Assessment of the potential of LEO-PNT systems for improving positioning accuracy in urban environments

Abstract

In recent years, there has been growing interest in the use of low Earth orbit (LEO) satellites for positioning, navigation, and timing (PNT) purposes. This article presents the results of simulations of two conceptual LEO-PNT constellations – S2-1 and S2-2 – based on parameters proposed by Teng, et al. (2023), which are an extension of the existing CentiSpace constellation. The aim of the study was to determine the impact of these constellations on positioning geometry accuracy (DOP coefficients) in open and obstructed horizon conditions, both in moderate (Poland, latitude = 51^◦) and low (Hong Kong, latitude = 22^◦) latitudes. The analysis was performed for different orbital inclination angles (31.5^◦ and 79.1^◦) and based on GNSS data and simulated TLE files for LEO-PNT. The results showed that positioning based solely on LEO satellites is possible in open horizon conditions, while in urban environments the best results were achieved using hybrid GNSS+LEO constellations, which improved DOP factors by 3–14%. Constellations with higher orbital inclinations provided better coverage and accuracy in mid-latitude regions. Research confirms that the integration of LEO-PNT systems with GNSS can significantly improve the quality of positioning geometry, especially in difficult observation conditions, and that optimal orbit design and constellation density are key to achieving high positioning accuracy.