# Sensors and Communication Simulation for Unmanned Traffic Management
## 3 Comprehensive Simulation Scenarios for UTM Services Validation
Regarding the GCS, its communications with the UTM system are also considered including the aforementioned telemetry relay process but also flight start and end notices, other alerts, etc. In the case of non-cooperating drones, they need to be detected and tracked making use of non-cooperating surveillance sensors. So, to assess the capability of the UTMsystem to reduce the associated risk, we need to simulate both those sensors and their communications with the UTM system. Therefore, sensors positioning and range, target detection errors (false alarms, misses, sensor precision), information processing, and track sending are implemented in the simulator. In addition, cooperative sensors must also be considered taking into account the presence/absence in a given drone of the equipment required for state message broadcasting for each surveillance technology. Finally, the communication between the actors and the UTM system would not be possible without simulating public communication networks. Thus, the simulator has the necessary mechanisms to simulate both fixed and mobile communications between the different actors, taking into account different types of network (3G, 4G, 5G) nodes forming a given architecture and the compatibility of each actor. To do so, it simulates basic forwarding and routing between those nodes and typical disturbances such as packet delays, losses, or bursts. In the case of mobile communications, the range of the nodes and the assignment of actors to each node are also considered. In relation to these last two actors (sensors and communication nodes), our simulator also models their possible failure as a contingency. Regarding the environment in which drones operate, UTM systems are designed to work with real geographic coordinates. Therefore, the geographic space on which the simulation is developed is a representation of the real physical space using the WGS84 coordinate system. Moreover, the simulator also has a digital terrain model to reproduce real topography. Meteorological information may also be simulated or obtained from real weather predictions. Weather models include parameters such as temperature, pressure, and wind speed and direction. The simulator also includes a simplified airspace model with non-flight areas defined as volumes in 4-dimensions: area, heights and time. This model is dynamic and allows the creation of new non-flight areas in simulation time. A comparison of the simulated elements in each of the existing proposals reviewed in Section 2 and the elements considered in our proposal is shown in Table 2. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{Cooperative/non-cooperative sensors} & & & & & \\ \cline{2-7}  & Drone trajectory & \(\boldsymbol{\check{\
u}}\) \\ \cline{2-7}  & Control error & \(\boldsymbol{\check{\
u}}\) & & & & & \\ \cline{2-7}  & Navigation error & \(\boldsymbol{\check{\
u}}\) \\ \cline{2-7}  & Contingencies response & \(\boldsymbol{\check{\
u}}\) & & \\ \cline{2-7} GCS & Orders and telemetry sending over C2 link & \(\boldsymbol{\check{\
u}}\) & & & & & \\ \cline{2-7}  & UTM system interaction & \(\boldsymbol{\check{\
u}}\) & & & & & \\ \cline{2-7}  & Contingencies response & \(\boldsymbol{\check{\
u}}\) & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Elements considered (\(\boldsymbol{\check{\
u}}\)) in related work and in our proposed simulator.