Labyrinth flight tests at La Nava Aerodrome in Segovia

The Labyrinth consortium visited La Nava aerodrome in Segovia on the 10th of October 2022, to perform preparatory flight tests for Labyrinth research and innovation.

A controlled scenario was used to check some of the U-Space functions and capabilities developed by the consortium. Tested functions included mission request and approval processes, conformance monitoring, U-Space tracking, static geofencing, and strategic deconfliction. All the communications between the operator´s ground control station (GCS), drones, and U-Space service provider (USSP) were done through the mobile cellular network defined and developed by the project.

During the first semester of 2023, the final concept validation of the system, including dynamic geofencing and tactical deconfliction services, will be performed. The tests shall be conducted with the end users of the consortium at CIAR facilities in Rozas Aerodrome (Lugo) for Road traffic and Emergency use cases, at Ferrol port (A Coruña), and in Marugán aerodrome (Segovia) for air transport use case. 

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Following is a brief description of the system under test and the flight tests performed.

System description

Drone system

The INTA ground control station (GCS) has been upgraded to perform mission planning, monitoring, and control of simultaneous UAVs from a single control post. This capability includes the use of commercial drones with Labyrinth-developed add-ons. The human-machine interface (fig. 1) and the high level of autonomy implemented in the system guarantee an acceptable level of the operator´s workload.

The redundant communications framework developed by Labyrinth has been implemented on the ground control station and the drones used for the project.

It includes command and control from GCS to drones, telemetry and video streaming from drones to GCS, and bidirectional communication between the GCS and USSP. Besides, redundant position reporting from drones to USSP has also been implemented.

It includes mission approval, advisories, proposed modified 4D trajectories, instructions, and static and dynamic geofences in the operation area.

The drone can also be operated using the commercial-of-the-shelf console provided by the manufacturer. If required, an external pilot can override the control from the GCS.

Figure 1. Operator´s tactical screen on GCS during the flight (10 Nov 22)

Communication network

The Universidad Carlos III de Madrid (UC3M) and Telefonica have developed a communication framework (fig.2) to facilitate communication between all stakeholders (GCS, drones, and USSP). For security reasons, when communicating over a public cellular network (5G/LTE/4G), the GCS and drones use a Virtual Private Network VPN. It is possible to transmit positioning and intention reports both from the drones and from the GCS to the USSP through HTTP requests.

Figure 2. System under test block diagram

System description of U-Space services

DLR has developed U-Space the following services:

  • Flight authorization service (U2)
  • Mission tracking (U2)
  • Mission conformance monitoring (U2)
  • Geo-fencing
  • Mission planning strategic (U2) and tactical deconfliction (U3)

The U-Space services can be accessed using an API or a webapp (fig. 3) accessible on the public network (fixed or cellular). The webapp is a way to avoid the operators to implement the graphic dialogues and information display in their GCS. The deconfliction service was developed by UC3M Robotics and implemented by the USSP.  

Figure 3. U-Space Webapp screen during the flight

Test results

The test results obtained were positive. During the test, two simultaneous flights of drones were performed. The weather conditions were mostly clear skies, 15ºC temperature and winds SE at 3 to 6m/s.

The following videos show some of the missions filmed:

Video 1. Mission M600 M300 U Space

Video 2. Tracking from M300 of minibus

Test results of drone system

Both drones were continuously monitored from the GCS. Data about the position, flight parameters, warnings, and caution signals were shown on the tactical screen. During the flight, the operator sent different flight commands to each drone using the tactical screen.

Detailed telemetry of the selected drone was presented to the operator on a secondary screen below the tactical screen. Data provided by USSP using the API was represented on the tactical screen of the pilot of GCS. It includes flight indications, dynamic geocages, new trajectories, etc., although this data was not required in this particular operation. USSP Webapp was also displayed on a redundant screen of the GCS.

Test results of communication network

The uplink and downlink communications between the GCS and the drones were excellent during the operation. No datalink loss event or interruption was noticed. Also, the communication between USSP-GCS and drones-USSP was excellent, and no datalink loss event or interruptions were noticed at the reception.

Test results of U-Space services

  • Mission plan management: Several mission requests were sent to USSP for approval using the webapp. The service was provided correctly without any incident.
  • Mission tracking: Two 4D trajectories approved for flight by USSP were simultaneously flown by two drones monitored and controlled by the same GCS. A discrepancy in the tracks provided by the drones and by the GCS was detected; GCS provided frozen values during some seconds of the flight. The failure has been identified and corrected.  
  • Mission conformance: This functionality was tested during the operation. The frozen positioning report from GCS was erroneous and produced a discrepancy concerning the positioning report sent by both drones. U-Space detected this event, and an advisory was provided in the webapp. During the initial part of the mission, a trajectory deviation for drone #2 (error<20 m) and a severe trajectory deviation for drone #1 (error>20 m) was reported by USSP. The severe deviation of drone 1 was due to the initialization of drone 1 at the beginning of the flight.
  • Geofencing: Three static geofences corresponding to the hangars of the aerodrome were defined by USSP in the operation area. A mission with intentional conflicts with the geofences was rejected, and a modified version without conflict (changing altitude) was received on the GCS to be considered by the operator of the drone.

Conclusions and next steps

Labyrinth functionalities and services have been successfully tested in a controlled scenario. The following steps are:

  • Functional testing of dynamics geofences and tactical deconfliction.
  • Perform flight tests with mission-related payload to satisfy end user´s needs.
  • Elaborate the safety analysis required to comply with actual regulations including interfaces with ATC when required.
  • Elaborate the procedures for the use cases for road transport, emergency service, and maritime transport scenarios with the relevant end users, members of the consortium, “Dirección General de Tráfico”, SAMUR, and the maritime authorities of Ferrol port.