## 3 Results and Discussion
### Real-Time with Harware and Humans in the Loop Simulation Environment and Test Methodology
The RTS simulator was a high-fidelity simulator of the FLARE experimental vehicle that reproduced the dynamics of a TECNAM P92 Echo-S vehicle at a high accuracy level by integrating many different piloting modes:  
* Manual, in which the simulator acts as if the aerodynamic control surfaces are directly maneuvered by the pilot. * Augmented, in which the pilot's commands, in terms of attitudes rates, are sent to a stability and augmentation flight control system. * Autopilot mode, in which the pilot's commands, in terms of select and hold commands on relevant flight path variables (e.g., altitude, velocity, and track) are sent to a flight control computer (FCC) that operates as an autopilot. * The flight plan mode, in which a series of waypoints are uploaded by the pilot and the FCC defines and executes maneuvers to follow the sequence of WPs. Figure 5: Remote pilot station (RPS) and pilot’s HMI detail in the real-time simulation (RTS) environment [14]. Figure 6: Air traffic controller (ATCo) simulated working position [14]. The scenario simulator was shared between the CIRA and MATS premises. Traffic aircraft not directly involved in the separation assurance and collision avoidance tests were also included in the simulations to allow ATCos to also require traffic vehicles to operate under their instructions (to simulate proper ATCo workload during the separation assurance and collision avoidance tests). The scenario simulator embedded a GPS constellation simulator, which allowed one to send GPS-simulated data to the ADS-B simulator. The ADS-B traffic data were sent both to the RPS in order to be visualized on the pilot's CDTI system and to the ASACAS, also embedded in the simulator, which was the actual system aimed to be implemented in the vehicle FCC for the expected live flight trials after completing the RTS campaign. Finally, a safety pilot position that reproduced the TECNAM P92 cockpit instrument allocation in a very simple way, was used. The engineering working station completed the set-up: from the engineering working position, different non-nominal conditions, such as GPS signal spoofing and the C2L (Command and Control Link) jamming, could be activated. All the vehicle data and events were recorded in the FDR (Flight Data Recorder) embedded in the EWS (Engineering Workstation). All the RTS environment components were connected for data and voice communications. A synchronized virtual private network (VPN) on an Ethernet connection were established between the CIRA and MATS premises, allowing for the synchronized real-time interaction of all the simulated elements. Voice communication was again ensured by the Ethernet connection, using proprietary or freeware communications software. As far as the involved professionals are concerned, at least a professional pilot and two professional controllers were involved in each scenario simulation. In the most complex scenario, two pilots and two air traffic controllers--the remote pilot, the safety pilot, the aerodrome controller, and the terminal maneuvering area (TMA) controller--were simultaneously involved in all scenarios in which the hand-over maneuver was reproduced. A total amount of about 50 real-time simulations, involving pilots and controllers as described before, were carried out in two test campaigns. All the scenarios were simulated in different operating conditions. Nominal and non-nominal conditions were tested with various possible levels of surrounding traffic, encounter conditions, and malfunctions of the systems. Many data files were recorded:  
* Time-histories for all the position-velocity variables of the aircraft involved in the simulations. * Log files for trajectory and housekeeping data for the RPAS under test. * Audio/video recordings of the whole test sessions, both at the CIRA premises and the MATS premises. * Questionnaires submitted and filled by the pilots and controllers during de-briefing sessions.