None. Everything needed for Vision Ground Station flight is built in to the Phantom 2 Vision and Vision+.
Just ensure that you are running the latest firmware (v3.04). Visit http://www.dji.com/product/phantom-2-vision-plus/download to download the latest firmware and installation instructions.
200-meter height limit
5000-meter max flight distance
3 speedsFast 8m/s, Mid 4m/s, Slow 2m/s
This could be caused by one of three things
1. You may be within an airport no-fly zone (within 8Km of major airports) or you may have no GPS lock. Move out of the no-fly zone to begin.
2. You have no GPS lock. Wait until your Phantom has full GPS lock i.e. 6 satellites or more.
3. You have not cached a map. Connect to the internet and download the map for your area.