A recent project funded by the European Commission has carried out technical and financial studies aiming at supporting the standardisation process for EGNSS in drones (also known as UAS or RPAS), in line with the Space Strategy for Europe regarding fostering the use of EGNSS in aviation.
As part of the EGNSS4RPAS project, dedicated flight trials were performed to understand how EGNSS can contribute to safer and more efficient drone operations in real-life scenarios in the future U-Space. The outcomes of the trials will contribute to ongoing standardisation efforts, notably by EUROCAE and ASD-STAN.
The first and second trials were organized at the ATLAS drone test facility in Villacarrillo, Spain. The first test involved one X-UAV Clouds fixed-wing drone with a 1.85-metre wingspan and two DJI multicopters performing several operations in visual line of sight (VLOS) conditions. The second test used the same fixed-wing drone which flew various flight plans in VLOS and beyond visual line of sight (BVLOS) conditions. Moreover, dynamic geo-fencing and geo-caging demonstrations were performed as well as a scenario where the drone lost the Command & Control link and was required to return autonomously to the Home Point.
Watch the video: EGNSS4RPAS Project demonstration
Citizen safety guaranteed
A third trial took place in the urban environment of Villacarrillo, placing a DJI S1000 multicopter drone in a more challenging environment for the reception of GNSS signals. This trial performed regular use cases such as building inspection or parcel delivery. Remarkably, it was the first experimental drone operation in an urban environment ever approved by the national civil aviation authority AESA, and one of the few examples of real urban operations in Europe. For this reason, a safety analysis following the Specific Operations Risk Assessment (SORA) methodology was undertaken to guarantee the safety of citizens.
In all the trials, the drones were equipped with a multi-constellation and multi-frequency receiver called MagicUT which was used to compute the EGNSS solutions and the reference trajectory using PPP. Dedicated multi-constellation and multi-frequency antennas tailored for drone missions were also installed.
Galileo improves accuracy
In open visibility conditions, the results clearly show that the use of Galileo in dual constellation with GPS significantly improves accuracy compared to GPS-only for both the horizontal and vertical dimension. The introduction of EGNOS significantly enhances the GPS-only accuracy. Looking at integrity, the protection levels are well below the requirements defined for LPV-200 in manned aviation and the availability and continuity percentages reached very high values for all EGNSS solutions during the missions.
The urban environment poses several challenges to the reception of GNSS signals. Despite having fewer satellites available, the Galileo-only solution still provides significantly better performances than the GPS-only solution. As envisaged, the performances for the combined GPS and Galileo solution yield an even greater improvement versus the GPS-only solution.
Performance are in general very stable for the in-flight phase and error glitches correspond to the take-off and landing phases, where the multipath and satellite visibility may impact the navigation solution. It is demonstrated that the combination of Galileo with GPS is a very robust solution for the urban scenario, achieving 100% of availability for all flight plans. For the in-flight phase, protections levels provided by EGNOS are a differentiator vis-à-vis other GNSS solutions and a potential enabler of critical applications requiring high levels of integrity.
European GNSS solutions – EGNOS and Galileo - were demonstrated to be a pivotal element for the safety and efficiency of drone operations even in cities. As such, EGNSS has the capability to boost the drone market and facilitate public acceptance of these new entrants. The European Commission and the GSA will continue to demonstrate the added value of EGNSS for drones and support the uptake of EGNSS-based standards in this user community.
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