Arduplane is an open source Autopilot. APM aims experimented users, who wish to use the Parrot Disco and C.H.U.C.K. for experimentation.
A Ardupilot version is integrated on the firmware 1.1.0 and above. To switch from Parrot Autopilot to APM, press shortly the ON/OFF buttons 3 times in a row. Then, you must use a RC control to pilot the Parrot Disco (compatibility is listed on Parrot Github) It is possible to switch between the use of Parrot Disco with Parrot Autopilot and Skycontroller 2 or Ardupilot combined with a RC controller.
You will find all ressources necessary to build you own version of Ardupilot and install it on the C.H.U.C.K. here :