ESA’s Celeste Demos 5G NTN Positioning Signals from a LEO Satellite

The European Space Agency has successfully transmitted and received 3GPP-standardised 5G positioning signals from a satellite in low Earth orbit, demonstrating how future NTN systems could provide positioning alongside communications services.

The test was conducted on 27 August using ESA's Celeste IOD-2 satellite, which transmitted S-band 5G New Radio Downlink Positioning Reference Signals (DL-PRS) and Narrowband Positioning Reference Signals (NPRS). The signals were successfully recorded on the ground and are now being analysed for positioning performance and behaviour in the satellite environment.

Rather than relying exclusively on dedicated GNSS signals from systems such as Galileo and GPS, future smartphones and IoT devices could potentially derive additional positioning information from the same LEO networks providing their connectivity. Using standardised 3GPP signals could also reduce the need for proprietary receivers and support integration with terrestrial mobile networks.

ESA's use of S-band provides frequency diversity from conventional L-band GNSS while operating in spectrum relevant to emerging satellite communications and D2D systems. The experiment also provides in-orbit evidence as industry participants push for positioning over NR-NTN and IoT-NTN to be incorporated into future 3GPP specifications, including work associated with Release 21.

Celeste's experimentation programme will continue throughout the rest of 2026, covering areas including onboard orbit determination, timing synchronisation, resilient waveforms and navigation signals across L- and S-band. Further satellites, IOD-3 through IOD-10, are planned for launch from the second half of 2027, allowing ESA to progress from single-satellite ranging to multi-satellite positioning and test communications and navigation signals operating together.