See Wiki for help.
git clone https://github.com/mind111/QuadcopterAR.git
cd QuadcopterAR
git submodule update --init --recursive
Additional installation for ardupilot (Linux only) (from here):
cd controls/ardupilot
Tools/scripts/install-prereqs-ubuntu.sh -y
. ~/.profile
log out and log in to make profile change permanent
https://drive.google.com/open?id=0B0w1SmLuHjCyclI0cU93Zk5Zems