Abstract

Positioning, Navigation, and Timing (PNT) information play a vital role in everyday life of common persons. People greatly rely on Global Navigation Satellite System (GNSS)-enabled applications for navigation to reach their desired destination. However, GNSS navigation performance is highly degraded in urban environments due to the high probability of signal interruption, multipath (MP), and/or non-line-of-sight (NLOS) signal reception. Multipath and NLOS being the major causes of disrupted positioning performance for GNSS in urban environments. The navigation signals encountered various environmental factors they are reflected, refracted, diffracted, and completely blocked by high-roof buildings, bridges, and trees, thus leading to severe uncertainties in position estimation. GNSS system has gained notable advancements in terms of number of satellites, satellite geometry and signal quality. In this paper newly established constellation BeiDou Navigation Satellite System (BDS-3) performance is quantified with respect to environmental changes and compared in terms of positional accuracy. The paper also discussed the innovative current developments and status of BDS-3 in 2023. For this reason, series of field experiments were carried out at clear open and urban environment with BDS-3 and GPS mode during the observation time of 6 hours. The BDS-3 system is configured for data logging and used for the first time at Pakistan region. The positioning and navigation performance of BDS-3 is evaluated by utilizing key performance indicators e.g satellite availability, geometric distribution in terms of PDOP, and statistical accuracy measures (i.e., Circular Error Probable (CEP) and Distance Root Mean Square (DRMS)). The experimental results shows that BDS-3 provides more number of satellites, favorable satellite geometry and reduced position error compared to GPS constellation in clear open sky environment. In urban environment it is observed that BDS-3 performance is reduced/dropped due to obstructions that leads to increase the positioning inaccuracies. It is comprehended that BDS-3 system performance is less affected in urban site in terms of satellite availability, PDOP and position error as compared to GPS system. The statistical positional accuracy for BDS-3 and GPS found to be similar at clear open sky environment. BDS is more resilient to environmental factors.

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