End of the drone standardization tests with Europe’s GNSS systems

Jaén (Spain) was the chosen venue for the trials of the EGNSS4RPAS project for Europe-wide standardization of uncrewed aircraft (RPASs, UAVs and drones) (1). The consortium in charge of the trial is made up by GMV, VVA and FADA-CATEC, contracted by the European Commission to demonstrate the usefulness and applicability of Galileo (2) and EGNOS (2) services for drone operations. The first round of tests was conducted on 19 March, the second on 22 and 24 April, and the last on 25 and 26 June.

The common goal of the tests was to weigh up the potential performance of Europe’s navigation systems (Galileo and EGNOS) in the emerging and opportunity-packed field of drones, in relation to air traffic management or typical applications in built-up environments like package delivering, emergency healthcare products, building inspections and critical infrastructure, etc.

The European Commission is striving to demonstrate that these systems could input an added value. In each test it has therefore fitted a very-high precision receiver to each drone, comparing the positioning provided by these European systems with GPS performance. A particularly noteworthy result was the more precise and robust performance achieved when these systems are used in combination rather than standalone.

The European Parliament and Commission has recently approved the drone-operation regulation. This third round of trials in Villacarrillo represents an aviation milestone as the first in Europe ever to follow the methodology laid down in this new regulation, in particular a Specific Operation Risk Assessment (SORA) before awarding of the drone permit.

Each one of the trials has been designed with a particular purpose in mind:

• The first test (1 flight day), conducted simultaneously with 3 drones (1 fixed wing and 2 multi-rotors) on the ATLAS aerodrome, aimed to cull all possible data for making the comparison with America’s GPS and for the two systems working in combination. An assessment was also made of positioning’s knock-on effect on drone definition and operation in terms of their influence on the basic services of U-Space (Europe’s drone management airspace), such as geofencing (definition of restricted or prohibited zones). All flights were carried out on a Visual Line Of Sight (VLOS) basis due to the sheer complexity of simultaneous operations, simulating a scenario that might well occur in the future.
   
• The second two-day test involved one fixed-wing drone to assess system performance, but this time as a Beyond Visual Line of Sight (BVLOS) flight. Specifically, several dynamic geofencing service tests were conducted, involving a loss of the control signal at a distance of 12 km from the control station. In operations of this type the behavior of the positioning system is crucial, since the control signal is lost during the flight and the drone then navigates autonomously. The flights were also used to analyze the influence of the various antennas specifically designed for drones and used to receive GNSS signals.
   
• One of the main aims of the final test, carried out in a built-up area, was to evaluate the services of the first test, setting up restricted zones and sharing the performance features of the aforementioned systems. The test also stood out as the first such built-up-environment experiment for which Spain’s State Air Safety Agency (Agencia Estatal de Seguridad Aérea: AESA) has granted a permit under national regulation.

One of the most eyecatching features of the three trials was the fact that Galileo already outperformed its opposite number, GPS, even though it is being used before all constellation satellites have yet come on stream. The corrections supplied by EGNOS were also seen to improve precision to levels of under one meter in the immense majority of cases, as well as providing system-level integrity, a feature that other constellations like GPS and Galileo cannot match. This is crucial for safety critical applications. Lastly, AESA approval of permits was seen to call for a large number of contingency measures to ensure operational safety. These measures range from setting up a drone parachute system, holding previous demonstrations of diverse equipment to temporary cutting off the operation zone to remove all people not involved in the trial. All this would have to be done at a low risk level for integrity of persons, which might overly restrict drone use.

In the words of Marta Cueto Santamaría, GMV’s head of the EGNSS4RPAS project: “This project represents for GMV a chance to deepen its knowledge of GNSS in relation to drones. Identification of EGNSS’s potential added value to drones is very important for future lines of work. We hope this project contributes towards ongoing future collaboration in this field with the European Commission and the Global Navigation Satellite Systems Agency (GSA)”.

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(1) What’s the difference between an RPAS, UAV and Drone?
RPAS (Remotely Piloted Aircraft System): aircraft, communications link and uncrewed-aircraft ground station, the aircraft being operated by remote control.
UAV (Unmanned Aerial Vehicle): uncrewed-aircraft without the remote control station, regardless of whether it is piloted remotely or automatically.
Drone: uncrewed aerial vehicle.
 

(2) The European Union’s satellite navigation programs are Galileo and the European Geostationary Navigation Overlay Service (EGNOS). Galileo’s overriding goal is to offer a European alternative to the American GPS. The EGNOS system is a complement for Galileo and GPS networks, looking ahead to the future, to provide improved signal precision down to less than two meters.