Integration of GNSS and LEO-PNT for Precise Positioning: a Simulation in Urban Environment

The demand for accurate, real-time positioning is increasing across various domains, including autonomous navigation, public safety, urban mobility, and assistive technologies. While Global Navigation Satellite Systems (GNSS) provide global coverage and reliable Positioning, Navigation, and Timing (PNT) services, their performance in dense urban environments remains a challenge due to signal obstructions, multipath effects, and interference threats such as spoofing and jamming. To enhance positioning performance in such scenarios, this study explores the integration of Low Earth Orbit (LEO)-based PNT constellations with GNSS, focusing on their impact on Precise Point Positioning (PPP) convergence time. A simulated LEO-PNT constellation of 263 satellites, operating at 1200 km altitude with polar or 55° inclined orbits, is introduced to augment GNSS observables. Using real GNSS data and an Extended Kalman Filter (EKF) approach, the hybrid GNSS+LEO system is evaluated in a simulated urban environment with a 40° elevation cutoff. The results, based on three test datasets, demonstrate a significant reduction in PPP convergence time, up to 80% improvement in challenging conditions, highlighting the potential of LEO-PNT in enabling faster and more reliable positioning solutions for future urban applications.