*6.2. Simulation of Example Mission*

This section shows a simulation of the example shooting mission described in the previous section. A simulator developed in MULTIDRONE project is used. It is based on GAZEBO [23] and the PX4 [24] SITL (Software In The Loop) functionality. GAZEBO is a well-known open source multi-robot simulator. It allows for fast robot prototyping and creation of 3D scenarios. PX4 is an open-source autopilot software, implementing a set of functionalities to fly a drone both manually and autonomously. The SITL is a functionality to use PX4 with GAZEBO, simulating drone's sensors such as Global Navigation Satellite System (GNSS) and Inertial Measurement Unit (IMU). Our simulator also uses *UAV Abstraction Layer* (UAL) [25], an open source library to interact with autonomous drones. With this simulator and our tools for media production, it is easy to run and test different examples without flying real drones but using the very same software that would run in the real system.

Recall that the mission consists of two shooting action sequences, one with a drone performing first a lateral shot (SA1) and then a static shot (SA2), and another with two drones performing an orbital shot together (SA3). In the simulation, the shooting target is simulated with a car following a straight road that the drones must track and film. Figure 10 depicts the timeline of the executed mission. Everything starts with the GET\_READY event, which makes all drones take off and go to their corresponding waypoints. Then, the START\_RACE event triggers both sequences. Finally, after 20 s, the drones come back to the home position and land.

**Figure 10.** Execution of the example mission. WP1, WP2, WP3', and WP3" are drone start positions for SA1, SA2, SA3', and SA3", respectively.

Figure 11 shows *Drone 1* doing the lateral shot while *Drone 2* and *Drone 3* are orbiting around the target. Figure 12 shows *Drone 1* doing the static shot while *Drone 2* and *Drone 3* are still orbiting (The complete simulation can be seen in: https://youtu.be/qRPXTid9dFI.).

**Figure 11.** Screenshots of drones executing SA1 and SA3 in our simulation.

**Figure 12.** Screenshots of drones executing SA2 and SA3 in our simulation.
