Hello, I want to program a drone so it can move a pre-programmed path. Anyhow, the height / distance from the ground needs to be accurate ( I want to attach a robotic arm but it needs valid data in height for its tasks ). I have the DJI Phantom 2 system because I like its long flight time. Is there a way to program it for a specific route for to fly at a a specific height? I want to give a certain height and want the Phantom 2 to adjust its height accordingly to the new distance sensor, lets say an ultrasonic sensor. Basically, i want to turn it into a robot. How can I achieve this? I know the inbuilt naza is limited in its features. Suggestions: 1. replace the naza with the ardupilot 2. find a way to communicate between with the inbult flight controller naza and my arduino 3. take the remote control and interface it to the arduino, so that the arduino controls the remote control of the Phantom 2 and gets the data from the Ultrasonic sensors onboard the Phantom 2 via a radio link? 4. is it possible to communicate with the arduino and the Phantom 2 over the canbus, so the arduino lets the phantom 2 know where to fly? Thank you for your suggestions!