# Unmanned Aerial Traffic Management System Architecture for U-Space In-Flight Services
## 5 Experiments
### Experimental Setup  
We have developed our UTM system architecture in ROS (Kinetic version), and the software is available online ([[https://github.com/grvcTeam/gauss](https://github.com/grvcTeam/gauss)]([https://github.com/grvcTeam/gauss](https://github.com/grvcTeam/gauss)), accessed on 26 April 2021). First, we used an airspace SITL simulation based on Gazebo [27] for system integration and preliminary tests. Then, we setup a realistic environment to run experiments in real  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Operation 2.1** & **Operation 2.2** \\ \hline ConOps & Wind turbine inspection & Forest surveillance \\ \hline UAS type & M600 (UAS\({}_{1}\)) & M600 (UAS\({}_{2}\)) \\ \hline Cruising speed & 1 m/s & 1 m/s \\ \hline Altitude (Above Ground Level) & 30–90 m & 70 m \\ \hline Operation priority & High & High \\ \hline Events involved & Jamming attack & Geofence conflict \\ \hline \hline \end{tabular}
\end{table}
Table 6: Operational parameters for the use case 2.  
Figure 11: Top views including the initial flight plans of the use case 1 (**left**) and the use case 2 (**right**). All the operations were planned in an area of the Loring aerodrome in Madrid (Spain).  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **Operation 1.1** & **Operation 1.2** \\ \hline ConOps & Precision agriculture & Powerline inspection \\ \hline UAS type & M600 (UAS\({}_{1}\)) & Atlantic I (UAS\({}_{2}\)) \\ \hline Cruising speed & 3.3 m/s & 30 m/s \\ \hline Altitude (Above Ground Level) & 40 m & 100 m \\ \hline Operation priority & Low & High \\ \hline Events involved & Loss of separation & Loss of separation \\ \hline \hline \end{tabular}
\end{table}
Table 5: Operational parameters for the use case 1.  
time with HITL simulations. These experiments were carried out within the framework of the GAUSS project, with the configuration depicted in Figure 12.  
The company EVERIS ([[https://www.everis.com/global/en](https://www.everis.com/global/en)]([https://www.everis.com/global/en](https://www.everis.com/global/en)), accessed on 26 April 2021) ran on its headquarters in Madrid (Spain) a _Remote Pilot Station_ (RPS) for each type of UAS. Each RPS has an integrated HITL simulation producing real-time telemetry data for the operating UAS, a graphical user interface to show this telemetry, and the operational information to the safety pilot (_RPS Client Application_), and an _RPS MQTT Broker_ to communicate data over the Internet. The RPS Client Application was developed by the company SATWAYS ([[https://www.satways.net](https://www.satways.net)]([https://www.satways.net](https://www.satways.net)), accessed on 26 April 2021) and it can be seen in Figure 13). Simultaneously, we ran our UTM system on a server located in Seville (Spain), connected to the Internet via a _ROS MQTT bridge_. The UAS RPS communicated with the remote UTM system exchanging JSON (_JavaScript Object Notation_) messages sent over the MQTT (_Message Queuing Telemetry Transport_) transport protocol (We used the open-source Apache Active MQ broker). Moreover, the time synchronization for the exchanged data between the remote computers was achieved thanks to an NTP (_Network Time Protocol_) server. It is important to highlight that this experimental setup is close to the real U-space ecosystem, where the UTM system would be running on a server located at a remote distance of the UAS operators.