This one is going to be quite short. Yesterday was the turn of the heading error algorithm to be tested. This heading error is calculated based on the heading the between two waypoints and heading measurement from the GPS module. This error will then be fed into a the roll controller as an input for roll command to reduce it to zero. But for the roll controller to work accordingly, the input must be right and within certain bounds. Same as the previous ground test, waypoints were loaded unto the autopilot and serial debug data was monitored using my Asus TF101 Tablet. It's worth saying that I managed to get serial data output straight from the LINUX command line . So the command line integration with VIM is complete. So it takes approximately under 10sec to upload and start debugging data of the autopilot. Sweet! Anyway, it was found that the GPS accuracy should be considered at 10-12m. Anything less than that and you'll be running for trouble. That is not a real conc