The LEO-PNT (Low Earth Orbit Positioning, Navigation and Timing) demonstrator mission will feature a 10-satellite constellation that will fly close to Earth to test innovative signals across various frequency bands. It will assess how a low Earth orbit fleet can work in combination with Galileo, EGNOS and other GNSS in a multi-layer approach to optimise the provision of services, increasing overall PNT resilience and robustness, and enabling new services.