Here is an improved version of rmackey9's original ardupilot balloon finder.
I have modified the scripts/balloon_strategy.py file to work with the most recent version of ardupilot / Copter v3.3 (as of 2015/06/05) and to make it easier to run it from mavproxy.
I have also added a balloon/mavinit.scr to load the droneapi module and execute the balloon_strategy.py automatically when mavproxy is launched.
##Instructions
In linux, from the script folder, run linux_run_strategy.sh, and when the simulator loads up and finds the home location, insert the commands found in mavproxy_sequence.txt.
##More info
For more information, check rmackey9's repository or the original installation page here.