Analysis of multipath effects on LEO ranging-based positioning using BPSK and BOC signals in urban areas

Abstract

Low Earth orbit (LEO) satellites have emerged as a promising solution for positioning in environments where traditional Global Navigation Satellite System (GNSS) faces challenges, such as urban canyons. However, the impact of multipath effects on LEO positioning in such urban settings remains unclear. This study investigates the influence of multipath effects on LEO ranging-based positioning, considering signals with binary phase shift keying (BPSK) and binary offset carrier (BOC) modulations. Theoretical analysis reveals that LEO signals exhibit larger Doppler differences between the direct signal and the reflected signal. This characteristic holds particular promise for mitigating multipath effects, especially when utilizing a high frequency carrier. Subsequently, the study assesses the performance of LEO range measurements and positioning under multipath conditions through a simulated LEO constellation. Comparative analyses are conducted with GNSS performance as benchmarks. Additionally, the effectiveness of BOC modulation in enhancing LEO pseudorange positioning accuracy is observed. The results demonstrate that BOC signals can achieve higher ranging and positioning accuracy than BPSK signals. This finding underscores the potential of LEO satellites as reliable alternatives for navigation in challenging urban environments, highlighting the importance of modulation techniques in optimizing positioning performance.