Multi-layer PNT Enabled by QZSS and LEO PNT: Analysis in the Asia Pacific Region

Elena Galletti, Masaya Murata, Kyohei Akiyama, and Satoshi Kogure

Peer Reviewed

Abstract:	In this contribution, we evaluate the impact of combining globally available LEO PNT signals and QZSS signals available in the Asia Pacific region. Amidst the global attention given to LEO PNT systems, the performance of LEO PNT services standalone or in combination with GNSS has been studied extensively. Meanwhile, the Japanese Quasi-Zenith Satellite System is undergoing a significant system evolution and service portfolio expansion. In this work, we present numerical results of PNT service area coverage and performance for combined QZSS + LEO PNT positioning. Planned QZSS evolutions to 7 and 11 satellite constellations and potential system configurations of emerging LEO PNT systems are considered. We evaluate the combined number of visible satellites and DOP performance, showing that PDOP (95%) below 3 can be achieved with LEO PNT and QZSS-7 and PDOP (95%) below 2 can be achieved with LEO PNT and QZSS-11 in the [90°E 180°E, 60°S 60°N] region. We assess the PNT performance based on simulated PNT observable data for 14 locations at different latitudes, showing that the joint DOP performance in the region enables extremely stable errors between 60ºN and 60ºS, with a maximum horizontal/vertical error difference of 0.25m/0.18m with LEO PNT and QZSS-7 and of 0.24m/0.09m with LEO PNT and QZSS-11. Assuming user positioning with L1C/L5 measurements from QZSS satellites and single frequency C-band measurements from LEO PNT satellites, horizontal/vertical errors below 0.84m/1.14m (RMS) can be achieved with LEO PNT and QZSS-7 and below 0.80m/1.01m (RMS) can be achieved with LEO PNT and QZSS-11. We also evaluate the achievable expansions of MADOCA-PPP coverage area thanks to the dissemination of the correction data to the users via LEO satellites with different dissemination strategies, and show that global dissemination of MADOCA-PPP data can be achieved with intraplane ISL between LEO PNT satellites.
Published in:	Proceedings of the 2026 International Technical Meeting of The Institute of Navigation January 26 - 29, 2026 Hyatt Regency Orange County Anaheim, California
Pages:	590 - 601
Cite this article:	Galletti, Elena, Murata, Masaya, Akiyama, Kyohei, Kogure, Satoshi, "Multi-layer PNT Enabled by QZSS and LEO PNT: Analysis in the Asia Pacific Region," Proceedings of the 2026 International Technical Meeting of The Institute of Navigation, Anaheim, California, January 2026, pp. 590-601. https://doi.org/10.33012/2026.20518
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