TrustPoint LEO PNT: Evaluating Geometric Strength, Urban Availability, and Multi-Constellation Integration

Furqan Ahmed, Patrick Shannon, George Schmitt, Anil Goparaju

Abstract:	Purpose-built Low Earth Orbit (LEO) constellations can meaningfully complement legacy Medium Earth Orbit (MEO) GNSS by adding fast-changing geometry, richer sky coverage, and additional observables. This paper evaluates TrustPoint’s Phase 1 LEO-PNT constellation across (i) standalone open-sky performance, (ii) hybrid augmentation with GPS+Galileo, and (iii) conservative urban case studies. Using a dual-shell, evenly phased architecture, we establish 24 h@1 Hz baselines showing near-uniform open-sky availability across commonly populated latitudes: 1-fold is essentially 100% and 4-fold is at or near 100% through 60° (tabulated to 75°), with typically 6–20 satellites in view depending on elevation mask. Standalone geometry is correspondingly strong, with mid-latitude median PDOP on the order of ~1.35 at a 5° mask and ~1.76 at 10°. In hybrid open-sky operation, adding TrustPoint increases instantaneous observability by several to a dozen satellites (mask-dependent), tightens mean PDOP/GDOP by roughly 15–27%, and suppresses “worst-hour” PDOP tails (maximum hourly P95 over the day) by about 15–31%, with the largest gains in the 30°–60° band. Urban performance is assessed on realistic downtown routes in New York City (static pedestrian; vehicles at two speeds) and San Francisco (low-altitude UAV) using 3-D building models and a strict line-of-sight classifier that treats NLOS-reflected paths as non-usable. Across these scenarios, TrustPoint reduces both the frequency and duration of PVT outages—trimming severe-gap tails for mobile platforms by roughly one-third to one-half, and yielding order-of-magnitude relief for a stationary street-level user—while modestly improving geometry during usable epochs. Overall, the results indicate that the TrustPoint Phase-1 constellation provides robust standalone geometry and, as an augmentation to GPS+Galileo, delivers practical continuity and resilience gains precisely where masking and multipath dominate user experience.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	2332 - 2345
Cite this article:	Ahmed, Furqan, Shannon, Patrick, Schmitt, George, Goparaju, Anil, "TrustPoint LEO PNT: Evaluating Geometric Strength, Urban Availability, and Multi-Constellation Integration," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 2332-2345. https://doi.org/10.33012/2025.20325
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In