Hello, sorry if this post already exists.
Is it possible to control(send commands) to ardupilot via UART. If yes please provide me information of how can be done and I need information about messages that can be send. Thank you.
Nico all our commands are send over UART. We are using MAVLink protocol to send commands to copter. So I would suggest you to look how MAVLink protocol works.
There are great mavproxy, mission planner, apm planner and other good gcs systems available already that you can take a look.
And take a look at Ardupilot.org too. There are a lot of guides to help you:
http://ardupilot.org/copter/docs/common-mavlink-mission-command-messages-mav_cmd.html
and MAVLink home: