Xona Pulsar Compatibility with Spaceborne GNSS Receivers

RESUMO

Low Earth Orbit (LEO) Positioning, Navigation, and Timing (PNT) systems operating in L-band Radionavigation-Satellite Service (RNSS) spectrum are rapidly emerging through both commercial and governmental initiatives. These systems are intended to complement traditional Medium Earth Orbit (MEO) constellations, such as GPS and Galileo, by providing improved satellite geometry, higher received signal power, and greater orbital diversity. As with any new RNSS deployment, ensuring compatibility with existing systems is essential to prevent harmful interference and preserve established services. While compatibility assessments for terrestrial GNSS receivers have been studied extensively, compatibility with spaceborne receivers has received comparatively little attention due to the large separation distances between MEO GNSS constellations and most spacecraft. In contrast, LEO PNT systems operate in close proximity to other satellites in LEO, making spaceborne receiver compatibility an important consideration. This paper extends the established ITU-R compatibility assessment methodology, originally developed for terrestrial receivers, to spaceborne GNSS users. The analysis evaluates the factors affecting carrier-to-noise ratio (C/N0) degradation of legacy GNSS signals in orbital environments. Results show that, although spaceborne receivers may experience higher received power levels from nearby LEO PNT satellites, such as Xona's Pulsar constellation, they can operate compatibly alongside legacy RNSS.