Image: ESA The launch of ESA’s first Celeste LEO-PNT demonstration satellites has prompted u-blox to announce it is actively assessing how Low Earth Orbit signals can complement GNSS in mass-market positioning architectures.
ESA launched the first two Celeste in-orbit demonstration satellites — IOD-1 and IOD-2 — on March 28, marking the agency’s first step toward extending satellite navigation into low Earth orbit. u-blox, working under ESA’s Navigation Innovation and Support Program (NAVISP) Element 2, is conducting a technical evaluation of how LEO signals interact with and augment established GNSS constellations such as Galileo.
The Swiss positioning firm frames LEO not as a replacement for GNSS but as an additional layer — one characterized by higher signal strength and rapidly changing satellite geometry that could accelerate convergence and improve robustness in challenging signal environments. Early integration work is underway on u-blox’s X20 GNSS platform, examining how LEO signals across multiple frequency bands can be incorporated into future receivers.
The scope of the NAVISP project includes characterization of emerging LEO signal transmissions, analysis of LEO-GNSS measurement interactions, and evaluation of how dynamic satellite geometry affects positioning performance.
“Our work within the ESA NAVISP framework allows us to better understand how emerging signal sources can complement GNSS and contribute to robust and reliable positioning performance,” said Jani Käppi, Head of Technology Positioning at u-blox.
The full Celeste demonstration constellation will ultimately comprise 11 satellites testing innovative signals across various frequency bands. ESA’s 2025 Ministerial Council further endorsed a next phase — an LEO-PNT In-Orbit Preparatory phase — and incorporated Celeste as one of three pillars of its new European Resilience from Space initiative.