened with all equipment on and then it still continues after. When I first bought the Phantom it did not have this issue. After a few hard landings in Ground Station it began to have this issue. Also, with all equipment on board I began to have a power issue. After about 40% power utilization, the Phantom would state about 10.8 in power through IOC in my 7 in LCD. Also, when it reached this level it would land itself which made me believe that the auto landing of the phantom due to power was being executed. Also after taking the Cam Bus and Ground Station equipment off the phantom, I could fly through the drain of 40% but it seemed the phantom was struggling and along with the GPS hold not working it seems that I may have had more issues. What do you all think an what would you recommend replacement of? I have a Phantom 1 and I think the GPS and the compass are the same in the Phantom 2 as in the Phantom 1, Am I correct?