Initial guide taken from the PX4 site http://dev.px4.io/simulation-gazebo.html
git clone https://github.com/PX4/Firmware.git
- brew tap osrf/simulation
- brew install gazebo7 # seems to be the recommended version
- pip install empy catkin_pkg # possibly more on a clean environment
- cd Firmware/ # location of your PX4 Firmware clone
- make posix_sitl_default gazebo