The project aimed to develop a concept for small aircraft to obtain alternative positioning, navigation and timing (APNT) information, when conventional GPS fails, while keeping the performance and efficiency consistent with the airspace requirements. This concept took into account a number of requirements derived from navigation, operational and industry needs as well as SESAR’s vision for future ATM operations (SESAR European ATM Master Plan).
NAVISAS investigated multiple constellation satellite positioning systems with miniature atomic clock (MAC), miniature atomic gyroscope (MAG) and vision-based navigation. The project analyzed several paths for technology mergers for applications in small aircraft navigation, in particular: (i) standalone high grade inertial navigation system (INS) based on atomic gyros, (ii) hybridized multi-constellation multi-frequency system coupled with high grade INS, and (iii) vision-based navigation.
The project established the state of the art in terms of navigation techniques specifically for small A/C and commercial aviation in general and in the field of atomic clocks and atomic gyros. It also defined and carried out a number of experiments designed to clarify the state of the art on the integration of atomic clocks and atomic gyros and to progress the TRL of both technologies.
The TRL of NAVISAS atomic gyroscope reached TRL3. Envisioned performances are promising and could challenge currently used high grade laser gyros. Several solutions at the system level have been developed to reduce the price of the entire IMU system combing 3 axis gyros, accelerometers, GPS /GALILEO /GLONASS and atomic clock for application in UAV and ULA.
This project assessed a possibility of hybridization of multi-constellation multi-frequency GNSS coupled with high-grade INS. Regarding multi-frequency receivers, no real benefit could be seen from their use when compared GPS L1 signal, nevertheless they are a good backup mean in case of unintentional interference on one GNSS frequency. Multi-constellation GNSS tight coupling with INS is an interesting approach for scenarios with frequent GNSS outages and is already used in commercial aviation. Purely inertial performance of high-grade INS based on atomic gyros is expected to reach the one from currently used laser gyros. GNSS hybridization with INS-based on atomic gyros achieved TRL3 in this project.
In the scope of this project, real flights have been executed in order to assess vision-based navigation. Performances achieved for UAV and light aircraft were good (only 1 - 2 % drift was demonstrated). This technology is expected to become a standard for UAVs in the coming years. NAVISAS delivered a proof of concept and achieved TRL2 in this matter.
This project delivered operational concepts to provide a bigger picture on what value NAVISAS can bring to small aircraft and help understand what is achievable and under what conditions. The research included extensive literature review on performance based navigation documentation and clarified the relevance of specific PBN aspects to small aircraft operations. Environmental and performance constraints have been identified along with design assurance standards specific to commercial aircraft. These might impact NAVISAS in future exploitation of the project results in commercial aviation. A plan for the integration of this kind of system in aeronautics was proposed and the possible market which is available for the application of this technology was estimated.
