AirSim is a open-source, cross platform simulator for drones, built on Unreal Engine. It provides physically and visually realistic simulations of Pixhawk/PX4 using either Hardware-In-The-Loop (HITL) or Software-In-The-Loop (SITL).
The main entry point for the documentation is the Github AirSim README.
The main entry point for documentation on working with PX4 is PX4 Setup for AirSim (covering both HITL and SITL).
- Using AirSim to Simulate Aircraft Inspection by Autonomous Drones (Case Study from Generalized Autonomy Aviation System (GAAS) project).