arXiv subjects

Michael O'Meara

Publications and source records attributed to Michael O'Meara.

3 recordsLinked to original sources

arXiv2026

Xona Pulsar Compatibility with Spaceborne GNSS Receivers

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.

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arXiv2026

Xona Pulsar Compatibility with GNSS

At least ten emerging providers are developing satellite navigation systems for low Earth orbit (LEO). Compatibility with existing GNSS in L-band is critical to their successful deployment and for the larger ecosystem. Xona is deploying Pulsar, a near 260-satellite LEO constellation offering dual L-band navigation services near L1 and L5. Designed for interoperability, Pulsar provides centimeter-level accuracy, resilience, and authentication, while maintaining a format that existing GNSS receivers can support through a firmware update. This study examines Pulsar's compatibility with GPS and Galileo by evaluating C/N0 degradation caused by the introduction of its X1 and X5 signals. Using spectrally compact QPSK modulation, Pulsar minimizes interference despite higher signal power. Theoretical analysis is supported by hardware testing across a range of commercial GNSS receivers in both lab-based simulation and in-orbit live-sky conditions. The study confirms Pulsar causes no adverse interference effects to existing GNSS, supporting coexistence and integration within the global PNT ecosystem.

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arXiv2026

Xona Pulsar Single-Satellite Positioning: System Perspective and Experimental Validation

Xona is deploying Pulsar, a low Earth orbit (LEO) commercial navigation system designed to deliver resilient positioning, navigation, and timing (PNT) where traditional solutions fall short. Pulsar satellites broadcast dedicated signals optimized for commercial users. This brings rapid geometry change, strong Doppler observability, and robust timing, enabling new approaches to positioning even when only one satellite is visible. Internet of Things (IoT) applications often prioritize availability over sub-meter accuracy in urban canyons, semi-indoor spaces, and other constrained environments. Many platforms are battery-powered, have strict size, weight, and power (SWaP) limits, and cannot support complex multi-sensor architectures. Leveraging LEO dynamics and signal strength, Pulsar can maintain navigation capability under these conditions without specialized user hardware. Here we present a single-satellite positioning (SSP) concept that uses available Pulsar measurements to estimate user position and receiver clock states without external aiding. Early in Pulsar deployment, only one or two satellites may be in view, yet this still benefits stationary or near-stationary users, including in semi-indoor and indoor settings. We discuss algorithmic details and system implications: SSP enables positioning with minimal satellite visibility, reduces reliance on dense constellations, and supports integration into resource-constrained platforms. We present simulation and live sky results. High-fidelity constellation simulations configured for Pulsar provide controlled performance assessment. We also present early findings from a Pulsar-enabled receiver using observations from the Pulsar-0 satellite on orbit. Preliminary tests demonstrate meter-level accuracy outdoors and indoors, highlighting potential under varied reception conditions.

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