The vision for the future of GNSS in aviation is based on a multi-constellation and multi-frequency GNSS that will become a true system of systems. Such a GNSS will improve overall performance and robustness, but integrity will become more complex from the user receiver perspective. Different integrity mechanisms and concepts exist — among them, ground-based and satellite-based augmentation systems (GBAS and SBAS), Galileo safety-of-life (SoL), Galileo Open Service Signal-in-Space Accuracy (OS SISA), existing and new receiver-autonomous integrity monitoring (RAIM) concepts, and GPS III. But these are difficult to combine at the user receiver level in an efficient way.
For the user to combine systems using interoperable integrity mechanisms, the integrity information received from each of the systems must be based on the same concepts and definitions. There is a risk of having different receiver standards at regional level, and the lack of an agreed GNSS baseline on integrity could delay the ongoing transition to GNSS in aviation. Thus, reinforcing international cooperation to agree on a common base integrity mechanism will take a step towards interoperability and improved performance under a multi-constellation architecture. This integrity mechanism must be compatible with the aviation community understanding and operational concept.
Anticipated GNSS developments in terms of more constellations such as Galileo, more powerful signals in more frequency bands, and the deployment of on-board, regional, or local augmentations will overcome most of the current GPS limitations (for example, the number of satellites, single-frequency and low-power signal, and a single operator). Future GNSS receivers in aviation will process signals from at least two constellations in diverse frequency bands in combination with augmentations depending on individual business cases and the phase of flight. As GNSS become more robust, aviation will increasingly rely on GNSS data to support navigation and surveillance applications for all phases of flight, including airport operations.
GNSS developments and aviation
