Precise positioning is increasingly critical for applications ranging from autonomous mobility to resilient infrastructure monitoring. Current Global Navigation Satellite Systems (GNSS) provide global coverage but often suffer from weak signals, urban multipath, and interference vulnerabilities. A new study conducted extensive simulations on Low Earth Orbit (LEO) satellite-based Positioning, Navigation and Timing (PNT) systems across representative outdoor environments. The research evaluated signal power, geometry quality, positioning accuracy and interference robustness under different carrier frequencies, satellite transmission powers and constellation designs. Results show that optimized LEO constellations, particularly in hybrid mode with GNSS, significantly improve accuracy and maintain strong performance in urban scenarios where GNSS degrades.
Current Global Navigation Satellite Systems (GNSS) has supported global Positioning, Navigation and Timing (PNT) services for decades, but modern applications demand higher reliability, faster convergence, and resistance to jamming and spoofing. In dense cities or partially blocked environments, GNSS signal strength drops and multipath error increases, limiting accuracy. Meanwhile, global reliance on GNSS raises security risks should interference disable navigation. Low Earth Orbit (LEO) systems have emerged as a promising alternative, offering higher received power, better satellite geometry and broader spectrum options. Due to these challenges, researchers aim to evaluate whether LEO-PNT can complement or enhance GNSS performance through large-scale simulations and design comparisons; based on these issues, further in-depth research is necessary.
Researchers from Tampere University and Universitat Autònoma de Barcelona published (DOI: 10.1186/s43020-025-00186-5) a comparative analysis in December 2025 in Satellite Navigation . The study investigates how different LEO constellation configurations perform in positioning accuracy and interference robustness when operating alone or jointly with GNSS. Using semi-analytical modelling and 192,000 Monte-Carlo simulations, the team evaluated 400 users across European regions in five outdoor scenarios. Key variables included carrier bands (1.5/5/10 GHz), Effective Isotropic Radiated Power levels and constellation geometry design.
The team simulated multiple standalone and hybrid constellation architectures, analysing Carrier-to-Noise Ratio (C/N0), Geometric Dilution of Precision (GDOP), Position Dilution of Precision (PDOP) and lower-bound 3D accuracy. Results indicate that an EIRP of 50 dBm is sufficient for high-quality outdoor positioning when operating in L- and C-bands. While 10 GHz platforms require higher power to compensate path loss, hybrid LEO+GNSS modes show markedly improved stability and reliability.
Multi-shell constellations such as Çelikbilek-1 and Marchionne-2 delivered a favorable balance between satellite count and global geometry, outperforming single-shell layouts. In harsh urban canyon conditions, GNSS accuracy degraded up to seven-fold, whereas LEO-PNT maintained stable ranging performance with limited loss. Interference resistance also improved: stronger LEO signal power means jammers require far greater intensity to cause equal degradation. Hybrid designs provided the most significant gains. Combinations such as Çelikbilek-1 + Global Positioning System (GPS)/Galileo, or CentiSpace-like + BeiDou, yielded better PDOP distributions, faster fix availability and broader user coverage. The authors conclude that LEO systems are not aimed at replacing GNSS, but rather to enhance availability and resilience under signal-challenged environments.
"Our results show that moderate-power LEO constellations can substantially strengthen outdoor positioning without requiring expensive satellite hardware," the authors noted. "Geometry plays a major role—carefully designed multi-shell constellations achieve strong accuracy even with fewer satellites. As LEO-PNT develops, hybrid integration with GNSS offers the most cost-effective path toward secure, robust PNT solutions. This work provides guidance for future system designers evaluating frequency, transmission power and constellation configuration trade-offs."
The findings suggest a realistic rollout pathway for resilient satellite navigation. LEO-enhanced PNT could benefit autonomous vehicles, UAV routing, emergency response, precision farming and critical infrastructure monitoring—especially where GNSS falters in interference-dense or high-rise environments. Lower-power LEO transmission also reduces deployment cost, opening access for commercial operators. Future work may assess indoor positioning potential, bandwidth expansion, and real-orbit testing to refine simulation assumptions. As global demand for secure PNT grows, the integration of LEO and GNSS could become a cornerstone for next-generation navigation technology.
