In recent years, there has been a vibrating interest in the Urban Air Mobility (UAM), or in broader terms Innovative Air Mobility (IAM), with an exponential growth in the number of publications related to aerial on-demand mobility. The attention to this new mobility paradigm is driven in part by advancements in batteries, distributed electric propulsion, and autonomy technologies that are leading to the development of a new class of aircraft, commonly referred to as electric Vertical Take-Off and Landing (eVTOL) aircraft. These new eVTOL air taxis are expected to be safer, quieter, greener, less expensive to operate and maintain than existing vertical takeoff and landing aircrafts. The UAM market shows an increasing momentum, with more and more start-ups and companies emerging across the entire value chain. The eVTOL OEM sector is rapidly evolving with innovative designs and concepts being investigated and developed worldwide. In addition to the technological advancement, according to a recent survey conducted by the European Union Aviation Safety Agency (EASA), there is a positive perception of citizens on UAM, with most of the respondents (83%) thinking that the introduction of UAM will have a beneficial impact on the society. Nevertheless, UAM/IAM are probably the most demanding applications for navigation as they combine safety-critical operations, uncrewed vehicles and short time to alarm specifications.
From a research perspective, the IAM revolution already started and has been identified as one of the future solutions to urban ground congestion, pollution, and related economic losses issues, which will therefore migrate from ground transportation to air, becoming a problem for air space availability and control. eVTOL aircrafts promise to be a possible answer because they are much less complex than legacy helicopters of comparable carrying capability. On the other hand, the reduced complexity of the aeronautical structure does not imply simpler avionics for flight control, navigation, and vehicle management, which will have to address an "on board" integration problem, with more software-defined capabilities and interactions with external systems. Indeed, one of the main issues for designers is related to the batteries required for electric propulsion and their low power/weight ratio. Despite recent advances, the value of this ratio improves only by 2-3% per year. Therefore, it is of vital importance to compact as much as possible all avionic devices for the control and management of the aircraft during operations, minimizing weight, energy consumption and cost, providing at the same time, higher and faster computational performance to allow the achievement of a higher level of autonomy. Fulfilment of these requirements leads to a completely new generation of avionic systems, that need to take advantage of the most advanced technologies. According to the trend of the development and implementation pursued by eVTOL manufacturers, the common ground is the optimization of the SWaP – C factor (Size, Weight and Power – Cost) for on board avionics, still ensuring the current level of reliability and safety to achieve the airworthiness certification.
The on-board integration leverages on diverse Position Navigation and Time (PNT) technologies to grant reliable navigation in case one does not provide sufficient performance alone or is not available. The low-level data fusion between Global Navigation Satellite Systems (GNSS) and Inertial Navigation Systems (INS) is a solution, especially if new features of GNSS signals are exploited such as multiple frequencies, the enhanced navigation message content, authenticated messages, and services of the 1st generation of the Galileo program. Some of these contribute to reliable PNT data and to the design of GNSS-based devices more robust in the event of interference. Without a doubt, the problem of GNSS interference is more topical than ever, even in the aeronautical sector, as demonstrated by the recent case of GPS outage recorded in Denver in January 2022, or by very recent spoofing incidents detected in the Baltic see, where circles spoofing, previously only observed in receivers aboard ship and on land, have been observed in civil aviation.
GAUSSIAN stands for “Galileo AUthentication and GNSS/INS platforms for Secure and Safe services In Air Navigation and mobility” and addresses some aspects related to the security of IAM applications, proposing a compact navigation system powered by EGNSS. Specifically, the project introduces the processing of authenticated Galileo signals into an integrated GNSS/INS platform to achieve greater robustness against spoofing attempts, as well as better continuity and availability of PNT data. GAUSSIAN wants to smooth some concerns which originate from real needs of flight operators, leveraging advances in existing PNT technologies. In addition to the authentication of the E1 navigation messages, the project includes the decoding and application of the corrections provided by the Galileo High Accuracy Service (HAS) to improve the PNT data accuracy.
The GAUSSIAN project takes up the European Commission's indication regarding flight tests to be planned in research programs for the creation of new drone prototypes and offers flight demonstrations at 2 different sites. In Italy, the first test and demonstration campaign are planned at the C.I.R.A. headquarters on a piloted aircraft, the second demonstration is proposed in Austria with an eVTOL made available by Flynow Aviation GmbH, one of the project partners. Indeed, the consortium represents a group of entities with experience and interest in new air mobility services and integrated avionics. All partners are currently engaged in R&D activities on IAM, air vehicles management, satellite navigation and new Galileo services.
GAUSSIAN starts from existing concepts, prototypes and components developed by the proposing companies, with a strong focus on the creation of new products, while still guaranteeing an adequate level of reliability and safety to obtain airworthiness certification. The developed solution aims at increasing some safety aspects of aircraft navigation for urban air mobility services. The project results will translate into benefits for all stakeholders and for society, industry, the scientific community, and the environment, creating a scientific advantage, economic, technological, and social.
