European GNSS for UAS Operations: Positioning and Integrity Performance Analysis in Urban Environment

The demand for unmanned aircraft system (UAS) services is steadily increasing, with the potential to generate significant economic growth and societal benefits. To facilitate UAS operations, several European Commission (EC) initiatives have bolstered the development of the U-Space: a set of new services and procedures designed to support safe, efficient and secure access to airspace for a large number of UAS. In this context, SONORA is an EC project that aims to reinforce the development of standards and regulatory guidelines for European global navigation satellite system (EGNSS)-based applications in the U-Space and to highlight the benefits of Galileo and EGNOS for efficient drone navigation. The purpose of this paper is to present the main outcomes of the second flight trial of SONORA, since the EGNSS and IMU (inertial measurement unit) dataset collected is a unique opportunity to investigate UAS navigation performance in urban environment and to assess hybridisation techniques performance and integrity. The findings will show, among other outcomes, the importance of hybridising GNSS with IMU for UAS operations, and the need to research integrity concepts that are suitable for UAS. SONORA trials aimed to collect GNSS data to characterise the behaviour of different positioning solutions integrating EGNSS and other sensors, emulating operations over Specific category and specific assurance integrity level (SAIL) III or even Certified category. Applying mitigation measures, they were performed in SAIL II inside a standard scenario (STS). Both trials assessed the performance of different GNSS technologies, including GPS, Galileo, EGNOS, future SBAS DFMC, PPP and the two new Galileo services Galileo HAS and OSNMA. The trials were included in the scope of the technical activities that have been performed to fill gaps identified in the analysis of the regulatory framework and socio-economic context of drone operations with regards to the Specific and Certified categories (i.e. the lack of regulation requirement definitions for each operation). These activities embedded also the contribution to standards with a methodology to define operation requirements, assessing the suitability of integrity algorithms for UAS operations, and studying the performance that different services provide in terms of safety for UAS environments.