Software in the Loop (SITL) Simulation of Aircraft Navigation, Guidance, and Control Using Waypoints

Fixed-wing UAVs are used for a variety of purposes, including surveillance, delivery, and military operations. Waypoint navigation is extensively used in fixed-wing UAVs to autonomously guide them. However, the takeoff and landing phases require precise and conscious design due to the high risk of damage to the vehicle during these phases. This paper describes the design of an autopilot for the Cessna 172 Skyhawk using MATLAB Simulink and X-Plane. The PID controllers in the autopilot system are tuned on a SITL platform with Simulink and X-Plane. The PID controller is tuned and the effects of the coefficients on the aircraft’s response are studied. The tuned autopilot is implemented for waypoint navigation based on the haversine equations. Moreover, from a developer’s point of view, navigating using waypoints paves the way for a simpler User Interface (UI).