Celeste for resilience
A central element of Celeste is its exploration of advanced more powerful signals and signals in new frequency bands to enhance satellite navigation resilience, including interference situations, and open to new services capabilities directly from low Earth orbit.
With its 11 satellites, the Celeste in-orbit demonstration mission will demonstrate the use of several novel frequency bands to transmit PNT signals:
- L-band, for augmentation of legacy GNSS users.
- S-band, for enhanced positioning capabilities for handheld mass-market users
- C-band, for resilience and performance for high-end devices (professional, transportation, critical infrastructure).
- UHF (Ultra high frequency), for satellite navigation availability indoors and in harsh conditions.
L-band, the baseline of GNSS
The L-band is the baseline for PNT across all types of applications, being a good compromise in terms of propagation performance, bandwidth, and receiver terminal size and technology.
From low Earth orbit (LEO), navigation satellites can complement existing medium Earth orbit (MEO) systems by providing stronger signals and additional ranging geometry. This contributes to improved redundancy, accuracy, and robustness, especially in demanding environments like cities.
Celeste will demonstrate how satellites in LEO can relay existing current satellite navigation L‑band signals, validating precise orbit and timing performance for future multilayered architectures.
Slightly higher than L: S-band
Celeste will evaluate how this band, higher than L-band, typically used by 5G devices, can be used to provide enhanced positioning capabilities which would open a wide range of new applications combining navigation, timing and communication features like low-bandwidth, text-based communication for safety-of-life and other critical applications.
Higher than L: C-band
Operating above the L-band, the C-band shows strong resilience against interferences, both intentional like jamming and spoofing, and naturally occurring like those caused by ionospheric effects.
The introduction of C‑band navigation signals also opens opportunities for advanced code-based signal architectures, which further strengthen accuracy and resistance to interference, together with authentication concepts for resistance to spoofing.
Lower than L: Ultra-high frequency
Frequency bands below the L‑band, particularly in the UHF range, offer improved penetration through obstacles. These characteristics make UHF suitable to enable satellite navigation services in harsh environments, in forested or obstructed landscapes, in ‘urban canyons’ and indoors, where current GNSS satellites in medium Earth orbit face significant limitations.