Pulsar Constellation Evolution and PPP Convergence using LEO GNSS
The objective of this paper is to demonstrate the future impact of a dedicated low-earth-orbit (LEO) Global Navigation Satellite System (GNSS) on positioning, navigation, and timing (PNT), in addition to a reflective discussion on how common GNSS evaluation methods can best reflect LEO satellite dynamics. This paper will feature Xona's LEO constellation, Pulsar, at various stages of deployment in a case study comparing GPS, LEO-augmented GPS, and standalone LEO. Results include visibility and dilution of precision (DOP) analysis for Pulsar at four stages of constellation deployment, as well as two cases exploring how precise point positioning (PPP) convergence is affected by Pulsar's LEO satellite dynamics. Pulsar is highlighted in this paper for its purposeful design that allows for both GNSS augmentation through compatible signals and GNSS independence (Gala et al., 2026). As dedicated LEO satellite-based positioning becomes more prominent in the PNT industry, it is important to consider which methods are used to evaluate constellation geometry and positioning performance. By evaluating the constellation through a variety of different methods in this paper, a discussion on the future evolution of LEO navigation constellations is offered. Pulsar is compared to MEO GNSS, both as an augmentation and a standalone service, through availability, dilution of precision, and PPP convergence.